Civil Engineering Department

The Government of the Hong Kong

Special Administrative Region

Agreement No. CE 15/99

Environmental Impact Assessment for

Demolition of Kwai Chung

Incineration Plant and

Kennedy Town CDA

Kwai Chung Incineration Plant

Final Environmental Impact Assessment (Final Report)

SeptemberJuneMay 2001

Atkins China Ltd

Client : Civil Engineering Department				Contract No. (if any) : - CE 15/99
Project Title : Environmental Impact Assessment for Demolition of Kwai Chung Incineration Plant and Kennedy Town CDA				Project No. : 2996
Document No. : 2996-OR026-0543				Controlled Copy No. :
Document Title : Final Environmental Impact Assessment (Final Report) Kwai Chung Incineration Plant
Covering Letter / Transmittal Ref. No. : 2996/15.309/ELT /DG/jw/OG				Date of Issue : SeptemberMay 2314, 2001June 2001
Revision, Review and Approval/Authorisation Records
		/	/		/
		/	/		/
05	6^th Issue	Various/	JWS/		DG/
04	5^th Issue	Various/	JWS/		DG/
03	4^th Issue	Various/	JWS/ WD/		DG/
02	3^rd Issue	Various/	WD/		DG/
01	2^nd Issue	Various/	WD/		DG/
00	1^st Issue	Various/	JWS/		WD/
Revision	Description	Prepared by / date	Reviewed by / date		App. Or Auth. By / date

Distribution (if insufficient space, please use separate paper)

Controlled Copy No.	Issued to
1-410	EPD
1 411- 456040	Civil Engineering Department
46 1- 476241-42	ACL – ELAN
48 - 65	ACE

Note : App. and Auth. mean “Approved” and “Authorised” respectively.

Table of Contents

Executive Summary

1 Introduction 1-1

1.1 Background to the Study. 1-1

1.2 Purpose and Objectives of the Assignment 1-2

1.3 Structure of the Report 1-3

2 Study Area, Sensitive Receivers, Constraints And General Approach To Demolition 2-1

2.1 Study Area Kwai Chung Incineration Plant 2-1

2.2 Sensitive Receivers and Constraints to Demolition. 2-1

2.3 Options for Demolition. 2-2

2.4 General Approach to Demolition of Buildings and Structures at KCIP. 2-4

2.5 Principles of Chimney Demolition at KCIP. 2-5

3 Asbestos Control 3-1

3.1 Site Location and Description. 3-1

3.2 Asbestos Investigation Methodology. 3-1

3.3 ACM to be Removed. 3-2

3.4 Justification of Methods. 3-8

3.5 General Safety Measures. 3-10

3.6 Programme for Asbestos Removal 3-10

3.7 Regulations, Codes of Practice and Local Requirements. 3-11

4 Land Contamination 4-1

4.1 Requirements for Land Contamination Assessment 4-1

4.2 Land Use History. 4-1

4.3 Site Inspection. 4-2

4.4 Methodology. 4-2

4.5 Sampling Locations and Analysis of Results. 4-4

4.6 Contamination Assessment 4-11

4.7 Remediation Action Plan. 4-14

5 LandFill Gas Hazard Assessment 5-1

5.1 Requirement for Landfill Gas Hazard Assessment 5-1

5.2 Scope of Assessment 5-1

5.3 Potential Landfill Hazards. 5-1

5.4 Landfill Gas Risk Assessment Methodology. 5-2

5.5 Description and History of Gin Drinkers Bay Landfill 5-5

5.6 Description of Target Activities. 5-7

5.7 Ground Between Landfill and KCIP. 5-8

5.8 Landfill Gas Risk Assessment 5-9

5.9 Proposed Protection and Precautionary Measures. 5-11

5.10 Conclusion. 5-12

6 Noise 6-1

6.1 Introduction. 6-1

6.2 Government Legislation and Standards. 6-1

6.3 Baseline Conditions. 6-2

6.4 Noise Sensitive Receivers. 6-2

6.5 Potential Sources of Impact 6-2

6.6 Assessment Methodology. 6-3

6.7 Evaluation of Impacts. 6-5

6.8 Conclusions. 6-5

7 Air Quality 7-1

7.1 Introduction. 7-1

7.2 Government Legislation and Standards. 7-2

7.3 Dust Suppression Measures. 7-2

7.4 Vehicle Emissions. 7-3

7.5 Odour. 7-3

7.6 Conclusions. 7-3

8 Water Quality 8-1

8.1 Introduction. 8-1

8.2 Government Legislation and Standards. 8-1

8.3 Baseline Condition. 8-3

8.4 Potential Sources of Impacts. 8-5

8.5 Evaluation of Impacts. 8-5

8.6 Mitigation Measures. 8-7

8.7 Conclusions. 8-10

9 Waste Management 9-1

9.1 Introduction. 9-1

9.2 Assessment Criteria and Methodology. 9-1

9.3 Waste Disposal Ordinance. 9-1

9.4 Waste Disposal (Chemical Waste) (General) Regulation. 9-2

9.5 Dumping at Sea Ordinance. 9-2

9.6 Land (Miscellaneous Provisions) Ordinance. 9-2

9.7 Public Cleansing and Prevention of Nuisance Regulation. 9-2

9.8 Additional Guidelines. 9-3

9.9 Impacts of Wastes Generated from Demolition. 9-3

9.10 Mitigation Measures. 9-7

9.11 Waste Management Planning. 9-11

10 Environmental Monitoring and Audit 10-1

10.1 Introduction. 10-1

10.2 Requirement for EM&A. 10-1

10.3 Environmental Monitoring and Audit 10-1

10.4 Event Contingency Plans. 10-2

10.5 Implementation Schedule. 10-2

10.6 Reporting. 10-2

11 Conclusions and Recommendations 11-1

11.1 Overview.. 11-1

11.2 Demolition Methodology. 11-1

11.3 Asbestos. 11-1

11.4 Land Contamination and Remediation. 11-1

11.5 Landfill Gas Hazard Assessment 11-2

11.6 Noise. 11-2

11.7 Air Quality. 11-2

11.8 Water Quality. 11-2

11.9 Waste Management. 11-3

11.10 Environmental Monitoring and Audit. 11-3

11.11 Summary of Environmental Outcome. 11-3

List of Appendices

Appendix A Preferred Demolition Methodology (Extracted From WP1 Originally Presented November 1999)

Appendix B Selected Gin Drinkers Bay Landfill Gas Monitoring Data

Appendix C Water Quality Standards

Appendix D Site Safety Precautions

Appendix E Criteria for Soil Contamination and Landfill Disposal of Contaminated Soil

Appendix F Environmental Outcome Profile

List of Tables

Table 2.1 Structures to be demolished at KCIP

Table 3.1 Main Locations of Potential ACM Investigated at KCIP

Table 3.2 Areas of ACM Identified by Functional Zone

Table 3.3 Estimated of Amount of ACM Weather Cladding

Table 4.1 Summary of Analytical Results - Soil Samples

Table 4.2 Summary of Analytical Results - Groundwater Samples

Table 4.3 Actions Required Post Demolition

Table 5.1 Qualitative Risk Assessment Matrix

Table 5.2 Qualitative Risk Assessment

Table 5.3 Landfill Gas Detection Action Plan For Works Below Ground Level

Table 6.1 Noise Standards for Daytime Construction Work

Table 6.2 Representative Noise Sensitive Receivers

Table 6.3 Anticipated Demolition/Construction Plant

Table 6.4 Anticipated Construction Plant for Soil Remediation

Table 6.5 Predicted Unmitigated Noise Levels – Demolition Plant

Table 7.1 Representative Air Sensitive Receivers

Table 7.2 Hong Kong Air Quality Objectives (mg/m³) ^(a)

Table 8.1 Water Quality Objectives (WQOs) for Victoria Harbour

Table 8.2 Summary Statistics of 1998 Water Quality of Rambler Channel (VM13/14)

Table 8.3 Summary Statistics of 1999 Water Quality of Rambler Channel (VM12/14)

Table 8.4 Comparison of Water Quality Stabndards and Groundwater Analysis

Table 9.1 Summary of Waste Management Impacts

Table 10.1 Schedule of Impacts and Mitigation Measures

List of Figures

Figure 1.1 KCIP Locality Plan

Figure 2.1 KCIP Sensitive Receivers & Constraints

Figure 2.2 Outline Zoning Plan Kwai Chung

Figure 2.3 Typical Site Hoarding

Figure 2.4 Internal Working Platforms KCIP Chimney

Figure 3.1 Cladding on the Main Incinerator Building

Figure 3.2 Plan view of Chimney Stack

Figure 3.3 Location of ACM in Chimney Flue Guides

Figure 3.4 Elevation View of Chimney Stack-Top Section

Figure 4.1 KCIP Borehole Locations and Contaminationed Locations for Remedial Actio

Figure 4.2 KCIP Borehole Locations and Contaminated Locations for Remedial Actionn

List of Abbreviations

AAP	Asbestos Abatement Plan
ACE	Advisory Council on Environment
ACM	Asbestos Containing Material
AIR	Asbestos Investigation Report
AP	Authorised Person
APCO	Air Pollution Control Ordinance
AQO	Air Quality Objective
ASR	Air Sensitive Receivers
ASTM	American Society for Testing Materials
BTEX	Benzene, Toluene, Ethylbenzene and Xylene
BOO	Building Ordinance Office
CAP	Contamination Assessment Plan
CAR	Contamination Assessment Report
CED	Civil Engineering Department
CP	Car Park
CPLD	Committee on Planning & Land Development
CZ	Consultation Zone
CSL	Registered Asbestos Consultant
DEP	Director of Environmental Protection
DSD	Drainage Services Department
EIA	Environmental Impact Assessment
EIAO	Environmental Impact Assessment Ordinance
EM&A	Environmental Monitoring & Audit
EMSD	Electrical & Mechanical Services Department
EPD	Environmental Protection Department
FIUO	Factories and Industrial Undertakings Ordinance
G I/C	Government, Institutional/Community
GDBL	Gin Drinker’s Bay Landfill
HOKLAS	Hong Kong Laboratory Accreditation Scheme
IAR	Initial Assessment Report
KCIP	Kwai Chung Incineration Plant
KCPTW	Kwai Chung Peliminary Treatment Works
LDC	Land Development Corporation
LGHAGN	Landfill Gas Hazard Assessment Guidance Note
MTIA	Marine Traffic Impact Assessment
NEDA	Non explosive demolition agent
NCO	Noise Control Ordinance
NSR	Noise Sensitive Receiver
PCDD / PCDF	Dioxins and Furans
PCWA	Public Cargo Working Area
PFBP	Public FillPublic Filling Barging Point
PAC / PAH	Poly Aromatic Hydrocarbons
PME	Powered Mechanical Equipment
PQA	Preliminary Quantitative Assessment
RAC	Registered Asbestos Consultant
RAP	Remediation Action Plan
RCP	Refuse Collection Point
RSE	Resident Site Engineer
SB	Study Brief
SR	Sensitive Receiver
TMEIA	Technical Memorandum on the EIA Ordinance
TM	Technical Memorandum
TPH	Total Petroleum Hydrocarbons
USD	Urban Services Department
WDO	Waste Disposal Ordinance
WMP	Waste Management Plan
WP1	Working Paper 1

1 Introduction

1.1 Background to the Study

1.1.1 The (EIAO) Civil Engineering Department (CED) of the Government of the Hong Kong Special Administrative Region (CED) presented to EPD a project profile for the demolition of Buildings and Structures within the Kwai Chung Incineration Plant (KCIP). A study brief (ESB-024/98) for the EIA of the demolition was issued by EPD under the EIAO in December 1998. CED subsequently compiled a Study Brief (SB) for the consultants and appointed Atkins China Ltd to provide professional consulting services for the Environmental Impact Assessment for the Demolition of the Kennedy Town Comprehensive Development AreaKwai Chung Incineration Plant (under Agreement No. CE 15/99). The detailed technical requirements of the EIAO SB (ESB-024/98) require assessment of specific impacts associated with air quality, noise, waste management, landfill gas hazard, land contamination, water quality, hazard to life, environmental monitoring and audit. Air quality and hazard assessments areare required only in the event that athe demolition adopts a blasting methodology was adopted for the demolition. Impacts on landscape, ecology, historical and cultural heritage, land use, agriculture and fisheries are not of indicated to be of concern in the SB for Agreement No. CE 15/99 which includes the requirements of the study brief issued under the EIAO (ESB-024/98).

1.1.2 The demolition of a municipal incinerator constitutes a designated project under the provisions of the Environmental Impact Assessment Ordinance (EIAO). The Kwai Chung Incineration Plant (KCIP) site, which ceased to operate in May 1997, has been decommissioned. If the project were not to proceed, the premises will progressively dilapidate and fall into disrepair, potentially causing hazard to the surrounding environment and general public and therefore demolition is required in due course. Public concerns can be summed up as being that the decommissioned plant is removed safely with the minimum of necessary disturbance to the daily routine of the local environs.

1.1.3 This EIA Report has been structured to present the key issues and available data in a form that reflects the topics indicated to be of concern as required under the SB. The preferred demolition methods have been agreed and noise, water and waste management assessments have been completed. Based on professional judgement air quality assessment is not required because of the nature, scale and location of this Project is far from and air sensitive receivers. In addition the elected demolition method will not include blasting techniques and that the requirements of the Air Pollution Control (Construction Dust) Regulation, under the APCO will apply, ensuring that air quality is in compliance with established standards and criteria. Dedicated reports on land contamination and asbestos assessments have been completed after Site Investigation and the investigations and assessments of asbestos and land contamination issues are therefore presented in summary in this EIA. A Landfill Gas Hazard Assessment has also been carried out and was also presented to EPD in a dedicated report in order to facilitate the Site Investigation process.

1.1.4 In order to satisfy the requirements of the EIA it is necessary to define clearly the nature of the works involved in the demolition process. A Working Paper (WP1 on Preferred Demolition Methodology) was presented and endorsed by the First Steering Group Meeting proponent (1^st December 1999). The development of a conceptual scheme for the demolition process reviewed in WP1 is presented at Appendix A to describe the project. The conceptual scheme for demolition of the facilities has been developed based on practical experience and current demolition practice in Hong Kong and internationally. The impacts from the demolition activities can be reasonably well defined and the level of uncertainty to the quantitative predictions has been discussed relative to the assessments in the following sections. However with respect to the remedial action required for site clean up, secondary impacts are more difficult to assess, however the uncertainties with regard to amounts of material for treatment and disposal have been discussed.

1.1.5 The KCIP is not close to any residential development but there are a number of other and sensitive engineering locations other sensitive uses (Figure 1.1). Assessment of the probability and likely consequences of accidents that might cause severe damage within the surrounding environment is related to the proposed demolition methodology. The risks, hidden costs and knock on effects of implementing any proposal which would include blasting techniques for the felling of the chimney or the main building structures makes blasting options unattractive. These issues are discussed in Ssection 2. Consequently a conceptual demolition method has been developed which avoids most of the complications associated with blasting and provides flexibility for the implementation stages of the works. The conclusion of is that non-explosive demolition methods should be used for the demolition of Kwai Chung Incineration Plant.

1.2 Purpose and Objectives of the Assignment

1.2.1 The purpose of this study is to provide information on the nature and extent of environmental impacts, and potential safety and health hazards, arising from the demolition and clearance of all buildings, structures and chimneys within the Kwai Chung Incineration Plant (KCIP) site (the proposed “Project”) and related activities taking place concurrently. This information will contribute to decisions on :-

a) the overall acceptability of any adverse environmental consequences that are likely to arise as a result of the proposed Project;

b) the conditions and requirements for the detailed design and/or demolition of the proposed project to mitigate against adverse environmental consequences and potential safety and health hazards wherever practicable;

c) the acceptability of residual impacts after the proposed mitigation measures are implemented.

1.2.2 The objectives of the Environmental Impact Assessment (EIA) study are as follows :

a) to describe the proposed project and associated works together with the requirements for carrying out the proposed project;

b) to identify and describe the elements of the community and environment likely to be affected by the proposed project and/or likely to cause adverse impacts to the proposed project, including both the natural and man-made environment;

c) to identify and qualify emission sources and determine the significance of impacts on sensitive receivers and potential affected uses;

d) to propose the provision of infrastructure or mitigation measures so as to minimise pollution, environmental disturbance and nuisance during demolition;

e) to identify, predict and evaluate the residual (i.e. after practicable mitigation) environmental impacts and the cumulative effects expected to arise during the demolition of the facilities in relation to the sensitive receivers and potential affected uses;

f) to identify, assess and specify methods, measures and standards, to be included in the detailed design and demolition of the project which are necessary to mitigate these environmental impacts and reducing them to acceptable levels;

g) to investigate the extent of side-effects of proposed mitigation measures that may lead to other forms of impacts;

h) to identify constraints associated with the mitigation measures recommended in the EIA study; and

i) to design and specify the environmental monitoring and audit requirements, if required, to ensure the implementation and the effectiveness of the environmental protection and pollution control measures adopted.

1.3 Structure of the Report

1.3.1 A description of the elements of the community and environment, likely to be affected by the proposed demolition activities is provided in Section 2. This is presented to confirm potential constraints on demolition works, due to the need to protect sensitive receivers, surrounding infrastructure and other facilities. The summary re-establishes the conclusions from WP1 to provide an overview of requirements that constrain the way the proposed Project is executed and the choice of demolition methods.

1.3.2 In addition to this introduction the EIA includes sections covering the following:

· Section 2 Study Area, Sensitive Receivers Constraints and General Approach to Demolition.

· Section 3 Asbestos Control.

· Section 4 Land Contamination

· Section 5 Landfill Gas Hazard Noise

· Section 6 Noise Air Quality

· Section 7 Air Quality Water Quality

· Section 8 Water Quality Waste Management

· Section 89 Landfill Gas HazardWaste Management

· Section 10 Environmental Monitoring and Audit

· Section 911 Conclusions and Recommendations

2 Study Area, Sensitive Receivers, Constraints And General Approach To Demolition

2.1 Study Area Kwai Chung Incineration Plant

2.1.1 The Kwai Chung Incineration Plant (KCIP) is located at Kwai Yue Road, Kwai Chung, facing the Rambler Channel and Tsing Yi South Bridge, with a site area of about 14,000 m² (Figure 2.1). The site is close to the Kwai Chung Park, the former Gin Drinkers Bay Landfill, and therefore may be impacted by contaminants and landfill gas generated from the landfill site.

2.1.2 The KCIP site is adjacent to the Kwai Chung Preliminary Treatment Works (KCPTW) and part of the KCIP site overlaps the “Sewerage Tunnel Protection Area” of the Strategic Sewerage Disposal Scheme (SSDS), administered by Drainage Services Department (DSD).

2.1.3 The KCIP site is currently zoned as “G/IC” on the approved Kwai Chung Outline Zoning Plan No. S/KC/14, with no identified long term use of the area after demolition. However, the future land use is unlikely to be residential given the close proximity of the site to Gin Drinkers Bay Landfill and the Rambler Channel Bridge. The Outline Zoning Plan for Kwai Chung is presented in Figure 2.2.

2.1.4 A Public Filling Barging Point (PFBP), located on reclaimed land (Area 30D) to the north of the KCIP, is planned to be operational in early 20052. Construction of the PFBP is scheduled to commence in 2001 for completion by the end of 2001. The PFBP is also subject to EIA under a separate EIA study.

2.1.5 The site is opposite the Rambler Channel Typhoon Shelter and Public Cargo Working Area. These facilities accommodate a range of cargo related activities including permanently moored barges.

2.1.6 The structures that remain to be demolished at KCIP are summarised in Table 2.1.

Table 2.1 Structures to be demolished at KCIP

Building	Brief Description
KCIP Chimney	Reinforced concrete construction of diameter 6m – 12m and 150m high. Internal metal flues and platforms
KCIP Buildings	High, single storey steel frame, with weather cladding, pre-cast concrete slab, reinforced concrete partitions, corrugated metal sheet external wall and roof. The overall size is approximately 83m x 92m on plan.
Weigh Bridge Office No2	Single Storey. Approximately 4m x 13m on plan.
Site Office/ Storage Buildings	Two storey high prefabricated building. Approximately 40m x 7.5m on plan.

2.2 Sensitive Receivers and Constraints to Demolition

2.2.1 This section identifies the sensitive receives (SRs) affected by the Project as defined in the EIAO and summarises the main implications of these and other nearby sensitive engineering projects and infrastructure with respect to the constraints they will place on demolition methods. The implications such sensitive locations have on the potential for explosive demolition are also noted. Sensitive receivers for KCIP and other constraints are shown in Figure 2.1.

2.2.2 There is currently no planned programme for the demolition of KCIP. A sixteen month demolition phase was assumed in the PPFS however pProfessional judgement suggests that a twelve month programme period for the demolition would be sufficient, beginning latein 20034. T However, the soil remediation programme would will follow the demolition and would last an as a cautious approach up to an additional six to eight months based on the current has been assumed to be required for this phase of the works findings of the ground contamination investigation.

Sensitive Receivers at KCIP

Residential

2.2.3 There are few SRs such as residential premises that are so close to the works at KCIP as to be severely affected by either explosive or conventional top down demolition. However residential receivers within 700m are be included in the EIA. These include locations in the vicinity of Cheung Ching Estate, Greenfield Garden and Grand Horizon (600m or more away across the Rambler Channel, Figure 2.1).

Other Sensitivities near KCIP

2.2.4 There are several engineering and other locations, which would be very sensitive to controlled demolition by implosion blasting. These include:

· The Rambler Channel marine traffic and ferry services.

· Rambler Channel Typhoon Shelter and PCWA.

· The Public FillPublic filling Barging Point (PFBP) at Area 30D0.

· The seawalls and drainage channels other infrastructure around the area.

· The 200m Sewerage Tunnel Protection Area.

· The Kwai Ching Preliminary Treatment Works.

· The Kwai Chung Park (Gin Drinkers Bay Landfill).

· The Rambler Channel Bridge.

· The Tsing Yi Bridge.

· Kwai Tai Road and heavy vehicle access.

· Container Terminal 5 (Kwai Tai Road).

2.2.5 The PPFS concluded that due to the short distances between the chimney and the surrounding structures, the high risk and lack of cost effectiveness meant that demolition of the single chimney by implosion blasting was not feasible. These conclusions have been reaffirmed in the early stages of this EIA study.

2.2.6 Engineering and other locations would be very sensitive to controlled explosive demolition. The proximity of some facilities places them at physical risk of damage from vibration or flying debris. Others would be impacted by the need to suspend services. There are also potential landfill gas hazards associated with the Kwai Chung Park (Gin Drinkers Bay Landfill). Either individually or together the impact on these facilities/works could be sufficient to dictate against the use of explosive demolition (Appendix A).

2.2.7 Explosive demolition appears to be a very high risk option and top down demolition by more conventional means has been endorsed. Site safety measures will need to be implemented the demolition phase and for the remedial action phase for the decontamination of soils, in accordance with established standards and guidelines and the findings of the landfill gas hazard assessment.

2.3 Options for Demolition

Demolition Methods

2.3.1 The draft Code of Practice for Demolition of Buildings (DCDB, Buildings Department 1998) identifies several main methods of techniques for demolition including:

· Top down methods by jack hammer, percussive or hydraulic breakers;

· Wrecking Ball;

· Implosion;

· Saw Cutting and Drilling;

· Non explosive demolition agents (NEDA);

· Thermal lance; and

· Water jet.

Implosive Methods (blasting)

2.3.2 Implosion does not offer any potential reduction in polluting impacts in the form of noise, vibration and dust (DCDB) and is not efficient for slabs and walls that will require demolition at KCIP. Site investigations have shown asbestos containing materials (ACM) are present at KCIP and there is a potential hazard with landfill gas (Sections 3 and 5 refer). Therefore the preferred method of demolition should adopt non-blastingexplosive approach. The asbestos investigation and abatement plans (summarised in Section 3) are described in detail in the dedicated Asbestos Study Report that has been reviewed by EPD.

Top-Down Methods

2.3.3 Top-down methods are applicable and efficient for all types of structure. Typical jack-hammers can reduce vibration and hydraulic breakers can reduce noise (ref. DCDB). However, machine mounted percussive breakers and toppling or breaking away structures by large machinery do not offer any potential reduction in dust, noise or vibration emissions (DCDB). Whereas these methods may not be used exclusively, in order to assume a worst case scenario a variety of these typical methods have been assumed to be used at KCIP.

Wrecking Ball

2.3.4 This method is generally suitable for dilapidated buildings but may not be applicable in this case where structures have substantial steel re-enforcement.

Other Methods

2.3.5 Potential polluting impacts in the form of noise, vibration and dust can be reduced by using methods such as circular saw cutting, wire saw cutting, and stitch drilling are effective for all structures and can reduce vibration, noise and dust. Cutting has been suggested as the method to be used on the chimney). Non explosive demolition agent (NEDA) can also reduce vibration, noise and dust but is not applicable to slabs and walls. The use of thermal lance and or high-pressure water jets would not generally be recommended unless there are no other viable alternatives. Whereas a selection of the above processes may be used by the demolition contractor for specific locations, these methods would generally result in lesser impacts (DCDB) and their use should not be precluded by limiting plant to be used on site to that used in the assessments. For the purpose of the environmental assessment these less noisy and dusty techniques are assumed not to be adopted, in order that a worst possible case scenario is assessed.

Preferred Methodology

2.3.6 The preferred demolition methodology is discussed in full in Appendix A. A variety of top down methods are assumed to be used and various articles from a suite of powered mechanical equipment has been assumed to be in use at various locations across the site throughout the demolition. The statutory provisions under the Noise Control Ordinance and Air Pollution Control Ordinance control noise and dust from such operations. Due to the presence of ACM and the potential for landfill gas the preferred method of demolition must adopt a non-explosiveblasting approach. The asbestos investigation and abatement plans are described in detail in the dedicated Asbestos Study Report that which has been reviewed by EPD.

Removal of Waste

2.3.7 The options for removal of waste relevant to this site include use of marine barges and conventional lorries.

Road Traffic

2.3.8 The estimate of waste to be disposed of indicates that up to about forty lorries per day would be required. Therefore it is estimated that during the peak of demolition process fewer than ten heavy vehicles per hour would be required to remove waste from the Site. Potential dust arising from the loading and movement of road vehicles on the site can be controlled under the Air Pollution (Construction) Dust Regulation and there are a range of practical mitigation measures (e.g. vehicle washing, haul road damping) familiar to the construction industry in Hong Kong. In addition assessments indicate that additional waste disposal road vehicles could be absorbed into the surrounding road network without undue inconvenience. Therefore disposal of waste by road is the preferred option.

Marine Barges

2.3.9 The use of barges could reduce overall road traffic impacts, however direct loading at the waterfront would not be possible at this stage, as there is no marine access to this site. A Public Filling Barging Point (PFBP), located on reclaimed land (Area 30D) to the north of the KCIP, is planned to be operational in 2005. However this programme is preliminary and may be subject to change.The PFBP is also subject to a separate EIA study.

2.3.10 This introduces the possibility of using the Kwai Chung PFBP (KCPFBP) to minimise the impact of demolition traffic on the surrounding road network for works after early 2005. If the programme for the demolition work for the KCIP can be tied in with the opening of the KCPFBP, it would be preferable to use the KCPFBP as the public filling facility for the disposal of public fill generated from this project. However such arrangements can only be confirmed at later stage. Whereas the reception areas for the PFBP at the waterfront could be used as barging points, some lorries would be needed to move suitable wastes to the waterfront. The potential for dust and waste being dropped and consequent pollution from these sources can be reduced by the use of vehicles to transport some of the waste (suitable for public filing) over a very short haul to the PFBP. The PFBP is also subject to a separate EIA study.

2.4 General Approach to Demolition of Buildings and Structures at KCIP

General Approach

2.4.1 This section seeks to illustrate some of the more general procedures for demolition that apply to KCIP. The intention is not to prescribe a precise method or provide a work specification or a demolition plan but to indicate the approach that should be taken, in sufficient detail, to illustrate the agreed methodology and progress the Environmental Impact Assessment.

2.4.2 Whereas the eventual detailed demolition plan, which would be prepared by the selected demolition contractor(s) may not necessarily adopt the precise methodology summarised here, the consultants believe that general characteristics of the methods, which do not involve blasting, are appropriate. The methods are sufficiently effective and applicable for the tasks. Where possible methods that will help reduce noise and dust nuisances have been chosen. The options selected are also broadly in line with the Draft Code of Practice for Demolition of Buildings (Buildings Department 1998). The Draft Code of Practice for Demolition of Buildings (Buildings Department 1998) shall be observed at the detailed design stage. This EIA is therefore based on the preferred top-down demolition method using the above methods such as hand held tools and mechanical breaking methods to demolish the buildings and chimney. Whereas the proponent does not envisage that other methods would be chosen, should there be any change in the demolition method, in particular if a blasting method were introduced, a further review of the EIA should be carried out to re-assess the potential environmental impacts.

2.4.3 The overriding concerns for the demolition Project will be safety and minimisation of environmental impacts. This will include the safety of the demolition operatives, safety of other workers on the site and safety of the general public, as well as protection of adjacent facilities and minimisation of nuisances. The Contractor shall also, during the course of demolition, ensure and verify that all utilities and services have been rendered safe

2.4.4 On site sorting of waste will be mandatory and the use of selective methods can minimise the effort of sorting C&D material. As indicated below (Ssection 9) effective sorting into categories before and during the demolition process can prevent the mixing of materials leading to the contamination of say concrete and masonry with putrescible materials such as wood.

Hoarding and Site Access

· Typical hoardings are shown in the indicative hoarding plan (Figure 2.3).

· Portable barricades will be used to cordon off different work zones within the site.

· The hoardings structures will be totally within the proposed Project site and access would be controlled by security guards.

· No members of the public or unauthorised persons would be allowed entry to the site.

· Only contractors’ personnel and Government officials would be allowed within the Contractor’s working area.

General Demolition Principles

· Demolition of building and structures would generally be in the reverse order to that of construction, progressive, level by level, having regard to type of construction.

· Wherever possible, external non-load bearing cladding shall be removed first.

· All asbestos containing materials shall be removed prior to commencement of demolition works, wherever possible. Other ACM may need to be removed as access is gained to particular areas and as the demolition progresses (see also Section 3).

· Overloading of any parts of the remaining structure with debris or other materials shall be avoided.

· Debris to be removed at frequent intervals and stockpiles shall not be allowed to build up unless absolutely necessary. Waste shall be removed on a daily basis as far as reasonably practicable.

· Reinforced concrete structural members shall be cut into appropriate lengths before being lowered. Crane and lifting gear shall support beams and columns whilst being cut and lowered.

· Brick walls shall be removed top to bottom in horizontal runs (<300mm deep).

· The requirements for temporary support will be determined based upon advice of the Site Engineer/AP/RSE, in line with the Draft Code of Practice for Demolition of Buildings (Buildings Department 1998).

2.5 Principles of Chimney Demolition at KCIP

Access and General Approach

2.5.1 The main site would be protected by security personnel and a high hoarding such that the public would be totally excluded from the Project.

2.5.2 The area beneath the chimney would be cordoned off and only authorised staff involved in the demolition of the chimneys would be allowed admission into the vicinity of the chimney structure.

General Approach

Upper Chimney

2.5.3 The principle of the demolition procedure for the chimney is that the chimneys will be cut into small pieces by hand held tools on the spot by operatives who would work from working platforms inside the chimney. Hydraulic breakers would be an option for use for the remaining lower portions of the chimneys.

2.5.4 The concrete supporting weather shield and the metal flues will be removed manually. The principle of the demolition procedure shall be that the chimney and flues would be cut up into pieces and these pieces lowered to the ground by derrick. To reduce dust, damping down would be a routine procedure at this stage. This method would ensure that full control of the debris and that the pieces of reinforced concrete are not left to free fall (Figure.2.4). The above mentioned method of removal of debris is only applicable to the demolition of the upper portion of the chimneys.

Lower Chimneys

2.5.5 For demolition of the lower portion, (10m from ground level or less) if hydraulic breakers were used the demolished debris would be formed as an access ramp for the hydraulic breaker to ascend to a height sufficient to gain access and demolish the remaining portion of the chimney. The demolished debris would be broken down and removed by hydraulic excavators and loaded on to trucks for transportation to the designated disposal site. During the demolition work, water sprays will be used to suppress excessive dust generated by the processes.

Preparation

2.5.6 The area surrounding the chimney would be made secure and all necessary barricades erected. Only aAuthorised personnel would be allowed into the area.

2.5.7 Two crane shafts each size 1.5m x 1.5m (approx.) would be erected inside the chimney up to 100m high. The two crane shafts would be reduced to 1m x 1m above 100m high up to 150m high.

2.5.8 A derrick would be mounted on the top of each crane shaft for hoisting & lowering of tools and debris.

2.5.9 A working platform would be constructed at a level 2m below the top of the chimney within the concrete supporting weather shield.

2.5.10 One panel of mesh flooring of the existing steel platform (>1m square) at each level would be removed to facilitate construction of the crane shaft and lowering of debris.

Sequence of Operations

2.5.11 Using hand held tools, the insulation of the flue (non-ACM) will be removed down to 2m below top level.

2.5.12 On the platform the concrete support and metal flues shall be removed hand held tools and loaded into skips for lowering down to ground level.

2.5.13 The metal flues would be flame cut into 2m maximum lengths for lowering down to ground level.

2.5.14 Using light weight chain saws, the chimney support would be cut up into pieces of maximum size 1m x 1m, each piece being secured by a cable to a derrick to ensure that when the cutting is completed the concrete is fully supported.

2.5.15 The individual pieces shall then be lowered to the ground in a safe and controlled manner, thus ensuring there will be no free falling of material.

2.5.16 The crane shaft and derrick shall be lowered by 2m. A new platform would be erected 2m below the new top level of the remaining chimney portion. The platform size would be progressively enlarged, as demolition progresses downward to accommodate the increasing diameter of the chimney.

2.5.17 This process would be repeated until only the lower 10m of the chimney remained. These remaining lower levels would be within the reach of normal, mobile hydraulic breakers. Such breakers would be on the ground and the lower portion of the chimney would be removed by these means.

2.5.18 An asbestos consultant will be required to be employed by the proponent to supervise the contractor to ensure that ACM is removed in line with the requirements of the Asbestos Abatement Plan and not accidentally removed in the demolition process.

Duration of Demolition

1.1.1The buildings and chimney at KCIP can be demolished and removed by the conventional top down demolition using hand held tools and mechanical breaking methods. In order to avoid hazards caused to the adjacent areas, all the structures and other buildings near to the chimneys would be demolished and removed prior to the demolition of the chimneys.

2.5.19

2.5.20 It is estimated that The estimated time for the completion of these works included in the PPFS was 16 months. There is at the time of writing no programme. However professional experience and advice sought from local contractors suggests 12 months would provide appear to be ample adequate time for the required scope of demolition based on the above methodology. This concurs with independent advice obtained from experienced demolition contractors. The chimney demolition would follow demolition of the main building, and weighbridge and other site offices/storage buildings. It is estimated that a further six to As a very conservative estimate up to eight months would be required have been allowed to execute the Remedial Action Plan for cContaminated sSoil based on the current findings of the ground contamination investigations.

3 Asbestos Control

3.1 Site Location and Description

3.1.1 This section summarises the work carried out to date at KCIP to identify potential asbestos containing material (ACM). The KTIP ceased to operate 1997. EPD records show that bulk asbestos removals of ACM from the KCIP wereas undertaken prior to the removal of main plant and machinery circa 1997/98. The KCIP consists of the Site areas defined in Section 2. Blasting will not be used for demolition.

3.1.2 An Asbestos Investigation Report and Asbestos Abatement Plan for the site is required under the Air Pollution Control Ordinance (APCO) prior to the commencement of any asbestos abatement work. An Asbestos Study Report (ASR) including Asbestos Investigation Report (AIR) and Asbestos Abatement Plan (AAP) have been prepared by Registered Asbestos Consultants (EPD register 1014 and 1019) based on thorough site investigations. Results are summarised in this EIA. The locations of the ACM identified conform to the available building drawings for the Site.

3.1.3 The premises is owned by the Government of the HKSAR. Under section 2 of the APCO, the owner is defined as a contractor who has the possession of a site for purposes of construction work. CED will undertake the demolition of the premises and may hand over the site to the main civil demolition contractor who would then become the owner of the premises during the demolition. The owner of the premises shall ensure that the requirements of the APCO are carried out in line with the AIR and AAP submitted to EPD by the registered asbestos consultant (CSL). CED will work out a detailed asbestos abatement programme for the sequence of the asbestos removal at the detailed design stage. In view of the multiparty nature of the works the owner will be the person liable for any accidental disturbance of ACM, and hence, should take steps to prevent such disturbance. The asbestos abatement programme shall be agreed by all parties including the supervising registered asbestos consultant (CSL),, prior to the commencement of the demolition work.

3.1.4 The most preferable approach is that wherever possible any ACM present in the chimney and building structures will be removed before commencement of the demolition works and in theory this is the preferable approach. However, experience suggests that in practice the removal of asbestos materials in certain locations may run more smoothly if both asbestos contractors and civil demolition contractors work in tandem. This has been the case with the civil demolition of the remaining buildings and structures at other large industrial locations in Hong Kong. In general this is due to the convenience of the main civil demolition contractor providing access (scaffolding etc.) to the ACM, for the asbestos contractor and avoiding duplication of effort. In other cases it may be necessary for the civil demolition contractor to remove non-ACM materials for the asbestos contractor to gain access to the ACM.

3.2 Asbestos Investigation Methodology

3.2.1 The methodology employed for the investigation into the presence of potential ACM was based upon a combination of professional judgement, sampling for potential ACM, expertise, and qualified assumptions based upon an intricate knowledge of the site layout. Plans and suitable diagrams of the site have been examined. This has enabled the visual identification of the remaining ACM, details of which are provided in the Asbestos Study Report (AIR and AAP).

Table 3.1 Main Locations of Potential ACM Investigated at KCIP

Building	Brief Description
KCIP Chimney	One reinforced concrete weather protection and support chimney, 150m high, 12m (base) to 6m (top) in diameter. Ventilation Louvres. ACM (near chimney top) Chimney Flue Guides. ACM (each of seven platform levels) Flexible joints on flue ducts (ground level)
KCIP Main Building	Reinforced concrete structure. ACM weather cladding
E & M Services Department Office / Security Building	Prefabricated Offices. ACM floor tiles and switch box arc chutes.
Weighbridge	Weighbridge Office & Vehicle Inspection Bays. No potential ACM .

3.2.2 During the investigation a cautious approach was taken to ensure that in incidences of doubt all potential ACM was treated as ACM and sampled accordingly. Consequently, sampling was undertaken using a HOKLAS accredited Registered Asbestos Laboratory as part of the Site Investigation.

3.2.3 In conducting the asbestos investigation the site was examined, adopting a systematic approach, whereby each individual functional zone was inspected and designated a reference title based on the previous use.

Access

3.2.4 All remaining ACM on the site is inaccessible to the general public. In general, the operation of the KCIP is unlikely to have given rise to any residual contamination of the buildings with ACM dust or fibre. Dust sampling was undertaken around the open areas of the site to check that no ACM dust and debris has accumulated around the former ACM components. All potential ACM has been sampled as part of the Site Investigation procedure. If present ACM is not necessarily a hazard the public but will require removal by a Registered Asbestos Contractor (RAC) before the buildings are demolished. The ACM will be removed using methods in line with codes of practice for the Safe Handling of Low Risk ACM or Removal of ACM using Full or Mini Containment and supervised accordingly. Details are presented in the Asbestos Study Report (ASR) for KCIP.

3.3 ACM to be Removed

3.3.1 All ACM will be removed as part of the demolition process. Wherever possible the ACM will be removed prior to the main demolition works. All potential ACM materials have been investigated (see ASR) and the ACM identified in the course of the investigation is summarised in Tables 3.2 and 3.3.

Main Building

3.3.2 The main building is constructed from reinforced concrete and steel with an outer weather cladding (“Galbestos”) on the sides (Figure 3.2). The weather cladding covers most of the main building. This is identical to ACM typically found at other industrial sites in Hong Kong, built in the 1960s and 1970s. Based on experience these types of material are known to be low risk materials containing the asbestos fibres bound in a mastic paint and there is therefore little chance for the liberation of fibre.

3.3.3 Although these materials have been subject to heavy rain and wind over the years, the mastic type paint is designed to resist weathering and the coating that contains the ACM has stood up well. Where located at high elevations experience suggests that these materials will be more conveniently accessed as the civil demolition contractor provides access to sections of the main building roof. The total quantity of cladding for removal is estimated in Table 3.3.

3.3.4 There is an ACM cement pipe at the Ash Bunker. This is not friable and although it has been cracked open there is little chance of fibre release if left undisturbed.

3.3.5 Staircases connect between the ground and mezzanine floor areas of the main building but there is no access to the upper roof areas. All plant and gear has been removed from the main building including the metal stairways, gantries and staircases which were removed during the earlier decommissioning. This effectively means that there is no access to the high roof structures at present. However the plans for these areas have been inspected and the only ACM indicated is the weather cladding.

3.3.6 The ground floor consists of a series of offices, workshops, canteen and ablution facilities. One ACM gasket was found at the ventilation duct outside the kitchen, which although friable, is only exposed at the edges.

Chimney

3.3.7 ACM has been identified in the chimney at KCIP. Inside the chimney are four steel flues (Figure 3.2) (Figure 3.3). The chimney structure, which can be seen from a distance, is in fact a reinforced concrete weather shield. Each of the flues formerly received exhaust gasses from gas ducts that were connected back to the main plant via the induced draft fan ducts (Figure 3.1). The steel flues are supported on a series of steel I-beams at various levels. There is a steel mesh floor at various levels and each floor is linked by a steel safety ladder that eventually emerges at a concrete floor at the top 150m level. The only means of access into the ladders and the chimney is through a metal doorway located at ground level.

3.3.8 The structures within the chimney are as shown on the available drawings. Extracts from these drawings have been included to show the construction of chimney flue guides (Figure 3.34) and the top sections of the chimney (Figure 3.45).

3.3.9 Louvres: Metal ventilation louvres with an asbestos type mastic protective paint coating have an ACM coating identical to the ACM in the weather cladding. Drawings indicate that “Galbestos”, a proprietary painted metal was used for the six louvres at the top of the chimney and the louver at the access door near the base of the chimney. The ACM is therefore bound in a non-friable matrix and there is therefore little chance for the liberation of fibres unless the materials are grossly mishandled. Where located at the top of the chimney ACM may only be accessible as the civil demolition contractor provides access and sections of the chimney are progressively dismantled (subject to confirmation).

3.3.10 Chimney Flue Guides: These are present all the way up the chimney at intervals on the flues corresponding to the intermediate metal floors within the chimney (Figure 3.4). Close inspection indicates that the ACM cement is not friable. ACM is in the form of a hard cement based plate sandwiched between the metal flues and the guide brackets in the intermediate floors. The ACM is bound in a cement matrix and not friable. This is a low risk material. Such materials will only be accessible as the sections of the chimney are progressively dismantled.

3.3.11 Base of Chimney Flues: There are eight small ACM gaskets at the sampling ports and the asbestos ribbon at the gastight doors on the four chimney flues at ground level. The ACM flexible cloth joints on the flue ducts at the base of the chimney are friable but these materials are within the chimney, not readily accessible and unlikely to undergo further major dilapidation unless deliberately disturbed.

Offices

3.3.12 A Dedicated office building with three offices on the first floor and store areas beneath is located at the north east corner of the KCIP. The ACM adhesive on the floor tiles at various locations, although damaged is not friable but is effectively encapsulated within the mastic adhesive underlayer.

Weighbridge Office No.2

3.3.13 The single storey weighbridge is located at the southeast end of the KCIP site. The weighbridge mechanism has been removed and the pit backfilled.

3.3.14 Table 3.2 summarises the ACM present and hazard assessment.

Table 3.2 Areas of ACM Identified by Functional Zone

Functional Space	Homo-genous Material	Location	Removal Prior to Civil Demolition	Homo-genous Area	Estimated Quantity Approx. (m²)	Friability	Condition	Use	Accessibility	Asbestos Material
Chimney	Asbestos Cement	Flue Guides on Platforms 1, 2, 3, 4, 5, 6 &7.	No *	Flue Guide Plates	30cm x 10cm x 1cm x 112 (four at each flue each of seven levels) Total <3m^3	No	Good	Insulation Material	Low	Type 1
Chimney	Asbestos Gasket	Flues on Platforms 2 and 1	No*	Gaskets	Eight 15cm diameter circular gaskets Total <3m^3	Yes	Good	Sealing Material	Low	Type 3
Base of Chimney	Asbestos Cloth Joints	Joint between remains of Gas Ducts on Flues at Ground Level	Yes	Flexible Joints	Four 30cm wide joints around 1metre rectangular duct openings. Total <20m^3	Yes	Fair to Good	Vibration Seal	Low	Type 2
Base of Chimney	Asbestos Ribbon	Gas door seal on Flues at Ground Level	Yes	Asbestos Gasket	Four 5cm wide joints around 1metre rectangular door openings. Total <2m^3	Yes	Fair to Good	Door Seal	Low	Type 2
Office Block	Floor Tile Adhesive	Conference Room	Yes	Floor Tile	6m x 6m	No	Good	Flooring	Low	Type 1
	Floor Tile Adhesive	Plant Manager Offices	Yes	Floor Tile	18m x 6m	No	Good	Flooring	Low	Type 1
Main Building Offices	Floor Tile Adhesive	Kitchen Office	Yes	Floor Tile	3m x 6m	No	Fair to Good	Flooring	Low	Type 1
	Floor Tile Adhesive	Laboratory	Yes	Floor Tile	10m x 11m	No	Fair to Good	Flooring	Low	Type 1
	Floor Tile Adhesive	Corridor	Yes	Floor Tile	2m x 20m	No	Fair to Good	Flooring	Low	Type 1
	Floor Tile Adhesive	Workshop Office	Yes	Floor Tile	4m x 5m	No	Fair to Good	Flooring	Low	Type 1
	Floor Tile Adhesive	Day Supervisors Office	Yes	Floor Tile	6m x 12m	No	Fair to Good	Flooring	Low	Type 1
Outside Kitchen	Asbestos Ribbon	Duct seal on ventilation above ground level	Yes	Asbestos Gasket	3cm wide joint around half metre rectangular square duct. Total <0.2m^3	Yes	Fair to Good	Duct Seal	Low	Type 2
Ash Bunker	Asbestos Cement Pipe	Fire Water Supply	Yes	Water Pipe	30cm wide pipe about 50m long. Total <20m^3	No	Fair to Good	Water Distribution	Low	Type 3
Main Building	Corrugated Metal Sheeting and Louvres	Throughout Main Building	No*	Weather Cladding	Total > 500m3 (see Table 3.3)	No	Fair to Good	Weather Protection	Low	Type 1
Debris	Asbestos Rope and Gaskets fragments	Occasional Throughout Plant	Yes	Various	Total < 10m^3	Yes	Poor	Various	Low	Types 1 & 2

* Where ACM not to be removed immediately prior to civil demolition it is assumed that the main civil demolition contractor will provide access / scaffolds etc to high level to facilitate ACM abatement and avoid duplication of effort for building scaffold etc.

Table 3.3 Estimated of Amount of ACM Weather Cladding

Functional Space	Area	Location	Area on Plan	Estimated Quantity Approx. (m²)	Estimated Quantity Rounded Up to nearest 50 m²
Main Building	East Side	Roof Above Refuse Reception Area	25m x 80m	2000	2000
		Upper Walls Refuse Reception Area	2m x 80m + 2m x 50m	160	200
	South Side	Wall Section 1	30m x 6m x 6m	1080	1100
		Wall Section 2	30m x 6m x 6m	1080	1100
		Wall Section 3	3m x 2m x 2m	12	50
	North Side	Wall Section 1	30m x 6m x 6m	1080	1100
		Wall Section 2	30m x 6m x 6m	1080	1100
		Wall Section 3	3m x 2m x 2m	12	50
		Overhang	8m x 30m	240	250
	West Side	Wall Section 1	65m x 9m	600	600
		Wall Section 2	15m x 9m	135	150
		Top Section	65 x m x 5m x 6m	1950	2000
	Main Roof				2500
	TOTAL				13000

3.4 Justification of Methods

3.4.1 Asbestos Abatement work will be carried out in line with codes of practice for Asbestos Control, Safe Handling of Low Risk ACM, or, Asbestos Work Using Full or Mini Containment Method and supervised accordingly. The CSL has concluded that the ACM to be removed appears to be in a good condition and unlikely to result in the release of asbestos fibres unless deliberately disturbed. However, some of the ACM identified is potentially friable and potentially difficult to extract and there are significant quantities overall.

3.4.2 The removal process for most of the ACM to be removed does not have the potential to liberate significant quantities of asbestos fibre if the recommended removal methods are adopted. Full containment methods are not warranted in most cases and the ACM can be demounted dismounted or cut and wrapped without risk of liberation of significant amounts of fibre using method in line with the code of practice for Asbestos Control, Safe Handling of Low Risk ACM.

3.4.3 The removal process for the ACM from the flexible joints remaining on the ducts at the base of the chimney flues does however have the potential to liberate significant quantities of asbestos fibre. Therefore full containment methods are warranted for these items only and removal methods will be in line with the code of practice for Asbestos Control, Asbestos Work Using Full Containment Method and supervised accordingly.

Chimney - Flue Guides

3.4.4 The ACM cement at the flue guides in the chimney is not friable. The location of the ACM is such that in demolition the ACM can remain undisturbed. This removal can be accomplished as the chimney flues are dismantled. When the main civil demolition contractor reaches each platform the metal sections around the flue guides can be cut out and the excised material, metal and ACM can be wrapped ready for disposal without disturbing the ACM in the flue guide. It is recommended that the sections of metal and ACM could be placed in drums or wrapped ready for disposal line with code of practice for Safe Handling of Low Risk ACM.

Chimney - Sampling Port Gaskets and Gas Tight Doors

3.4.5 The ACM at the gaskets at the sampling ports and the asbestos ribbon at the gastight doors on the chimney flues, although friable is only exposed at the edges. The location of the ACM is such that in demolition the ACM can remain undisturbed and removal can be accomplished as the chimney flues are dismantled. When the main civil demolition contractor reaches each platform or the ground floor the metal flange sections around the gaskets and doors can be cut out (as for the flue guides) and the excised material, metal and ACM, can be wrapped ready for disposal. It is recommended that the sections of metal and ACM could be lowered to ground level using the crane proposed for use on the main chimney structure. At ground level they would be lowered into a segregated area and placed in drums or wrapped ready for disposal line with code of practice on Safe Handling of Low Risk ACM.

Chimney - Ventilation Louvres,

3.4.6 The metal ACM ventilation louvres are have ACM paint which is not friable. The location of the ACM is such that in demolition the ACM can remain undisturbed and removal can be accomplished as the upper portion and lower portions of the chimney dismantled. When the main civil demolition contractor reaches the upper portion of the chimney the ACM metal painted ventilation louvres (six in number) can be dismounted unbolted and the excised material, the whole louver and ACM, can be brought to ground level. It is recommended that the sections of metal and ACM could be lowered to ground level using the crane proposed for use on the main chimney structure. At ground level they would be lowered into a segregated area and placed in drums or wrapped ready for disposal line with code of practice on Safe Handling of Low Risk ACM. The ventilation louver over the access door to the chimney near ground level can be dealt with conveniently in a similar manner.

Chimney – Duct Flexible Joints

3.4.7 The ACM flexible cloth joints at the base of the chimney are friable but these materials are within the chimney, not readily accessible and unlikely to undergo further major dilapidation unless deliberately disturbed. The CSL has concluded that the ACM to be removed appears to be in a good condition and unlikely to result in the release of asbestos fibres unless deliberately disturbed. However, some of the ACM identified is potentially friable and potentially difficult to extract and there are significant quantities. The removal process for ACM has the potential to liberate significant quantities of asbestos fibre. Therefore full containment methods are warranted. It is proposed that a full containment be erected around the base of the chimney up to a height of about 5m and the ACM removed in line with code of practice on Asbestos Control Using Full Containment.

Kitchen Ventilation Duct Gasket

3.4.8 The ACM gasket at the ventilation duct outside the kitchen although friable is only exposed at the edges such that in demolition the ACM can remain undisturbed and removal can be accomplished as the duct is dismantled. When the main civil demolition contractor reaches the kitchen area the metal flange sections (minimum 20cm each side) around the gasket can be cut out and the excised material, metal and ACM, can be wrapped ready for disposal. It is recommended that the sections of metal and ACM could be lowered to ground level by block and tackle. At ground level they would be lowered into a segregated area and placed in drums or wrapped ready for disposal line with code of practice on Safe Handling of Low Risk ACM.

Floor Tiles

3.4.9 The ACM adhesive for the vinyl floor tiles could be exempted from the appointment of a RAC under s75(4) of the APCO since the works involve solely demolition processes. However given the extent of the other ACM abatement works it may be convenient for the proponent to include the abatement of this ACM in a contract for the RAC. The ACM adhesive on the floor tiles, although cracked in places, is are not friable. Any ACM is effectively encapsulated within the mastic adhesive underlayer and can be easily prised from the floor using scrapers and moderate force. Such force and methods are unlikely to cause the flooring to crumble in such a way as to release the ACM fibres. Therefore whereas the flooring in the individual offices will require segregation, work can be carried out in line with code of practice on Safe Handling of Low Risk ACM.

Cement Water Pipe

3.4.10 The ACM cement pipe at the Ash Bunker is present as twelve sections of 20cm diameter pipe of varying lengths up to 5m long. The material is not friable and although it has been cracked open there is little chance of fibre release if left undisturbed. The asbestos fibres are effectively encapsulated within the cement that can be easily lifted from its joints by hand or using a lifting device such as a block and tackle secured to the steel beams of the ash bunker frame above. The pipe can be lifted by exercising a moderate force. Such force and methods are unlikely to cause the pipe to crumble in such a way as to release the ACM fibres. Therefore whereas the area adjacent to the pipe will require segregation, work can be carried out in line with code of practice on Safe Handling of Low Risk ACM.

Metal Weather Cladding

3.4.11 The ACM weather cladding covers most of the main building. Although these materials have been subject to heavy rain and wind over the years, the mastic type paint is designed to resist weathering and the coating that contains the ACM has stood up well. Although cracked and bent in places there is little chance of fibre release if left undisturbed. It is proposed that the individual sections be unbolted and dismounted from the steel supporting beams. Using a crane these can then individually be lowered to ground level for wrapping and disposal in line with code of practice on Asbestos Control for Removal of Low Risk ACM.

3.5 General Safety Measures

3.5.1 Whereas this location is not manned on a daily basis (other than a security guard) some local maintenance work may be carried out periodically on the chimney lighting until such time as the demolition takes place. Routine non-essential maintenance work shall be suspended during the asbestos abatement work and local staff shall be made aware that the subsequent abatement works are to be progressed. Access shall be restricted to essential asbestos abatement staff for the duration of the removal works, as far as is reasonably practicable. Detailed of procedures for abatement and emergencies are dealt with in the Asbestos Study Report (Part 2 Asbestos Abatement Plan).

3.5.2 It is noted that all remaining ACM on the site is not accessible to the general public. In general, the operation of the Premises has not given rise to any residual contamination of the buildings with ACM dust or fibre. Routine sampling, undertaken around the site, to check that no ACM dust and debris has accumulated around the potential ACM components, does not indicate contamination of the site. A few small pieces of gasket and rope which have been discarded are not a hazard to the public but will require clean up and removal by the appointed Registered Asbestos RAC (RAC) before the main abatement works commence.

3.5.3 The ACM will be removed using methods in line with codes of practice for the Asbestos Control Safe Handling of Low Risk ACM or Asbestos Work Using Full or Mini Containment Method and supervised accordingly.

3.6 Programme for Asbestos Removal

3.6.1 In this project, the materials around the ACM, in some cases, will be dismantled by the civil demolition contractor, leaving the ACM in-situ (undisturbed). by the civil demolition contractor and The work actually involving the removal of ACM, that involves the handling of the ACM (except those exempted by the APCO) shall be carried out by an RAC. the The multi-party nature of the project and the involvement of non-asbestos contractor increase the risk of accidental disturbance of ACM. The proponent should ensure that there is a reliable supervision and co-ordination mechanism to guard against any accidental disturbance of the asbestos containing material (ACM) by non-asbestos professionals.

3.6.2 An RAC (Registered Asbestos Contractor) shall be totally responsible for completing the asbestos abatement within the given time frame. It is anticipated that a minimum of 10 to 20 competent workers in various trades would be employed over the whole abatement period. The RAC will control and monitor their work progress and make the necessary adjustment to their workforce to meet the work requirements. A full time Safety Supervisor shall be required to assist the contracting regarding safety and health of the site personnel and to keep the necessary records.

3.6.3 The statutory 28 days notice period following the acceptance of the AAP and the notification of the abatement works must elapse before the RAC can commence the work on the site.

3.6.4 The preliminary estimates for completion time after the site hand-over and the dates of each zone will need to be determined in tandem with the demolition plan of the chosen main civil contractor at a later stage and confirmed to EPD. However at this stage no details of such plans are available and it is considered reasonable that the whole demolition process may take place over a twelve-month period. although sixteen months has previously been proposed in the PPFS stage.

3.6.5 At this stage the RAC has not been appointed. The detailed asbestos abatement programme for interfacing between the RAC (possibly sub-contracted) and the main civil demolition contractor may affect the works. However a detailed asbestos abatement programme shall be presented with tenders. The final asbestos abatement programme will be determined by the CSL in liaison with CED and the appointed RAC and EPD will be informed at a later stage.

3.6.6 The final asbestos abatement programme will be passed to EPD prior to the commencement of abatement works. The programme should provide details of the asbestos abatement work, particularly the interface between the RAC and the main civil demolition contractor in order to demonstrate how the ACM would not be disturbed by unnauthorised parties. Any subsequent amendments will also be passed to EPD prior to the reprogramming of abatement works so as to keep the authorities up to date with the works. In view of the large scale of the demolition and significant duration of the work it is recommended that the supervising registered asbestos contractor should prepare a regular monthly progress report to be submitted to EPD for reference.

3.7 Regulations, Codes of Practice and Local Requirements

Statutory Obligations.

3.7.1 Notwithstanding the RAC’s statutory obligations under the General Conditions of Contract, the RAC shall comply with the all conditions, requirements and recommendations contained in all relevant current legislation, Codes of Practice and Guidance Notes issued from time to time by the Government. The relevant Codes of Practice that have particular relevance to the works have been reviewed in the Asbestos Study Report and shall be strictly followed.

3.7.2 EPD shall be given 28 days advance notice of the commencement of to commence the works in line with the AAP. Relevant information and any proposed modifications to the AAP shall be forwarded to EPD for agreement in advance ofby giving 28 days advance notice of commencement of to commence the works.

4 Land Contamination (KCIP)

4.1 Requirements for Land Contamination Assessment

4.1.1 The Professional Persons Environmental Consultative Committee (ProPECC) Practice Note for Professional Persons PN 3/94 ‘Contaminated Land Assessment and Remediation’ issued by the Environmental Protection Department (EPD) sets out procedures and requirements with respect to the assessment of land contamination.

4.1.2 ProPECC PN 3/94 advises that professionals who are involved in the demolition of sites related to certain industrial land uses shall give attention to the management requirements and guidelines contained therein. In this way the risks or hazards associated with potentially contaminated sites can be avoided or minimised. A number of industrial land uses are identified in ProPECC PN 3/94 as having the potential for causing land contamination. Of relevance to the current study, these include:

· oil installations (e.g. oil depots and oil filling stations);

· power plant;

· chemical manufacturing / processing plants; and

· car repairing / dismantling workshops.

4.1.3 Further, in cases where the Environmental Impact Assessment Ordinance (EIAO) is applicable, the preparation of a Contamination Assessment Plan (CAP) must be undertaken in accordance with the information and recommendations contained in Annex 19, Section 3 of the Technical Memorandum on Environmental Impact Assessment Process. The CAP and CAR/RAP shall be submitted before the commencement of any construction (demolition in this case) on or in potentially contaminated sites.

4.1.4 The Contamination Assessment Report (CAR) which includes reference to necessary remedial action has been produced in tandem with this EIADFR. The objectives of the CAR submitted prior to this EIADFR are to:

· describe previous and current land uses within the study area;

· report the results of site inspections from the perspective of potential land contamination; and

· present the results of the soil contamination investigation and recommendations for soil remediation or further work with respect to intrusive investigations for soil testing.

4.1.5 The CAR reports in detail the work to investigate the extent and nature, if any, of land contamination at the Kwai Chung Incinerator Plant (KCIP).

4.2 Land Use History

4.2.1 The study area is situated on flat reclaimed land which is located at Kwai Yue Road, Kwai Chung, facing the Rambler Channel and Tsing Yi South Bridge, with a site area of about 14,000 m². (Figure 2$.1). It is understood that the existing incinerator compound was the first use of the reclaimed land. On the basis of the information available it is therefore reasonable to assume that any significant contamination present on the site would have been caused by the recent land use. Inspection of aerial photographs has not provided any additional useful information.

4.2.2 The former incineration compound was used for the following activities:

· collection of waste;

· incineration of waste;

· sorting of wastes; and

· storage of fuel and chemicals.

4.2.3 Hydrocarbons were stored on site in the form of diesel fuel for the incinerators, ancillary equipment and pumps. Lubrication oils and other maintenance chemicals were also stored around the site. The main fuel tanks were above ground. Other maintenance materials would have been stored in workshops around the site.

4.3 Site Inspection

4.3.1 Site inspection was undertaken by Consultants in October and November 1999 and February 2000 in order to establish existing site conditions and to identify potential locations for further intrusive investigation. Site investigation was carried out in May 2000. Works included the drilling of 23 boreholes and the extraction of soil samples from various depths. Groundwater samples were also taken where available.

4.3.2 The KCIP area has been vacant since 1997/8. The ground over the whole site was covered in thick concrete which was established over fill materials which were identified from previous site investigation (circa 1975) ground profiles as completely decomposed granite with broken boulders, cobbles and concrete. The possibility of contamination was reviewed with respect to site conditions and former activities around the site.

4.3.3 On the basis of the preliminary site investigation it was evident that few if any surface areas of the site were heavily contaminated with fuel and lubricants or other materials as a result of site storage. Nevertheless former site operators could have resulted in some land contamination and, although the principal work areas are covered with thick concrete hardstanding, there may be cracks in this surface and it was considered possible that contamination of sub-surface layers may have occurred. It was therefore proposed that intrusive investigations were undertaken to establish the presence of any such contamination. A contamination assessment plan was agreed with EPD based on sampling at certain potential hotspots and also across the site, in line with ProPECC PN 3/94. The planned investigation was completed in line with the CAP.

4.4 Methodology

Criteria

4.4.1 Criteria for the assessment of land contamination levels are taken from the ‘Dutch List’ as specified in the Study Brief in respect of the analytical parameters. Currently in Hong Kong Dutch B level is used in most cases for the remediation target. It is noted that these criteria are the same as those presented in Appendix IV of ProPECC PN 3/94. With respect to the Dutch criteria there is no criterion for dioxins and furans PCDD/PCDF therefore the USEPA criterion of 1ppb TEQ (1ng/g, Toxicity Equivalent Unit) is proposed as the assessment criterion above which remedial action may be indicated. This criterion has been used as the remediation target for residential sites in the USA. Given that the KCIP site is currently zoned as “G/IC”, with no identified long term use of the area after demolition and the future land use is unknown the above criteria are considered conservative.

Sampling Protocol

4.4.2 Appendix II of ProPECC PN 3/94 recommends sampling protocols for soil and groundwater samples. Borehole sampling locations are indicated in Figure 4.1. Sampling locations are on a hot spot system under the areas of the former plant most likely to have given rise to ground contamination. The approach has allowed potential hotspots to be identified and provided sufficient site coverage in line with PROPECC PN3/94 recommendations.

4.4.3 The original CAP estimated about twenty boreholes and recognised the locations as provisional and that they could be subject to alteration following confirmation of subterranean utilities and services and access. In practice the positions of only three boreholes (B1, B4 and B5) were adjusted significantly. Three additional boreholes were also drilled based on the recommendations of the contaminated land specialist and site observations during the intrusive investigation.

4.4.4 Boreholes were drilled through the surface concrete layers using only mains water as a lubricant to the drilling bits. Cores were extracted laid in boxes, photographed and inspected on the spot by the contaminated land specialist. Drilling continued to a minimum depth of 3.0m or to a greater depth as instructed by the contaminated land specialist. General soil conditions and a brief description of the materials encountered at the proposed sampling depths were made. A slotted PVC standpipe was inserted into each borehole to facilitate groundwater sampling.

Soil Sampling

4.4.5 The site is on reclaimed land and, as proposed, soil samples were generally taken at three depths for each location, as far as practicable. The nominal depths 0.5m, 1.5m and 3.0m were generally adopted as a starting point with sampling depths varied depending on the materials encountered. In practice there was a heavy concrete cover of at least one metre to many boreholes and the top sample was taken at the level below ground where soil was first encountered. Middle samples were generally spaced between the top sample and the bottom sample. Extra samples were taken as warranted by observations on the extracted materials. If contamination was clearly observed at certain depths, additional samples were taken from those depths. Extra samples at deeper levels were also taken significant contamination was encountered at the deepest nominal sample.

4.4.6 In practice the rock head was not encountered very near the surface (say<2.0m) in many cases but a contingency existed to vary the sampling pattern and take fewer than three samples if necessary. Variations in the pattern of sampling were made depending on the presence of significant visible contamination. A contaminated land specialist was present during all stages of the sampling to instruct and amend sampling strategies at the time of sampling as necessary to take account of particular site conditions.

Groundwater Sampling

4.4.7 Groundwater accumulated in most boreholes rapidly after the completion of the drilling. Water levels were checked on 13^th and 24^th May 2000. A baler was used to remove water from the boreholes as necessary. The boreholes were baled out (purged) to remove groundwater and allow replenishment on 26^th and 27^th of May. Samples were taken between 29^th, 30^th, 31^st May and 1^st June 2000 as groundwater accumulated in the boreholes.

4.4.8 Whereas groundwater was encountered at the final drill depth in all boreholes, insufficient water accumulated in some boreholes to allow all parameters to be analysed as planned, due to the large volume of water required for say PCB and dioxin and furan analyses. In some cases replacement samples were taken from the nearest borehole with available groundwater if the parameter in question was not already sampled in the nearby location. E.g. whereas, it was planned to sample PCB in B1, B2, B3, B4, B5, B6, B7, B8, B9, B15, B16, B19 and B20 in practice, there was insufficient groundwater in B1, B2, B3, B4, B6, B7, B8, B15, B16. Some alternative samples were therefore taken from boreholes B12, B13, B21 and B22 where sufficient water had accumulated in reasonable proximity to the original planned positions.

4.4.9 Samples were taken as far as possible in each borehole. Whereas groundwater levels were recorded at each borehole the depths of groundwater in some boreholes did not accumulate sufficient groundwater. No free products floating on the top of the groundwater were observed but some samples contained suspended material and soil particles. The laboratory was instructed to filter samples accordingly and conduct analysis on the filterable materials.

Soil Sample Handling

4.4.10 Sampling handling was undertaken in accordance with ProPECC PN 3/94 and special care was taken to ensure that cross-contamination between samples did not occur. All samples were uniquely identified. Soil samples were generally taken within an hour of completing each borehole.

4.4.11 Sampling equipment was be thoroughly rinsed with distilled water between taking samples. All sampling equipment was made from neutral materials that could be easily washed between samples and would not affect subsequent laboratory analysis. In view of the expected nature of likely contamination (i.e. hydrocarbons) all samples were immediately chilled following the sampling exercise by placing in insulated boxes with ice packs.

Sample Labelling

4.4.12 All samples from KCIP were given the prefix C. Soil samples from KCIP were given the second letter S. Groundwater samples from KCIP were given the second letter W. Boreholes were identified by number, i.e. B1, B2 etc. The nominal depths 0.5m, 1.5m and 3.0m for a particular borehole were designated S for nearest surface (0.5m) M for middle (1.5m) and B for Bottom (3.0m) and the depth of sample was represented in the label. Thus the nominal middle soil sample from borehole seven would be designated as CS B7 M2.0. Where samples were taken extra to the nominal samples these were designated with an X and the depth of sample was represented in the label. Thus the extra soil sample from borehole nineteen was designated as CS B19 X2.6.

Sampling and Analysis

4.4.13 Samples were tested at a HOKLAS accredited laboratory for the following parameters:

· total petroleum hydrocarbons (TPH); (USEPA 8015)

· polycyclic aromatic compounds (PAC/PAH-16); (USEPA 8270)

· dioxins and furans (PCDD/PCDF); (USEPA 8290 & 1616)

· benzene, toluene, ethlybenzene and xylene (BTEX); (USEPA 8260)

· polychlorinated biphenyls (PCB); (EP066)

· heavy metals (HM, including Ag, As, Cd, Cr, Cu, Hg, Ni, Pb, Zn); (USEPA 6020)

· inorganic parameters pH (EA002) cyanide (EK026) ammonia (EK055) phosphorus (EKO&!A) sulphate (ED041).

[inorganic parameters analysed by HOKLAS accredited in house laboratory methods indicated by prefix E]

4.4.14 In order to establish a comparative level of contamination between boreholes, TPH, PAH, BTEX and HM, inorganic parameters cyanides, sulphates, pH etc., were analysed for all locations. PCBs were analysed in areas where former electrical transforming and power plant was housed. PCDD and PCDF werewas analysed in areas where there was potential for the accumulation of ash products from the incineration process. Assays were conducted in accordance with standard international methods (USEPA or ASTM or equivalent) in line with best international practice.

4.4.15 The rationale for the scope of parameters at each location is described in detail in the CAR. These were agreed with EPD prior to the site investigation, without ruling out the possibility of further sampling locations at a later stage. The overall sampling strategy has provided a framework for the site investigation study in order to determine the overall scale, nature and extent of land contamination.

4.5 Sampling Locations and Analysis of Results

4.5.1 Field investigations conducted by the consultants have taken careful account of the former site activities as far as they can be ascertained and the sampling strategy takes full account of potential locations for contamination. A photographic record of materials from the boreholes and details of the analysis are presented in the CAR. A summary of the results is presented in Tables 4.1 and 4.2. The following section summarises the results of sample analyses. Where indicated in the Tables by <B or >B the quantities of soil contaminants, if present, were less than or greater than the “Dutch B” criteria. Where indicated in the Tables by <C the quantities of soil contaminants, if present, were less than the “Dutch C” criteria. Where indicated in the Tables by <U the quantities of soil contaminants, if present, were less than the “USEPA” criteria (AttachmentAppendix E).

4.5.2 The methodology employed for the investigation was based upon a combination of professional judgement, expertise and qualified assumptions based upon an intricate knowledge of the site layout and past site operations. Plans and suitable diagrams of the site have been made available. This has enabled confirmation by visual identification and sampling and analysis (wherever possible) of the potential locations for contamination. Further detailed descriptions of the site investigations are present in the CAR agreed with EPD.

Table 4.1 Summary of Analytical Results - Soil Samples

SOIL	Method	USEPA 8015	USEPA 8260	USEPA 8270	EP066	USEPA 8290	USEPA 6020	EK026	EK071A	EA002	USEPA
	Analysis Description	TPH	BTEX	PAH	PCB	PCDD / PCDF	METALS	Total Cyanide (combined)	Reactive Phosphorus as P	pH Value @ 25'C	Moisture Content (dried @ 103'C)
	Unit	mg/kg	mg/kg	mg/kg	mg/kg	pg/g	mg/g	mg/kg	mg/kg		%
	Dutch B	1000	0.5 to 5.0	5 to 10	1	n/a	5 to 500	10	200
HK7908-10	CSB1 S0.5	<B	<B	<B	<B		<B	<B	<B	7.4	15.0
HK7908-11	CSB1 M1.5	<B	<B	<B	<B		Pb->B, <C	<B	<B	8.1	15.7
HK7908-12	CSB1 G3.0	<B	<B	<B	<B		<B	<B	<B	6.8	16.1
HK7823-1	CSB2 S2.0	<B	<B	<B	<B		<B	<B	<B	10.6	16.8
HK7823-2	CSB2 M2.2	<B	<B	<B	<B		Pb->B, <C	<B	<B	11.6	17.3
HK7823-3	CSB2 B2.7	<B	<B	<B	<B		Pb, Cu->B, <C	<B	<B	I.S.	5.5
HK7894-1	CSB3 S1.0	<B	<B	<B	<B		<B	<B	<B	7.7	17.2
HK7894-2	CSB3 M2.0	<B	<B	<B	<B		<B	<B	<B	6.0	20.5
HK7894-3	CSB3 G3.0	<B	<B	<B	<B		Pb->B, <C	<B	<B	5.7	21.4
HK7908-7	CSB4 S1.5	<B	<B	<B		<U	Pb->B, <C	<B	<B	9.0	16.1
HK7908-8	CSB4 M2.1	<B	<B	<B		<U	<B	<B	<B	4.6	16.1
HK7908-9	CSB4 G3.0	<B	<B	<B		<U	<B	<B	<B	5.5	19.2
HK7923-1	CSB5 S1.0	<B	<B	<B	<B	<U	<B	<B	<B	7.8	15.8
HK7923-2	CSB5 X1.5	<B	<B	<B	<B	<U	<B	<B	<B	6.8	16.7
HK7923-3	CSB5 M3.0	<B	<B	<B	<B	<U	Pb->B, <C	<B	<B	5.7	18.7
HK7923-4	CSB5 X4.5	<B	<B	<B	<B	<U	<B	<B	<B	4.9	21.0
HK7923-5	CSB5 S6.0	<B	<B	<B	<B	<U	<B	<B	<B	5.3	20.2
HK7842-1	CSB6 S0.4	<B	<B	<B	<B	<U	Pb->B, <C	<B	<B	8.6	15.2
HK7842-2	CSB6 M1.5	<B	<B	<B	<B	<U	<B	<B	<B	8.6	16.1
HK7842-3	CSB6 B3.0	<B	<B	<B	<B	<U	<B	<B	<B	5.6	15.3
HK7864-1	CSB7 S0.9	<B	<B	<B	<B	<U	Pb->B, <C	<B	<B	9.5	16.9
HK7864-2	CSB7 M2.0	<B	<B	<B	<B	<U	<B	<B	<B	5.6	16.4
HK7864-3	CSB7 B3.0	<B	<B	<B	<B	<U	<B	<B	<B	4.9	22.0
HK7870-1	CSB8 S0.4	<B	<B	<B	<B	<U	<B	<B	<B	8.9	16.8
HK7870-2	CSB8 M1.5	<B	<B	<B	<B	<U	<B	<B	<B	8.0	19.0
HK7870-3	CSB8 G3.0	<B	<B	<B	<B	<U	<B	<B	<B	7.5	22.2
HK7842-4	CSB9 S1.0	<B	<B	<B	<B	<U	<B	<B	<B	7.3	15.7
HK7842-5	CSB9 M1.7	<B	<B	<B	<B	<U	<B	<B	<B	8.3	15.7
HK7842-6	CSB9 B3.0	<B	<B	<B	<B	<U	<B	<B	<B	6.7	21.0
HK7864-4	CSB10 S0.8	<B	<B	<B		<U	<B	<B	<B	10.6	11.1
HK7864-5	CSB10 M1.4	<B	<B	<B		<U	<B	<B	<B	11.0	10.1
HK7864-6	CSB10 X3.0	<B	<B	<B		<U	<B	<B	<B	8.3	22.2
HK7864-7	CSB10 G4.0	<B	<B	<B		<U	<B	<B	<B	6.0	23.8
HK7894-4	CSB11 S0.5	<B	<B	<B		<U	<B	<B	<B	8.6	13.9
HK7894-5	CSB11 M1.5	<B	<B	<B		<U	<B	<B	<B	8.7	18.0
HK7894-6	CSB11 X2.0	<B	<B	<B		<U	Pb->B, <C	<B	<B	6.5	20.1
HK7894-7	CSB11 G3.0	<B	<B	<B		<U	Pb->B, <C	<B	<B	5.2	22.6
HK7880-1	CSB12 S1.7	<B	<B	<B	<B		<B	<B	<B	5.0	14.8
HK7880-2	CSB12 M3.0	<B	<B	<B	<B		<B	<B	<B	4.7	24.0
HK7880-3	CSB12 M4.0	<B	<B	<B	<B		<B	<B	<B	5.0	19.3
HK7823-4	CSB13 S2.3	<B	<B	<B	<B		<B	<B	<B	5.1	9.9
HK7823-5	CSB13 M3.0	<B	<B	<B	<B		<B	<B	<B	5.4	25.0
HK7823-6	CSB13 B3.5	<B	<B	<B	<B		<B	<B	<B	5.5	22.4
HK7908-4	CSB14 S1.4	<B	<B	<B			<B	<B	<B	5.1	19.5
HK7908-5	CSB14 M2.5	<B	<B	<B			<B	<B	<B	5.4	21.0
HK7908-6	CSB14 G3.3	<B	<B	<B			<B	<B	<B	5.5	18.3
HK7865-1	CSB15 S0.9	>C	<B	<B	<B		Cu->B, <C	<B	<B	9.0	4.0
HK7865-2	CSB15 M2.4	<B	<B	<B	<B		<B	<B	<B	7.0	19.3
HK7865-3	CSB15 G2.7	<B	<B	<B	<B		<B	<B	<B	6.2	14.1
HK7865-4	CSB16 S0.9	<B	<B	<B	<B		<B	<B	<B	7.8	17.7
HK7865-5	CSB16 M1.5	<B	<B	<B	<B		<B	<B	<B	5.7	20.7
HK7865-6	CSB16 G3.0	<B	<B	<B	<B		<B	<B	<B	5.3	20.3
HK7908-1	CSB17 S1.5	<B	<B	<B			<B	<B	<B	6.6	26.9
HK7908-2	CSB17 M2.5	<B	<B	<B			<B	<B	<B	7.4	18.9
HK7908-3	CSB17 G3.5	<B	<B	<B			<B	<B	<B	5.9	22.0
HK7865-7	CSB18 S0.8	>B, <C	<B	<B		<U	<B	<B	<B	8.7	14.8
HK7865-8	CSB18 M1.5	<B	<B	<B		<U	<B	<B	<B	5.0	15.5
HK7865-9	CSB18 G3.0	<B	<B	<B		<U	<B	<B	<B	5.0	11.9
HK7937-1	CSB19 S1.1	<B	<B	<B	<B	<U	<B	<B	<B	7.4	19.1
HK7937-2	CSB19 M1.9	<B	<B	<B	<B	<U	Cu, Pb->B, <C	<B	<B	7.3	9.2
HK7937-3	CSB19 X2.6	<B	<B	<B	<B	<U	Cu, Pb&Zn->B, <C	<B	<B	7.9	22.3
HK7937-4	CSB19 B3.2	>B, <C	<B	>B, <C	>B, <C	<U	Pb&Cu->C, Zn>B	<B<B	<B	8.3	40.0
HK7943-1	CSB20 S1.6	<B	<B	<B	<B	<U	<B	<B	<B	6.8	17.7
HK7943-2	CSB20 M3.0	<B	<B	<B	<B	<U	Pb&Zn->B, <C, Cu>C	<B	<B	7.4	27.3
HK7943-3	CSB20 B3.8	>B, <C	<B	>B, <C	<B	<U	Pb&Zn->B, <C, Cu>C	<B	<B	7.4	32.3
HK7943-4	CSB21 S2.5	<B	<B	<B	<B	<U	<B	<B	<B	8.0	21.4
HK7943-5	CSB21 M5.0	<B	<B	<B	<B	<U	Pb->B, <C	<B	<B	6.3	22.0
HK7943-6	CSB21 B6.0	<B	<B	<B	<B	<U	<B	<B	<B	5.2	20.1
HK7958-1	CSB22 S1.5	<B	<B	<B	<B	<U	Pb->B, <C	<B	<B		23.8
HK7958-2	CSB22 M2.8	<B	<B	<B	<B	<U	Cu, Pb&Zn->B, <C	<B	<B		14.4
HK7958-3	CSB22 B3.2	<B	<B	<B	<B	<U	Cu, Pb->B, <C	<B	<B		10.2
HK7937-5	CSB23 S1.5	<B	<B	<B		<U	<B	<B	<B	6.3	19.9
HK7937-6	CSB23 B3.0	<B	<B	<B		<U	Pb->B, <C	<B	<B	5.2	18.2
	C22					>U
	C23					>U
	C24					<U
	C25					<U

Table 4.2 Summary of Analytical Results - Groundwater Samples

GROUNDWATER
Analysis Description	TPH	BTEX	PAH	PCB	PCDD / PCDF	METALS	Total Cyanide (combined)	Ammonia as N	Reactive Phosphorus as P	pH Value @ 25'C	Water Depth Approx. 24th May
Unit	ug/L	ug/L	ug/L	ug/L	pg/L	ug/L	mMg/L	mg/L	mg/L		(m, BGL)
Dutch B	200	1 to 20	5 to 10	1	n/a	5 to 500	10	1000	200
CWB1	<B*	<B	IS	IS		IS		IS	IS	7.4	2.3
CWB2	<B*	<B	IS	IS		<B		IS	IS	10.6	2.7
CWB3	IS	IS	IS	IS		IS		IS	IS	7.7	2.8
CWB4	IS	IS	IS	IS	IS	<B		IS	IS	9.0	2.8
CWB5	>C	Toluene >C	<B	<B	IS	<B		<B	<B	7.8	2.8
CWB6	>B, <C	Toluene >C	IS	IS	IS	<B		<B	<B	8.6	2.5
CWB7	<B*	<B	IS	IS	IS	Cd->B, <C		<B	<B	9.5	2.5
CWB8	<B*	Toluene >C	IS	IS	IS	IS		IS	IS	8.9	2.4
CWB9	>C	Toluene >C	<B	<B	<U	<B		>B, <C	<B	7.3	2.4
CWB10	>B, <C	<B	<B	IS	<U	<B		<B	<B	10.6	2.2
CWB11	>C	<B	<B	IS	<U	<B		<B	<B	8.6	2.4
CWB12	>B, <C	<B	<B	IS	<U	<B		<B	<B	5.0	1.9
CWB13	>C	<B	<B	IS	<U	<B		<B	<B	5.1	1.9
CWB14	>B, <C	<B	<B	IS	<U	<B		<B	<B	5.1	2.3
CWB15	<B*	<B	IS	IS	<U	IS		IS	IS	9.0	2.8
CWB16	<B*	<B	IS	IS	IS	<B		IS	IS	7.8	2.8
CWB17	>B, <C	<B	<B	IS	<U	Pb->C		<B	<B	6.6	2.1
CWB18	>B, <C	<B	<B	IS	<U	<B		<B	<B	8.7	1.9
CWB19	>C	<B	<B	<B	<U	<B		<B	<B	7.4	1.9
CWB20	>C	<B	IS	<B	<U	<B		<B	<B	6.8	1.7
CWB21	>B, <C	<B	<B	<B	<U	<B		<B	<B	8.0	1.9
CWB22	>C	<B	<B	<B	<U	Zn, Cu->B, <C		>C	>C		2.3
CWB23	<B*	<B	IS	IS	IS	Zn->B, <C		IS	IS	6.3	3

IS = Insufficient Sample * sufficient sample to test c6 to c9 fraction only

4.6 Contamination Assessment

Local Contamination Levels

4.6.1 The presence of soil contaminants does not necessarily imply that there are any implications for the demolition procedures or public health. However, the presence of contaminants in the soil could pose potential risks to workers and site users. In terms of the demolition activities no excavation is required and potential hazards to demolition workers and public health due to the disturbance of contaminants are minimal. The purpose of this section of the CAR/RAP isof the CAR/RAP is to allow the consultants to draw attention to those isolated samples where contamination has been identified and assess if and when remedial action is required. , or if in some cases confirmatory sampling should be considered.

Inorganic Parameters

4.6.2 Cyanide was not detectable in any locations except for B19 lowerr samples at 2.6m and 2.6m and 3.2m. The total combined cyanide levels were below where it was present at above the “Dutch B” criterion. Other inorganic parameters were present at below the “Dutch B” criteria. Clean up at B19 is not warranted to remove such incidences of contamination.

Heavy Metals

4.6.3 In several locations the heavy metals Pb, Zn and Cu have been detected above the “Dutch B” criterion. In accordance with Government policy, the presence of metals at these concentrations requires remedial action. Where Pb, Zn or Cu were detected at above the “Dutch B” level at B1, B2, B3, B4, B5, B6, B11, B15, B19, B20, B21, B22 and B23 remedial action is required. (It is noted that TPH was also detected at above the “Dutch B” level at B15, B18, B19 and B20 and remedial action required at these three locations is determined by the presence of both types of contaminants). Clean up is warranted to remove such incidences of contamination. Reassurance / confirmatory sampling will be required after initial clean up to determine the effectiveness of the remedial action and the extent of any additional areas for remedial action.

Total Petroleum Hydrocarbons (TPH)

4.6.4 Whereas there is no “Dutch B” criterion for TPH contaminants, TPH is a general indication for the presence of hydrocarbons and the “Dutch” criteria for mineral oil are usually referred to. In some locations (B15, B18, B19, B20) TPH has been detected at above this criterion. Where TPH was detected at above the “Dutch B” level at B18, B19 and B20 in each case the concentrations were below the “Dutch C” level. The presence of TPH may be due to coal type particulates. Such particles could be clearly identified in the samples of the soil from B18, B19 and B20. The TPH in B15 was due to a slug of bitumen like oily material. The presence of toluene in some groundwater samples with higher TPH could also be due to leaching of coal tar type compounds.

4.6.5 B15, B18, B19 and B20 are scheduled for remedial action based on metal contamination, however an alternative approach. encompassing Tthe hydrocarbon contaminants at B15, B18, B19 and B20 will also be required testing and disposal at landfill for these locations (Table 4.3). Reassurance / confirmatory sampling will be required after clean up to determine the effectiveness of the remedial action and the extent of any additional areas for remedial action.

4.6.6 The presence of TPH in groundwater samples from B11 and B13 could be due to downward migration of hydrocarbons from surface contamination. However, the presence of coal type black particles in these locations and those from adjacent borehole B9, B11, B13, B19, B20 and B22 also suggest the presence of TPH may be due to coal type contaminants in the original fill material. However migration of contaminants from the adjacent GDBL site is also a possible cause of contamination for B19, B20 and B22.

Polyaromatic Hydrocarbons (Polynuclear Aromatics, PAH)

4.6.7 A selection of 15 PAH compounds including those on the “Dutch ” list were analysed in all samples. PAH was not detectable in most borehole samples. Where encountered, at B19 3.2m and B20 3.8m, the concentrations are generally below the “Dutch B” levels for individual PAHs. However benzpyrene is present at the “Dutch B” levels in B19 and B20 and total PAH is above the Dutch B criterion requiring clean up in B19 and B20 in the deepest samples. The alternative approach encompassing the hydrocarbon contaminants (see TPH above) will be applied to these locations due to the TPH contamination, which will also deal wit the PAH.

Benzene , Toluene, Ethylbenzene, Xylene (BTEX)

4.6.8 BTEX included on the “Dutch ” list were analysed in all samples. The limit of detection was below the “Dutch B criterion for such contaminants. BTEX was not detectable in any borehole samples. The presence of Toluene in groundwater from B5, B6 and B9 appears to be associated with some samples which have higher TPH levels and may also possibly be associated with hydrocarbon type contaminants in the original fill material.

Polychlorinated Biphenyl (PCB)

4.6.9 PCB is included on the “Dutch ” list. Total PCB was analysed in some samples. The limit of detection was below the “Dutch B criterion for such contaminants. PCB was only detectable in three borehole samples nearest the GDBL. Atat the cast of the site. B19 X2.6, B20 M3.0m and B20 3.8m, the concentrations are below the “Dutch B” levels. No clean up is warranted to remove these isolated incidences of contaminants where they are present in such concentrations. At B19 B3.2m the concentration is above the “Dutch B” level. Where encountered at B19 3.2m the concentration of PCB is above the “Dutch B” levels but well below the “Dutch C” criterion. Clean up is warranted on grounds of PCB (as well as TPH, PAH and heavy metal) contamination.

pH

4.6.10 The range of pH values encountered was from alkaline (11.6) to acid (4.6). Given the range of soil types sandy to clay and fill materials encountered such a range of pH is not exceptional and no significance in terms of contamination is attached to this range of pH.

Dioxins and Furans (PCDD & PCDF)

4.6.11 A selection of 25 PCDD and PCDF congeners were analysed in selected soil samples. The concentrations were below the USA criterion for such contaminants in all the soil samples. No clean up of soils is warranted to remove PCDD and PCDF contaminants where they are present in such concentrations.

4.6.12 Significant concentrations of PCDD and PCDF congeners were found in the ash deposits remaining on the walls in some locations at C22 and C23. The location and amounts of PCCD and PCDF contaminated ash to be cleared up prior to demolition have been estimated. No PCDD/PCDF were detected at above the USEPA criterion at any other locations in samples near the surface. Remedial action will be required to clean up these materials prior to the demolition as PCDD/PCDF were above the USEPA criterion in some of the samples. Prior to the demolition it is recommended that potentially contaminated ash materials within 5m of the ash bunker wall be cleaned up. Special precautions will be required which are dealt with under the RAP section of this report.

Overall Contamination Levels

Soil

4.6.13 Almost all samples have indicated that the quantities of soil contaminants, if present, are well below the “Dutch B” criteria. Where contaminants have been detected above the “Dutch B” criteria, concentrations are generally below the “Dutch C” criteria. Therefore whereas overall the site may not be considered to be uncontaminated from previous activities, contamination is not widespread. Soil contamination with heavy metals Pb, Zn or Cu has been formed in many of the 23 boreholes and based on current information remedial action at B1, B2, B3, B4, B5, B6, B7, B11, B15, B19, B20, B21, B22 and B23 is required for HM contamination. Additionally alternative methods will be required to deal with hydrocarbon contamination at B15, B18, B19 and B20. Reassurance / confirmatory sampling will be required (see RAP) after initial clean up to determine the effectiveness of the remedial action and the extent of any additional areas for remedial action.

Ash Deposits on Walls

4.6.14 PCDD/PCDF were above the USEPA criterion in C22 and C23 and below the USEPA criterion in C24 and C25. Remedial action will be required to clean up these materials prior to the demolition as PCDD/PCDF were above the USEPA criterion in some of the samples. Prior to the demolition it is recommended that all potentially contaminated ash materials be cleaned up and in order to take a precautionary approach all ash materials within 5m of the ash bunker wall should be cleaned up.

Groundwater

4.6.15 Groundwater samples have indicated that the quantities of contaminants, if present, are generally well below the “Dutch B” criteria. However Aas groundwater is not utilised sed in Hong Kong as a potable resource in Hong Kong the Dutch criteria are not generally applicable. Where contaminants have been detected above the “Dutch B” criteria, concentrations are generally below the “Dutch C” criteria with the exception of toluene in some samples. Generally with respect to groundwater the site is considered to have limited contamination from previous activities. Exceptions are, the presence of HM Pb in groundwater at B17, the presence of Toluene in groundwater from B5, B6, B8 and B9 and the presence of TPH in samples from B5, B9, B11, B13, B19, B20 and B22. Observations did not indicate any strong evidence that contaminated leachate from the adjacent landfill was entering the site. In any locations where water from underground is contaminated, rRemediation on the l action is required for the soils in these locations and such action soil should also stabilise and immobilise any possible leachate entering the groundwater. However the possibility of leachate entering the site in groundwater cannot be ruled out and the contractor will be required to make provisions to treat surplus groundwater or leachate to reduce chemical concentrations in order to comply with the standards for effluents discharged into the inshore waters of Victoria Harbour WCZ under the TM. It is noted that groundwater is not utilised as a potable resource in Hong Kong (see Ssection 8).

Conclusion

4.6.16 Contamination Assessment, based on the results of a detailed Site Investigation, including the collection of sub-surface samples and chemical analyses, has indicated that the levels of contamination are generally below the criteria that indicate gross pollution of the site. However there is a requirement for remedial action as some localised areas of ground contamination have been identified under the KCIP site. Where contaminants have been detected above the “Dutch B” criteria concentrations in many locations are not indicative of heavy pollution but still require clean-up in line with Government policy. In all but a few cases the contamination is persistent and immobile (e.g. heavy metals). The entire site is currently paved in thick concrete and viable exposure pathways are minimal. In the context of the current EIA study, it is considered that the possibilities for contact with ground contaminants during the demolition of KCIP are relatively low, provided appropriate precautions are implemented. This is because ground excavations will not be necessary. Contaminants are however present on some walls of the KCIP and these must be cleaned up under controlled conditions prior to the demolition. Possibilities for workers to have contact with ground contaminants during the demolition of KCIP can be controlled by implementation of appropriate safety precautions that have been recommended (AttachmentAppendix D).

4.6.17 The KCIP site is currently zoned as “G/IC” (with no identified long term use of the area after demolition) the future land use is unlikely to be residential. The extent of sampling and the number and location of boreholes is adequate and representative to determine the extent of potential contamination due to past site activities. At this stage no further intrusive underground soil sampling or subsequent testing is warranted which would have implications for the EIA for demolition of the KCIP. However some remedial action is required and it is also required that ground conditions are confirmed after remedial action has been completed in certain locations prior to the release of the site for its end-use.

4.7 Remediation Action Plan

Extent of Contamination

4.7.1 Whereas overall the site may not be considered to be uncontaminated from previous activities, contamination is not widespread. Overall the site is not grossly contaminated from previous activities and at this stage no further intrusive underground soil sampling or subsequent testing is scheduled. Where present the concentrations of contaminants encountered do not have implications for the demolition of the KCIP as no excavation is necessary for the demolition.

4.7.2 Clean up of several areas is warranted to remove such contaminants as heavy metals and hydrocarbons identified in the preceding contamination assessment. Reassurance confirmatory sampling is required for soils after the excavation of contaminated material demolition to determine the extent of any further excavation and remediation required. No further site investigation is required however, reassurance confirmatory sampling is required for soils after the excavation of contaminated material or to determine the extent of any further excavation and remediation required. Following the completion of the remediation works it is recommended that a remediation report is prepared for submission and approval by EPD to demonstrate that the remediation work has been undertaken according to the agreed methodology and been shown to be adequate.

Remediation Options for Soils

Heavy Metal Contamination

4.7.3 Excavation and landfilling is often seen as the most convenient method, however, disposal at landfill is only to be considered as a last resort. In this case most of the contamination is associated with heavy metals and in-situ or on-site immobilisation or stabilisation is applied to land contaminated with heavy metals (ProPECC PN3/94).

4.7.4 In the immobilisation process a variety of reagents (cement / lime / silicate) can be applied to fix the contamination chemically and isolate the contamination. In this case it is envisaged that the process would involve excavation and mixing the excavated material with cement. The solidified soil and cement mix would be returned to the ground in small blocks, returning uncontaminated extracted material around the blocks in the ground and compacting. The proportions of cement to soil should be determined after field trials with different mixes of soil to cement subjected to toxicity characteristic leachate procedures (TCLP, ASTMS Method 1311) to determine the most appropriate mix.

4.7.5 Remediation for heavy metals will be required at fourteen locations centred on the borehole locations. The process will involve the excavation of the covering cement and any covering materials that are not contaminated (as shown by previous sampling). Contaminated materials at specific depths within 5m of the borehole and between specified depths will then be removed. 10m x 10m pits will therefore be excavated to the requisite depths. It is required that reassurance sampling be carried out at the extremities of the excavated hole to test for any surplus contamination (refer Table 4.3). Five samples would generally be taken at positions N, S, E, W and at the base of excavated hole (Figure 4.2). Soils samples would be analysed for the contaminating metals. If samples contain contaminants above the Dutch B levels, further excavation is required either at the sides or at the bottom of the borehole as appropriate until uncontaminated material is identified.

4.7.6 Contaminated materials will be removed, stockpiled separately from the uncontaminated materials and mixed with the appropriate amount of cement for immobilisation. The mixture will be cast in small blocks. The blocks can than be placed / stacked in the holes or broken up and compacted back into the holes. Uncontaminated material can then be used to fill around the blocks and compacted to level the surface.

Other Contaminants

4.7.7 Whereas some references indicate that such immobilisation techniques may also be likely to stabilise any associated hydrocarbons that are present such a technique would need to be proven for acceptability in Hong Kong. In this case the quantities of contaminated soil is small (a few hundred cubic metres) and disposal at landfill will be a suitable option for materials from the top metre of soil materials below the concrete cover at B15 and B18 and material from below 2.6m at B19 and B20. The material will be disposed of at landfill rather than returned to the holes on site because of the hydrocarbon contamination.

4.7.8 Prior to disposal the leaching characteristics of the materials and suitability for landfilling shall be determined after samples have been subjected to toxicity characteristic leachate procedures (TCLP, ASTMS Method 1311). If the materials pass the tests and are suitable for landfilling they can be transported to the designated landfill for disposal. If the materials fail the tests and are unsuitable for landfilling they must be pre-treated prior to being transported to the designated landfill for disposal. In this case the details of the remediation vis a vis the treatments to be applied at each location will be the same as for the heavy metals. Reassurance sampling will also take place. The details of the remediation treatments to be applied at each location will be determined after TCLP testing. Provisions for reassurance / confirmatory sampling have been made (Table 4.3).

4.7.9 Table 4.3 indicates where remedial action will be required, where reassurance/confirmatory sampling is warranted and summarises the locations requiring clean up based on the available information. In order to make sure that all contaminated material is excavated a margin of about 0.3 to 0.5 metre is allowed above and below the shallowest and deepest contamination detected.

4.7.10 Whereas it is not possible to confirm the total amounts of waste requiring treatment it is helpful to gauge the scale of the works required. Assuming that reassurance / confirmatory sampling did not identify any additional contaminated areas, a broad-brush estimate of the amount of material for treatment within 5m of the boreholes has been made (Table 4.3).

Management of Contaminated Soil Material

4.7.11 Although ground conditions on the site are contaminated with metals and some organic compounds, in isolated locations, atat this stage the only opportunity for human exposure to any of the contamination on site will be if the materials are excavated.

4.7.12 For this site and any potential redevelopment, the preferred approach with least environmental impact, is to cause minimal disturbance to the ground conditions, immobilise the contaminated soils where necessary and make provisions for the protection of workers. Where this is not appropriate the disposal of some small amount of material to landfill may be a more suitable remedial option.

Volume of Soil for Immobilisation

4.7.13 The volume of soil to be treated on site has been estimated by assuming making a broad brush estimate based on depths to which materials >Dutch B are identified by sampling. The estimated total of about 1750m³ is preliminary and assumes that all material within 5m (10m x 10m square hole) at the contaminated depths would be treated. This excludes the 450m³ for disposal at landfill. The material is not disposed of off site and therefore off site effects are minimised. However it is possible that reassurance sampling at the periphery and base of the excavations will identify further contaminated materials at a later stage, however it is not possible to predict the extent of this contamination based on current information.

Volume of Soil to Landfill

4.7.14 Materials contaminated with hydrocarbons will be directed to landfill. A volume of about 450m³ contaminated with hydrocarbons would be directed to landfill. Again this estimate is preliminary and assumes that all material within 5m (10m x 10m square hole) at the contaminated depths would be treated. In this case the material is disposed off- site, however the quantities are small perhaps resulting in a few tens of lorry loads and therefore off- site effects are not expected to cause any in-surmountable environmental problems. The precise volume of hydrocarbon contaminated waste is also difficult to determine. However, the hydrocarbon contaminated soil appears to be confined to the lower depths at one end of the site. Whereas it is possible that reassurance sampling at the periphery and base of the excavations will identify further contaminated materials at a later stage, it is not possible to predict the extent of any additional contamination based on current information.

Protection of Site Workers during excavation and treatment of soils

4.7.11 General site safety provisions incorporate some basic practices such as the provision of safety boots, hard hat, overalls, gloves and eye protection. In addition, dust masks shall be made available and sufficient first aid facilities and procedures and appropriate washing amenities. It is important to avoid skin contact, ingestion and inhalation of contaminated materials, however this would not normally be a significant risk provided basic personal protective equipment is provided. In addition to statutory occupational safety requirements site staff shall be given adequate training and instruction specific to the potential hazards in the work place, their health and safety responsibilities and safe working practice including basic personal hygiene, which is important on contaminated sites.

Table 4.3 Actions Required Post Demolition

Borehole	Action Required	Remove concrete surface and clear uncontaminated surface material and stockpile	Proposed depth of Material for Removal or Treatment	Remedial Action *	Estimate quantity of contaminated material for Treatment (m^3 , #)	Reassurance / Cconfirmatory Sampling	Sampling Strategy
B1	Yes	Down to 1m depth	1m to 2m	Immobilisation *	100	Yes, determine extent of HM (Pb) contamination at edge and base of hole.*	5 samples 5m N, S, E, W and base of borehole,
B2	Yes	Down to 2m depth	2m to 3m	Immobilisation *	100	Yes, determine extent of HM (Pb, Cu) contamination at edge and base of hole.*	5 samples 5m N, S, E, W and base of borehole,
B3	Yes	Down to 2m depth	2m to 3.5m	Immobilisation *	150	Yes, determine extent of HM (Pb) contamination at edge and base of hole.*	5 samples 5m N, S, E, W and base of borehole,
B4	Yes	Concrete down to 1.5m depth	Below concrete down to 2m	Immobilisation *	50	Yes, determine extent of HM (Pb) contamination at edge and base of hole.*	5 samples 5m N, S, E, W and base of borehole,
B5	Yes	Down to 1.5m depth	1.5m to 3.5m	Immobilisation *	200	Yes, determine extent of HM (Pb) contamination at edge and base of hole.*	5 samples 5m N, S, E, W and base of borehole,
B6	Yes	Concrete down to 0.4m depth	Below concrete down to 1.4m	Immobilisation *	100	Yes, determine extent of HM (Pb) contamination at edge and base of hole.*	5 samples 5m N, S, E, W and base of borehole,
B7	Yes	Concrete down to 0.9m depth	Below concrete to 1.9m	Immobilisation *	100	Yes, determine extent of HM (Pb) contamination at edge and base of hole.*	5 samples 5m N, S, E, W and base of borehole,
B8	No Clean Up	N/A	N/A	N/A	N/A	N/A	N/A
B9	No Clean Up	N/A	N/A	N/A	N/A	N/A	N/A
B10	No Clean Up	N/A	N/A	N/A	N/A	N/A	N/A
B11	Yes	Down to 1.5m depth	1.5m to 3.5m	Immobilisation *	200	Yes, determine extent of HM (Pb) contamination at edge and base of hole.*	5 samples 5m N, S, E, W and base of borehole,
B12	No Clean Up	N/A	N/A	N/A	N/A	N/A	N/A
B13	No Clean Up	N/A	N/A	N/A	N/A	N/A	N/A
B14	No Clean Up	N/A	N/A	N/A	N/A	N/A	N/A
B15	Yes $$	Excavate concrete down to 0.9m. (TPH contamination as bolus of tarry bitumen at 0.9m (only).	0.91.0m to 2.0m	TCLP test followed by removal of 1m to 2m landfill. Immobilisation if necessary **. @	1100	Yes, determine extent of HM (Cu) and TPH) contamination. *. $$	5 samples 5m N, S, E, W and base of borehole,
B16	No Clean Up	N/A	N/A	N/A	N/A	N/A	N/A
B17	No Clean Up	N/A	N/A	N/A	N/A	N/A	N/A
B18	Yes	Excavate concrete down to 0.6m depth	Below concrete (0.6m) down to 1.6m	TCLP test followed by removal of 0.6m to 1.6m to landfill, @.	100	Yes, determine extent of TPH contamination at edge and base of hole.*	5 samples 5m N, S, E, W and base of borehole,
B19 (surface)	No Clean Up	Concrete down to 1.6m depth	N/A	N/A	N/A	N/A	N/A
B19 (middle)	Yes	N/A	1.6m down to 2.6m	Immobilisation.	100	Yes, determine extent of HM (Cu, Zn and Pb) contamination at edge and base of hole.*	5 samples 5m N, S, E ,W of borehole,
B19 (bottom)	Yes	N/A	2.6m down to rockhead (say 3.2m)	TCLP test followed by removal of 2.6m to 3.6m landfill. Immobilisation if necessary **, @.	<100	Yes, determine extent of HM (Pb, Zn and Cu) PCB, PAH and TPH and TPH) contamination at edge and base of hole.*	5 samples 5m N, S, E, W and base of borehole,
B20	No clean Up	Down to 2.5m depth	N/A	N/A	N/A	N/A	N/A
B20	Yes	N/A	2.5m to 4.0m (or rockhead)	TCLP test followed by removal of 2.5m to 4m to landfill. Immobilisation if necessary* *, @	150	Yes, determine extent of HM (Cu, Pb, Zn) PAH and TPH contamination at edge and base of hole.*	5 samples 5m N, S, E, W and base of borehole,
B21 (top)	No Clean Up	Concrete down to 2.5m Remove soil to 4.0m depth	Assume surface to 4.0m not contaminated.	N/A	N/A	N/A	N/A
B21 (bottom)	Yes	N/A	4.0m to 6.0m contaminated	Immobilisation *	200	Yes, determine extent of HM (Pb) contamination at edge and base of hole.*	5 samples 5m N & S, 2m E & W and base of borehole.
B22	Yes	Concrete down to 1.5m depth	Immediately below concrete at 1.5m down to 4.0m (or rockhead)	Immobilisation*	25020	Yes, determine extent of HM (Pb, Cu and Zn) contamination at edge and base of excavated hole.*	5 samples 5m N, S, E ,W and base of borehole
B23	Yes	Down to 1.5m depth	Immediately below concrete at 1.5m to 3.5m contaminated.	Immobilisation*	200	Yes, determine extent of HM (Pb) contamination at edge and base of hole.*	5 samples 5m N, S, E, W and base of borehole,
Refuse and Ash Bunkers	Yes	N/A	N/A	Landfill disposal	To be determined after inspection of bunkers	Examine bunker refuse prior to demolition	Consider analysis depending on bunker contents
Main Hall Ash Bunker Wall	Yes	N/A		Remove ash under controlled conditions up to 5m up wall. Landfill disposal to meet EPD criteria.	Assume materials within 5m of ground contaminated	Visual inspection of walls to ensure all visible dust and debris removed.	-
Main Hall Floors	Yes	N/A	-	Remove ash under controlled conditions up to 5m from wall. Landfill disposal to meet EPD criteria.	Assume materials within 5m of wall contaminated.	Visual inspection of floor within 5m of wall to ensure all visible dust and debris removed.	-
Chimney	Reassurance sampling only	N/A				Review requirements after demolition and confirmatory sampling.	-

* If contamination confirmed by reassurance sampling extract a further 1.0m into the soil, immobilise and resample.

** TCLP test for all metals identified in Table E1 in EPD Contaminated Sites Investigation and Remediation Guidance Notes

$$ TPH Contamination isolated to bolus of tarry bitumen found only at one depth. Isolated contaminant.

# According to the quantity of contaminated material estimated for each borehole location, the total quantity of contaminated soil should be about 2200m^3. .

About 1750m^3. of the total volume is estimated to require treatment on site by immobilisation (Broad brush estimate based on depths to which materials >Dutch B are identified by current round of sampling and all material within 5m (10m x 10m square hole) to that depth (rounded up to nearest 10m³.)

@ Broad brush estimate of materials to be transferred to landfill (rounded up to nearest 10m³). (Total about 450m³, broad brush estimate as # , requiring confirmation).

$$ TPH Contamination isolated to bolus of tarry bitumen found only at one depth. Isolated contaminant.

# Broad-brush estimate based on depths to which materials > Dutch B are identified by current round of sampling and all material within a 5m radius to that depth
(rounded up to nearest 10m³. (Total 2,200m³, broad brush estimate only, requiring confirmation).

According to the quantity of contaminated material estimated for each borehole location, the total quantity of contaminated soil should be about 2200200m^3. .

About 1750m^3. of the total volume is estimated to require treatment on site by immobilisation (

Broad brush estimate based on depths to which materials >Dutch B are identified by current round of sampling and all material within 5m (10m x 10m square hole) to that depth

(rounded up to nearest 10m³. ) (Total 2200 m^3., broad brush estimate only, requiring confirmation).

@ Broad brush estimate of materials to be transferred to landfill (rounded up to nearest 10m³. (Total about 45000 m^3., , broad brush estimate as # ,only, requiring confirmation).

Management of Contaminated Soil Material

1.1.1Although ground conditions on the site are contaminated with metals and some organic compounds in isolated locations, at this stage the only opportunity for human exposure to any of the contamination on site will be if the materials are excavated.

1.1.1For this site and any potential redevelopment, the preferred approach with least environmental impact, is to cause minimal disturbance to the ground conditions, immobilise the contaminated soils where necessary and make provisions for the protection of workers. Where this is not appropriate the disposal of some small amount of material to landfill may be a more suitable remedial option.

Volume of Soil for Immobilisation

1.1.1The volume of soil to be treated on site has been estimated by assuming making a broad brush estimate based on depths to which materials >Dutch B are identified by current round of sampling. The estimated total of 2200 m³ is preliminary and assumes that all material within 5m (10m x 10m square hole) at the contaminated depths would be treated. The material is not disposed of off site and therefore off site effects are minimised. However it is possible that reassurance sampling at the periphery and base of the excavations will identify further contaminated materials at a later stage, however it is not possible to predict the extent of this contamination based on current information.

Volume of Soil to Landfill

1.1.1Materials contaminated with hydrocarbons will be directed to landfill. Again, the estimated volume of 400 m³ is preliminary and assumes that all material within 5m (10m x 10m square hole) at the contaminated depths would be treated. In this case the material is disposed off site, however the quantities are small perhaps resulting in a few tens of lorry loads and therefore off site effects are not expected to cause any in-surmountable environmental problems. The precise volume of hydrocarbon contaminated waste is also difficult to determine. However, the hydrocarbon contaminated soil appears to be confined to the lower depths at one end of the site. Whereas it is possible that reassurance sampling at the periphery and base of the excavations will identify further contaminated materials at a later stage, it is not possible to predict the extent of any additional contamination based on current information.

Protection of Site Workers during excavation and treatment of soils

1.1.1General site safety provisions incorporates some basic practices such as the provision of safety boots, hard hat, overalls, gloves and eye protection. In addition, dust masks shall be made available and sufficient first aid facilities and procedures and appropriate washing amenities. It is important to avoid skin contact, ingestion and inhalation of contaminated materials, however this would not normally be a significant risk provided basic personal protective equipment is provided. In addition to statutory occupational safety requirements site staff shall be given adequate training and instruction specific to the potential hazards in the work place, their health and safety responsibilities and safe working practice including basic personal hygiene, which is important on contaminated sites.

1.1.1Given the potential for hydrocarbons (TPH) in the soil and groundwater skin contact shall be avoided. Prolonged exposure (i.e. skin contact) can potentially result in dry skin, irritation and allergic dermatitis although these effects would not normally cause acute reactions at the concentrations encountered so far encountered at this site. Exposure to dusty material shall be avoided. Dust shall be controlled at source by damping techniques and operatives shall be protected by the use of dust masks.

4.7.16 TGiven the potential for hydrocarbons (TPH) in the soil and groundwater, skin contact shall be avoided. Prolonged exposure (i.e. skin contact) can potentially result in dry skin, irritation and allergic dermatitis although these effects would not normally cause acute reactions at the concentrations encountered so far encountered at this site. Exposure to dusty material shall be avoided. Dust shall be controlled at source by damping techniques and operatives shall be protected by the use of dust masks.

4.7.17 To ensure that the health and safety measures outlined above are actually implemented on-site, specific clauses can be incorporated into the contract documents, and the proponent shall provide and EM&A team with experienced staff on similar sites in Hong Kong to supervise/audit the demolition. This supervision will ensure that the specific contractual clauses are followed and that health and safety on the site is given a high priority.

Procedures for Management of Contaminated Ash Material

4.7.18 There are several issues with regard to the remaining ash deposits. After on site The treatment the ash material will not be classified as a chemical waste under the Waste Disposal (Chemical Waste) (General) Regulation. However and arrangements must be made for the treatment, removal, packaging, storage and transportation, prior to disposal in line with statutory requirements and codes of practice.

4.7.19 The methods for treatment of ash deposits must ensure that all routine construction site safety procedures would apply as well as statutory requirements in line with the Occupational Safety and Health Ordinance and Factories and Industrial Undertakings Ordinance. Due to the difficulties in establishing permanent and effective engineering controls, for the protection of workers are is likely to be at the worker level. A safe system of work must be provided, training and suitable personal protective equipment should be provided as well as hygienic decontamination facilities. Nevertheless it is recommended that the methods to be adopted by the contractor for disposal of the ash material be agreed with Labour Department and EPD.

4.7.20 The project proponent (CED) has indicated that sufficient time will be allocated for the proper abatement of all such ash materials. CED will ensure the implications of dust containing PCDD and PCDF on air quality and workers health during the clean up work are mitigated. It is recommended that a suitably experienced consultant with experience in the abatement of chemical wastes will be appointed prior to the appointment of contractors with experience in the abatement of chemical wastes in order to assist with the evaluation of the information and prepare an abatement plan for the ash materials., Hhowever there are no insurmountable problems. Such a plan shall be submitted to EPD and the Department of Labour to establish an acceptable and safe method for these potentially hazardous materials. The abatement plan should identify the method of abatement, the performance criteria for the protection of workers and the environment and any emergency procedures and contingency measures required. The plan should also quantify the amount of material that will require removal.

Volume of Ash for Disposal

4.7.21 At this stage the precise volume of ash waste (containing PCDD and PCDF) is difficult to determine. However the encrusted ash appears to be confined to the wall between the main incinerator hall and the ash bunker. Assuming some ash may have been dislodged from the wall and is present on the floor, it is recommended that all ash materials:

· on the walls up to 5m between the main incinerator hall and the ash bunker; and

· on the floor within 5m of the walls,

be considered as contaminated with PCDD/PCDF.

4.7.22 Such deposits are present on only parts of the walls and floor. It is estimated that the total ash on within 5m of the wall would amount to less than 20m³. Prior to clean up reassurance sampling of floor deposits at 5m from the wall shall be conducted to confirm that surface contaminants containing PCDD and PCDF have been targeted. If the remaining contaminated ash deposits are in fact confined to the walls between the incinerator main hall and the ash bunker, as indicated by the samples C22 to C25, the total volume would be in the order of 15 to 20m³.

4.7.23 Information so far indicates that the contaminated ash is not present elsewhere as indicated by the topmost samples for the soil contamination assessment. Sampling in the main hall shall take place prior to the appointment of contractors for the demolition such that sufficient time will be allocated for the abatement and the development of the abatement method, safety procedures, storage and disposal methods to the satisfaction of EPD and the Department of Labour.

Supervision of the Works

4.7.24 It may be necessary for Tthe appointed consultant to shall conduct a supplementary investigation of the ash. In this case a supplementary submission will be required to cover any contaminated ash found in the KCIP. The consultant must also check that the proposed methods of the appointed contractors conform to the requirements of agreed with EPD and the Department of Labour. It will also necessary for the appointed consultant, on behalf of the project proponent, to inform EPD / Labour Department of any revisions to the proposed methods and the exact locations of the potentially contaminated works areas etc. It is recommended that a reasonable period of notice be made to EPD and Labour Department prior to commencement of works (say 14 to 21 days) in order that the details of the abatement works can be confirmed.

4.7.25 Consultants shall supervise the ash clean up works and a HOKLAS accredited laboratory should be appointed to be responsible for sample analysis and also airborne dust monitoring during the abatement works under the direction of the consultant. The HOKLAS laboratory will be determined by CED after a routine tendering procedure at a later stage. At this stage it is not possible to provide detailed information on the sequencing of the removal works as these details will to some extent depend on the proposals agreed with EPD and the Department of Labour. However in order to advance the abatement planning as far as possible at this stage, the basic approach is presented in the following sections.

Disposal of Ash Wastes

4.7.26 The ash waste contains a considerable amount of dioxin and in its untreated state would be is classified as a chemical waste under the Waste Disposal (Chemical Waste) (General ) Regulation. Due to the unusual nature of this waste EPD and the consultants discussed the options for the disposal. Based on the consultants’ experience and professional judgement a proposal to immobilise the dioxin contaminated material for off-site disposal at landfill was put forward. However it was also recognised that this was something of an unusual disposal problem and not one that was routinely encountered in Hong Kong.

4.7.27 Subsequent to the meeting on 2^nd March 2001, a literature search did not identify any standard international practice on the disposal of dioxin contaminated ash although specific examples of disposal of dioxin contaminated ash/soil from incinerators were identified. In some cases, where no known permitted disposal facilities for accepting dioxin waste could be identified, the waste has been handled by excavation and encapsulation (e.g. in an on site concrete vault) until such time as other disposal options become available. In one case where dioxin concentrations were as high as 5.580ppb temporary encapsulation in a concrete vault and clay encapsulation of some 200m³of dioxin contaminated soil and ash was implemented. Subsequently these contaminated materials were excavated, loaded on to trucks and transported to the disposal facility for incineration. Surrounding soils were tested for residual contamination and the concrete vault disposed of at landfill (Appendix E). In other cases off site disposal to landfill with the installation of capping materials have been chosen.

4.7.28 At KCIP the amount of dioxin waste is much smaller and the concentrations are from 3ppb to 22ppb than in the example. Therefore action planning for similar quantities (up to 20m³ at KCIP) could consider that comparable methods such as encapsulation and landfill disposal of dioxin contaminated rubble and ash would be effective. With these factors in mind options for the disposal of such waste from the subject site, that were discussed at the meeting on March 2^nd 2001, and subsequently through liaison, included disposal via the Chemical Waste Treatment Centre (CWTC), on site immobilisation or disposal at landfill.

1.1.1 didididhad have Options for the disposal of such waste include disposal via the Chemical Waste Treatment Centre (CWTC), on site immobilisation or disposal at landfill.

4.7.29 Immobilisation and burial on site could be considered. This would involve mixing with concrete under controlled conditions and subsequent TCLP testing to determine that the dioxins had been stabilised. In this condition the ash would not be classified as a chemical waste. , TCLP would be carried out prior to placement underground, presumably in one of the excavated holes from other contaminated locations. In this case such an approach would place the contamination (albeit immobilised) underground, as opposed to the current overground location. Given the possibility of other alternative treatment (such as at the CWTC) this the disposal element of this option was not therefore not considered appropriate.

4.7.30 It is expected that the waste will be stabilised by cement and pulverised fly ash at the CWTC and tested using TCLP. The stabilised waste will then be transported to SENT Landfill for disposal. In this case, there will be no saving in landfill space. It has been confirmed that the Chemical Waste Treatment Centre (CWTC) is capable of treating the waste and all chemical waste producers in Hong Kong can request a collection service from the CWTC, on condition that the waste is capable of treatment. It is expected that in this case the waste would be stabilised by cement and pulverised fly ash at the CWTC and tested using TCLP. The stabilised waste will would then be transported to SENT Landfill for disposal. In this case, the untreated material would need to be transported to the CWTC and there will be no saving in landfill space. However oOwing to the limited capacity of the CWTC treatment facilities some time would be required for the treatment of the ash waste. Arrangements could be made with the Chemical Waste Treatment Centre (CWTC) for the disposal of part or all of this waste. Due to the relatively manageable amount of waste (in this case up to 20m³) it could be collected ready for transportation aand chemical treatment at the CWTC under controlled conditions.

4.7.31 Alternatively the waste could be immobilised on site , collected, and transported for landfilling under controlled conditions without recourse to the CWTC. In this case agreement must be gained from EPD for disposal at landfill and the necessary requirements. In the latter case criteria for TCLP testing of the acceptability of the immobilised waste for disposal at landfill agreed with EPD (Appendixttachment E) will need to be met prior to treatment and disposal. Whereas landfilling would only usually considered as a last resort, in this case the volume of waste has been estimated at less than 20m³, disposal at the CWTC may not necessarily save significant landfill space.

4.7.32 After discussion with the authorities Therefore the proposed method of disposal was to take a more cautious approach than that described in Appendix E. Rather than treat the already incinerated ash material by incineration, the proposal is for the ash / rubble waste to be collected up and stabilised to meet landfill disposal criteria of the Facilities Management Group of EPD. In this case it is envisaged that the process would involve collection and mixing the ash material with cement. Pilot mixing and TCLP tests should establish the ratio of cement to ash to the satisfaction of EPD. The materials for disposal would then be treated and the extracted material placed into polythene lined steel drums. Transparent plastic sheeting of 0.15mm thickness low-density polythene or PVC should be employed. The drums should be 16 gauge steel or thicker and fitted with double bung fixed ends adequately sealed and well labelled in new or good condition. The drums should be clearly marked (DANGER CHEMICAL WASTE) in English and Chinese. Prior agreement of the disposal criteria from the FMG of EPD and agreement to disposal from the landfill operator must be obtained. collection and mixing the ash / rubble material with cement followed by sealing in polythene lined steel drums. Pilot mixing of the ash with progressively greater proportions of cement (to test for the necessary ratio of cement to ash to prevent leaching of PCDD/PCDF) would precede the treatment.

4.7.33 It is envisaged that the pilot tests would involve the mixing of say 5%, 10% and 15% ratios of cement to ash and three replicate 300mm cube blocks for each ratio. (It is understood that similar approaches to pilot tests on the concentration of cement mixtures for immobilisation have been used at some private sector sites where soil decontamination has been required, however the details have not been available to the consultants). TCLP tests shall than be used to establish the correct ratio of cement to ash to the satisfaction of EPD. The materials for disposal would then be treated and the extracted material mixed with cement and placed into polythene lined steel drums. Transparent plastic sheeting of 0.15mm thickness low-density polythene or PVC should be employed to line the drums. The drums should be 16 gauge steel or thicker and fitted with double bung fixed ends adequately sealed and well labelled in new or good condition. Prior agreement of the disposal criteria from EPD and agreement to disposal from the landfill operator must be obtained. Given that the concentrations of PCDD/PCDF and quantities of ash encountered at KCIP are less than the identified examples the proposals would be adequate for disposal of the contaminated ash.

1.1.1

4.7.34 The SENT Landfill has been identified as the appropriate location for disposal. However, disposal at the CWTC should be considered as a fall back option (as a last resort) if the landfill disposal criteria cannot be met.

Handling and Transportation

1.1.1PCDD and PCDF congeners are chemically related to Polychlorinated Biphenyl (PCB) Wastes and the requirements of the Code of Practice on the Handling , Transportation and Disposal of (PCB) Wastes is generally relevant. Handling, transportation and disposal of the ash waste shall be carried out according to the relevant regulations.

Protection of Site Workers

4.7.35 The release of contaminants from disturbed ash should be minimised prior to gathering up the ash materials and amended water containing a wetting agent should be sprayed on the ash. The wetting agent will assist in water penetration to thoroughly soak the ash and ensure dust levels are reduced without use of excessive water. (Spray shall comprise 50% polyoxyethylene ester and 50% polyoxyethylene ether, or equivalent, diluted to specific concentration in accordance with the manufacturer’s instructions). The use of amended water for dust suppression will minimise the use of excessive water that would result in surface runoff in the removal process. Dust suppression can therefore be carried out in a controlled manner and no insurmountable environmental problem would result.

4.7.36 A HOKLAS accredited laboratory should be appointed to be responsible for sample analysis and also airborne dust monitoring during the abatement works.

4.7.37 Given the nature of the work and the contaminants involved consideration should be given to the use of decontamination facilities (showers) that should be provided for the work force to remove contamination after work.

4.7.38 Preliminary provisions for the protection of workers during the management of the ash removal are presented in Appendix D.

Handling and Transportation

4.7.39 Handling, transportation and disposal of the ash waste shall be carried out according to the relevant regulations.

5 Land Fill Gas Hazard Assessment

5.1 Requirement for Landfill Gas Hazard Assessment

5.1.1 Under Section 6.5, Chapter 9 of the Hong Kong Planning Standards and Guidelines, an evaluation of the risk posed by landfill gas is required for any development proposed within a landfill Consultation Zone (CZ). It is considered that demolition works fall within this category. The CZ is defined as the area of land surrounding the landfill boundary as defined by a line running parallel to and 250 m away from the edge of the waste if this can be identified or, if not, the recognised landfill site boundary.

5.1.2 In June 1997 the Environmental Protection Department (EPD) issued a Guidance Note (Landfill Gas Hazard Assessment Guidance Note, EPD 1997) providing a risk assessment framework for developments proposed close to landfill sites. The Guidance Note (which expands on the general approach set out in EPD's Practice Note for Professional Persons: ProPECC PN 3/96 Landfill Gas Hazard Assessment for Developments Adjacent to Landfills) must be followed when evaluating the risk related to qualifying developments. Generally, a qualitative landfill risk assessment is sufficient to ensure that appropriate levels of safety design features are incorporated within the development. All such assessments must be submitted to EPD for endorsement.

5.2 Scope of Assessment

5.2.1 This assessment has been undertaken with close reference to the Guidance Note and the requirements of the Study Brief (SB) and in line with Annexes 7 and 19 of the TMEIA. The following tasks have been undertaken:

· a review of background information and studies of relevance to the Gin Drinkers Bay Landfill;

· the identification of the sources, nature and likely quantities/concentrations of landfill gas emissions with the potential to affect the KCIP demolition works;

· the identification of likely viable pathways through the ground, underground cavities, utilities or groundwater through which the landfill gas emissions must pass if they are to reach the KCIP site;

· the identification of KCIP demolition activities that would be sensitive to the effects of the landfill gas emissions;

· a qualitative assessment of the degree of risk that the landfill gas emissions may pose to the KCIP demolition activities for the identified source-pathway-target combination; and

· the proposal of appropriate measures to minimise landfill gas hazard during demolition works and associated activities.

5.2.2 The location of KCIP relative to the landfill is indicated in Figure 2.1.

5.3 Potential Landfill Hazards

Potential Hazards Associated with Landfill Gas

5.3.1 Landfill Gas can present a number of potential hazards if not adequately controlled. The following component gasses and properties of landfill gas are of particular concern in relation to developments proposed within a landfill CZ.

Methane

5.3.2 This is a key component of landfill gas, is flammable, and will burn when mixed with air between approximately 5% by volume and 15% by volume (the Lower Explosive Limit (LEL) and Upper Explosive Limit (UEL) respectively). If a mixture of methane and air with a composition between the LEL and UEL is ignited in a confined space, the resulting combustion may give rise to an explosion. Methane is also an asphyxiant.

5.3.3 Methane is odourless and colourless, although in landfill gas it is often associated with numerous highly odoriferous compounds that provide some warning of its presence. However, the absence of odour should not be taken to mean that there is no methane: this can only be confirmed through the use of a properly calibrated methane detector.

Carbon Dioxide

5.3.4 This gas is the other main constituent of landfill gas, and is also an asphyxiant. It causes adverse health effects at relatively low concentrations. The long term Occupational Exposure Limit (OEL) is 0.5% by volume. Similar to methane, in its pure form the gas is odourless and colourless, and its presence may only be confirmed through the use of an appropriately calibrated detector.

Landfill Gas Buoyancy

5.3.5 Methane is lighter than air, whilst carbon dioxide is heavier than air. Landfill gas mixtures are generally likely to have a density close to or equal that of air. However, it is known that site conditions may result in ratios of methane to carbon dioxide causing the landfill gas mixture to be either heavier, or lighter than, air. Consequently, landfill gas may collect at the bottom of trenches or, conversely, may rise up and accumulate beneath structures and foundations.

Potential Hazards Associated with Landfill Leachate

5.3.6 Leachate is the contaminated effluent that drains from a landfill site. Although its composition can vary significantly with the type and age of the contained waste, it is typically highly polluting. Leachate has a high biological oxygen demand (BOD) and may contain high concentrations of compounds such as metal ions, chlorides, sulphates and ammonia compounds. However, due to the above-ground nature of the demolition works, leachate is not considered likely to exert any adverse effects. Leachate in groundwater has been considered in Section 8.

5.4 Landfill Gas Risk Assessment Methodology

5.4.1 The methodology set out in the Landfill Gas Hazard Assessment Guidance Note issued by EPD was adopted in this assessment. For ease of reference, the key points of the Guidance Note are reproduced in the following sections.

Landfill Gas Assessment Criteria

5.4.2 The risk due to landfill gas may be evaluated based upon the following three components:

· Source - the rate and concentration of gas generated by the landfill;

· Pathway - the nature and length of potential pathways through which landfill gas could migrate (such as geological features, utility services and leachate flow); and

· Target - the level of vulnerability of the development (i.e. the demolition and associated works themselves).

5.4.3 These components and their evaluation criteria are discussed in the following paragraphs.

Source

5.4.4 The source (i.e. the landfill) should be evaluated with respect to the following classifications:

Minor

5.4.5 Landfill sites at which gas controls have been installed and proven to be effective by comprehensive monitoring that has demonstrated that no migration of gas beyond the landfill boundary (or any specific control measures). The landfill must have measures to control gas that do not rely solely on an active gas extraction system or any other single control measure which is vulnerable to failure; or

5.4.6 Old landfill sites where the maximum concentration of methane within the waste, as measured at several location across the landfill and on at least four occasions over a period of at least six months, is less than 5% v/v.

Moderate

5.4.7 Landfill sites at which some form of gas control has been installed (e.g. a lined site or one where vents or barriers have been retrospectively installed), but where there are only limited monitoring data to demonstrate prevention of off-site gas; or

5.4.8 Landfill sites where comprehensive monitoring has demonstrated that there is no migration of gas beyond the landfill boundary but where the control of gas relies solely on an active gas extraction system or any other single control system that is vulnerable to failure.

Major

5.4.9 Recently filled landfill sites at which there is little or no control to prevent migration of gas or at which the efficacy of the gas control measures has not been assessed; or

5.4.10 Any landfill site at which monitoring has demonstrated that there is significant migration of gas beyond the site boundary.

Pathway

5.4.11 The broad classification of the Pathway is as follows:

Very Short/Direct

5.4.12 Path length of less than 50 m for unsaturated permeable strata and fissured rock or less than 100 m for anthropogenic conduits.

Moderately Short/Direct

5.4.13 Path length of 50 - 100 m for unsaturated permeable soil or fissured rock or 100 - 250 m for anthropogenic conduits.

Long/Indirect

5.4.14 Path length of 100-250 m for unsaturated permeable soils and fissured rock.

5.4.15 In classifying the pathway, adjustment to the above general guidelines may be required to take account of other factors that can affect the extent of gas migration. Such factors include:

· the particular soil permeability;

· the packing, tightness and direction of the fissures or joints;

· topography;

· depth and thickness of the medium through which the gas may migrate (this maybe affected by groundwater level);

· the nature of the strata over the potential pathway;

· the number of different pathway media involved; and

· the depth to groundwater table and groundwater flow patterns.

Target

5.4.16 Targets may be classified according to the following evaluation criteria:

High Sensitivity

5.4.17 Buildings and structures with ground level or below ground rooms/voids or into which services enter directly from the ground and to which members of the general public have unrestricted access or that contain sources of ignition. This would include developments where there is a possibility of additional structures being erected directly on the ground on an ad hoc basis and without regard to the potential risks.

Medium Sensitivity

5.4.18 Other buildings, structures or service voids where there is access only by authorised, well trained personnel, such as the staff of utility companies, who have been briefed on the potential hazards relating to landfill gas and the specific safety procedures to be followed. Deep excavations also fall into this category unless covered specifically elsewhere.

Low Sensitivity

5.4.19 Buildings/structures that are less prone to gas ingress by virtue of their design (such as those with a raised floor slab), shallow excavations or developments that involve essentially outdoor activities but where evolution of gas could pose potential problems.

5.4.20 These evaluation criteria should only be used as a general frame of reference, and particular aspects of a building or development may render it more or less sensitive than indicated. Account should be taken of any particular circumstances when assigning a target to any category.

Qualitative Assessment of Risk

5.4.21 Once the status of each of the source, pathway and target have been evaluated against the above criteria, a qualitative assessment of the overall risk may be made with reference to the matrix set out in Table 5.1.

Table 5.1 Qualitative Risk Assessment Matrix

Source	Pathway	Target Sensitivity	Risk Category
Major	Very Short / Direct	High	Very High
		Medium	High
		Low	Medium
	Moderately Short / Direct	High	High
		Medium	Medium
		Low	Low
	Long / Indirect	High	High
		Medium	Medium
		Low	Low
Moderate	Very Short / Direct	High	High
		Medium	Medium
		Low	Low
	Moderately Short / Direct	High	High
		Medium	Medium
		Low	Low
	Long / Indirect	High	Medium
		Medium	Low
		Low	Very Low
Minor	Very Short / Direct	High	High
		Medium	Medium
		Low	Low
	Moderately Short / Direct	High	Medium
		Medium	Low
		Low	Very Low
	Long / Indirect	High	Medium
		Medium	Low
		Low	Very Low

5.5 Description and History of Gin Drinkers Bay Landfill

Landfill History

5.5.1 Prior to 1960, Gin Drinkers Bay was an open body of water between Pillar Island and Kowloon with a maximum water depth of about 13m. Before tipping commenced, a rock bund was built connecting the island to the mainland. Initially, waste was received by barge and after being unloaded on the rock bund was pushed eastwards into the sea. Filling also proceeded from the north with a bund of inert waste being placed along the current alignment of Hing Fong Road. This bund was finished in 1963 to prevent wastes from entering the adjacent waterway. Tipping into the water ceased in 1967 although "open tipping" continued until 1973 when controlled landfilling was adopted. Waste deposition ceased in 1979.

5.5.2 Given the age of the site, details about its history are rather vague. However, it is estimated that between 8 and 12 million tonnes of domestic and industrial wastes were deposited. The waste covers an area of approximately 30ha and is a maximum of 55-60 m deep. At its deepest part, the waste extends 10 - 14 m below sea level. The site was not lined prior to filling although a perimeter leachate collection system was installed along the toe of the fill that discharges by gravity into the foul sewer system. The cover material over the waste comprises silty sand and gravel derived from completely decomposed granite (CDG) with additional clayey fill in some locations. The fill cover generally varies in thickness from
1 - 8m.

5.5.3 Following completion of the filling and placement of the cover soils, several thousand trees were planted on the site and preliminary works for development of the site as a community park (Kwai Chung Park) were undertaken by Regional Services Department. These works were suspended in the early 1990s as plans were finalised for the construction of a railway viaduct that would cut through part of the site. The railway viaduct, a part of MTRC's Lantau and Airport Railway project, has now been completed and the portions where works cut through the waste have been capped with a polyethylene membrane and restoration soil. The intention was to control the infiltration of rainwater and the release of landfill gas.

5.5.4 Restoration of the remainder of the site, including the installation of landfill gas and leachate control measures, is now being has been undertaken by a contractor appointed by EPD as part of its programme to restore old landfill sites in Hong Kong.

Geology and Hydrogeology

5.5.5 The deposited waste is generally underlain by marine deposits and alluvial / colluvial sediments, that are in turn underlain by varying thicknesses of moderately or completely decomposed granite bedrock.

5.5.6 The hydraulic gradient of the groundwater in the area of the landfill is complex, but flow direction is assumed to be radial (as reported in the Restoration of Urban Landfills Study - RULS - Working Paper 2) and primarily south-westerly in direction. Water levels within the waste are reportedly as much as 10 - 17 m above surrounding groundwater levels. This may be due to the relatively low permeability of the marine sediments underlying the wastes, causing a flow of leachate outwards towards the perimeter drain, as well as confinement of the groundwater mass below this impermeable layer.

Landfill Gas Generation and Control

5.5.7 The feasibility study for the restoration of the site, ongoing since the early 1990s, has included the monitoring of numerous gas wells and service voids, around the perimeter of the site for the presence of landfill gas. As a component of the restoration study, the current and projected rates of gas generation were estimated and a conceptual design for a gas control system was proposed. It was estimated that the total rate of gas generation for the whole site was approximately 1200 m³ hr^-1 in 1992 and that this would fall to approximately 900m³ hr^-1 in 1997.

5.5.8 A number of passive vents, comprising vertical wells with venting stacks, were installed in the waste along the north-west boundary. The restoration feasibility study proposed the installation of a perimeter trench passive gas collection system around the entire site in addition to a central passive collection system on the southern platform and a central active extraction system on the northern platform.

5.5.9 As part of the work undertaken for the Lantau and Airport Railway (LAR), consultants employed by MTRC predicted that the rate of gas generation for the landfill site would be 490 - 540 m³ hr^-1 in 1997. As part of its LAR works, MTRC has installed a passive gas venting system along each side of the railway cutting. This was designed to vent to atmosphere any gas arising from beneath the railway running platform, as well as the cutting slopes.

5.5.10 A summary of relevant results from landfill gas monitoring conducted between October 1997 and January 1999 at Gin Drinkers Bay are presented in Appendix B. Monitoring wells along the south-western side of the landfill (identified as GDB1, GDB2, GDBGW4 and GDBGW5) are the most relevant to the KCIP site, and indicate concentrations up to 73.3% for methane, 34.4 % for carbon dioxide and down to 0% for oxygen. These very high levels of methane and carbon dioxide and the corresponding depleted levels of oxygen are possibly due to liberation of landfill gasses from organic materials in the fill materials some of which are below the KCIP site near the south-eastern boundary. Such contamination under the site would be removed as part of the soil remediation action plan.

Leachate Generation and Control

5.5.11 The landfill was not lined prior to filling, although a perimeter leachate collection system was installed in the early years of the operation of the site. A paucity of historical leachate flow and composition data led to a proposal to undertake leachate pumping trials in the mid-1990s. These tests were abandoned because it was concluded that the existing leachate collection system was either inoperable or highly inefficient. This is consistent with the age of the collection system. It was also noted that the existing drainage system was located at too high an elevation to intercept the leachate effectively. Any leachate that is not intercepted by the collection system is likely to migrate in a westerly direction towards the Kwai Chung typhoon shelter.

5.5.12 Modelling of leachate flows was conducted as part of the feasibility study for restoration works for Hong Kong Government. Results have indicated that approximately 150,000 m³ of leachate is generated each year. Groundwater modelling results indicated that up to 90 % of this leachate could be intercepted if the perimeter collection system was renovated. The restoration study recommended the installation of a new perimeter drain with a number of pumping stations from which the collected leachate would be pumped to a leachate treatment plant. Similar to the gas management system, the ultimate design of the leachate controls is the responsibility of the contractor appointed by EPD to undertake the design, construction and operation of the landfill restoration works.

Landfill Restoration

5.5.13 Gin Drinkers Bay is one of four North West New Territories (NWNT) landfills in the restoration programme being implemented by the Hong Kong Government. The purpose of the restoration works is to manage the environmental impacts arising from the sites (i.e. landfill gas, leachate, odour etc.) and to enable the sites to be returned to suitable types of after-use. Potential after-uses include public parks, open space, tennis courts, sitting out areas etc. Restoration of the site includes the installation of landfill gas and leachate control measures.

5.5.14 The actual design of the gas and leachate control systems is the responsibility of the tenderer awarded the contract by EPD. The restoration works take the form of a "design, build and operate" (DBO) contract. The contract specifies a series of performance criteria whose objectives include the prevention of significant landfill gas off-site migration. It is understood that part of the contract for the DBO restoration for Gin Drinkers Bay Landfill is not yet completed.

5.6 Description of Target Activities

5.6.1 The preferred demolition methodology has been described in Section 2. The general approach and activities are summarised here to assist the reader.

General Approach

5.6.2 The principle of the demolition procedure for the upper portion of the chimney (10m from ground level or greater) is that the chimneys will be cut into small pieces by hand held tools by operatives on working platforms inside the chimney. Hydraulic breakers would be used for the remaining lower portions of the chimneys. The concrete liner and the metal flues will be removed manually. being cut up into pieces and lowered to the ground by derrick. This method would ensure that full control of the debris and that the pieces of reinforced concrete are not left to free fall.

5.6.3 All such activities will take place above ground level. Demolition tasks will end at ground level, and no works below ground level are anticipated with respect to demolition. In order to avoid hazards caused to the adjacent areas, all the structures and other buildings near to the chimneys would be demolished and removed prior to the demolition of the chimneys. In accordance with the characteristics set out above (Section 5.4) the demolition works (i.e. the Target) should be assigned a sensitivity of low due to the unconfined nature of the activities.

5.6.4 Soil remediation activities will take place at levels below the ground surface but the excavation of materials will be in open excavations with little chance of restricted ventilation. The potential for the build up of methane or carbon dioxide from landfill gas is low to medium risk due to the available ventilation. Therefore the soil remediation works (i.e. the Target) should be assigned a sensitivity of medium as a cautions approach despite the nature of the activities are likely to be unconfined.

5.6.5 Whereas the demolition of the chimney is a specialised operation and above ground the possibility of the build up of methane in such a potentially confined space has been considered. However, large portions of the chimney weather shield at ground level are open as the ducts have been removed and there is a large access door. The potential for the build up of methane or carbon dioxide from landfill gas is in principle a landfill gas hazard issue, however, in practice this would be a low risk due to the available ventilation. Nevertheless, suitable protection measures have been proposed in the Site Investigation Report and the demolition contractor will be required to produce a Safety Plan. This would be in line with the requirements of the Draft Code of Practice for Demolition of Buildings (Buildings Department 1998) which shall be observed at the detailed design stage.

Other Relevant Target Activities

5.6.6 As described in the foregoing section, the demolition works and soil remediation are considered as having low to medium sensitivity to landfill gas hazard. This is primarily due to the above-ground and open nature of the works, which would be well ventilated. Land contamination investigations, required as part of the current EIA study have been undertaken below ground level without incident. Detailed plans for intrusive ground investigations were formulated with caution and were assigned a sensitivity to landfill gas hazard of medium. Any future underground activities requiring excavation were assigned a sensitivity to landfill gas hazard of medium and should be approached with caution.

5.7 Ground Between Landfill and KCIP

Landuse and Topography

5.7.1 The Kwai Chung Incineration Plant is located at Kwai Yue Road, Kwai Chung, facing the Rambler Channel and Tsing Yi South Bridge, with a site area of about 14,000m2. The site lies immediately adjacent to the former Gin Drinkers Bay Landfill, and therefore may be impacted by contaminants and landfill gas generated from the landfill site.

5.7.2 The KCIP site is currently zoned as “G/IC”, with no identified long-term use of the area after demolition. However, the future land use is unlikely to be residential given the close proximity of the site to Gin Drinkers Bay Landfill and the Rambler Channel Bridge.

5.7.3 A Public Filling Barging Point (PFBP), located on reclaimed land (Area 30D) to the north of the KCIP, is planned to be operational in early 2005. Construction of the PFBP is scheduled to commence in early 20034 and is planned to be operational in early 2005for completion by the end of 2004. The PFBP has been subject to EIA under a separate study.

5.7.4 The site is opposite the Rambler Channel Typhoon Shelter and Public Cargo Working Area. These facilities accommodate a range of cargo related activities including permanently moored barges.

Natural Geology and Hydrogeology

Natural Geology

5.7.5 Portions of the historic shoreline, including the former Gin Drinkers Bay, were reclaimed after 1960 using sanitary fill materials and Holocene marine sands and muds. Superficial deposits around the perimeter of the former Bay include older debris flow deposits in hilly areas and alluvium in valleys. The alluvial deposits overlie bedrock that has been weathered to varying degrees. These materials are of most relevance to the study site.

5.7.6 A review of the Hong Kong Geological Survey's (HKGS) Solid and Superficial Geology Map Sheets 7 (Sha Tin) and 11 (Hong Kong and Kowloon), and Survey Memoirs No. 2 (Geology of Hong Kong Island and Kowloon) and No. 3 (Geology of the Western New Territories), indicated that the geology in the vicinity of Kwai Chung Park is dominated by Jurassic-Cretaceous granitic plutonic rocks, notably fine and medium grained granite, and older granodiorite. A series of north-east to south-west trending high angle dykes of feldsparphyric rhyolite, fine grained granite and basalt form minor intrusions in the granodiorite persist to the north of the landfill site. Where completely decomposed, the granitic bedrock forms medium to coarse sand. However, this information is of lesser importance as the study site is located entirely on reclamation fill as described above.

Hydrogeology

5.7.7 The hydraulic gradient of the groundwater in the area of the landfill is complex and largely unconfirmed due to limited data. The gradient of the groundwater in the area of the landfill is assumed to be shallow, and flow direction is assumed to be radially from the landfill and primarily south-westerly in direction, consistent with the topographic valley draining in the Kwai Chung area.

5.7.8 Water levels within the fill are reportedly 10 -17 m above surrounding groundwater levels. This effect may be due to the relatively low permeability of the underlying marine deposits and alluvial materials causing a flow of leachate outwards.

5.7.9 A 'superficial' aquifer is identifiable within the granular sediments (alluvium, fill and completely decomposed bedrock), in addition to a separate 'bedrock' aquifer. Groundwater monitoring data is limited. However, it is suspected that groundwater in the superficial deposits is confined by the varying permeabilities of the materials present. Perched water above the less permeable marine sediments has been recorded in boreholes within the CZ. The groundwater flow in the granitic bedrock is expected to take place primarily through fractures and joints.

5.7.10 Groundwater data reviewed between January 1992 (RULS WP6) and the present is inconsistent, although groundwater 'spot' sampling was conducted by the KCRC West Rail engineering preliminary design consultants by means of the gas monitoring wells installed in December 1997. Subsequent assays indicated concentrations of inorganic compounds such as metal ions, chlorides and sulphates did not provide any evidence of leachate and most likely represent normal background levels. It is probable that high sodium and chloride levels are due to the site having been reclaimed from the sea, and because waste was originally deposited directly into seawater.

Intervening Ground

5.7.11 The KCIP is located in very close proximity to Gin Drinkers Bay Landfill (Figure 2.1). The ground separating the two sites is covered is sealed and comprises Kwai Yue Road and pavements on either side. It is understood that the underlying material is fill used in the original land reclamation process. As such, it is assumed that the unsaturated fill material is porous and conducive to gas migration. It is considered that the potential gas migration pathway should be classified as very short/direct.

5.8 Landfill Gas Risk Assessment

Source

5.8.1 The Gin Drinkers Bay Landfill contains a substantial volume of waste and is a major source of gas. The estimated that the rate of gas production in 1997 ranged from 490 - 900m³ hour^-1. When initially constructed the landfill site contained few measures to control either landfill gas or leachate. Although some measures were retrospectively installed, due to the age and nature of these, it is considered that currently only a very low level of protection is provided recent. Recent monitoring data (Appendix B) indicate that landfill gas is present to the south-west of the landfill towards and into the Kwai Chung Incinerator KCIP Plant site.

5.8.2 Gin Drinkers Bay Landfill is currently subject to restoration works to control the level and range of its environmental impacts. It is understood that these works include specific measures to control the off-site migration of both landfill gas and leachate. The appointed Contractor is required to demonstrate that this design meets the performance standards by means of a practical and effective design, and also through a programme of monitoring during both construction and aftercare phases. Following the completion of the restoration works, the landfill would represent a lesser risk with respect to off-site landfill gas (and leachate) migration.

5.8.3 However, in the interest of presenting a conservative and cautious approach to the current assessment, it has been assumed that, in its unmitigated state the Gin Drinkers Bay Landfill is considered as a major source of landfill gas for the purposes of this assessment.

Pathway

5.8.4 The potential pathways for migration of gas from Gin Drinkers Bay Landfill to the KCIP site comprise two categories:

· natural; and

· anthropogenic.

5.8.5 In terms of geological pathways, the ground between the landfill and the Kwai Chung Incinerator Plant site comprises reclamation fill; a good medium for the migration of landfill gas. The pathway for geological transmission pathways is therefore classified in accordance with the guidance note as ‘very short/direct’.

5.8.6 There are several potential anthropogenic migration pathways in the general study area. Principally, these take the form of utility conduits. These are likely to include: water mains, electricity cables, telephone cables and fire hydrants. Such features have the potential to provide an alternative migration pathway to the study site. However, despite the potential presence of these utility conduits the overall sensitivity rating of the migration pathway would not change and would remain as very short/direct in accordance with the Guidance Note.

Targets

5.8.6.1.1.1 Demolition Works

5.8.7 All demolition works will be undertaken above ground level and will end at ground level. As such, these works will be undertaken in the open air and will be subject to maximum potential for natural ventilation. Therefore, the potential for any landfill gas that may have migrated to the KCIP site to accumulate above ground is considered minimal. For these reasons the target sensitivity for the demolition works themselves has been assigned as low.

5.8.7.1.1.1 Soil Remediation

5.8.8 Intrusive ground investigations were required as a component of the current study to determine the extent of ground contamination but were conducted without incident. Contamination is present and whereas further ground investigations are not ruled out it is envisaged that excavation and treatment of isolated sections of the underlying fill materials will take place after the demolition in line with the soil remediation action plan. All staff involved in the ground remediation process will receive a briefing on the hazards of landfill gas. Therefore, in accordance with the Guidance Note, a sensitivity rating of medium has been assigned. This rating covers voids “where there is access only by authorised, well trained personnel who have been briefed on the potential hazards relating to landfill gas and the specific safety procedures to be followed.”

Assessment of Risk

5.8.9 A qualitative assessment of landfill gas risk posed by the Gin Drinkers Bay Landfill to the demolition of Kwai Chung Incinerator and associated activities, as described in this report, is set out in Table 5.2 below.

Table 5.2 Qualitative Risk Assessment

Source	Pathway	Target	Qualitative Risk
Gin Drinkers Bay Landfill (major)	Natural (very short/direct)	General Demolition Activities (Low)	Medium
	Anthropogenic (very short/direct)		Medium
	Natural (very short/direct)	Soil Remediation (Medium)	High
	Anthropogenic (very short/direct)		High

5.8.10 The Qualitative Landfill Gas Risk Assessment has indicated the risk of gas hazard during demolition works as medium for demolition works and high for intrusive site investigations.

5.9 Proposed Protection and Precautionary Measures

5.9.1 The findings of the qualitative assessment have indicated that the risks posed to works for the demolition of KCIP by Gin Drinkers Bay Landfill are medium. The assessment has also shown that potentially medium high risks are posed by ground soil remediation activities needed in response to the land contamination assessment. Whereas the potential risk is high there is a need to ensure that adequate precautionary measures are taken during the soil remediation. However the risk will be reduced due to the open nature of the work and the landfill restoration measures will be in operation by the time the site remediation takes place.

5.9.2 The recommendations for the protection and precautionary measures that should be implemented during ground investigation works take a cautious approach and are indicated below.

Recommended Precautionary Measures

5.9.3 A working method statement (safety plan) is recommended for inclusion into the contract for demolition works. This document should be promulgated to interested parties upon completion. The document should set out the measures and implementation strategies proposed to minimise, inter alia: the risk of fires, uncontrolled explosions and asphyxiation of workers during the construction phase. The safety plan should stipulate the gas measurements required prior to the use of any powered mechanical equipment below ground level. All work should be undertaken strictly in accordance with the safety plan.

5.9.4 All relevant workers should undergo training on the risks and indications of landfill gas and should be thoroughly versed in first aid and emergency and evacuation techniques.

5.9.5 A no smoking policy should be strictly implemented on site and applied at all times.

5.9.6 The possibility of methane rich air being taken into diesel-engine plant should not be overlooked, although this is not likely to occur.

5.9.7 No work should be carried out below ground level in the absence of mechanical ventilation.

5.9.8 All electrical equipment (including extension leads) to be used below ground level should be fitted with spark arrestors or be intrinsically safe.

5.9.9 As a minimum, emergency breathing apparatus should be available for work below ground level and fire extinguishers should be provided (details to be included in the safety plan).

5.9.10 Monitoring of methane, carbon dioxide and oxygen should be undertaken during the works below ground level using suitable equipment. The actions set out in Table 5.3 below should be carried out in the event of gas trigger levels being breached.

5.9.11 Further suggestions for good site practice are presented in Appendix D.

Table 5.3 Landfill Gas Detection Action Plan For Works Below Ground Level

Parameter	Measurement	Required Action
O2	< 19 %	Increase ventilation to restore O2 to >19%
	< 18 %	Stop work
		Evacuate Personnel
		Increase ventilation to restore O2 to >19%
CH4	> 10 % LEL	Prohibit hot works
		Increase ventilation to restore CH4 to < 10 % LEL
	> 20 % LEL	Stop work
		Evacuate Personnel
		Increase ventilation to restore CH4 to < 10 % LEL
CO2	> 0.5 %	Increase ventilation to restore CO2 to < 0.5 %
	> 1.5 %	Stop work
		Evacuate Personnel
		Increase ventilation to restore CO2 to < 0.5 %

5.9.12 Monitoring equipment should have, as a minimum, the indication ranges set out below.

Methane: 0 - 100 % LEL and 0 - 100 % v/v

Carbon Dioxide: 0 - 20 % v/v

Oxygen: 0 - 21 % v/v

· As a minimum, monitoring frequency should be undertaken on an hourly basis and should always be undertaken by suitably qualified personnel.

· As a minimum, all measurements should be taken such that they include the highest and lowest points within the works below ground level.

Site Redevelopment Phase

5.9.13 Redevelopment of the site following completion of demolition works is beyond the scope of the current study. However, once confirmed, it is recommended that designs and plans for subsequent land use are subject to further detailed landfill gas hazard assessment as appropriate.

5.10 Conclusion

5.10.1 The landfill gas hazard assessment has been undertaken with respect to the current proposals for the demolition of KCIP. The assessment has been undertaken in accordance with the Landfill Gas Hazard Assessment Guidance Note issued by EPD.

5.10.2 All demolition works will be undertaken above ground level and in the open air and are therefore not considered unduly susceptible to hazards caused by the accumulation of landfill gas.

5.10.3 Intrusive ground remediation activities including excavations are required. Since such activities must necessarily take place below ground level it has been concluded that, in view of the characteristics and proximity of the landfill, the risk of landfill gas hazard is high. However, recommendations have been made to ensure that all sub-surface works are conducted under safe and controlled conditions through the implementation of a gas monitoring programme.

5.10.4 It is therefore concluded that all demolition and associated works can be completed and the risk of landfill gas hazard can be controlled to acceptable levels.

6 Noise

6.1 Introduction

6.1.1 This section provides an assessment of the noise impacts associated with the demolition of the KCIP that has been conducted in line with Annexes 5 and 13 of the TMEIA. Noise Sensitive Receivers (NSRs) within 700m of the site have been identified (Figure 2.1) and worst case impacts on these receivers modelled.

6.1.2 Potential Nnoise impacts on the NSRs are a potential concern during the demolition of the Kwai Chung Incineration Plant. Mitigation measures are shall be recommended, where necessary, to reduce the noise impacts at the NSRs.

6.2 Government Legislation and Standards

6.2.1 Construction noise is controlled under the Noise Control Ordinance (NCO) and its subsidiary regulations. The NCO provides a statutory control on the noise from general construction work between 7p.m. and 7a.m., Sundays and on general holidays by means of construction noise permits. For general construction work involving the use of powered mechanical equipment (PME) other than percussive piling, the NCO standards are contained in the Technical Memorandum on Noise from Construction Work other than Percussive Piling and the Technical Memorandum on Noise from Construction Work in Designated Areas. The project site falls within the Kwai Tsing Designated Area as shown in Plan No. EPD/NP/NT-03.

6.2.2 Outside restricted hours (i.e. between 07:00 and 19:00 on weekdays other than general holidays), general construction works must meet the noise standards for daytime construction activities laid down in Table 1B of Annex 5 of the Technical Memorandum on Environmental Impact Assessment Process (TMEIA) as far as practicable. Practicable mitigation measures shall be implemented where necessary. Table 6.1 summarises the non-statutory daytime noise criteria. Since the demolition of the Project is expected to be carried out in daytime, the noise standards stated in Table 6.1 have been used for the assessment.

Table 6.1 Noise Standards for Daytime Construction Work

Uses	0700 to 1900 hours on any day not being a Sunday or general holiday Leq (30mins) dB(A)
· All domestic premises including temporary housing accommodation	75
· Hotels and hostels	75
· Educational institutions including kindergartens, nurseries and all others where voice communication is required	70 65 (During examinations)

Notes:

· The above standards apply to uses which rely on opened windows for ventilation.

· The above standards shall be viewed as the maximum permissible noise levels assessed at 1 m from the external façade.

6.2.3 Under the subsidiary regulations of the NCO, hand held percussive breakers and air compressors must comply with a stringent noise standard and fitted with a "noise emission label" before they could be used for work. The maximum permissible sound power levels of a hand held percussive breaker (mass of above 35 kg) and an air compressor (airflow of above 30 m³/min) are 114 dB(A) and 104 dB(A) respectively.

6.2.4 Despite any description or assessment made in the subsequent paragraphs, the Noise Control Authority will be guided by the relevant Technical Memorandum (Memoranda) in assessing an application, once filed, for a Construction Noise Permit (CNP). The authority He will consider all the factors affecting his decision taking contemporary situations/ conditions into account. Nothing in this Report shall bind the Authority in making ahis decision. There is no guarantee that a CNP are being carried out. will be granouted. Failing which the conditions of a CNP will lead to cancellation of the CNP and prosecution action under the Noise Control Ordinance.

6.3 Baseline Conditions

6.3.1 A number of industrial uses, including Kwai Chung Preliminary Treatment Works and public cargo working areas are located around the Site. The approach viaduct of the Rambler Channel Bridge is within 40m of the chimney and the study area of the area is predominantly influenced by road traffic. Construction, commercial and waterfront noise contribute to the background noise at the Site.

6.4 Noise Sensitive Receivers

6.4.1 Noise Sensitive Receiver (NSRs) include domestic premises, hotel, hostel, temporary housing accommodation, hospital, medical clinic, educational institution, place of public worship, library, court of law or performing arts centre. No planned or committed NSRs have been identified to date within 700m study area but there are some existing NSRs. The relevant OZP and NSRs are presented in Ssection 2..

6.4.2 There are few SRs such as residential premises, which are so close to the works at KCIP as to be severely affected by conventional top down demolition method. However NSRs within 700m will be included in the EIA. This includes NSRs in the vicinity of Cheung Ching Estate. Greenfield Garden and Grand Horizon (more than 600m away across the Rambler Channel, Figure 2.1).

6.4.3 Representative NSRs have been identified according to the criteria set out in the TMEIA and the study brief through review of land use plans of the Study Area. Table 12.2 lists the representative NSRs and their horizontal distances from the site boundary. Locations of NSRs are shown in Figure 2.1.

Table 6.2 Representative Noise Sensitive Receivers

NSR	Building	Horizontal Distance from Site Boundary (m)	Use
KC-N1	Cheung Ching Estate (Ching Tao House)	720	13-storey high public housing block
KC-N2	Cheung Ching Estate (Ching Pak House)	640	33-storey high public housing block
KC-N3	Greenfield Garden	688	30-storey high residential block
KC-N4	New Residential Development (seaward side Greenfield GardenGrand Horizon	608	High-rise residential block under construction

6.5 Potential Sources of Impact

6.5.1 The likely noise impacts arising from the demolition of the Kwai Chung Incineration Plant are related to operation of demolition plant and vehicles.

6.5.2 Major noise generating activities associated with the demolition works are mechanical demolition of building structures, transfer of waste materials on to lorries and the movement of vehicles.

6.5.3 The demolition of Kwai Chung Incineration Plant is expected to take about 12 months however there is at present no fixed programme for the works. The debris storage will be temporary and waste materials would be taken off-site as soon as possible. The public Fillpublic filling Barging Point (Area 30D adjacent to the north) may be operable by the time of the works and this could facilitate disposal of some types of the demolition wasteC&D material. The mechanical demolition of the buildings will be carried out at the beginning of the demolition period while the demolition of chimney would be undertaken at a later stage. These two activities will not, therefore, be carried out concurrently.

6.6 Assessment Methodology

6.6.1 The assessment of the potential noise impact from the demolition works was based on standard acoustic principles. The assessment procedure was made reference to the technical memorandum on Noise from Construction Work other than Percussive Piling (the Technical Memorandum) issued under the NCO. Where no sound power levels can be found in the Technical Memorandum, reference was made to BS5228 Part I or noise emission levels measured in previous projects in Hong Kong.

6.6.2 The TMCW specifies sound power levels of common construction equipment, assessment procedure and correction for influencing factors. The corrected noise levels were calculated by taking into account the following influencing factors:

· Sound Power Level - The sound power level of each item of Powered Mechanical Equipment (PME) is listed in the Technical Memorandum.

· Distance Attenuation - All items of PME have been considered to be grouped at the notional source position that is a point mid-way between the approximate geographical centre of the construction site and its boundary nearest to the NSR. The distance between the NSR and the notional source position attenuates the noise level. The corresponding correction factors are set out in the Technical Memorandum.

· Barrier Effect - According to the Technical Memorandum, a negative correction of 10 dB(A) can be applied to the predicted noise level when the NSR is considered to be totally screened. A negative correction of 5 dB(A) can be applied if the NSR is considered to be partially screened.

· Façade Correction - A positive correction of 3 dB(A) has been applied to consider the effect of reflection from facades.

6.6.3 The noise emissions at demolition sites are associated with use of mechanical plant for demolition operations. Demolition works and truck movements are the two major noise generation activities for the demolition. Whereas the demolition of the main building and the chimney will take place separately, for a worst-case scenario in the model, it was assumed that all equipment would be fully utilised simultaneously, although this situation would not be likely to occur in practice. An inventory of noise sources including demolition equipment and other associated construction equipment was developed based on the consultants experience of other typical demolition contracts and consultation with experienced demolition contractors and civil engineers in the field. The proponents (CED) have endorsed the proposed suite of powered mechanical equipment as representative. In the absence of a detailed programme and method statement from the eventual demolition contractor, the proposed demolition methods, programme and equipment inventory are reasonable and valid assumptions based on the available information and practical experience of similar Hong Kong demolition activities. Table 6.3 lists the type and number of equipment / plant to be used. Table 6.4 lists the type and number of equipment / plant to be used during the soil decontamination phase.

6.6.4 The demolition works will be carried out at different elevations and, therefore, the height of emissions for the noisy activities will vary. However the horizontal distance to the receivers is much greater than the variation in height of source, therefore any differences in distance due to height are insignificant. Thus it is relevant to use only horizontal distances between the notional source and receivers, to predict the worst case noise levels at the NSRs.

Table 6.3 Anticipated Demolition/Construction Plant

Construction Plant	CNP No.	SWL, dB(A)	Quantity
			Months 1-2	Months 3-6	Months 7-8	Months 9-12
Generator, silenced	102	100	2	2	2	2
Air Compressor	003	104	0	2	2	2
Crawler Mounted Hydraulic Breaker	028	122	0	4	6	4
Excavator/Backhoe	081	112	1	3	6	3
Crawler/Mobile Crane	048	112	1	2	2	2
Lorry/Dump Truck	067	117	02	5	20	5
Pneumatic Breaker	026	114	1	3	10	3
Cutter/Chain Saw	2034	115	01	3	10	3
Water Pump	281	88	4	4	4	4
Crane Shaft and Derrick	049	95	0	1	1	1
Total SWL per month, dB(A)			123	131	134	131

Table 6.4 Anticipated Construction Plant for Soil Remediation

Construction Plant	CNP No.	SWL, dB(A)	Quantity
			Months 1-2	Months 3-6	Months 7-8	Note
Generator, silenced	102	100	2	2	2
Air Compressor	003	104	2	2	2
Excavator/Backhoe	081	112	2	2	2
Lorry/Dump Truck	067	117	2	3	3
Pneumatic Breaker	026	114	2	2	2
Water Pump	281	88	4	4	4
Ballast Tamper	029	105	1	1	1
Concrete Mixer	045/46	96	2	2	2
Vibratory Compactor	050	105	2	2	2
Total SWL per month, dB(A)			123	124	124

6.7 Evaluation of Impacts

6.7.1 The likely noise impacts on the NSRs were modelled and the results are presented in Table 6.5.

Table 6.5 Predicted Unmitigated Noise Levels – Demolition Plant

NSR	Period	SWL, dB(A)	DA, dB(A)	FC, dB(A)	PNL, dB(A)
KC-N1	Months 1-2	123	-65	3	61
	Months 3-6	131			69
	Months 7-8	134			72
	Months 9-10	131			69
KC-N2	Months 1-2	123	-64	3	62
	Months 3-6	131			70
	Months 7-8	134			73
	Months 9-10	131			70
KC-N3	Months 1-2	123	-65	3	61
	Months 3-6	131			69
	Months 7-8	134			72
	Months 9-10	131			69
KC-N4	Months 1-2	123	-64	3	62
	Months 3-6	131			70
	Months 7-8	134			73
	Months 9-10	131			70

Note: SWL denotes sound power level. DA denotes distance attenuation.

FC denotes façade correction PNL denotes predicted noise level

6.7.2 The modelling results showed that whereas the extent of construction (demolition) activities will be significant no noise exceedance would be expected at all NSRs. During the peak of activity (months 7 to 8). the predicted noise levels will not exceed the Noise Standards for Daytime Construction Activities of 75 dB(A) for domestic premises under the TM of the EIAO. No nightime work is anticipated.

6.7.3 The modelling results for activities during the soil remediation phase showed that the noise emanating from the site would be less than during the construction (demolition) activities. Therefore no noise exceedance would be expected at any of the NSRs and the predicted noise levels would not exceed the Noise Standards for Daytime Construction Activities of 75dB(A). No nightime work is anticipated.

6.8 Conclusions

6.8.1 Without mitigation, the predicted noise levels at the NSRs will be within the established criteria during demolition and soil remediation phases of the project. This is due to the moderate amounts of plant likely to be operating and great separation distance between the noise sources and the NSRs. Therefore, noise is not expected to exceed established standards and criteria during the demolition works or soil remediation processes. Whereas no EM&A is recommended for noise, some informal monitoring is recommended suggested and the EM&A team should keep a watching brief on noise as a proactive measure in order to ensure that good site practices are adopted as far as practicable. This will help avoid unnecessary noise generated by the construction/demolition works (such as machine idling).

7 Air Quality

7.1 Introduction

7.1.1 The preferred demolition methods have been agreed. Based on professional judgement air quality assessment is not required because of the nature, scale and location of this Project is far from and air sensitive receivers. In addition the elected demolition method will not include blasting techniques and that the requirements of the Air Pollution Control (Construction Dust) Regulation, under the APCO will apply, ensuring that air quality is in compliance with established standards and criteria. The preferred demolition method, is not balasting, but is top-down deconstruction. However, Iin order to provide some reference material with regard to air quality, at at this stage, all Air Sensitive Receivers (ASRs) within 700m proximity to the site have been identified.

Table 7.1 Representative Air Sensitive Receivers

ASR	Building	Horizontal Distance from Site Boundary (m)	Use
KC-A1	Cheung Ching Estate (Ching Tao House)	720	13-storey high public housing block
KC-A2	Cheung Ching Estate (Ching Pak House)	640	33-storey high public housing block
KC-A3	Greenfield Garden	688	30-storey high residential block
KC-A4	Grand Horizon	608	High-rise residential block under construction

7.1.2 Potential dust impacts on the ASRs are the major concern during the demolition of the incinerator plant buildings and chimney. Mitigation measures are required under the Air Quality (Construction Dust) Regulations, to reduce the air quality impacts at the ASRs.

Table 7.2 Hong Kong Air Quality Objectives (mg/m³) ^(a)

Pollutant	Averaging Time
	1 Hour ^(b)	8 Hour ^(c)	24 Hour ^(c)	1 Year ^(d)
Total Suspended Particulates (TSP)	(500) ^(f)	-	260	80
Respirable Suspended Particulates ^(e) (RSP)	-	-	180	55
Nitrogen Dioxide (NO2)	300	-	150	80
Sulphur Dioxide (SO2)	800	-	350	80
Carbon Monoxide (CO)	30,000	10,000	-	-
Note: a) Measured at 298K (25^oC) and 101.325 kPa (one atmosphere). b) Not to be exceeded more than three times per year. c) Not to be exceeded more than once per year. d) Arithmetic means. e) Respirable suspended particulates are defined as particles suspended in the air with a nominal aerodynamic diameter of 10 mm and smaller. f) Technical Memorandum of Environmental Impact Assessment Process (TMEIA) stipulates a maximum TSP level of 500 mg m^-3 (1-hour averaging time).

7.2 Government Legislation and Standards

7.2.1 The principal legislation for the management of air quality is the Air Pollution Control Ordinance (APCO) (Cap 311). The whole of the Hong Kong Territory is covered by the Hong Kong Air Quality Objectives (AQOs) which stipulate the statutory limits of some typical air pollutants and the maximum allowable numbers of exceedances over specific periods. The AQOs are shown in Table 7.1.

7.2.2 The Air Pollution Control (Construction Dust) Regulation came into operation in June 1997 This legislation requires notification before carrying out of certain types of construction works and to adopt dust reduction measures while carrying out construction activities.

7.3 Dust Suppression Measures

7.3.1 The fugitive dust emissions relevant to this demolition site are associated with general deconstruction and mechanical demolition of structures, land clearing, soil decontamination procedures and the movement of trucks on unpaved haul roads. These sources will essentially involve general disturbance of the existing structures above ground and waste-moving activities. In traditional demolition some portion of the dust associated with the demolition could also result from falling structures although this is ruled out by the preferred demolition method.

7.3.2 In order that nuisance to residential sensitive receivers is minimised, it is important to minimise dust emissions from construction activities. The Air Pollution Control (Construction Dust) Regulation control dust emission from construction works. Appropriate dust control measures should be implemented during construction stage and carried through to the soil remediation phase in accordance with the requirements in this legislation. Dust control techniques should be considered to control dust to a level not exceeding the Air Quality Objectives (AQOs) as well as the 1-hour TSP guideline level. These measures include:

· Adoption of good site practices;

· Avoid practices likely to raise dust level;

· Frequent cleaning and damping down of stockpiles and dusty areas of the site;

· Stock piles shall be covered by impervious sheeting; or

· Stockpiles shall be placed in areas sheltered on the top and three sides;

· Stock piles shall be sprayed with water mist or a dust suppression chemical to maintain the entire surface damp;

· Reducing drop height during material handling or wall felling;

· Imposing a vehicle speed restriction of 15 km/hr within the site;

· Provision of wheel washes facilities for site vehicles leaving the site;

· Regular plant maintenance to minimise exhaust emission; and

· Sweep up dust and debris at the end of each shift.

7.3.3 Statutory control of dust emissions from construction (demolition) works requires appropriate dust control measures to be implemented during the construction stage in accordance with the requirements in the Air Pollution Control (Construction Dust) Regulation. Using the above-mentioned measures and requirements in the Air Pollution Control (Construction Dust) Regulation, the dust nuisance to the surrounding air sensitive receivers can be minimised. With such mitigation, the predicted dust levels at the ASRs will be within the established criteria, therefore excessive dust during demolition works is not expected. Using the above-mentioned measures and requirements in the Air Pollution Control (Construction Dust) Regulation, the dust nuisance to the surrounding sensitive receivers can be minimised. In addition, as a proactive measure, the Environmental Monitoring and Audit (EM&A) for dust generated during the demolition is also recommended at the site boundary at the west to ensure that the dust criteria will not be exceeded at the Kwai Chung PTW. EM&A for dust is recommended at the site boundary to ensure that the dust criteria will not be exceeded and as a proactive measure and to ensure that local nuisances do not arise.

7.4 Vehicle Emissions

7.4.1 Demolition traffic, such as waste removal lorries, will approach and egress from the site during the demolition. Whereas the exact volume of waste to be disposed of has not yet been determined, estimates indicate that up to about forty lorries per day would be required during the peak activities. Thus fewer than ten heavy vehicles per hour would be required to remove waste from the Site. Background flows of traffic moving in the area (based on the 1999 Annual Traffic Census, e.g. Kwai Tsing Road) are greater than thirty thousand vehicles per day. Potential additional vehicular emissions due to an additional forty or so vehicles moving to and from the site would not create any significant increase to vehicular emissions in the area. The site is open and the emissions from petrol or diesel powered mechanical equipment used on the site would be rapidly dispersed in both the demolition and soil remediation phases such that no significant accumulation of vehicular emissions would occur.

7.5 Odour

7.5.1 During the intrusive site investigations samples of the underlying ground were excavated from borehole down to significant depth. There were no strong odours associated with any of these samples. The site is open and the distances to sensitive receivers is significant such that even if some previously unidentifiable materials with minor odours were excavated during soil remediation, odours from such sources would be rapidly dispersed such that no significant odour problem would be likely to occur.

7.6 Conclusions

7.6.1 With the adoption of appropriate dust suppression measures, construction dust is unlikely to cause significant adverse impacts on surrounding sensitive receivers. Effective and adequate dust suppression measures could be ensured during the whole demolition period by the observation of the Air Pollution Control (Construction Dust) Regulations. Vehicles moving to and from the site and around the site would not create any significant increase to vehicular emissions in the area. The underlying soils are not odorous and no significant odour problem would be likely to occur.

8 Water Quality (KCIP)

8.1 Introduction

8.1.1 This section provides an assessment of the potential water quality impacts associated with the demolition of KCIP in line with the SB and Annexes 6 and 14 of the TMEIA.

8.1.2 Key issues addressed in this section are the generation of demolition run-off surplus water from soil remediation and wastewater that may cause adverse water quality impacts on water sensitive receivers if not properly controlled. Where appropriate, mitigation measures have been proposed to control potential water quality impacts.

8.2 Government Legislation and Standards

8.2.1 Under the Technical Memorandum on Environmental Impact Assessment Process, Revised Draft, April 1997 and the Water Pollution Control Ordinance (WPCO), Hong Kong waters are subdivided into 10 Water Control Zones (WCZs). Each WCZ has a designed set of statutory Water Quality Objectives (WQOs). For this study, the marine waters of the Victoria Harbour WCZ on the eastern side of the Rambler Channel could be directly affected by demolition discharges from the KCIP. The waters of the Western Buffer WCZ on the eastern site of the Rambler Channel may be affected indirectly.

8.2.2 The WQOs for the Victoria Harbour (Table 8.1) will be applicable as evaluation criteria for assessing the compliance of the Project.

Table 8.1 Water Quality Objectives (WQOs) for Victoria Harbour

Water Quality Objective	Part or Parts of Zone
A. AESTHETIC APPEARANCE
There should be no objectionable odours of discolouration of the water.	Whole zone
Tarry residues, floating wood, articles made of glass, plastic, rubber or of any other substances should be absent.	Whole zone
Mineral oil should not be visible on the surface. Surfactants should not give rise to a lasting foam.	Whole zone
There should be no recognisable sewage-derived debris.	Whole zone
Floating, submerged and semi-submerged objects of a size likely to interfere with the free movement of vessels, or cause damage to vessels, should be absent.	Whole zone
The water should not contain substances which settle to form objectionable deposits.	Whole zone
B. BACTERIA
The level of Escherichia coli should not exceed 1 000 per 100 mL, calculated as the geometric mean of the most recent 5 consecutive samples taken at intervals of between 7 and 21 days.	Inland waters
C. COLOUR
Human activity should not cause the colour of water to exceed 50 Hazen units.	Inland waters
D. DISSOLVED OXYGEN
a) The level of dissolved oxygen should not fall below 4 mg per litre for 90% of the sampling occasions during the whole year; values should be calculated as the annual water column average (see Note). In addition, the concentration of dissolved oxygen should not be less than 2 mg per litre within 2 m of the seabed for 90% of the sampling occasions during the whole year. b) The level of dissolved oxygen should not be less than 4 mg per litre.	Marine waters Inland waters
E. pH
a) The pH of the water should be within the range of 6.5-8.5 units. In addition, human activity should not cause the natural pH range to be extended by more than 0.2 unit.	Marine waters
b) Human activity should not cause the pH of the water to exceed the range of 6.0-9.0 units.	Inland waters
F. TEMPERATURE
Human activity should not cause the daily temperature range to change by more than 2.0 ^oC.	Whole zone
G. SALINITY
Human activity should not cause the salinity level to change by more than 10%.	Whole zone
H. SUSPENDED SOLIDS
a) Human activity should neither cause the suspended solids concentration to be raised more than 30% nor give rise to accumulation of suspended solids which may adversely affect aquatic communities.	Marine waters
Human activity should not cause the annual median of suspended solids to exceed 25 mg per litre.	Inland waters
I. AMMONIA
The un-ionized ammoniacal nitrogen level should not be more than 0.021 mg per litre, calculated as the annual average (arithmetic mean).	Whole zone
J. NUTRIENTS
a) Nutrients should not be present in quantities sufficient to cause excessive or nuisance growth of algae or other aquatic plants.	Marine waters
b) Without limiting the generally of objective (a) above, the level of inorganic nitrogen should not exceed 0.4 mg per litre, expressed as annual water column average (see Note).	Marine waters
K. 5-DAY BIOCHEMICAL OXYGEN DEMAND
The 5-day biochemical oxygen demand should exceed 5mg per litre.	Inland waters
L. CHEMICAL OXYGEN DEMAND
The chemical oxygen demand should not exceed 30 mg per litre.	Inland waters
M. TOXIC SUBSTANCES
a) Toxic substances in the water should not attain such levels as to produce significant toxic, carcinogenic, mutagenic or teratogenic effects in humans, fish or any other aquatic organisms, with due regard to biologically cumulative effects in food chains and to interactions of toxic substances with each other.	Whole zone
b) Human activity should not cause a risk to any beneficial use of the aquatic environment.	Whole zone
Note: Expressed normally as the arithmetic mean of at least 3 measurements at 1 m below surface, mid depth and 1 m above the seabed. However in water of a depth of 5 m or less the mean shall be that of 2 measurements (1m below surface and 1m above seabed), and in water of less than 3 m the 1 m below surface sample only shall apply.

8.2.3 The parameters of most concern during the demolition will be suspended solids (SS) and dissolved oxygen (DO) levels. The associated WQOs against which impacts will be assessed are as follows:

· SS levels :For demolition near Victoria Harbour Phase WCZ, human activity should not cause the natural ambient SS level to be raised by more than 30% nor give rise to accumulation of SS in the WCZ which may adversely affect aquatic communities.

· DO levels :DO levels in Victoria Harbour Phase III and Western Buffer WCZs should not be less than 2 mg 1^-1 within 2m of the seabed and above 4mg 1^-1 at an average of three water depths (1m below the water surface; mid-depth; and 1m above sea bed).

8.2.4 All discharges during the demolition of KCIP are required to comply with the Technical Memorandum for Effluents Discharged into Drainage and Sewerage Systems, Inland and Coastal Waters (TM) issued under Section 21 of the WPCO, which defines acceptable discharge limits to different types of receiving waters. Under the TM, effluents discharged into the drainage and sewerage systems, inshore and coastal waters of the WCZs are subject to pollutant concentration standards for particular volumes of discharge. The pertinent discharge limits for Victoria Harbour are shown in Appendix C of this report.

8.3 Baseline Condition

8.2.5 In order to evaluate the water quality impacts resulting from the demolition of Tsing Yi Power StationKwai Chung Incineration Plant, the water sensitive receivers (WSRs) have been identified, based on the engineering requirements, methodology, mechanical equipment and waste disposal methodology expected for the demolition works. KCIP falls within the Victoria Harbour Water Control Zone (WCZ). The EPD water monitoring location in the vicinity of the site VM13. A summary of EPD monitoring data for 1998) is given in Table 8.2. A summary of EPD monitoring data for 1999 is given in Table 8.3.

Table 8.2 Summary Statistics of 1998 Water Quality of Rambler Channel (VM13/14)

Determinant		VM13	VM14
Temperature (^oC)	Surface	23.1 (17.0 – 27.7)	23.3 (17.0 – 27.6)
Salinity (ppt)	Surface	29.5 (25.5 – 32.8)	28.5 (220.6 – 32.9)
DO (% saturation)	Surface	69 (57 – 76)	77 (66 – 93)
	Bottom	63 (46 – 73)	74 (63 – 90)
DO (mg 1^-1)	Surface	5 (4.2 – 5.7)	5.6 (4.8 – 6.6)
	Bottom	4.5 (3.3 – 5.5)	5.3 (4.4 – 6.4)
SS (mg 1^-1)	Surface	9.2 (3.0 – 17.7)	6.4 (2.9 – 10.7)
Turbidity (NTU)	Surface	5.3 (3.1 – 6.9)	4.3 (2.0 – 6.1)
PH value		7.9 (7.7 – 8.2)	8.0 (7.7 – 8.2)
BOD5 (mg 1^-1)		0.7 (0.4 – 1.1)	0.7 (0.4 – 1.2)
Ammoniacal N (mg 1^-1)		0.19 (0.03 – 0.31)	0.16 (0.03 – 0.24)
Total Kjeldahl N (mg 1^-1)		1.00 (0.06 – 0.21)	0.87 (0.35 – 1.33)
Total P (mg 1^-1)		0.11 (0.06 – 0.21)	0.09 (0.05 – 0.17)
E. coli (cfu per 100 ml)		8594 (2133 – 34000)	4163 (210 – 12667)

Table 8.3 Summary Statistics of 1999 Water Quality of Rambler Channel (VM12/14)

Determinant		VM12	VM14
Temperature (^oC)	Surface	23.3 (18.0 – 27.3)	23.6 (18.1 – 27.8)
Salinity (psu)	Surface	30.9 (26.3 – 33.3)	29.2 (20.5 – 33.1)
DO (% saturation)	Surface	71 (37 – 102)	72 (58 – 99)
	Bottom	64 (28 – 86)	68 (53 – 80)
DO (mg 1^-1)	Surface	5.1 (2.6 – 6.9)	5.2 (3.9 – 6.7)
	Bottom	4.6 (2.0 – 6.3)	4.9 (3.7 – 5.9)
SS (mg 1^-1)	Surface	12.4 (3.4 – 32.0)	8.7 (2.7 – 19.7)
Turbidity (NTU)	Surface	9.5 (5.2 – 14.9)	7.6 (3.9 – 11.2)
pH value		7.9 (7.7 – 8.2)	8.0 (7.7 – 8.2)
BOD5 (mg 1^-1)		0.9 (0.5 – 1.8)	1.1 (0.4 – 3.3)
Ammonia Nitrogen (mg 1^-1)		0.21 (0.01 – 0.34)	0.18 (0.01 – 0.35)
Total Kjeldahl N (mg 1^-1)		0.47 (0.17 – 0.72)	0.41 (0.15 – 0.67)
Total P (mg 1^-1)		0.07 (0.05 – 0.09)	0.06 (0.04 – 0.09)
E. coli (cfu / 100 ml)		7700 (4100 – 27000)	3000 (300 – 19000)

8.2.6 The Marine Water Quality in Hong Kong for 1997 (Environmental Protection Department 1998) reports the commissioning of the Stonecutters Island Sewage Treatment Works some of the sewage inputs, formerly discharged in the area, are now subject to chemically enhanced primary treatment. However the water quality closer to the sewage outfalls is generally more turbid, richer in inorganic nutrients (total nitrogen and phosphorus) and higher in E.coli and total coliforms.

8.3.3 Whereas sampling station VM13 (e.g. adjacent to the Kwai Chung Preliminary Treatment Works and the Site) is not singled out for special reference in Marine Water Quality in Hong Kong for 1997 these observations appear to be generally applicable to the area under assessment. Water quality monitoring station VM13, being close to the outfalls from Kwai Chung, is turbid and has high inorganics, E. coli and faecal coliform contents. Full compliance with the Water Quality Objectives (WQOs) for dissolved oxygen and inorganic nitrogen were recorded in VM13 and VM14 in 1997. The Marine Water Quality Hong Kong for 1999 (Environmental Protection Department 2000) reports the data VM12 and VM14.

8.3.4 According to the beneficial uses identified under Hong Kong Planning Standards and Guidelines (HKPSG), potential WSRs in Western Buffer WCZ include gazetted beaches (located >5km from the demolition site), Ma Wan Mariculture and Fishery areas (located >5km from the demolition site).

8.4 Potential Sources of Impacts

8.4.1 Potential sources of impacts upon water quality from the demolition of KCIP could include the following activities:

· Site run-off and surface water drainage containing elevated levels of SS after rainfall;

· Run-off from general demolition activities, soil decontamination procedures (including dewatering) or sewage effluents generated from the workforce.

8.5 Evaluation of Impacts

Demolition Site Run-off and Surface Water Drainage

8.5.1 Run-off and drainage from the site may contain increased loads of SS and contaminants. Potential sources of water pollution from site run-off include:

· Run-off and erosion from site surfaces, drainage channels, earth working areas and demolition stockpiles, soil remediation activities;

· Wash water from dust suppression sprays and wheel washing facilities; and

· Fuel, oil and lubricants from maintenance of on-site vehicles and equipment.

8.5.2 Demolition run-off and drainage may cause physical, chemical and biological effects on the downstream water quality in the Victoria Harbour (Rambler Channel) and Western Buffer WCZ. Although demolition run-off is considered to be small (except under heavy storm conditions), water quality impacts will become significant if the run-off and drainage are allowed to discharge directly into the receiving water body without treatment.

General Demolition

8.5.3 General demolition activities have the potential to cause water pollution as a result of debris and rubbish, concrete dust and demolished materials, entering the water column. This could result in particulates in the water column or floating refuse in the vicinity of the site that reduces the aesthetic quality of any receiving water body. Spillage of liquids, such as oil and diesel for demolition equipment, could also result in water quality impacts if they enter the soil or nearby water bodies. Details of the handling of demolition wasteC&D material to prevent such incidences are described below (see waste management).

Soil Remediation Activities

8.5.4 Soil remediation activities have the potential to cause water pollution as a result of debris from excavated materials, entering the water column. Soil remediation on site will involve the stabilisation and immobilisation of soil contaminants by mixing with cement. These activities will be similar to other excavation and concrete operations on construction sites and the potential for water pollution can be controlled using mitigation measures for construction site runoff.

8.5.5 Estimated levels of groundwater were 2m to 3m below ground level. In many cases this is below the contaminants requiring treatment however during the excavation. However it is not possible to rule out that at some locations the processes could require dewatering of the contaminated material from pits and this has been considered below.

8.5.6 Groundwater was difficult to extract from the boreholes even after heavy rain. There was no sign of any floating free products or oily residues in any groundwater samples. Observation of the groundwater extracted did not therefore indicate any contamination with petroleum oil or tar residues. Chemical analysis undertaken in the site investigation indicates that groundwater was not heavily contaminated. Therefore wherever possible it is suggested that this water is recycled on site. Water could be collected and delivered to the ash bunker for circulation for other uses on site. Potential uses could include water for mixing cement with the soils to be stabilised. It is not recommended that such water be ,used for damping down any stockpiles or , wheel-washing etc.

8.5.7 In a worst case excavation may require discharge of surplus water. and therefore the assessment has considered the Standards for Effluents discharged into marineinshore waters of the Victoria Harbour WCZ. Groundwater samples extracted from numerous boreholes across the site can be used as a general can be used to indicatore of the likely concentrations of contaminants arising from dewatering. However this approach has limitations as the chemical analyses were performed on filtered samples. Nevertheless to provide a starting point for assessment Therefore the quality of groundwater has been compared to the Standards for Effluents discharged into inshoremarine waters of the Victoria Harbour WCZ.

1.1.1During the process of gathering the groundwater samples it was noted that the quantities of groundwater accumulating in the boreholes was limited, such that it was difficult to collect sufficient water even for chemical analysis. Therefore the quantities of water likely to accumulate and require dewatering should not be excessive. In practice the manageable volumes of such liquids could be recirculated on site and would not require discharge. The accumulated liquid requiring dewatering cannot be calculated precisely at this stage, however based on professional judgement and given the likely scale of the soil remediation activities flow rates could be greater than 10m³ /day but would be unlikely to exceed 200m³/day.

8.5.8 Thus the concentrations of contaminants in groundwater have been compared to the standards. Groundwater concentrations are generallywell below the Standards for Effluents discharged into marineinshore waters of the Victoria Harbour WCZ with flow rates from above 10m³/day to below 200m³/day. The comparison is shown in Table 8.4.

Table 8.4 Comparison of Water Quality Stabndards and Groundwater Analysis

Determinant mg/L TM	Standard	Analysis Groundwater Sampling #
PH	6-10	6-10
OIL & GREASE	50	<5 (TPH)
Cyanide	0.5	<0.2mg/L
Mercury	0.1	Not detectable
Cadmium	0.1	<0.003mg/L
Other Toxic Metals (individually)	2	<0.4mg/L
Total Toxic Metals	4	<0.4mg/L
Total Phosphorus	10	<1

Table 8.4 Comparison of Water Quality Stabndards and Groundwater Analysis

Determinand TM	Standard	Analysis Groundwater Sampling #
PH	6-9	6-10
OIL & GREASE	30	<5mg/L (TPH)
Cyanide	0.1	<0.2mg/L
Mercury	0.001	Not detectable
Cadmium	0.001	<0.003mg/L
Other Toxic Metals (individually)	1	<0.4mg/L
Total Toxic Metals	2	<0.4mg/L
Total Phosphorus	10	<1

TM = As quoted in Standards for Effluents discharged into inshore waters of the Victoria Harbour WCZ

TPH = Total Petroleum Hydrocarbons

# = as summarised in Table 4.2 and presented in the Contamination Assessment Report

8.5.9 During the process of gathering the groundwater samples it was noted that the quantities of groundwater accumulating in the boreholes was limited, such that it was difficult to collect sufficient water even for chemical analysis. Therefore the quantities of water likely to accumulate and require dewatering should not be excessive. Indications are that in practice the manageable volumes of such liquids could be reused on site and would not require discharge. However the accumulation of liquid requiring dewatering cannot be calculated precisely at this stage, however based on professional judgement and given the likely scale of the soil remediation activities flow rates could be greater than 10m³ /day but would be unlikely to exceed 200m³/day.

TM = As quoted in Standards for Effluents discharged into marine waters of the Victoria Harbour WCZ

TPH = Total Petroleum Hydrocarbons

# = as summarised in Table 4.2 and presented in the Contamination Assessment Report

8.5.9 The quantities of groundwater requiring dewatering are therefore likely to be limited based on current knowledge of the ground conditions. The consultants professional judgement suggests that even in unfiltered samples the quality of the groundwater, likely to be extracted during the dewatering, would not not contain contaminants in sufficient quantity to breach the Standards for Effluents discharged into marineinshore waters of the Victoria Harbour WCZ. Much of this water can be collected and reused on site. Therefore the discharge of groundwater from dewatering would be unlikely to cause any insurmountable environmental problems. However the accumulation of liquid requiring dewatering cannot be calculated precisely at this stage and in I the event that discharge of surplus water is required, discharges from the site may require mitigation and shall be controlled as indicated below.

Sewage Effluents

8.5.10 Sewage effluents will arise from sanitary facilities provided for the on-site workforce (say 40 persons) and thus have the potential to cause water pollution. Sewage is characterised by high levels of bio-chemical oxygen demand (BOD), ammonia and E.coli counts.

8.5.11 The sewage discharges from the demolition workforce on site should be connected to the existing sewer and diverted to sewage treatment facilities that are adjacent to the KCIP. If it emerges that that no sewer connection is available during certain stages of the demolition works the installation of portable toilets and the proper disposal of workforce sewage will be necessary to ensure that discharge standards are met throughout demolition works.

Leachate

8.5.12 The possibility of leachate entering the site from the adjacent landfill has been identified as a possible source of contamination. Whereas it was difficult to extract from the boreholes nearest the even after heavy rain, there was no sign of any floating free products or leachate in any samples. Observation did not therefore give any strong indication that leachate from the landfill was entering the site and did not indicate any contamination leachate. However the possibility of leachate entering the site in groundwater cannot be ruled out. As with groundwater, wherever possible, it is suggested that this water is recycled on site as water for mixing cement. Provisions must also be made to treat surplus leachate to reduce chemical concentrations in order to comply with the standards for effluents discharged into the inshore waters of Victoria Harbour WCZ prior to disposal. It is noted that groundwater is not utilised as a potable resource in Hong Kong.

8.6 Mitigation Measures

8.6.1 It is important that appropriate measures are implemented to control run-off and drainage and, thereby, prevent high loadings of suspended solidsSS from entering the Victoria Harbour WCZ causing impacts on the identified WSRs. Proper site management is essential to minimise surface water run-off, soil erosion, soil remediation activities and the impacts of sewage effluents.

8.6.2 Site run-off and drainage should be prevented or minimised in accordance with the guidelines stipulated in the EPD Practice Note for Professional Persons, Construction Site Drainage (ProPECC PN 1/94). Reuse of water on site is to be encouraged wherever possible. Good housekeeping and storm-water best management practices, detailed as follows, shall be implemented to ensure that WPCO standards are met and that no unacceptable impacts on the WSR arise due to the demolition of KCIP. All discharges from the site shall be controlled in order to comply with the standards for effluents discharged into the Victoria Harbour WCZ under the TM.

Demolition Site Run-off and Surface Water Drainage

8.6.3 Whereas the majority of the site has a hard concrete covering the area of potentially exposed soil will be minimal. Such areas and the accumulation of dust and fine waste material shall be kept to a minimum to reduce the potential for siltation, contamination of run-off, and erosion. Run-off related impacts associated with demolition work and other general activities can be all readily controlled through the use of appropriate mitigation measures which include:

· The use of sediment traps, where appropriate; and

· The adequate maintenance of drainage systems to prevent flooding and overflow.

8.6.4 Critical areas within the Site shall be clearly marked and provided with protective measures to control site run-off. Temporary channels shall be provided to facilitate run-off discharge into the appropriate watercourses, via a silt retention pond. Permanent drainage channels shall incorporate sediment basins or traps and baffles to enhance deposition rates.

8.6.5 Temporary and permanent drainage pipes and culverts which are provided to facilitate run-off discharge shall be adequately designed for the controlled release of storm flows. All sediment traps shall be regularly cleaned and maintained. Temporarily diverted drainage shall be reinstated to its original condition when the demolition work has finished or the temporary diversion is no longer required.

8.6.6 Wheel washing facilities will be installed to ensure no earth, mud and debris is deposited on roads. Sand and silt in the wash water from such facilities shall be settled out and removed before (in line with effluent discharge standards, Appendix C) discharging the used water into storm drains. A section of the road between the wheel washing bay and the public road shall be paved with backfall to prevent wash water or other site run-off from entering public road drains.

8.6.7 Oil interception facilities should be provided in appropriate areas in the drainage system, where oil spills may occur, and regularly emptied to prevent the release of oil and grease into the storm water drainage system after accidental spillage.

8.6.8 Provided the surface run-off and drainage are effectively managed and controlled over the site, adverse water quality impacts can be avoided.

Site Run-off during Soil Remediation

8.6.9 The above mitigation shall apply generally to all excavated stockpiled materials during the soil remediation process. In practice the consultants experience suggests that, the presence of several large pits for the excavation of contaminated material will mean that any runoff from the site can be controlled is even less likely even though the hard concrete covering the is removed in places and the area of potentially exposed soil in greater than during the demolition. Surplus water arising from dewatering is to be collected on site for re-use (see below).

8.6.10 Nevertheless Tthe exposed areas and the accumulation of dust and fine waste material shall be kept to a minimum to reduce the potential for siltation, contamination of run-off, and erosion. It is recommended that the mixing of concrete with contaminated soil be carried out on a concrete covered area with bunding to control run-off, especially if heavy rain were to occur during the period while the cement sets. Bunding or sand-bagging around the excavated pits is also recommended to minimise ingress of water. However, impacts associated with this work and other general activities can be all readily controlled through the use of appropriate mitigation measures mentioned above.

General Demolition Activities

8.6.11 Debris and rubbish on site should be collected, handled and disposed of properly to prevent such material from entering the water column and causing water quality impacts. The solid waste management requirements are presented below.

8.6.12 If required, fuel storage areas should be provided with locks and be sited on sealed areas, within bunds of a capacity equal to 110% of the storage capacity of the largest container to control spilt fuel oils.

8.6.13 The effects on water quality from these demolition activities are likely to be minimal provided that site boundaries are well maintained and good site practice is observed to ensure that litter and fuels are managed, stored and handled properly.

Sewage Effluent

8.6.14 Demolition workforce sewage discharges on site should be connected to the existing sewer or sewage treatment facilities where possible. If the demolition works result in the loss of connection to the sewerage system, adequate portable chemical toilets will need to be provided by a licensed contractor who will be responsible for the proper maintenance of these facilities.

8.6.15 Assuming that either the foul sewer or portable toilets are utilised throughout the demolition works no adverse water quality impacts should arise from the demolition workforce sewage.

Contaminated Groundwater and Leachate

8.6.16 Groundwater and leachate shall be reused and mixed with cement in the immobilisation process for contaminated soils. Surplus groundwater shall be tested for metals and other pollutants for compliance with standards for effluents discharged into the Victoria Harbour WCZ under the TM. If the concentrations of contaminants exceed the standards the surplus water shall be treated.

8.6.17 Treatment methods for any surplus contaminated groundwater, such as the addition of chemicals, will precipitate out contaminants such as heavy metals. The addition of alum, lime or iron salts are commonly used processes to facilitate the sedimentation. The sludge could be combined and mixed with the cement and soils during the stabilisation process. Any floating free products can be removed using an interceptor tank by flotation. For flotation to be effective the interceptor tank must detain the fluid for an adequate period of time. The contractor shall therefore make provisions to include for treatment of surplus groundwater to reduce chemical concentrations in order to comply with the standards for effluents discharged into the inshore waters of Victoria Harbour WCZ under the TM.

8.6.16 Given that the amounts of leachate are likely to be low it is possible that limited quantities could be discharged to the foul sewer. In this case the necessary permissions and discharge licences would need to be obtained from the authorities under the relevant legislation. However the contractor shall not discharge directly or indirectly into any public sewer stormwater drain any effluent or contaminated water without the prior written consent of the site engineer in consultation with the Director of Environmental Protection (DEP). In granting this permission the DEP may require the contractor to maintain suitable works for the treatment and disposal of such effluent or contaminated water (surplus groundwater or leachate). The contractor shall therefore make provisions to include for treatment of surplus leachate to reduce chemical concentrations in order to comply with the standards for effluents discharged into the inshore waters of Victoria Harbour WCZ which should be in place before the commencement of the relevant works.

8.7 Conclusions

8.7.1 This assessment concludes that no insurmountable water quality impacts will result from the demolition work of KCIP provided that:

· All the recommended mitigation measures including appropriate drainage and silty run-off collection facilities are incorporated in accordance with the recommendations of ProPEC PN 1/94;

· The contractor shall treats any surplus groundwater to reduce chemical concentrations in order to comply with the standards for effluents discharged into the inshore waters of Victoria Harbour WCZ;

· All demolition workforce sewage is discharged either to foul sewer or to temporary portable toilets, as appropriate according to the demolition programme and methodology;

· All temporary drainage diversions will be reinstated to the original condition after the demolition works are completed and implemented properly, in accordance with the recommendations of ProPECC PN 1/94; and

· All demolition works area discharges must comply with the TM standards of the WPCO. Any practical options for the diversion and re-alignment of drainage should comply with both engineering and environmental requirements. It is considered that controls on discharges from land based demolition activities and proper site management procedures, as referenced above, will minimise residual water quality impacts to the acceptable levels stipulated in the WPCO criteria.

9 Waste Management

9.1 Introduction

9.1.1 This Section identifies the preliminary assessment of potential waste arising from the demolition of and assesses the potential environmental impacts resulting from these wastes in line with Annexes 7 and 15 of the TMEIA.

9.1.2 The options for waste minimisation, recycling, treatment, storage, collection, transport and disposal of waste arising from the demolition have been examined. Procedures for waste reduction and management are considered and mitigation measures for minimising the impacts of the wastes are recommended.

9.2 Assessment Criteria and Methodology

Assessment Criteria

9.2.1 Annexes 7 and 15 of the TMEIA provide guidance on the criteria and assessment methodology for waste impacts. Certain legislation also refers to the handling, treatment and disposal of wastes in Hong Kong and these have also been referenced for assessment criteria, including:

· Waste Disposal Ordinance (Cap 354);

· Waste Disposal (Chemical Waste) (General) Regulation (Cap 354);

· Dumping at Sea Ordinance (Cap 466);

· Crown Land (Miscellaneous Provisions) Ordinance (Cap 28); and

· Public Health and Municipal Services Ordinance (Cap 132) – Public Cleansing and Prevention of Nuisances Regulation.

9.3 Waste Disposal Ordinance

9.3.1 The Waste Disposal Ordinance (WDO) defines waste as any substance or article that is abandoned and also prohibits the unauthorised disposal of wastes. General demolition waste is not directly defined in the WDO but would be considered to fall within the category of “trade waste”. Trade waste is defined as waste from any trade, manufacturer or business, or any waste building, or civil engineering materials, but does not include animal waste and chemical waste. Asbestos containing materials should be defined as chemical waste and disposed of in line with the Code of Practice on Handling, Transportation and Disposal of Asbestos Wastes.

9.3.2 Wastes can only be disposed of at a site licensed under the WDO. A breach of these regulations can lead to the imposition of a fine (max. HK$200,000 first offence; HK$500,000 subsequent offences) and a prison sentence (max.6 months). The WDO also provides for the issuing of licences for the collection and transport of wastes. Unauthorised collection of waste (except household waste removed by occupier) is prohibited under Section 11 of WDO and is liable to a fine of HK$100,000.

9.3.3 Amendment of the WDO (Feb 1995) provides for control on movements of wastes into and out of Hong Kong through a permit system. This ties in with the requirements of the Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and their Disposal. An important requirement under the Convention is that prior notification and consents from all countries concerned are required before the commencement of any proposed shipment of hazardous waste. Any person who does anything or causes or allows another person to do anything for which a waste import and export permit is required, commits an offence and is liable to a maximum fine of HK$200,000 and six months’ imprisonment for the first offence. A maximum fine of HK$500,000 and two years’ imprisonment is applicable for a second or subsequent offence.

9.4 Waste Disposal (Chemical Waste) (General) Regulation

9.4.1 Chemical waste as defined under the Waste Disposal (Chemical Waste) (General) Regulations, includes substances such as scrap material, or unwanted substances listed under Schedule 1 of the Regulations. Such substances or chemicals so defined shall occur in such a form, quantity or concentration so as to cause pollution or constitute a danger to health or risk of pollution to the environment.

9.4.2 A person should not produce, or cause to be produced, chemical wastes unless he is registered with the EPD. Any person who contravenes this requirement commits an offence and is liable, upon conviction for a first offence, to a fine of up to HK$200,000 and to imprisonment for up to 6 months. The current fee for registration is HK$240.

9.4.3 Producers of chemical wastes must treat their wastes, utilising on-site plant licensed by EPD, or have a licensed collector take the wastes to a licensed facility. For each consignment of wastes, the waste producer, collector and disposer of the waste must utilise a trip ticket system. This system is designed to allow the transfer of wastes to be traced from ‘cradle’ to ‘grave’.

9.4.4 The Regulation prescribes the standard of storage facilities to be provided on site including labelling and warning signs. To minimise the risks of pollution and danger to human health or life, the waste producer is required to prepare and make available written procedures to be observed in the case of emergencies due to spillage, leakage or accidents arising from the storage of chemical wastes. He must also provide employees with training in such procedures.

9.5 Dumping at Sea Ordinance

9.5.1 The Dumping at Sea Ordinance stipulates the requirements for permits for dumping at sea as well as designating areas within Hong Kong waters as a marine dumping area. A person convicted of dumping without the required permits is liable to a fine of $200,000 and to imprisonment for 6 months. In the past it has been the practice to dump excavated materials at sea at designated marine dumping sites although it is not expected that any excavated materials would be generated from the demolition of KCIP.

9.6 Land (Miscellaneous Provisions) Crown Land Ordinance

9.6.1 Construction and Demolition (C&D) materials Demolition wastes which are wholly inert may be taken to public dumpsfilling areas. Public dumpsfilling areas usually form part of land reclamation schemes and are operated by the Civil Engineering Department (CED). The Crown Land Ordinance requires that dumping licences are obtained by individuals or companies who deliver suitable demolition wasteC&D materials to public dumpsfilling areas. The inert portion of Construction and Demolition (C&D) materials i.e. public fill may be disposed of at ing public filling areas, public filling barging points and public fillpublic fill stockpiling areas. The Land (Miscellaneous Provisions) Ordinance requires that dumping licences are issued to individuals or companies who deliver suitable C&D material to public filling facilities. The licences are issued by the CED under delegated powers from the Director of Lands.

9.6.2 Individual licences and windscreen stickers are issued for each vehicle involved. Under the licence conditions public dumpsfilling areas facilities will accept only inert building debris, soil, rock and broken concrete. There is no size limitation on the rock and broken concrete, and a small amount of timber mixed with other suitable material is permissible. The material should, however, be free from marine mud, household refuse, plastic, metal, industrial and chemical waste, animal and vegetable matter and any other material considered unsuitable by the dump public Ffilling area Ssupervisor.

9.7 Public Cleansing and Prevention of Nuisances By-LawsRegulation

9.7.1 Thisese By-lawsRegulation provides a further control on the illegal tipping of wastes on unauthorised (unlicensed) sites. The illegal dumping of wastes can lead to fines of up to HK$2510,000 and imprisonment for up to 6 months.

9.8 Additional Guidelines

9.8.1 There are also other documents thatwhich provide guidelines and details on how contractors should comply with the regulations. These are:

· Waste Disposal Plan for Hong Kong Planning, Environment and Lands Branch, December 1989;

· Hong Kong Planning and Standards Guidelines (HKPSG) – Chapter 9 Environment, Planning Department, 1996;

· New Disposal Arrangements for Construction Waste, Environmental Protection Department & Civil Engineering Department, 1992;

· Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes, Environmental Protection Department 1992;

· A Guide to the Control on Import and Export of Waste, Environmental Protection Department, 1996; and

· Code of Practice on the Handling, Transportation and Disposal of Asbestos Waste, Environmental Protection Department, 1993.

· Works Bureau Technical Circular No. 5/98, On Site Sorting of Construction Waste on Demolition Sites;

· Works Bureau Technical Circular No. 5/99, Trip-ticket System for Disposal of Construction and Demolition Material;

·Works Bureau Technical Circular No. 19/99, Metallic Site Hoardings and Signboards; and

·

· Works Bureau Technical Circular No. 25/99, Incorporation of Information on Construction and Demolition Material Management in Public Works Subcommittee Papers;.

· Works Bureau Technical Circular No. 29/2000 – Waste Management Plan; and

· Guidance Notes for Investigation and Remediation of Contaminated Sites of Petrol Filling Stations, Boatyards and Car Repair/Dismantling Workshops (EPD TR1/99).

9.8.2 In particular, the HKPSG provides guidelines for pollution control measures for public dumpingfilling. . These include measures provided to prevent spillage of material during unloading, to suppress wind blown dust and litter, and to prevent waste, soil and debris from being washed off the site or into the sea. WBTC 5/98 makes it mandatory to include on-site sorting, processing and disposal of C&D materials from demolition. WBTC No. 29/2000 requires contractors to prepare and implement a waste management plan.

Assessment Methodology

9.8.3 The assessment of the environmental impacts from waste generation is based on three factors:

· The type of waste generated;

· The amount of the principal waste types generated; and

· The proposed reuse, recycling, storage, transport, treatment and disposal methods, and the impacts of these methods.

9.9 Impacts of Wastes Generated from Demolition

Potential Sources of Impact

General

9.9.1 The variety of wastes generated from demolition activities can be divided into certain categories based on the constituent elements and include:

· Construction and Demolition (C&D) materials;Demolition waste;

· Chemical waste; and

· General refuse.

9.9.2 The volumes and nature of each of these waste types arising from the demolition at KCIP are discussed.

Demolition WasteC&D material

9.9.3 Demolition wasteC&D material comprises materials broken up during demolition, including concrete and structural steel. Alternatively there are materials which are surplus to requirements for the demolition process and materials which have been used and discarded. The bulk of the wastes generated in the demolition processC&D material will come from the buildings and other related structures (e.g. chimney) which are to be demolition. Demolition wasteC&D material may comprise different types of materials, including:

· bricks / masonry*;

· mortar*;

· concrete*;

· dirt / soil / mud*;

· reinforced concrete*;

· asphalt (roads, parking lots)*;

· mastic (roofs / screeding)

· plaster (drywalls) *;

· ceramic / ceiling tiles*;

· steel (girders, steel mesh, reinforcement bar, joists, trusses, window frames, railings, bannisters);

· other metal (e.g. aluminium frame);

· sheet plastics (e.g. protective covers);

· other plastics (e.g. pipes, stair handles, scaffolding ties);

· glass (e.g. window, doors);

· wood (e.g. door frame, doors, office partitioning);

· trimmings from bamboo scaffolding;

· wiring;

· white goods (appliances);

· fixtures (various material types);

· fibre (from insulation); and

· contaminants (e.g. lead based paints).

9.9.4 Those items marked with an asterisk are inert materials that are considered suitable for public dumpingfill.

9.9.5 Demolition wasteC&D materials are typically generated simultaneously in mixed form and the individual waste materials may be altered (e.g. painted). The volume and composition of C&D waste requiring disposal to landfill by the demolition at KCIP will be dependent on the demolition procedure and material recovery practices. At this stage, it is not possible to predict accurately the amount of demolition wasteC&D material that will be disposed. However, it is anticipated that the total demolition wasteC&D material arising will be in the order of 10,000 to 15,000m³ (up to 45,000 tonnes (te)). The approximate main components will be 10,000m³ concrete (85%) and steel reinforcement (15%). The steel reinforcement bars can be recycled. In addition there will be up to 52,,000m³ of asbestos waste mainly in the form of “Galbestos” (galvanised metal sheeting which forms the outer cladding on the main building). The galvanised metal cladding is coated with asbestos containing material paint and will be disposed of in line with the requirements of the APCO (Section 3).

Chemical Waste

9.9.6 Chemical Waste, as defined under the Waste Disposal (Chemical Waste)(General) Regulations, includes any substance being scrap material, or unwanted substances specified under Schedule 1 of the Regulation. EPD must be notified prior to the disposal of Part A wastes. Asbestos and dioxin wastes are classified as Part A waste under the above legislation. A complete list of such substance is provided under the Regulations, however substances likely to be generated by decommissioning of the KCIP will, for the most part, arise from the removal of ACM. It is understood that all bulk ACM at the KTIP has been removed and the remaining, mainly low risk, ACM low risk ACM will be removed prior to the demolition works or in conjunction with the main civil demolition contractor by a separate licensed Registered Asbestos Contractor. Some minor quantities of hydraulic and lubricating oils from machines involved in the demolition will also be generated.

9.9.7 The FMG of EPD have indicated that the PCDD/PCDF contaminated ash waste on the walls near the ash bunker should ideally be disposed of properly. at the Chemical Waste Treatment Centre (CWTC). The amount of PCCD/PCDF contaminated ash to be cleared up prior to demolition has been estimated to be (20m³) and since it will be pre-treated, disposal at landfill would not consume significant landfill space landfill disposal shall be considered unless the disposal criteria set by EPDFMG cannot be met (Section 4).

General Refuse

9.9.8 General refuse may include food wastes and packaging, together with waste paper which arise due to large numbers of workers who will generate a variety of general refuse materials requiring disposal.

9.9.9 The KCIP demolition site is likely to employ around say 50 to 60 workers. Estimates of general waste arising based on the numbers of workers suggest that the general refuse produced at KCIP will be in the order of 40kg/day.

Prediction and Evaluation of Impacts

General

9.9.10 The nature and amount of the waste arising from the demolition of the KCIP and the potential environmental impacts which may arise from their handling, storage, transport and disposal are discussed in detail below, under the headings of each waste type.

Demolition WasteC&D material

9.9.11 The storage, handling, transport and disposal of demolition wasteC&D materials have the potential to create visual, water, dust and associated traffic impacts.

9.9.12 The management of demolition wasteC&D materials is unlikely to raise any long term concerns because of the inert nature of most of the wastes which may, therefore, be disposed of at public dumpsfilling areasfacilities. To conserve void space at landfill sites, demolition C&D waste must not be disposed of at a landfill site if it contains more than 20% inert material by volume. It is therefore good practice to segregate wastes C&D material at demolition sites before disposing of inert materials at public dumpsfilling areas for reclamation works and other mixed C&D wastes at a controlled landfill site. The segregation and recovery of materials for recycling will also minimise C&D waste arisings requiring landfill disposal. It will also assist in minimising costs when landfill charges are introduced.

9.9.13 Construction and demolition wastes have taken up limited landfill space available in Hong Kong although the proportion has varied widely over recent years. Therefore, it is important to minimise, wherever possible, the C&D wastes being delivered to landfill. In principle, the consideration of demolition C&D wastes from the KCIP being delivered to landfill is unacceptable due to the scarcity of landfilling void resources. The major proportions of the wastes C&D materials are inert materials that can be disposed of at public dumpsfilling areas facilities (provided that segregation has been undertaken and contaminants are removed). Most of the steel would probably be recovered for recycling, the impact on space in landfills is therefore expected to be considerably lower than the total waste C&D material generated.

Chemical Waste

9.9.14 Chemical wastes may pose serious environmental and health and safety hazards if not stored and disposed of in an appropriate manner as outlined in the Waste Disposal (Chemical Waste) (General) Regulation, Code of Practice on the Handling, Transportation and Disposal of Asbestos Waste, A Guide to the Chemical Waste Control Scheme and the Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes. These hazards include:

· Toxic effects to workers;

· Adverse effects on air, water and land from spills;

· Fire hazards; and

· Disruption to sewage treatment works where waste enters the sewage system through damage to the sewage biological treatment systems.

9.9.15 Chemical wastes will arise principally as a result of the removal of any ACM cladding. An AIR and AAP are in preparation, which will assess the impacts from asbestos wastes and outlined the procedures for dealing with the remaining low risk ACM.

9.9.16 Minor quantities of chemical wastes may be generated from machines used for demolition, including hydraulic and lubricating oils. The impact of this small amount of chemical waste on the existing treatment facilities, including the Tsing Yi Chemical Waste Treatment Facility would not be sufficient to generate adverse impacts.

General Refuse

9.9.17 The storage of general refuse has the potential to give rise to adverse environmental impacts. These include odour if waste is not collected frequently (e.g. daily), windblown litter, water quality impacts if waste enters water bodies, and visual impact. The refuse may also attract pests, vermin, and other disease vectors if storage areas are not well maintained and cleaned regularly. In addition, disposal of wastes, at sits other than approved landfills, can also lead to similar adverse impacts at those sites.

9.9.18 The environmental impacts from the various waste types are summarised in Table 9.1. Due to the shortfall in public filling capacity beyond 2002, consideration should be given to separate different categories of C&D material arising from the works and recycle the inert portion such as concrete/brick tio produce aggregate etc (see 9.10.8).

Table 9.1 Summary of Waste Management Impacts

Waste Type	General Evaluation
Demolition WasteC&D material	The total quantities of demolition wasteC&D materials which will be generated will be about less than 200te day^-1, in comparison with the disposal capacity available at public dumpfilling areas, it is small. Due to the inert nature of most demolition wasteC&D material and the availability of public dump sitesfilling areas, disposal is not likely to raise long term environmental concerns.
Chemical Waste	A small volume of chemical waste, as well as asbestos containing roofing materials and louvres (preliminary .estimate., up to 210,000m^23) will be produced. Temporary storage on site, handling, transport and disposal must be in accordance with the Code of Practice on the Handling, Transportation and disposal of Asbestos Waste. Provided that this occurs, and chemical wastes are disposed of at a licensed facility, and there will be little environmental impact.
General Refuse	If good practice is adhered to and all feasible avoidance, reuse and recycling opportunities are taken, including minimising over ordering, there should be minimal impact.

9.10 Mitigation Measures

Introduction

9.9.19 This section sets out recycling, storage, transportation and disposal measures which are recommended to avoid or minimise potential adverse impacts associated with waste arisings from the demolition of the KCIP, under the headings of each waste type. The Contractor should incorporate these recommendations into a comprehensive on-site waste management plan. Such a Wwaste Mmanagement Pplan should incorporate site specific factors, such as the designation of areas for the segregation and temporary storage of reusable and recyclable materials.

Waste Management Hierarchy

9.9.20 The various waste management options can be categorised in terms of preference from an environmental viewpoint. The options considered to be more preferable have the least impacts and are more sustainable in a long term context. Hence, the hierarchy is as follows:

· Avoidance and minimisation by not generating waste through changing or improving practices and design;

· Reusing materials and therefore avoiding disposal (generally with only limited reprocessing);

· Recovery and recycling, avoiding disposal (although reprocessing may be required); and

· Ttreatment and disposal, according to relevant laws, guidelines and good practice.

9.9.21 The Waste Disposal Authority should be consulted by the Contractor on the final disposal of wastes.

9.9.22 This hierarchy should be used to evaluate waste management options, thus allowing maximum waste reduction and often reducing costs. For example, by reducing or eliminating over-ordering of materials required to undertake the demolition, waste is avoided and costs are reduced both in terms of purchasing and in disposing of wastes.

Demolition WasteC&D Mmaterials

9.9.23 At this stage a broad estimate up to 1500m³ of demolition wasteC&D materials will arise at the KCIP demolition site each month. Generation of demolition C&D waste requiring disposal at landfill(s) is estimated to be a relatively low proportion of this total. In order to minimise waste and maintain environmental impacts within acceptable levels, the mitigation measures described below should be adopted. It can also be expected that some small quantities of oil stained concrete will be generated and these will need to be treated as chemical waste for disposal purposes and appropriate measures are described.

9.9.24 In accordance with the New Disposal Arrangement for Construction Waste, Environmental Protection Department, 1992, disposal of demolition wasteC&D material can either be at a specified landfill, or at a public dump filling facility with the latter being the preferred option. However demolition wasteC&D materials currently comprise a high proportion of C&D waste inputs to landfills and in order to maximise landfill life, Government policy prohibits the disposal of demolition wasteC&D material to landfill if it contains more than 20% inert material by volume. Such inert wastes are directed to reclamation areas, where they have the added benefit of offsetting the need for removal of materials from terrestrial borrow areas for reclamation purposes. In the same way that materials which may be recycled should be segregated from other wastes, clean inert waste, suitable for disposal at public dump sitesfilling areas, should be segregated from any ‘contaminated’ wastes which will require landfill disposal.

9.9.25 The Contractor should recycle demolition wasteC&D material on-site as far as possible. Planning, careful design and good site management of the demolition process can minimise over ordering and avoidable waste. Areas within the Site areas can be segregated for the separation and storage. Proper segregation of wastes on site will increase the feasibility of utilising recycling contractors to recycle certain components of the waste stream. Concrete and masonry can be crushed and used as fill to level the site after demolition. However there will be little or no excavation of any underground structures therefore the majority of inert waste will need to be delivered to public dumpsfilling areas. Steel reinforcing bars can be re-used by scrap steel mills.

9.9.26 If landfill disposal has to be used, the C&D wastes will most likely be delivered to the WENT Landfill or SENT Landfill. Government is currently studying the possibilities of introducing a pilot C&D waste recycling facility which would offer another alternative if it were in operation by the time demolition for KCIP takes place.

9.9.27 At preseThe provisions of WBTC No. 5/98 (On Site Sorting of Construction Waste on Demolition Sites) shall be followed. At present, Government is developing a charging policy for the disposal of C&D waste to landfill. When it is implemented, this will provided additional incentive to reduce the volume of waste generated and hence encourage the appropriate sorting and segregation of different types of demolition wasteC&D material. .

Chemical Waste

9.10.8 For those processes that generate chemical waste, it may be possible to find alternatives that generate reduced quantities or even no chemical waste, or less dangerous types of chemical waste.

9.10.9 Chemical waste that is produced, as defined under section 3 by Schedule 1 of the Waste Disposal (Chemical Waste) (General) Regulation, should be handled in accordance with the Code of Practice on the Packaging, LabellingHandling and Storage of Chemical Wastes as follows.

9.10.10 Containers used for the storage of chemical wastes should:

· Be suitable for the substance they are holding, resistant to corrosion, maintained in a good condition, and securely closed;

· Have a capacity of less than 450 l unless the specifications have been approved by the EPD; and

· Display a label in English and Chinese in accordance with instructions prescribed in Schedule 2 of the Regulations.

9.10.11 The storage area for chemical wastes should:

· Be clearly labelled and used solely for the storage of chemical waste;

· Be enclosed on at least 3 sides;

· Have an impermeable floor and bunding, of capacity to accommodate 100% of the volume of the largest container or 20% by volume of the chemical waste stored in that area, whichever is the greatest;

· Have adequate ventilation;

· Be covered to prevent rainfall entering (water collected within the bund must be tested and disposed as chemical waste if necessary); and

· Be arranged so that incompatible materials are adequately separated.

9.10.12 Disposal of chemical waste should:

· Be via a licensed waste collector; and

· Be to a facility licensed to receive chemical waste, such as the Chemical Waste Treatment Facility which also offers a chemical waste collection service and can supply the necessary storage containers; or

· Be to a recycling or reprocessing facility , licensed by EPD.

9.10.13 The BusinessCentre for Environment Centreal Technology operates a Waste Exchange Scheme that which can assist in finding receivers or buyers.

9.10.14 Asbestos waste that is produced should be handled in accordance with the Code of Practice on the Handling, Transportation and Disposal of Asbestos Wastes. The detailed requirements will be presented in the Asbestos Study Report.

9.10.15 The FMG of EPD have indicated that the PCDD/PCDF contaminated ash waste (20m³ approx.) on the walls near the ash bunker could be disposed of at the Chemical Waste Treatment Centre (CWTC). However treatment on-site prior to disposal at a landfill should be considered. However due to the small quantity involved (20m³) landfill disposal is appropriate. This material must be removed by an appropriately qualified specialist contractor and must be collected, deposited at landfill in accordance with criteria and conditions as specified in agreement with Facilities Management Group of EPD (Appendix D). As a fall back option the materials can be transported to the CWTC for disposal if the landfill criteria cannot be met. No PCDD/PCDF were detected above the USEPA criterion at any other locations in soil samples. Remedial action will be required to clean up these materials prior to the demolition. The material that is contaminated is deposited on the walls. As such, there is no opportunity for in-situ containment or treatment of this material in the context of the ultimate redevelopment of the site. Therefore, there is no alternative but to dispose of this material offsite. This should be undertaken prior to the demolition of any structures (Section 4).

General Refuse

9.10.16 General refuse should be stored in enclosed bins or compaction units separate from demolition and chemical wastes. A reputable waste collector should be employed by the Contractor to remove general refuse, separately from demolition C&D material and chemical wastes, preferably daily or every second day to minimise odour, pest and litter impacts. The burning of refuse on construction sites is prohibited by law.

9.10.19 General refuse is generated largely by food service activities on site, so reusable rather than disposable dishware should be used if feasible. Aluminium cans are often recovered from the waste stream by individual collectors if they are segregated or easily accessible, so separate, labelled bins for their deposit should be provided if feasible.

9.10.20 Office wastes can be reduced through recycling of paper if volumes are large enough to warrant collection. Participation in a local collection scheme should be considered if one is available.

Storage areas for different waste types

9.10.21 Different types of waste should be segregated and stored in different containers, skips or stockpiles to enhance reuse or recycling of materials and their proper disposal.

9.10.22 An on-site temporary storage area should also be provided.

Trip-ticket system

1.1.1 In order to monitor the disposal of C&D and solid wastes at public filling facilities and landfills, and control fly-tipping, a trip-ticket system (Works Bureau Technical Circular No. 5/99, Trip-ticket System for Disposal of Construction and Demolition Material) should be included as one of the contractual requirements and implemented under the supervision of the Environmental Team .

9.10.23 The system should be subject to independent auditing.

Training and Records of wastes

9.10.24 A waste management plan will be requited under Works Bureau Technical Circular No. 29/2000. This should include a description of the training proposed to educate the workforce on the requirements of the Waste Disposal Ordinance, subsidiary legislation and guidelines listed above. The training should include as a minimum, arrangements for waste management. On Site Sorting of Construction Waste on Demolition Sites (WBTC No. 5/98), Trip-ticket System for Disposal of Construction and Demolition Material (WBTC No. 5/99).

9.10.25 A recording system for the amount of wastes generated, recycled and disposed (including the disposal sites) should be proposed.

Waste Management Requirements

9.10.26 This section describes waste management requirements and provides practical actions which can be taken to minimise the impacts arising as a result of the generation, storage, handling, transport and disposal of wastes. A Waste Management Plan will be required for all stages of the demolition and soil remediation works in line with Works Bureau Technical Circular No. 29/2000.

9.10.27 Waste reduction is best achieved at the planning and design stage, as well as by ensuring that processes are run in the most efficient way. Good management and control can prevent the generation of significant amounts of waste. For unavoidable wastes, reuse, recycling and optimal disposal are most practical when segregation occurs on the demolition site, as follows:

· Demolition wastePublic fill (inert) for disposal at public dumpfilling areas;

· Demolition C&D waste (non-inert) for landfill;

· Chemical waste for treatment at licensed facilities; and

· General refuse for disposal at landfill.

9.10.28 The criteria for sorting solid waste is described in New Disposal Arrangements for Construction Waste, Environmental Protection Department and Civil Engineering Department, 1992 and Works Bureau Technical Circular No. 5/98, On Site Sorting of Construction Waste on Demolition Sites. Waste C&D material containing in excess of 20% by volume of inert materials should be segregated from C&D waste with a larger proportion of putrescible material. In preference the inert materials shall be directed to the proposed Pilot C&D Waste Recycling Facility at Kai Tak and after early 2005 excess materials could be directed to the adjacent proposed public fillpublic filling barging point on Area 30D.

9.10.29 Proper storage and site practices will minimise the damage to, or contamination of, demolition C&D materials that may reduce their recyclability and suitability for disposal in public dumpsfilling areas. On site measures may be implemented which promote the proper disposal of wastes once off-site. For example having separate skips for inert (rubble, sand, stone, etc) and non-inert (wood, organics, etc) wastes materials would help to ensure that the former are taken to public dumpsfilling areas, while the latter are properly disposed of at controlled landfills. Since waste public fill brought to public dumpsfilling areas will not attract a charge, while that C&D waste taken to landfill may attract some charge in the future, separating waste C&D material may also help to reduce waste disposal costs, should landfill charging be introduced.

9.10.30 Specifically, it is recommended that:

· Wastes should be handled and stored in a manner which ensures that they are held securely without loss or leakage thereby minimising the potential for pollution;

· Only reputable waste collectors authorised to collect the specific category of waste concerned should be employed;

· Appropriate measures should be employed to minimise windblown litter and dust during transportation by either covering trucks or transporting wastes in enclosed containers;

· The necessary waste disposal permits should be obtained from the appropriate authorities, if they are required, in accordance with the Waste Disposal Ordinance (Cap 354), Waste Disposal (Chemical Waste) (General) Regulation (Cap 354) and the Government Land Ordinance (Cap 28);

· Collection of general refuse should be carried out frequently, preferably daily;

· Waste should only be disposed of at licensed sites and site staff and the civil engineering Contractor should develop procedures to ensure that illegal disposal of wastes does not occur;

·Waste storage areas should be well maintained and cleaned regularly; and

Records should be maintained of the quantities of wastes generated, recycled and disposed, determined by weighing each load.

9.11 Waste Management Planning

9.11.1 A Waste Management Plan (WMP) will be required for all stages of the demolition and soil remediation works and shall include the findings and recommendations of the waste management section of the EIA. The WMP shall include, but not necessarily be limited to, details on the types, quantities, disposal methods, timings and locations for disposal of wastes, responsibilities for implementation and possible recycling and reuse of materials.

1.1 EM&A Requirements

1.1.1It is recommended that auditing of each waste stream, including any waste arising from the decontamination of soils and the remediation procedures should be carried out periodically by the EM&A Team to determine if wastes are being managed in accordance with approved procedures. The audits should look at all aspects of waste management including waste generation, storage, recycling, treatment, transport, and disposal. An appropriate audit programme would be to undertake a first audit at the commencement of the demolition works, and then to audit quarterly thereafter.

1.1.1It is likely that relatively small quantities of demolition C&D materials will require disposal at landfill. The bulk of the demolition wasteC&D materials will be disposed at public dumpsfilling areas and some, in particular reinforcement bar, will be recycled. Limited quantities of chemical wastes (mainly asbestos) and general wastes will be generated. Mitigation measures relating to good practice have been recommended to ensure that adverse environmental impacts are prevented and that opportunities for waste minimisation and recycling are followed.

Provided that the recommendations are thoroughly implemented the storage, handling, collection, transport, and disposal of wastes arising from the demolition of KCIP will be in full compliance with the regulatory requirementsFramework for the Waste Management Plan

9.11.2 The WMP shall be prepared in accordance with WBTC No. 29/2000 and shall provide details of the measures and procedures considered necessary to control and manage the storage, transportation and disposal of all wastes generated during the demolition and the main provisions of the WMP will include:

· reference to statutory waste management requirements and obligations;

· reference to waste management requirements as determined under the EIA and Environmental Permit;

· clarification of responsibilities within the environmental management structure;

· clarification of the types, quantities, disposal methods and likely timing of waste arising;

· provisions for sorting facilities on site to facilitate sorting of C&D material;

· proposals for recycling, reuse and return of C&D material;

· details of waste handling procedures;

· details of waste transportation procedures;

· details of waste disposal procedures; and

· details of auditing and other checking requirements.

9.10.31 The WMP shall confirm the responsibilities of the Contractor to establish methods for the avoidance of waste and opportunities for reuse and recycling. The WMP shall also provide details on the practice to be adopted to ensure avoidance of waste and that reuse and recycling opportunities are taken. This will include minimising over ordering. There will however be generation of significant amounts of C&D waste.

9.10.32 The Contractor shall propose to reuse, recycling and optimise disposal by segregating waste and ensuring that public fill (inert) is referred for disposal at public filling areas, C&D waste (non-inert) is transferred for disposal at landfill, chemical waste is collected and dispatched for treatment at licensed facilities; and that general refuse is collected and transferred for disposal at landfill.

9.10.33 The WMP proposed by the Contractor shall include the recommendations from the EIA. The WMP shall include site specific factors, such as the designation of areas for the segregation and temporary storage of reusable and recyclable materials. The WMP shall also propose a recording system for the amount of wastes generated, recycled and disposed (including the disposal sites).

9.10.34 The WMP shall confirm the estimated total quantities of C&D materials that will be generated (currently estimated at less than 200te day^-1) in comparison with the disposal capacity available at public filling areas). The WMP shall re-establish the availability of public filling areas and confirm the location(s).

9.10.35 The WMP shall confirm the estimated total quantities of chemical waste and the route of disposal at a licensed facility. Quantities of asbestos waste, including asbestos containing roofing materials and louvres (currently estimated at up to 2,000m³) shall be confirmed. The WMP shall detail the temporary storage arrangement on site for handling, transport and disposal of asbestos waste that must be in accordance with the Code of Practice on the Handling, Transportation and disposal of Asbestos Waste.

9.10.36 The WMP shall detail the provisions for monitoring the disposal of C&D and solid wastes at public filling facilities and landfills. To control fly-tipping, a trip-ticket system (Works Bureau Technical Circular No. 5/99, Trip-ticket System for Disposal of Construction and Demolition Material) shall be included as one of the contractual requirements and implemented under the supervision of the Environmental Team. The system should be subject to independent auditing.

9.10.37 The WMP shall include a description of the training proposed to educate the workforce on the requirements of the Waste Disposal Ordinance, subsidiary legislation and guidelines. The training should include as a minimum, arrangements for waste management, references to On Site Sorting of Construction Waste on Demolition Sites (WBTC No. 5/98) and the Trip-ticket System for Disposal of Construction and Demolition Material (WBTC No. 5/99).

EM&A Requirements

9.10.38 It is recommended that auditing of each waste stream, including any waste arising from the decontamination of soils and the remediation procedures should be carried out periodically by the EM&A Team to determine if wastes are being managed in accordance with approved procedures. The audits should look at all aspects of waste management including waste generation, storage, recycling, treatment, transport, and disposal. An appropriate audit programme would be to undertake a first audit at the commencement of the demolition works, and then to audit quarterly thereafter.

9.10.39 It is likely that relatively small quantities of C&D materials will require disposal at landfill. The bulk of the C&D materials will be disposed at public filling areas and some, in particular reinforcement bar, will be recycled. Limited quantities of chemical wastes (mainly asbestos) and general wastes will be generated. Mitigation measures relating to good practice have been recommended to ensure that adverse environmental impacts are prevented and that opportunities for waste minimisation and recycling are followed.

9.10.40 Provided that the recommendations are thoroughly implemented the storage, handling, collection, transport, and disposal of wastes arising from the demolition of KCIP will be in full compliance with the regulatory requirements.

10 Environmental Monitoring and Audit

10.1 Introduction

10.1.1 In this section recommendations for the environmental monitoring and audit (EM&A) programme for the demolition of the KCIP are outlined in this section, taking account of the findings of the EIA. A dedicated EM&A programme, based on the recommendations of the Generic Environmental Monitoring and Audit Manual, Environmental Protection Department, May 1996, has been prepared as a separate EM&A Manual Report in line with Annex 21 of the TMEIA.

10.2 Requirement for EM&A

10.2.1 This EIA has identified that noise and dust impacts will be moderate but some monitoring for dust is proposed as a proactive measure and an EM&A manual is required under the SB.

10.2.2 Monitoring of the removal and disposal of any contaminated materials, as required based on the soil contamination assessment and Site Investigation Report is required to be included in the EM&A Manual,

10.2.3 With respect to air quality the provisions of the Air Pollution (Construction Dust) Regulation will ensure that sensitive receivers are not impacted by the demolition impacts. Likewise noise assessments have indicated that the sensitive receivers will be too far from the demolition procedures to be affected.

10.2.4 However, it is recognised that a proactive approach to EM&A is preferred and although statutory criteria are not expected to be exceeded, it is proposed that one air monitoring monitoring and one noise monitoring location be included. This would allow checking on demolition contractors performance and facilitate a proactive approach, rather than a solely reactive approach based only on monitoring of complaints.

10.3 Environmental Monitoring and Audit

10.3.1 It is recommended that the project Proponent (CED) should provide suitably qualified staff to carry out the recommended EM&A programme. The Proponent’s and the Contractor’s responsibilities will be related through the application of Event Contingency Plans (ECPs) to deal with any exceedance of the established criteria, either in the course of normal working or through unforseen circumstances.

10.3.2 An Environmental Team (ET) shall be appointed which meets EPDs criteria, to implement and supervise the monitoring activities as specified in the EM&A Manual. All activities will comply with all prevailing environmental legislation (Air, Noise, Water and Waste) as well as not to cause any land contamination.

10.3.3 EM&A to be undertaken during the demolition of the KCIP will have the following overall objectives.

· To monitor the performance of the project and to provide an early indication if any of the environmental mitigation measures, identified in this report and/or implemented by the Contractor, fail to meet the established standards and guidelines;

· To take remedial action if unexpected problems or unacceptable impact arise;

· To provide data to enable an environmental audit to be undertaken;

· To provide a data base against which the short or long term environmental effects associated with the demolition works may be determined; and

· To verify the environmental impacts predicted in the EIA.

10.3.4 The monitoring will be undertaken by Proponent’s site staff under the direction of an environmental professional with 7 years’ experience (environmental) and will consist of:

· 1-hour and 24-hour TSP monitoring at one locations on the boundary facing west;

· monitoring of backfilling of the Ash Bunker and Refuse Reception Bunkers with uncontaminated material as required;

· noise monitoring at one locations near the site boundary facing west (Kwai Chung Preliminary Treatment Works); and

· complaints monitoring.

10.3.5 In order that the environmental monitoring may be audited, the Proponent will establish strict procedures and protocols for carrying out, recording and reporting this work in the tender requirements, in line with the final EM&A manual. An Independent Checker (Environmental) shall be appointed by the proponent to check that the EM&A reporting is in line with the EM&A event action planning requirements.

10.4 Event ContingencyContingency Plans

10.4.1 ECP are provided in the EM&A Manual. The purpose of the EACPs is to provide procedures for ensuring that if any deterioration of environmental quality occurs as a result of the demolition works, in association with the monitoring and audit activities. Such deterioration may occur either accidentally or through inadequate implementation of mitigation measures on the part of the contractor. The procedures are established to ensure that the causes are quickly identified and remedied, and that the risk of a similar events re-occurring is reduced.

10.4.2 The ECPECPs are based is the prescription of procedures and actions associated with the measurement of certain defined levels of pollution by environmental monitoring, established prior to the commencement of the works. These are:

· Action Level, beyond which appropriate remedial actions may be necessary to prevent environmental quality deteriorating further ; and

· Limit Level, the limits stipulated in the relevant Hong Kong statutes and guidelines, if these are exceeded, works should not proceed without appropriate remedial action, including a critical review of plant and working methods.

10.5 Implementation Schedule

10.5.1 The EM&A manual and the EIA will include an implementation schedule for mitigation measures in the form of a checklist as required under the Study Brief.

10.6 Reporting

10.6.1 Monthly Reports will be produced as part of the EM&A programme throughout the life of the project. EM&A Reports may include a brief account of construction activities during the month, an interpretation of the significance of the monitoring results by verifying compliance. Failures to comply with the target levels would be featured and an account of any necessary remedial measures recommended by the Proponents’ site staff and implemented by the Contractor would be included.

Table 10.1 Schedule of Impacts and Mitigation Measures

No.	Activity	Mitigation/EIA Recommendations	Respons-ibility for Implemen-tation	Location Duration completion Of measures	Implemen-tation Stage	Relevant Guidelines Legislation
1	Ash Disposal
I	Treatment	Reconfirm extent of contaminated ash deposits by sampling and analysis for dioxins and furans. Handling, transportation and disposal of the ash waste in line with relevant regulations. Collection, immobilisation and testing of waste for disposal to landfill shall be carried out according to the relevant regulations and recommendations of the EIA including immobilisation by collection and mixing the ash material with cement. Pilot mixing and TCLP tests should establish the ratio of cement to ash to the satisfaction of EPD. Ash waste to be treated and placed into steel drums lined with plastic sheeting. The drums should be adequately sealed and in new or good condition. Prior agreement of the disposal criteria from EPD and agreement to disposal from the landfill operator must be obtained..	CED’s Contractor	KCIP work areas. Duration of the ash removal	A@	1, 10, EIA
II	Disposal	To monitor the disposal of waste at landfills, a “trip-ticket” system (WBTC No. 5/99) for all solid waste transfer/disposal operations should be implemented. The system should be included as a contractual requirement, and monitored by the Environmental Team and audited by the Independent Checker (Environment).	CED’s Contractor	As above	A	1, 5, 9
III	Asbestos Removal	An asbestos abatement programme should be submitted to EPD for approval prior to the commencement of the asbestos abatement work.Remove residual ACM in line with AIR and AAP submitted under APCO	CED and Contractor	As above	A	4
2	Demolition
A1	Non-blasting Methodology	Waste Management Plan to be submitted to EPD. Demolition by Non-Blasting Methodology Only. All structures and buildings should be demolished and removed prior to demolition of chimneys	CED	KCIP work areas. Duration of the demolition	C#	8
A2	Waste Management Plan.	A Waste Management Plan shall be submitted to EPD for approval. The Waste Management Plan shall include, but not be limited to, the findings of the Waste Management Paper of the EIA, the types, quantities, disposal methods, timing, locations of final disposition, responsibilities for implementation and the possible recycling and reuse of wastes generated.	CED and Contractor	Prior to commencement of the demolition works	Prior to C#	1
B	Material Storage	Covers for dusty stockpiles and control of dust emissions from construction (demolition) works requires appropriate dust control measures to be implemented in accordance with the requirements in the Air Pollution Control (Construction Dust) Regulation.	CED’s Contractor	KCIP work areas. Duration of the demolitionAs above	C	4
C	Vehicle movement	Haul road watering, vehicle wheel wash prior to exit. Where practical, access roads should be protected with crushed gravel.	CED’s Contractor	As above	C	4
D	Plant maintenance	All plant shall be maintained to prevent any undue air emissions.	CED’s Contractor	As above	Prior to start of works	4
E	Demolition Techniques	Selection of non-blasting demolition techniques to minimise noise and vibration.	CED’s Contractor	As above	C	8
F	Plant maintenance	All plant shall be maintained to prevent any undue noise nuisance.	CED’s Contractor	As above	C	2, 3
G	Wheel wash	All wheel wash water shall be diverted to a sediment pit.	CED’s Contractor	As above	C	5
H	Sediment control	Sediment removal facilities shall provided and be maintained and excavated as necessary to prevent sedimentation of channelsthe channel. Perimeter channels should be provided. Works should be programmed for the dry season where feasible. Environmental guidelines for the handling and disposal of discharges from construction sites, as stipulated in the Practice Note for Professional Persons, Construction Site Drainage (ProPECC PN 1/94) to be followed.	CED’s Contractor	As above	C	5, 12
I	Surface water diversion	All clean surface water shall be diverted around the site.	CED’s Contractor	As above	C	5, 12
J	Fuel can storage	All fuel cans shall be placed within a bunded area. Any fuel spills shall be mopped up as necessary.	CED’s Contractor	As above	C	5,6
K	Material, plant move-ment & fuel can filling.	Any fuel or oil spills shall be excavated and disposed of.	CED’s Contractor	As above	C	6,7
L	Generators	All generators shall be placed within a bunded area. Any fuel spills shall be mopped up as necessary.	CED’s Contractor	As above	C	5,6,7
M	Material containers	All empty bags and containers shall be collected for disposal.	CED’s Contractor	As above	C	6,7
N	Worker generated litter and Waste	Litter receptacles shall be placed around the site. Litter shall be taken regularly to the refuse collection points. Chemical toilets (or suitable equivalent) should be provided for workers. Any canteens should have grease traps.	CED’s Contractor	As above	C	6
O	Neighbourhood nuisance	All complaints regarding construction works shall be relayed to the environmental team.	CED’s Contractor	As above	C	1, 6
P	Legal requirements	Different types of waste should be segregated, stored, transported and disposed of in accordance with the relevant legislative requirements and guidelines	CED’s Contractor	As above	C	1,6
Q	On-site separation	On-site separation of municipal solid waste and construction/demolition wastes shallould be conducted as far as possible in order to minimise the amount of solid waste to be disposed to landfill.	CED’s Contractor	As above	C	1, 11
R	Temporary storage area	Separated wastes should be stored in different containers, skips, or stockpiles to enhance reuse or recycling of materials and encourage their proper disposal.	CED’s Contractor	As above	C	1, 11
S	Record of wastes	Records of quantities of wastes generated, recycled and disposed (with locations) shall be kept.	CED’s Contractor	As above	C	1, 9
T	Trip-ticket system	To monitor the disposal of waste at landfills and control fly-tipping, a “trip-ticket” system under WBTC N0.5/99 for all solid waste transfer/disposal operations should be implemented. The system should be included as a contractual requirement, and monitored by the Environmental Team and audited by the Independent Checker (Environment).	CED’s Contractor	As above	C	1, 9
3	Soil Remediation Phase
U	B, C, D, F, G, I, J, K, L, M, N, O, P, Q, R, S and T as above	As above (see W for soil remediation).	As above	As above	R	As above
V	De-watering	Collect and recycle extracted groundwater and leachate by mixing with cement for soil remediation. Environmental guidelines for the handling and disposal of discharges from construction sites, as stipulated in the Practice Note for Professional Persons, Construction Site Drainage (ProPECC PN 1/94) to be followed. Any surplus groundwate and leachate requiring disposal to be disposed of under the relevant legislation or treated to meet the standards given in Table 9a of the WPCO TM and other parameters to be agreed with EPD prior to any consent being given to duischarge.	CED’s Contractor	KCIP work areas. Duration of the soil remediation	R	5
W	Immobilisation	Immobilisation and testing of waste soil shall be carried out according to the relevant regulations and recommendations of the EIA including immobilisation by collection and mixing the contaminated soil material with cement. Pilot mixing and TCLP tests should verify the effectiveness and establish the ratio of cement to soil to the satisfaction of EPD. Such activities shall take place in a covered area with a concrete paved floor. Reassurance confirmatory sampling shall be carried out to confirm the extent of contamination. Soil waste to be cast in blocks and replaced in the ground. Extracted soils and materials and stabilisation/solidification to be conducted in bunded area to prevent surface run-off. See also item 2(H) above. Final soil decontamination report to be submitted to EPD.	CED’s Contractor	As above	R	1, 10
4	Monitoring and Audit	To be carried out in accordance with the Schedule in the EM&A Manual.	CED*/ Contractor/ RSS	KCIP works areas During demolition and at end of demolition throughout execution of Remediation Action Plan	C	1

* Normally undertaken by a specialist monitoring team employed directly by the proponent and audited by the Independent Checker (Environment)al Works Checker

@ A = during ash removal (before demolition)

# C = during construction (i.e. demolition phase).

* R = during soil remediation phase (after demolition)

1. Environmental Impact Assessment Ordinance Technical Memorandum (EIAO) 2. Noise Control Ordinance 3. The ProPECC Note PN2/93 (Construction Noise daytime limits) 4. Air Pollution Control Ordinance (APCO) 5. Water Pollution Control Ordinance (WPCO)(Cap. 358) 6. Waste Disposal Ordinance (Cap 354) 7. Waste Disposal (Chemical Waste)(General) Regulation (Cap 354)

8. Draft Code of Practice on Demolition of Buildings (BD, 1998) 9. Works Bureau Technical Circular No. 5/99, Trip-ticket System for Disposal of Construction and Demolition Material 10. Guidance Notes for Investigation and Remediation of Contaminated Sites 11. Works Bureau Technical Circular No. 5/98, On Site Sorting of Construction Waste on Demolition Sites 12. ProPECC Note PN 1/94Construction Site Drainage

12. Environmental Impact Assessment Ordinance Technical Memorandum (EIAO)

12. Noise Control Ordinance

12. The ProPECC Note PN2/93 (Construction Noise daytime limits)

12. Air Pollution Control Ordinance (APCO)

12. Water Pollution Control Ordinance (WPCO)(Cap. 358)

12. Waste Disposal Ordinance (Cap 354)

12. Waste Disposal (Chemical Waste)(General) Regulation (Cap 354)

12. Draft Code of Practice on Demolition of Buildings (BD, 1998)

12. Works Bureau Technical Circular No. 5/99, Trip-ticket System for Disposal of Construction and Demolition Material

12. Guidance Notes for Investigation and Remediation of Contaminated Sites

12. Works Bureau Technical Circular No. 5/98, On Site Sorting of Construction Waste on Demolition Sites

12. ProPECC Note PN 1/94Construction Site Drainage

11 Conclusions and Recommendations

11.1 Overview

11.1.1 In this Section the overall recommendations of the EIA are summarised based on the assessments and conclusions presented in the preceding chapters. A preferred demolition methodology and soil remediation action plan has been proposed. The mitigation measures proposed to control noise, dust and water quality impacts in the demolition phase should be carried forward to the decontamination phase.

11.1.2 The demolition of a municipal incinerator constitutes a designated project under the provisions of the Environmental Impact Assessment Ordinance (EIAO). The Kwai Chung Incineration Plant (KCIP) has been decommissioned. A study brief (ESB024/98) for the EIA of the demolition of KCIP was issued by EPD under the EIAO in December 1998. CED subsequently compiled a Study Brief (SB) for consultants to follow for this Study (Environmental Impact Assessment for the Demolition of the KCIP as part of Agreement No. CE 15/99) which includes the requirements of ESB024/98.

11.2 Demolition Methodology

11.2.1 In order to satisfy the requirements of the EIA it is necessary to define the nature of the works involved in the demolition. Prior to this report a Preferred Demolition Methodology for above ground structures was presented and endorsed by the proponent (1st December 1999). The summary of the Preferred Demolition Methodology is presented and the conclusion is that non-explosive demolition methods should be used for the demolition remaining structures at Kwai Chung Incinerator PlantKCIP.

11.3 Asbestos.

11.3.1 The operation of the KCIP has not given rise to any residual contamination with asbestos containing materials (ACM) dust or fibre. However there is some remaining ACM which will require removal before the buildings and chimney are demolished, but these are not currently hazardous to the public or staff as they are not accessible. Experience suggests that in practice the removal of asbestos materials in certain locations may run more smoothly if asbestos is removed at the time of the demolition such that asbestos contractors and civil demolition contractors work in tandem. However where possible asbestos materials shall be removed from a given area prior to demolition in that area. Further dovetailing of asbestos abatement works with general of demolition may be necessary at the detailed design stage. The asbestos investigation and abatement plans are described in detail in the dedicated Asbestos Study Report, AIR and AAP submitted under the APCO.

11.4 Land Contamination and Remediation.

11.4.1 The Contamination Assessment is based on the results of a detailed Site Investigation, including the collection of sub-surface samples and chemical analyses has indicated that the levels of contamination are above the criteria at which remediation is required in some locations. Some localised areas of ground contamination have been identified across the KCIP site. Where contaminants have been detected above the “Dutch B Levels” criterion, clean up has been proposed. Whereas the site cannot be considered as uncontaminated, in all but a few cases the contamination is persistent and immobile (e.g. heavy metals). The entire site is currently paved in thick concrete and viable exposure pathways are minimal. In the context of the current EIA study, it is considered that the possibilities for contact with ground contaminants during the demolition of KCIP are relatively low. This is because ground excavations will not be necessary at that stage. The possibilities for contact with ground contaminants during the soil remediation phase are limited to site workers and are also are relatively low, provided appropriate precautions are implemented. A Remediation Action Plan has been proposed, in line with Government policy.

11.5 Landfill Gas Hazard Assessment

11.5.1 Qualitative landfill gas hazard assessment has been undertaken in accordance with the Landfill Gas Hazard Assessment Guidance Note issued by EPD. Since demolition works will be undertaken above ground level and in the open air they are not considered unduly susceptible to hazards caused by the accumulation of landfill gas. Intrusive ground investigations have been completed following recommendations made to ensure that all sub-surface works were conducted under safe and controlled conditions. These recommendations for safe site practice should be carried forward to the soil remediation phase after the demolition to ensure that all future sub-surface works are also conducted under safe controlled conditions. All demolition and associated works can be completed and the risk of landfill gas hazard can be controlled to acceptable levels by the implementation of a gas monitoring programme as necessary.

11.6 Noise

11.5.2 Noise impacts will not require mitigation. However a proactive approach to EM&A is preferred and although no exceedances of statutory criteria are predicted, it is proposed that one noise monitoring location be included as a a watching brief be adopted in line with proactive measure principles.

11.6 Air Quality.

11.6.1 Statutory control of dust emissions from construction (demolition) works requires appropriate dust control measures to be implemented during the construction stage in accordance with the requirements in the Air Pollution Control (Construction Dust) Regulation. Using the measures and requirements in the Air Pollution Control (Construction Dust) Regulation, the dust nuisance to the surrounding air sensitive receivers can be minimised. With such mitigation, the predicted dust levels at the ASRs will be within the established criteria, therefore excessive dust during demolition works is not expected. In addition, as a proactive measure, the Environmental Monitoring and Audit (EM&A) for dust generated during the demolition is also recommended at the site boundary at the west to ensure that the dust criteria will not be exceeded at the Kwai Chung PTW. EM&A for dust is recommended at the site boundary to ensure that the dust criteria will not be exceeded and as a proactive measure and to ensure that local nuisances do not ariseStatutory control of dust emissions from construction (demolition) works requires appropriate dust control measures to be implemented during the construction stage in accordance with the requirements in the Air Pollution Control (Construction Dust) Regulation. With such mitigation, the predicted dust levels at the ASRs will be within the established criteria, therefore excessive dust during demolition works is not expected. EM&A for dust is recommended at the site boundary to ensure that the dust criteria will not be exceeded and as a proactive measure and to ensure that local nuisances do not arise.

11.7 Water Quality.

11.7.1 Water quality impacts will require mitigation in line with the Water Pollution Control Ordinance (WPCO) but impacts can be controlled within the established criteria by the use of established and routine site run off control techniques. The demolition works will not significantly modify the layout and hydraulics of the existing drainage network, or substantially alter the quantity of storm flows entering it. Provided the environmental guidelines for the handling and disposal of discharges from construction sites, as stipulated in the Practice Note for Professional Persons, Construction Site Drainage (ProPECC PN 1/94) are followed, there should be no adverse impacts from demolition on drainage. Discharges to sewers or drains from the works must comply with the TM standards of the Water Pollution Control Ordinance (WPCO). Discharges to coastal waters should be avoided if at all possible. With the appropriate mitigation measures (ProPECC PN 1/94) in place there should be no significant impacts to drainage from the works. Therefore, it is not expected that the Water Quality Objectives will be exceeded during the demolition works.

11.8 Waste Management.

11.8.1 Wastes should be handled and stored using methods to minimise the potential for pollution and authorised reputable waste collectors used. Waste disposal permits shall be obtained from the appropriate authorities and collection of general refuse and general site housekeeping should be carried out in accordance with the Waste Disposal Ordinance (Cap 354), Waste Disposal (Chemical Waste) (General) Regulation (Cap 354) and the Government Land (Miscellaneous Provisions) Ordinance (Cap 28). Disposal shall be at licensed sites and records shall be maintained of the quantities of wastes generated, recycled and disposed. Provided that the recommendations put forward in this EIA report are conscientiously acted upon, the storage, handling, collection, transport, and disposal of wastes arising from the demolition of KCIP will be in full compliance with the regulatory requirements.

11.9 Environmental Monitoring and Audit.

11.9.1 The Proponent will appoint an environmental professional acceptable to EPD to design, implement and supervise the clean up of the site. EM&A for dust and noise is recommended to ensure that the dust criteria will not be exceeded. Monitoring of the removal of any contaminated materials identified in the Site Investigation is also recommended including a landfill gas monitoring programme during the land decontamination phase after the demolition of the main buildings and structures. Waste stream auditing should also be undertaken versus the Contractor’s proposed waste management plan.

11.10 Summary of Environmental Outcome

Summary of Environmental Outcome

11.9.1 The Environmental Outcome Profile has been included in Appendix F to provide basic project information on the main mitigation measures.

Appendix A

Preferred Demolition Methodology

Appendix A

Preferred Demolition Methodology

(Extracted From WP1

Originally Presented November 1999)

List of Abbreviations

AAP	Asbestos Abatement Plan
ACE	Advisory Committee on Environment
ACM	Asbestos Containing Material
AIR	Asbestos Investigation Report
AP	Authorised Person
APCO	Air Pollution Control Ordinance
BOO	Building Ordinance Office
CAP	Contamination Assessment Plan
CAR	Contamination Assessment Report
CED	Civil Engineering Department
CPLD	Committee on Planning & Land Development
DCDB	Draft Code of Practice on Demolition of Buildings
DSD	Drainage Services Department
EIA	Environmental Impact Assessment
EIAO	Environmental Impact Assessment Ordinance
EM&A	Environmental Monitoring & Audit
EMSD	Electrical & Mechanical Services Department
EPD	Environmental Protection Department
G I/C	Government, Institutional/Community
GDBL	Gin Drinker’s Bay Landfill
KCIP	Kwai Chung Incineration Plant
KCPTW	Kwai Chung Preliminary Treatment Works
LEHAGN	Landfill Gas Hazard Assessment Guidance Note
NWFB	New World First Bus Depot
PCWA	Public Cargo Working Area
PFBP	Public Fill Barging Point
PQA	Preliminary Quanlitative Assessment
PTW	Preliminary Treatment Works
RAC	Registered Asbestos Consultant
RSE	Resident Site Engineer
SR	Sensitive Receiver
TIA	Traffic Impact Assessment
TM	Technical Memorandum

SUMMARY

I. The Study Brief requires that the alternative methods of demolition of the Kwai Chung Incineration Plant and the Kennedy Town Comprehensive Development Area (the Project) to be investigated as a basis for defining the activities to be addressed within the environmental assessment. This Working Paper sets out the analysis of the alternative demolition options for both facilities and the major conclusions regarding demolition methods. The Working Paper also presents the major constraints associated with the Project.

II. The PPFS for Kwai Chung Incineration Plant concluded that it was not feasible to demolish the chimney by implosion (blasting) due to the short distances between the chimney and the surrounding structures and other local facilities, the high risk and the lack of cost effectiveness. Preliminary investigations for this Study have confirmed the severe concerns raised by various Government departments at the PPFS stage and confirmed the conclusion that blasting techniques should not be used for the felling of the chimney or the main building structures.

III. In addition to the original concerns it is now confirmed that parts of the chimney and the cladding of the buildings include asbestos containing materials (ACM). The presence of these materials alone is sufficient grounds to require that a non-blasting approach is adopted as all ACM must be removed in line with statutory requirements. A conceptual demolition method has been developed which avoids the any form of blasting to fell the chimneys or the associated buildings. Details of the engineering requirements for such an approach are presented in this report.

IV. The details of the constraints to demolition are presented in the main report. A conceptual demolition method has been developed which avoids most of the complications associated with blasting and provides flexibility for the implementation stages of the works.

V. The conclusion of this Working Paper is that non-explosive demolition methods should be used for the demolition of the Kwai Chung Incineration Plant.

A1. Introduction

A1.1 Background

A1.1.1 The Civil Engineering Department (CED) has appointed Atkins China Ltd. (ACL) to undertake the Environmental Impact Assessment (EIA) for the Demolition of the Kwai Chung Incineration Plant and the Kennedy Town Comprehensive Development Area (Agreement No. CE 15/99). The Kwai Chung Incineration Plant (KCIP) ceased to operate in May 1997 and has been decommissioned and the facilities require demolition. The main plant items have already been removed. The demolition of the remaining facilities on the site constitutes the Project as defined under the requirements of the Environmental Impact Assessment Ordinance (EIAO).

A1.1.2 The primary aim of this paper is to establish a conceptual demolition method and to define the major constraints, which must be considered in the final demolition process. The paper presents information to facilitate decisions on acceptable conceptual demolition methods for the Project as a basis for the remainder of the Study.

A1.1.3 To satisfy the requirements of the EIA it is necessary to define clearly the nature of the works involved in the demolition process. The development of a conceptual scheme for the demolition process in turn requires detailed analysis of the facilities and those surrounding uses and activities which might influence decisions on demolition. This paper presents this analysis. The conceptual scheme for demolition of the facilities has been developed based on practical experience and current demolition practice in Hong Kong as well as internationally.

A1.1.4 A description of the elements of the community and environment, likely to be affected by the proposed demolition activities is provided to ensure that any potential constraints on demolition works due to the need to protect sensitive receivers, surrounding infrastructure or facilities are considered. Such requirements may constrain the way the proposed Project is executed and affect the methods that can be used so as to influence the choice of demolition methods.

A1.2 Structure of the Report

A1.2.1 In addition to this introduction Working Paper 1 Report includes sections covering the following:

· Section 2 Project and Study Area

· Section 3 Appreciation and Understanding of Constraints to Demolition.

· Section 4 General Approach to Demolition of Buildings and Structures.

· Section 5 Conceptual Demolition Method for Chimney at KCIP.

· Section 6 Conclusions.

A2 proJecT and STUDY AREA

A2.1 Kwai Chung Incineration Plant (KCIP) Study Area

A2.1.1 The Kwai Chung Incineration Plant (KCIP) is located at Kwai Yue Road, Kwai Chung, facing the Rambler Channel and Tsing Yi South Bridge, with a site area of about 14,000 m² (Figure 2.1). The site is close to the Kwai Chung Park, the former Gin Drinkers Bay Landfill, and therefore may be impacted by contaminants and landfill gas generated from the landfill site.

A2.1.2 The KCIP site is adjacent to the Kwai Chung Preliminary Treatment Works (KCPTW) and part of the KCIP site overlaps the “Sewerage Tunnel Protection Area” of the Strategic Sewerage Disposal Scheme (SSDS), administered by Drainage Services Department (DSD).

A2.1.3 The KCIP site is currently zoned as “G/IC”, with no identified long term use of the area after demolition. However, the future land use is unlikely to be residential given the close proximity of the site to Gin Drinkers Bay Landfill and the Rambler Channel Bridge.

A2.1.4 A Public Fill Barging Point (PFBP), located on reclaimed land (Area 30D) to the north of the KCIP, is planned to be operational in early 2002. Construction of the PFBP is scheduled to commence in early 2001 for completion by the end of 2001. The PFBP is also subject to EIA under a separate study.

A2.1.5 The site is opposite the Rambler Channel Typhoon Shelter and Public Cargo Working Area. These facilities accommodate a range of cargo related activities including permanently moored barges. The structures which remain to be demolished are summarised in Table 2.1.

Table A 2.1 Structures to be demolished at KCIP

Building	Brief Description
KCIP Chimney	Reinforced concrete construction of diameter 6m – 12m and 150m high. Internal metal flues and platforms
KCIP Buildings	Single storey with steel frame, precast concrete slab, reinforced concrete partition, corrugated steel sheet external wall and roof. The overall size is approximately 83m x 92m on plan.
Weigh Bridge Office No2	Approximately 4m x 13m on plan.
Site Office/ Storage Buildings	2 storey height prefabricated building overall size is approximately 40m x 7.5m on plan.

A3 Appreciation and Understanding of Constraints to Demolition

A3.1 Background

A3.1.1 This section identifies the sensitive receives (SRs) affected by the Project as defined in the EIAO and discusses the implications of these and other nearby sensitive engineering projects and infrastructure with respect to the constraints they will place on demolition methods. Where relevant we have also noted the implications such sensitive locations may have on the potential for explosive demolition. Sensitive receivers and other constraints are shown in Figures 2.1 for KCIP.

A3.1.2 It has been assumed that the demolition for KTCDA will take place as soon as possible in order to allow future developments on and near the site. The earliest start date will be in 2001 with demolition works lasting about one year. There is currently no planned programme for the demolition of KCIP although a 16 month demolition phase was assumed in the PPFS.

A3.2 Sensitive Receivers at KCIP

Residential

A3.2.1 There are few SRs such as residential premises which are so close to the works at KCIP as to be severely affected by either explosive or conventional top down demolition. However residential receivers within 700m will be included in the EIA. This includes Cheung Ching Estate, Greenfield Garden and Grand Horizon (respectively more than 600m and 700m away across the Rambler Channel).

A3.3 Other Sensitivities near KCIP

A3.3.1 There are several engineering and other locations, which would be very sensitive to controlled demolition by implosion. These include:

· The Rambler Channel marine traffic and ferry services.

· Rambler Channel Typhoon Shelter and PCWA.

· The Public Fill Barging Point (PFBP) at Area 300.

· Container Terminal 5 (Kwai Tai Road).

· The seawalls and drainage channels other infrastructure around the area.

· The 200m Sewerage Tunnel Protection Area.

· The Kwai Ching Preliminary Treatment Works.

· The Kwai Chung Park (Gin Drinkers Bay Landfill).

· The Rambler Channel Bridge.

· The Tsing Yi Bridge.

· Kwai Tai Road and heavy vehicle access.

A3.4 Implications of Demolition by Implosion at KCIP

A3.4.1 The PPFS concluded that due to the short distances between the chimney and the surrounding structures, the high risk and lack of cost effectiveness meant that demolition of the single chimney by implosion was not feasible.

A3.4.2 The chimney at KCIP is 150m high. The exclusion zone under the “Draft Code of Practice for Demolition of Buildings (Buildings Department) would therefore require evacuation of an area up to 375m from the chimney during blasting. In the event that a Risk Assessment Report were conducted for this site, the result could require such a zone to be greater in order to minimise risks from ejecta. The possible limits of exclusion with respect to the chimney at KCIP are shown on Figure 2.1.

A3.4.3 The distance of residential SRs at Cheung Ching Estate, Greenfield Garden and Grand Horizon is 600m or greater. Whereas the results of a Risk Assessment cannot be predicted, experience suggests that such distances would be likely to place these SRs well beyond any likely exclusion zone. Therefore it is unlikely that these SRs would need to be evacuated.

A3.4.4 The distance to industrial buildings over the Rambler Channel would fall within a three chimney height radius and these buildings may require evacuation in then event that demolition by implosion was chosen

A3.4.5 Engineering and other locations are much nearer and would be very sensitive to controlled explosive demolition. The proximity of some facilities places them at physical risk of damage from vibration or flying debris. Others would be impacted by the need to suspend services and the costs of co-ordinating the closure of many services in the area could be unacceptable. Either individually or together the impact on these facilities/works could be sufficient to dictate against the use of demolition by blasting.

A3.4.6 A large section of the Rambler Channel, the Rambler Channel Typhoon Shelter, the PCWA and part of Container Terminal 5 would be likely to fall within an exclusion zone for explosive demolition. The suspension of services and marine traffic in the Rambler Channel, necessary for an demolition by blasting, presents a major potential impact. Marine Department have indicated that prima facie the closing the Rambler Channel to marine traffic is unacceptable and that they have an in principle objection to this line of action. The implications of demolition by blasting for evacuation of Rambler Channel, Typhoon Shelter and suspension of activities in the PCWA and Container Terminal 5 are therefore considered to be unacceptable.

A3.4.7 The Public Fill Barging Point (PFBP) at Area 30D is scheduled to be under construction some time in 2001 which is before the target date for the completion of the demolition indicated in the PPFS. If the chimney were to be felled using a blasting technique, the target area for the fall could just fit within the KCIP site towards the east. Otherwise the target area would be Area 30D. In the latter case there is a potential conflict for demolition by explosive methods which would be impossible prior to the subsequent cessation of activities at Area 30D as and when the barging point closes.

A3.4.8 The Kwai Chung Preliminary Treatment Works (KCPTW) is located immediately adjacent to the KCIP and the base of the chimney is only about 20m from the main KCPTW control building. The control centre is manned during the daytime and runs with automatic control from late afternoon, overnight, until early morning. The Drainage Services Department has indicated that the control equipment is very sensitive to vibration and they are especially concerned that vibration caused by blasting of the chimney could damage the equipment and possibly even the building fabric. Regardless of the method of demolition, vibration control techniques for the site may be required because of the proximity of the Kwai Chung PTW.

A3.4.9 The demolition works and the chimney are within 100m of the vertical shaft tunnel of the SSDS and require special scrutiny by Government. Part of the site is within the 200m outer limit of the Sewerage Tunnel Protection Area. The Technical Notes for Guidance in Assessing Effects of Civil Engineering Works/Building Development on Sewage Tunnel Works (PNAP 165) require that peak particle velocities (PPV) at any sewerage tunnel structure resulting from blasting or other operations which can induce prolonged vibration, shall not exceed 25mm/sec. The maximum peak particle velocities for other operations shall not exceed 15mm/sec. Drainage Services Department have also expressed concerns that such maximum PPV could be exceeded at the sewage tunnels with blasting techniques. Given the sensitivity of the SSDS project, the use of implosion techniques is considered to be unacceptable.

A3.4.10 The approach viaduct of the Rambler Channel Bridge is within 40m of the chimney. Highways Department have expressed concerns that blasting techniques could cause vibration or release ejecta which could damage the structure. The Bridge would also have to be closed temporarily, which is unacceptable for this main route to the Airport.

A3.4.11 There are potential landfill gas hazards associated with the Kwai Chung Park (Gin Drinkers Bay Landfill). The landfill gas hazard assessment, undertaken to identify the nature and extent of landfill gas release, is included in the EIA Report. At this stage explosure demolition would appear to be a very high risk option. Site safety measures implemented in the site investigation stage will need to be implemented in the demolition phase, in accordance with established standards and guidelines and the findings of the hazard assessment.

A3.4.12 The local road network is currently busy with much heavy traffic serving not only the PCWA but also other industrial facilities nearby. Transport Department expressed general concerns about the potential impact of the need to close roads to allow blasting techniques. Generally road closures would be unacceptable unless proved acceptable. A TIA would be required to assess impacts on all roads in the exclusion zone and the public transport system and a feasible traffic diversion scheme would need to be developed. Emergency plans would also need to be developed. Given the plethora of other non-traffic constraints, these measures have not been detailed at this stage.

A3.5 Implications of the Presence of Asbestos Containing Materials

A3.5.1 Asbestos Investigation Reports and Asbestos Abatement Plans for both sites are required under the Air Pollution Control Ordinance (APCO) prior to the commencement of any asbestos abatement work. Reports and plans prepared by Registered Asbestos Consultants (EPD register RACs 1014 and 1019) indicate asbestos containing materials (ACM) are present at the Site.

A3.5.2 The Brief assumes that any asbestos containing materials (ACM) present in the chimneys and superstructures within the two sites will be removed before commencement of the demolition works. However, experience suggests that in practice the asbestos abatement processes will run more smoothly if both asbestos contractors and civil demolition contractors work in tandem, as has been the case with the civil demolition of the remaining buildings and structures at other large industrial locations in Hong Kong. This is generally due to the convenience of the main civil demolition contractors providing access (scaffolding etc.) to the ACM, for the asbestos contractor. In other cases it may be necessary for the civil demolition contractor to remove large sections of materials for the asbestos contractor to gain access to the ACM. Further details are presented in the dedicated Asbestos Study Report.

A3.5.3 Bulk asbestos removal of ACM from the incineration plant was undertaken by Government, prior to the removal of plant and machinery. Inspection of the plans and recent site surveys show that low risk asbestos containing materials are present in the chimney of the KCIP. The cladding to the superstructures of the KCIP incinerator building is also similar to other typical corrugated metal weather cladding with asbestos paint (ACM).

A3.5.4 There is also low risk asbestos containing material (ACM) present in the ventilation louvres to the chimney. The louvres are also made from metal with an asbestos type mastic protective paint coating. This is identical to ACM typically found on louvres at other industrial sites in Hong Kong.

A3.5.5 Drawings indicate that an asbestos cement plate was used as a thermal insulation to the chimneys internal flue guide sections. Physical inspection of this material shows it to be a low risk ACM in good condition. However the location means that a controlled removal may only be possible as the chimney is progressively dismantled and as the chimney and flue sections are removed. Therefore blasting will not be an option.

A3.5.6 Other areas have been investigated but no potential ACM has been identified. Details are presented in the dedicated Asbestos Study Report (Asbestos Investigation Report and Asbestos Abatement Plan).

A3.6 Conclusion

A3.6.1 Based on the information presented in Section 3 the consultants believe that sufficient information has been gathered to recommend that the preferred method of demolition should adopt a top-down, non-explosive, non-blasting approach for the demolition of the Kwai Chung Incineration Plant.

A4 General Approach to Demolition of Buildings and Structures at KCIP

A4.1 General Approach

A4.1.1 This section seeks to illustrate some of the more general procedures for demolition that apply at KCIP. The intention in this and sections 5 is not to prescribe a precise method or provide a work specification or a demolition plan but to indicate the approach which should be taken, in sufficient detail to facilitate broad agreement on the methodology and progress EIA.

A4.1.2 Whereas the eventual detailed demolition plan of the selected demolition contractor(s) may not necessarily adopt the methodology proposed in this working paper, the consultants believe that general characteristics of the methods are appropriate. The methods are sufficiently effective and applicable for the tasks and where possible methods that will help reduce noise and dust nuisances have been chosen. The options selected are also broadly in line with the Draft Code of Practice for Demolition of Buildings (DCDB, Buildings Department 1998) which will also need to be observed at the detailed design stage.

A4.1.3 The overriding concerns for the demolition Project will be safety and minimisation of environmental impacts. This will include the safety of the operatives, safety of the other workers on the site and safety of the general public as well as protection of adjacent facilities and minimisation of nuisances.

A4.1.4 The Contractor should during the course of demolition, ensure and verify that all utilities and services have been rendered safe.

A4.2 Hoarding and Site Access

A4.2.1 Typical hoardings would to be provided along the site boundaries. Portable barricades will be used to cordon off different work zones where demolition is in progress. Where conditions warrant the Contractor should seek opinion and advice from the Site Engineer/AP/RSE in order to modify such plans accordingly.

A4.2.2 The buildings and chimneys are totally within the proposed Project sites and access would be controlled by security guards. No members of the public or unauthorised person would be allowed to enter the sites.

A4.2.3 Only contractors’ personnel and Government officials concerned with the demolition would be allowed within the contractors working area.

A4.3 Demolition Principles

A4.3.1 Building and other structures should generally be demolished in the reverse order to that of their construction. The order of demolition for building would be progressive, storey by storey, having regard to the type of construction.

A4.3.2 As a general rule, wherever possible, external non-loading bearing cladding or any non-structural work should be removed first. All asbestos containing materials (ACM, particularly any ACM panels, would be removed prior to commencement of demolition works where ever possible. Other ACM may need to be removed as access is gained to particular areas and as the demolition progresses (see also section 3).

A4.3.3 Overloading of any parts of the remaining structure with debris or other materials should be avoided. Where materials and debris and are lowered from higher levels, care should be taken to prevent the material from swinging in such a manner that it creates a danger to the workers on site or the surrounding structures. Larger pieces of debris should be broken down into manageable sizes, subject to a maximum of 1.0m x 1.0m. The weight of loaded buckets for unloading debris would be limited to say, 200 kg.

A4.3.4 All debris would be removed at frequent intervals and stockpiles should not be allowed to build up excessively. In general it is anticipated that demolition waste would be removed on a daily basis with several tens of lorries leaving the site each day at the peak of demolition activities.

A4.3.5 Reinforced concrete structural members should be cut into lengths appropriate to the weight and size of member before being lowered to the ground. Where possible, crane and lifting gear should be used to support beams and columns whilst they are being cut and lowered to the ground.

A4.3.6 Removal of bricks walls should be from top to bottom in horizontal runs of not more that 300mm wide.

A4.3.7 Before and during demolition, the Contractor should pay attention to the nature and condition of the concrete, the condition and position of reinforcement, and the possibility of lack of continuity of reinforcement should be ascertained. Attention should also be paid to the principles of the structural design to identify parts of the structure, which cannot be removed in isolation. If uncertainties exist then advice of the Site Engineer/AP/RSE’s advice should be sought.

A4.3.8 During demolition works, if anomalies or irregularities are discovered in structural elements, regarding reinforcement bar details, alteration and addition works, unauthorized building works, etc, demolition works should stop immediately. AP/RSE should be informed and works will commence only after AP/RSE approval is obtained.

A4.3.9 If the Contractor discovers that the removal of certain parts of the buildings or structure during demolition would result in other parts becoming unsafe, it would be necessary to determine where temporary support will be needed and the advice of the Site Engineer/AP/RSE should be sought.

A4.4 General Safety Measures

A4.4.1 The Contractor will need to carry out works in accordance with the Factories and Industrial Undertakings Ordinance, particularly the Construction Site (Safety) Regulations and the Code of Practice for Scaffold Safety, as well as all other statutory requirements and guidelines covering health and safety issues.

A4.4.2 All contractor and sub-contractors should be competent and qualified in demolition works. Site Engineer/AP/RSE(s) will need to ensure that all levels of Contractor(s) and his subordinates are fully conversant with the demolition plans, method statements and procedures.

A4.4.3 Where scaffolding is used, the Contractor should arrange for a competent scaffolder to visit site and inspect the scaffolding work, and to make any adjustments required to the scaffolding as the work proceeds, to ensure its stability.

A4.4.4 The Contractor shall also appoint a competent person, experienced or trained in the type of operation being performed at that particular time, to supervise and control the work on site.

A4.4.5 The Contractor should ensure that every work place, approach and opening, which may pose a danger to persons employed and others should be properly illuminated and protected.

A4.4.6 The use of all mobile cranes must be strictly controlled to ensure that cranes of adequate capacity will be used for lifting under different loading conditions.

A5 Principles of Chimney Demolition at KCIP

A5.1 Access

A5.1.1 The main site would be protected by security personnel and a high hoarding such that the public would be totally excluded from the Project.

A5.1.2 The area beneath the chimneys would be cordoned off and only authorized staff involved in the demolition of the chimneys would be allowed admission into the vicinity of the chimney structures.

A5.2 General Approach

A5.2.1 The principle of the demolition procedure for the upper portion of the chimneys (10m from ground level or greater) is that the chimneys will be cut into small pieces by hand held tools on the spot by operatives who would work from working platforms inside the chimney. Hydraulic breakers would be used for the remaining lower portions of the chimneys.

A5.2.2 The concrete liner and the metal flues will be removed manually. The principle of the demolition procedure is that the chimney and flues would be cut up into pieces and these pieces lowered to the ground by derrick. This method would ensure that full control of the debris and that the pieces of reinforced concrete are not left to free fall (Figure 5.1).

A5.3 Preparation

A5.3.1 The area surrounding the chimney would be made secure and all necessary barricades erected. Only Authorized personnel would be allowed into the area.

A5.3.2 Two crane shafts each size 1.5m x 1.5m would be erected inside the chimney up to 100m high. The two crane shafts would be reduced to 1m x 1m above 100m high.

A5.3.3 A derrick would be mounted on the top of each crane shaft for hoisting & lowering of tools and debris.

A5.3.4 A working platform would be constructed at a level 2m below the top of the chimney.

A5.3.5 Panel of mesh flooring of the existing steel platform at each level would be removed to facilitate creation of the crane shaft and the lowering of debris.

A5.4 Sequence of Operations

A5.4.1 Using hand held tools, the insulation of the flue (non-ACM) would be removed down to 2m below top level.

A5.4.2 On the platform the concrete liner and metal flues are removed by hand and loaded into skips for lowering down to adjacent ground.

A5.4.3 The metal flues would be flame cut into 2m maximum length for lowering down to ground level.

A5.4.4 Using light weight chain saws, the chimney would be cut up into pieces of maximum size 1m x 1m, each piece being secured by a cable to a derrick to ensure that when the cutting is completed the concrete is fully supported.

A5.4.5 The individual pieces can then be lowered to the ground in a safe and controlled manner, thus ensuring there will be no free falling of material.

A5.4.6 The crane shafts and derricks can then be lowered by 2m. A new platform will be erected 2m below the new top level of the remaining chimney portion. The platform size would be progressively enlarged, as demolition progresses downward to accommodate the increasing diameter of the Chimney.

A5.4.7 This process would be repeated until only the lower 10m of the chimney remained. These remaining lower levels would be within the reach of normal, mobile hydraulic breakers. Such breakers would be on the ground and the lower portion of the chimney would be removed by these means.

A5.5 Duration of Demolition

A5.5.1 The buildings and chimney at KCIP can be demolished and removed by the conventional top down demolition using hand held tools and mechanical breaking methods. In order to avoid hazards caused to the adjacent areas, all the structures and other buildings near to the chimneys would be demolished and removed prior to the demolition of the chimneys. The estimated time for the completion of these works included in the PPFS was 16months which would appear to be ample time for demolition base on the above methodology.

A.6 Conclusion

A6.1.1 This working paper has presented information concerning the difficulties associated with the demolition of the Kwai Chung Incineration Plant and the demolition of Kennedy Town Comprehensive Development Area (the Project). In order to facilitate the progress of the Initial Assessment Report and the EIA process as a whole it is necessary to define the Project in sufficient detail in line with the objectives of the Study.

A6.1.2 The primary aim of this working paper is to establish a conceptual demolition method for both Project in order to facilitate progress the EIAs. During the preliminary investigations the consultants have taken note of the work conducted previously and also initiated discussions with relevant Government departments, many of whom have expressed severe concerns with the proposals to include any form of blasting techniques for the felling of the chimneys or the main building structures at either site.

A6.1.3 In the selection of an appropriate demolition method the physical effects on local sensitive receivers and adjacent structures are very important. There are also hidden costs arising from the need to carefully co-ordinate a demolition by implosion. The effect on marine and road transport systems and the complexity of implementing controls is also an important factor. The cumulative impacts of the surrounding interfaces on the project methods have been assessed and make demolition by implosion at either site a potentially costly and a very high risk proposal.

A6.1.4 In order to facilitate the progress of the Initial Assessment Report the consultants therefore seek endorsement of the content of this working paper. Whereas the eventual detailed demolition plan of the selected demolition contractor(s) may not necessarily adopt the precise methodology proposed in this working paper, the methods used should adopt top-down, non-explosive methods for the demolition of the Kwai Chung Incineration Plant and the demolition of Kennedy Town Comprehensive Development Area.

Appendix B

Selected Gin Drinkers Bay Landfill Gas

Monitoring Data

(Source: ITS Intertek Testing Services, Landfill Gas Analysis for Further Environmental Monitoring at North West New Territories Landfills and Gin Drinkers Bay Landfill.)

Appendix B Selected Gin Drinkers Bay Landfill Gas Monitoring Data

	GDBGW4				GDBGW5				GDB2				GDB1
Date	CH4	LEL%	CO2	O2	CH4	LEL%	CO2	O2	CH4	LEL%	CO2	O2	CH4	LEL%	CO2	O2
Jan 99	60.5	>100	18.2	0.80	0.00	0	0.30	19.0	0.00	0	1.55	18.4	21.8	>100	17.0	1.20
Dec 98	62.3	>100	19.0	2.80	0.00	0	0.01	20.7	0.00	0	0.80	20.0	42.6	>100	19.8	1.10
Nov 98	55.1	>100	13.9	3.30	0.00	0	0.00	20.2	0.00	0	0.76	19.6	37.2	>100	21.0	1.20
Oct 98	51.9	>100	20.2	7.60	0.00	0	0.00	20.8	0.00	0	0.37	20.2	36.1	>100	19.7	0.00
Sep 98	44.2	>100	17.8	3.10	0.00	0	0.00	20.6	0.00	0	0.29	18.5	43.4	>100	24.2	0.00
Aug 98	63.8	>100	30.4	2.80	0.00	0	0.00	20.9	0.00	0	1.82	18.7	66.0	>100	24.5	0.50
Jul 98	73.0	>100	34.0	1.30	0.00	0	0.00	20.9	0.00	0	0.00	20.0	67.1	>100	28.8	0.50
Jun 98	52.8	>100	30.5	3.90	0.00	0	0.00	20.9	0.00	0	3.83	16.6	62.1	>100	23.7	0.40
May 98	60.4	>100	28.5	3.40	0.00	0	0.00	20.7	0.00	0	3.56	16.1	40.0	>100	21.8	0.50
Apr 98	43.0	>100	21.4	6.80	0.00	0	0.00	19.8	0.00	0	1.78	18.0	35.3	>100	26.1	0.10
Mar 98	69.8	>100	25.0	1.20	0.00	0	0.00	19.8	0.00	0	2.85	15.9	50.1	>100	25.3	0.30
Feb 98	54.4	>100	21.8	3.70	0.00	0	0.60	18.4	0.00	0	2.45	15.5	40.3	>100	24.9	0.70
Jan 98	61.7	>100	27.3	0.30	0.00	0	0.00	19.7	0.00	0	4.47	17.4	22.5	>100	20.6	1.40
Dec 97	59.4	>100	20.6	0.70	0.00	0	0.00	19.8	0.00	0	0.34	18.5	16.0	>100	17.4	4.40
Nov 97	51.7	>100	21.8	4.70	0.00	0	0.00	19.8	0.00	0	1.90	17.0	27.6	>100	19.8	5.70
Oct 97	42.0	>100	13.1	6.60	0.00	0	0.00	19.8	0.00	0	1.12	18.4	55.2	>100	25.7	0.50

Appendix C

Water Quality Standards

(Source: Standards for Effluents Discharged into Drainage and Sewerage Systems Inland and Coastal Waters, EPD)Objectives

Appendix D

Site Safety Precautions

1. Hazards and Safety Precautions

1.1 Introduction

1.1.1 Hazards which may arise at KCIP generally be classified under the following headings:

· General Hazards

· Gas hazards

· Landfill leachate

1.2 General Safety

Operators

1.2.1 Operators should be experienced and licensed drivers. Where possible, all operators should be required to demonstrate their driving ability in the equipment they will be operating and under actual job conditions before recruitment.

1.2.2 Only personnel with valid driving licences are permitted to drive any site cars or vehicles. In the case of vehicles which are not intended for road use, the driver should hold a licence for the nearest comparable class of road vehicle.

1.2.3 For operators employed, a photocopy of their driving licence should be obtained. Their validity and the class of vehicle licences to drive should be checked.

1.2.4 The site office should keep an up to date list of names and copies of driving licences of drivers of motor vehicles and plant.

Equipment

1.2.5 Drivers should make a daily inspection of their vehicles. The check should include steering, brakes, mirrors, lights, horn, tires and windshield wipers. Reverse alarms which must be installed on all trucks and lorries should also be checked to ensure safe operation. Drivers are required to report all defects to the plant mechanic foreman, and repairs should be made promptly.

Roads

1.2.6 Site roads should be maintained in safe operating condition at all times. Roads should be built to provide adequate drainage and width and should avoid sharp curves, abrupt changes in gradient and excessive gradients. The use of one-way traffic roads is recommended wherever possible. Site roads must have clearly visible signs in both Chinese and English.

Transporting Personnel

1.2.7 Personnel should only ride in vehicles designed for the purposes. It is forbidden for personnel to take rides with operations where no specific sear has been provided for passengers.

Loading Lorries

1.2.8 Materials loaded onto lorries should be within the permitted safe weight limit and should not project beyond the lorry body or be placed in an unsafe pile in such a manner as to present a hazard to other vehicles, pedestrians or structures.

General Requirements

1.2.9 Drivers leaving the driver leaves the driving seat of a vehicle shall ensure the engine shall is switched off, the gear engaged and parking brakes applied. The wheels shall be chocked on slopes.

1.2.10 Lorries should only be backed under the direction of a marshal or spotter. In dumping areas, the marshal and spotters should be identified by a reflective vests.

1.2.11 All operators and drivers are required to observe speed limits at all times.

1.2.12 All pedestrians requiring to pass close to an operating machine shall ensure that the machine operator has been them and has stopped operation prior to proceeding.

1.2.13 All personnel working on site roads or directing traffic shall wear reflective vests.

Plant Noise

1.2.14 The foreman shall ensure that noise assessments are carried out on all noisy plant used on site. Any plant that creates noise exceeding the first action level stated in the Factories and Industrial Undertakings (Noise at Work) Regulations should be identified, with notices fixed to the plant and appropriate action should be taken as described in the Regulations to avoid exposure to the noise. Attention shall also be paid to the recommended Environmental Monitoring and Audit plan for the site.

1.3 Gas Hazards

1.3.1 Waste in the landfill emits a mixture of gases. The composition of gases at KCIP is not known however leachate gases of the following composition would not be untypical for such a site approximately as follow:

· 45-55% methane – Explosive.

· 44-54% Carbon Dioxide – Asphyxiant.

· 1% Other gases – mainly organic vapours.

1.3.2 The main danger from landfill gas is due to explosion of methane, however, if large concentrations of gas displace air there can be a danger of asphyxiation or poisoning. Gas concentrations are likely to be higher near the tops of gas wells and near exposed areas of leachate collection stone.

1.3.3 All personnel are advised to observe the following guidelines to avoid gas accidents:

· No smoking on the site.

· Do not enter trial pits unless the air quality has been tested (see 1.6)

· If any personnel has any of the following health symptoms while working at, in or near a trial pit on the Site he should move away from the area of the trial pit immediately:

- Headache,

- Dizziness / lightheadedness,

- Tingling or numbness,

- Nausea,

- Blue lips or bright red skin.

1.3.4 Once the affected person has moved to a position remote from the trail pit he should inform his supervisor who will evaluate the situation, decide whether other persons should be evacuated from the immediate area whether medical aid is required.

1.4 Landfill Leachate

1.4.1 Solid waste in the reclamation under the site or leachate originating from GDBL may be toxic, the following rules should therefore be observed:

· If leachate has to be handled, or groundwater samples lotion ensure that the operatives wear protective clothing and gloves. If any operatives come into contact with leachate, should be immediately wash the affected area with clean fresh water.

· Ensure that any broken skin, cuts, graze and the like do not come into contact with waste or leachate. All cuts etc should be covered prior to working on the site.

· Safety boots should be worn on the site.

· All operatives should keep a lookout for sharp objects on the site such as broken glass, syringe needles, nails in pieces of wood and the such like.

· If any operative receives any cuts or grazes whilst he is on he landfill, he should report this immediately to his supervisor who will arrange for medical attention.

1.5 Site Safety Precautions

1.5.1 All operational and supervisory staff’s attention shall be drawn to the hazards of landfill gas generated by decaying refuse in the landfill which may have migrated to the KCIP Site. This gas can endanger the safety of workers, as the flammable gas it contains explosive potential once it is mixed with air. Attention shall also be given to other components of the gas which have the potential to cause asphyxiation or toxic effects under appropriate conditions.

1.5.2 Smoking and the use of naked lights and welding shall be prohibited in areas of the site where landfill gas likely to be present and can migrate. Warning signs designating “no smoking areas” shall be put up to remind workers of these restrictions.

1.5.3 Plant and mobile plant shall carry fire extinguishers, and shall be equipped with properly functioning spark arrestors and automatic air intake shut down valves. Wherever possible diesel operated plant shall be used.

1.5.4 No fires shall be permitted on the site. Operational and supervisory staff shall immediately extinguish any fires within the site.

1.5.5 Confined spaces and excavation where entry is required shall be treated as described under Section 1.6.

1.5.6 Temporary offices, huts and storage containers shall not be located where infiltration of gas could occur, and in any event shall be provided with simple gas protection measures and detection systems where appropriate.

1.5.7 Fire fighting facilities shall be maintained on the site, and shall be property housed and kept readily available for instant use.

1.5.8 The site designated emergency co-ordinator shall liaise with the Fire Services Department to ensure that they are in a position to respond quickly to any fire or explosion which may occur. The emergency co-ordinator shall notify the Fire Services Department immediately in the event of any such emergency.

1.5.9 The site agent shall carry out the following:

· Prepare detailed working procedures and safety precautions for the work being carried out.

· Instruct the workmen and other staff in the working procedures and safety precautions to be followed.

· Record in writing that the workmen and other staff have been so instructed.

· Provided sufficient equipment so the working procedures and safety precautions can be followed.

· Ensure the working procedures and safety precautions are adhered to.

1.6 Working in Confined Spaces

1.6.1 The Site contractor shall ensure that any work in a confined space, as defined in the Factories and Industrial Undertakings (Confined Spaces) Regulations, complies with the requirements of the Regulations and is in accordance with the Guide to the Regulations published by the Labour Department.

1.6.2 All entries into confined spaces will be subject to a written detailed safe working procedure and a permit to work procedure. The written safe working procedure will include, but may not be limited to, details of the following: -

· arrangements for detecting toxic or explosive gas or oxygen deficiency, and the detection equipment to be used.

· supervision arrangements

· safety and emergency rescue equipment to be used, including breathing apparatus, safety harness and safety ropes

· permit to work procedures

1.6.3 All persons entering a confined space shall have received appropriate training from authorised bodies.

1.6.4 All written safe working procedures and completed “Permit-To-Work Certificate” shall be kept in the site office.

Appendix E

Criteria for Soil Contamination and Landfill Disposal

of Contaminated Soil

Landfill Disposal Criteria for Contaminated Land

Metals

Parameter	TCLP Limit (ppm)
Cadmium	10
Chromium	50
Copper	250
Nickel	250
Lead	50
Zinc	250
Mercury	1
Tin	250
Silver	50
Antimony	150
Arsenic	50
Beryllium	10
Thallium	50
Vanadium	250
Selenium	1
Barium	1000

Source : Guidance Notes for Investigation and Remediation of Contaminated Sites (EPD TR1 / 99).

Metals

Toxicity Characteristics Leaching Procedure (TCLP) test for materials contaminated with heavy metals needs to be carried out in accordance with the testing frequency and requirements as stipulated in EPD’s Guidance Notes for Investigation and Remediation of Contaminated Sites.

TPH and PAH

Toxicity Characteristics Leaching Procedure (TCLP) tests for TPH, PAH and BTEX contaminated materials have to be carried out according to the testing frequency and requirenments as stipulated in EPD’s “Guidance Notes for Investigation and Remediation of Contaminated Sites. Pretreatment is required to bring levels of TPH to below the TCLP limit of 2,500ppm PAH/BTEX to below the TCLP limit 1,000ppm.

Dioxins and Furans (PCDD/PCDF)

Toxicity Characteristics Leaching Procedure (TCLP) tests for PCDD/PCDF contaminated materials have to be carried out according to the testing frequency and requirenments as stipulated in EPD’s “Guidance Notes for Investigation and Remediation of Contaminated Sites. Pretreatment is required to bring levels of PCDD/PCDF to below the TCLP limit of 1ppb PCDD/PCDF (TEQ) with a testing frequency of one test per 100 tonnes of treated stabilised materials.

N.B.

TEQ =toxicity equivalent units.

ppm = mg/kg (miligrams / kilogram)

ppm = mg/g (micrograms / gram)

ppb = ng/g (nanograms / gram)

ppb = 1000pg/g (picograms / gram)

Appendix F

Environmental Outcome ProfileComments & Responses

Appendix G

Comments & Responses

Environmental Outcome Profile

The Project

Total Project Cost :~HK$134 million

Cost of Environmental Component (EIA, Study and Mitigation Measures) say HK$19.0 million.

Road works = N/A

Railway =N/A

Reclamation / dredging =N/A

Power station =N/A

Drainage work =N/A

Development Study = N/A

Others = Decommissioning of a municipal incinerator comprising:

a) Demolition of Main Plant Building, measuring 90m x70m x 45m high;

b) Demolition of chimney 150m high;

c) Demolition of administration/storage building 2-storey high, and other ancillary structures; and

d) Ground decontamination.

EIAO Application Reference:

An application Reference (No. ESB-024/1998) for an Environmental Impact Assessment (EIA) Study Brief under section 5(1)(a) of the Environmental Impact Assessment Ordinance.

Key Outcomes :

Population Protected :

During demolition of the incineration plant and soil remediation, dwellings within 700m of the project boundary would contain a population of approximately 36,000. In addition there would be workers accessing the work sites adjacent as well as occupants of the 90,000 or so vehicles using the adjacent highways on a daily basis.

The residents would be potentially affected by cumulative noise from the demolition. The EIA has demonstrated that, using the recommended demolition methodology the population would not be subject to exceedances of the relevant construction noise criteria under the EIAO TM.

During the demolition, the population of approximately 36,000 within 700m of the project boundary would potentially be affected by cumulative dust. Implementing effective and adequate dust suppression will include measures such as the damping down of all stockpiles and wheel washing facilities to ensure vehicles moving to and from the site and around the site would not create any significant increase to dust in the area. Therefore, the avoidance of nuisances can be ensured during the whole demolition period by the adoption of measures to ensure compliance with the Air Pollution Control (Construction Dust) Regulations.

Problems Avoided :

During the demolition phase the recommendation for use of non-blasting methods will avoid the need to evacuate several adjacent sites and avoid the need to temporarily close major road traffic arteries in the vicinity. Remediation of contaminated soil in-situ will avoid the need to use valuable landfill space and ensure that the site is suitable for all possible future use.

The use of dust mitigation measures will avoid nuisances for the adjacent work sites or vehicles on the highways. Water quality impacts will be avoided by the treatment of surplus site run-off, groundwater etc. Hazards to personnel will be avoided by the implementation of a landfill gas monitoring programme. The environmental monitoring and audit programme will ensure that accepted environmental standards are met.

Environmentally Friendly Designs :

During the demolition phase the recommendation for non-blasting methods will reduce noise, dust and vibration and the use of other environmentally friendly methodologies and waste disposal measures will minimise the impact on the receiving environment as follows:

· Mitigation measures and monitoring and audit programmes are recommended for the demolition and soil remediation phase for dust and waste management to ensure that waste disposal is in line with EIA recommendations to prevent adverse environmental impacts.

· Noise and air quality impacts at the sensitive receivers can be reduced to within accepted norms by the use of the methods recommended in the EIA.

· Environmental benefits from implementing this Project include the removal of an unsightly and derelict building, decontamination of the soil underneath the site and removal of several tonnes of asbestos waste.

Others: A Pre EIAO ESMG meeting was held in EPD’s office on 2 March 2001.