1. BACKGROUND

1.1 An application (No. ESB-076/2001) for an Environmental Impact Assessment (EIA) study brief under section 5(1) of the Environmental Impact Assessment Ordinance (EIAO) was submitted by the captioned Applicant on 21 May 2001 with a project profile (No. PP-131/2001) on the captioned project (the Project Profile).

1.2 To meet the demands of both the existing and future developments in the catchment, the Applicant proposes to upgrade the existing Tai Po Sewage Treatment Works (STW) to provide additional sewage treatment capacity from the present daily average flows of 88,000 m3/day to 130,000 m3/day. The proposed upgrading works shall take place within the existing Tai Po STW site. The key elements of the project are to:

(i) modify and expand the existing secondary treatment process, including construction of additional sewage treatment and sludge treatment process units;
(ii) upgrade the sewage treatment process by adding the ultra-violet irradiation effluent disinfection facilities; and
(iii) demolition of part of the existing treatment units.

The project is a Designated Project under the EIAO by virtue of item F.1 of the Schedule 2, Part I of the EIAO, i.e. sewage treatment works with an installed capacity of more than 15,000 m3 per day.

1.3 Drawing No. DCM/2001/035 attached to the Project Profile indicates the project location of Tai Po Sewage Treatment Works.

1.4 Pursuant to section 5(7)(a) of the EIAO, the Director of Environmental Protection (the Director) issues this EIA study brief to the Applicant to carry out an EIA study for the project.

1.5 The purpose of this EIA study is to provide information on the nature and extent of environmental impacts arising from the construction and operation of the proposed project and related activities taking place concurrently. This information will contribute to decisions by the Director on:

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

(ii) the conditions and requirements for the detailed design, construction and operation of the proposed project to mitigate against adverse environmental consequences wherever practicable; and

(iii) the acceptability of residual impacts after the proposed mitigation measures is implemented.

2. OBJECTIVES OF THE EIA STUDY

2.1 The objectives of the EIA study are as follows:

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

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

(iii) to provide information on the consideration of alternatives to avoid and minimize the environmental impacts, in particular on the Tolo Harbour and Channel Water Control Zone and the Victoria Harbour Water Control Zone and to compare the environmental benefits and dis-benefits of each of the different options and to provide reasons for selecting a preferred option and to describe the part environmental factors played in the selection;

(iv) to identify and quantify emission sources and determine the significance of impacts on sensitive receivers and potential affected uses;

(v) to identify any potential impacts from point and non-point pollution sources on the identified water systems and sensitive receivers during the construction and operation stages;

(vi) to identify and quantify waste management requirements and to propose measures to mitigate or prevent impacts;

(vii) to evaluate the degree of risk of the landfill gas associated with the proposed project and to propose measures to mitigate the impacts,

(viii) to propose the provision of mitigation measures so as to minimize pollution, environmental disturbance and nuisance during construction and operation of the project;

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

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

(x) to investigate the extent of the secondary environmental impacts that may arise from the proposed mitigation measures and to identify constraints associated with the mitigation measures recommended in the EIA study, as well as the provision of any necessary modification; and

(xi) to design and specify environmental monitoring and audit requirements to ensure the implementation and the effectiveness of the environmental protection and pollution control measures.

3. DETAILED REQUIREMENTS OF THE EIA STUDY

The Purpose

3.1 The purpose of this study brief is to scope the key issues of the EIA study. The Applicant has to demonstrate in the EIA report that the criteria in the relevant sections of the Technical Memorandum on the EIA Process of the EIAO (hereinafter referred to as the TM) are fully complied with.

3.2 The Applicant shall state clearly the purpose of the project, in particular the problems(s) or opportunity(s) that the project is intended to solve or satisfy, and what is to be achieved by carrying out the project.

The Scope

3.3 The scope of this EIA study covers the proposed project mentioned in section 1.2 above. The EIA study shall address any key issues described below, together with any key issues identified during the course of the study and the cumulative environmental impacts of the Project, through interaction or in combination with other existing, committed and planned developments in the vicinity of the Project:

(i) the air quality impacts arising from the construction, decommissioning/demolition, and operation of the Project;

(ii) the water quality impacts arising from the construction, decommissioning/demolition, and operation of the Project, in particular the impacts due to increased loading on Victoria Harbour via the Kai Tak Nullah Outfall and the impacts on Tolo Harbour and the seawater intake of Tai Po Salt Water Pumping Station arising from emergency discharge of sewage during construction and operation of the Project;

(iii) the waste management for the construction and operation of the Project; and

(iv) the landfill gas hazards associated with the proposed project.

Consideration of Alternatives

3.4 When preparing the EIA report in accordance with the technical requirements below and the TM, the Applicant shall consider different options and means (such as alternative detail designs, alternative construction and operation methods, etc.) with a view to avoiding or minimizing the potential environmental impacts of the proposed project. The Applicant shall compare the environmental impacts as well as the environmental benefits and dis-benefits of each of the different options and provide reasons for selecting the final preferred option including the environmental factors played in the selection.

Technical Requirements

3.5 The Applicant shall conduct the EIA study to address all environmental aspects of the activities as described in the scope as set out above. The EIA study shall include the following technical requirements on specific impacts.

3.5.1 Air Quality Impact

General Requirement

3.5.1.1 The Applicant shall follow the criteria and guidelines for evaluating and assessing air quality impact as stated in section 1 of Annex 4 and Annex 12 of the TM respectively.

3.5.1.2 The assessment area for air quality impact shall generally be defined by a distance of 500 m from the boundary of the project site, yet it may be extended depending on the circumstances and the scale of the project.

3.5.1.3 The Applicant shall assess the air pollutant concentrations in accordance with the latest set of Guidelines for Local-Scale Air Quality Assessment Using Models issued by the Environmental Protection Department, HKSAR. (ref.: EPD's home page under items for Air - http://www.info.gov.hk/epd) or other methods as approved by the Director.

Impact Assessment

3.5.1.4 The air quality assessment shall include the following:

Background and analysis of activities

(i) Provide background information relating to air quality issues relevant to the project, e.g. description of the types of activities of the project.

(ii) Give an account, where appropriate, of the consideration/measures that had been taken into consideration in the planning of the project to abate the air pollution impact. That is, the Applicant should consider alternative construction methods/phasing programmes and alternative modes of operation to minimize the constructional and operational air quality impacts respectively.

(iii) Present the background air quality levels in the assessment area for the purpose of evaluating the cumulative constructional and operational air quality impacts.

Identification of Air Sensitive Receivers (ASRs) and examination of emission/dispersion characteristics

(iv) Identify and describe representative existing and planned/committed ASRs that would likely be affected by the project. The Applicant shall select the assessment points of the identified ASRs such that they represent the worst impact point of these ASRs. A map showing the location and a description including the name of the buildings, their uses and height of the selected assessment points shall be given. The separation distances of these ASRs from the nearest emission sources should also be given. For phased development, the Applicant should review the development programme to take into consideration the construction stages so as to include occupiers of early phases as ASRs if they may be affected by works at later phases.

(v) Provide an exhaustive list of air pollutant emission sources, including any nearby emission sources which are likely to have impact on the project. Examples of constructional stage emission sources include stock piling, blasting, concrete batching and vehicular movements on unpaved haul roads on site, etc.. Examples of operational stage emission sources include emission of odour from the proposed STW, etc.. Confirmation of the validity of the assumptions and the magnitude of the activities (e.g. volume of construction materials handled) shall be obtained from the relevant government/authorities and documented.

Construction Dust Impact

(vi) The Applicant shall follow the requirements of the Air Pollution Control (Construction Dust) Regulation in dust control to ensure construction dust impacts are controlled within the relevant standards as stipulated in section 1 of Annex 4 of the TM. A monitoring and audit program during construction stage shall be justified to verify the effectiveness of the control measures and to ensure that the construction dust levels be brought under control.

(vii) If the Applicant anticipates a significant construction dust impact that will likely cause exceedance of the recommended limits in the TM at the ASRs despite incorporation of the dust control measures stated in (vi) above, a quantitative assessment should be carried out to evaluate the construction dust impact at the identified ASRs based on the emission strength of the emission sources identified in (v) above. The Applicant shall follow (ix) to (xiii) below when carrying out the quantitative assessment.

Operational Air Quality Impact (Odour)

(viii) The Applicant shall calculate the expected air pollutant concentrations at the identified ASRs. Calculations for the expected impact shall be based on an assumed reasonably worst case scenario. The evaluation shall be based on the strength of the emission sources identified in (v) above. The Applicant shall follow (ix) to (xiii) below when carrying out the quantitative assessment.

Quantitative Assessment Methodology

(ix) The Applicant shall apply the general principles enunciated in the modeling guidelines (3.5.1.3 above) while making allowance for the specific characteristic of each project. This specific methodology must be documented in such level of details (preferably with tables and diagrams) to allow the readers of the assessment report to grasp how the model is set up to simulate the situation at hand without referring to the model input files. Details of the calculation of the emission rates of air pollutants for input to the modeling shall be presented in the report. The Applicant must ensure consistency between the text description and the model files at every stage of submission. Prior agreement of the general methodology between the Applicant and the Director is advised.

(x) The Applicant shall, based on the nature of the activities analysed in (v) above, identify the key/representative air pollutant parameters (types of pollutants and the averaging time concentration) to be evaluated and provide explanation for choosing these parameters for the assessment of the impact of the project.

(xi) The Applicant shall calculate the cumulative air quality impact at the identified ASRs and compare these results against the criteria set out in section 1 of Annex 4 in the TM. The predicted air quality impacts (both unmitigated and mitigated) shall be presented in the form of summary table and pollution contours, for comparison with relevant air quality standards and examination of the land use implications of these impacts. Plans of suitable scale should be used for presentation of pollution contour for determining buffer distances required.

Mitigating Measures for Non-compliance

(xii) The Applicant shall propose remedies and mitigating measures where the predicted air quality impact exceeds the criteria set in section 1 of Annex 4 in the TM. These measures and any constraints on future land use planning shall be agreed with the relevant government departments/authorities and documented. The Applicant shall demonstrate quantitatively that the resultant impacts after incorporation of proposed mitigating measures will comply with the criteria stipulated in section 1 of Annex 4 in the TM.

Submission of Model Files

(xiii) All input and output file(s) of the model run(s) shall be submitted to the Director in electronic format.

3.5.2 Noise Impact

3.5.2.1 The EIA shall provide a general description of any noise control measures during both the construction and operation of the Project. Unless the Applicant confirms in the EIA report that there is no existing and planned noise sensitive receiver identified within 300m from the project boundary and the construction and operational noise generated from the Project will comply with the standards stipulated in the TM with noise control measures in place, a noise impact assessment for both construction and operation stage shall be required. In that event, the Director shall be approached for detailed requirements for the assessment.

3.5.3 Water Quality Impact

3.5.3.1 The Applicant shall follow the criteria and guidelines for evaluating and assessing water pollution as stated in Annexes 6 and 14 of the TM, respectively.

3.5.3.2 The "Assessment Area" for the purpose of this water quality assessment shall cover all relevant sensitive receivers within the Victoria Harbour Water Control Zone (WCZ) and Tolo Harbour and Channel WCZ.

3.5.3.3 The Applicant shall identify and analyze in the assessment all physical, chemical and biological disruptions of either marine water and/or fresh water, and/or ground water systems arising from construction and operation of the project (including the impacts arising from emergency discharge of sewage).

3.5.3.4 The Applicant shall include the following in the water quality impact assessment:

(i) Collection and review of background information on the existing water system(s).

(ii) Characterization of water quality based on existing information or site surveys/tests as appropriate.

(iii) Identification and analysis of all existing and planned future activities and beneficial uses related to the water system(s) and identification of all water sensitive receivers.

(iv) Identification of pertinent water quality objectives and establishment of other appropriate water quality criteria or standards for the water system(s) and all the sensitive receivers.

(v) Review the specific construction methods and operation of the proposed project. Identification of any alteration of watercourses.

(vi) Identification, analysis and quantification of all existing and likely future water pollution sources, including point discharges and non-point sources to surface water runoff. Field investigation and laboratory tests shall be conducted as appropriate. Establishment and provision of an emission inventory on the quantities and characteristics of all these pollution sources.

(vii) Prediction and quantification, by mathematical modeling, of impacts on the water system(s) and the sensitive receivers, including the portals and catchwaters of the water gathering ground, due to those alterations and changes identified in (v) above and the pollution sources identified in (vi) above. Possible impacts include changes in hydrology, flow regime, sediment erosion or deposition, water and sediment quality and the effects on the aquatic organism due to such changes. The prediction shall include possible different construction stages or sequences, and different operation stages. The water quality model used shall comply with the following specification:

Modeling Software General

(a) The modeling software shall be fully 3-dimensional capable of accurately simulating the stratified condition, salinity transport, and effect of wind and tide within the model area.

(b) The modeling software shall consist of hydrodynamic, water quality and particle dispersion modules. The hydrodynamic and water quality modules shall have been proven with successful applications locally and overseas.

(c) The hydrodynamic and water quality modules shall be strictly mass conserved at all levels.

Model Details - Calibration & Validation

(d) No field data collection is required for model calibration for this study. However, the models shall be properly calibrated and validated before its use in this study in the area including the Victoria Harbour, Western Buffer, Eastern Buffer, Southern and Tolo Harbour and Channel Water Control Zones, defined under the Water Pollution Control Ordinance, with the field data collected by:

• Hydraulic and Water Quality Studies in Victoria Harbour (1987)
• Port and Airport Development Strategy - Enhancement of WAHMO Mathematical Models (1990)
• Strategic Sewage Disposal Scheme Stage II - Oceanic Outfall, Oceanographic Surveys and Modelling (1992)
• Update on Cumulative Water Quality and Hydrological Effect of Coastal Developments and Upgrading of Assessment Tool (1998)
• EPD's routine monitoring data
• Tidal data from HK Observatory, Macau and relevant Mainland Authorities.

(e) Tidal data shall be calibrated and validated in both frequency and time domain manner.

(f) For the purpose of calibration and validation, the model shall run for not less than 15 days of real sequence of tide (excluding model spin up) in both dry and wet seasons with due consideration of the time required to establish initial conditions.

(g) In general, the hydrodynamic models shall be calibrated to the following criteria:

Model Details - Simulation

(h) The water quality modeling results shall be qualitatively explainable, and any identifiable trend and variations in water quality shall be reproduced by the model. The water quality model shall simulate and take account of the interaction of dissolved oxygen, phytoplankton, organic and inorganic nitrogen, phosphorus, silicate, BOD, temperature, suspended solids, air-water exchange, contaminant release of dredged and disposed material, and benthic processes. It shall also simulate salinity and E. coli. Salinity results simulated by hydrodynamic models and water quality models shall be demonstrated to be consistent.

(i) The models shall at least cover the Ma Wan Channel, Cheung Chau, East Lamma Channel, Victoria Harbour, Tathong Channel Nine Pin Islands, Po Toi Islands, and the Tolo Harbour and Tolo Channel to incorporate all major influences on hydrodynamic and water quality.

(j) In general, grid size at the area affected by the project shall be less than 400 m in open waters and less than 75m around sensitive receivers. The grid schematisation shall be agreed with the Director. All models shall either be dynamically linked to a far field model or form part of a larger model by gradual grid refinement.

Modeling Assessment

(k) Scenarios to be assessed shall cover all phases of development being considered. Corresponding pollution load, bathymetry and coastline shall be adopted in the model set up.

(l) Hydrodynamic and water quality models shall be run for (with proper model spin up) at least a real sequence of 15 days spring-neap tidal cycle in both dry season and wet season.

(m) The water quality model shall run for a complete year incorporating monthly variations in Pearl River discharges, solar radiation, water temperature and wind velocity in the operation phase. Construction phase impacts may be assessed by simulating typical spring-neap cycles in the dry and wet seasons.

(n) The results shall be assessed for compliance of Water Quality Objectives. Daily sedimentation rate shall be computed and its ecological impact shall be assessed.

(o) Assess the impact on all sensitive receivers including the application of bacterial dispersion module.

(p) All modelling input data and results shall be submitted in digital media to the Director.

Waste Water and Non-point Source Pollution

(viii) Analysis on the provision and adequacy of existing and planned future facilities to reduce pollution arising from the non-point sources identified in (vi).

(ix) Proposal of effective and practicable upgrading or provision, water pollution prevention and mitigation measures to be implemented during the construction, operation stages so as reduce the water quality impacts to within acceptable levels of standards. Requirements to be incorporated in the project contract document shall also be proposed.

(x) Best management practices to reduce storm water and non-point source pollution shall be investigated and proposed as appropriate. Attention shall be made to the water quality control and mitigation measures recommended in the ProPECC Note PN1/94 entitled "Construction Site Drainage."

(xi) Evaluation and quantification of residual impacts on the water system(s) and the sensitive receivers with regard to the appropriate water quality criteria, standards or guidelines.

Protection of Tolo Harbour and Channel Water Control Zone and the Seawater Intake of Tai Po Salt Water Pumping Station

(xii) Derive an emergency contingency plan for the construction and operational phase of the project with the aim to contain and remove all accidental spillage in short notice and to prevent and or to minimize the quantities of contaminants from reaching Tolo Harbour and seawater intake of the Tai Po Salt Water Pumping Station.

(xiii) The Applicant shall assess the need for routine flow monitoring system, including details like the locations of the monitoring points and the frequency of monitoring, in order to ensure early detection of any major leakage.

3.5.4 Waste Management Implications

3.5.4.1 The Applicant shall follow the criteria and guidelines for evaluating and assessing waste management implications as stated in Annexes 7 and 15 of the TM, respectively.

3.5.4.2 The assessment of waste management implications shall cover the following:

(i) Analysis of Activities and Waste Generation

The Applicant shall identify the quantity, quality and timing of the waste arising as a result of the construction and operation activities, based on the sequence and duration of these activities.

(ii) Proposal for Waste Management

(a) Prior to considering the disposal options for various types of wastes, opportunities for reducing waste generation and on-site or off-site re-use shall be fully evaluated. Measures which can be taken in the planning and design stages e.g. by modifying the design approach and in the construction stage for maximizing waste reduction shall be separately considered.

(b) After taking into account all the opportunities for reducing waste generation and maximizing re-use, the Applicant shall estimate the types and quantities of the wastes required to be disposed of as a consequence and describe the disposal options for each type of waste in detail. The disposal options for each type of wastes shall take into account the result of the assessment in (c) below.

(c) The impact caused by handling (including labeling, packaging & storage), collection, and disposal of wastes shall be addressed in detail and appropriate mitigation measures proposed. This assessment shall cover the following areas:
- potential hazard;
- air and odour emissions;
- noise;
- wastewater discharge; and
- public transport.

3.5.5 Landfill Gas Hazards Assessment

3.5.5.1 The Applicant shall follow the guidelines for evaluating and assessing landfill gas hazards as stated in Annexes 7 and 19 of the TM, respectively.

3.5.5.2 The landfill gas hazards assessment shall include a qualitative risk assessment and landfill gas precautionary/protection design. Specifically, the assessment shall include the following tasks:

(a) review of background information and studies related to Shuen Wan Landfill;

(b) identification of the nature and extent of the sources, including the likely concentrations/amounts of hazardous emissions which might have the potential for impacts on the proposed facilities;

(c) identification of possible pathways through the ground, underground cavities, utilities or groundwater, and the nature of these pathways through which hazardous emissions must traverse if they were to reach the proposed facilities;

(d) identification of the potential targets associated with the proposed facilities which are sensitive to the impacts of the hazardous emissions;

(e) qualitative assessment on the degrees of risk which the hazardous emissions may pose to the target for each of the source-pathway-target combinations;

(f) design of suitable level of precautionary measures for the construction of the proposed facilities and the types of protection measures for their safe operations, if needed; and

(g) identification of monitoring requirement for assessing the adequacy and performance of the implemented protection measures.

4. ENVIRONMENTAL MONITORING & AUDIT (EM&A) REQUIREMENTS

4.1 The Applicant shall identify in the EIA study whether there is any need for EM&A activities during the construction and operational phases of the project and, if affirmative, to define the scope of the EM&A requirements for the project in the EIA study.

4.2 Subject to the confirmation of the EIA study findings, the Applicant shall comply with the requirements as stipulated in Annex 21 of the TM.

4.3 The Applicant shall prepare a project implementation schedule (in the form of a checklist) containing all the EIA study recommendations and mitigation measures with reference to the implementation programme.

5. SUMMARY OF ENVIRONMENTAL OUTCOMES

5.1 The EIA report shall contain a summary of the key environmental outcomes arising from the EIA study, including the population and environmentally sensitive areas protected, environmentally friendly designs recommended, key environmental problems avoided, and environmental benefits of environmental protection measures recommended.

6. DURATION OF VALIDITY

6.1 This EIA study brief is valid for 24 months after the date of issue. If the EIA study does not commence within this period, the Applicant shall apply to the Director for another EIA study brief afresh before commencement of the EIA study.

7. REPORT REQUIREMENTS

7.1 In preparing the EIA report, the Applicant shall refer to Annex 11 of the TM for the contents of an EIA report. The Applicant shall also refer to Annex 20 of the TM which stipulates the guidelines for the review of an EIA report.

7.2 The Applicant shall supply the Director with the following number of copies of the EIA report and the executive summary:

(i) 40 copies of the EIA report in English and 80 copies of the executive summary (each bilingual in both English and Chinese) as required under section 6(2) of the EIAO to be supplied at the time of application for approval of the EIA report.

(ii) when necessary, addendum to the EIA report and the executive summary submitted in 7.2 (i) above as required under section 7(1) of the EIAO, to be supplied upon advice by the Director for public inspection.

(iii) 20 copies of the EIA report in English and 50 copies of the executive summary (each bilingual in both English and Chinese) with or without Addendum as required under section 7(5) of the EIAO, to be supplied upon advice by the Director for consultation with the Advisory Council on the Environment.

7.3 In addition, to facilitate the public inspection of the EIA Report via the EIAO Internet Website, the Applicant shall provide electronic copies of both the EIA Report and the Executive Summary Report prepared in Hyper Text Markup Language (HTML) (version 4.0 or later) and in Portable Document Format (PDF version 4.0 or later), unless otherwise agreed by the Director. For the HTML version, a content page capable of providing hyperlink to each section and sub-section of the EIA Report and the Executive Summary Report shall be included in the beginning of the document. Hyperlinks to all figures, drawings and tables in the EIA report and executive summary shall be provided in the main text from where the respective references are made. All graphics in the report shall be in interlaced GIF format unless otherwise agreed by the Director.

7.4 The electronic copies of the EIA report and the Executive Summary shall be submitted to the Director at the time of application for approval of the EIA Report.

7.5 When the EIA Report and the Executive Summary are made available for public inspection under section 7(1) of the EIAO, the content of the electronic copies of the EIA Report and the Executive Summary must be the same as the hard copies an the Director shall be provided with the most updated electronic copies.

7.6 To promote environmentally friendly and efficient dissemination of information, both hardcopies and electronic copies of future EM&A reports recommended by the EIA study shall be required and their format shall be agreed by the Director.

8. OTHER PROCEDURAL REQUIREMENTS

8.1 During the EIA study, if there is any change in the name of the Applicant for this EIA study brief, the Applicant mentioned in this study brief must notify the Director immediately.

8.2 If there is any key change in the scope of the project mentioned in sections 1.2 and 1.3 of this EIA study brief and in Project Profile (No. PP-131/2001), the Applicant must seek confirmation from the Director in writing on whether or not the scope of issues covered by this EIA study brief can still cover the key changes, and the additional issues, if any, that the EIA study must also address. If the changes to the project fundamentally alter the key scope of the EIA study brief, the Applicant shall apply to the Director for a fresh EIA study brief.

--- END OF EIA STUDY BRIEF ---

June 2001
Environmental Assessment and Noise Division,
Environmental Protection Department