Civil Engineering Department

The Government of the Hong Kong

Special Administrative Region

 

 

 

 

Agreement No. CE 15/99

 Environmental Impact Assessment for

 Demolition of Kwai Chung

 Incineration Plant and

 Kennedy Town CDA

 

 

 

 

 

 

Kwai Chung Incineration Plant

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-OR027-03

 

 

 

Controlled Copy No. :

 

           

 

Document Title :  Kwai Chung Incineration Plant EM&A Manual

 

 

 

Covering Letter / Transmittal Ref. No. :

                           2996/15.99/ELT           /DG/jw/OG

 

 

Date of Issue :

    September 2001

 

Revision, Review and Approval/Authorisation Records

 

 

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03

4th Issue

Various/

JWS/

DG/

02

3rd Issue

Various/

JWS/

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01

2nd Issue

Various/

JWS/

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

48 - 65

ACE

 

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


Table of Contents

1.     INTRODUCTION.. 1-1

1.1       Purpose of the Manual. 1-1

1.2       Requirement 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 KCIP. 1-4

1.6       Principles of Chimney Demolition at KCIP. 1-5

1.7       Remedial Action Plan for Contaminated Soils. 1-5

1.8       EIA 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       Monitoring Locations. 2-2

2.6       Baseline Monitoring. 2-3

2.7       Impact Monitoring. 2-3

2.8       Event and Action Plan for Air Quality.. 2-4

2.9       Dust Mitigation Measures. 2-6

3.     Noise. 3-1

3.1       Conclusions from the EIA.. 3-1

4.     Landfill Gas Precautionary Measures.. 4-1

4.1       Introduction.. 4-1

4.2       Preparation of Safety Plan.. 4-1

5.     Water Quality.. 5-1

5.1       Sources of Water Quality Impacts. 5-1

5.2       Sewage Effluents. 5-1

5.3       Site Run-off and Surface Water Drainage during Demolition.. 5-1

5.4       Site Run-off and Surface Water Drainage during Soil Remediation.. 5-2

5.5       Conclusions. 5-3

6.     Waste Management.. 6-1

6.1       Waste Management.. 6-1

6.2       Mitigation Measures. 6-1

7.     Contaminated Land.. 7-1

7.1       Remediation Action Plan.. 7-1

7.2       Mitigation Measures. 7-1

7.3       Protection of Site Workers during excavation and treatment of soils. 7-2

8.     Site Environmental Audit.. 8-1

8.1       Site Inspections. 8-1

8.2       Compliance with Legal and Contractual Requirements. 8-1

8.3       Environmental Complaints. 8-2

9.     REPORTING.. 9-1

9.1       General. 9-1

9.2       Baseline Monitoring Report.. 9-1

9.3       Monthly EM&A Reports. 9-1

9.4       Contamination Remediation Report.. 9-4

9.5       Data Keeping. 9-4

9.6       Interim Notifications of Environmental Quality Limit Exceedances. 9-4

10.       Schedule of Mitigation from the EIA.. 10-1

 

LIST OF TABLES

 

Table 1.1       Structures to be demolished at KCIP  1-3

Table 2.1       Action and Limit Levels for Air Quality  2-4

Table 2.2       Event/Action Plan for Air Quality  2-5

Table 4.1       Landfill Gas Detection Action Plan  4-2

Table 6.1       Summary of Waste Management Impacts  6-1

Table 7.1       Actions Required Post Demolition  7-3

Table 8.1       Event Contingency Plan for Environmental Complaints  8-3

Table 9.1       Sample Template for Interim Notifications of Environmental Quality Limits Exceedances  9-5

Table 10.1     Schedule of Impacts and Mitigation Measures  10-1

 

LIST OF APPENDICES

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 FIGURES

Figure 1.1         Kwai Chung Incineration Plant Constraints & Sensitive Receivers

Figure 1.2         Typical Site Hoarding

Figure 1.3         Project Organisation Chart

Figure 2.1         Proposed Dust Monitoring Location

Figure 7.1         KCIP Borehole Locations and Contaminated Locations for Remedial Action

Figure 7.2         Principle of Remedial Action Plan


LIST OF ABBREVIATIONS

AL

Action/limit

APCO

Air Pollution control Ordinance

AQO

Air Quality Objective

CNP

Construction Noise Permit

EIA

Environmental Impact Assessment

EIAO

Environmental Impact Assessment Ordinance

EM & A

Environmental Monitoring and Audit

EPD

Environmental Protection Department

ER

Engineer’s Representative

ET

Environmental Monitoring Team

ETL

Environmental Monitoring Team Leader

FIUO

Factories and Industrial Undertakings Ordinance

IC(E)

Independent Checker (Environment)

HKPSG

Hong Kong Planning Standards and Guidelines

HVS

High Volume Sampler

HyD

Highways Department

KCPTW

Kwai Chung Primary Treatment Works

NCO

Noise Control Ordinance

NSR

Noise Sensitive Receiver

SR

Sensitive Receiver

TM

Technical Memorandum

TSP

Total Suspended Particulates

USAEPA

United States of America Environmental Protection Agency

WDO

Waste Disposal Ordinance

WPCO

Water Pollution Control Ordinance

 


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 prepared for the Demolition of the Kwai Chung Incineration Plant 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 Kwai Chung Incineration Plant (KCIP) are kept to within acceptable levels;

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

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

1.1.2          This Manual contains the following:

·                     available information on the KCIP demolition project, the project organisation and demolition programme;

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

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

·                     complaints procedures; and

·                     reporting procedures.

1.1.3          The EM&A Manual has taken on a dual function since the introduction of the EIAO. These roles are:

·                     to provide a contract document between a Client and a Contractor defining the monitoring requirements and other duties in a form that is consistent with accepted contract practice.

·                     to provide additional controls that are implemented through the provisions of the Environmental Permit that are applicable to the project, but for which the responsibility does not rest with the Contractor (such as the role of the Environmental Team employed directly by the Proponent).

1.2              Requirement for EM&A Programme

1.2.1          The criteria for the requirement 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          Whereas none of the above criteria are directly applicable to the project, Criterion a) can nevertheless be viewed as relevant with respect to the possible impacts excessive dust may have on the part time staff at the Kwai Chung Primary Treatment Works (KCPTW).  There is automatic control equipment at the KCPTW next to the site and whereas such equipment is not defined as a sensitive receiver such equipment and it’s operation would also be sensitive to high dust levels and could therefore be impacted by construction activities.

1.2.3          Without mitigation for dust during the demolition phase, activities could cause nuisance to the workers or equipment at the Kwai Chung Primary Treatment Works although it is unlikely that such impacts would be prejudicial to the health or well being of people, and detrimental to the marine environment.  Also as there are potential water quality impacts, this further justifies the requirements for monitoring and audit.  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

Background

1.3.1          The KCIP is located at Kwai Yue Road, Kwai Chung, facing the Rambler Channel and Tsing Yi South Bridge, with a site area of about 14,000 m2 (Figure 1.1). The site is close to the Kwai Chung Park, the former Gin Drinkers Bay Landfill.

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

1.3.3          There is no identified long term use of the area after demolition, however, the future land use is unlikely to be residential given the close proximity of the site to Gin Drinkers Bay Landfill and the Rambler Channel Bridge.

1.3.4          A Public Fill Barging Point (PFBP), located on reclaimed land (Area 30D) to the north of the KCIP, is planned to be operational in early 2005.  The PFBP is also subject to a separate EIA study by others.

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

1.3.6          The structures that remain to be demolished at KCIP are summarised in Table 1.1.  There is currently no definite programme for the demolition of KCIP however the demolition works are planed to commence in 2003.  A twelve month demolition period has been assumed in the EIA.  There are contaminated soils and the demolition will be followed by a soil remediation programme lasting up to eight months.


Table 1.1         Structures to be demolished at KCIP

Building

Brief Description

KCIP Chimney

Reinforced concrete construction of diameter 6m – 12m and 150m high.  Internal metal flues and platforms

KCIP Buildings

High, single storey steel frame, with weather cladding, pre-cast concrete slab, reinforced concrete partitions, corrugated metal sheet external wall and roof. The overall size is approximately 83m x 92m on plan.

Weigh Bridge Office No2

Single Storey. Approximately 4m x 13m on plan.

Site Office/ Storage Buildings

Two storey high prefabricated building. Approximately 40m x 7.5m on plan.

 

1.4              Sensitive Receivers and Constraints to Demolition

Sensitive Receivers at KCIP

Residential

1.4.1          There are no residential SRs close enough to the works at KCIP which would be severely affected by demolition.  However residential receivers within 700m have been assessed in the EIA.  These include locations in the vicinity of Cheung Ching Estate and Greenfield Garden (about 600m away across the Rambler Channel, Figure 1.1).

Other Sensitivities near KCIP

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

·               The Rambler Channel marine traffic and ferry services.

·               Rambler Channel Typhoon Shelter and PCWA.

·               The Public Fill Barging Point (PFBP) at Area 30D.

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

·               The 200m Sewerage Tunnel Protection Area.

·               The Kwai Ching Primary Treatment Works.

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

·               The Rambler Channel Bridge.

·               The Tsing Yi Bridge.

·               Kwai Tai Road and heavy vehicle access.

·               Container Terminal 5 (Kwai Tai Road).

1.4.3          Due to the short distances between the chimney and the surrounding structures, the high risk and lack of cost effectiveness meant that demolition of the single chimney by blasting was reaffirmed as not feasible in the early stages of this EIA study.

1.4.4          Demolition by blasting appears to be a very high-risk option and top down demolition by more conventional means has been endorsed.  A soil remediation plan has also been developed to deal with contaminated soil under the site.  Site safety measures will need to be implemented the demolition phase and soil remediation phase, in accordance with established standards and guidelines and the findings of the landfill gas hazard assessment.

1.5              General Approach to Demolition of Buildings and Structures at KCIP

General Approach

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

1.5.2          Whereas the eventual detailed demolition plan, which would be prepared by the selected demolition Contractor(s) may not necessarily adopt the precise methodology summarised here, the general characteristics of the methods, which do not involve blasting, are appropriate.  The methods are sufficiently effective and applicable for the tasks (Appendix A).  Where possible methods that will help reduce noise and dust nuisances have been chosen.  The options selected are also broadly in line with the Draft Code of Practice for Demolition of Buildings (Buildings Department 1998).  The Draft Code of Practice for Demolition of Buildings (Buildings Department 1998) shall be observed at the detailed design stage.

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

Hoarding and Site Access

1.5.4          Typical hoardings are shown in the indicative hoarding plan (Figure 1.2).  Portable barricades should be used to cordon off different work zones within the site.  The hoardings structures should be totally within the proposed Project site and access appropriately controlled.  No members of the public or unauthorised persons should be allowed entry to the site.  Only Contractors’ personnel and Government officials should be allowed within the Contractor’s working area.

General Demolition Principles

1.5.5          Demolition of building and structures are generally in the reverse order to that of construction, progressive, level by level and having regard to type of construction.  Wherever possible, external non-load bearing cladding would be removed first.  Asbestos containing materials must be removed prior to commencement of demolition works, wherever possible.  Other ACM may need to be removed as access is gained to particular areas and as the demolition progresses.  In this project, the materials around the ACM, in some cases, will be dismantled by the civil demolition contractor, leaving the ACM in-situ (undisturbed).  The work actually involving the removal of ACM, that involves the handling of the ACM (except those exempted by the APCO) shall be carried out by an RAC.  The multi-party nature of the project and the involvement of non-asbestos contractor increase the risk of accidental disturbance of ACM.  CED will work out a detailed asbestos abatement programme for the sequence of the asbestos removal at the detailed design stage.  In view of the multiparty nature of the works the owner will be the person liable for any accidental disturbance of ACM, and hence, should take steps to prevent such disturbance.  The asbestos abatement programme shall be agreed by all parties including the supervising registered asbestos consultant (CSL), prior to the commencement of the demolition work.  A dedicated Asbestos Abatement Plan has been prepared as required under the Air Pollution Control Ordinance.

General Safety Measures

1.5.6          The Contractor must carry out works in accordance with the Factories and Industrial Undertakings Ordinance (FIUO) as well as all other statutory requirements and guidelines covering health and safety issues.  Relevant legislation has been reviewed as part of the Site Investigation Report and the Asbestos Study Report.

1.6              Principles of Chimney Demolition at KCIP

General Approach

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

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

1.6.3          The concrete supporting weather shield and the metal flues would be removed manually. The principle of the demolition procedure shall be that the chimney and flues would be cut up into pieces and these pieces lowered to the ground by derrick.  This method would ensure that full control of the debris and that the pieces of reinforced concrete are not left to free fall.

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 7.1.

1.8              EIA Requirements

1.8.1          The EIA Report recommends a range of mitigation measures to control the project’s potential environmental impacts with regard to marine water quality, dust, construction waste impacts during the demolition and the soil remediation phases.  The schedule of mitigation measures as given in the EIA Report is repeated in Section 10 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 details of the demolition works are not yet available but the estimated timing is towards the end of 2004.  The buildings and chimney at KCIP can be demolished and removed by the conventional top down demolition using hand held tools and mechanical breaking methods within one year.  The estimated time for the completion of these works based on professional experience and advice sought from local Contractors suggests 12 months would appear to be ample time for demolition based on the above methodology.   The chimney demolition would follow demolition of the main building, and weighbridge.  The EM&A programme will also cover the soil remediation work that will follow on from the demolition and may last another six to eight months.

1.10.2      This programme is for information for the ETL to get an initial idea of the sequencing of the works. It may be refined and amended by the Contractor(s).  The ET Leader shall make reference to the actual works progress and programme during the construction stage to schedule the EM&A works. The project proponent shall require Contractor(s) to provide the relevant programme information to the ETL for formulating the EM&A schedule.

1.10.3      The EM&A programme will also cover the land remediation phase, which will be undertaken following the demolition of structures.


2.                  AIR QUALITY

2.1              Air Quality Parameters

2.1.1          The major air quality issue associated with the demolition at KCIP is the potential for dust generation to cause elevated Total Suspended Particulates (TSP) levels and a nuisance at the adjacent Kwai Chung PTW.

2.2              Total Suspended Particulates

2.2.1          Monitoring and audit of TSP levels shall be carried out by the ET to detect any deterioration in air quality.  This will allow a pro-active approach to be taken in order to rectify the situation and avoid any breaches of the Hong Kong Air Quality Objectives (AQO).  The proposed location is shown in Figure 2.1.

2.2.2          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 the Title 40 of the Code of Federal Regulations, Chapter 1 (Part 50).

2.2.3          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 on the site shall be recorded in detail. 

2.3              Monitoring Equipment

2.3.1          High volume samplers (HVS) to be used for carrying out the 1-hour and 24-hour 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-hour 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-hour period.

2.3.2          The ET shall provide sufficient HVSs with the appropriate calibration kit to ensure that the baseline, impact and ad hoc 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.

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

2.4              Laboratory Measurement/ Analysis

2.4.1          A clean laboratory with constant temperature and humidity control, and 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 ETL shall provide the ER with one copy of the Title 40 of the Code of Federal Regulations, Chapter 1 (Part 50).

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-hour 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 shall be returned to the laboratory for reconditioning in the humidity controlled chamber followed by accurate weighing by an electronic balance with a readout down to 0.1 mg.  The balance shall be regularly calibrated against a traceable standard.

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

2.5              Monitoring Locations

2.5.1          Monitoring shall be conducted at one representative position at the boundary of the site adjacent to the Kwai Chung PTW.  The equipment shall therefore be as adjacent to the potentially worst affected ASR as is practical.  It is possible that the equipment could also be located within the boundary Kwai Chung PTW.  Given the reason for the choice of location there should be few practical constraints such as lack of access, power or refusal for permission to locate equipment.

2.5.2          The proposed location is shown in Figure 2.1.

2.5.3          The status and location of dust sensitive receivers shall be reviewed after issue of this Manual.  The ETL shall identify the ASR location to be adopted based on the updated construction (demolition) programme and seek approval from the ER and relevant Government Departments.

2.5.4          The monitoring location should be chosen based on the following criteria:

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

·         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 from any supporting structure, measured horizontally is required;

·         no active furnace or active incinerator flues should be nearby;

·         airflow around the sampler should be unrestricted;

·         the sampler should be more than 20 metres from any dripline;

·         any wire fence and gate, to protect the sampler, should 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 is needed to operate the samplers.

2.6              Baseline Monitoring

Total Suspended Particulates

2.6.1          The ETL shall carry out baseline monitoring as close to the Kwai Chung PTW as is practical at a location agreed with EPD.

2.6.2          The exact locations should be agreed with the ER and relevant Government Departments prior to commencement of the monitoring programme and subject to practical considerations.  If practical, this should match with the proposed permanent location for the monitoring equipment.

2.6.3          Monitoring shall be for 14 consecutive days prior to the commissioning of the demolition works to obtain daily 24-hour average TSP samples (total of 14 24-hour average measurements).

2.6.4          Construction or dust generation activities from the project with potential to affect the results shall not have commenced in the vicinity of the monitoring stations.

2.6.5          In exceptional cases, where 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 for approval and relevant Government Departments.

2.6.6          Ambient conditions may vary seasonally and shall be reviewed at three monthly intervals.  The ETL may consider that the ambient conditions have changed and a repeat of the baseline monitoring is required in order to obtain the updated baseline levels.  If so the new monitoring, to confirm ambient conditions, should be at times when the Contractor’s activities are not generating dust, at least in the proximity of the monitoring stations.  Should changes in ambient conditions be determined, the baseline levels and, in turn, the air quality criteria, should be revised.  The revised baseline levels and air quality criteria should be agreed with ER and relevant Government Departments.

2.7              Impact Monitoring

Total Suspended Particulates

2.7.1          The ET shall carry out regular impact monitoring during the course of the works. Monitoring shall be undertaken at 1 location for 24-hour TSP monitoring.  A sampling frequency of one 24 hour measurement every six-days shall be adopted.

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 Action Plan.  Further monitoring shall be continued until the excessive dust emission or the deterioration in air quality is rectified.

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.  Table 2.1 shows the air quality criteria, namely Action and Limit levels, to be used.  Should non-compliance of the air quality criteria occur, the ET, the ER and the Contractor(s) shall undertake the relevant action in accordance with the Action Plan in Table 2.2. Reference should be made to Appendix B for the IC(E)'s role (not included in the main body of the report as this does not form part of the contractual requirements of the EM&A Manual).

 

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

 


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 report has discussed in general terms the appropriate dust control and mitigation measures, these are provided in more detail below.

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

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

2.9.4          In order that nuisance to the Kwai Chung PTW is minimised, it is important to minimise dust emissions from construction activities.  The Air Pollution Control (Construction Dust) Regulation control dust emission from construction works.  Appropriate dust control measures should be implemented during construction stage in accordance with the requirements in the Air Pollution Control (Construction Dust) Regulations.  Dust control techniques should be considered to control dust to a level not exceeding the Air Quality Objectives (AQOs).  These measures include:

·                     Adoption of good site practices;

·                     Avoid practices likely to raise dust level;

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

·                     Reducing drop height during material handling or wall felling;

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

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

·                     Regular plant maintenance to minimise exhaust emission; and

·                     Collection and sweeping up of accumulations of surplus dust and debris at the end of each shift.

2.9.5          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 at the Kwai Chung PTW.

2.9.6          The Contractor shall implement dust suppression measures as identified in the Schedule given in Section 10.


3.                  Noise

3.1              Conclusions from the EIA

3.1.1          The predicted noise levels at the NSRs will be within the established criteria, without mitigation, due to the great separation distance to the NSRs.  Therefore, noise exceedances during the demolition works are not expected and although no EM&A is recommended at this stage, it is recommended that good site practices should be adopted so as to avoid unnecessary noise generated by any construction/demolition works (such as machine idling) as far as practicable.  Event contingency plans for complaints are presented later in this report.

.


4.                  Landfill Gas Precautionary Measures

4.1              Introduction

4.1.1          There is a need to ensure that adequate precautionary measures are taken during the demolition and the subsequent ground remediation works to ensure that any risks posed by landfill gas are adequately addressed.  These measures shall be applicable to all works deemed by the ER to be either confined spaces, or any other location or activity considered susceptible to landfill gas build-up (hereinafter referred to as ‘qualifying works’).

4.2              Preparation of Safety Plan

4.2.1          It is recommended that a safety plan is included as a deliverable under the contract.  This safety plan should include a specific section on landfill gas safety.  This document should be submitted to the ER for review and approval prior to submission to EPD.  This shall be prepared and endorsed prior to undertaking any qualifying works.

4.2.2          The safety plan should set out the measures and implementation strategies proposed to minimize, inter alia: the risk of fires, uncontrolled explosions and asphyxiation of workers during the qualifying works.  Amongst other issues, the safety plan should stipulate the gas monitoring required (in terms of frequency and location) prior to and during the use of all powered mechanical equipment for qualifying works.  All qualifying works and staff training should be undertaken strictly in accordance with the Safety Plan.  Information to be incorporated into the Safety Plan, and other requirements, include:

·                     details of responsible parties and timeframes for actions/responses to different monitoring scenarios, details of essential staff training requirements, and requirements for back-up monitoring equipment should also be provided;

·                     all relevant workers should undergo training about the risks and indications of landfill gas and should be thoroughly versed in first aid and emergency and evacuation techniques;

·                     a no smoking policy should be strictly applied;

·                     the possibility of methane rich air being taken into diesel-engined plant should not be overlooked;

·                     provisions should also be made to control water contamination that may arise if leachate infiltrates from the landfill;

·                     a mechanical ventilation system should be in use at all times when personnel are working on qualifying works.  No such works should be carried out in the absence of mechanical ventilation or without the presence of a suitably trained safety officer.

·                     all electrical equipment (including extension leads) should be fitted with spark arrestors or be intrinsically safe;

·                     as a minimum, no qualifying works should be undertaken in the absence of fire extinguishers or emergency breathing apparatus (details should be provided in the safety plan);

·                     monitoring of methane, carbon dioxide and oxygen should be undertaken at all times during qualifying works using suitable equipment.  Specific details of measurement equipment, personnel, lines of responsibility and monitoring frequency should be set out in the Safety Plan.  The actions set out in Table 4.1 below will be carried out in the event of gas trigger levels being breached.

 

Table 4.1         Landfill Gas Detection Action Plan

Parameter

Measurement

Required Action

O2

< 19 %

Increase ventilation to restore O2 to >19%

< 18 %

Stop work

Evacuate Personnel

Increase ventilation to restore O2 to >19%

CH4

> 10 % LEL

Prohibit hot works

Increase ventilation to restore CH4 to < 10 % LEL

> 20 % LEL

Stop work

Evacuate Personnel

Increase ventilation to restore CH4 to < 10 % LEL

CO2

> 0.5 %

Increase ventilation to restore CO2 to < 0.5 %

> 1.5 %

Stop work

Evacuate Personnel

Increase ventilation to restore CO2 to < 0.5 %

 

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

 

Methane

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

Carbon Dioxide

0 - 20 % v/v

Oxygen

0 - 21 % v/v

 

4.2.4          As a minimum:

·         monitoring frequency should be on an hourly basis and should always be undertaken by suitably qualified personnel; and

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

4.2.5          All measurements should be recorded and included in the site diary.  This should be reflected in the Safety Plan.  Some basic site safety precautions recommended in the EIA are included at Appendix E.


5.                  Water Quality

5.1              Sources of Water Quality Impacts

5.1.1          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.

5.1.2          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 KCIP.  All discharges from the site shall be controlled in order to comply with the standards for effluents discharged into the Victoria Harbour WCZ under the TM.

5.2              Sewage Effluents

5.2.1          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.

5.3              Site Run-off and Surface Water Drainage during Demolition

5.3.1          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

5.3.2          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.

5.3.3          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.

5.3.4          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.

5.3.5          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.

5.3.6          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.

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

5.3.8          All demolition works will be land based and the EIA concludes that no insurmountable water quality impacts will result from the demolition work of KCIP provided that:

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

·            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

5.3.9          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.

5.3.10      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.

5.3.11      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

5.3.12      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.

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

Site Run - off

5.4.1          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).

5.4.2          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 a concrete covered area with bunding to control run-off, especially if heavy rain were to occur during the period while the cement sets.  Bunding or sand-bagging around the excavated pits is also recommended to minimise ingress of water.  However, impacts associated with this work and other general activities can be all readily controlled through the use of appropriate mitigation measures mentioned above.

Dewatering

5.4.3          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).

5.4.4          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).

5.4.5          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.  If the concentrations of contaminants exceed the standards the surplus water shall be treated.

Treatment of Surplus Groundwater Prior to Discharge

5.4.6          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.

5.4.7          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.

5.5              Conclusions

5.5.1          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 KCIP provided that the above mitigation measures are implemented.

.


6.                  Waste Management

6.1              Waste Management

6.1.1          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.

6.1.2          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.

6.1.3          The environmental impacts from the various waste types are summarised in Table 6.1.

Table 6.1         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 200te 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 louvres (preliminary estimate, up to 2,000m3) 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.

 

6.2              Mitigation Measures

Introduction

6.2.1          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 KCIP, 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 ad be in compliance with the Works Bureau Technical Circular No. 29/2000 – Waste Management Plan.

Waste Management Hierarchy

6.2.2          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.

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

6.2.4          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

6.2.5          At this stage a broad estimate up to 1500m3 of C&D materials will arise at the KCIP demolition site each month.  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.

6.2.6          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 at a public filling facility 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.

6.2.7          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.

6.2.8          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 KCIP takes place.

6.2.9          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

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

6.2.11      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.

6.2.12      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 450 l unless the specifications have been approved by the EPD; and

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

6.2.13      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 100% of the volume of the largest container or 20% by volume of the chemical waste stored in that area, whichever is the greatest;

·                     Have adequate ventilation;

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

·                     Be arranged so that incompatible materials are adequately separated.

6.2.14      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.

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

6.2.16      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 Ash Waste (Ash Bunker Wall)

6.2.17      EPD indicated that the PCDD/PCDF contaminated ash waste (20m3 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.

6.2.18      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 in line with the Guidance Notes for Investigation and Remediation of Contaminated Site.  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.

6.2.19      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

6.2.20      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.

6.2.21      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.

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

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

6.2.24      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

6.2.25      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.

6.2.26      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.

6.2.27      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

6.2.28      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.

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

Trip-ticket system

6.2.30      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

6.2.31      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).

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

Waste Management Requirements

6.2.33      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.

6.2.34      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.

6.2.35      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.

6.2.36      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.

6.2.37      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

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

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

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


7.                  Contaminated Land

7.1              Remediation Action Plan

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

7.1.2          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 7.1, 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 boudaries 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 (Figure 7.2).

7.1.3          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.

7.2              Mitigation Measures

Management of Contaminated Soil Material

7.2.1          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 ash waste (20m3 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 6) 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.

7.2.2          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

7.2.3          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 1750m3 is preliminary and assumes that all material within 5m (10m x 10m square hole) at the contaminated depths would be treated (Figure 7.1).   This excludes the 450m3 for disposal at landfill.  The material is not disposed of off site and therefore off site effects are minimised.  However it is possible that reassurance sampling at the periphery and base of the excavations will identify further contaminated materials at a later stage, however it is not possible to predict the extent of this contamination based on current information.

Volume of Soil to Landfill

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

7.3              Protection of Site Workers during excavation and treatment of soils

7.3.1          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.

7.3.2          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.

7.3.3          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 7.1 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

B1

Yes

Down to 1m depth

1m to 2m

Immobilisation *

100

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

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

B2

Yes

Down to 2m depth

2m to 3m

Immobilisation *

100

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

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

B3

Yes

Down to 2m depth

2m to 3.5m

Immobilisation *

150

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

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

B4

Yes

Concrete down to 1.5m depth

Below concrete down to 2m

Immobilisation *

50

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

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

B5

Yes

Down to 1.5m depth

1.5m to 3.5m

Immobilisation *

200

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

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

B6

Yes

Concrete down to 0.4m depth

Below concrete down to 1.4m

Immobilisation *

100

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

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

B7

Yes

Concrete down to 0.9m depth

Below concrete to 1.9m

Immobilisation *

100

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

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

B8

No Clean Up

N/A

N/A

N/A

N/A

N/A

N/A

B9

No Clean Up

N/A

N/A

N/A

N/A

N/A

N/A

B10

No Clean Up

N/A

N/A

N/A

N/A

N/A

N/A

B11

Yes

Down to 1.5m depth

1.5m to 3.5m

Immobilisation *

200

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

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

B12

No Clean Up

N/A

N/A

N/A

N/A

N/A

N/A

B13

No Clean Up

N/A

N/A

N/A

N/A

N/A

N/A

B14

No Clean Up

N/A

N/A

N/A

N/A

N/A

N/A

B15

Yes $$

Excavate concrete down to 0.9m.  (TPH contamination  as bolus of tarry bitumen at 0.9m (only).

0.9m to 2.0m

TCLP test followed by removal of 1m to 2m landfill.  Immobilisation if necessary **. @

110

Yes, determine extent of HM (Cu and TPH) contamination. * $$

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

B16

No Clean Up

N/A

N/A

N/A

N/A

N/A

N/A

B17

No Clean Up

N/A

N/A

N/A

N/A

N/A

N/A

B18

Yes

Excavate concrete down to 0.6m depth

Below concrete (0.6m) down to 1.6m

TCLP test followed by removal of 0.6m to 1.6m  to landfill, @.

100

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

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

B19 (surface)

No Clean Up

Concrete down to 1.6m depth

N/A

N/A

N/A

N/A

N/A

B19 (middle)

Yes

N/A

1.6m down to 2.6m

Immobilisation.

100

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

5 samples 5m N, S, E ,W of borehole,

B19 (bottom)

Yes

N/A

2.6m down to rockhead (say 3.2m)

TCLP test followed by removal of 2.6m to 3.6m landfill. Immobilisation if necessary **, @.

<100

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

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

B20

No clean Up

Down to 2.5m depth

N/A

N/A

N/A

N/A

N/A

B20

Yes

N/A

2.5m to 4.0m (or  rockhead)

TCLP test followed by removal of 2.5m to 4m to landfill. Immobilisation if necessary**, @

150

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

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

B21 (top)

No Clean Up

Concrete down to 2.5m Remove soil to 4.0m depth

Assume surface to 4.0m not contaminated.

N/A

N/A

N/A

N/A

B21 (bottom)

Yes

N/A

4.0m to 6.0m contaminated

Immobilisation *

200

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

5 samples 5m N & S, 2m E & W and base of borehole.

B22

Yes

Concrete down to 1.5m depth

Immediately below concrete at 1.5m down to 4.0m (or rockhead)

Immobilisation*

250

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

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

B23

Yes

Down to 1.5m depth

Immediately below concrete at 1.5m to 3.5m contaminated.

Immobilisation*

200

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

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

Refuse and Ash Bunkers

Yes

N/A

N/A

Landfill disposal

To be determined after inspection of bunkers

Examine bunker refuse prior to demolition

Consider analysis depending on bunker contents

Main Hall Ash Bunker Wall

Yes

N/A

 

Remove ash under controlled conditions up to 5m up wall.  Landfill disposal to meet EPD criteria.

Assume materials within 5m of ground contaminated

Visual inspection of walls to ensure all visible dust and debris removed.

-

Main Hall Floors

Yes

N/A

-

Remove ash under controlled conditions up to 5m from wall.  Landfill disposal to meet EPD criteria.

Assume materials within 5m of wall contaminated.

Visual inspection of floor within 5m of wall to ensure all visible dust and debris removed.

-

Chimney

Reassurance sampling only

N/A

 

 

 

Review requirements after demolition and confirmatory sampling.

-

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

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

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

#              According to the quantity of contaminated material estimated for each borehole location, the total quantity of contaminated soil should be about 2200m3. .

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

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


8.                  Site Environmental Audit

8.1              Site Inspections

8.1.1          Site Inspections provide a direct means to trigger and enforce the specified environmental protection and pollution control measures.  Pollution control measures shall be undertaken routinely and results catalogued in a site diary to facilitate inspection of the construction activities in order to ensure that appropriate environmental protection and pollution control mitigation measures are properly implemented.  With well defined pollution control and mitigation specifications and a well established site inspection, deficiency and action reporting system, the site inspection is one of the most effective tools to enforce the environmental protection requirements on the construction site.

8.1.2          The ETL is responsible for formulation of the environmental site inspection, deficiency and action reporting system, and for carrying out the site inspection works.  He shall submit a proposal on the site inspection, deficiency and action reporting procedures within 21 days of the construction contract commencement to the Contractor for agreement and to the ER for approval.

8.1.3          Regular site inspections shall be carried out at least once per week.  The areas of inspection shall not be limited to the environmental situation, pollution control and mitigation measures within the site.  They should also review the environmental situations outside the Site that are likely to be affected, directly or indirectly, by the site activities.  The ETL shall make reference to the following information in conducting the inspections:

·                     the EIA Report recommendations on environmental protection and pollution control mitigation measures;

·                     works progress and programme;

·                     individual works methodology proposals (which shall include proposals on associated pollution control measures);

·                     the contract specifications on environmental protection;

·                     the relevant environmental protection and pollution control laws; and

·                     previous site inspection results.

8.1.4          The ETL shall request all information regarding the construction contract from the Contractor required for him to carry out the site inspections. The inspection results and their associated recommendations on improvements to the environmental protection and pollution control works shall be submitted to the ER and the Contractor within 24 hours, for reference and for taking immediate action. The Contractor shall follow the procedures and time-frame as stipulated in the environmental site inspection, deficiency and action reporting system formulated by the ETL to report on any remedial measures subsequent to the site inspections.

8.1.5          Ad hoc site inspections shall also be carried out if significant environmental problems are identified. Inspections may also be required subsequent to receipt of an environmental complaint, or as part of the investigation work, as specified in the Action Plan for environmental monitoring and audit.

8.2              Compliance with Legal and Contractual Requirements

8.2.1          The demolition activities shall comply with all contractual environmental protection and pollution control requirements as well as environmental protection and pollution control laws in Hong Kong.

8.2.2          In order that the works are in compliance with the contractual requirements, all the works method statements submitted by the Contractor to the ER for approval shall be sent to the ETL for vetting to see whether sufficient environmental protection and pollution control measures have been included.

8.2.3          The ETL shall also review the progress and programme of the works to check that relevant environmental laws have not been violated, and that any foreseeable potential for violating the laws can be prevented.

8.2.4          The ETL shall regularly request copies of relevant documents from the Contractor so that the checking work can be carried out.  The documents shall at least include the updated Work Progress Reports, the updated Works Programme, the application letters for different licenses/permits under the environmental protection laws, and all the valid licenses/permits.  The site diary shall also be available for the ETL’s inspection upon his request.

8.2.5          After reviewing the document, the ETL shall advise the ER and the Contractor of any non-compliance with the contractual and legislative requirements on environmental protection and pollution control for them to take follow-up actions.  If the ETL’s review concludes that the current status on license/permit applications and any environmental protection and pollution control preparation works may not cope with the works programme he shall also advise the Contractor and the ER accordingly.  If the ETL’s review concludes that the current status may result in potential violation of environmental protection and pollution control requirements by the works in due course, he shall also advise the Contractor and the ER accordingly.

8.2.6          Upon receipt of the advice, the ER shall follow up to ensure that appropriate action has been taken by the Contractor in order to ensure that the environmental protection and pollution control requirements are fulfilled.

8.3              Environmental Complaints

8.3.1          Complaints shall be referred to the ETL for carrying out complaint investigation procedures. The ETL shall undertake the following procedures upon receipt of any complaints:

·                     log complaint and date of receipt onto the complaint database;

·                     investigate the complaint to determine its validity, and to assess whether the source of the problem is due to works activities;

·                     if a complaint is valid and due to works, identify mitigation measures;

·                     if mitigation measures are required, advise the Contractor accordingly;

·                     review the Contractor’s response on the identified mitigation measures, and the updated situation;

·                     if the complaint is submitted by EPD, submit interim report to EPD on status of the complaint investigation and follow-up action within the time frame agreed between the ER and relevant Government Departments;

·                     undertake additional monitoring and audit to verify the situation if necessary, and review that any valid reason for complaint does not recur;

·                     report the investigation results and the subsequent actions to the source of the complaint for responding to the complainant (if the source of complaint is EPD, the results should be reported within the time frame agreed with the ER and relevant Government Departments); and;

·                     record the complaint, investigation, the subsequent actions and the results in the monthly EM&A reports.

8.3.2          During the complaint investigation work, the Contractor shall provide all the necessary information and assistance for completion of the investigation. If mitigation measures are identified in the investigation, the ER shall advise the Contractor to promptly carry out the mitigation (the ER will have the authority to require that the measures are carried out). The ET shall inspect measures that have been carried out by the Contractor and advise ER of their acceptability.

Table 8.1         Event Contingency Plan for Environmental Complaints

Step

Day

Action

Contractor

ER

ET

IC(E)

1

1

Party receiving complaint shall create a new complaint record. If the Contractor receives a complaint, he shall pass the information to the ER. 

¨

¨

¨

 

2

1

ER to ensure details of complaint provided to Contractor (if complaint not originally received by the Contractor), ET and IC(E)

 

¨

 

 

3

2

Within 1 working day after the receipt of the Notification of Complaint, provide ER relevant works site information, e.g. types and locations of construction works.

¨

 

 

à

4

2

Investigate the complaint to determine its validity, and to assess whether the source of the problem is due to the works activities.  Report the validity of the complaint to ER.

 

 

 

¨à

5

2

If complaint is valid and due to works, ER shall notify the Contractor.  If complaint is invalid or not due to works, Go to Step 12.

 

¨

 

 

6

2

Propose mitigation measures to ER within 1 working day of the receipt of the Notification.

¨

 

 

à

7

2

Review and agree with the proposed mitigation measures and make recommendations where necessary.

 

¨à

 

¨à

8

2

Implement the mitigation measures once they have been agreed.

¨

 

 

 

9