1.                   INTRODUCTION

 

Purpose of the Manual

 

1.1               The purpose of this Environmental Monitoring and Audit (EM&A) Manual is to guide the set up of an EM&A programme for the implementation of the Environmental Impact Assessment (EIA) Study recommendations, to evaluate the effectiveness of the recommended mitigation measures and to identify any further need for additional mitigation measures or remedial action.  This Manual outlines the monitoring and audit programme for the construction and operation phases of the proposed project, namely “Harbour Area Treatment Scheme (HATS) Stage 2A EIA Study – Investigation” (hereinafter referred to as “the Project”).  It aims to provide systematic procedures for monitoring, auditing and minimising environmental impacts associated with construction works and operational activities.

 

1.2               Hong Kong environmental regulations and the Hong Kong Planning Standards and Guidelines have served as environmental standards and guidelines in the preparation of this Manual.  In addition, the EM&A Manual has been prepared in accordance with the requirements stipulated in Annex 21 of the Technical Memorandum on the EIA Process (EIAO-TM).

 

1.3               This Manual contains the following information:

·         responsibilities of the Project Proponent, Contractor, the Engineer or Engineer’s Representative (ER), and Environmental Team (ET), Independent Environmental Checker (IEC), Drainage Services Department (DSD), Monitoring Team and Environmental Consultant (EC) with respect to the environmental monitoring and audit requirements during the course of the Project

·         project organisation for the Project

·         the basis for, and description of the broad approach underlying the EM&A programme

·         requirements with respect to the construction programme and the necessary environmental monitoring and audit programme to track the varying environmental impact

·         methodologies to be adopted, including all field, laboratories and analytical procedures, and quality assurance and quality control programme (e.g. calibration of monitoring equipment)

·         definition of Action and Limit levels

·         establishment of Event and Action plans

·         procedures for environmental complaints handling

·         requirements for reviewing pollution sources and working procedures required in the event of non-compliance with the environmental criteria and complaints

·         requirements for presentation of environmental monitoring and audit data and appropriate reporting procedures

·         requirements for review of EIA predictions and the effectiveness of the mitigation measures / environmental management system and the EM&A programme

 

1.4               The ET leader, who shall be responsible for and in charge of the ET, is the person responsible for executing the EM&A requirements.

 

Project Background

 

1.5               The Harbour Area Treatment Scheme (HATS, formerly known as Strategic Sewage Disposal Scheme) is to improve water quality in Victoria Harbour by intercepting and treating sewage from developments on both sides of the harbour.  The HATS comprises two stages: 1 and 2.

 

1.6               In stage 1 of HATS which was commissioned in the end of 2001, about 75% of sewage generated around Victoria Harbour was collected and treated before discharge.  Water quality in the eastern part of Victoria Harbour has improved significantly since then.

 

1.7               The remaining 25% of the sewage is only subject to preliminary screening prior to discharge into Victoria Harbour, where it exerts a significant negative effect on water quality.  With the anticipated growth in population and business activities in the harbour area, water quality will be deteriorated in the future unless the sewage, generated by a population of approximately one million people living on the northern and western shores of Hong Kong Island, is intercepted and treated, and the overall treatment level at Stonecutters Island is raised by completing HATS Stage 2.

 

1.8               Based on recommendations of an earlier international review in 2000 and subsequent environmental & engineering feasibility studies conducted over 2002 and 2003, as well as the public’s views collected through a five-month long consultation in 2004, the Government is committed to proceeding with Stage 2 of HATS in two phases, namely Stage 2A and Stage 2B. 

 

·         Under Stage 2A, deep tunnels will be built to bring sewage from the northern and western areas of Hong Kong Island to Stonecutters Island Sewage Treatment Works (SCISTW).  The treatment works will be expanded to provide centralized chemically enhanced primary treatment and disinfection for all sewage from the whole of the HATS catchment.  Part of the Stage 2A disinfection facilities will be fast-tracked for completion in 2009. 

·         Under Stage 2B, a new secondary level (biological) treatment plant on a site adjacent to SCISTW is proposed to treat all HATS flow.  Planning for Stage 2B is in hand, with a view to completing it in time to suit actual sewage flow build up and water quality conditions. 

 

Project Scope and Programme

 

1.9               Under Stage 2A (hereinafter referred to as the Project), the scope of work includes:

 

·         Upgrading of eight existing preliminary treatment works (PTW) on Hong Kong Island

·         Extension of the deep sewage conveyance system (SCS) to collect and transfer sewage from the above PTWs to SCISTW for treatment and disposal

·         Augmentation of the existing Chemical Enhanced Primary Treatment (CEPT) capacity at SCISTW from the present design capacity of 1.7million m3/day to the ultimate design capacity (which is estimated at about 2.45million m3/day based on latest available information)  

·         Provision of disinfection to all HATS effluent before discharging into the harbour

 

1.10            The general layout plan of the HATS Stage 2A is shown in Figure 1.1.

 

1.11           It is intended that HATS Stage 2A will be procured using a “design-build” arrangement, where the construction contractor will be responsible for final detailed design to provide Government with the most cost-effective and operationally optimal solution.  On this basis, it is anticipated that construction of the various elements of the Project will commence progressively, with the first “detailed design and construction” contract to be awarded in early 2009 and others to follow within two years.  The construction (including testing and commissioning) of the whole of HATS Stage 2A is scheduled to complete by 2014.  The tentative construction programme is given in Figure 1.3.

 

1.12            Noting that the discharge of un-disinfected sewage effluent from SCISTW is contributing to unsatisfactory beach water quality at the Tsuen Wan beaches, the Government has also proposed to advance the provision of part of the permanent disinfection facilities under HATS Stage 2A for completion in 2009.  This proposal is hereafter referred to as the “Advance Disinfection Facilities” (or ADF), and is covered in a separate EIA study[1].  

 

Project Description

 

Overview of Proposed Scheme for HATS Stage 2A

 

1.13            The operational philosophy of HATS Stage 2A is similar to HATS Stage 1.  That is, sewage from the catchments will be:

 

·         Firstly, screened and de-gritted at the PTWs to remove large solid objects and sediments, so as to protect the downstream sewer tunnels from blockage or excessive sedimentation

·         Then, discharged into the SCS, consisting of sewer tunnels or pipelines, which conveys the screened/de-gritted sewage to SCISTW

·         Finally, treated (and disinfected) at SCISTW, to a level suitable for discharge via a marine outfall system into the sea (off the western anchorage area)

 

1.14            Sludge drawn from the sedimentation process will be dewatered in SCISTW, and then transported offsite for final treatment and/or disposal in accordance with Government’s strategy for sewage sludge management.

 

Preliminary Treatment Works

 

1.15            Eight existing PTWs on northern and western Hong Kong Island, including North Point, Wan Chai East, Central, Sandy Bay, Cyberport, Aberdeen, Wa Fu, and Ap Lei Chau would be upgraded/ modified to meet design treatment and flow requirements.  Principally, the major upgrading works would include replacement of the following major plant and equipment:

 

·         Mechanical screens of various sizes

·         Pumps

·         Grit traps (sedimentation tanks)

·         Compactors (for solid residues processing)

·         Deodorising units (e.g., bio-filters and/or activated carbon filters)

 

1.16            Construction works would be carried out in phases in order to provide areas for normal PTW operation and SCS construction.  Conventional construction plant and equipment (e.g. dozers, backhoes, dump trucks, hydraulic breakers, cranes, etc) would be used to upgrade the PTWs. 

 

Sewage Conveyance System

 

1.17            The HATS Stage 2A SCS includes vertical shafts that pick up sewage from the PTWs.  Sewage from the PTWs is discharged via drop shafts in the deep tunnels (total length about 21 km at a depth of about 70m to 160m below sea level) and then conveyed to the SCISTW.

 

1.18            In general, the SCS includes seven main tunnel sections, 16 temporary/permanent shafts, and up to 3 sewage transfer pumping stations and two ancillary seawater pumping stations at strategic locations in the SCS.  To facilitate the SCS construction, 20 temporary/permanent works areas are required which are used for shaft construction or as supporting areas for temporary stockpile/storage during construction stage.  

 

1.19            Either mechanical boring or “drill and blast” could be used to excavate the main tunnel sections, depending on the anticipated ground conditions and other site-specific considerations (e.g., construction logistics, proximity to sensitive receivers, etc).  The shafts would be constructed using conventional techniques, i.e., mechanical excavation of the near surface softer materials by diaphragm-walling techniques, and blasting/mechanical boring for the deeper harder (rock) materials.  For construction of sewage transfer/seawater pumping stations, conventional construction plant and equipment (e.g. dozers, backhoes, dump trucks, hydraulic breakers, cranes, excavators etc) would be used.  If piling is required, non-percussive piling method would be used.

 

Expansion of SCISTW

 

1.20            Augmentation of the existing SCISTW to meet design flow and treatment performance requirements includes:

 

·         A new Influent Pumping Station, which will be interconnected with the existing SCISTW Main Pumping Station (constructed in HATS Stage 1)

·         Additional sedimentation (i.e., CEPT) facilities, to be located adjacent to the existing CEPT tanks

·         Upgraded effluent disinfection facilities (over and above the Advance Disinfection Facilities being implemented ahead of HATS Stage 2A), consisting of two new sodium hypochlorite storage tanks, a new chlorine contact tank, and dechlorination facility

·         A new Effluent Conveyance System and associated chamber, consisting of a deep sewer tunnel connecting the CEPT tanks and the new chlorine contact tank, and the discharge culvert to Chamber 15.   A new Chamber 15A and an extension of the existing Chamber 15 would be added to the effluent conveyance system

·         Additional sludge processing (dewatering) facilities, located adjacent to the existing sludge building

·         A new odour treatment system, based on use of bio-filtration and activated carbon filtration technologies

·         Ancillary facilities, including high-voltage electrical substation

 

1.21            The proposed layout of the SCISTW upgrading is shown in Figure 1.2.

 

1.22            The construction methods for most of the proposed facilities would follow standard practices, involving piling (bored piles) if required to form foundations, building/structure construction, and then equipment installation.  Construction of the effluent tunnel would be by either mechanical boring or “drill and blast”.  Other elements would be constructed using conventional construction plant and equipment (e.g. dozers, backhoes, dump trucks, hydraulic breakers, cranes, etc), for which the choice of equipment would lead to less environmental impacts. 

 

Environmental Parameters to be Monitored

 

1.23            With reference to the recommendations made in the EIA Study, the environmental parameters to be monitored in baseline, construction and operation phases are presented as follows.  The proposed monitoring programme is presented in subsequent sections of this EM&A Manual.

 

Baseline

·         Air quality (dust) impact monitoring

·         Air quality (odour) impact monitoring

·         Airborne noise impact monitoring

·         Pre-translocation monitoring for coral

·         Landscape and visual monitoring

 

Construction Phase

·         Air quality (dust) impact monitoring

·         Airborne noise impact monitoring

·         Post-translocation monitoring for coral

·         Cultural heritage vibration monitoring

·         Landscape and visual monitoring

·         Ground vibration/settlement monitoring due to hazard in relation to Potential Hazardous Installations

 

Operation Phase

·         Odour monitoring

·         Water quality impact monitoring

·         Human health and ecological risk evaluation

·         Sediment quality monitoring and benthic survey

·         Landscape and visual monitoring

 

Project Organisation

 

1.24            The roles and responsibilities of the various parties involved in the construction phase and operation phase of the EM&A process and the implementation of the EM&A programme are outlined below.  The proposed project organisation and lines of communication during construction and operation phases with respect to environmental protection works are shown in Figures 1.4 and 1.5 respectively.

 

Construction Phase

 

Project Proponent

 

1.25            The Project Proponent is the organization proposing the development of the Project.  The Project Proponent should:

 

·         Employ an Environmental Team (ET) to undertake monitoring, laboratory analysis and reporting of EM&A

·         Employ an Independent Environmental Checker (IEC) to audit the results of the EM&A works carried out by the ET

 

Engineer or Engineer’s Representative (ER)

 

1.26            The term Engineer or Engineer’s Representative refers to the organisation responsible for overseeing the construction works of the Project undertaken by various Contractors in accordance with the specification and contractual requirements.  The ER should:

 

·         Monitor the Contractors’ compliance with contract specifications, including the implementation and operation of the environmental mitigation measures and their effectiveness

·         Monitor Contractors’, ET’s and IEC’s compliance with the requirements in the Environmental Permit (EP) and EM&A Manual

·         Facilitate ET’s implementation of the EM&A programme

·         Participate in joint site inspection by the ET and IEC

·         Oversee the implementation of the agreed Event / Action Plan in the event of any exceedance

·         Adhere to the procedures for carrying out complaint investigation

 

The Contractor

 

1.27            The term “Contractor” refers to all construction contractors and sub-contractors, working on site at any one time.  Besides reporting to the Engineer, the Contractor should:

 

·         Comply with the relevant contract conditions and specifications on environmental protection

·         Facilitate ET’s monitoring and site inspection activities

·         Participate in the site inspections by the ET and IEC, and undertake any corrective actions

·         Provide information / advice to the ET regarding works programme and activities which may contribute to the generation of adverse environmental impacts

·         Submit proposals on mitigation measures in case of exceedances of Action and Limit levels in accordance with the Event / Action Plans

·         Implement measures to reduce impact where Action and Limit levels are exceeded

·         Adhere to the procedures for carrying out complaint investigation

 

Independent Environmental Checker (IEC)

 

1.28            The Independent Environmental Checker (IEC) should not be in any way an associated body of the Contractor or the ET for the Project.  The IEC should be employed by the Project Proponent prior to the commencement of the construction of the Project.  The IEC should have at least 10 years’ experience in EM&A and have relevant professional qualifications, which shall include being an Accredited Monitoring Professional of the HKIEIA.  The appointment of IEC should be subject to the approval of EPD.  The IEC should:

 

·         Provide proactive advice to the ER and the Project Proponent on EM&A matters related to the project, independent from the management of construction works, but empowered to audit the environmental performance of construction

·         Review and audit all aspects of the EM&A programme implemented by the ET

·         Review and verify the monitoring data and all submissions in connection with the EP and EM&A Manual submitted by the ET

·         Arrange and conduct regular, at least monthly site inspections of the works during construction phase, and ad hoc inspections if significant environmental problems are identified

·         Check compliance with the agreed Event / Action Plan in the event of any exceedance

 

·         Check compliance with the procedures for carrying out complaint investigation

·         Check the effectiveness of corrective measures

·         Feedback audit results to ET by signing off relevant EM&A proforma

·         Check that the mitigation measures are effectively implemented

·         Report the works conducted, the findings, recommendation and improvement of the site inspections, after reviewing ET’s and Contractor’s works, and advices to the ER and Project Proponent on a monthly basis

 

Environmental Team (ET)

 

1.29            The ET shall not be in any way an associated body of the Contractor, and shall be employed by the Project Proponent to conduct the EM&A programme.  The ET should be managed by the ET Leader.  The ET Leader shall be a person who has at least 10 years’ experience in EM&A and has relevant professional qualifications, which shall include being an Accredited Monitoring Professional of the HKIEIA.  The appointment of ET Leader should be subject to the approval of EPD.  Suitably qualified staff should be included in the ET, and resources for the implementation of the EM&A programme should be allocated in time under the Contract, to enable fulfilment of the Project’s EM&A requirements as specified in the EM&A Manual during construction of the Project.  The ET shall report to the Project Proponent and the duties shall include:

 

·         Monitor and audit various environmental parameters as required in this EM&A Manual

·         Analyse the environmental monitoring and audit data, review the success of EM&A programme and the adequacy of mitigation measures implemented, confirm the validity of the EIA predictions and identify any adverse environmental impacts arising

·         Carry out regular site inspection to investigate and audit the Contractors' site practice, equipment/plant and work methodologies with respect to pollution control and environmental mitigation, and effect proactive action to pre-empt problems

·         Monitor compliance with conditions in the EP, environmental protection, pollution prevention and control regulations and contract specifications

·         Audit environmental conditions on site

·         Report on the environmental monitoring and audit results to EPD, the ER, the IEC and Contractor or their delegated representatives

·         Recommend suitable mitigation measures to the Contractor in the case of exceedance of Action and Limit levels in accordance with the Event and Action Plans

·         Liaise with the IEC on all environmental performance matters and timely submit all relevant EM&A proforma for approval by IEC

·         Advise the Contractor on environmental improvement, awareness, enhancement measures etc., on site

·         Adhere to the procedures for carrying out complaint investigation

 

1.30            Sufficient and suitably qualified professional and technical staff should be employed by the respective parties to ensure full compliance with their duties and responsibilities, as required under the EM&A programme during the construction phase of the Project.

 

Operation Phase

 

Drainage Services Department

 

1.31            DSD will be responsible for the operation of the Project and compliance with the conditions of the environmental permit during its operation.  Besides, DSD should:

 

·         Employ a Monitoring Team to undertake water quality monitoring, sediment monitoring, benthic survey, laboratory analysis and Whole Effluent Toxicity Tests (WETTs)

·         Employ an Environmental Consultant to analyze the monitoring results collected by the Monitoring Team

 

Monitoring Team

 

1.32            The Monitoring Team shall be managed by the Monitoring Team Leader to analyze the monitoring results.  The Monitoring Team Leader shall be a person who has a degree in Chemistry, Biochemistry or other environmental-related discipline from universities and has sufficient post-graduate experience in chemical tests and ecotoxicity tests.  Suitably qualified staff should be included in the Monitoring Team, and resources for the implementation of the monitoring programme should be allocated in time under the Contract, to enable fulfillment of the Project’s monitoring requirements as specified in the EM&A Manual during operation of the Project.  The Monitoring Team should:

 

·         Monitor various environmental parameters and conduct various chemical tests, ecotoxicity tests and benthic survey as required in this EM&A Manual

·         Report on the environmental monitoring results to EPD, DSD and the Environmental Consultant or their delegated representatives    

 

Environmental Consultant

 

1.33            The Environmental Consultant Team shall be managed by the Environmental Consultant Team Leader.  The Environmental Consultant Leader shall be a person who has sufficient knowledge and experience in health risk, ecological risk and ecotoxicity assessment.  Suitably qualified staff should be included in the Environmental Consultant Team, and resources for the implementation of the EM&A programme should be allocated in time under the Contract, to enable fulfillment of the Project’s EM&A requirements as specified in the EM&A Manual during operation of the Project.  The Environmental Consultant should:

 

·         Analyze monitoring results collected by the Monitoring Team

·         Prepare Water Quality Monitoring Report for each emergency discharge event

·         Prepare Human Health and Ecological Risk Evaluation Report based on the monitoring results collected to EPD and DSD for each set of operational phase monitoring

·         Prepare Sediment Quality Monitoring and Benthic Survey Report to EPD and DSD for each set of operational phase monitoring

·         Recommend suitable actions to DSD in case of exceedance of any health risk / ecological risk / ecotoxicity target level

 

Structure of the Report

 

1.34            Following this introductory section, the structure of the EM&A Manual is set out below:

 

·         Section 2 details the requirements for impact monitoring for dust during the construction phase and odour monitoring during the operation phase

·         Section 3 details the requirements for impact monitoring of noise during the construction phase

·         Section 4 details the requirements for baseline and impact monitoring for water quality during the operation phase

·         Section 5 details the requirements for the human health risk evaluation during the operation phase

·         Section 6 details the requirements for the ecological risk and ecotoxicity impact evaluation during the operation phase

·         Section 7 details the audit requirements with regard to waste management issues during construction phase

·         Section 8 details the audit requirements for terrestrial ecology during construction phase

·         Section 9 details the monitoring requirements for marine ecology during construction phase

·         Section 10 details monitoring requirements for fisheries during operation phase

·         Section 11 details landscape and visual monitoring during construction and operation phases

·         Section 12 details the monitoring requirements with regard to hazard to life in relation to potential hazardous installations during construction phase

·         Section 13 details the monitoring requirements with regard to cultural heritage during construction phase

·         Section 14 describes the scope of environmental auditing and the complaints handling procedure

·         Section 15 details the EM&A reporting requirements

 



[1] The objective of the ADF is to reduce the E. coli level in the CEPT effluent at SCISTW prior to discharge and hence facilitate early improvement to beach water quality.  A separate EIA study - Agreement No. CE 7/2005 (EP) HATS EIA Study for the Provision of Disinfection Facilities at Stonecutters Island STW - Investigation was approved by EPD on 8 November 2007 (Approved EIA Register No.: AEIAR-113/2007). The ADF EIA Report is available at http://www.epd.gov.hk/eia/register/report/eiareport/eia_1342007/index.htm