Civil Engineering Department

The Government of the Hong Kong

Special Administrative Region

 

 

 

 

Agreement No. CE 15/99

 Demolition of Buildings and Structures

in the Proposed Kennedy Town

Comprehensive Development Area Site

 

 

 

 

 

 

Environmental Impact Assessment (Final Report)

 

 

 

 

September 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 Incinerator Plant and Kennedy Town CDA

 

 

Project No. :  2996

 

 

Document No. :    2996-OR025-05

 

 

 

Controlled Copy No. :

 

           

 

Document Title :  Final Environmental Impact Assessment
                           Kennedy Town CDA

 

 

 

Covering Letter / Transmittal Ref. No. :

                           2996/15.40/

 

 

Date of Issue :

    September 2001

 

Revision, Review and Approval/Authorisation Records

05

6th Issue

Various/

JWS/

DG/

04

5th Issue

Various/

JWS/

DG/

03

4th Issue

Various/

JWS/

DG/

02

3rd Issue

Various/

JWS/

 

DG/

 

01

2nd Issue

Various/

WD/

DG/

00

1st 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

 

1-45

Civil Engineering Department

46-47

ACL – ELAN

 

 

 

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 KTCDA.. 2-1

2.2        Sensitive Receivers. 2-2

2.3        Options for Demolition. 2-4

2.4        General Approach to Demolition of Buildings and Structures at KTCDA.. 2-7

2.5        Principles of Chimney Demolition at KTCDA.. 2-8

3.      Asbestos Control 3-1

3.1        Site Location and Description. 3-1

3.2        Asbestos Investigation Methodology. 3-2

3.3        ACM to be Removed. 3-3

3.4        Justification of Methods. 3-6

3.5        General Safety Measures. 3-8

3.6        Programme for Asbestos Removal 3-8

3.7        Regulations, Codes of Practice and Local Requirements. 3-9

4.      Land Contamination. 4-1

4.1        Requirement for Land Contamination Assessment 4-1

4.2        Land Use History. 4-1

4.3        Site Inspection. 4-2

4.4        Methodology. 4-4

4.5        Sampling Locations and Analysis of Results. 4-6

4.6        Contamination Assessment 4-14

4.7        Remediation Action Plan. 4-17

4.8        Procedures for Management of Contaminated Rubble / Ash Waste  Material 4-23

4.9        Management of Contaminated Soil Material 4-26

4.10      Protection of Site Workers During Excavation and Treatment of Soils. 4-29

5.      Noise. 5-1

5.1        Introduction. 5-1

5.2        Government Legislation and Standards. 5-1

5.3        Existing Noise Conditions. 5-2

5.4        Noise Sensitive Receivers. 5-2

5.5        Potential Sources of Impact 5-3

5.6        Assessment Methodology. 5-3

5.7        Evaluation of Impacts. 5-5

5.8        Mitigation Measures. 5-6

6.      Air Quality. 6-1

6.1        Introduction. 6-1

6.2        Government Legislation and Standards. 6-1

6.3        Dust Suppression Measures. 6-2

6.4        Vehicle Emissions. 6-3

6.5        Odour. 6-3

6.6        Conclusions. 6-3

7.      Waste Management 7-1

7.1        Introduction. 7-1

7.2        Assessment Criteria and Methodology. 7-1

7.3        Waste Disposal Ordinance. 7-1

7.4        Waste Disposal (Chemical Waste) (General) Regulation. 7-2

7.5        Dumping at Sea Ordinance. 7-2

7.6        Land (Miscellaneous Provisions) Ordinance. 7-2

7.7        Public Cleansing and Prevention of Nuisance Regulation. 7-2

7.8        Additional Guidelines. 7-3

7.9        Impacts of Wastes Generated from Demolition. 7-4

7.10      Mitigation Measures. 7-7

7.11      Waste Management Planning. 7-11

8.      Environmental Monitoring and Audit 8-1

8.1        Introduction. 8-1

8.2        Environmental Monitoring and Audit 8-1

8.3        Event Contingency Plans (ECPs). 8-2

8.4        Reporting. 8-2

9.      Conclusions and Recommendations. 9-1

9.1        Introduction. 9-1

9.2        Demolition Methodology. 9-1

9.3        Asbestos. 9-1

9.4        Land Contamination and Remediation. 9-2

9.5        Noise. 9-2

9.6        Air Quality. 9-2

9.7        Waste Management. 9-2

9.8        Environmental Monitoring and Audit. 9-3

 


 

List of Tables

Table 2.1      Structures to be demolished at KTCDA   2-2

Table 3.1      Main Locations for ACM Investigation at KTCDA   3-3

Table 3.2      Areas of ACM Identified by Functional Zone  3-4

Table 3.3      Estimate of Amount of ACM Weather Cladding  3-5

Table 4.1      Summary of Analytical Results – Soil Samples  4-7

Table 4.2      Summary of Analytical Results – Groundwater Samples  4-13

Table 4.3      Actions Required Post Demolition  4-20

Table 5.1      Noise Standards for Daytime Construction Work  5-2

Table 5.2      Representative Noise Sensitive Receivers  5-3

Table 5.3      Estimated Distances from Chimneys  5-3

Table 5.4      Base Suite of Demolition/Construction Plant 5-4

Table 5.5      Base Suite of Soil Remediation Construction Plant 5-5

Table 5.6      Predicted Unmitigated Noise Levels from Demolition  5-5

Table 5.8      Revised Suite of Demolition and Ground Remediation Plant 5-8

Table 5.9      Predicted Mitigated Noise Levels from Demolition of Buildings other than Chimneys  5-9

Table 5.10     Predicted Mitigated Noise Levels from Demolition of Chimneys Only  5-9

Table 5.11     Predicted Mitigated Noise Levels (Ground Remediation) 5-10

Table 6.1      Representative Air Sensitive Receivers  6-1

Table 6.2      Hong Kong Air Quality Objectives (mg/m3) (a) 6-2

Table 7.1      KTCDA Principal Demolition Products  7-5

Table 7.2      Summary of Waste Management Impacts  7-7

Table 8.1      Schedule of Impacts and Mitigation Measures  8-3

 

List of Figures

Figure 1.1         Kennedy Town CDA Locality Plan

Figure 2.1         Kennedy Town CDA Sensitive Receivers & Constraints

Figure 2.2         Kennedy Town CDA Outline Zoning Plan

Figure 2.3         Typical Perimeter Noise Barrier

Figure 2.4         External Working Platforms KTCDA Chimneys

Figure 4.1         Kennedy Town CDA Borehole Locations

Figure 4.2         Contaminated Locations Requiring Clean Up

 

List of Appendices

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

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

Appendix C    Water Quality Standards

Appendix D    Hazards & Safety Requirements

Appendix E     Environmental Outcome Profile

 

 


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

CSTG

Cadogan Street Temporary Garden

CSL

Registered Asbestos Consultant

DCDB

Draft Code of Practice for 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

FEHD

Food and Environmental Hygiene Department

G I/C

Government, Institutional/Community

GDBL

Gin Drinker’s Bay Landfill

HEC

Hong Kong Electric

HOKLAS

Hong Kong Laboratory Accreditation Scheme

IAR

Initial Assessment Report

KTA

Kennedy Town Abattoir

KTCDA

Kennedy Town Comprehensive Development Area

KTIP

Kennedy Town Incineration Plant

MTIA

Marine Traffic Impact Assessment

NCO

Noise Control Ordinance

NSR

Noise Sensititve Receiver

NWFB

New World First Bus

PCDD / PCDF

Dioxins and Furans

PCWA

Public Cargo Working Area

PFBP

Public Fill Barging Point

PAC / PAH

Poly Aromatic Hydrocarbons

PME

Powered Mechanical Equipment

PPFS

Preliminary Project Feasibility Study

PQA

Preliminary Quantitative Assessment

RAC

Registered Asbestos Contractor

RAP

Remediation Action Plan

R7

Route 7

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

URA

Urban Renewal Authority

WDO

Waste Disposal Ordinance

WP1

Working Paper 1


1.                  Introduction

1.1              Background to the Study

1.1.1          The 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 Proposed Kennedy Town Comprehensive Development Area (KTCDA).  A study brief (ESB-023/98) 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 Area (under Agreement No. CE 15/99).  The detailed technical requirements of the EIAO SB (ESB-023/98) require assessment of specific impacts associated with air quality, noise, waste management, land contamination, hazard to life, environmental monitoring and audit.  Air quality and hazard assessments are required only in the event that a blasting methodology was adopted for the demolition.  Impacts on landscape, ecology, water quality, historical and cultural heritage, land use, agriculture and fisheries are not identified 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 Kennedy Town Incineration Plant (KTIP) site has been decommissioned and requires demolition.  There is an animal carcass incinerator at Kennedy Town Abattoir (KTA) that remains temporarily in operation although this will also require decommissioning.  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 requiring study as required under the SB.  The preferred demolition methods have been agreed and noise 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 the project and the elected demolition method will not include blasting techniques.  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 asbestos and land contamination assessments are therefore presented in summary in this EIA.

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.  At an early stage of the study a Working Paper (WP1 on Preferred Demolition Methodology) was presented and endorsed by the First Steering Group Meeting (1st 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.  Blasting will not be used in the demolition process.

1.1.5          The KTCDA is surrounded by residential development and other sensitive uses (Figure 1.1).  The risks, hidden costs and knock on effects of implementing any proposal which would include blasting techniques for the felling of the chimneys or the main building structures make such options unattractive.  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 is that non-blasting demolition methods should be used for the demolition of Kennedy Town Comprehensive Development Area.

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, and remediation of contaminated ground, within the proposed Kennedy Town Comprehensive Development Area (KTCDA) 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, assesses 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 the demolition works, due to the need to protect sensitive receivers, surrounding infrastructure or facilities.  The summary establishes requirements that have been identified and which constrain the way the proposed Project is executed including 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  Noise.

·               Section 6  Air Quality.

·               Section 7  Waste Management.

·               Section 8  Environmental Monitoring and Audit.

·               Section 9  Conclusions and Recommendations.


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

2.1              Study Area KTCDA

2.1.1          The proposed Kennedy Town Comprehensive Development Area (KTCDA) is situated next to Victoria Road and Cadogan Street, Kennedy Town, and adjacent to Victoria Harbour, with a Site area of about 34,000 square metres (Figure 2.1).

2.1.2          The KTCDA comprises several elements as well as the Kennedy Town Incineration Plant (KTIP).  The main operations at the Kennedy Town Abattoir (KTA) ceased and relocated to new facilities at Sheung Shui in the autumn of 1999.  The KTA includes an incinerator for disposal of animal carcasses and waste that is managed by EPD.

2.1.3          Part of the former EMSD Depot that forms part of the KTCDA has been leased to New World First Bus (NWFB) for bus maintenance and refuelling, under a short-term tenancy.  The remainder is leased as a car / lorry park (CP).  These facilities will remain in operation until Site possession is required for the project.

2.1.4          The former Kennedy Town Wholesale Market has been relocated and this area has been recently remodelled as a park and sitting out area adjacent to Victoria Road.  This is known as the Cadogan Street Temporary Garden (CSTG).

2.1.5          Urban Services DepartmentFood and Environmental Hygiene Department (FEHD) have a refuse collection point (RCP) between the park and the abattoir at Sai See Street.

2.1.6          At this stage the KTCDA includes:

·               Kennedy Town Incineration Plant (KTIP);

·               Kennedy Town Abattoir (KTA);

·               New World First Bus Depot (NWFB);

·               Car / lorry park (CP);

·               USD FEHD Refuse Collection Point (RCP); and

·               Cadogan Street Temporary Garden (CSTG).

2.1.7          The structures to be demolished are summarised in Table 2.1.

2.1.8          The KTCDA was recommended for future private housing development in the “Planning and Engineering Study for the Redevelopment of Mount Davis Cottage Area and Kennedy Town Police Married Quarters” (Agreement No. CE 52/97), completed in May1999.  Under that study the Open Space and Refuse Collection Point were proposed for relocation within the redevelopment.

2.1.9          The proposed Kennedy Town Development and Route 7 (R7), a strategic road link between Kennedy Town and Aberdeen, are located just to the north of the KTCDA Site although the exact extent of the Kennedy Town Development and alignment of R7 is not yet confirmed.  A further planning and engineering study to address some major issues, including the Kennedy Town Development and alternative road alignments for R7, is currently being considered by Government.  This further study may alter the future land use of the KTCDA.

2.1.10      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 start date is tentatively scheduled for late 2003.  Experience of other demolition sites and consultation with local contractors suggests that a twelve month programme for the demolition would be sufficient.  The soil remediation programme would follow the demolition and would last an additional six to eight months based on the current findings of the ground contamination investigation.

Table 2.1         Structures to be demolished at KTCDA

Building

Brief Description

KTIP Chimneys

Two reinforced concrete chimneys, 60m high, 3.5m in diameter.

KTIP Building

Reinforced concrete structure of approximately 3,025m² on plan

Refuse Pier

Kennedy Town Abattoir

5-storey reinforced concrete structures of approximately 9,500m² on plan, including,

Reception Pier

E & M Services Department Building

Boiler House and Carcass Incinerator Building.

One reinforced concrete chimney, 25m high, 3m in diameter.

New World First Bus Depot

Offices and Vehicle Inspection Bays. Overall size is approximately 600m² on plan.

Diesel storage tank and lubrication oil stores.

Hong Kong Electric Sub Station

Single Storey Transformer House (adjacent to lairage)

Cadogan Street Temporary Garden

Open landscaped area with street lighting and sitting areas

Sai See Street Refuse Collection Point

Prefabricated steel and concrete structure, single storey. *

                *See Section 2.2

2.2              Sensitive Receivers

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 the SRs and infrastructure on demolition methods.  The implications for sensitive locations of explosive demolition are noted and these have been fully discussed in Appendix A.  Sensitive receivers and other constraints are shown in Figure 2.1.  The Outline Zoning Plan for the area is presented in Figure 2.2.

Sensitive Receivers at KTCDA

Residential, Government, Institutional and Community

2.2.2          Residential, Government, Institutional and Community uses surround the KTCDA Site and many are elevated and overlook the Site.  The nearest rank of sensitive receivers is discussed below.

·               Kennedy Town Police Married Quarters currently overlooks the Site.  The premises are scheduled to be vacated but parts of the buildings will potentially be occupied up to March 2002.

·               The Mount Davis Cottage Area has been vacated.

·               The Housing Society development at Ka Wai Man Roadmid.

·               There are occupied residential buildings at Cadogan Street including Centenary Mansion.

2.2.3          Other premises in the low-rise blocks in Cadogan Street have been demolished.

2.2.4          Premises in the low rise blocks in Cadogan Street (south of Victoria Road) and two high rise blocks (Sai Wan New Mansion and Cheung Kat Mansion) near the URA development, will remain in operation by the time demolition of KTCDA takes place.

2.2.5          Manhattan Heights high rise development at Kennedy Town New Praya overlooks the Site and is now occupied.  As such it is considered as a sensitive receiver.

2.2.6          There are other residential blocks further west along Victoria Road (e.g. Huncliff Court) that would be shielded by the intervening structures such as the China Merchants Wharf Godown and other industrial buildings on Victoria Road.

2.2.7          There are Government, Institutional and Community uses at St Luke’s Church School, St Luke’s Settlement, Jockey Club Clinic, Victoria Mortuary and the Bayanihan Centre.

2.2.8          St Luke’s Church School on Ka Wai Man Road and both St Luke’s Settlement and Jockey Club Clinic will remain in operation at the time of demolition for KTCDA.

2.2.9          The Bayanihan Centre on Victoria Road is a training and support facility for Philippine overseas workers that is open seven days per week and it is assumed this will remain in operation at the time of the demolition of KTCDA.

Other Sensitivities near KTCDA

NWFB

2.2.10      The New World First Bus Depot may require relocation  prior to the demolition.  However this is not material to the EIA as it is not defined as an SR.  Nevertheless the project proponent may need to liase with NWFB so that they may make provisions for these facilities at a later stage.  Diesel fuel storage tanks and other lubrication oil storage at NWFB are dealt with as part of the land contamination assessment and remediation action plan.

RCP

2.2.11      It has been suggested by the Food and Environmental Hygiene Department that the RCP at Sai See Street should be maintained throughout the demolition process.  The area of Sai See Street leading up to the RCP and the RCP itself would need to be excluded from the demolition in the usual way by means of a perimeter noise barrier running around Sai See Street and the RCP.  Such exclusion would make manoeuvring more difficult as the excluded area would effectively bisect much of the southern part of the Site and restrict transit from east to west.  Whereas it is not possible to establish, in detail, the possible impact of this on the demolition programme, common sense suggests that whereas reasonable areas would remain for manoeuvre in most other parts of the Site, the overall impact would not necessarily make major impacts on the programme.  However in order to simplify the demolition works the preference (on demolition grounds alone) would be to relocate the RCP and include the RCP site in the demolition site, unless an alternative location cannot be found.

2.2.12      The RCP adjacent to the CSTG in Cadogan Street is a lightweight prefabricated structure that could be relocated if necessary.  However LCSD have commented that the CSTG should remain open if at all possible to avoid the expense of reprovisioning.  The retention of the RCP at its present location may not necessarily be the most convenient arrangement for the demolition (as it would mean retaining the access along Sai See Street).  However, the access road and RCP area should be able to be excised from the demolition site without major inconvenience to the demolition process.  As there are no buildings immediately adjacent to the RCP routine procedures and precautionary measures carried out in line with the Draft Code of Practice for Demolition of Buildings (DCDB, Buildings Department 1998) will avoid impacts on the operation of the RCP.  This can take place within the routine for good overall project management of a demolition under the Hong Kong guidelines.

Road Traffic

2.2.13      Road traffic access must be maintained for residential and commercial uses at Kennedy Town.  There are potential concerns about the potential impact of traffic to and from the demolition site on the local network.

2.2.14      Access must be maintained for commercial uses at China Merchants Wharf and Godown, the Kennedy Town public transport terminus, Victoria Public Mortuary, industrial buildings, residences on Victoria Road, the petrol station on Victoria Road and the Island West Refuse Transfer Station.

2.2.15      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.  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.  It is considered that this level of additional traffic could be absorbed into the surrounding network without significant impact (Section 6.4.1 refers).

Marine Traffic

2.2.16      An alternative method would be to use barges to remove waste in order to reduce overall road traffic impacts.  However in such a case, access would need to be Access must be maintained for vessels accessing the pier at China Merchants Wharf and Cadogan Street wharves and interference to the Victoria Harbour marine traffic must be minimised. Marine Department indicated that it would be preferable to avoid impacts in this busy marine area.  As  Although local aassessments indicate that additional waste disposal road vehicles could be absorbed into the surrounding road network without undue inconvenience, marine access is not required., it has been suggested that barges could be used to remove waste in order to reduce overall road traffic impacts.  Such a proposal would require a Marine Traffic Impact Assessments (MTIA) and is outwith the SB

Other Issues

2.2.17      The revised alignment for Route 7 and the extent of the Kennedy Town Developments are currently under review but at present the programme of these developments is unlikely to be advanced before the target completion date for demolition of KTCDA.  At this stage these proposals are not thought to have any impact on the Project.

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 KTCDA.   Site investigations have shown asbestos containing materials (ACM) are present at KTCDA (Section 3).  Therefore the preferred method of demolition should adopt non-blasting approach and implosive demolition using a blasting approach has been ruled out as an option for demolition.  The asbestos investigation and abatement plans are described in detail in the dedicated Asbestos Study Report.

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 can be assumed to be used at KTCDA.

Wrecking Ball

2.3.4          This method is generally suitable for dilapidated buildings but would not be applicable in this case where the clear space to the edge of the Site is limited in places and structures have substantial steel reinforcement.

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 which are effective for all structures and can reduce vibration, noise and dust.  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.  However for the purpose of the environmental assessment these techniques are not assumed to be adopted in order that a worst possible case scenario is assessed.

Reception Piers

2.3.6          The recommended choice of demolition methods for the marine reception platforms and piers is top down method using saw cutting and lifting, in line with the DCDB, which will avoid the disturbance of any marine mud.

Preferred Methodology

2.3.7          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 use of jack-hammers and hydraulic breakers is efficient and noise and dust impacts can potentially be controlled by a range of practical mitigation measures (e.g. noise barriers, dust control) familiar to the construction industry in Hong Kong.  In addition, 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 the preferred method of demolition must adopt non-explosive approach.  The asbestos investigation and abatement plans are described in detail in the dedicated Asbestos Study Report that has been reviewed by EPD.

Removal of Waste

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

Marine Barges

2.3.9          The use of barges could reduce overall road traffic impacts, however loading at the waterfront would introduce the possibility of dust and waste being dropped into the sea.  Whereas there are reception piers at the waterfront which could be used as barging points the potential for loss of waste and consequent water pollution from these sources can be eradicated by the use of other means to transport waste.  Such access would also be complicated by the need to avoid vessels accessing the pier at China Merchants Wharf and Cadogan Street wharves.  The Marine Department has indicated that interference to the Victoria Harbour marine traffic must be minimised and given the potential to use road vehicles to transport waste, the marine route is not favoured.

Road Traffic

2.3.10      The volume of demolition material requiring off-site is estimated to comprise 19,000m3 concrete and 330,000kg steel reinforcement.  In addition, small amounts of non-inert materials (e.g. wood used in building fabrication) would also require off-site disposal.  It is estimated that the up to about forty lorries per day would be required to remove such material from the Site.  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.  Background traffic moving in the area (based on the 1999 Annual Traffic Census) is greater than ten thousand vehicles per day and assessment has indicated that this level of additional traffic could be absorbed into the surrounding network without significant impact (i.e. predominantly Kennedy Town New Praya and Victoria Road, Section 6.4.1 refers).  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.  Additional road vehicles for waste disposal could therefore be absorbed into the surrounding road network without undue inconvenience.  Therefore disposal of waste by road is the preferred option.

2.3.11      It is anticipated that by the time demolition works commence the Kai Tak Waste Recycling facility will have completed commissioning and will be available to accept C&D wastes.  In addition, it is understood that the Sai Ying Pun public fill barging point will also be available for the foreseeable future.

2.4              General Approach to Demolition of Buildings and Structures at KTCDA

General Approach

2.4.1          This section seeks to demonstrate some of the more general procedures for demolition, which would be likely to apply to KTCDA.  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 of the selected demolition contractor(s) may not necessarily adopt the precise methodology proposed in Appendix A and summarised here, the consultants believe that general characteristics of the methods are appropriate.  Blasting will not be used and other conventional methods for Hong Kong 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) which will also need to be observed at the detailed design stage.

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

Hoarding and Site Access

·               Typical perimeter noise barriers are shown in the indicative hoarding plan (Figure 2.3).

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

·               All structures are totally within the proposed Project Site and access would be controlled by security guards.

·               No members of the public or unauthorised person 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, storey by storey, having regard to type of construction.

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

·               All asbestos containing materials (ACM, particularly any ACM weather cladding, 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).

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

·               All debris to be removed at frequent intervals and stockpiles should not be allowed to build up.  Waste to be removed on a daily basis.

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

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

·               Determine where temporary support will be needed upon advice of the Site Engineer/AP/RSE.

2.5              Principles of Chimney Demolition at KTCDA

Access

2.5.1          The main Site would be protected by security personnel and a high (5.5m) perimeter noise barrier (hoarding) such that the public would be totally excluded from the Project.

2.5.2          The area beneath the chimneys 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 structures.

General Approach

2.5.3          The principle of the demolition procedure shall be that the chimney would be cut into pieces and moved to ground level inside the chimney.  This method would ensure that full control the fall of the debris and that the pieces of reinforced concrete are not left to free fall outside the chimney (Figure.2.4).

Upper Chimneys

2.5.4          The principle of the demolition procedure for the upper portion of the chimneys (i.e. say 10metres from ground level or greater) is that the chimneys will be broken into small pieces on the spot by operatives using hand held tools.  They would work from working platforms external to the chimney (Figure 2.4).  Hydraulic breakers would be used for the remaining lower portions of the chimneys.

2.5.5          Prior to the commencement of the demolition work, loose sand will be placed on top of the existing ground around the chimneys to receive any small pieces of light debris that may fall.  To facilitate the access of the excavators for the removal of debris, an access ramp will be formed.  The vertical opening (former fan duct connection point) near the base of the stack would be blocked when demolition is in progress.  This portal would be opened for removal of debris after completion of daily demolition work.  To reduce dust, damping down would be a routine procedure at this stage.  The above mentioned method of removal of debris is only applicable to the demolition of the upper portion of the chimneys.

Lower Chimneys

2.5.6          For demolition of the lower portion, 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.

2.5.7          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

2.5.8          The area surrounding the chimney will be secured and all necessary barricades erected.  Only authorised personnel will be allowed into the area.  A steel external working platform system will be erected to surround the upper portion of the chimney, i.e. greater than 10 metres above ground level.  The maximum distance between the floor levels of the working platforms will be two metres.  Steel access and steel ladders will be constructed from ground level to the top of each chimney, with proper handrails (Figure 2.4).

Sequence of Operations

2.5.9          The demolition sequence would involve the construction of a series of working platforms around the outside of a chimney.  Workers would work from the top most platform to remove the chimney structure with the debris directed into the lower portion of the remaining chimney.  This would involve the following steps.

·               All required preparation work and safety measures would be installed.  The area surrounding the chimney would be made secure and all necessary barricades erected.

·               Safety netting and tarpaulins would be installed to enclose the location at which demolition work is in progress (i.e. the external boundary of the steel working platform from platform floor level to one meter above the top edge of the remaining chimney wall).  Checks would be made to ensure no gaps were present between floorboards and between the kickboards at the front edge of platform and the external surface of the chimney, so as to avoid broken pieces falling out beyond the netted working platform.

·               The portion of the wall from say 0.3m above the floor level of the working platform to the top of the chimney will be demolished by operatives working on the platform using hand held pneumatic breaking tools to break the existing chimney concrete into small pieces.  Work would proceed from top working towards the lower level.  The steel reinforcement exposed in the process would be cut by flame and lowered to ground.

·               After completing the work at one level, operatives would descend to the working platform just below and remove the components of the upper platform carefully.  Demolition at the lower platform level would then proceed, safety nets will be installed in the same manner as described above.

·               The debris would be cleaned out from the platform daily (each afternoon/evening) to avoid accumulation of debris.

·               The same sequence of work above would be repeated until the chimney had been lowered down to approximately 10metres, a level within the reach of mobile hydraulic breakers at ground level.  The lower portion would be removed by these means.

Duration of Demolition

2.5.10      The buildings and chimneys at KTCDA 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.

2.5.11      It is estimated that 12 months would provide adequate time for the required scope of demolition based on the above methodology.  This concurs with independent advice obtained from experienced demolition contractors.  The demolition of chimneys would follow demolition of the main buildings and other site offices/storage buildings.  It is estimated that a further six to eight months would be required to execute the Remedial Action Plan for contaminated soil based on the current findings of the ground contamination investigation.

2.5.12      The demolition programme has yet to be established in detail but is anticipated to commence in late 2003.  The implementation of acoustic mitigation measures such as use of silenced equipment and acoustic barriers is routine in Hong Kong nowadays.  Likewise there will be statutory requirements for mitigation of fugitive dust emissions under the APCO and effluents under the WPCO.  Whereas these should not have any significant impact on the programme, providing the requirements are recognised early as will be the case through the environmental permit, the contractors will be expected to allow for such resources in their responses to tender.


3.                  Asbestos Control

3.1              Site Location and Description

3.1.1          This section summarises the work carried out to date at KTCDA to identify potential asbestos containing material (ACM).  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.

3.1.2          The premises are 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 the purpose 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.

3.1.3          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.

Kennedy Town Incineration Plant

3.1.4          The remaining structures of the main building, offices and chimneys appear to be essentially unmodified since the end of the decommissioning and dismantling (c1993).  Whereas no records could be obtained it is known that all ACM was removed from the incinerators, boilers and precipitators, etc., prior to dismantling.

3.1.5          No maintenance of the external chimney ladders has taken place since the closure of the plant and it was not possible to establish that the ladders are in a safe condition, therefore the tops of the chimneys have not been examined.  Whereas the available plans do not show any ACM in the chimney top structures it will be prudent to investigate the chimney tops at a later stage in line with agreed demolition procedure.  When the contractors have built the working platforms (scaffold) external to the chimneys, and prior to any demolition it will be necessary for investigation to take place and for the AIR and AAP to be amended as necessary if ACM is identified.  Adequate time shall be allowed in the demolition programme to ensure that any ACM, subsequently identified at currently inaccessible areas (e.g. Chimney tops) is properly abated. 

Kennedy Town Abattoir

3.1.6          No records of previous maintenance were made available, however some records of the earlier asbestos abatement in the main abattoir buildings were obtained from the contractor who originally conducted the work.  This reputable contractor is now an RAC.  Extracts from these records were forwarded to EPD for information purposes.  These records indicate that all ACM was removed from the main abattoir plant in a series of abatement contracts in 1990.  The areas involved included all boilers and pipework in the main plant.  The animal carcass incinerator was not included although the ductwork serving the chimney was included in the abatement work.  Thus the majority of ACM present in the plant was removed prior to this investigation.  It was not possible to access the HEC substation therefore the HEC transformer compound has not been examined.  Whereas the available plans do not show any ACM in the transformer compound it will be prudent to investigate this area at a later stage in line with agreed demolition procedure.  Adequate time shall be allowed in the demolition programme for to ensure that any ACM, subsequently identified at currently inaccessible areas (e.g. transformer compound) is properly abated.

New World First Bus Depot, Car Park and Cadogan Street Temporary Garden

3.1.7          No records of previous maintenance were available for the NWFB, CP and CSTG.

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, and expertise, and qualified assumptions based upon an intricate knowledge of the Site layout.  Plans and suitable diagrams of the Site have been made available.  This enabled the visual identification of the remaining details of which are presented in the Asbestos Study Report and summarised below.

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

3.2.3          In conducting the asbestos investigation the Site was examined adopting a systematic approach whereby each individual functional zone was inspected.  For ease of identification each functional zone was designated by reference to the former Site operation in relation to the Site layout.

Access

3.2.4          It is noted that all remaining ACM on the Site is inaccessible to the general public.  In general, the operation of the KTCDA is unlikely to have given rise to any residual contamination of the buildings with ACM dust or fibre.  Dust sampling undertaken around the open areas of the Site was undertaken to check that no ACM dust and debris has accumulated around the potential ACM components.  As far as possible all potential ACM has been sampled as part of the Site Investigation procedure.  Where present, ACM is not necessarily a hazard to 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 for KTCDA.


Table 3.1         Main Locations for ACM Investigation at KTCDA

Building

Brief Description

KTIP Chimneys

Bases of two reinforced concrete chimneys, 60m high, 3.5m in diameter.

KTIP Building

Reinforced concrete structure of approximately 3,025m² on plan ACM Cladding

Refuse Pier. 

Kennedy Town Abattoir

5-storey reinforced concrete structures of approximately 9,500m² on plan, including,

Blood and Bone House (Main Building).  Potential ACM Insulation pipes and boilers.

Reception Pier. 

E & M Services Department Building (at KTA)

Boiler House and Carcass Incinerator Building.

One reinforced concrete chimney, 25m high, 3m in diameter.

Other Buildings.

New World First Bus Depot

Offices and Vehicle Inspection Bays.  No potential ACM on walkthrough inspection .

Hong Kong Electric Sub Station

Single Storey Transformer House (requires checking)

Cadogan Street Temporary Garden

(All structures removed previously by Government. No ACM Suspected)

Sai See Street Refuse Collection Point

(New Construction. No ACM Suspected.)

 

3.3              ACM to be Removed

3.3.1          The Premises were suspected to contain ACM materials and the CSL has inspected all potential ACM materials (see AIR).  The materials to be removed are summarised in Table 3.2.

KTIP

3.3.2          There is ACM paint coating to the cladding that covers most of the KTIP main building.

3.3.3          There is ACM adhesive on the floor tiles within the mastic adhesive under-layer.  Floor tiles in KTA are similar.

3.3.4          There are ACM deposits at the base of Chimney A and the deposits at Chimney B are friable but these materials are compacted and within the chimney.

KTA

3.3.5          ACM gaskets are present at flanges of the hot water pipes.

3.3.6          ACM cloth arc shutes are present in fuse boxes on the lairage roof.

3.3.7          ACM corrugated cement sheeting is present at the lairage animal reception area (waterfront).  An ACM cement blackboard is present at the canteen office at the lairage roof.

3.3.8          ACM bitumen weather protection is present at the tops of the flues of the animal carcass incinerator chimney (KTA).

3.3.9          ACM woven gaskets are present at the blood cookers and meat boilers.

3.3.10      The ACM linings to the animal carcass incinerators are within the incinerators and not readily accessible.

3.3.11      Table 3.2 summarises the asbestos investigation and assessment.


Table 3.2         Areas of ACM Identified by Functional Zone

Functional Space

Homogenous Material

Location

Removal prior to main civil demolition *

Homo-genous Area

Estimated Quantity Approx.
(m3)

Friability

Condition

Use

Accessibility

Asbestos Material

KTIP Main Building

Corrugated Metal Sheeting

Throughout Main Building

No*

Weather Cladding

Total  1000m3

(see Table 3.3)

No

Fair to Good

Weather Protection

Low

Type 1

KTIP Chimneys

Asbestos containing deposits

Deposits at base of Chimneys A and B

Yes

Heterogeneous deposits

Two 30cm deep 3m diameter circular areas  chimney base Total <3m3

Yes

Poor but compacted

Debris (source unknown)

Low

Type 3

KTIP Office Block

Floor Tile / Adhesive

Offices

Yes

Floor Tile

20m x 6m

No

Fair to Good

Flooring

Low

Type 1

KTA Building Offices

Floor Tile / Adhesive

Offices

Yes

Floor Tile

50m x 10m

No

Fair to Good

Flooring

Low

Type 1

KTA (lairage roof)

Asbestos Cloth

Fuse Boxes

Yes

Asbestos Arc Shute

5cm x 3cm wide cloth pieces. Total <2.m3

Yes

Good

Arc Shute

Low

Type 2

KTA Cattle Reception Area

Asbestos Cement Roof

Parts of roofing at waterfront.

Yes

Roofing

3m wide x 5m long. 

Total <20m3

No

Good

Weather Protection

Low

Type 1

KTA Liarage Canteen Office

Asbestos Blackboard

Office.

Yes

Blackboard

1m wide x 3m long. 

Total <5m3

No

Good

Blackboard

Low

Type 1

KTA Chimney Flues

ACM in Bituminous Asphalt Coating

Tops of five flues.

No*

Weather Protection

2m x 1m x 5mm deep coating on each flue. 

Total <2.m3

No

Fair

Weather Protection

Low

Type 1

KTA By-Products Plant

Asbestos Woven Gasket

Meat Cookers and Blood Boilers

Yes

Asbestos Gasket

5cm wide x 3m long (sixteen circular pieces).

Total <2.m3

Yes

Good

Sealing Material

Low

Type 2

KTA Animal Carcass Incinerator

Asbestos milboard

Animal Carcass Incinerator

Yes

Insulation

5m wide x 3m long (six sides of incinerator).

Total <5.m3

Yes

Poor

Insulation

Low

Type 3

*              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         Estimate 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 and Walls

30m x 50m

1500

1500

 

South Side

Roof and Walls

30m x 70m

2100

2100

 

North Side

Roof and Walls

30m x 70m

2100

2100

 

West Side

Roof and Walls

30m x 50m

1500

1500

 

TOTAL

 

 

 

7200

 


3.4              Justification of Methods

3.4.1          The 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 generally appears to be in a fair to 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.  At this stage the precise details of abatement process for each of the identified material have been determined as far as possible.  Some further investigation will be required at the detailed design stage. 

3.4.2          The Study Brief issued by CED assumes that any ACM present in the chimneys and superstructures 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 and duplication of effort can be avoided if both asbestos contractors and civil demolition contractors work in tandem.  EPD must be notified 28 days prior to the commencement of the abatement works.  The contractual arrangements for the demolition have yet to progressed and further fine tuning of the abatement methods and recommendations for the dovetailing of asbestos abatement works with general of demolition may be necessary at the detailed design stage.  The methods presented in this Asbestos Abatement Plan provide sufficient detail without ruling out the possibility of some adjustment at a later stage.  In the event that adjustments are required these shall be notified and agreed with EPD 28days prior to the commencement of the abatement works.

3.4.3          The removal process for the ACM from the base of the chimneys, the fibrous gaskets to the meat and blood boilers and the linings remaining on the animal carcass incinerator has the potential to liberate significant quantities of asbestos fibre.  Therefore full containment methods are warranted for these items and removal methods will be in line with the code of practice for Asbestos Control, Asbestos Work Using Full or Mini Containment Method and supervised accordingly.

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

Kennedy Town Incineration Plant

3.4.5          The ACM paint coating to the cladding covers most of the KTIP 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.  The coating which contains the ACM has resisted weathering.  The paint is not friable and 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.

3.4.6          The ACM adhesive on the floor tiles at KTIP and KTA are in a similar condition.  The ACM adhesive for the vinyl floor tiles can 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, 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.

3.4.7          The loose ACM deposits at the base of chimney A and the deposits at chimney B are friable but these materials are compacted and within the chimney, not readily accessible and unlikely to release fibre unless deliberately disturbed.  The CSL has concluded that the ACM to be removed appears to be in a reasonable condition for the time being but controlled conditions will be required for disposal.  Some of the ACM identified is potentially friable and although not difficult to extract and there are significant quantities.  The removal process for ACM deposits at the base of the chimney has the potential to liberate significant quantities of asbestos fibre and it is evident that full containment methods are warranted for this part of the chimney. It is proposed that a full containment be erected around the base of the chimney and the ACM removed in line with code of practice on Asbestos Control Using Full Containment.  Whereas further investigation at the chimney tops will be required at a later date (after the main civil demolition contractor has built the scaffolding) further abatement at the upper portions of the chimney may be required depending on the results of additional investigations.  The abatement requirements for these locations will be worked out with the civil demolition contractor and the asbestos contractor to the satisfaction of EPD at the detailed design stage.

Kennedy Town Abattoir

3.4.8          The ACM gaskets at the hot water pipes are not friable and only exposed at the edges. 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 numbers of gaskets involved and 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 location of the ACM in a designated gasket is such that as the demolition proceeds and the pipes are dismantled, the ACM within the gaskets can remain undisturbed and removal can be accomplished as the pipework is dismantled.  When the main civil demolition contractor reaches each section of pipe the metal flange sections around the gaskets can be unbolted and the excised gasket material can be wrapped ready for disposal.  At ground level they would be handled carefully so as not to bend or crack the gaskets (which may release fibres) and be placed in drums or wrapped ready for disposal.

3.4.9          The ACM cloth arc shutes at the fuse boxes are friable but these materials are present in very small amounts within the fuse boxes, which is not readily accessible and unlikely to undergo further major dilapidation unless deliberately disturbed.  The whole fuse box can be extracted and the undisturbed ACM within can be wrapped ready for disposal.  At ground level it would be lowered into a segregated area and wrapped ready for disposal line with code of practice on Safe Handling of Low Risk ACM.

3.4.10      The ACM corrugated cement sheeting at the lairage animal reception area and the ACM blackboard at the canteen office are not friable and there is little chance of fibre release if left undisturbed.  Any ACM is effectively encapsulated within the cement layers and the sheets and the blackboard can be easily dismounted from the supporting brackets.  Such methods are unlikely to cause the sheeting to crumble in such a way as to release the ACM fibres. Such cement sheeting will require segregation, but work can be carried out in line with code of practice on Safe Handling of Low Risk ACM.

3.4.11      The ACM bitumen weather protection at the top of the animal carcass incinerator chimney (Chimney C, KTA) is not friable there is little chance of fibre release if left undisturbed.  All ACM is effectively encapsulated within the mastic adhesive underlayer and can be easily prised from the chimney tops 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 tops of the individual sections of the flues will require segregation, work can be carried out in line with code of practice on Safe Handling of Low Risk ACM.  Scaffolding and tarpaulins will be erected for the general demolition but additional wind barriers will be required for work at such height, in order to ensure removed sections of ACM are not dispersed by wind.  A similar approach may be required for any ACM identified at the top of Chimneys A and B at KTIP.

3.4.12      The ACM woven gaskets, at the blood cookers and meat boilers, although friable are only exposed at the edges and there is little chance of fibre release if left undisturbed.  Although the gaskets are almost pure chrysotile, experience suggests that ACM present is in a relatively compressed state such that if the gasket flange is released slightly the ACM can be wetted and the gasket can be easily prised from the flange using scrapers and moderate force.  Such force and methods are unlikely to cause the gaskets to crumble in such a way as to release significant quantities the ACM fibres, however the reaction of the gaskets when release cannot be guaranteed.  Therefore the areas around the individual blood cookers and meat boilers will require full containment for work to be carried out in line with code of practice on Asbestos Control Using Full Containment.

3.4.13      The ACM linings to the animal carcass incinerators are friable but these materials are within the incinerators and not readily accessible.  They are unlikely to undergo further major dilapidation unless deliberately disturbed.  The CSL has concluded that the ACM to be removed appears to be in only a fair to poor condition and although unlikely to result in the release of asbestos fibres, unless deliberately disturbed, significant fibre release could result at the dismantling stages.  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 animal carcass incinerators.  ACM shall be removed in line with code of practice on Asbestos Control Using Full Containment (i.e. full containment around the incinerators).

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 on the animal carcass incinerator until such time as it is decommissioned or 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.

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.  The 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 Contractor (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 as descried in Section 4.

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).  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 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          The RAC 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          After the statutory 28 days notice period has elapsed following the acceptance of the AAP, a minimum of one-week advance notice will be given to the RAC to commence the work on the Site.

3.6.1          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.

3.6.2          At this stage the Registered Asbestos Contractor (RAC) has not been appointed.  The detailed programme for the works may be affected by interfacing between the RAC (possibly sub-contracted) and the main civil demolition contractor.  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.

3.6.3          The final asbestos abatement programme will be passed to EPD at least 28 days prior to the commencement of abatement works.  The programme shall provide details of the asbestos abatement work and the interface between the RAC and the main civil demolition contractor in order to demonstrate how the ACM will not be disturbed by unauthorised parties.  Any subsequent amendments will also be passed to EPD prior to the reprogramming of abatement works and a monthly report shall be prepared by the RAC so as to keep the authorities up to date with the works. Whereas it is not expected that asbestos fibre would be liberated from the asbestos abatement works, EM&A for asbestos fibre has been conducted at the boundary on Government sites and this is recommended at the Site boundary to provide reassurance that the asbestos fibre criteria are not be exceeded.

3.7              Regulations, Codes of Practice and Local Requirements

Statutory Obligations and Codes of Practice, etc.

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.


4.                  Land Contamination

4.1              Requirement 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 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 re-development of sites related to certain industrial land uses should 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 manufacture and processing plant; and

·               car repairing / dismantling workshops.

4.1.3          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.  A completed land contamination assessment report, including CAP and CAR/RAP should be submitted before the commencement of any construction 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 EIA Report.  The objectives of the CAR 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 carried out to investigate the extent and nature of land contamination at the Kennedy Town CDA.

4.2              Land Use History

4.2.1          The proposed KTCDA is situated next to Victoria Road and Cadogan Street, Kennedy Town, and adjacent to Victoria Harbour, with a Site area of about 3.4 ha (Figure 2.1).  The existing compound was first used as wholesale market, depot, distillery, squatter area, coal yard, godown and sawmill in the late 1950s.

4.2.2          The main operations at the KTA commenced in 1960s and ceased for relocation to new facilities at Sheung Shui in the autumn of 1999.  The KTA includes an incinerator for disposal of animal carcasses and waste that is managed by EPD.  There is also a purpose built transformer room.

4.2.3          Part of the former EMSD Depot that forms part of the KTCDA commenced in late 1950s.  Recently, it has been leased to New World First Bus (NWFB) for bus maintenance and refuelling, under a short-term tenancy.  The remainder is leased as bus park.  These facilities will remain in operation for the time being.

4.2.4          The former Kennedy Town Wholesale Market has been relocated and this area was remodelled as a public car park in mid 1990s.  In 1999 part of the car park was modified as the sitting out area adjacent to Victoria Road.  This is known as the Cadogan Street Temporary Garden (CSTG).

4.2.5          Urban Services DepartmentFood and Environmental Hygiene Department has also recently constructed a Refuse Collection Point between the CSTG and the Abattoir at Sai See Street.

Description of Existing KTCDA Compound

Site Activities

4.2.6          The KTCDA is currently used for the following activities:

·               maintenance and repair of vehicles;

·               storage of fuel;

·               vehicle refuelling;

·               vehicle parking; and

·               sitting out area; and

·               refuse collection point and access (Sai See Street)..

4.2.7          In addition to the above, former activities included:

·               waste incineration;

·               abattoir;

·               electrical and mechanical equipment maintenance;

·               wholesale marketing;

·               coal yard;

·               sawmill; and

·               distillery.

4.2.8          Hydrocarbons are stored on Site in the form of vehicle fuel, new lubrication oil and waste lubrication oil at the NWFB site and diesel fuel at the KTA site.

4.3              Site Inspection

4.3.1          Site inspection was undertaken by the 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 30 boreholes and the extraction of soil samples from various depths.  Groundwater samples were also taken.

1.1.1A photographic record of the site inspection was presented in the CAP.  These photographs are presented in Appendix A.  A key to the locations and directions of these photographs is presented in Appendix A, Figure 1.

Kennedy Town Incinerator Plant

4.3.2          The KTIP site was decommissioned in the early 1990s and is now overgrown with weeds in many areas.  The Fuel Tanks, Refuse Reception Area, Main (Incineration Plant) Hall, Dust and Grit Collection plant area and Chimneys are now derelict.  Locations of the boreholes are indicated in figure 4.1.

Kennedy Town Abattoir

4.3.3          The KTA is divided into three main blocks.  These are the lairage block, the slaughterhouse block and the refrigeration block.  In addition there is the entrance unit and the boiler house block with a transformed compound.  

4.3.4          The animal carcass incinerator at the plant remains in standby mode, therefore sampling in close proximity active plant is not possible at this stage.  However some locations for boreholes were agreed with EPD, near and under the plant which could have given rise to contamination.  Where it is not feasible to sample in all the preferred locations, a borehole was be made as close as possible to the preferred location.

New World First Bus Depot (NWFB)

4.3.5          The NWFB is divided into three main areas.  These are the maintenance area, the fuel and lubrication areas and the office block.  The depot compound work area has a concrete screed covering to provide a suitable working surface and allow convenient vehicle access and manoeuvring in the maintenance and refuelling areas and also to allow for controlled site drainage.  An above ground fuel tank, located near the entrance to the KTIP, is now used by the NWFB depot.  Sub surface pipes serving the tank will need to be removed.  An above ground lubricating oil storage area is also located near the entrance to the KTIP within the NWFB depot.  There is also a chemical waste storage area located near the exit just within the NWFB depot.

Car Park

4.3.2          The car park area is located adjacent between Sai See Street and the NWFB depot.   There is no storage in this area which is covered with concrete.

Cadogan Street Temporary Garden (CSTG)

4.3.3          The Cadogan Street Temporary Garden (CSTG) occupies the area of the former wholesale market which has recently been redeveloped and landscaped.  This area was formerly a market (since 1945) and then vacant open ground with a concrete covering.  It has also been used as a car park.

Refuse Collection Point

4.3.4          To the north west side of the CSTG is the Sai See Street Refuse Collection Point.

Kennedy Town Incinerator Plant

Fuel Tanks

4.3.4Two fuel tanks were formerly located near the entrance to the KTIP.  The former fuel tank area was bunded.  The main tank has been removed and there is no obvious local contamination beneath the weeds.  (Photo 1).  The second fuel tank is now used by the NWFB depot.  This area is also bunded and there is no obvious local contamination within or adjacent to the bunding.  (Photo 2).  The tanks areas are located on a concrete base and concrete bunds were created around the fuel tanks to control accidental leakage.  There is no major obvious contamination in this area, however since there are no records for inspection a cautious approach will be take and samples will be taken from a borehole (B1) in this area, adjacent to the main fuel tank bund wall Photo 1.  The parameters for analysis will include TPH and BTEX.

Refuse Reception Area

4.3.4The ramps leading up to the Reception Area and the Reception area are concrete (Photos 3 & 5) and there is no obvious significant surface contamination.

Refuse Bunkers

4.3.4The Refuse Bunkers were mostly located above the general site level in order to minimise excavation during construction.  They have a reinforced concrete base and sides.  There is no drainage and that portion below ground level is flooded with rainwater.  It is not possible to identify major contamination at the bottom of the bunkers, due to the present condition.  The refuse bunkers (Photo 4) appear to contain some rainwater, scrap and other deposits which have probably accumulated or been thrown in since the plant was vacated.  The depth of these deposits and the water could not be determined at this stage.  Whereas the possibilities of contamination reaching the soil beyond and below the bunkers seems unlikely as their heavy design (to with old contaminants) has prevented subsequent leakage, further examination of these deposits may be warranted during the site investigation. The potential for contamination of the deposits in the bunker will be examined more closely by extracting samples of the deposits from two bunkers. .  The parameters for analysis will include TPH and BTEX.  HM will also be included to check for any general contamination of the refuse bunkers.

Exit Ramp and Refuse Reception Ground Floor

4.3.4The ramps leading from the Reception Area are also concrete (Photos 6) and there is no obvious significant surface contamination.  The area to the west of the ramp (Photo 7) and the area beneath the Refuse Reception Area is also concrete (former offices and workshops, Photos 8 & 9) and there is no obvious significant surface contamination.

Switchgear Room

4.3.4The switchgear area for the generator room at ground level area is adjacent to the refuse bunkers (Photo 10).  The floor is concrete.  All electrical plant has been removed.  The plant was located on a concrete base with concrete lined cable channels.  There was no significant contamination in this area.

Generator Room

4.3.4The main generator room is shown in Photos 11 and 12.  A close up of the floor is shown in Photo 15.  The floor is concrete with ceramic tiles.  All electrical plant has been removed.  The plant was located on plinths with a concrete base with concrete lined cable channels.  There is some significant oily contamination in this area.  Samples will be taken from a borehole (B2) in this area.  The parameters for analysis will include TPH, PCB and BTEX.

Plant Room

4.3.4The plantroom outside the generator room at ground level is adjacent to the ramp (Photo 14).  The floor is concrete.  All electrical plant has been removed.  The plant was located on a concrete base.  There was no significant contamination in this area.

Transformer Areas

4.3.4The areas are adjacent to the Generator Room at ground level.  There is an indoor room (Photo 16) and an outside plinth (Photo 14).  The ground has a heavy concrete cover and all electrical plant has been removed.  The plant was located on plinths with a concrete base with concrete lined cable channels.  There is no obvious heavy contamination in this area, however there are fissures in the concrete and such contamination could have been weathered away from the surface due to the outdoor location.  Therefore it is proposed to establish a borehole (B3) in this area.  The parameters for analysis will include TPH, PCB and BTEX.

Exhaust and Transfer House Areas

4.3.4The areas are adjacent to the main hall. The roof structure has been removed.  There is an outside plinth (Photo 17).  The ground has a heavy concrete covering and plant has been removed.  There is no obvious contamination in this area and it is not proposed to take samples.

Main Hall

4.3.4The main hall is a high structure (Photo 19) which formerly housed the incinerators, rotary kilns and boilers.  The floor is constructed from reinforced concrete with a steel outer corrugated weather cladding. (Photo 20).  All electrical circuitry has been removed.  There was no obvious contamination, however since this area had significant potential to cause contamination and there are drains and cracks in the concrete a cautious approach will be taken and samples will be taken from six boreholes (B4 to B9) in this area.  These will roughly correspond to the areas which would formerly have been under the incinerators (B4/5, Photo 20/31) ash conveyors (B6/7, Photo 21) and boilers B8/9, Photo 21.  The parameters for analysis will include TPH, PCB, PAH and BTEX possibly from residual fuel oil, lubrication oil or electrical installations.  HM, and PCCD / PCDF will also be included as these areas could have been prone to contamination with ash or dust from the incineration process.

Dangerous Goods Store

4.3.4Outside the main hall on the west at the waterfront is the former dangerous goods store.  This was used to store chlorine.  The ground and floors are covered with reinforced concrete (Photo 22).  There was no visible contamination.

Dust and Grit Collection

4.3.4The major components of the dust and grit collection system was housed outside the main hall on the waterfront side.  At the completion of the combustion process the exhaust gasses were passed through a series of brick firebrick lined flues.  The ground was covered with reinforced concrete.  The ground in this area is raised about on metre above the waterfront level (Photo 27/28) and there appear to be areas where the remnants of the firebrick linings to the flues have been deposited.  Vegetation has since grown up around the debris left in this area (Photos 23 to 25).  There is no visible contamination, however since there was the potential for dust and ash to accumulate in this sea a cautious approach will be take and samples will be taken from two boreholes (B10 & B11) in this area.  These will roughly correspond to the areas which would formerly have been under the electrostatic precipitators or grit collectors.  The parameters for analysis will include HM and PCCD / PCDF will be included as these areas could have been prone to contamination with ash or dust from the incineration process.  TPH, PCB, PAH and BTEX will also be included to check for residual fuel oil, lubrication oil or electrical installations.

Dust Bunker

4.3.4The area is adjacent to the main hall.  The roof structure and metal bunker have been removed.  The remains of the outer concrete supporting structure can be seen in Photo 18 to the left of the chimney.  The ground has a heavy concrete covering and plant has been removed.  There is no obvious contamination however since a cautious approach will be take samples will be taken from a borehole (B12) in this area.  This will roughly correspond to the area, which would formerly have been under the bunker.  The parameters for analysis will include PAH, HM and PCDD / PCDF as these areas could have been prone to contamination with ash or dust from the incineration process.

Ash Hopper

4.3.4Outside the main hall on the east side was the ash hopper.  There was no obvious contamination, however since a cautious approach will be take samples will be taken from a borehole (B13) in this area.  This will roughly correspond to the area which would formerly have been under the hopper.  The parameters for analysis will include PAH, HM and PCDD / PCDF as these areas could have been prone to contamination with ash or dust from the incineration process.

Kennedy Town Abattoir

4.3.4The KTA is divided into three main blocks. These are the lairage block, the slaughterhouse block and the refrigeration block.  In addition there is the entrance unit and the boiler house block.

Entrance, Dispatch Bank & Parking

4.3.4The Dispatch Area and the parking area are concrete (Photo 32) and there is no surface contamination.

Lairage Entrance Unit and Transformer Chamber

4.3.4The area is adjacent to the lairage block at ground level (also referred to as the blood shop).  The indoor areas accommodate showers and offices.  The ground floor also houses the transformer rooms and the HEC transformer chamber (Photo 33).  There are no traces of contamination in this area, however there may be fissures in the concrete and contamination could have passed through the surface due to the outdoor location.  Therefore it is proposed to establish a borehole (B14) in this area.  The parameters for analysis will include TPH, PCB and BTEX in the ground around the transformer bays.

Manure Chute Refuse Collection Ground Floor

4.3.4The ramps leading to the manure and refuse collecting bay are concrete (Photos 34) and there is no obvious significant surface contamination.  The area to the west of the lairage and the area around is also concrete and there is no surface contamination.

Lairage and Reception Area

4.3.4The cattle and pig reception area and ramps leading from the quayside up to the covered lairage, are concrete (Photos 35 and 36).  These areas were regularly washed down in normal operations and there is no sign of surface contamination.

Water Treatment Plant

4.3.4The area is adjacent to the lairage block at ground level.  At ground floor level there is the water treatment plant (Photo 37 & 38).  There are no traces of contamination in this area.

Pump Room

4.3.4The area is also adjacent to the lairage block at ground level.  At ground floor level there is the pump room (Photo 39).  There are traces of surface contamination in this area, and there may be fissures in the concrete and contamination could have passed through the surface due to the location.  Therefore it is proposed to establish a borehole (B15) in this area.  The parameters for analysis will include TPH and BTEX.

Animal Carcass Incinerator

4.3.4The incinerators are housed adjacent to the boiler house chimney.  The incinerators areas are located on a concrete base with ceramic wall and floors.  The two incinerators (Photo 40 underexposed replace in final version) remain in standby mode but there is no heavy contamination in this area.  Local contamination and discoloration of the floors may be due to fuel leakage beneath the plant.  Therefore it is proposed to establish a borehole (B16) in this area.  The parameters for analysis will include TPH and BTEX.

Chimney

4.3.4The chimney is located between the incinerator and the fuel tanks.  The chimney is located on a concrete base (Photo 41) and there is no contamination in this area.

Boiler House

4.3.4The three boilers are housed adjacent to the chimney.  The boilers are located on a concrete base with ceramic walls and floors.  The boilers remain in standby mode and there is some heavy contamination in this area.  Local contamination and discoloration of the floors may be due to fuel leakage beneath the tanks (Photo 42).  Therefore it is proposed to establish a borehole (B17) in this area.  The parameters for analysis will include TPH and BTEX.

Diesel Fuel Tanks

4.3.4Two diesel fuel tanks are located adjacent to the boiler house. The tanks areas are located on a concrete base and the diesel tank area is bunded.  The two tanks (Photo 43) remain but there is no visible contamination (Photo 44).  However, since there are no records for inspection a cautious approach will be take and samples will be taken from a borehole (B18) in this area, adjacent to the fuel tank bund wall.  The parameters for analysis will include TPH and BTEX.

By-Product Plant

4.3.4Several calorifiers and blood boilers are housed on the ground floor of the slaughterhouse block.  The boilers are located on a concrete base with ceramic walls and floors.  The plant is redundant and there is no sign of heavy contamination in this area.  However local contamination and discoloration of the floors may be due to fuel leakage beneath the blood boilers etc. (Photo 45 & 46).  Therefore it is proposed to establish a borehole (B19) in this area.  The parameters for analysis will include TPH and BTEX.

Car Park Area

4.3.4The car parking area near the quayside are concrete (Photos 47).  These areas were regularly washed down in normal operations and there is no sign of surface contamination.  There is no major obvious contamination in this area, however since the aerial photographs appear to indicate some kind of open storage (possibly of coal) in this area (circa 1963) and since a cautious approach will be taken, samples will be taken from a borehole (B20) in this area.  The parameters for analysis will include HM, TPH and BTEX.

Meat Dispatch Area

4.3.4The area is founded on a concrete base with ceramic walls and floors. (Photo 48) remain in standby mode but there is no heavy contamination in this area. These areas were regularly washed down in normal operations and there is no sign of surface contamination.

New World First Bus Depot (NWFB)

4.3.4The NWFB is divided into three main areas.  These are the maintenance area, the fuel and lubrication areas and the office block.  As indicated in Photo 49, the depot compound work area is screeded with concrete to provide a suitable working surface and allow convenient vehicle access and manoeuvring in the maintenance and refuelling areas (Photo 50), and also to allow for controlled site drainage.

Fuel Tanks

4.3.4An above ground fuel tank, located near the entrance to the KTIP, is now used by the NWFB depot.  This area is bunded (Photo 2) and there is no obvious local contamination within or adjacent to the bunding (Photo 51).  The tanks area is located on a concrete base and concrete bunds were created around the fuel tank to control accidental leakage.  There is no major obvious contamination in this area, however since there are no records for inspection a cautious approach will be take and samples will be taken from two boreholes (B21 and B26) in this area.  B21 will be adjacent to the main fuel tank bund wall and B26 will be adjacent to the fuel dispensing machinery and subsurface pipes (Photo 21).  The parameters for analysis will include TPH and BTEX.

Lubrication Storage

4.3.4An above ground lubricating oil storage area is located near the entrance to the KTIP within the NWFB depot.  The lubrication oil storage area is located within a covered area on a concreted and bunded area at the south west of the site (Photo 52).  There is some contamination in this area and samples will be taken from a borehole (B22) in this area, adjacent to the lubrication store.  The parameters for analysis will include TPH and BTEX.

Battery and Chemical Waste Storage

4.3.4An above ground chemical waste storage area is located near the exit just within the NWFB depot (Photo 53).  This area is not bunded and there is no some obvious local contamination.  Since there is some contamination in this area, samples will be taken from a borehole (B23) adjacent to the battery store.  The parameters for analysis will include HM, TPH and BTEX.

Car Park

4.3.4The car park area is located adjacent between Sai See Street and the NWFB depot.   There is no storage in this area which is covered with concrete (Photo 54).  There is the possibility of some historic contamination in this area and samples will be taken from a borehole (B24) in this area.  The parameters for analysis will include HM, TPH and BTEX.

Cadogan Street Temporary Garden (CSTG)

Kennedy Town Abattoir/Incineration Plant (KTA/KTIP)

1.1.1As indicated from Photo 1 (Appendix A), the machine room of the KTIP work area is screeded with concrete.  The concrete plinths in the machine room show superficial hydrocarbon contamination.  The possibilities of asbestos containing materials (ACM) being present in the chinmeys and superstructures of the incinerator buildings and abattoir are being investigated and disposal procedure of any ACM will be covered the Asbestos Investigation Reports.  The existing above-ground fuel tank is located in the south-east corner of the compound (Photo 4).

1.1.1The lubrication oil storage area is located within a covered area on a concreted and bunded area of the site (Photo 9).  To the northern side of the site, the diesel storage tanks are located (Photo 13).  The concrete screed surface appeared to be superficially contaminated with diesel (Photo 14).

1.1.1As shown in Photo 16, the purpose built transformer room is situated on a concrete plinth and is located southern side of the compound.  To the northern side of the site, the plinth-mounted boilers as shown in Photos 15 and 19.

Bus Maintenance and Refuelling Depot (NWFB)

1.1.1As indicated in Photo 9, the depot compound work area is screeded with concrete to allow vehicle access to the maintenance and refuelling areas (Photo 21), and also to allow for controlled site drainage.

Other Areas

1.1.1The Cadogan Street Temporary Garden (CSTG) occupies the area of the former wholesale market which has recently been redeveloped and landscaped.  This area was formerly vacant open ground with a concrete covering.  To the north west side of the CSTG the Refuse Collection Point has recently been built.

Demolition of the KTCDA Compound

4.3.9          With respect to the current study, the principal opportunity for land contamination issues to occur during the demolition is related to excavation works.  Such areas include:

·               removal of the former incineration plant;

·               removal of the former abattoir compounds;

·               removal of the dangerous goods store;

·               removal of the existing bus maintenance depot;

·               removal of the flammable materials storage area; and

·               rRemoval of existing overground diesel and oil storage tanks and underground pipework or other substructures, such as inspection pits diesel and oil storage tanks at NWFB.

4.3.10      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, 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 in accordance with the requirements of the EIA Study Brief and investigation was conducted in line with this.  A dedicated Contamination Assessment Report and Remediation Action Plan was prepared.  The following sections summarise the detailed methodology and conclusions from the contamination assessment.

4.4              Methodology

4.4.1          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 presented in the CAR.

Criteria

4.3.10      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 (OSWER Directive 9200.4.26, Approach for Addressing Dioxin in Soil at CERCLA and RCRA Site).  This criterion has been used as the remediation target for residential sites in the USA (Appendix B).  The KTCDA Site is currently zoned as “G/IC”, and whereas the long term use of the area after demolition cannot be confirmed at present the above criterion is considered appropriate.

Sampling Protocol

4.3.11      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 considered 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.

4.3.12      The headroom underneath the existing buildings in the KTA was insufficient to allow free access to all areas at ground level.  However, the likely hotspots for contamination with hydrocarbons, such as near the fuel storage areas were covered and areas with fuel burning appliances were also sampled.  A large proportion of the abattoir site was covered however access was restricted in the CSTG and the Car Park. 

4.3.13      In order not to destroy large areas of the popular CSTG sitting out areas and to avoid interference with the operation of the Car Park sampling was restricted to one borehole in each of these areas and agreed with EPD.  Provisions have however been made to conduct additional sampling in these areas at a later stage, after demolition, in order to identify more precisely the extent of contamination and if necessary contaminated soil will be treated in line with the provisions for other contamination (see below).

4.3.14      The original CAP estimated about thirty 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 one borehole (TB29) position was adjusted.  One additional borehole (TB10A) was drilled based on the recommendations of the contaminated land specialist and site observations during the intrusive investigation.

4.3.15      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 and inspected on the spot by the contaminated land specialist.  Drilling continued to a minimum depth of 3.0m in accordance with the approved CAP or to a greater depth (to a maximum of approximately 5m) as instructed by the contaminated land specialist based on visual inspection.  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 subsequent groundwater sampling.

Soil Sampling

4.3.16      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 but sampling depths varied on a site-specific basis depending on the materials encountered.  In practice there was a heavy concrete cover of at least 300mm at most of the borehole locations and the top sample was taken at the level below the surface 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 at the time of drilling.  If contamination was clearly observed at certain depths, additional samples were taken from those depths.  Extra samples at deeper levels were also taken where suspected contamination was observed at the deepest nominal sample.

4.3.17      In practice the rock head was not encountered at any locations.  However, 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 contamination, especially at the deeper levels.  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

4.3.18      Groundwater accumulated in some boreholes rapidly after the completion of the drilling.  A bailer was used to remove water from the boreholes as necessary.  The boreholes were purged of (bailed out) three times the estimated standing water volumes prior to final natural recharge.  Samples were taken between 14th and 23rd June 2000.  It was found that repeat Site visits were required due to very slow recharge rates at some sampling locations.

4.3.19      Whereas groundwater was encountered at the final drill depth in most 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, dioxin and furan analyses.  This was the case in about one quarter of the boreholes including TB1, TB2, TB7, TB8, TB10, TB11, TB12, TB14, TB23, TB24 and TB27.

4.3.20      Samples were taken as far as possible from each borehole.  No free product was observed floating on the top of the groundwater but some samples contained suspended material and soil particles.  The laboratory was instructed to filter samples accordingly and conduct analysis on the filterable materials.

Sample Analysis

4.3.21      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);                                               (USEPA8290&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]

4.3.22      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 was 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. 

4.3.23      All samples from KTCDA were given the prefix T.  Soil samples from KTCDA were given the second letter S.  Groundwater samples from KTCDA were uniquely identified according to the borehole ID.  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 TSB7 M1.5.  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 twenty-one was designated as TSB21 X3.5.

4.3.24      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 land contamination.

4.4              Sampling Locations and Analysis of Results

4.4.1          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 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.


Table 4.1         Summary of Analytical Results – Soil Samples

Method 

USEPA 8015

USEPA 8260

USEPA 8270

EP066

USEPA 8290

USEPA 6020

EK026

EK055

EK071A

EA002

USEPA

Analysis Description

TPH

BTEX

PAH

PCB

PCDD / PCDF

METALS

Total Cyanide

Ammonia as N

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

mg/kg

 

%

Dutch B

1000

0.5 to 5.0

1 to 10

1

n/a

5 to 500

10

1000

200

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TSB1 S0.3

<B

<B

<B

 

 

>C (Cu, Pb, Zn)

>B<C (Cd)

<B

<B

<B

8.0

13.8

TSB1 M1.3

<B

<B

<B

 

 

>C (Cu, Pb, Zn)

>B<C (Cd, Hg)

<B

<B

<B

8.3

16.1

TSB1 X2.5

>B<C

<B

<B

 

 

>B<C (Cu, Pb, Zn)

<B

<B

<B

9.5

17.1

TSB1 B3.2

<B

<B

<B

 

 

>B<C (Pb)

<B

<B

<B

8.8

14.1

 

 

 

 

 

 

 

 

 

 

 

 

TSB2 S0.5

<B

<B

<B

<B

 

>C (Pb, Cu)

>B<C (As, Zn)

<B

<B

<B

9.0

18.1

TSB2 M1.5

<B

<B

<B

<B

 

<B

<B

<B

<B

8.4

13.5

TSB2 B3.0

<B

<B

<B

<B

 

<B

<B

<B

<B

8.4

13.8

 

 

 

 

 

 

 

 

 

 

 

 

TSB3 M2.5

<B

<B

<B

<B

 

>B<C (Cu, Pb, Zn, Hg)

<B

<B

<B

11.3

13.6

TSB3 B3.8

<B

<B

<B

<B

 

<B

<B

<B

<B

7.8

16.9

 

 

 

 

 

 

 

 

 

 

 

 

TSB4 S0.5

<B

<B

<B

 

<U

<B

<B

<B

<B

9.1

13.7

TSB4 M2.7

<B

<B

<B

 

<U

>B<C (Cu, Pb, Zn)

<B

<B

<B

9.5

15.1

TSB4 B3.9

<B

<B

<B

 

<U

>B<C (As, Cu, Pb, Zn)

<B

<B

<B

8.7

21.3

 

 

 

 

 

 

 

 

 

 

 

 

TSB5 S1.8

<B

<B

<B

 

<U

<B

<B

<B

<B

10.5

24.3

TSB5 M2.5

<B

<B

<B

 

<U

<B

<B

<B

<B

9.8

19.4

TSB5 B3.4

<B

<B

<B

 

<U

>B<C (Pb)

<B

<B

<B

9.4

18.6

 

 

 

 

 

 

 

 

 

 

 

 

TSB6 S0.6

<B

<B

<B

 

<U

<B

<B

<B

<B

9.1

17.1

TSB6 M2.2

<B

<B

<B

 

<U

<B

<B

<B

<B

8.7

13.5

TSB6 B3.3

<B

<B

<B

 

<U

<B

<B

<B

<B

9.2

14.6

 

 

 

 

 

 

 

 

 

 

 

 

TSB7 S1.5

<B

<B

<B

<B

<U

<B

<B

<B

<B

8.6

24.0

TSB7 M2.7

<B

<B

<B

<B

<U

<B

<B

<B

<B

9.2

18.7

TSB7 B3.3

<B

<B

<B

<B

<U

<B

<B

<B

<B

8.8

17.0

 

 

 

 

 

 

 

 

 

 

 

 

TSB8 S1.1

<B

<B

<B

 

<U

<B

<B

<B

<B

9.7

13.6

TSB8 M2.6

<B

<B

<B

 

<U

<B

<B

<B

<B

8.5

13.6

TSB8 B3.1

<B

<B

>B<C (benzopyrene)

 

<U

<B

<B

<B

<B

8.9

13.8

 

 

 

 

 

 

 

 

 

 

 

 

TSB9 S1.0

<B

<B

<B

 

<U

>B<C (Pb)

<B

<B

<B

9.7

17.0

TSB9 M2.4

<B

<B

<B

 

<U

<B

<B

<B

<B

8.3

17.7

TSB9 B3.3

<B

<B

<B

 

<U

<B

<B

<B

<B

10.8

14.7

 

 

 

 

 

 

 

 

 

 

 

 

TSB10 S0.4

>B <C

<B

<B

 

<U

>C (Pb)

>B<C (Cd, Cu, Zn)

<B

<B

<B

7.3

31.6

TSB10 M1.2

<B

<B

<B

 

>U

>C (As, Cd, Cu, Pb, Zn)

<B

<B

<B

8.3

35.2

TSB10 B1.8

<B

<B

<B

 

<U

<B

<B

<B

<B

10.5

29.6

 

 

 

 

 

 

 

 

 

 

 

 

TSB10A M2.6

<B

<B

<B

 

<U

<B

<B

<B

<B

10.4

13.2

TSB10A B3.9

<B

<B

<B

 

<U

<B

<B

<B

<B

9.0

14.9

 

 

 

 

 

 

 

 

 

 

 

 

TSB11 S0.5

<B

<B

<B

 

>U

>C (Pb)

>B<C (Cd, Cu, Zn)

<B

<B

<B

11.0

21.3

TSB11 M2.4

<B

<B

<B

 

<U

<B

<B

<B

<B

9.0

18.4

TSB11 B3.8

<B

<B

<B

 

<U

>B<C (Pb)

<B

<B

<B

9.2

20.3

 

 

 

 

 

 

 

 

 

 

 

 

TSB12 S0.5

<B

<B

<B

 

<U

>B<C (Cd, Cu, Pb, Zn)

<B

<B

<B

9.0

12.9

TSB12 M2.5

<B

<B

<B

 

<U

<B

<B

<B

<B

9.0

11.4

TSB12 B3.5

<B

<B

<B

 

<U

<B

<B

<B

<B

8.5

15.3

 

 

 

 

 

 

 

 

 

 

 

 

TSB13 S0.5

<B

<B

<B

 

<U

<B

<B

<B

<B

9.1

7.8

TSB13 M1.5

<B

<B

<B

 

<U

<B

<B

<B

<B

9.5

15.9

TSB13 B3.0

<B

<B

<B

 

<U

>B<C (Pb, Zn, Hg)

<B

<B

<B

8.4

24.5

 

 

 

 

 

 

 

 

 

 

 

 

TSB14 S0.4

<B

<B

<B

<B

 

<B

<B

<B

<B

8.6

10.3

TSB14 M2.5

<B

<B

<B

<B

 

<B

<B

<B

<B

8.3

12.0

TSB14 B3.5

<B

<B

<B

<B

 

<B

<B

<B

<B

8.3

18.8

 

 

 

 

 

 

 

 

 

 

 

 

TSB15 S0.4

<B

<B

>B<C (benzopyrene)

<B

 

>C (Cu, Pb, Zn)

>B<C (As, Hg)

<B

<B

<B

8.8

12.9

TSB15 M2.3

<B

<B

<B

<B

 

<B

<B

<B

<B

8.3

23.6

TSB15 B3.5

<B

<B

<B

<B

 

<B

<B

<B

<B

8.3

12.9

 

 

 

 

 

 

 

 

 

 

 

 

TSB16 S0.8

<B

<B

<B

 

 

>B<C (Cu, Pb, Zn)

<B

<B

<B

7.8

14.0

TSB16 M2.3

<B

<B

<B

 

 

<B

<B

<B

<B

9.0

17.2

TSB16 B3.6

<B

<B

<B

 

 

>B<C (Pb)

<B

<B

<B

8.4

20.3

 

 

 

 

 

 

 

 

 

 

 

 

TSB17 S0.4

<B

<B

<B

 

 

>B<C (Hg)

<B

<B

<B

10.4

15.3

TSB17 M2.3

<B

<B

<B

 

 

>B<C (Pb)

<B

<B

<B

8.5

26.3

TSB17 B3.0

<B

<B

<B

 

 

<B

<B

<B

<B

8.7

9.1

 

 

 

 

 

 

 

 

 

 

 

 

TSB18 S1.0

<B

<B

<B

<B

 

>B<C (Pb)

<B

<B

<B

8.6

18.6

TSB18 M2.4

<B

<B

<B

<B

 

<B

<B

<B

<B

9.2

13.2

TSB18 B3.8

<B

<B

<B

<B

 

<B

<B

<B

<B

9.3

21.7

 

 

 

 

 

 

 

 

 

 

 

 

TSB19 S0.6

<B

<B

<B

 

 

>B<C (Pb)

<B

<B

<B

7.5

12.2

TSB19 M2.3

<B

<B

<B

 

 

>B<C (Pb, Hg)

<B

<B

<B

7.6

21.6

TSB19 B3.5

<B

<B

<B

 

 

>B<C (Hg)

<B

<B

<B

7.8

18.8

 

 

 

 

 

 

 

 

 

 

 

 

TSB20 S0.3

<B

<B

>B<C

(pyrene, benzopyrene)

<B

 

>C (Pb)

>B<C (As, Cd, Cu, Zn, Hg)

<B

<B

<B

9.4

26.6

TSB20 M1.5

>C

<B

>C (pyrene, benzopyrene)

>B<C (fluoranthene)

<B

 

>B<C (Cu)

<B

<B

<B

8.3

28.6

TSB20 B3.2

<B

<B

<B

<B

 

<B

<B

<B

<B

8.6

10.9

 

 

 

 

 

 

 

 

 

 

 

 

TSB21 S0.5

<B

<B

<B

 

 

>C (Cu, Pb, Zn)

>B<C (Hg)

<B

<B

<B

8.8

14.8

TSB21 M2.4

<B

<B

<B

 

 

<B

<B

<B

<B

8.6

8.1

TSB21 X3.5

>B<C

<B

<B

 

 

<B

<B

<B

<B

7.7

12.3

TSB21 B4.9

<B

<B

<B

 

 

>B<C (Pb, Hg)

<B

<B

<B

8.5

12.9

 

 

 

 

 

 

 

 

 

 

 

 

TSB22 S0.5

<B

<B

<B

 

 

>B<C (Pb)

<B

<B

<B

9.1

14.4

TSB22 M1.8

<B

<B

<B

 

 

<B

<B

<B

<B

8.6

11.1

TSB22 B2.9

<B

<B

<B

 

 

<B

<B

<B

<B

8.9

15.3

 

 

 

 

 

 

 

 

 

 

 

 

TSB23 S0.5

<B

<B

<B

 

 

>B<C (Pb)

<B

<B

<B

8.2

9.5

TSB23 M1.9

<B

<B

<B

 

 

<B

<B

<B

<B

10.9

10.3

TSB23 B3.4

<B

<B

<B

 

 

>B<C (Pb)

<B

<B

<B

8.8

17.1

 

 

 

 

 

 

 

 

 

 

 

 

TSB24 S1.2

<B

<B

<B

<B

<U

>B<C (Pb, Hg)

<B

<B

<B

7.9

6.9

TSB24 M2.0

<B

<B

<B

<B

<U

>B<C (Pb, Hg)

<B

<B

<B

7.9

15.9

TSB24 X3.0

<B

<B

<B

<B

<U

>B<C (Pb)

<B

<B

<B

8.4

18.8

TSB24 B4.0

<B

<B

<B

<B

<U

>B<C (Cu, Pb)

<B

<B

<B

8.4

17.7

 

 

 

 

 

 

 

 

 

 

 

 

TSB25 S0.9

<B

<B

<B

<B

<U

<B

<B

<B

<B

8.1

14.4

TSB25 M1.6

<B

<B

>B<C (benzopyrene)

<B

<U

<B

<B

<B

<B

10.0

19.2

TSB25 X2.9

<B

<B

<B

<B

<U

>B<C (Pb)

<B

<B

<B

8.1

13.8

TSB25 B3.9

<B

<B

<B

<B

<U

>B<C (Pb, Hg)

<B

<B

<B

8.4

12.4

 

 

 

 

 

 

 

 

 

 

 

 

TSB26 S0.8

>B<C

<B

<B

 

 

>B<C (Pb)

<B

<B

<B

9.2

15.2

TSB26 M1.8

<B

<B

<B

 

 

<B

<B

<B

<B

9.9

13.3

TSB26 X2.7

>C

<B

<B

 

 

>B<C (Cu, Pb, Zn, Hg)

<B

<B

<B

9.0

12.7

TSB26 B3.4

<B

<B

<B

 

 

<B

<B

<B

<B

8.6

12.3

 

 

 

 

 

 

 

 

 

 

 

 

TSB27 S0.5

<B

<B

<B

 

 

<B

<B

<B

<B

8.3

13.6

TSB27 M2.0

<B

<B

<B

 

 

<B

<B

<B

<B

8.1

13.8

TSB27 B3.4

<B

<B

>B<C (benzopyrene)

 

 

>C (Pb)

>B<C (Cu)

<B

<B

<B

8.3

18.4

 

 

 

 

 

 

 

 

 

 

 

 

TSB28 S0.4

<B

<B

<B

 

<U

>C (Pb)

>B<C (Cd, Cu, Zn)

<B

<B

<B

9.5

18.3

TSB28 M2.1

<B

<B

<B

 

<U

<B

<B

<B

<B

9.6

16.8

TSB28 B3.6

<B

<B

<B

 

<U

>C (Pb, Cu)

>B<C (As, Zn)

<B

<B

<B

10.7

16.9

 

 

 

 

 

 

 

 

 

 

 

 

TSB29 S0.5

<B

<B

<B

<B

 

>B<C (Cu, Pb, Zn)

<B

<B

<B

8.0

21.2

TSB29 X1.0

<B

<B

<B

<B

 

<B

<B

<B

<B

8.1

12.1

TSB29 M1.3

<B

<B

<B

<B

 

>B<C (Cu, Zn, Hg)

<B

<B

<B

8.3

17.7

TSB29 X2.0

<B

<B

<B

<B

 

>C (Pb)

>B<C (Zn)

<B

<B

<B

9.0

20.3

TSB29 B3.0

<B

<B

<B

<B

 

>C (Pb)

<B

<B

<B

9.2

22.6

 

 

 

 

 

 

 

 

 

 

 

 

TSB30 S0.6

<B

<B

<B

 

<U

>B<C (Pb)

<B

<B

<B

10.1

9.3

TSB30 M2.4

<B

<B

<B

 

<U

<B

<B

<B

<B

7.6

15.4

TSB30 B3.5

<B

<B

<B

 

<U

<B

<B

<B

<B

8.7

23.8

N.B.         B and C refer to Dutch B and C criteria. U refers to USEPA criteria.

 


Table 4.2         Summary of Analytical Results – Groundwater Samples

Method 

USEPA 8015

USEPA 8260

USEPA 8270

EP066

USEPA 8290

USEPA 6020

EK026

EK071A

EA002

Analysis Description

TPH

BTEX

PAH

PCB

PCDD / PCDF

METALS

Total Cyanide

Reactive Phosphorus as P

pH Value @ 25'C

Unit

ug/l

ug/l

ug/l

ug/l

 

ug/l

ug/l

ug/l

 

Dutch B

200

30

10

0.2

 

50

50

200

 

TSB1

IS

IS

IS

-

-

IS

IS

IS

IS

TSB2

IS

IS

IS

IS

-

IS

IS

IS

IS

TSB3

>B<C

<B

>B<C (Phenanthrene)

<B

-

<B

<B

<B

8.2

TSB4

>C

<B

<B

-

IS

IS

IS

IS

IS

TSB5

<B

 

<B

-

<U

>C (Cd, Cu, Pb, Zn)

<B

IS

IS

TSB6

IS

<B

IS

-

IS

IS

IS

IS

IS

TSB7

IS

IS

IS

-

IS

IS

IS

IS

IS

TSB8

IS

IS

IS

-

<U

IS

IS

IS

IS

TSB9

IS

<B

IS

-

<U

IS

<B

IS

IS

TSB10

IS

IS

IS

-

<U

IS

IS

IS

IS

TSB10A

IS

IS

IS

-

<U

IS

IS

IS

IS

TSB11

IS

IS

IS

-

<U

IS

IS

IS

IS

TSB12

IS

IS

IS

-

IS

IS

IS

IS

IS

TSB13

<B

<B

<B

-

<U

>C(Cd) >B(Cu,Pb)

<B

<B

7.8

TSB14

IS

IS

IS

IS

-

IS

IS

IS

IS

TSB15

>C

<B

>B (various)

>B<C

-

<B

<B

<B

9.8

TSB16

>B<C

<B

<B

-

<U

>B (As)

<B

<B

7.3

TSB17

>B<C

<B

<B

-

-

>C (Cu, Pb, Zn)

<B

<B

7.2

TSB18

>B<C

<B

<B

<B

-

>C (Cd, Cu, Pb, Zn)

<B

<B

7.5

TSB19

>B<C

<B

<B

-

-

>C (Cu, Pb, Zn)

<B

<B

7.3

TSB20

<B

<B

>C

<B

-

<B

<B

<B

7.5

TSB21

>C

IS

>B<C (Pyrene)

-

-

>C (Cd, Cu, Pb, Zn)

<B

<B

10.7

TSB22

>C

<B

>B<C (Fluoranthene, Pyrene)

-

-

IS

IS

IS

IS

TSB23

IS

IS

IS

-

-

IS

IS

IS

IS

TSB24

IS

IS

IS

IS

IS

IS

IS

IS

IS

TSB25

>B<C

<B

<B

<B

<U

<B

<B

>B

7.2

TSB26

IS

IS

IS

-

-

IS

IS

IS

IS

TSB27

IS

IS

IS

-

-

IS

IS

IS

IS

TSB28

IS

<B

IS

-

<U

>C (Cd, Cu, Pb, Zn)

<B

<B

8.6

TSB29

<B

<B

<B

-

-

<B

<B

<B

7.6

TSB30

IS

<B

>B<C

(Fluoranthene, Pyrene, Benzopyrene)

-

<U

>C (Cd ),>B (Zn)

<B

<B

7.6

Note: IS = insufficient sample  B and C refer to Dutch B and C criteria, U refers to USEPA criteria (Appendix B).


4.5              Contamination Assessment

Local Contamination Levels

4.5.1          The presence of soil contaminants does not necessarily imply that there are any implications for the demolition procedures or public health.  The possibilities for contact with ground contaminants during the demolition of KTCDA are relatively low, provided appropriate precautions are implemented.  This is because ground excavations will not be necessary.  Therefore in the context of the demolition activities associated with the current EIA study, worker contact with ground contaminants will not take place.  However the possibilities for contact with ground contaminants during the site clean up cannot be ruled out and appropriate precautions should be implemented, as recommended later in this section.  It is recommended that the planned remedial actions for underground contaminants take place after the civil demolition.  The purpose of this section of the EIA Report is to allow the consultants to draw attention to those samples where contamination has been identified and assess if and when remedial action is required.

Inorganic Parameters

4.5.2          The inorganic contaminants sulphate, ammonia, phosphorous and cyanide were measured.  Cyanide was not recorded above the Dutch B criterion at the KTCDA site at any location.  No clean up is considered necessary with respect to inorganic parameters at any area of the site.

Heavy Metals

4.5.3          Heavy metal (HM) levels were recorded above the Dutch B criteria and require clean-up within the underlying ground at TB1, TB2, TB3, TB4, TB5, TB9, TB11, TB12, TB13, TB15, TB16, TB17, TB18, TB19, TB20, TB21, TB22, TB23, TB24, TB25, TB26, TB27, TB28, TB29, and TB30.  At TB10 (between the chimneys) the surface deposits also contain HM.  The most common elements identified were Pb, Cu, Zn and Cd.  As and Hg were also present in some samples above the Dutch B criteria.  In many incidences exceedance of the Dutch C level were recorded in the surface samples, but not always.  There is no consistent pattern to the location of the contamination and in many cases exceedances at one sampling depth are not repeated at different depths within the same borehole.  This suggests that the heavy metals remain localised and immobile within the ground.  Remediation is necessary to comply with government policy and a Remediation Action Plan has been prepared.

4.5.4          In addition heavy metal concentrations were recorded above Dutch C criteria at three of the boreholes drilled through the surface rubble located between the KTIP chimney stacks (Figure 4.1 refers).

Total Petroleum Hydrocarbons

4.5.5          TPH has been recorded as exceeding Dutch B criteria in underlying ground in four boreholes (TB1, TB20, TB21 and TB26).  Where high TPH levels were recorded at TB1, TB21 and TB26 this is believed to be due to diesel fuel leakage.  Where high TPH levels were encountered in exceedance of the Dutch C criterion at TB20 there was no evidence of diesel usage but coal particles were identified in the contaminated layers. TPH was also recorded as exceeding the Dutch B criterion for the surface level sample at TB10 and in groundwater samples at TB3, TB4, TB15, TB16, TB17, TB18, TB19, TB20, TB21, TB22 and TB25.  However, this material is surface rubble located above the hardstanding.  With respect to the current study, it is considered that underground contamination would not be disturbed as a function of demolition of structures.  However, remediation is necessary to comply with Government policy and to allow unconstrained re-use of the site following the completion of demolition.

Polyaromatic Hydrocarbons (Polynuclear Aromatics, PAH)

4.5.6          A selection of 15 PAH including those on the Dutch list were analysed in all samples.   The limit of detection was below the Dutch B criterion for such contaminants.  PAH was recorded above the Dutch B criteria at five of the thirty-one borehole locations (TSB8, TB15, TB20, TB25 and TSB27).  It is noted that the vertical distribution of such contaminated was limited for PAHs.  Therefore, such contamination may be considered as relatively immobile.  In addition, two parameters exceeded the Dutch C criteria at TB20 and were possibly due to a layer coal dust encountered at a specific depth.  This material could result from the use of the area as a coal yard.  PAH was also recorded as exceeding the Dutch B criterion in groundwater samples at TB3, TB15, TB20, TB21, TB22 and TB30.  Remediation of such contamination is necessary to comply with government policy.

Benzene , Toluene, Ethylbenzene, Xylene (BTEX)

4.5.7          BTEX included on the Dutch list were analysed in all samples.   No exceedance of the Dutch B criteria was recorded at any of the borehole locations. 

Polychlorinated Biphenyl (PCB)

4.5.8          Total PCB was analysed in selected samples.   The limit of detection was below the Dutch B criterion.  PCB was not recorded in exceedance of the Dutch B criterion in any ground material samples.  PCB was not recorded above the Dutch B criterion in any of the samples taken from the surface rubble material located between the KTIP chimneys.  PCB was recorded as exceeding the Dutch B criterion in groundwater samples at TB15.  Remediation plans have included provisions for such contamination.

pH

4.5.9          The range of pH values encountered was from pH 11.3 to pH 7.3.  Given the range of soil types sandy to clay and fill materials encountered such a range of pH is not exceptional and not significant in terms of contamination.

Dioxins and Furans (PCDD & PCDF)

4.5.10      A selection of 25 PCDD and PCDF congeners were analysed in selected samples.  The USA criterion for such contaminants was adopted for this study.  PCDD and PCDF congeners were not detected in any of the soil samples across the entire KTCDA site at above the USA criterion.

4.5.11      Significant concentrations of PCDD and PCDF congeners were recorded at the surface rubble / ash located between the two KTIP chimney stacks (Figure 4.1).  Samples TB10 and TB11 show evidence of contamination in the rubble found above the hardstanding, but not in the soils below the hardstanding.  Samples TB10 has PCDD and PCDF up to 6.8ppb TEQ.  TB11 shows evidence of PCDD and PCDF contamination up to 1.3ppb TEQ.  The presence of PCDD and PCDF in some of the rubble could be due to ash or other materials originating from inside the flue ducts which originally led to the chimneys or ash from the chimney stacks themselves.

4.5.12      The location and amounts of PCCD and PCDF contaminated rubble / 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 soil samples.  Remedial action will be required to clean up these rubble materials prior to the demolition as PCDD/PCDF were above the USEPA criterion in some of the samples.  Special precautions will be required which are dealt with under the RAP section of this report.

4.5.13      The material that is contaminated is rubble deposited on top of the original hardstanding.  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.  The approximate extent of surface material requiring removal is indicated in Figure 4.2.  This material must be removed by an appropriately qualified specialist contractor and must collected, transported and deposited at landfill in accordance with criteria and conditions specified by EPD.

Overall Contamination Levels

Soil

4.5.14      Many borehole locations have recorded soil contamination above the Dutch B criteria for HM, TPH or PAH.  Most samples have indicated that where the quantities of soil contaminants have been detected above the “Dutch B” criteria, concentrations are generally below the “Dutch C” criteria.  With respect to ground conditions below the current concrete hardstanding, the site cannot be described as uncontaminated but contamination is not consistent throughout all soil horizons and depths.

4.5.15      Based on chemical analyses soil contamination with HM (commonly Pb, Cu, Zn, Cd, occasionally As and Hg) will require remedial action at TB1, TB2, TB3, TB4, TB5, TB9, TB10, TB11, TB12, TB13, TB15, TB16, TB17, TB18, TB19, TB20, TB21, TB22, TB23, TB24, TB25, TB26, TB27, TB28, TB29, and TB30. Additionally alternative methods will be required to deal with organic contamination (TPH and PAH) at TB1, TB8, TB10, TB15, TB20, TB21, TB25, TB26 and TB27.  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.

Rubble Deposits between Chimneys (KTIP)

4.5.16      PCDD/PCDF were above the USEPA criterion in TB10 and TB11 in the rubble material above the hardstanding in the area between the two chimney stacks of KTIP.  PCDD/PCDF were below the USEPA criterion soils below the hardstanding.  Remedial action will be required to clean up the rubble 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 rubble materials between the chimneys be cleaned up.

Groundwater

4.5.17      As groundwater is not utilised as a potable resource in Hong Kong the “Dutch B” criteria are not generally applicable.  Remedial action is however required for the soils. .  In any locations where water from underground is contaminated, remediation on the soil should also stabilise and immobilise any possible leachate entering the groundwater.  The possibility of contamination in groundwater cannot be ruled out and the contractor will be required to make provisions to treat surplus groundwater to reduce chemical concentrations in order to comply with the standards for effluents discharged into the inshore waters of Victoria Harbour WCZ.

Requirement for Remediation

4.5.18      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 at most areas of investigation across the KTCDA site.  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 KTCDA are relatively low, provided appropriate precautions are implemented.  This is because ground excavations will not be necessary.  However, soil remediation is necessary to comply with government policy.  Contaminants present in rubble between the chimneys at KTIP must be cleaned up under controlled conditions prior to the demolition.   The potential for odour impacts is also considered negligible, since no evidence for odorous ground conditions was detected at the time of ground investigations.

4.5.19      The KTCDA site is currently zoned as “G/IC” (long term use of the area after demolition has yet to be confirmed).  Remediation of the site will be necessary to comply with government policy, prior to the next use of the site.

4.6              Remediation Action Plan

Extent of Contamination

4.6.1          Where present the concentrations of contaminants encountered do not have implications for the demolition of the KTCDA as no excavation is necessary for the demolition.  However, it is understood that remediation will be required in accordance with government policy.

4.6.2          Clean up of several areas is required to remove such contaminants as heavy metals and organic compounds (TPH and PAH) identified in the contamination assessment.  Where contamination above the appropriate Dutch B level has been identified, remedial action should take place.  Reassurance / confirmatory sampling should also be undertaken to confirm that all material with contaminants above the Dutch B levels has been cleaned up.  Analysis will be required to confirm that at the periphery of the extracted material, parameters are at acceptable levels.  It is recommended that this process is concurrent with the excavation of soil for remedial treatment and after the demolition has been completed.  This will then allow the confirmation of the final extent of all material that will require remediation.

4.6.3          For each of the locations where contamination has been identified under the current study soil material should be excavated to a point deeper than the greatest depth where contamination was identified, and to a 5m square from the original sampling point, for on-site remedial treatment.  Confirmatory soil sampling should be undertaken N, S, E and W of the excavated hole, and at the base of the hole to confirm that all contaminated material has been removed for treatment.  If confirmatory soil analysis indicates concentrations above the Dutch B levels, further material must be excavated and analysis made at the periphery of the excavation to confirm that parameters are at acceptable levels.

4.6.4          The locations requiring clean up based on the information gathered so far is summarised in Table 4.3 which also indicates where confirmatory sampling is warranted.  At this time it is not possible to confirm the exact total amounts of soil material requiring treatment.  A broad-brush estimate of the amount of material for treatment within 5m of the boreholes in the contaminated horizons has been made (Table 4.3).  This estimate is based on an assumption that further reassurance/confirmatory sampling not identifying any additional contaminated areas.

4.6.5          It has been mentioned earlier that in order not to interfere with the CSTG and the Car Park sampling was restricted in these areas.  Additional sampling in these areas will therefore be required and a supplementary Contamination Assessment Plan shall be agreed with EPD for implementation after the demolition.  Procedures shall follow the guidance given in Practice Note for Professional Persons PN 3/94.  Additional sampling points, particularly in the CSTG and Car Park shall be analysed in order to identify more precisely the extent of contamination.  If necessary additional contaminated soil will be treated in line with the provisions for other contamination.

4.6.6          Whereas it is not possible to make a meaningful allowance for any additional contaminated material in advance of the reassurance/confirmatory sampling and analyses it is reasonable to expect at least some of the reassurance/confirmatory sampling to indicate that additional areas will require treatment.  According to the quantity of contaminated material estimated for treatment from each borehole location, the total quantity of contaminated soil should be about 6055m3 with about 4635m3 (say 75%) of the total volume estimated to require treatment on site by immobilisation and 1,420m3, to be transferred to landfill.  In the event that say 40% of the reassurance/confirmatory sampling indicated that additional areas required treatment about 8500m3 contaminated soil would arise with about 6400m3 of the total volume requiring treatment on site by immobilisation and 2,100m3, to be transferred to landfill.  Clearly these figures are very broad estimates and require confirmation at a later stage.  However even if the quantities do require revision this would not affect the reliability of the handling, treatment or disposal methods options as the quantities expected would be likely to be of the same order of magnitude.

Remediation Options for Soils

Heavy Metal Contamination

4.6.7          Excavation and landfilling is often seen as the most convenient method for treatment of contaminated material, 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.  In-situ immobilisation or stabilisation is to be applied as a remediation methodology for the land contaminated with heavy metals (ProPECC PN3/94, Appendix III).

4.6.8          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 and returning the extracted material to the ground and compacting.  Treated material should be returned in the form of small blocks.  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.

4.6.9          Remediation for heavy metals alone, by immobilisation, will be required at those locations where HM exceeded the Dutch B levels and where action is indicated in Table 4.3. The immobilisation process will involve the excavation of the covering concrete and any covering materials that are not contaminated (as shown by previous sampling).  Contaminated materials at specific horizons within a 5m of the borehole between specified depths will then be removed.  It is required that reassurance sampling be carried out at the extremities of the excavated hole to test for any surplus contamination (Table 4.3 refers).  Five samples would generally be taken at positions N, S, E, W and at the base of excavated hole.  Soil samples would be analysed for the contaminating metals identified at that location.  If samples contain contaminants above the Dutch B levels, further excavation is required, either at the sides or at the bottom as appropriate, until uncontaminated material is identified.

4.6.10      Contaminated materials will be removed, stockpiled separately from the uncontaminated materials and mixed with the appropriate amount of cement for immobilisation.  Initially pilot TCLP tests will be carried out to determine the appropriate mix of cement to soil.  The mixture will be cast in small blocks and the blocks placed / stacked back in the holes.  Uncontaminated material can then be used to fill around the blocks and compacted to level the surface.

Other Contaminants

4.6.11      Whereas some references indicate that the above 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 and performance guaranteed.  In this case the quantities of contaminated soil caused by agents other than heavy metals is small (a few hundred cubic metres) and disposal at landfill following pre-treatment, where required, is the recommended option in such cases (Tables 4.1 & 4.3 refer).

4.6.12      Prior to landfill disposal, the leaching characteristics of the untreated materials shall be determined by toxicity characteristic leachate procedures (TCLP, ASTMS Method 1311).  If the untreated 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-à-vis the treatments to be applied at each location will be the same as for the heavy metals.

4.6.13      Reassurance sampling will also take place for hydrocarbon contaminated locations and the provisions are summarised in Table 4.3.  Table 4.3 indicates where remedial action will be required, where 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 at least 0.3 to 0.5 metre depth is allowed above and below the shallowest and deepest contamination detected.

4.6.14      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).

4.6.15      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.


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 (m3, #)

Reassurance / Confirmatory Sampling

Sampling Strategy

TB1

Yes

Concrete down to 0.3m depth

Immediately below concrete 0.3m to 4.0m

Immobilisation for 0.3m to 2.0m and 3.0m to 4.0m*

TCLP test followed by removal of 2.0m to 3.0m to landfill.  Immobilisation if TCLP tests exceed criteria **.

100 to be removed to landfill

+

270 @

Yes, determine extent of HM (Cd, Cu, Pb, Zn and Hg) and TPH contamination at edge and base of excavated hole.*

5 samples 5m N, S, E ,W and base of borehole.

TB2

Yes

Concrete down to 0.5m depth

Immediately below concrete 0.5m to 1.5m

Immobilisation*

100

Yes, determine extent of HM (As, Cu, Pb and Zn) contamination at edge and base of excavated hole.*

5 samples 5m N, S, E ,W and base of borehole.

TB3

Yes

Concrete down to 2.5m depth

2.5m to 3.5m

Immobilisation *

100

Yes, determine extent of HM (Cu, Pb, Zn and Hg) contamination at edge and base of excavated hole.*

5 samples 5m N, S, E & W and base of borehole.

TB4

Yes

Down to 2.2m depth

2.2m to 4.2m

Immobilisation *

200

Yes, determine extent of HM (As, Cu, Pb and Zn) contamination at edge and base of excavated hole.*

4 samples 5 m N, S, E & W of borehole plus one at base of hole layer

TB5

Yes

Concrete down to 1.8m.  Down to 2.5m depth

2.5m to 4.0m

Immobilisation*

200

Yes, determine extent of HM (Pb) contamination at edge and base of excavated hole.*

4 samples 5 m N, S, E & W of borehole plus one at base of hole layer

TB6

No

N/A

N/A

N/A

0

N/A

N/A

TB7

No

N/A

N/A

N/A

0

N/A

N/A

TB8

Yes

Concrete down to 1m. Down to 2.5m

2.5m to 3.5m

TCLP test followed by removal of 2.5m to 3.5m to landfill.  Immobilisation if TCLP tests exceed criteria **.

100 to be removed to landfill @

Yes, determine extent of PAH contamination at edge and base of excavated hole.*

5 samples 5m N, S, E ,W and base of borehole.

TB9

Yes

Concrete down to 1.0m depth

1.0m to 2.0m

Immobilisation*

100

Yes, determine extent of HM (Pb) contamination at edge and base of excavated hole.*

4 samples 5m N, S, E & W and base of borehole.

TB10

Yes

Surface rubble/ash and brick material (not soil) about 1.5m depth.

1.5 m

Clear Waste to landfill.  Waste to be treated and tested to meet EPD disposal criteria. 

Up to, say, 300m3 (surface material, not for in-situ treatment) @

Yes, determine extent of HM (As, Cd, Cu, Pb, Zn) TPH and PCDD/PCDF contamination under surface contaminated materials.*

4 samples 5 m N, S, E & W of borehole plus one at bore hole

TB10a

No

N/A

N/A

N/A

0

N/A

N/A

TB11

Yes

Down to 1.5m depth

1.5 m

Clear Waste to landfill.  Waste to be treated and tested to meet EPD disposal criteria. 

(See TB10, for materials not for in-situ treatment)

Yes, determine extent of HM (Cd, Cu, Pb, and Zn) and PCDD/PCDF contamination under surface contaminated materials.*

5 samples 5m N, S, E & W of borehole plus one at borehole

TB11

Yes

Below hardstanding surface (soil materials)

1.5 to 4.0m

Immobilisation* 

200 (for in-situ treatment)

Yes, to determine extent of HM (Pb) contamination at edge and base of excavated hole.

5 samples 5m N, S, E & W of borehole plus one at base of hole layer

TB12

Yes

Concrete down to 0.5m

0.5 to 1.5m

Immobilisation*

100

Yes, determine extent of HM (Cd, Cu, Pb and Zn) contamination at edge and base of excavated hole.*

5 samples 5m N, S, E & W and base of borehole.

TB13

Yes

Down to 2.5m

2.5m to 3.5m

Immobilisation*

100

Yes, determine extent of HM (Pb, Zn, Hg) contamination at edge and base of excavated hole.*

5 samples 5m N, S, E & W and base of borehole.

TB14

No

N/A

N/A

N/A

0

N/A

N/A

TB15

Yes

Concrete down to 0.4m

0.4 to 2.4m

TCLP test followed by removal of 0.4m to 2.4m to landfill.  Immobilisation if TCLP tests exceed criteria **.

200 to be removed to landfill @

Yes, determine extent of HM (As, Cu, Pb, Hg and Zn) and PAH contamination at edge and base of excavated hole.*

5 samples 5m N, S, E & W and base of borehole.

TB16

Yes

Concrete down to 0.8m

0.8 to 4.3m

Immobilisation *

350

Yes, determine extent of HM (Cu, Pb and Zn) contamination at edge and base of excavated hole.*

5 samples 5m N, S, E & W and base of borehole.

TB17

Yes

Concrete down to 0.4m

0.4 to 2.4m

Immobilisation *

200

Yes, determine extent of HM (Pb and Hg) contamination at edge and base of excavated hole.*

5 samples 5m N, S, E & W and base of borehole.

TB18

Yes

Concrete down to 1.0m

1.0m to 2.0m

Immobilisation *

100

Yes, determine extent of HM (Pb) contamination at edge and base of excavated hole.*

5 samples 5m N, S, E & W and base of borehole.

TB19

Yes

Concrete down to 0.6m

0.6m to 4.0m

Immobilisation *

375

Yes, determine extent of HM (Pb and Hg) contamination at edge and base of excavated hole.*

5 samples 5m N, S, E & W and base of borehole.

TB20

Yes

Concrete down to 0.3m

0.3m to 2.3m

TCLP test followed by removal of 0.3m to 2.3m to landfill.  Immobilisation if TCLP tests exceed criteria **.

200 to be removed to landfill @

Yes, determine extent of HM (As, Cu, Pb, Hg, Cd and Zn) PAH and TPH contamination at edge and base of excavated hole.*

5 samples 5m N, S, E & W and base of borehole.

TB21

Yes

Concrete down to 0.5m

0.5m to 5.0m

TCLP test followed by removal of 0.5m to 3.5m to landfill.  Immobilisation if TCLP tests exceed criteria  **.   Remaining depth to be immobilised to 5m *

300 to be removed to landfill

+ 150 @

Yes, determine extent of HM (Cu, Pb, Hg and Zn) and TPH contamination at edge and base of excavated hole.*

5 samples 5m N, S, E & W and base of borehole.

TB22

Yes

Concrete down to 0.5m

0.5 to 1.5m

Immobilisation *

100

Yes, determine extent of HM (Pb) contamination at edge and base of excavated hole.*

5 samples 5m N, S, E & W and base of borehole.

TB23

Yes

Concrete down to 0.5m

0.5 to 4m

Immobilisation*

350

Yes, determine extent of HM (Pb) contamination at edge and base of excavated hole.*

5 samples 5m N, S, E & W and base of borehole.

TB24

Yes

Concrete down to 1.2m

1.2 to 4.2m

Immobilisation*

300

Yes, determine extent of HM (Cu,  Pb and Hg) contamination at edge and base of excavated hole.*

5 samples 5m N, S, E & W and base of borehole.

TB25

Yes

Concrete down to 0.9m.  Down to 1.0m

Depth 1.0m – 4.4m

 

TCLP test followed by removal of 1.0m to 2.9m to landfill.  Immobilisation if TCLP tests exceed criteria **.

Immobilisation for remaining 2.9m to 4.4m*

100 to be removed to landfill

+

240 @

Yes, to determine extent of HM (Pb, Hg) and PAH contamination at edge and base of excavated hole.*

5 samples 5m N, S, E & W and base of borehole.

TB26

Yes

Concrete down to 0.8m

Depth 0.8m – 3.0m

 

TCLP test followed by removal of 0.8m to 3.0m to landfill.  Immobilisation if TCLP tests exceed criteria **.

220 to be removed to landfill.@

Yes, to determine extent of HM (Pb, Cu, Zn, Hg) and TPH contamination.*

5 samples 5m N, S, E & W and base of borehole.

TB27

Yes

Concrete down to 0.5m and clean soil down to 2.0m

2.0 to 4.0m

TCLP test followed by removal of 2.0m to 4.0m to landfill.  Immobilisation if TCLP tests exceed criteria **.

200

Yes, determine extent of HM (Cu and Pb) and PAH contamination at edge and base of excavated hole.*

5 samples 5m N, S, E & W and base of borehole.

TB28

Yes

Concrete down to 0.4m

0.4 to 4.4m

Immobilisation*

400

Yes, determine extent of HM (As, Cd, Cu, Pb, and Zn) contamination at edge and base of excavated hole.*

5 samples 5m N, S, E & W and base of borehole.

TB29

Yes

Concrete down to 0.5m

0.5 to 3.5m

Immobilisation*

300

Yes, determine extent of HM (Cu, Pb, Hg and Zn) contamination at edge and base of excavated hole.*

5 samples 5m N, S, E & W and base of borehole.

TB30

Yes

Concrete down to 0.6m

0.6 to 1.6m

Immobilisation*

100

Yes, determine extent of HM (Pb) contamination at edge and base of excavated hole.*

5 samples 5m N, S, E & W and base of borehole.

Refuse 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.

*          If contamination confirmed by reassurance sampling extract a further 1m into the soil, immobilise and resample.

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

#              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 6055 m3. requiring confirmation).  According to the quantity of contaminated material estimated for each borehole location, the total quantity of contaminated soil should be about 6055m3  .  About 4635m3. of the total volume is estimated to require treatment on site by immobilisation.

@             Broad brush estimate of materials to be transferred to landfill rounded up to nearest 10m3   about 1,420m3, requiring confirmation).


4.7              Procedures for Management of Contaminated Rubble / Ash Waste  Material

4.7.1          There are several issues with regard to the remaining rubble deposits. Untreated the material would be classified as a hazardous (chemical) waste however, after on site treatment the ash material will not be classified as a chemical waste under the Waste Disposal (Chemical Waste) (General) Regulation.  Arrangements must be made for the treatment, removal, packaging, storage and transportation, prior to disposal in line with statutory requirements and codes of practice.

4.7.2          The project proponent (CED) has indicated that sufficient time will be allocated for the proper abatement of all such rubble/ash materials after liaison with the Department of Labour and EPD on the methods to be adopted.  Technical solutions are available that may be applied to the rubble deposits.  It is therefore not considered that the removal of rubble/ash deposits should present an insurmountable environmental problem.

4.7.3          It is recommended that a consultant with experience in the abatement of hazardous wastes will be appointed prior to the appointment of contractors in order to assist with the sampling and analysis, to assist in evaluation the information and prepare an abatement plan for the rubble materials.  Such a plan should 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 Rubble/Ash Waste for Disposal

4.7.4          At this stage the volume of rubble / ash / waste between the chimneys (containing PCDD and PCDF) cannot be precisely determined.  However if the remaining contaminated rubble / ash deposits are in fact confined to the waste heap between the chimneys outside the main hall the total volume would be in the order of about 300m3.  Information available indicates that the contaminated waste is not present elsewhere as indicated by the topmost samples for the soil contamination assessment.  Sufficient time shall 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

4.7.5          The consultant to be appointed by CED for the supervision of the EM&A works must 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.

4.7.6          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 appointed 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 Rubble / Ash Wastes

4.7.7          The ash waste contains a considerable amount of dioxin and in its untreated state would be 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.  Therefore examples of similar projects were sought from the international literature in order to establish any international practice in order to develop appropriate safeguards for handling the material and minimise the potential risk associated with such materials.

4.7.8          Literature searching did not identify any standard international practice on the disposal of dioxin contaminated ash / rubble 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 ranged from 5.580ppb temporary encapsulation in a concrete vault and clay encapsulation of some 200m3 of 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 B.  In other cases off site disposal to landfill with the installation of capping materials have been chosen.

4.7.9          At KTCDA the amount and concentration of dioxin waste (300m3, and from 1.3ppb to 6.8ppb) is of the same magnitude as the quoted example (Appendix B, Tindal Property, Lawrwnceburg, USA, 200m3,up to 5.6ppb).  Therefore action planning for similar quantities 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 the options for the disposal of such waste from the subject site included, disposal via the Chemical Waste Treatment Centre (CWTC), on site immobilisation, or disposal at landfill.

4.7.10      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 stabilised ash would not be classified as a chemical waste.  TCLP would be carried out prior to placement underground, 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) the disposal element of this option was not therefore considered appropriate.

4.7.11      It has been confirmed that the Chemical Waste Treatment Centre (CWTC) is capable of dealing with 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.  In this case the volume of waste has been estimated at up to 300m3 and disposal at the CWTC will not significantly save landfill space.  Due to the limited capacity of the treatment facilities some considerable time would be required for the treatment of the rubble / ash waste.  Due to the amount of waste collection and transportation requirements chemical treatment at the CWTC under controlled conditions is not considered the most appropriate disposal method.

4.7.12      A third alternative is for the waste to be immobilised on site collected and transported for landfilling under controlled conditions without recourse to the CWTC.  TCLP testing would be essential.  The waste would be collected, treated, and transported to landfill under controlled conditions.  This is the recommended option.

Treatment of Rubble / Ash Waste

4.7.13      After discussion with the authorities the proposed method of disposal was to take a more cautious approach than that described in the similar projects which were identified from the international literature.  Appropriate safeguards for handling the material and minimise the potential risk associated with such materials have been developed by the inclusion of pilot testing, TCLP tests, encapsulation of the waste followed by disposal at landfill.  As a fall back option, in the event that the TCLP testing criteria cannot be met, arrangements could be made with the Chemical Waste Treatment Centre (CWTC) for the disposal of part or all of this waste.

4.7.14      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 EPD.  In this case it is envisaged that the process would involve 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. The pilot tests would establish that the dioxin material has been stabilised.  As an extra safeguard the stabilised materials would then be encapsulated in polythene within steel drums prior to being transferred to landfill.  The 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.  The consultants understand that similar approaches to pilot tests on the concentration of cement mixtures for immobilisation have been used at some private sector sites in Hong Kong where soil decontamination for other contaminants has been required.  However, appropriate mixing and stabilising techniques must be developed for the contaminants encountered at the KTCDA site.

4.7.15      The pilot mixtures would then be solidified and subject to TCLP tests with increasing ratio of cement to ash to establish the correct mixture for effective stabilisation to the satisfaction of EPD.  The materials for disposal would then be extracted 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.  As a fall back option arrangements could still be made with the Chemical Waste Treatment Centre (CWTC) for the disposal.

4.7.16      In view of the precautionary approach that has been adopted and the safeguards which have been included there should be no residual effects from the waste disposal.  Given that the concentrations of PCDD/PCDF and quantities of ash encountered at KTCDA are comparable with the levels of contamination in the examples from the literature, the treatment proposals, which are more stringent than used in the identified example (Appendix B) would be adequate for disposal of the contaminated ash.

Protection of Site Workers

4.7.17      The release of contaminants from disturbed rubble / ash waste should be minimised prior to gathering up the rubble / ash waste materials and a mist of water should be sprayed on the waste to thoroughly damp down the material and ensure dust levels are reduced in the removal process.  Care should be taken to ensure that water spraying is carefully controlled to prevent unnecessary surface runoff.  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/rubble.  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.

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

4.7.19      Given the nature of the work and the contaminants involved consideration should be given to the use of decontamination facilities to be provided for the work force to remove decontamination after work.

4.7.20      Preliminary provisions for the protection of workers during the management of the ash removal are presented in the CAR/RAP.

Handling and Transportation

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

4.8              Management of Contaminated Soil Material

4.8.1          At this stage the only opportunity for human exposure to any of the contamination on Site will be if the materials are excavated.  Ground conditions on the Site are contaminated with metals and some organic compounds in isolated locations.

4.8.2          For this Site, 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 material to landfill may be a more suitable remedial option.

Control of Surface Water

4.8.3          Remediation for contaminated soils will be required and actions required are indicated in Table 4.3. Soil remediation activities have the potential to cause water pollution as a result of debris from excavated materials.  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.  Sampling indicates that groundwater is not heavily contaminated and as far as possible water shall be left in situ.  Where this is not possible, it is recommended that water is recycled on site.  Water could be collected and delivered to the refuse bunkers 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.

4.8.4          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.  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.  The quantities of water likely to accumulate and require dewatering could be reused on site and may not require discharge.  Estimated levels of groundwater were 3m to 4m below ground level.  In many cases this is below the contaminants requiring treatment.

4.8.5          It is important however that appropriate measures are implemented to control run-off and drainage and, thereby, prevent high loadings of suspended solids from causing impacts on the identified WSRs.  Proper site management is essential to minimise surface water run-off, soil erosion, soil remediation activities. 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 the event that discharge of surplus water is required, discharges from the site may require mitigation and shall be controlled as indicated below.

4.8.6          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 arise due to the demolition of KTCDA.  In the event that water must be discharged from the site, consent shall be obtained from EPD prior to any discharged being made.  All discharges from the site shall be controlled in order to comply with standards for effluents to be discharged from the site that shall be agreed with EPD.

Demolition Site Run-off and Surface Water Drainage

4.8.7          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.

4.8.8          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.

4.8.9          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.

4.8.10      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.

4.8.11      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.

4.8.12      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

4.8.13      The above mitigation shall apply generally to all excavated stockpiled materials during the soil remediation process.  In practice the consultants experience suggests that runoff from the site can be controlled even though the hard concrete covering 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).

4.8.14      The 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 in an area with a cover and a concrete paved floor 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 provide proper protection minimise ingress of stormwater.  However, impacts associated with this work and other general activities can all be readily controlled through the use of appropriate mitigation measures mentioned above.

General Demolition Activities

4.8.15      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.

4.8.16      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.

4.8.17      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

4.8.18      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.

4.8.19      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

4.8.20      Groundwater 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 and other parameters to be agreed with EPD prior to any consent being given to discharge.  If the concentrations of contaminants exceed the standards the surplus water shall be treated.

4.8.21      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.

4.8.22      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).  The contractor shall therefore make provisions to include for treatment of surplus water 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.

Conclusions

4.8.23      No insurmountable impacts will result from the decontamination work and remediation actions planned for KTCDA 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;

·               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 shall 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.

4.9              Protection of Site Workers During Excavation and Treatment of Soils

4.9.1          Site safety incorporates some basic practices such as the provision of safety boots, hard hat, overalls, gloves and eye protection.  In addition, dust masks should 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 should 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 (Appendix D).

4.9.2          Given the potential for hydrocarbons (TPH) in the soil and groundwater skin contact should 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.

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


5.                  Noise

5.1              Introduction

5.1.1          This section presents an assessment of the noise impacts associated with the demolition and subsequent ground remediation of the KTCDA.  In this study, Noise Sensitive Receivers (NSRs) have been identified within 300m from the project boundary.  The following assessment was assumed to use the conventional top-down method for demolition of the Site.  The worst case impacts on these receivers were then predicted.

5.1.2          Potential noise impacts on the NSRs will be a significant concern during the demolition of the KTCDA.  Where necessary, noise mitigation measures are recommended to reduce the noise impacts at the NSRs.

5.1.3          It is assumed that the demolition for KTCDA will take place as soon as possible in order to allow for future developments on and near the Site.  The earliest start date is likely to be 2003, with demolition works lasting about one year and remediation works approximately six to eight months.

5.2              Government Legislation and Standards

5.2.1          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 during restricted hours, (i.e. between 7 p.m. and 7 a.m. on any day not being a general holiday and at any time on a general holiday including Sunday) by means of construction noise permits (CNP).  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 Hong Kong Island Designated Area as shown in Plan No. EPD/NP/HKI-01.

5.2.2          If construction works during restricted periods are needed, a CNP will be required.  However there is no guarantee that a CNP will be issued for the project, despite any description or assessment made in the EIA Report on construction noise aspects.  The Noise Control Authority will consider a well-justified CNP application, once filed, for construction works within restricted hours as guided by the relevant Technical Memoranda issued under the NCO.  The Noise Control Authority will take into account of contemporary status of adjoining land uses and any previous complaints against construction activities at the Site before making his decision in granting a CNP.  Nothing in the EIA Report shall bind the Noise Control Authority in making their decision.  If a CNP is to be issued, the Noise Control Authority may include in it any condition they think fit.  Failure to comply with any such conditions will lead to cancellation of the CNP and potential prosecution action under the NCO.

5.2.3          Outside the restricted periods general construction works must meet any contractual noise standards for daytime construction activities (usually those given 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 5.1 summarises the non-statutory daytime noise criteria.  Since the Project is expected to be carried out during daytime, the noise standards stated in table below have been used for assessment purposes.  Assessment has been undertaken in accordance with the guidelines given in Table 1B, Annex 5 of the EIAO-TM.


Table 5.1         Noise Standards for Daytime Construction Work

Land Use

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.

5.2.4          Under the subsidiary regulations of the NCO, hand held percussive breakers and air compressors must comply with a stringent noise standard and be fitted with a "noise emission label" before they can be used for work.  The maximum permissible sound 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.

5.3              Existing Noise Conditions

5.3.1          A number of industrial uses, including warehouses and wharves are located around the Site.  The study area is predominantly influenced by road traffic and industrial operations.  The operation noise of a bus terminus also contributes to the background noise at the Site.

5.4              Noise Sensitive Receivers

5.4.1          NSRs are formally defined as residential premises, hotel, hostel, temporary housing accommodation, hospital, medical clinic, educational institution, place of public worship, library, court of law or performing arts centre.

5.4.2          Residential, Government, Institutional and Community uses surround the KTCDA Site and many of these are elevated and overlook the Site.  The nearest rank of sensitive receivers is discussed in Section 2.  These include:

·               Kennedy Town Police Married Quarters;

·               The Mount Davis Cottage Area;

·               The new Housing Society development (Cayman Rise) at Ka Wai Man Road;

·               Residential buildings at Cadogan Street;

·               Manhattan Heights high rise development at Kennedy Town New Praya;

·               Government, Institutional and Community uses at St Lukes Church School, St Lukes Settlement, Jockey Club Clinic, Victoria Mortuary and the Bayanihan Centre.

5.4.3          Site observations indicate that the Kennedy Town Jockey Club Clinic and schools in the vicinity of the Site have already provided with window insulation and air-conditioning.  Therefore they are not considered critical constraints to the Project at this stage but has been included in the EIA.

5.4.4          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.  Residential towers south of Victoria Road and at Ka Wai Man Road and the future URA development sites east of the Site are likely to be the most vulnerable of construction noise impacts.  Table 5.2 lists the representative NSRs and their horizontal distances from the notional noise source and Table 5.3 summarises the estimated distances between the chimneys and the receivers.  Locations of NSRs are shown in Figure 2.1.

Table 5.2         Representative Noise Sensitive Receivers

NSR

Building

Horizontal Distance from notional noise source (m)

Use

KT-N1

Cheong Kat Mansion

75

25-storey high residential block

KT-N2

Sai Wan New Mansion

75

12-storey high residential block

KT-N3

Centenary Mansion

75

27-storey high residential block above 4-storey  high podium

KT-N4

Cayman Rise

75

31-storey high residential block above 5-storey high podium

KT-N5

Bayanihan Centre Kennedy Town

100

Philippine overseas worker training school

KT-N6

Jockey Club Clinic

75

3-storey high building

KT-N7

St. Luke's Church School

100

6-storey high school

 

Table 5.3         Estimated Distances from Chimneys

NSR

Building

Horizontal Distance from Chimney A (m)

Horizontal Distance from Chimney B (m)

Horizontal Distance from Chimney C (m)

KT-N1

Cheong Kat Mansion

300

250

150

KT-N2

Sai Wan New Mansion

288

238

138

KT-N3

Centenary Mansion

250

200

138

KT-N4

Cayman Rise

163

138

163

KT-N5

Bayanihan Centre Kennedy Town

113

138

250

KT-N6

Jockey Club Clinic

113

100

175

KT-N7

St. Luke's Church School

150

138

200

 

5.5              Potential Sources of Impact

5.5.1          The potential noise impacts arising from the demolition of the Site result from the operation of demolition plant and vehicles.  Major noise generating activities associated with the demolition works include mechanical demolition of the building structures and material transfer within the Site.  Impacts also have the potential to occur as a result of ground remediation works.  This aspect has also been included for assessment separately as remediation will not commence until completion of the demolition works.

5.5.2          The demolition of the Site is expected to take about 12 months, with work commencing in 2003.  Work is anticipated to be winding down in the last three months of the project.  The debris storage would be temporary and waste materials would be taken off-site as soon as possible. 

5.5.3          The mechanical demolition of the buildings would be carried out at the beginning of the demolition period while the demolition of chimney(s) would be likely to be undertaken at a later stage.  These two activities will not, therefore, be carried out concurrently.  Ground remediation works would follow on from demolition activities.

5.5.4          It is also noted that demolition activities would not be carried out simultaneously at the same location, but spread over the whole Site.  The demolition of the chimneys would follow on after the main abattoir, incinerator and bus depot buildings.

5.6              Assessment Methodology

5.6.1          The assessment of the potential noise impact from the demolition works is based on standard acoustic principles.  The assessment procedure has made reference to the Technical Memorandum on Noise from Construction Work other than Percussive Piling (TMCW) issued under the NCO.  Where no sound 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.

5.6.2          The TMCW specifies sound power levels of common construction equipment, assessment procedures 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) as listed in the Technical Memorandum.

·               Distance Attenuation - All items of PME have been considered to be grouped at the notional source position, which 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.  However, for the demolition of chimneys, all items of PME was assumed at the location of the nearest chimney to the concerned NSR.

·               Barrier Effect - According to the Technical Memorandum, a negative correction of 5 dB(A) or 10 dB(A) can be applied to the predicted noise levels depending on the situation stipulated in the TMCW.

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

5.6.3          The noise emissions at demolition sites will be caused by mechanical plant for demolition operations.  Demolition works using such PME and truck movements are the two major noise generation activities for demolition.  For a worst-case scenario, it was assumed in the model that all equipment would be fully utilised, simultaneously, although this is not likely to be the case.  An inventory of noise sources including demolition equipment and other associated construction equipment was compiled based on consultation with experienced demolition engineers and the consultant’s experience of other demolition sites.  The Project Proponent has indicated that the base suite of plant is practical and practicable for completing the works.  Table 5.4 lists the type and number of equipment and plant likely to be used.  Table 5.5 lists the type and number of equipment likely to be used for the ground remediation works.

Table 5.4         Base Suite of Demolition/Construction Plant

Construction Plant

CNP No.

SWL, dB(A)

Quantity

Months 1-2

Months 3-4

Months 5-9

Generator, silenced

CNP102

100

2

2

2

Air Compressor

CNP003

104

1

3

3

Crawler Mounted Hydraulic Breaker

CNP028

122

1

4

4

Excavator/Backhoe

CNP081

112

1

3

3

Crawler/Mobile Crane

CNP048

112

1

4

4

Lorry/Dump Truck

CNP067

117

2

5

10

Pneumatic Breaker

CNP026

114

1

5

5

Chain Saw

CNP203

115

1

3

3

Cutter

CNP021

90

1

2

2

Water Pump

CNP281

88

8

8

8

Crane Shaft and Derrick*

CNP049

95

1

3

3

Total SWL per month dB(A)

125

131

132

                *                      to lift large sections of cladding or reinforced concrete to ground level.

Table 5.5         Base Suite of Soil Remediation Construction Plant

Construction Plant

CNP No.

SWL, dB(A)

Quantity

Months 10-11

Months 12-15

Months 16-17

Generator, silenced

CNP102

100

2

2

2

Air Compressor

CNP003

104

2

2

2

Excavator/Backhoe

CNP081

112

2

2

2

Lorry/Dump Truck

CNP067

117

2

3

3

Pneumatic Breaker

CNP026

114

2

2

2

Water Pump

CNP281

88

4

4

4

Ballast Tamper

CNP029

105

1

1

1

Concrete Mixer

CNP045/046

96

2

2

2

Vibratory Compactor

CNP050

105

2

2

2

Total SWL, dB(A) per month

123

124

124

 

5.6.4          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 assuming no mitigation.  All ground remediation works will be undertaken at ground level.

5.7              Evaluation of Impacts

5.7.1          The likely unmitigated noise impacts on the NSRs from demolition works and ground remediation works were modelled and the results are presented in Tables 5.6 and 5.7 respectively.  The modelling results show that minor noise exceedance would be expected at the earlier stages of the demolition.  As the project proceeds, the extent of the proposed demolition activities increases such that the noise standard of 75dB(A) would be exceeded at all NSRs.  A maximum noise exceedance of up to 14dB(A) was predicted at nearest receivers KT-N1 to KT-N4.  Mitigation measures to suppress the noise from the Site are therefore necessary.

Table 5.6         Predicted Unmitigated Noise Levels from Demolition

NSR

Period

SWL, dB(A)

DA, dB(A)

FC, Db(A)

PNL, dB(A)

KT-N1

Months 1-2

125

-46

3

82

Months 3-4

131

-46

3

88

Months 5-9

132

-46

3

89

KT-N2

Months 1-2

125

-46

3

82

Months 3-4

131

-46

3

88

Months 5-9

132

-46

3

89

KT-N3

Months 1-2

125

-46

3

82

Months 3-4

131

-46

3

88

Months 5-9

132

-46

3

89

KT-N4

Months 1-2

125

-46

3

82

Months 3-4

131

-46

3

88

Months 5-9

132

-46

3

89

KT-N5

Months 1-2

125

-48

3

80

Months 3-4

131

-48

3

86

Months 5-9

132

-48

3

87

KT-N6 *

Months 1-2

125

-46

3

82

Months 3-4

131

-46

3

88

Months 5-9

132

-46

3

89

KT-N7

Months 1-2

125

-48

3

80

Months 3-4

131

-48

3

86

Months 5-9

132

-48

3

87

Note:       SWL        denotes sound power level

DA           denotes distance attenuation and distance referred to Table 5.2

FC           denotes façade correction

PNL         denotes predicted noise level

*              The Jockey Club Clinic (KT-N6) is provided with window insulation and air-conditioning and does not rely on operable windows for ventilation.  Predicted Noise Levels at this locations are for indication only.

 

Table 5.7         Predicted Unmitigated Noise Levels from Ground Remediation

NSR

Period

Total SWL, dB(A)

DA, dB(A)

FC, dB(A)

PNL, dB(A)

KT-N1

Months 10-11

123

-46

3

80

Cheong Kat Mansion

Months 12-15

124

-46

3

81

 

Months 16-17

124

-46

3

81

KT-N2

Months 10-11

123

-46

3

80

Sai Wan New Mansion

Months 12-15

124

-46

3

81

 

Months 16-17

124

-46

3

81

KT-N3

Months 10-11

123

-46

3

80

Centenary Mansion

Months 12-15

124

-46

3

81

 

Months 16-17

124

-46

3

81

KT-N4

Months 10-11

123

-46

3

80

Cayman Rise

Months 12-15

124

-46

3

81

 

Months 16-17

124

-46

3

81

KT-N5

Months 10-11

123

-48

3

78

Bayanihan Kennedy Town Centre

Months 12-15

124

-48

3

79

 

Months 16-17

124

-48

3

79

KT-N6

Months 10-11

123

-46

3

80

Jockey Club Clinic

Months 12-15

124

-46

3

81

 

Months 16-17

124

-46

3

81

KT-N7

Months 10-11

123

-48

3

78

St. Luke's Church School

Months 12-15

124

-48

3

79

 

Months 16-17

124

-48

3

79

Note :      SWL        denotes sound power level

                                DA           denotes distance attenuation

                                FC           denotes façade correction

                                PNL         denotes predicted noise level

*              The Jockey Club Clinic (KT-N6) is provided with window insulation and air-conditioning and do not rely on operable windows for ventilation.  Predicted Noise Levels at these locations are for indication only.

 

5.8              Mitigation Measures

5.8.1          There are a variety of mitigation techniques which can be utilised.  Cantilevered barriers can be designed to cover over plant at ground level as well as simple vertical shields.  Silenced equipment is also potentially very effective in reducing noise.  The modification of the Site hoarding into a noise barrier is also possible to mitigate noise levels. Movable barriers shall also be considered for deployment close to noisy equipment.  Where required, these should be made of panels with a superficial surface density of at least 7 kg/m2.

5.8.2          As presented above, the demolition works are likely to cause noise impacts at most of NSRs.  The following noise control measures should be considered for incorporation into Contract documents to minimise noise nuisance to within acceptable levels arising from the works:

·               Silenced and super silenced type equipment;

·               Reduction in number of plant operating simultaneously;

·               Movable barriers as noise shields;

·               Use of modified site hoarding to a perimeter noise barrier as a noise shield; and

·               Re-scheduling and restricting hours of operation of noisy tasks.

5.8.3          The DCDB notes that certain methods can assist in reducing noise and vibration.  The assessment has assumed a worst possible case.  The use of silenced equipment and portable barriers for plant positioned at ground level (compressor, generator) will generally be sufficient to control noise to acceptable levels.  Portable barriers should also be used at higher levels wherever practicable in line with EPD recommendations (Practical Guide to Reduction of Noise from Construction Works) and silenced equipment used in line with BS 5228 (1997) is recommended.

5.8.4          These recommendations shall not rule out the use of other more environmentally friendly (quieter) techniques where these are practicable.  It is recommended that the selected non-blasting demolition technique, identified in the DCDB, be carried through in the detailed design stage to minimise noise and vibration.  In addition careful consideration and positioning of portable noise barriers to allow noise attenuation wherever practicable and the implementation of these recommendations through the environmental monitoring and audit programme will control the noise well within acceptable levels.

5.8.5          It is not possible at this stage to give details of the positions of portable barriers at locations of PME as this will depend on the detailed demolition plans of the selected contractor(s). Whereas in the calculations it has been assumed that up to four crawler mounted hydraulic breakers may be in use, in practice it is unlikely that all four would be in use simultaneously.  However as this possibility cannot be ruled out it is necessary to propose mitigation to attenuate the noise to within the target noise criterion.

5.8.6          In practice some sites have also used practices such as shrouding the striking point of the concrete breaker tip with an acoustically attenuating mattress.  This can be particularly effective in controlling high frequencies.  In addition it should be possible to arrange for some of the removal of the demolition waste to take place from the harbour side of the abattoir and incinerator buildings.  If this can be implemented further noise reductions would be possible although neither of the above has been included in the calculations.

5.8.7          If none of these practices are sufficiently effective then the on-time for each crawler mounted breakers could be restricted, or hydraulic crushers could be considered for the substitution of the crawler mounted breakers[1]. Altogether, in practice, a variety of techniques can be employed to minimise noise.

5.8.8          Through the use of a variety of techniques used above it will be possible to control the noise to acceptable levels.  However to ensure that the noise is reduced to and acceptable level such that no insurmountable problems would be anticipated the recommendation is that some the original suite of equipment is reduced and the demolition period is extended beyond month 9 to month 12.  In practice this would allow a longer demolition period with a little less equipment in Table 5.8.  The Project Proponent has indicated that the revised suite of plant is also practical and practicable for completing the works.  Table 5.8 lists the type and number equipment plant that can be used for demolition and ground remediation works.

5.8.9          To ensure that the noise mitigation measures are actually implemented on-site, specific clauses should be incorporated into the contract documents.  Furthermore, the proponent will provide an EM&A team with experienced staff on similar sites in Hong Kong to supervise/audit the environmental aspects of demolition and soil remediation works.  This supervision should ensure that the contractual clauses are followed and that prevention of noise nuisance is given a high priority during the demolition and soil remediation works on the Site.

Table 5.8         Revised Suite of Demolition and Ground Remediation Plant

Construction Plant

CNP No. / BS5228 Ref. No.

SWL, dB(A)

Quantity

Demolition of Buildings other than Chimneys

Crawler Mounted Hydraulic Breaker

Table C8/13

110

2

Excavator/Backhoe

Table C3/97

105

2

Lorry/Dump Truck

Table C9/27

105

2

Water Pump

CNP281

88

4

Total SWL, dB(A) for demolition of Buildings other than Chimneys

115 dB(A)

 

Demolition of Chimneys Only

Pneumatic Breaker

Table C2/10

110

3

Cutter

CNP021

90

3

Air Compressor

CNP003

104

3

Generator, silenced

CNP102

100

3

Excavator/Backhoe

Table C3/97

105

3

Lorry/Dump Truck

Table C9/27

105

4

Water Pump

CNP281

88

3

Mobile Crane

Table C7/114

101

1

Total SWL, dB(A) for demolition of Chimneys Only[1]

118 dB(A)

 

Ground Remediation

Generator, silenced

CNP102

100

2

Air Compressor

CNP003

104

1

Excavator/Backhoe

Table C3/97

105

1

Lorry/Dump Truck

Table C9/27

105

2

Pneumatic Breaker

Table C2/10

110

1

Water Pump

CNP281

88

4

Ballast Tamper

CNP029

105

1

Concrete Mixer

CNP045/046

96

2

Vibratory Compactor

CNP050

105

2

Total SWL, dB(A) for Ground Remediation

115 dB(A)

Note :      [1]           The quantity of equipment was assumed  for demolition of three chimneys simultaneously.

 

5.8.10      Table 5.8 summarises mitigated sound power levels of the proposed equipment for demolition.  With the above measures, it is expected that the noise from the Site could be reduced and the predicted mitigated noise levels at the NSRs from demolition works are presented in Tables 5.9 and 5.10.

 

Table 5.9         Predicted Mitigated Noise Levels from Demolition of Buildings other than Chimneys

NSR

SWL, dB(A)

DA, dB(A)

FC, dB(A)

PNL, dB(A)

KT-N1

115

-46

3

72

KT-N2

115

-46

3

72

KT-N3

115

-46

3

72

KT-N4

115

-46

3

72

KT-N5

115

-48

3

70

KT-N6 *

115

-46

3

72

KT-N7

115

-48

3

70

Note:       SW           denotes sound power level

DA           denotes distance attenuation and distance referred to Table 5.2

FC           denotes façade correction

PN           denotes predicted noise level

*              The Jockey Club Clinic (KT-N6) is provided with window insulation and air-conditioning and does not rely on operable windows for ventilation.  Predicted Noise Levels at these locations are for indication only.

 

Table 5.10       Predicted Mitigated Noise Levels from Demolition of Chimneys Only

NSR

SWL, dB(A)

DA, dB(A)

FC, dB(A)

PNL, dB(A)

KT-N1

118

-52

3

69

KT-N2

118

-51

3

70

KT-N3

118

-51

3

70

KT-N4

118

-51

3

70

KT-N5

118

-49

3

72

KT-N6 *

118

-48

3

73

KT-N7

118

-51

3

70

Note:       SW           denotes sound power level

DA           denotes distance attenuation and distance referred to the shortest distance in Table 5.3

FC           denotes façade correction

PN           denotes predicted noise level

*              The Jockey Club Clinic (KT-N6) is provided with window insulation and air-conditioning and does not rely on operable windows for ventilation.  Predicted Noise Levels at these locations are for indication only.

 

5.8.11      The above tables show that even with all plant operating simultaneously the adopted mitigation measures will effectively reduce the noise to acceptable levels and the noise criteria will be satisfied at all NSRs.  However, in practice, not all the equipment would be expected to be operating simultaneously.  Thus the actual situation would be better than the predicted case and the noise criteria will be satisfied at all NSRs.

5.8.12      Environmental monitoring and audit (EM&A) for noise generated during the demolition and ground remediation is also recommended at the nearby NSRs to ensure that the noise criteria will not be exceeded (Section 8).

5.8.13      Table 5.8 summarises mitigated sound levels of the proposed equipment for ground remediation.  With the these measures, it is expected that the noise from the Site could be reduced and the predicted mitigated noise levels at the NSRs from ground remediation works are presented in Table 5.11.

Table 5.11       Predicted Mitigated Noise Levels (Ground Remediation)

NSR

SWL, dB(A)

DA, dB(A)

FC, dB(A)

PNL, dB(A)

KT-N1

115

-46

3

72

KT-N2

115

-46

3

72

KT-N3

115

-46

3

72

KT-N4

115

-46

3

72

KT-N5

115

-48

3

70

KT-N6 *

115

-46

3

72

KT-N7

115

-48

3

70

Note:       SW           denotes sound power level

DA           denotes distance attenuation and distance referred to Table 5.2

FC           denotes façade correction

PN           denotes predicted noise level

*              The Jockey Club Clinic (KT-N6) is provided with window insulation and air-conditioning and does not rely on operable windows for ventilation.  Predicted Noise Levels at this locations is for indication only.

Conclusions

5.8.14      With mitigation such as the use of quieter plant and the reduction in plant items, the predicted noise levels at the NSRs will be within the established criteria, for KT-N1 to KT-N7 during both demolition and ground remediation.  Therefore, noise exceedances are not expected at these locations.  However, worst case noise levels are predicted to be relatively high or near to established criteria.  Mitigation measures have been recommended to reduce the predicted noise levels at the NSRs.  EM&A procedures for demolition noise are recommended at the nearby NSRs to ensure that the necessary controls are effectively implemented and noise criteria are not exceeded.


6.                  Air Quality

6.1              Introduction

6.1.1          The preferred demolition method is not blasting, but top-down deconstruction.  Routine statutory controls on dust arising from demolition are always applied to control dust impact and dust impact assessment would only required if a blasting method is to be used for the demolition.  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 dust levels at the ASRs will be within the established criteria, therefore excessive dust during demolition works is not expected.  In order to provide some reference material with regard to air quality, all Air Sensitive Receivers (ASRs) within 500m proximity to the Site have been identified.

Table 6.1         Representative Air Sensitive Receivers

ASR

Building

Horizontal Distance from nearest dust  source (m)

Use

KT-A1

Cheong Kat Mansion

25

25-storey high residential block

KT-A2

Sai Wan New Mansion

25

12-storey high residential block

KT-A3

Centenary Mansion

25

27-storey high residential block above 4-storey  high podium

KT-A4

Cayman Rise

40

High-rise residential block

KT-A5

Bayanihan Centre Kennedy Town

50

Philippine overseas worker training school

KT-A6

Jockey Club Clinic

15

3-storey high building

KT-A7

SKH Lui Ming Coi Memorial School

50

6-storey high school

            N.B. Notional dust source is the nearest site boundary

6.1.2          Potential dust impacts on the ASRs are the major concern during the demolition of the KTCDA.  Mitigation measures are required under the Air Pollution Control (Construction Dust) Regulation, to reduce the air quality impacts at the ASRs.

6.2              Government Legislation and Standards

6.2.1          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 6.2 below.

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

6.3              Dust Suppression Measures

6.3.1          The fugitive dust emissions relevant to this demolition Site are associated with general deconstruction and mechanical demolition of structures, land clearing, and the movement of trucks.  Whereas the site is generally paved there will little movement of trucks on unpaved surfaces. The need to remove the cement surface during soil remediation may result in the movement of some trucks over unpaved surfaces during the soil remediation phase of the works.  Overall the dust 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.

Table 6.2         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 (25oC) 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).

 

6.3.2          In order that nuisance to residential sensitive receivers is minimised, it is important to minimise dust emissions from construction activities.  In 1997, the Air Pollution Control (Construction Dust) Regulation came into effect to control dust emission from construction works.  Appropriate dust control measures should be implemented during construction stage in accordance with the requirements in the Air Pollution Control (Construction Dust) Regulation.  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;

·               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.

6.3.3          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 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 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 to ensure that the dust criteria will not be exceeded.  Whereas it is not expected that asbestos fibre would be liberated from the asbestos abatement works, EM&A for asbestos fibre has been conducted at the boundary on Government sites and this is recommended at the Site boundary to provide reassurance that the asbestos fibre criteria are not be exceeded.

6.4              Vehicle Emissions

6.4.1          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. Kennedy New Praya Rd) are greater than ten 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.

6.5              Odour

6.5.1          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.

6.6              Conclusions

6.6.1          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.


7.                  Waste Management

7.1              Introduction

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

7.1.2          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.

7.2              Assessment Criteria and Methodology

Assessment Criteria

7.2.1          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);

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

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

7.3              Waste Disposal Ordinance

7.3.1          The Waste Disposal Ordinance (WDO) defines waste as any substance or article which 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 are defined as chemical waste and disposed of in line with the Code of Practice on Handling, Transportation and Disposal of Asbestos Wastes.

7.3.2          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.

7.3.3          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 notifications and consents from all countries concerned are required before the commencement of any proposed shipment of hazardous waste.  Under the amendment, 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, and a maximum fine of HK$500,000 and two years’ imprisonment for a second or subsequent offence.

7.4              Waste Disposal (Chemical Waste) (General) Regulation

7.4.1          Chemical wastes as defined under the Waste Disposal (Chemical Waste) (General) Regulation include substances such as scrap material, or unwanted substances listed under Schedule 1 of the Regulations if such substance or chemical occurs 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.

7.4.2          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. 

7.4.3          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’.

7.4.4          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.

7.5              Dumping at Sea Ordinance

7.5.1          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 KTCDA.

7.6              Land (Miscellaneous Provisions) Ordinance

7.6.1          Demolition wastesConstruction and Demolition (C&D) materials which are wholly inert may be taken to public dumpsfilling areas.  Public dumps filling areas usually form part of land reclamation schemes and are operated by the Civil Engineering Department (CED).  The Land (Miscellaneous Provisions) Ordinance (Cap 28) requires that dumping licences are obtained by individuals or companies who deliver suitable demolition wastes to public dumpsfilling areas.  The licences are issued by the CED under delegated powers from the Director of Lands.

7.6.2          Individual licences and windscreen stickers are issued for each vehicle involved.  Under the licence conditions public dumps filling areas 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 filling area supervisor.

7.7              Public Cleansing and Prevention of Nuisance s By-LawsRegulation

7.7.1          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$1025,000 and imprisonment for up to 6 months.

7.8              Additional Guidelines

7.8.1          There are also other documents which 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

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

7.8.2          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.

Assessment Methodology

7.8.3          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.

7.9              Impacts of Wastes Generated from Demolition

Potential Sources of Impact

General

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

·               Demolition Construction and Demolition (C&D) wastematerials;

·               Chemical waste; and

·               General refuse.

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

Demolition C&D WasteMaterials

7.9.3          Demolition C&D waste 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 demolished.  Demolition C&D waste 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, banisters);

·               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).

7.9.4          Those items marked with an asterisk are inert materials which are considered suitable for public dumpingfilling.

7.9.5          Demolition C&D wastes materials are typically generated simultaneously in mixed form and the individual waste materials may be altered (e.g. painted).  The final volume and composition of C&D waste requiring disposal to public filling area following the demolition at KTCDA will be dependent on the demolition procedure and material recovery practices employed.  At this stage, it is not possible to predict accurately the amount of demolition wasteC&D material that will require public filling, although it is estimated that at least 90% of the total (by volume) would require disposal at public filling area.  An estimate of principal demolition products is made in Table 7.1 below and it assumed that all material will require removal from the Site.

Table 7.1         KTCDA Principal Demolition Products

Buildings

Concrete Volume (m3)

Weight of Rebar (kg)

Refrigeration Block

2,800

50,000

Slaughterhouse Block

4,000

72,000

Lairage Block

10,000

177,000

Incineration Plant

1,200

16,000

Chimneys

1,000

13,000

Total

19,000

328,000

 

Chemical Waste

7.9.6          Chemical Waste, as defined under the Waste Disposal (Chemical Waste)(General) Regulation, includes any substance being scrap material, or unwanted substances specified under Schedule 1 of the Regulation.  A complete list of such substance is provided under the Regulations, however substances likely to be generated by decommissioning of the KTCDA will, for the most part, arise from the removal of asbestos containing materials (ACM).  It is understood that all bulk ACM at the KTIP has been removed and the remaining 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.

General Refuse

7.9.7          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.

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

Prediction and Evaluation of Impacts

General

7.9.9          The nature and amount of the waste arisings from the demolition of the KTCDA 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 Materials

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

7.9.11      The management of demolition wastesC & D material is unlikely to raise any long term concerns because of the inert nature of most of the wastes materials which may, therefore, be disposed of at public dumpsfilling areas.  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 dumps filling areas for reclamation works and other mixedC&D  wastes at a controlled landfill site.  The segregation and recovery of materials for recycling will also minimise waste arisingsC&D waste requiring landfill disposal.  It will also assist in minimising costs in anticipation of any future landfill charges.

7.9.12      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 KTCDA 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 which can be disposed of at public dumps filling areas (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

7.9.13      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.

7.9.14      Chemical wastes will arise principally as a result of the removal of any ACM cladding.  An AIR and AAP have been completed which assess the impacts from asbestos wastes and outline the procedures for dealing with the remaining low risk ACM.

7.9.15      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

7.9.16      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.

7.9.17      The environmental impacts from the various waste types are summarised in Table 7.2.

Table 7.2         Summary of Waste Management Impacts

Waste Type

General Evaluation

Demolition WasteC&D material

The total quantities of demolition wastesC&D material which will be generated will be up to  about 250te 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 materials 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, including up to 1,000m3 of asbestos containing roofing materials and louvres, 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.

 

7.10          Mitigation Measures

Introduction

7.10.1      This section sets out recycling, storage, transportation and disposal measures which are recommended to avoid or minimise potential adverse impacts associated with waste arising from the demolition of the KTCDA, under the headings of each waste type.  The Contractor should incorporate these recommendations into a comprehensive on-site waste management plan.  Such a waste management plan 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

7.10.2      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

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

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

7.10.4      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 Materials

7.10.5      At this stage a broad estimate is that approximately 2500m3 of demolition wasteC&D materials will arise at the KTCDA 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.

7.10.6      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 areawith the latter being the preferred option.  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 filling areas dump sites, should be segregated from any ‘contaminated’ wastes which will require landfill disposal.

7.10.7      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.

7.10.8      If landfill disposal has to be used, the C& D wastes will most likely be delivered to the SENT Landfill.

7.10.9      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

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

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

7.10.12   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.

7.10.13   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.

7.10.14   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.

7.10.15   The Business Environment Council Technology operates a Waste Exchange Scheme which can assist in finding receivers or buyers.

7.10.16   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.

7.10.17   EPD have indicated that the PCDD/PCDF contaminated rubble/ash waste (300m3 approx.) between the chimneys at KTIP should ideally be immobilised and disposed of to landfill.  No PCDD/PCDF were detected at 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 above ground.  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.   This material must be removed by an appropriately qualified specialist contractor and must collected, transported to landfill in accordance with criteria and conditions specified by EPD and as described earlier in this report.

General Refuse

7.10.18   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 C&D material and chemical wastes, daily to minimise odour, pest and litter impacts. The burning of refuse on construction sites is prohibited by law.

7.10.19   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.

7.10.20   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

7.10.21   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.

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

Trip-ticket system

7.10.23   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.  The system should be subject to independent auditing.

Training and Records of wastes

7.10.24   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).

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

Waste Management Requirements

7.10.26   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.

7.10.27   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:

·         Public fill (inert) for disposal at public filling areas;

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

·         Chemical waste for treatment at licensed facilities; and

·         General refuse for disposal at landfill.

7.10.28   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. 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 filling barging point on Area 30D.

7.10.29   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 filling 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) materials would help to ensure that the former are taken to public filling areas, while the latter are properly disposed of at controlled landfills. Since public fill brought to public filling areas will not attract a charge, while C&D waste taken to landfill may attract some charge in the future, separating C&D material may also help to reduce waste disposal costs, should landfill charging be introduced.

7.10.30   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.

7.11          Waste Management Planning

7.11.1      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.

Framework for the Waste Management Plan

7.11.2      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.

7.11.3      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.

7.11.4      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) shall be transferred for disposal at landfill and chemical waste shall be collected and dispatched for treatment at licensed facilities and general refuse shall be collected and transferred for disposal at landfill.  There will be no excavation in the demolition phase therefore the majority of inert waste can be delivered to public filling areas.  For the C&D material it is anticipated that by the time the demolition works commence the Kai Tak Waste Recycling facility will have been commissioned and will be available.  In addition it is understood that the Sai Ying Pun public fill barging point will be available for the forseeable future.

7.11.5      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).

7.11.6      The WMP shall confirm the estimated total quantities of C&D materials that will be generated (currently estimated at about 2500m-3 per month) 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).

7.11.7      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 1,000m3) 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.

7.11.8      The WMP shall detail the provisions for monitoring the disposal of C&D and solid wastes at public filling facilities and landfills.  It is estimated that at the peak of operations up to 40 lorries per day would be required for the removal of C&D material.  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.

7.11.9      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

7.11.10   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.

7.11.11   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.

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


8.                  Environmental Monitoring and Audit

8.1              Introduction

8.1.1          In this Section recommendations for the environmental monitoring and audit (EM&A) programme for the demolition of the KTCDA are outlined, taking account of the findings of the EIA.  A more detailed, 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.

8.1.2          This EIA has identified that EM&A will be necessary for noise and dust impacts.  Monitoring and reporting of the removal and disposal of any contaminated materials, is required based on the soil contamination assessment and this is also included in the EM&A Manual.  The CAR and RAP contain full details of the methodology for the disposal of contaminated materials which will proceed after the demolition.

8.1.3          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 unforeseen circumstances.

8.1.4          The Proponent will need to appoint an environmental professional acceptable to EPD to design, implement and supervise the Site cleanup, as required.  All the clean up activities will comply with all prevailing environmental legislation (Air, Noise, Water and Waste) as well as not to cause any land contamination.

8.2              Environmental Monitoring and Audit

8.2.1          EM&A will be undertaken during the demolition of the KTCDA.  The overall objectives of the EM&A programme are as follows:

·               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.

8.2.2          The monitoring will be undertaken by Proponent’s Site staff under the direction of a nSenior environmental professional with 7 years’ experience (environmental) and will consist of:

·               1-hour and 24-hour TSP monitoring at three locations on the Site boundary facing ASRs KT1, KT3 and KT5;

·               noise monitoring at three locations near the Site boundary facing the Site at KT1, KT3 and KT5; and

·               as appropriate, the removal and disposal of contaminated material and surplus groundwater, (at this stage underground tank cleaning and backfilling are not thought to be required).

8.2.3          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.

8.3              Event Contingency Plans (ECPs)

8.3.1          The purpose of the ECPs 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.

8.3.2          The ECPs 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.

8.4              Reporting

8.4.1          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, in accordance with the TMEIA 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 8.1         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 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

KTCDA 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.

CED and Contractor

As above

A

4

2

Demolition

 

 

 

 

 

A

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

KTCDA work areas. Duration of the demolition

C#

8

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

As 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

Improved Site Hoarding

Boundary hoarding to be modified in form of noise barrier to provide effective noise screening and made of panels with a superficial surface density of at least 10 kg/m3

CED’s Contract`or

As above

C

Env. Permit

F

Demolition Sequence

Include careful consideration and positioning of portable noise barriers to allow noise attenuation. 

CED’s Contractor

As above

C

8

G

Portable Noise Barriers

Moveable noise barriers shall be provided close to PME in cases where, in the opinion of the Engineer, such PME has the potential to cause noise nuisance to sensitive receivers and where a benefit will result.  Such barriers shall be made of panels with superficial surface density not less than 10 kg/m3.

CED’s Contractor

As above

C

Env. Permit

H

Plant Operation

Modify continuous operational periods for noisy plant to comply with noise criteria.

CED’s Contractor

As above

C

Env Permit

I

Demolition Techniques

Selection of non-blasting demolition techniques to minimise noise and vibration. 

CED’s Contractor

As above

C

8

J

Plant maintenance

 

All plant shall be maintained to prevent any undue noise nuisance.

CED’s Contractor

As above

C

2, 3

K

Wheel wash

All wheel wash water shall be diverted to a sediment pit.

CED’s Contractor

As above

C

5

L

Sediment control

Sediment removal facilities shall provided and be maintained and excavated as necessary to prevent sedimentation of channels.  Perimeter channels should be provided before demolition starts.  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

M

Surface water diversion

All clean surface water shall be diverted around the site.

CED’s Contractor

As above

C

5, 12

N

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

O

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

P

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

Q

Material containers

All empty bags and containers shall be collected for disposal.

CED’s Contractor

As above

C

6,7

R

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

S

Neighbourhood nuisance

All complaints regarding construction works shall be relayed to the environmental team.

CED’s Contractor

As above

C

1, 6

T

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

U

On-site separation

On-site separation of municipal solid waste and construction/demolition wastes shall be conducted in order to minimise the amount of solid waste to be disposed to landfill.

CED’s Contractor

As above

C

1, 11

V

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

W

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

X

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

 

 

 

 

 

AA

B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T U, V, W and X as above

Submit supplementary CAP and conduct additional sampling to determine more accurately the extent of contamination.  As above (see W for soil remediation).

CED’s Contractor

KTCDA work areas. Duration of the soil remediation

R

As above

BB

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 any other parameters to be agreed with EPD prior to any consent being given to discharge.

CED’s Contractor

As above

 

5

CC

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

 

1, 10

4

Monitoring and Audit

To be carried out in accordance with the Schedule in the EM&A Manual.

CED*/ Contractor/ RSS

KTCDA 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)

@             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 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


9.                  Conclusions and Recommendations

9.1              Introduction

9.1.1          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 have been proposed.  The mitigation measures proposed to control noise, and dust impacts in the demolition phase should be carried forward to the decontamination phase.

9.1.2          The demolition of a municipal incinerator constitutes a designated project under the provisions of the Environmental Impact Assessment Ordinance (EIAO).  Kennedy Town Comprehensive Development Area (KTCDA) includes the Kennedy Town Incineration Plant (KTIP) and an animal cremator at Kennedy Town Abattoir (KTA).  A study brief (ESB023/98) for the EIA of the demolition of KTCDA was issued by EPD under the EIAO in December 1998.  CED subsequently compiled a full Study Brief (SB) for consultants to follow for this Study (Environmental Impact Assessment for the Demolition of the KTCDA as part of Agreement No. CE 15/99) which includes the requirements of ESB023/98.

9.2              Demolition Methodology

9.2.1          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 Appendix A).  Blasting methods were ruled out and the summary of the Preferred Demolition Methodology presented was that non-explosive demolition methods should be used for the demolition of Kennedy Town Comprehensive Development Area.

9.3              Asbestos

9.3.1          The operation of the elements within the KTCDA has not given rise to any residual contamination with asbestos containing materials (ACM) dust or fibre.  However there are some remaining ACMs which will require removal before the buildings and chimneys 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.  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).  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. 

9.3.2          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.  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 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.  Whereas it is not expected that asbestos fibre would be liberated from the asbestos abatement works, EM&A for asbestos fibre has been conducted at the boundary on Government sites and this is recommended at the Site boundary for reassurance purposes.

9.4              Land Contamination and Remediation

9.4.1          The presented contamination assessment is based on the results of a detailed Site Investigation, including the collection of sub-surface samples and followed by chemical analyses.  This has indicated that remediation is required at the majority of borehole locations in accordance with current Government policy. A Remediation Action Plan has therefore 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 KTCDA are relatively low, provided appropriate precautions are implemented.  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.

9.5              Noise

9.5.1          Noise impacts will require mitigation and recommendations on EM&A procedures at selected NSRs are made.  The assessment has assumed a worst possible case and that the use of pneumatic breakers and other hand held equipment will be widespread.  The use of silenced equipment, portable barriers and controls on the operating times of plant will be sufficient to control noise to acceptable levels.  However these recommendations shall not rule out the use of other more environmentally friendly (quieter) techniques where these are practicable.  It is recommended that the selection of non-blasting demolition techniques identified in the DCDB shall be made at the detailed design stage to minimise noise and vibration. EPD recommendations (Practical Guide to Reduction of Noise from Construction Works) for the use of portable noise barriers to allow noise attenuation wherever practicable and the implementation of these recommendations through the environmental monitoring and audit programme will bring the noise well within acceptable levels.

9.6              Air Quality

9.6.1          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 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 to ensure that the dust criteria will not be exceeded.  Whereas it is not expected that asbestos fibre would be liberated from the asbestos abatement works, EM&A for asbestos fibre has been conducted at the boundary on Government sites and this is recommended at the Site boundary, however this is for reassurance.

9.7              Waste Management.

9.7.1          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 in accordance with the Waste Disposal Ordinance (Cap 354), Waste Disposal (Chemical Waste) (General) Regulation and the Government Land Ordinance (Cap 28) and collection of general refuse and general Site housekeeping should be carried out.  Disposed 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 KTCDA will be in full compliance with the regulatory requirements.

9.8              Environmental Monitoring and Audit.

9.8.1          The Proponent will appoint an environmental professional acceptable to EPD to design, implement and supervise the EM&A works.  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.

 


 

Appendix A

 

 

          Preferred Demolition Methodology


Attachment 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

CSTG

Cadogan Street Temporary Garden

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

KTA

Kennedy Town Abattoir

KTCDA

Kennedy Town Comprehensive Development Area

KTIP

Kennedy Town Incineration Plant

LDC

Land Development Corporation

LGHAGN

Landfill Gas Hazard Assessment Guidance Note

MTIA

Marine Traffic Impact Assessment

NWFB

New World First Bus Depot

PCWA

Public Cargo Working Area

PFBP

Public Fill Barging Point

PQA

Preliminary Quantitative Assessment

RAC

Registered Asbestos Consultant

R7

Route 7

RCP

Refuse Collection Point

RSE

Resident Site Engineer

SR

Sensitive Receiver

TIA

Traffic Impact Assessment

TM

Technical Memorandum

USD

Urban Services Department

 


 

SUMMARY

I.                     The contents of this Attachment A to the EIA for the Demolition of the Kennedy Town Comprehensive Development Area was originally presented to Government Departments.  The contents of this paper was endorsed at the First Study Management Group Meeting for the study Environmental Impact Assessment Study for Demolition of Kwai Chung Incineration Plant and Kennedy Town Comprehensive Development Area, CE 15/99. 

II.                   The preferred demolition methods were endorsed as a basis for defining the activities to be addressed within the environmental impact assessment and the analysis of the alternative demolition options and the major conclusions regarding demolition methods are presented.  The Working Paper also presents the major constraints associated with the Projects.   For purposes of presenting supporting material to the EIA for the Demolition of the Kennedy Town Comprehensive Development Area the text referring to Kwai Chung Incineration Plant has been deleted.

III.                 The PPFS for KTCDA concluded that the preferred method of demolition was by traditional top down methods utilising manual tools and mechanical plant but that the possibility of demolition by implosion for two chimneys (one at the incineration plant and one at the abattoir) could not be ruled out.  The PPFS recommended that the feasibility of demolition of the chimneys by implosion or other unconventional techniques be further investigated in the EIA.

IV.                 Consultation with Government Departments has confirmed the concerns regarding implosive demolition identified in the PPFS for KTCDA and the preference for top down demolition methods.  Investigations have shown that ACM is present in the abattoir chimney and the incinerator chimneys and at other location in the KTCDA.  The weather cladding of the KTIP buildings is also ACM.  This dictates that a non-blasting approach is required in order that the ACM can be removed in line with statutory requirements.

V.                   The KTCDA is surrounded by residential development and other sensitive uses.  The risks, hidden costs and knock on effects of implementing any proposal which includes blasting techniques for the felling of the chimneys or the main building structures also makes such options unattractive.

VI.                 The details of the constraints to demolition are presented and 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.

VII.               The conclusion is that non-explosive demolition methods should be used for the demolition of the Kennedy Town Comprehensive Development Area.


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 Kennedy Town Incineration Plant (KTIP) is within the boundary of the KTCDA and ceased to operate March 1993 and has been decommissioned and the facilities require demolition. The demolition of the remaining facilities 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 that must be considered in the final demolition process.  The paper presents information that facilitated decisions on acceptable conceptual demolition methods for both 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 3        General Approach to Demolition of Buildings and Structures.

·         Section 4        Conceptual Demolition Method for Chimneys at KTCDA.

·         Section 5        Conclusions.


A2.          Project and Study Area

A2.1       Kennedy Town Comprehensive Development Area (KTCDA)

A2.1.1     The proposed Kennedy Town Comprehensive Development Area (KTCDA) is situated next to Victoria Road and Cadogan Street, Kennedy Town, and adjacent to Victoria Harbour, with a site area of about 34,000 square metres.

A2.1.2     The KTCDA comprises several elements as well as the Kennedy Town Incineration Plant (KTIP).  The main operations at the Kennedy Town Abattoir (KTA) ceased and relocated to new facilities at Sheung Shui in the autumn of 1999.  The KTA includes an incinerator for disposal of animal carcasses and waste that is managed by EPD.  The KTA plant remains in place.

A2.1.3     Part of the former EMSD Depot that forms part of the KTCDA has been leased to New World First Bus (NWFB) for bus maintenance and refuelling, under a short-term tenancy.  The remainder is leased as a car / lorry park.  These facilities will remain in operation for the time being.

A2.1.4     The former Kennedy Town Wholesale Market has been relocated and this area has been remodelled as a park and sitting out area adjacent to Victoria Road.  This is known as the Cadogan Street Temporary Garden (CSTG).

A2.1.5     Food and Environmental Hygiene Department have recently constructed a Refuse Collection Point (RCP) between the park and the Abattoir at Sai See Street.

A2.1.6     The KTCDA includes:

·         the Kennedy Town Incineration Plant (KTIP);

·         the Kennedy Town Abattoir (KTA);

·         the New World First Bus Depot (NWFB);

·         car / lorry park (CP);

·         FEHD Refuse Collection Point (RCP); and

·         the Cadogan St Temporary Garden (CSTG).

A2.1.7     The structures to be demolished are summarised in Table A2.1.

A2.1.8     The KTCDA was recommended for future private housing development in the “Planning and Engineering Study for the Redevelopment of Mount Davis Cottage Area and Kennedy Town Police Married Quarters” (Agreement No. CE 52/97), completed in May1999.  The Open Space and Refuse Collection Point were proposed to be permanently relocated within the redevelopment.

A2.1.9     The proposed Green Island Reclamation and Route 7 (R7), a strategic road link between Kennedy Town and Aberdeen, are located just to the north of the KTCDA site although the exact alignment of R7 is not yet confirmed.  A further planning and engineering study to address some major issues, including the Green Island Development and alternative road alignments of Route 7, is currently being considered by the government.  The findings from this further study may alter the future land use of the KTCDA.

Table A2.1            Structures to be demolished at KTCDA

Building

Brief Description

KTIP Chimneys

Two reinforced concrete chimneys, 60m high, 3.5m in diameter.

KTIP Building

Reinforced concrete structure of approximately 3,025m² on plan,

Refuse Pier

Kennedy Town Abattoir

5-storey reinforced concrete structures of approximately 9,500m² on plan,

Reception Pier

Former EMSD Building

Boiler House and Animal Carcass Incinerator Building.

One reinforced concrete chimney, 25m high, 3m in diameter.

New World First Bus Depot

Offices and Vehicle Inspection Bays. Overall size is approximately 600m² on plan.

Hong Kong Electric Sub Station

Single Storey Transformer House (adjacent to KTA lairage)

Cadogan Street Temporary Garden

(Inclusion / Exclusion / Programme Requires Decision.)

Sai See Street Refuse Collection Point

(Inclusion / Exclusion / Programme Requires Decision.)


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.

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 2002 with demolition works lasting about one year.

A3.2       Sensitive Receivers at KTCDA

Residential, Government, Institutional and Community

A3.2.1     Residential, Government, Institutional and Community uses surround the KTCDA site and many are elevated and overlook the site.  The nearest rank of sensitive receivers is discussed below.

·         Kennedy Town Police Married Quarters currently overlooks the site.  The premises are scheduled to be vacated but parts of the buildings will potentially be occupied up to March 2002.

·         The Mount Davis Cottage Area has already been partially vacated and the remaining premises will be vacated up to March 2001.

·         The new Housing Society development at Ka Wai Man Road is scheduled for occupation by mid 2000.

·         There are occupied residential building at Cadogan Street including Centenary Mansion.

A3.2.2     Other premises in the low rise blocks at Cadogan Street are scheduled for demolition in preparation for the Land Development Corporation’s urban renewal project.  Whereas many of the ground floor commercial premises remain in operation temporarily, the residential units above have been vacated or are scheduled to be vacated by the time demolition of KTCDA takes place.

A3.2.3     Manhattan Heights high rise development at Kennedy Town New Praya overlooks the site. Residential units will be occupied by the time demolition of KTCDA takes place.

A3.2.4     There are Government, Institutional and Community uses at St Lukes Church School, St Lukes Settlement, Jockey Club Clinic, Victoria Mortuary and the Bayanihan Centre.

A3.2.5     St Lukes Church School on Ka Wai Man Road and the, St Lukes Settlement and Jockey Club Clinic will remain in operation at the time of demolition for KTCDA.

A3.2.6     The Bayanihan Centre on Victoria Road is a training and support facility for Philippine overseas workers which is open seven days per week and it is assumed this will remain in operation at the time demolition of KTCDA takes place.

A3.3       Implications of Demolition by Implosion at KTCDA

A3.3.1     Non-explosive demolition methods used the EIA will lead to the recommendation recommend of a series of mitigation measures to protect the residential, government, institutional and community uses and all other sensitive receivers that surround the KTCDA.

A3.3.2     If explosive demolition methods were to be used, the EIA would include a comprehensive Risk Assessment Report covering the effects of the affected neighbourhood would be required.  The assessment would be undertaken within this Study and one of the results would be to recommend risk reduction measures to ensure that explosive demolition would be carried out within the Hong Kong Risk Guidelines.  These requirements would be included in the Environmental Permit.

A3.3.3     One such likely requirement is the inclusion of an exclusion zone to minimise the chance of ejecta or debris hitting any spectators.  Whereas the exclusion zone cannot be determined at this stage, it is possible to identify the likely size of such a zone by reference to other studies.  Recent requirements for the minimisation of risks from ejecta, included in the Environmental Permit (EP-002/1998) for the Felling of Five Power Station Chimneys at Tsing Yi Power Station Chimneys by explosion, included an exclusion zone equivalent to three times the chimney heights.

A3.3.4     The “Draft Code of Practice for Demolition of Buildings (Buildings Department) requires that all residents or inhabitants within an exclusion zone be evacuated during blasting.  The radius of a typical exclusion zone is not less than 2.5 times the height of the structure to be demolished.  The highest structures at the KTCDA are the KTIP chimneys at 60m.  Experience therefore suggests that an exclusion zone of two and a half (150m) to three times (180m) the height of the structures to be demolished would be required at the KTCDA.  The possible limits of exclusion with respect to the chimneys at KTCDA are shown on Figure 2.1.

A3.3.5     The PPFS for the demolition of KTCDA noted that, due the short distance between Chimney “A” and other buildings to the west, it would be a high risk option to demolish using explosives.  The PPFS also noted that the possibility of demolition of Chimneys B and C using explosives could not be ruled out at that stage.  However the PPFS did not make reference to any other buildings in the vicinity.  The Kennedy Town Police Married Quarters, St Lukes Settlement, Jockey Club Clinic, Victoria Mortuary, Bayanihan Centre, St Lukes Church School, Hosing Society Residential Development, Cadogan Street Temporary Garden, China Merchants Wharf, Industrial Buildings in Victoria Road and Public Piers at Cadogan Street would all be within a 2.5 times exclusion zone for evacuation for Chimney “B”.

A3.3.6     The PPFS report also notes that the Cadogan Street Temporary Garden (GLA-THK 10550), RCP (GLA-THK 1054) and the New World First Bus Depot are subject to leases requiring one month notice for termination.  The FEHD RCP at Sai See Street is subject to a lease requiring three months notice for termination.  The reprovision of the Cadogan Street Temporary Garden and the Temporary RCP have been planned to be within the Kennedy Town CDA redevelopment.  The location for an alternative site for the New World First Bus Depot has been proposed to lie within the Green Island Development.  In the event that these locations cannot be closed for operational reasons, they may also have to be temporarily closed or evacuated during demolition by implosion, if they are not already handed back to Government by the time of demolition.

A3.3.7     USD have indicated that there is no programme identified to relocate the newly developed RCP and CSTG.  Whereas these sites would require protection during the demolition, regardless of the demolition method, there would be more opportunity for a flexible approach to the phasing of demolition if non-blasting methods are used and exclusion zones are not required.

A3.3.8     The New World First Bus Depot also includes diesel fuel storage tanks and other lubrication oil storage.  Experience also suggests that such tanks in reasonably close proximity to demolitions by implosion would be required to be emptied and sterilised for the duration of the felling by implosion in order to reduce risk.

A3.4       Other Sensitivities near KTCDA

Road Traffic

A3.4.1     Road traffic access must be maintained for residential and commercial uses at Kennedy Town.  There are general concerns about the potential impact of traffic to and from the demolition site on the local network.

A3.4.2     Access must be maintained for commercial uses at China Merchants Wharf and Godowns, the Kennedy Town public transport terminus Victoria Public Mortuary, industrial buildings, residences on Victoria Road, the petrol station on Victoria Road and the Island West Refuse Transfer Station.

A3.4.3     Whereas the exact volume of waste to be disposed of has not yet been determined, preliminary estimates indicate that 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.  Traffic Impact Assessments carried out for the “Planning and Engineering Study for the Redevelopment of Mount Davis Cottage Area and Kennedy Town Police Married Quarters” (Agreement No. CE 52/97) indicate that this level of additional traffic could be absorbed into the surrounding network without significant impacts.

A3.4.4     In addition the impact of potential road closures needed to allow blasting techniques, such an approach would require additional studies which are outside of the Brief and may delay the EIA programme.  Transport Department have indicated a general presumption that a road closure would be unacceptable unless it can be proven that traffic impacts can be mitigated to acceptable levels.  A full traffic impact assessment (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 be required.

Marine Traffic

A3.4.5     Access must be maintained for vessels accessing the pier at China Merchants Wharf and Cadogan Street and interference to the Victoria Harbour marine traffic must be minimised.  Although local assessments indicate that additional waste disposal vehicles could be absorbed into the surrounding road network, it has been suggested that barges could be used to remove waste in order to reduce overall road traffic impacts.  Such a proposal may also require a Marine Traffic Impact Assessments (MTIA).

A3.4.6     The exclusion zone for blasting would also be applied to marine vessels in the area and together with the requirement to evacuate the China Merchants Wharf and Godown, this may require compensation to the operators and the hidden cost organising and patrolling such an evacuation in the busy harbour.

Weather

A3.4.7     The KTCDA is close to the slopes of Mt. Davis which have been prone to landslides in the past.  Blasting restrictions may be necessary and initiation of blasts may need to be prevented following periods of heavy rain as this may increase the likelihood and effect distance of landsides.  Likewise blasting demolition would not be allowed in periods of high or gusting winds to avoid the possibility of chimneys falling in unplanned directions or at an unplanned time.  Both considerations introduce uncertainty to the programme but in particular add to the difficulties in co-ordination of evacuation of the exclusion zone.

Other Issues

A3.4.8     The revised alignment for Route 7 and extent of the Green Island Developments are currently under review but at present the programme of these developments is unlikely to be advanced before 2002 and after the target completion date for demolition of KTCDA.  These development proposals should therefore have no impact on the Project.

A3.5       Implications of the Presence of Asbestos Containing Materials

A3.5.1     An Asbestos Investigation Report (AIR) and Asbestos Abatement Plan 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     Records show that bulk asbestos removals of ACM from the KTIP was undertaken prior to the removal of main plant and machinery some years ago.  Site surveys and inspection of the plans for the KTA suggest that asbestos containing materials (ACM) are present in the chimney of the KTA.  Drawings indicate that an asbestos rope was used to seal joints between the sections of the chimney.  Such materials may only be accessible as the sections of the chimney are dismantled.  Blasting could result in the uncontrolled release of asbestos fibre.  Therefore blasting will not be an option.  Other areas which will require investigation but which have to date not been accessed include the insulation to the carcass incinerator, the blood boilers and chimney duct insulation.  However, the presence of ACM in these locations will not have a significant bearing on the choice of demolition method as they can be removed as soon as the relevant plant is decommissioned.

A3.5.4     Investigations have confirmed the presence of a typical low risk asbestos containing material (ACM) on the superstructures of the KTIP incinerator building.  This is in the form of corrugated metal weather cladding with an asbestos type mastic protective paint coating.  This is identical to ACM typically found at other industrial sites in Hong Kong, built in the 1960s and 1970s.   Other ACM has also been identified at KTIP.

A3.5.5     Site visits did not reveal any potential ACM in the New World Bus Depot or the other parts of the Site.  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 approach for the demolition of Kennedy Town Comprehensive Development Area.


A4.          General Approach to Demolition of Buildings and Structures at KTCDA

A4.1       General Approach

A4.1.1     This section seeks to illustrate some of the more general procedures for demolition that would apply to KTCDA.  The intention in this and section 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 Environmental Impact Assessment.

A4.1.2     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 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 indicated.  The options selected are also broadly in line with the Draft Code of Practice for Demolition of Buildings (Buildings Department 1998) which will also need to be observed at the detailed design stage.

A4.1.3     The overriding concerns for the demolition Projects 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 site 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 preferable on a daily basis and stockpiles should not be allowed to build up.  In general it is anticipated that demolition waste would be removed on a daily basis with several tens of lorries leaving either 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, unauthorised 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 KTCDA

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 authorised 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 (i.e. say 10meters from ground level or greater) is that the chimneys will be broken into small pieces on the spot by operatives using hand held tools.  They would work from working platforms external to the chimney (Figure 5.1).  Hydraulic breakers would be used for the remaining lower portions of the chimneys.

A5.2.2     Prior to the commencement of the demolition work, loose sand will be placed on top of the existing ground around the chimneys to receive small pieces of light debris that may fall.  To facilitate the access of the excavators for the removal of debris, an access ramp will be formed.  The vertical opening (former fan duct connection point) near the base of the stack would be blocked when demolition is in progress.  This portal would be opened for removal of debris after completion of daily demolition work.  The above mentioned method of removal of debris is only applicable to the demolition of the upper portion of the chimneys.

A5.2.3     For demolition of the lower portion, 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.

A5.2.4     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.

A5.3       Preparation

A5.3.1     The area surrounding the chimney will be secured and all necessary barricades erected.  Only authorised personnel will be allowed into the area.  A steel external working platform system will be erected to surround the upper portion of the chimney, i.e. greater than 10 meters above ground level.  The maximum distance between the floor levels of the working platforms will be two meters.  Access steel ladders will be constructed from ground level to the top of each chimney, with proper handrails (Figure 5.1).

A5.4       Sequence of Operations

A5.4.1     The demolition sequence would involve the construction of a series of working platforms around the outside of a chimney.  Workers would work from the top most platform to remove the chimney structure with the debris directed into the lower portion of the remaining chimney.  This would involve the following steps.

a)      All required preparation work and safety measures would be installed.  The area surrounding the chimney would be made secure and all necessary barricades erected.

b)      Safety netting and tarpaulins would be installed to enclose the location at which demolition work is in progress (i.e. the external boundary of the steel working platform from platform floor level to one meter above the top edge of the remaining chimney wall).  Checks would be made to ensure no gaps were present between floor boards and between the front edge of platform and the external surface of the chimney, so as to avoid falling of broken pieces out beyond the netted working platform.

c)      The portion of the wall from say 0.3m above the floor level of the working on the platform to the top of the chimney will be demolished by operatives working on the platform using hand held pneumatic breaking tools to break the existing chimney concrete into small pieces.  Work would proceed from top working towards the lower level.  The steel reinforcement exposed in the process would be cut by flame and lowered to ground.

d)      After completing the work at one level operatives would descend to the working platform just below and remove the components of the upper platform carefully.  Demolition at the lower platform level would then proceed safety nets will be installed in the same manner as described in procedure (b) above.

e)      The debris would be cleaned out from the platform daily (each evening) to avoid accumulation of debris.

f)       The same sequence of work from procedure (b) to (d) would be repeated until the chimney had been lowered down to approximately 10m chimney height, a level within the reach of mobile hydraulic breakers at ground level.  The lower portion will be removed by these means.

A5.5       Duration of Demolition

A5.5.1     The buildings and chimneys at KTCDA 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.

A5.5.2     The estimated time for the completion of these works included in the PPFS was 12months which would appear to be ample time for demolition based on the above methodology.


A6.          Conclusion

A6.1.1     This paper presented information concerning the difficulties associated with the demolition of the Kennedy Town Comprehensive Development Area (the Project).  In order to facilitate the progress the EIA process as a whole it is necessary to define the Projects in sufficient detail in line with the objectives of the Study.

A6.1.2     The primary aim of this paper is to establish a conceptual demolition method 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 the 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 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     The preferred demolition methodology presumes that a variety of top down methods would 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 use of jack-hammers and hydraulic breakers is efficient and noise and dust impacts can potentially be controlled by a range of mitigation measures (e.g. noise barriers, dust control) familiar to the construction industry in Hong Kong.  In addition 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 the preferred method of demolition must adopt non-explosive approach.  The asbestos investigation and abatement plans are described in detail in the dedicated Asbestos Study Report.

A6.1.5     In order to facilitate the progress of the Environmental Impact Assessment the consultants sought and gained endorsement of the content of this 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 shall adopt top-down, non-explosive methods for the demolition of Kennedy Town Comprehensive Development Area.



Attachment B

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 Characteristic Leachate Testing Procedure (TCLP) tests for TPH, PAH and BTEX contaminated materials have to be carried out according to the testing frequency and requirements as stipulated in EPD’s “Guidance Notes for Investigation and Remediation of Contaminated Sites.  Pre-treatment 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 Characteristic Leachate Testing Procedure (TCLP) tests for PCDD/PCDF contaminated materials have to be carried out with reference to the requirements as stipulated in EPD’s Guidance Notes for Investigation and Remediation of Contaminated Sites.  Pre-treatment is required to bring levels of PCDD/PCDF to below the TCLP limit of 1ppb PCDD/PCDF (TEQ), subject to TCLP confirmation at a frequency of 1 sample per 100 tonnes of 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 C

 

 

Water Quality Standards

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

AppC.gif


 

Appendix D

 

 

Hazards & Safety Requirements


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

·                     Groundwater / Soil 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       Groundwater Leachate

1.3.1     The reclamation under the site may exude leachate originating from soil which may be contaminated or toxic and the following rules should therefore be observed:

·                     If leachate has to be handled, or groundwater samples, ensure that the operatives wear protective clothing and gloves.  If any operatives come into contact with contaminated leachate, they 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 at work, he should report this immediately to his supervisor who will arrange for medical attention.

1.4       Site Safety Precautions

1.4.1     All operational and supervisory staff’s attention shall be drawn to the hazards of potentiall contaminated ground.

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

1.4.3     Confined spaces and excavation, where entry is required shall be treated as described under Section 1.5.

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

1.4.5     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.

1.4.6     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.

1.5       Working in Confined Spaces

1.5.1     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.

1.5.2     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

1.5.3     All persons entering a confined space shall have received appropriate training from authorised bodies.

1.5.4     All written safe working procedures and completed “Permit-To-Work Certificate” shall be kept in the site office.

 

 


Appendix E

 

 

Environmental Outcome Profile

 


Environmental Outcome Profile

 

The Project

 

Total Project Cost :~HK$112 million

Cost of Environmental Component (EIA, Study and Mitigation Measures) say HK$31.0million.

 

Road works = N/A

Railway =N/A

Reclamation / dredging =N/A 

Power station =N/A

Drainage work =N/A

Development Study = N/A

Others: Demolition

 

a)      Demolition of the Main Plant Kennedy Town Incineration Plant Building (60m x 70m x 30m high) office building, loading jetty and refuse pier;

b)      Demolition of two 60m high chimneys and a 25m high chimney;

c)      Demolition of Kennedy Town Abattoir and cattle reception pier;

d)      Demolition of former EMSD Depot; and

e)      Ground remediation.

 

EIAO Application Reference:

An application Reference (No. ESB-023/1998) 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 500m of the project boundary would contain a population of approximately 42,000.  In addition there would be workers accessing the work sites adjacent as well as occupants of the 10,000 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 42,000 within 500m of the project boundary would potentially be affected by cumulative dust.  Implementing effective and adequate dust suppression will include measures such as the dampimg 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 of non-blasting methods will avoid the need to evacuate several sites and temporary closure of major road traffic arteries in the vicinity.  Remediation of contaminated soil on site will avoid the use of valuable landfill space, ensure that the site is suitable for all possible future uses.

The use of dust mitigation measures will avoid nuisances for the adjacent sensitive receivers, work sites or vehicles on the highways.  Water quality impacts will be avoided by the treatment of surplus site run-off, groundwater etc.  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 the 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 unsightly and derelict buildings, decontamination of the soil underneath the site and removal of several tonnes of asbestos waste.

Others :            A Pre EIAO EMSG meeting was held in EPD’s offices on July 24, 2001.

 

 



[1] Site observations elsewhere have indicated that the noise nuisance caused by the demolition process using hydraulic crushers was minimal.  Thus it is recommended that the use of hydraulic crushers should be considered as quieter alternative demolition methods.  This alternative would be 15 to 20 dB(A) quieter than a conventional hydraulic breaker.  Assuming the sound power level of hydraulic crusher is 107 dB(A), it has been calculated that four hydraulic crushers could be deployed without exceeding the appropriate criteria.   However hydraulic crushers are relatively new to the local construction industry and efficiency is recorded as 50% lower than that of a conventional hydraulic breaker.