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

 

 

 

 

 

 

 

EM&A Manual

 

 

 

September 2001

 

 

 

 

 

 

 

 

 

 

Atkins China Ltd

 


 

DOCUMENT TITLE PAGE

 

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-OR028-04

 

 

 

Controlled Copy No. :

 

           

 

Document Title :  EM&A Manual KTCDA

 

 

 

Covering Letter / Transmittal Ref. No. :

                           2996/15.109/ELT           /DG/OG

 

 

Date of Issue :

    September 2001

 

Revision, Review and Approval/Authorisation Records

 

 

/

/

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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/

DG/

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

 

 

 


CONTENTS

1.     INTRODUCTION.. 1-1

1.1       Purpose of the Manual. 1-1

1.2       Requirements for EM&A Programme. 1-1

1.3       Project Description.. 1-2

1.4       Sensitive Receivers and Constraints to Demolition.. 1-3

1.5       General Approach to Demolition of Buildings and Structures at KTCDA.. 1-4

1.6       Principles of Chimney Demolition at KTCDA.. 1-5

1.7       Remedial Action Plan for Contaminated Soils. 1-5

1.8       Environmental Study Requirements. 1-5

1.9       Project Organisation.. 1-5

1.10      Demolition Programme. 1-6

2.     AIR QUALITY.. 2-1

2.1       Air Quality Parameters. 2-1

2.2       Total Suspended Particulates. 2-1

2.3       Monitoring Equipment.. 2-1

2.4       Laboratory Measurement/ Analysis. 2-2

2.5       Dust Sensitive Receivers and Monitoring Locations. 2-2

2.6       Baseline Monitoring. 2-4

2.7       Impact Monitoring. 2-4

2.8       Event and Action Plan for Air Quality.. 2-5

2.9       Dust Mitigation Measures. 2-7

3.     Noise. 3-1

3.2       Noise Parameters. 3-1

3.3       Monitoring Equipment.. 3-1

3.4       Monitoring Locations. 3-1

3.5       Baseline Monitoring. 3-2

3.6       Impact Monitoring. 3-2

3.7       Event and Action Plan for Noise. 3-3

3.8       Noise Mitigation Measures. 3-3

4.     Water Quality.. 4-1

4.1       Sources of Water Quality Impacts. 4-1

4.2       Sewage Effluents. 4-1

4.3       Site Run-off and Surface Water Drainage during Demolition.. 4-1

4.4       Site Run-off and Surface Water Drainage during Soil Remediation.. 4-2

4.5       Conclusions. 4-3

5.     Waste Management.. 5-1

5.2       Mitigation Measures. 5-1

5.3       Waste Management Requirements. 5-5

6.     Contaminated Land.. 6-1

6.1       Remediation Action Plan.. 6-1

6.2       Mitigation Measures. 6-1

6.3       Protection of Site Workers during excavation and treatment of soils. 6-2

7.     Site Environmental Audit.. 7-1

7.1       Site Inspections. 7-1

7.2       Compliance with Legal and Contractual Requirements. 7-1

7.3       Environmental Complaints. 7-2

8.     REPORTING.. 8-1

8.1       General. 8-1

8.2       Baseline Monitoring Report.. 8-1

8.3       Monthly EM&A Reports. 8-1

8.4       Contamination Remediation Report.. 8-3

8.5       Data Keeping. 8-3

8.6       Interim Notifications of Environmental Quality Limit Exceedances. 8-4

9.     Schedule Mitigation Measures from the eia.. 9-1

 

List of Appendix

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

Appendix B             Role Of Independent Checker (Environmental) IC(E)

Appendix C             Water Quality Standards

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

Appendix E             Site Safety Precautions

 

 

List of Tables

Table 1.1      Structures to be demolished at KTCDA   1-2

Table 1.1      Structures to be demolished at KTCDA   1-7

Table 2.1      Action and Limit Levels for Air Quality   2-5

Table 2.2      Event/Action Plan for Air Quality   2-6

Table 2.3      Data Sheet for TSP Monitoring   2-8

Table 3.1      Action and Limit Levels for Construction Noise  3-3

Table 3.3      Noise Monitoring Field Record Sheet   3-5

Table 5.1      Summary of Waste Management Impacts   5-1

Table 6.1      Actions Required Post Demolition   6-3

Table 7.1      Event Contingency Plan for Environmental Complaints   7-3

Table 8.1      Sample Template for Interim Notifications of Environmental Quality Limits Exceedances   8-4

Table 9.1      Schedule of Impacts and Mitigation Measures   9-1

 

List of Figures

Figure 1.1         Kennedy Town CDA Locality Plan

Figure 1.2         Typical Perimeter Noise Barrier

Figure 1.3         EM&A Management Structure

Figure 2.1         Proposed Dust Monitoring Locations

Figure 2.2         Proposed Airborne Fibre Monitoring Locations

Figure 3.1         Proposed Noise Monitoring Locations

Figure 6.1         KTCDA Borehole Contaminated Location Requiring Clean Up

Figure 6.2         Principles of Remedial Action Plan

 


 

LIST OF Abbreviations

AL                   Action/limit

BC                   Bayanihan Centre

CNP                 Construction Noise Permit

EM & A           Environmental Monitoring and Audit

EPD                 Environmental Protection Department

ER                   Engineer’s Representative

ET                    Environmental Monitoring Team

ETL                 Independent Environmental Monitoring Team Leader

EWC                Environmental Works Checker

HKWDS          Hong Kong Island West Development Statement

HVS                 High Volume Sampler

HyD                 Highways Department

IC(E)                Independent Checker (Environment)

IWRTS             Island West Refuse Transfer Station

JCC                  Jockey Club Clinic

KTCDA           Kennedy Town CDA Site

KTPMQ           Kennedy Town Police Married Quarters

LAR                 Lantau Airport Railway

MDCA             Mount Davis Cottage Area

NCO                Noise Control Ordinance

NSR                 Noise Sensitive Receiver

SIS                   Singapore International School

SR                    Sensitive Receiver

TDSR               Territorial Development Strategy Review

TM                   Technical Memorandum

TSP                  Total Suspended Particulates

USAEPA         United States of America Environmental Protection Agency

 


1.                   INTRODUCTION

1.1              Purpose of the Manual

1.1.1          The purpose of this Environmental Monitoring & Audit (EM&A) Manual is to guide the EM&A programme for the Demolition of Buildings and Structures within the Proposed Kennedy Town Comprehensive Development Area (KTCDA study brief ESB-023/98) and to ensure compliance with the Environmental Impact Assessment (EIA) Report.  This is subject to approval of the EIA Report under the statutory procedures of the EIAO and supporting Technical Memorandum.  The EIA recommends procedures to:

·         Ensure that any environmental impacts resulting from the demolition of the KTCDA are minimised or kept to acceptable levels.

·         Check that mitigation measures have been applied and are effective, and that the appropriate corrective actions are undertaken, if and when required.

·         Provide a means of checking compliance with environmental objectives, recording anomalies and documenting corrective action.

1.1.2          This Manual contains the following:

·         Information on the KTCDA demolition project, the project organisation and construction programme;

·         General EM&A principles and the EM&A team organisation;

·         Monitoring parameters, schedules, Action/Limit Levels and action plans;

·         Complaints procedures.

·         Reporting procedures.

1.1.3          As a general note the IC(E) may be part of the Engineer’s Team, or may be totally independent, employed under a separate contract by the project proponent.  In the latter case, this Manual makes reference to items requiring agreement between the Contractor (or his monitoring team), the engineers representative, relevant Government departments and the IC(E). Attention is drawn to the possibility of requiring agreement from a third party outside the contract in the event that the IC(E) is employed independently.

1.2              Requirements for EM&A Programme

1.2.1          The Criteria for undertaking EM&A are provided by EPD, these are summarised as follows:

(a)    to protect sensitive receivers from environmental impacts if mitigation is not implemented;

(b)    to protect the ecosystem;

(c)    to monitor activities in areas of high conservation value;

(d)    to monitor the effectiveness of mitigation measures which involves a long period to establish;

(e)    to monitor any unproven technology;

(f)     to validate the hypothesis in analysis and design;

(g)    to audit the changing project scheduling; and

(h)    others.

1.2.2          The conclusions from the EIA indicate that Criterion a) is relevant with respect to the possible impact excessive dust and noise may have on the sensitive receivers in close proximity to the KTCDA.

1.2.3          Without mitigation for dust and noise during the demolition phase, activities could cause nuisance to the residents or occupants of the residential and some GI/C facilities in the immediate vicinity.  The other criteria are not relevant to this project.  On the basis of this interpretation of Criterion a) an EM&A programme is recommended.

1.3              Project Description

1.3.1          The endorsed preferred method of demolition shall adopt a top-down, non-blasting approach for the demolition of KTCDA.  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);

·         FEHD Refuse Collection Point (RCP); and

·         Cadogan Street Temporary Garden (CSTG).

1.3.2          The structures to be demolished are summarised in Table 1.1.

1.3.3          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.

1.3.4          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 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 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 recommended in May 1999.

Table 1.1         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 store.

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.

1.3.5          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 2003 with demolition works lasting about one year.  Soil remediation may take another six to eight months.

1.4              Sensitive Receivers and Constraints to Demolition

1.4.1          This section identifies the sensitive receivers (SRs) affected by the Project as defined in the EIAO and summarises the main implications of the SRs and infrastructure on demolition methods.  Sensitive receivers and other constraints are shown in Figure 1.1.

Sensitive Receivers at KTCDA

Residential, Government, Institutional and Community

1.4.2          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 already been vacated.

·         The new Housing Society development (Cayman Rise) at Ka Wai Man Road is scheduled for occupation by the 3rd quarter of 2001.

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

1.4.3          Other premises in the low rise blocks in Cadogan Street (north of Victoria Road) haven been demolished.

1.4.4          Manhattan Heights high rise development at Kennedy Town New Praya and some of the residential units will overlook the site by the time demolition of KTCDA takes place.

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

1.4.6          There are Government, Institutional and Community uses at St Lukes Church School, St Lukes Settlement, Jockey Club Clinic, Victoria Mortuary and the Bayanihan Centre.  St Lukes Church School on Ka Wai Man Road and both St Lukes Settlement and Jockey Club Clinic will remain in operation at the time of demolition for KTCDA.  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.

NWFB and RCP

1.4.7          The New World First Bus Depot and the Refuse Collection Point may require relocation prior to the demolition.  However this is not material to the EIA as neither are defined as SRs. Road Traffic

Other Issues

1.4.8          The revised alignment for Route 7 and the extent of the Kennedy Town Development are currently under review but at present the programme of these developments is unlikely to be advanced before year 2002 and after the target completion date for demolition of KTCDA.  At this stage these proposals are not thought to have any impact on the Project.

1.4.9          Based on initial site investigations and according to the building drawings for the Sites records, some asbestos containing materials (ACM) are present at KTCDA. The asbestos investigation and abatement plans are described in detail in the dedicated Asbestos Study Report.  Asbestos abatement will take place in line with the requirements of the APCO and codes of practice.

1.5              General Approach to Demolition of Buildings and Structures at KTCDA

General Approach

1.5.1          This section presents general procedures for demolition, which would be likely to apply to KTCDA to illustrate the agreed methodology which has been used to progress the Environmental Impact Assessment.

1.5.2          Whereas the eventual detailed demolition plan of the selected demolition Contractor(s) may not necessarily adopt the precise methodology proposed in WP1 and summarised here, the consultants believe that general characteristics of the methods are appropriate.  Blasting will not be used and other conventional methods are sufficiently effective and applicable for the tasks.  Where possible methods that will help reduce noise and dust nuisances have been chosen.  The options selected are also broadly in line with the Draft Code of Practice for Demolition of Buildings (Buildings Department 1998) which will also need to be observed at the detailed design stage.

1.5.3          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

1.5.4          The typical site hoarding will be modified in to a perimeter noise barrier as shown in Figure 1.2.  Portable barricades will be used to cordon off different work zones within the site.  All structures are totally within the proposed Project sites and access would be controlled by security guards.  No members of the public or unauthorised person would be allowed entry to the site.  Only Contractors’ personnel and Government officials would be allowed within the Contractor’s working area.

General Demolition Principles

1.5.5          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-loading bearing cladding 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.

General Safety Measures

1.5.6          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.

1.5.7          The Contractor shall arrange for a competent scaffolder to visit site and inspect the scaffolding work, and to make any adjustments as the work proceeds, to ensure its stability.

1.5.8          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.

1.5.9          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.

1.6              Principles of Chimney Demolition at KTCDA

General Approach

1.6.1          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.

1.6.2          The concrete weather shield and the flues will be removed manually.  The principle of the demolition procedure shall be that the chimney and flues would be cut into pieces and these pieces lowered 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.

1.6.3          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.  Hydraulic breakers would be used for the remaining lower portions of the chimneys.

1.7              Remedial Action Plan for Contaminated Soils

1.7.1          The areas requiring decontamination, identified based on the Contamination Assessment Report and Remediation Action Plan are shown in Figure 6.1. 

1.8              Environmental Study Requirements

1.8.1          The EIA recommended a range of mitigation measures to control the demolition Project’s potential construction environmental impacts, which include dust and noise impacts.  The schedule of mitigation measures is provided in Section 7 of this Manual.

1.9              Project Organisation

1.9.1          The proposed project organisation is presented in Figure 1.3 as the basis of information available at the time of report preparation.

1.9.2          The preferred approach is for the Independent Environmental Monitoring Team (ET) to be employed directly by the project proponent (CED).  The monitoring is audited and checked by the Environmental Monitoring Team Leader (ETL) who reports to the Engineer’s Representative (ER).

1.9.3          Independent Monitoring Team Leader (ETL): This person should be professionally qualified with suitable experience in environmental management and planning.  As a general recommendation, 7 years’ experience is desirable, although if the proposed ETL has less, agreement should be sought from the ER.  Extensive knowledge of the study area is required.  The ETL should have work experience in Hong Kong managing and providing specialist advice on environmental monitoring of infrastructure projects.

1.9.4          Site Inspection Team Leader: Requires experience working on environmental projects in Hong Kong. Extensive experience in dealing directly with Contractors is required.

1.9.5          Noise/Air Specialist: Requires experience in the air and noise pollution field. Skills in the use of computer models, database design and management of monitoring programmes are required.

1.9.6          Consultant: Experience as an environmental consultant with a broad range of expertise both in the technical and managerial aspects of environmental assessment.  Proficient in: water quality sampling, analysis and assessment; air and noise monitoring, modelling and analysis; site assessment; and scoping exercises to identify key environmental issues.

1.9.7          Assistant Consultant: Experience in conducting on-site monitoring, data-gathering and subsequent computer-modelling data analyses.

1.9.8          The duties to be undertaken by the Environmental Team (ET) comprise the following:

·         sampling, analysis and statistical evaluation of monitoring parameters with reference to the EIA Study recommendations and requirements.

·         environmental site surveillance;

·         audit of compliance with environmental protection and pollution prevention and control regulations;

·         monitor the implementation of the environmental mitigation;

·         monitor compliance with the environmental protection clauses/specifications in the Contract;

·         review construction (demolition) programme and comment as necessary;

·         review construction (demolition) methodology and comments as necessary;

·         complaint investigation , evaluation and identification of corrective measures;

·         liaison with IC(E) on environmental performance matters and submission of EM&A deliverables to IC(E) for approval; and

·         advise on environmental improvement and enhancement.

1.9.9          Appropriate resources shall be allocated by the ET to fulfil the duties specified in this Manual.

1.9.10      Independent Checker (Environment).  The role of the IC(E) shall be independent from the management of construction works; but the IC(E) shall be empowered to audit the environmental performance of construction (Appendix B).  The IC(E) shall have a similar of level of experience as the ETL.

1.10          Demolition Programme

1.10.1      The structures to be demolished are summarised in Table 1.1.  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 2003 with demolition works lasting about one year.

1.10.2      The buildings and chimneys at KTCDA can be demolished and removed by conventional top down demolition using hand held tools and mechanical breaking methods.  Professional experience and consultation with local contractors indicates that the estimated time for the completion of these works of 12 months would appear to be ample time for demolition based on the above methodology.  The chimney demolition would follow demolition of the main buildings.  The EM&A programme will also cover the soil remediation phase, which will be undertaken following the demolition of structures which may last another six to eight months.

1.10.3      Whereas the demolition programme has yet to be established in detail, 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.  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.

Table 1.1         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 store.

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. *

           


2.                   AIR QUALITY

2.1              Air Quality Parameters

2.1.1          Monitoring and audit of Total Suspended Particulates (TSP) levels shall be carried out by the ET to ensure that any deteriorating air quality can be readily detected and timely action taken to rectify the situation.

2.2              Total Suspended Particulates

2.2.1          1-hour and 24-hour TSP levels shall be measured to indicate the impacts of construction dust on air quality.  The TSP levels shall be measured by following the standard high volume sampling method as set out in Title 40 of the American Code of Federal Regulations, Chapter 1 (Part 50), Appendix B.  Upon approval of the ER, 1-hour TSP levels shall alternatively be measured by direct reading methods to indicate short event impacts which are capable of producing comparable results as that obtained by the high volume sampling method.

2.2.2          All relevant data including temperature, pressure, weather conditions, elapsed-time meter reading for the start and stop of the sampler, identification and weight of the filter paper, and other special phenomena and work progress of the concerned site etc. shall be recorded in detail.  A sample data sheet is shown in Table 2.4.

2.3              Monitoring Equipment

2.3.1          High volume samplers (HVS) to be used for carrying out the 1-hr and 24-hr TSP monitoring shall comply with the following specifications:

·         0.6-1.7 m3/min (20-60 SCFM) adjustable flow range;

·         Equipped with a timing/control device with +/- 5 minutes accuracy for 24 hours operation;

·         Installed with elapsed-time meter with +/- 2 minutes accuracy for 24 hours operation;

·         Capable of providing a minimum exposed area of 406 cm2 (63 in2);

·         Flow control accuracy: +/- 2.5% deviation over 24-hr sampling period;

·         Equipped with a shelter to protect the filter and sampler;

·         Incorporated with an electronic mass flow rate controller or other equivalent devices;

·         Equipped with a flow recorder for continuous monitoring;

·         Provided with a peaked roof inlet;

·         Incorporated with a manometer;

·         Able to hold and seal the filter paper to the sampler housing at horizontal position;

·         Easy to change the filter; and

·         Capable of operating continuously for 24-hr period.

2.3.2          The ET shall provide sufficient equipment to ensure that the monitoring commences on schedule and is not interrupted as a result of equipment failure, damage, loss or routine maintenance.

2.3.3          The HVSs shall be equipped with an electronic mass flow controller and be calibrated against a traceable standard at regular intervals. All the equipment, calibration kit, filter papers, etc. shall be clearly labelled.

2.3.4          Initial calibration of dust monitoring equipment shall be conducted upon installation and thereafter at bi-monthly intervals.  The transfer standard shall be traceable to the internationally recognised primary standard and be calibrated annually. The calibration data shall be properly documented for future reference.  All the data shall be converted into standard temperature and pressure conditions.

2.3.5          The flow-rate of the sampler before and after the sampling exercise with the filter in position shall be verified to be constant and be recorded in the data sheet (Table 2.4).

2.3.6          If the ET uses a direct reading dust meter to measure 1-hr TSP levels, he shall submit sufficient information to the ER including calibration standards to demonstrate that the instrument is suitable for the monitoring task.  The instrument shall also be calibrated regularly, and the 1-hr sampling shall be determined periodically by HVS to check the validity and accuracy of the results measured by direct reading method.

2.3.7          The ET shall provide sufficient wind data monitoring equipment to ensure that the monitoring commences on schedule and is not interrupted as a result of equipment failure, damage, loss or routine maintenance.

2.4              Laboratory Measurement/ Analysis

2.4.1          A clean laboratory with constant temperature and humidity control, equipped with necessary measuring and conditioning instruments, to handle the dust samples collected, shall be available for sample analysis, equipment calibration and maintenance.

2.4.2          If a site laboratory is set up or a non-HOKLAS accredited laboratory is hired for carrying out the laboratory analysis, the laboratory equipment shall be approved by the ER and the measurement procedures shall be witnessed by the ER.  The ET shall provide the ER with one copy of Title 40 of the American Code of Federal Regulations, Chapter 1 (Part 50), Appendix B for his reference.

2.4.3          Filter paper of size 8”x10” shall be labelled before sampling. It shall be a clean filter paper with no folds or pin holes, and shall be conditioned in a humidity controlled chamber for over 24-hr and be pre-weighed before sampling.

2.4.4          After sampling, the filter paper loaded with dust shall be kept in a clean and tightly sealed plastic bag.  The filter paper will then be returned to the laboratory for reconditioning in the humidity control chamber followed by accurate weighing by an electronic balance to the nearest 0.1mg.  The balance shall be regularly calibrated against a traceable standard.

2.4.5          All the collected samples shall be retained and kept in a good condition for 6 months before disposal.

2.5              Dust Sensitive Receivers and Monitoring Locations

2.5.1          The dust sensitive receivers are shown in Figure 1.1.  These include the following:

Existing Sensitive Receivers:

·         Serene Court

·         Regent Heights Towers

·         Huncliffe Court

·         Cheong Kat Mansion

·         Centenary Mansion

·         Sai Wan Estate

·         Bayanihan Centre

·         Jockey Club Clinic (JCC)

·         St. Luke’s Church and Lui Ming Choi Memorial Primary School

·         Sai Wan New Apartments

·         Kennedy Mansion and

·         Cheong Kat Building

Future Receivers:

·         Future URA Development

·         Hong Kong Housing Society Residential Development (Cayman Rise)

·         Proposed Residential Development, Sai Wing Street

·         Manhattan Heights.

2.5.2          The status and locations of dust sensitive receivers may be revised after issue. The ET shall identify the SR locations to be adopted based on the updated construction programme and seek approval from the ER and relevant government departments.

Monitoring Locations

2.5.3          The monitoring locations should meet the following criteria:

·         A horizontal platform with appropriate support to secure the samplers against gusty wind shall be provided;

·         No two samplers shall be placed less than 2 metres apart;

·         The distance between the sampler and an obstacle, such as buildings, must be at least twice the height that the obstacle protrudes above the sampler;

·         A minimum of 2 metres of separation from walls, parapets and penthouses is required for rooftop samplers;

·         A minimum of 2 metre separation, measured horizontally, from any supporting structure, is required;

·         No furnace or incinerator flues shall be nearby;

·         Airflow around the sampler shall be unrestricted;

·         The sampler shall be more than 20 metres from the dripline;

·         Any wire fence and gate, to protect the sampler, shall not cause any obstruction during monitoring;

·         Permission must be obtained to set up the samplers and to obtain access to the monitoring stations; and

·         A secured supply of electricity will be needed to operate the samplers.

2.5.4          In general, monitoring should be undertaken at sensitive receivers.  However, as it cannot be guaranteed that permission to monitor at privately owned locations will be forthcoming (and hence to avoid delays in organising the monitoring programme and contractual difficulties), monitoring may be undertaken at alternative locations such as the site boundary, where necessary.  Suggested locations are shown on Figure 2.1. 

2.5.5          The criteria for locating samplers shall be as follows, as far as practicable:

·         take into consideration the prevailing meteorological conditions;

·        at the site boundary or such locations close to the major dust emission source; and

·        as close to the sensitive receivers as possible to reflect conditions at the sensitive receivers.

2.6              Baseline Monitoring

2.6.1          The ET shall carry out baseline monitoring as close as is practical to sensitive receivers as recommended above.  It is recommended that 2 locations are selected for baseline monitoring around the site areas.  The suggested initial locations are given in Figure 2.1.

2.6.2          The exact locations shall be agreed with the ER and relevant government departments prior to commencement of the monitoring programme.

2.6.3          Monitoring shall be for 14 consecutive days at two locations prior to the commissioning of the construction works to obtain daily 24-hr TSP samples (total of 28, 24-hour average measurements).  1-hr per day sampling shall also be completed for 14 days at each location (total of 84, 1-hour average measurements).

2.6.4          During the baseline monitoring programme, there shall be no construction activity or dust generation activities in the vicinity of the monitoring stations which may affect the monitoring results.

2.6.5          In exceptional cases, when insufficient baseline monitoring data or questionable results are obtained, the ETL shall liaise with the ER to agree on an appropriate set of data to be used as a baseline reference and submit to ER and relevant government departments for approval.

2.6.6          Ambient conditions may vary seasonally and shall be reviewed at three monthly intervals.  If the ETL considers that the ambient conditions have changed and a repeat of the baseline monitoring is required for obtaining the updated baseline levels, the monitoring shall be, at times when the Contractor’s activities are not generating dust, at least in the proximity of the monitoring stations.  Should a change in ambient conditions be determined, the baseline levels and, in turn, the air quality criteria, shall be revised.  The revised baseline levels and air quality criteria shall be agreed with ER and relevant government departments.

2.7              Impact Monitoring

Construction Dust

2.7.1          The ET shall carry out regular impact monitoring during the course of the Works. Monitoring shall be undertaken at 2 stations for 24-hr TSP monitoring.  A sampling frequency of one 24 hour measurement every six-days at 2 stations shall be adopted.  For 1-hour TSP monitoring, a sampling frequency of at least three times in every six days shall be undertaken.

2.7.2          In case of non-compliance with the air quality criteria, more frequent monitoring shall be conducted within 24 hours of the non-compliance.  This is specified in the Event Action Plan (see below).  Further monitoring shall be continued until the excessive dust emission or the deterioration in air quality is rectified.

Airborne Fibre Monitoring

2.7.3          The ET shall also ensure that airborne fibre monitoring is carried out by a HOKLAS accredited Registered Asbestos Laboratory in line with the Requirements of the AAP.  In addition regular airborne fibre monitoring shall be carried out daily at the boundary of the site during the course of the Asbestos Works as required by EPD.  Airborne Fibre Monitoring shall be undertaken at a minimum of 3 stations daily at locations to be confirmed with EPD.  Suggested locations for the Airborne Fibre Monitoring are presented in Figure 2.2.

2.8              Event and Action Plan for Air Quality

2.8.1          The baseline monitoring results form the basis for determining the air quality criteria for the impact monitoring.  The ETL shall compare the impact monitoring results with air quality criteria set up for 24-hour TSP and 1-hr TSP.  Table 2.1 shows the air quality criteria, namely Action and Limit levels to be used.  Should non-compliance with the air quality criteria occur, the ET, the ER and the Contractor shall undertake the relevant action in accordance with the Event Action Plan in Table 2.2.

Table 2.1         Action and Limit Levels for Air Quality

Parameters

Action

Limit*

24 Hour TSP Level in mg/m3

For baseline level < 200 mg/m                   Action level = (Baseline level * 1.3 + Limit level)/2;

For baseline level > 200 mg/m             Action level = Limit level

260

1 Hour TSP Level in mg/m3

For baseline level < 384 mg/m             Action Level = (Baseline level * 1.3 + Limit level)/2;

For baseline level > 384 mg/m             Action level = Limit level

500

Airborne fiblre level in fibres/ml

0.006 f/ml

0.01

 


Table 2.2         Event/Action Plan for Air Quality

 

 

          

ACTION


EVENT

ET

IC(E)

ER

CONTRACTOR

ACTION LEVEL

1. Exceedance for one sample

 

1.   Identify source

2.   Inform (C(E) and ER

3.   Repeat measurement to confirm finding

4.   Increase monitoring frequency to daily

1.   Check monitoring data submitted by ET

2.   Check Contractor’s working method

 

1. Notify Contractor

2. Check monitoring data and Contractor's working methods           

1.   Rectify any unacceptable practice

2.   Amend working methods if appropriate

 

2. Exceedance for two or more consecutive samples

1.   Identify source

2.   Inform IC(E) and ER

3.   Repeat measurements to confirm findings

4.   Increase monitoring frequency to daily

5.   Discuss with Contractor , IC(E) and ER for remedial actions required

6.   If exceedance continues, arrange meeting with IC(E) and ER

7.   If exceedance stops, cease additional monitoring

1.   Checking monitoring data submitted by ET

2.   Check Contractor’s working method

3.   Discuss with ET and Contractor on possible remedial measures

4.   Advise the ER on the effectiveness of the proposed remedial measures

5.   Supervise implementation of remedial measures

 

 

1. Confirm receipt of notification of failure in writing

2. Notify Contractor

3. Check monitoring data and Contractor's working methods

4. Discuss with IC(E) and Contractor on potential remedial actions

5. Ensure remedial actions properly implemented

1.   Submit proposals for remedial actions to ER within 3 working days of notification

2.   Implement the agreed proposals

3.   Amend proposal if appropriate

 

LIMIT LEVEL

 

1. Exceedance for one sample

 

1.   Identify source

2.   Inform ER and EPD

3.   Repeat measurement to confirm finding

4.   Increase monitoring frequency to daily

5.   Assess effectiveness of Contractor's remedial actions and keep IC(E), EPD and ER informed of the results

1.   Checking monitoring data submitted by ET

2.   Check Contractor’s working method

3.   Discuss with ET and Contractor on possible remedial measures

4.   Advise the ER on the effectiveness of the proposed remedial measures

5.   Supervisor implementation of remedial measures

 

 

1. Confirm receipt of notification of failure in writing

2. Notify Contractor

3. Check monitoring data and Contractor's working methods

4. Discuss with ET Leader and Contractor potential remedial actions

5. Ensure remedial actions properly implemented

1.   Take immediate action to avoid further exceedance

2.   Submit proposals for remedial actions to ER within 3 working days of notification

3.   Implement the agreed proposals

4.   Amend proposal if appropriate

 

2. Exceedance for two or more consecutive samples

1.   Identify source

2.   Inform IC(E), ER and EPD the causes & actions taken for the exceedances

3.   Repeat measurement to confirm findings

4.   Increase monitoring frequency to daily

5.   Investigate the causes of exceedance, Contractor’s working procedures to identify possible mitigation

6.   Arrange meeting with IC(E) and ER to discuss the remedial actions to be taken

7.   Assess effectiveness of Contractor's remedial actions and keep IC(E), EPD and ER informed of the results

8.   If exceedance stops, cease additional monitoring

1.   Discuss amongst ER, ET and Contractor as the potential remedial actions

2.   Review Contractor’s remedial actions whenever necessary to ensure their effectiveness and advise the ER accordingly

3    Supervise the implementation of remedial measures

 

 

 

1. Confirm receipt of notification of failure in writing

2. Notify Contractor

3. Carry out analysis of Contractor's working procedures with IC(E) to determine possible mitigation to be implemented

4. Discuss amongst Environmental Team Leader and the Contractor potential remedial actions

5. Review Contractor's remedial actions whenever necessary to assure their effectiveness

6. If exceedance continues, consider what portion of the work is responsible and instruct the Contractor to stop that portion of work until the exceedance is abated

1.   Take immediate action to avoid further exceedance

2.   Submit proposals for remedial actions to ER within 3 working days of notification

3.   Implement the agreed proposals

4.   Resubmit proposals if problem still not under control

5.   Stop the relevant portion of works as determined by the ER until the exceedance is abated


2.9              Dust Mitigation Measures

2.9.1          The EIA has discussed in general terms the appropriate dust control and mitigation measures, these are provided in more detail below.  The Contractor shall adopt all measures as required under the Air Pollution Control (Construction Dust) Regulations and implement dust suppression measures which shall include, but not be limited to, the following:-

·         Stockpiles of dusty waste materials greater than 20m3 shall be enclosed on three sides, with walls extending above the pile and 2 metres beyond the front of the pile.

·         Any vehicle with an open load carrying area used for moving potentially dusty material shall have properly fitting side and tail-boards.  Materials having the potential to create dust shall not be loaded to a level higher than the side and tail boards and shall be covered by a clean tarpaulin in good condition.  The tarpaulin shall be properly secured and shall extend at least 300mm over the edges of the side and tail-boards.

·         Effective water sprays shall be used during the collection and loading of dusty wastes and other similar materials, when dust is likely to be created and to dampen all stored materials during dry and windy weather.

·         Areas within the Site where there is a regular movement of vehicles, shall have an approved hard surface and be kept clean of loose surface material.

·         Conveyor belts shall be fitted with wind-boards, and conveyor transfer points and hopper discharge areas shall be enclosed to minimise dust emission.  All conveyors carrying materials which have the potential to create dust shall be totally enclosed and fitted with belt cleaners.

·         Adequate dust suppression plant including water bowsers with spray bars shall be provided.

·         Unless otherwise approved by the ER the Contractor shall restrict all motorised vehicles on the Site to a maximum speed of 15 km per hour and confine haulage and waste collection vehicles to designated roadways inside the Site.

2.9.2          If the above measures are not sufficient to restore the air quality to acceptable levels upon the advice of ETL, the Contractor shall liaise with the ETL on some other mitigation measures, propose to ER for approval, and implement the mitigation measures.

2.9.3          Using the above-mentioned measures and requirements in the Air Pollution Control (Construction Dust) Regulation, the dust nuisance to the surroundings shall be minimised.  In addition, the Environmental Monitoring and Audit (EM&A) for dust generated during the demolition is also recommended at the site boundary at the west to ensure that the dust criteria will not be exceeded.

2.9.4          The Contractor shall implement dust suppression measures as identified in the Schedule given in Section 8.

Table 2.3         Data Sheet for TSP Monitoring

Monitoring Location

Details of Location

Sampler Identification

Date & Time of Sampling

Elapsed-time

Start (min.)

Meter Reading

Stop (min.)

Total Sampling Time (min.)

Weather Conditions

Site Conditions

 

Pi             (mmHg)

Initial Flow Rate, Qsi

Ti            (oC)

 

Hi            (in.)

 

Qsi          (Std. m3)

 

Pf            (mmHg)

Final Flow Rate, Qsf

Tf (oC)

 

Hf            (in.)

 

Qsf          (Std. m3)

Average Flow Rate              (Std. M3)

Total Volume        (Std. m3)

Filter Identification No.

Initial Wt. Of Filter               (g)

Final Wt. Of Filter                (g)

Measured TSP Level (µg/m3)

 

 

 

Name & Designation

 

Signature

 

Date

Field Operator

:

 

 

 

 

 

Laboratory Staff

:

 

 

 

 

 

Checked by

:

 

 

 

 

 


3.                   Noise                       

3.1.1          EM&A procedures for noise are recommended to ensure that the necessary controls are implemented effectively and that the noise criteria are not exceeded.

3.2              Noise Parameters

3.2.1          The construction (demolition) noise level shall be measured in terms of the A-weighted equivalent continuous sound pressure level (Leq).  Leq (30 min) shall be used as the monitoring parameter for the time period between 0700-1900 hours on normal weekdays.  For all other time periods, Leq (5 min) shall be employed for comparison with the Noise Control Ordinance (NCO) criteria.

3.2.2          As supplementary information for data auditing, statistical results such as L10 and L90 shall also be obtained for reference.  A sample data record sheet is shown in Table 3.4 is included for reference.

3.3              Monitoring Equipment

3.3.1          As referred to in the Technical Memorandum (TM) issued under the Noise Control Ordinance (NCO), sound level meters in compliance with the International Electrotechnical Commission Publications 651: 1979 (Type 1) and 804: 1985 (Type 1) specifications shall be used for carrying out the noise monitoring. Immediately prior to and following each noise measurement the accuracy of the sound level meter shall be checked using an acoustic calibrator generating a known sound pressure level at a known frequency. Measurements shall be accepted as valid only if the calibration level from before and after the noise measurement agree to within 1.0dB.

3.3.2          Noise measurements shall be made in accordance with standard acoustical principles and practices in relation to the prevailing conditions.  Noise measurements shall not be made the presence of fog, rain, wind with a steady speed exceeding 5 ms-1 or wind with gusts exceeding 10 ms-1.  The wind speed shall be checked with a portable wind speed meter capable of measuring the wind speed in  ms-1.

3.3.3          The ET is responsible for the provision of the monitoring equipment. He shall ensure that sufficient noise measuring equipment and associated instrumentation are available for carrying out the baseline monitoring, regular impact monitoring and ad hoc monitoring. All the equipment and associated instrumentation shall be clearly labelled.

3.4              Monitoring Locations

3.4.1          The noise sensitive receivers are shown in Figure 1.1.  The monitoring locations are shown in Figure 3.1.

3.4.2          The status and locations of noise sensitive receivers may require review after issuing this manual.  It is proposed that the ET shall revise the monitoring locations to be adopted based on prevailing conditions.  These shall be agreed with the ER, IC(E) and relevant government departments.

3.4.3          Monitoring locations shall be based on the following criteria:

·         at locations close to the major site activities which are likely to have noise impacts; and

·         close to the noise sensitive receivers.

3.4.4          Monitoring locations located in the vicinity of the sensitive receivers must be operated with care to ensure minimal disturbance to the occupants during monitoring.  Monitoring at SRs premises also introduces a complication for the implementation of the baseline monitoring of permission and access at the SRs cannot be confirmed in time. Therefore in this case it is recommended that monitoring be undertaken at the site boundary, just inside the site hoarding, in an area under the control of the project proponent.  This will ensure a conservative approach. 

3.4.5          The following locations are identified as suitable monitoring locations Figure 2.1):

·         Site Boundary opposite Jockey Club Clinic/St. Luke’s Church and Lui Ming Choi Memorial Primary School *

·         Site boundary east of KTIP

·         Site boundary opposite future UPA Development in Cadogan Street, Sai Wan New Apartments, Kennedy Mansion and Cheong Kat Building

3.4.6          The sensitive receivers are sufficiently close by and for purposes of baseline monitoring purposes, three locations should be monitored.

3.4.7          Preliminary proposed monitoring locations are shown in Figure 3.1.  Each monitoring station shall normally be at a position 1.2m above the ground, just inside the site hoarding.  If there is a problem with access to the normal monitoring position, an alternative position may be chosen, and a correction to the measurements shall be made.  For reference, a correction of +3dB(A) shall be made to the free field measurements.

3.4.8          The ETL shall agree with the ER, the monitoring position and the corrections to be adopted.  Once the positions for the monitoring stations are chosen, the baseline monitoring and the impact monitoring shall be carried out at the same positions.

3.5              Baseline Monitoring

3.5.1          The ETL shall carry out baseline noise monitoring prior to the commencement of the construction works.  The baseline monitoring shall be carried out for 14 days at locations to the proposed positions to the east, south and west of the site.

3.5.2          During non-restricted hours (07:00 to 19;00) the measured parameter will be Leq 30 minutes and the baseline monitoring shall be carried out for three half hour periods per day at each of the three identified locations for a period of 14 days.  A schedule on the baseline monitoring shall be submitted to the ER for approval before the monitoring starts.  Total numbers of required Leq 30 minutes samples shall be 42.

3.5.3          There shall not be any abnormal activities in the vicinity of the monitoring stations during the baseline monitoring which would cause the monitoring results to be elevated above normal background conditions.

3.5.4          In exceptional cases, when insufficient baseline monitoring data or questionable results are obtained, the ETL shall liaise with EPD to agree on an appropriate set of data to be used as a baseline reference for approval.

3.6              Impact Monitoring

3.6.1          Noise monitoring shall be carried out at 3 locations per week.  The monitoring frequency shall depend on the scale of the construction activities.  The following defines the regular monitoring frequency for 3 stations on a per week basis when noise generating activities are underway:

a)      One set of measurements between 0700-1900 hours on normal weekdays

b)      One set of measurements between 1900-2300 hours (if evening activities are undertaken)

c)      One set of measurements between 2300-0700 hours next day (if there are night activities).

d)      One set of measurements between 0700-1900 hours on holidays (if work is undertaken)

3.6.2          For measurements b), c) and d) above, one set of measurements shall at least include 3 consecutive Leq (5 min) results.

3.6.3          As demolition activity is likely to take place near one primary school, noise monitoring shall be carried out at a monitoring station near the school during examination periods.  The ETL shall liaise with the school staff and the Examination Authority to ascertain the exact dates and times of all examination periods during the course of the contract.

3.6.4          In case of non-compliance with the construction noise criteria, more frequent monitoring may be required in line with the Event Action Plan.  This additional monitoring shall be continued until the recorded noise levels are rectified or proved to be unrelated to the demolition activities.

3.7              Event and Action Plan for Noise

3.7.1          The Action and Limit levels for construction noise are defined in Table 3.1. Should non-compliance of the criteria occur, action in accordance with the Action Plan in Table 3.2, shall be carried out.

Table 3.1         Action and Limit Levels for Construction Noise

Time Period

Action

Limit

0700-1900 hrs on normal weekdays

 

75*dB(A)

0700-2300 hrs on holidays; and 1900-2300 hrs on all other days

When one documented complaint is received

60/65/70**dB(A)

2300-0700 hrs of next day

 

45/50/55**dB(A)

*              reduce to 70dB(A) for schools and 65 dB (A) during school examination periods.

**            to be selected based on Area Sensitivity Rating as defined under the Noise Control Ordinance.

3.8              Noise Mitigation Measures

3.8.1          The EIA has discussed the noise mitigation measures in general terms.  These are given in more detail below.  Noise mitigation measures are identified in Section 10.

3.8.2          The Contractor shall consider noise as an environmental constraint in his planning and execution of the Works.

3.8.3          The Contractor shall take all necessary measures to ensure that the operation of all mechanical equipment and construction processes on or off the Site shall not cause any unnecessary and excessive noise which may disturb any occupant of any nearby dwellings, schools, clinic, or premises with sensitivity to noise.  Prior to commencement of demolition activities, the Contractor shall submit to the ER for his approval details of all Construction Plant, including methods of use and construction operations, together with proposed measures for limiting noise.  These shall include, but not be limited to, the likely location of noise-emitting plant, the use of silencers, mufflers, acoustic sheds, shields, or screens and shall be based upon the best reasonable practice.  Information on the types and models of silenced equipment and acoustic treatment for unsilenced equipment shall be included.  The Contractor shall use all such measures and shall maintain all plant and silencing equipment in good condition so as to minimise the noise emission during construction works.

3.8.4          The Contractor’s attention is drawn to all Regulations made under the Noise Control Ordinance. Those currently in force are :-

·         Noise Control (Hand Held Percussive Breakers) Regulations

·         Noise Control (Air Compressors) Regulations

·         Noise Control (Hearing Protection) Regulations

·         The Factories and Industrial Undertakings (Noise at Work) Regulations are also applicable.

3.8.5          The Contractor shall be responsible for obtaining Construction Noise Permits (CNPs) from EPD as required for his operations.  The locations of Noise Sensitive Receivers (NSRs) are indicated in Clause 3.3 of this manual, but the Contractor for obtaining and complying with EPD’s requirements regarding identification of any additional NSRs and conditions attached to CNPs.  All correspondence with EPD and each issued CNP shall be copied to the ER and IC(E).

3.8.6          The Contractor’s attention shall be drawn to the fact that other construction work in the vicinity of the Site will be taken into account by EPD in assessing applications for CNP.

3.8.7          The Contractor shall arrange methods of working to minimise noise impacts, and shall provide experienced personnel to ensure that these methods are implemented.

3.8.8          If after commencement of the Works the Construction Plant, equipment, or methods of working are believed by the ER to be causing serious noise pollution impacts, they shall be inspected and remedial proposals drawn up by the Contractor, consented to by the ER and implemented. In developing these remedial measures, the Contractor will be expected to review all construction noise sources that may be contributing to the pollution impacts in order to achieve an overall reduction of cumulative noise impacts.  The Contractor will propose changes to plant locations and scheduling of activities, installation of plant soundproofing, provision of alternative plant, erection of sound barriers around part of the Site or the location of construction noise sources, or any other measures that may be effective in reducing noise.  Where such remedial measures include the use of additional or alternative Constructional Plant or equipment, such Constructional Plant or equipment shall not be used on the Works until the ER’s consent has been given. Where remedial measures include maintenance or modification of previously approved Constructional Plant or equipment such Constructional Plant or equipment shall not be used on the Works until such maintenance or modification is completed and the adequacy of the maintenance or modification is demonstrated to the satisfaction of the ER.

3.8.9          If the above measures are not sufficient to restore the construction noise quality to an acceptable level upon the advice of ETL, the Contractor shall liaise with the ETL on alternative mitigation measures, propose to ER for Approval, and carry out the mitigation measures.


Table 3.3         Noise Monitoring Field Record Sheet

Monitoring Location

Description of Location

Date of Monitoring

Measurement Start Time     (hh:mm)

Measurement Time Length                (min.)

Noise Meter Model/Identification

Calibrator Model/Identification

 

L90           (dB(A))

Measurement Results

L10           (dB(A))

 

Leq         (dB(A))

Major Construction Noise Source(s) During Monitoring

 

Other Noise Source(s) During Monitoring

 

Remarks

 

 

 

 

Name & Designation

 

Signature

 

Date

Recorded By

:

 

 

 

 

 

Checked by

:

 

 

 

 

 


4.                   Water Quality

4.1              Sources of Water Quality Impacts

4.1.1          Surplus water may arise on site from three main sources.  During the demolition works when it rains site run-off and surface water drainage have the potential to contain elevated levels of suspended solids.  During the soil remediation phase site run-off and surface water drainage will remain as a potential impact but it may also be the case that soil decontamination procedures (including dewatering) result in the generation of surplus water for disposal.  Sewage effluents generated from the workforce may also occur in both phases.

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

4.2              Sewage Effluents

4.2.1          Sewage discharges from the demolition workforce on site shall be connected to the existing sewer and diverted to sewage treatment facilities.  If it emerges that that no sewer connection is available during certain stages of the demolition works the installation of adequate portable chemical toilets will need to be provided by a licensed contractor who will be responsible for the proper maintenance of these facilities.  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.

4.3              Site Run-off and Surface Water Drainage during Demolition

4.3.1          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.

Mitigation Measures

4.3.2          Run-off related impacts associated with demolition work and other general activities can all be 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.

4.3.3          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.

4.3.4          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.

4.3.5          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.

4.3.6          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.

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

4.3.8          All demolition works will be land based and the EIA concludes that no insurmountable water quality impacts will result from the demolition work of 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 demolition workforce sewage is discharged either to foul sewer or to temporary portable toilets, as appropriate according to the demolition programme and methodology;

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

·         All demolition works area discharges must comply with the TM standards of the WPCO in respect of all applicable WQ parameters.  Any practical options for the diversion and re-alignment of drainage should comply with both engineering and environmental requirements. General Demolition Activities

4.3.9          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 later in this report.

4.3.10      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 provide a safety margin) and control spilt fuel oils.

4.3.11      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

4.3.12      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.

4.4              Site Run-off and Surface Water Drainage during Soil Remediation

Site Run - off

4.4.1          The above mitigation shall also apply generally to all excavated and/or 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 where possible (see below).

4.4.2          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 on an area with cover and 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 minimise ingress of water.  However, impacts associated with this work and other general activities can be all readily controlled through the use of appropriate mitigation measures mentioned above.

Dewatering

4.4.3          In addition, the Contractor is strongly advised to operate any necessary ground remediation works such that discharge of groundwater should be kept to minimum.  This could be achieved by:

·         minimising the ingress of surface water, which would mix with groundwater extracted during ground excavation if any; and

·         reusing water on-site in ground remediation processes (mixing with cement).

4.4.4          In a case where any surplus groundwater is generated the Contractor must ensure that any effluent that requires to be discharged from the site satisfies the TM Requirements under the WPCO (Appendix C).

4.4.5          Surplus water arising from dewatering is to be collected on site for re-use where possible.  Groundwater and leachate shall be reused and mixed with cement in the immobilisation process for contaminated soils.  Surplus groundwater shall be collected and 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.

Treatment of Surplus Groundwater Prior to Discharge

4.4.6          Treatment methods for any surplus contaminated groundwater, such as the addition of chemicals have been covered in the EIA.  These industry standard methods will precipitate out contaminants and floating free products can be removed using an interceptor tank by flotation.  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.

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

4.5              Conclusions

4.5.1          The EIA report has recommended water quality control and mitigation measures.  The Contractor shall be responsible for the design and implementation of these measures.  Monitoring of effluents for compliance with the Marine Water Quality will not be necessary and no insurmountable water quality impacts will result from the demolition work of KTCDA provided that the above mitigation measures are implemented.


5.                   Waste Management

5.1.1          The Contractor shall be responsible for waste control within the construction site, removal of the waste material produced from the site and implementation of any mitigation measures to minimise waste or redress problems arising from the waste from the site.  The waste material will include

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

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

·         Chemical waste; and

·         General refuse.

5.1.3          The environmental impacts from the various waste types are summarised in Table 5.1.

Table 5.1         Summary of Waste Management Impacts

Waste Type

General Evaluation

C&D material

The total quantities of C&D materials which will be generated will be about 250te day-1, in comparison with the disposal capacity available at public filling areas, it is small. Due to the inert nature of most C&D material and the availability of public filling areas, disposal is not likely to raise long term environmental concerns.

Chemical Waste

A small volume of chemical waste, as well as asbestos containing roofing materials and weather cladding (estimate., up to 8,000m2) 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.

 

5.2              Mitigation Measures

Introduction

5.2.1          This section sets out recycling, storage, transportation and disposal measures which are recommended to avoid or minimise potential adverse impacts associated with waste arisings from the demolition of the 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

5.2.2          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.

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

5.2.4          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.

C&D material

5.2.5          At this stage a broad estimate up to 2500m3 of C&D materials will arise at the KTCDA demolition site each month, however this may change subject to the Contractor’s programme.   Generation of 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.

5.2.6          In accordance with the New Disposal Arrangement for Construction Waste, Environmental Protection Department, 1992, disposal of C&D material can either be at a specified landfill, or as public fill with the latter being the preferred option. However C&D materials currently comprise a high proportion of C&D waste inputs to landfills and in order to maximise landfill life, Government policy prohibits the disposal of C&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, should be segregated from any ‘contaminated’ wastes which will require landfill disposal.

5.2.7          The Contractor should recycle C&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 filling areas. Steel reinforcing bars can be re-used by scrap steel mills.

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

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

Chemical Waste

5.2.10      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.

5.2.11      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.

5.2.12      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 450l 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.

5.2.13      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 110% 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.

5.2.14      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.

5.2.15      The Centre for Environmental Technology operates a Waste Exchange Scheme which can assist in finding receivers or buyers.

5.2.16      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.

Disposal of Residual Rubble / Ash Waste (Between KTIP Chimneys)

5.2.17      EPD indicated that the PCDD/PCDF contaminated rubble / ash waste (300m3 approx.) could be disposed of at CWTC.  Remedial action has been recommended and action will be required to clean up these materials prior to the demolition.  Treatment on-site prior to disposal at a landfill is the preferred method.  This material must be immobilised on site, tested to ensure compliance with TCLP testing requirements (Appendix D) and removed by an appropriately qualified specialist contractor and must be collected, deposited at landfill in accordance with criteria and conditions as specified in agreement with EPD.

5.2.18      The proposed method of disposal is for the ash 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 material with cement.  Pilot mixing and TCLP tests should establish the ratio of cement to ash to the satisfaction of EPD.  The materials for disposal would then be treated and the extracted material placed into polythene lined steel drums.  Transparent plastic sheeting of 0.15mm thickness low-density polythene or PVC should be employed.  The drums should be 16 gauge steel or thicker and fitted with double bung fixed ends adequately sealed and well labelled in new or good condition.  Prior agreement of the disposal criteria from EPD and agreement to disposal from the landfill operator must be obtained.

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

Protection of Site Workers

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

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

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

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

5.2.24      As a fall back option the materials can be transported to the CWTC for disposal if the landfill criteria cannot be met.  No PCDD/PCDF were detected above the USEPA criterion at any other locations in soil samples.  Remedial action will be required to clean up these materials prior to the demolition.  The material that is contaminated is deposited on the walls.  As such, there is no opportunity for in-situ containment or treatment of this material in the context of the ultimate redevelopment of the site.  Therefore, there is no alternative but to dispose of this material offsite.  This should be undertaken prior to the demolition of any structures.

General Refuse

5.2.25      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.

5.2.26      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.

5.2.27      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

5.2.28      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.

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

Trip-ticket system

5.2.30      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 by the IC(E).

Training and Records of wastes

5.2.31      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).

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

5.3              Waste Management Requirements

5.3.1          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.

5.3.2          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.

5.3.3          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.

5.3.4          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.

5.3.5          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 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.

EM&A Requirements

5.3.6          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.

5.3.7          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.

5.3.8          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.


6.                   Contaminated Land

6.1              Remediation Action Plan

6.1.1          During the demolition phase, the monitoring and audit requirements recommended include a proactive approach to air quality and noise monitoring.  The demolition will only be for above ground structures but the approach should continue throughout the soil remediation phase.

6.1.2          During the subsequent soil remediation, requirements for clean-up and procedures are in line with the Guidance Notes for Investigation and Remediation of Contaminated Site documented in the EIA Report.  Actions required post demolition are presented in Table 6.1, which indicates where remedial action will be required, where reassurance/confirmatory sampling is warranted and summarises the locations requiring clean up based on the available information.  In order to make sure that all contaminated material is excavated a margin of about 0.5metre is allowed above and below the shallowest and deepest contamination detected.  In addition reassurance / confirmatory sampling is required at the boundaries of the excavations to make sure that all contaminated material is excavated.  If residual contamination is still detected by the reassurance sampling at the periphery of the excavation, the pit shall be extended one metre in the direction of the residual contamination.  The extracted soil shall be treated as with the materials already extracted in that location and reassurance / confirmatory sampling carried out again.

6.1.3          The ETL will be required to audit the working methods to ensure that the remediation is carried out according to the specification and the recommendations of the EIA.  The above recommendations for air, waste and water quality monitoring will apply.  Reassurance sampling will be required to ascertain that the remedial action plan has been carried out effectively and a summary report shall be issued to EPD at the completion of the remedial works programme.  Interim reports should also be submitted to allow EPD to monitor the progress of the remedial works.

6.2              Mitigation Measures

Management of Contaminated Soil Material

6.2.1          Although ground conditions on the site are contaminated with metals and some organic compounds, at this stage the only opportunity for human exposure to any of the contamination on site will be if the materials are excavated.  Contaminated rubble / ash waste (300m3 approx.) will be cleaned up prior to the demolition and treatment on-site prior to disposal at a landfill is the preferred method.  This material must be treated on site (see section 5) and removed by an appropriately qualified specialist contractor and must be collected, deposited at landfill in accordance with criteria and conditions as specified in agreement with EPD.

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

Volume of Soil for Immobilisation

6.2.3          The volume of soil to be treated on site has been estimated by making a broad brush estimate based on depths to which materials >Dutch B are identified by sampling.  The estimated total of about 6055m3 is preliminary and assumes that all material within 5m (10m x 10m square hole) at the contaminated depths would be treated.   This includes the 1420m3 for disposal at landfill.  The material is not disposed of off site and therefore off site effects are minimised.  However it is possible that reassurance sampling at the periphery and base of the excavations will identify further contaminated materials at a later stage, however it is not possible to predict the extent of this contamination based on current information.

Volume of Soil to Landfill

6.2.4          A volume of about 1220m3 contaminated with hydrocarbons would be directed to landfill.  Again this estimate is preliminary and assumes that all material within 5m (10m x 10m square hole) at the contaminated depths would be treated.  In this case the material is disposed off-site, however the quantities are small perhaps resulting in a few tens of lorry loads and therefore off-site effects are not expected to cause any in-surmountable environmental problems.  The precise volume of hydrocarbon contaminated waste is also difficult to determine.  However, the hydrocarbon contaminated soil appears to be confined to the lower depths at one end of the site.  Whereas it is possible that reassurance sampling at the periphery and base of the excavations will identify further contaminated materials at a later stage, it is not possible to predict the extent of any additional contamination based on current information.

6.3              Protection of Site Workers during excavation and treatment of soils

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

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

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


Table 6.1         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.*