9.                  TABLE OF CONTENTS

9.                  Page

9.                   

9.                  1.   INTRODUCTION   1

9.                  Background   1

9.                  The Assignment   1

9.                  Purpose and Scope of IAR   2

9.                  Assessment Area   3

9.                  Organisation of the Report   3

9.                  2.   PROJECT DESCRIPTION   4

9.                  Introduction   4

9.                  Project Programme   4

9.                  Construction and Operational Activities   4

9.                  Need of the Project   4

9.                  Consideration of Alternative Options   4

9.                  3.   AIR QUALITY   6

9.                  Introduction   6

9.                  Environmental Legislation and Standards   6

9.                  Baseline Conditions   6

9.                  Air Sensitive Receivers   6

9.                  Assessment Methodology & Criteria   6

9.                  Identification of Environmental Impacts   6

9.                  Initial Evaluation of Impacts   6

9.                  Mitigation Measures   6

9.                  Further Studies   6

9.                  Conclusion   6

9.                  4.   NOISE IMPACT   7

9.                  111233ofOFkey issuesKEY ISSUES44444455557676767676PROGRAMMEprogramme1110111011101211121112111.   INTRODUCTION   1

9.                  Background   1

9.                  The Assignment   1

9.                  Objectives of EIA Study   2

9.                  Assessment Area   3

9.                  Organisation of the Report   3

9.                  2.   UNDERSTANDING of OBJECTIVES & KEY ISSUES   4

9.                  Understanding of Objectives   4

9.                  Key Issues   4

9.                  Noise Impact   4

9.                  Ecological Impacts   4

9.                  Cultural Heritage   4

9.                  Landscape & Visual   4

9.                  Water Quality   5

9.                  Waste Management   5

9.                  3.   APPROACH AND METHODOLOGY   6

9.                  Introduction   6

9.                  Inception Stage   6

9.                  Baseline Stage   6

9.                  Detailed Assessment Stage   6

9.                  4.   STUDY programme   10

9.                  Works Programme   10

9.                  Deliverable and Meeting Schedule   10

9.                  5.   STUDY TEAM   11

9.                  Study Team Organisation   11

9.                  Key Team Members   11

9.                   

9.                     List of Tables

9.                   

9.                  Table 4.1      Key Deliverables Submission   111010

9.                   

9.                  List of Figures

9.                   

9.                  Figure 1.1a   Location of Project Works (Sheet 1 of 2)

9.                  Figure 1.1b   Location of Project Works (Sheet 2 of 2)

9.                  Figure 1.2   Layout Plan of Siu Ho Wan WTW Extension

9.                  Figure 2.1   Key Environmental Issues – Air, Noise and Visually Sensitive Receivers

9.                  Figure 2.2   Key Environmental Issues – Ecology, Water and Cultural Heritage

9.                  Figure 2.3   Siu Hon Wan Water Treatment Works – Hazards Consultation Zone

9.                  Figure 4.1   Study Programme

9.                  Figure 5.1   Organisation Chart

9.                   

9.                  Appendices

9.                   

9.                  Appendix A   Curriculum Vitaes

9.                   

9.                  INTRODUCTIONHAZARD TO LIFE

9.1              BackgroundIntroduction

9.1.1        The existing Siu Ho Wan Water Treatment Works (hereinafter referred to as SHWiu Ho Wan WTW) and the associated raw water and treated water transfer and distribution systems were commissioned in 1997 to provide treated water capacity of 150,000 m3/day.  It provided treated water to the Hong Kong International Airport at Chek Lap Kok and the initial phases of North Lantau New Town and Discovery BayThis sSection investigates the issue of Hazard to Life associated with chlorine, which is used as the major disinfection agent in theSiu Ho Wan wWater tTreatment wWorks.

9.1.1          With reference to the Section 3.7 of the EIA Study Brief 3.7, chlorine hazards during construction phase and operation phase will be investigated.  For hazards during construction phase, the additional hazards initiated by construction activities will be identified by systematic method (i.e. Hazard and Operability (HAZOP) Study).  For operation phase, hazards associated with chlorine will be assessed if and only if there is an increase of storage and on-site transport of chlorine.

 

9.2              Rationale of the HAZOP Study

 

9.2.1        According to Section 1.2 (i) of the EIA Study Brief, the Project comprises, inter alias, the extension of Siu Ho Wan WTW from the capacity of 150,000 m3/day to 300,000 m3/day, with an option for further uprating to 350,000 m3/day. Based on a review update on the ultimate water demand at this stage, the extension work would only comprise of uprating to 300,000 m3/day. No further uprating to the capacity of 350,000 m3/day is required for this Project.

 

9.2.2        For the investigation study under the agreement, options selection for the appropriate water treatment process has been conducted by the Consultants. The recommended water treatment process consists of the following:

-         Removal of odour by pre-ozonation;

-         Pre-treatment of manganese by potassium permanganate;

-         Sedimentation by installation of tube settlers in clarifiers;

-         Primary disinfection by intermediate ozonation;

-         Filtration by installation of dual media filters (GAC media and fine sand);

-         Post chlorination for residual chlorine requirement.

 

9.2.3        In the original water treatment process, chlorine was proposed for oxidation of impurities and disinfection. The allowable storage of chlorine in the existing Siu Ho Wan WTW compound at a capacity of up to 73 tonnes which was endorsed by Co-ordinating Committee on Land-Use Planning and Control relating to Potentially Hazardous Installations (CCPHI) on 30.5.1992 during the Stage I WTW, has already duly taken into account future extension of the WTW up to 300 MLD i.e. 300,000 m3/day.  

 

9.2.4        The recommended water treatment process as endorsed by WSD in February 2004 adopts "ozone" for primary disinfection with the addition of potassium permanganate to remove manganese and BAC filter to remove ammonia for the Siu Ho Wan WTW extension.  As such, no chlorine would be required for the proposed water treatment process under normal condition except for post chlorination. Chlorine dose would not exceed the designed dosing capacity of the WTW as defined in the Steering Group Report on Hazard Assessment, Planning Study and Action Plan endorsed by CCPHI in May 1992.  Hence, there will be no increase of storage and on-site transport of chlorine to that of the allowable storage capacity for the Siu Ho Wan WTW. With reference to the Options Selection Report, the chlorine consumption is anticipated to return to the designed level of the WTW or below.  Also, the Final Adoptive Report (dated 15 September 2003) gave a full justification to explain that there would be no increase of chlorine consumption after Siu Ho Wan WTW is extended.  Executive summary of Option Selection Report and relevant pages of the Final Adoptive Report is attached in Appendix 9.2 and 9.3 respectively.  Therefore, proposed water treatment process in the extended WTW would induce no increase of chlorine hazard in terms of storage or number of deliveries.  As a result, the hazard assessment for the operation phase of Siu Ho Wan WTW extension is not required in the EIA stage and only a HAZOP study was conducted in this EIA Sstudy.

 

9.3              Risk Guidelines

9.3.1        As stipulated in Annex 4 of the Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM), the societal risk guidelines for acceptable risk levels has included the ALARP region, which required that risk within ALARP region should be mitigated to “As Low As Reasonably Practicable”. In comparing with the “CCPHI Interim Guideline for Acceptable Societal Risk” (IRG) adopted for the Hazard Assessment, no ALARP region was adopted for that study. In reviewing the societal risk associated with the water treatment works assessed in the Hazard Assessment, some of the scenarios, with the assumptions of implementing several mitigation measures, would lie within one to two orders of magnitude below the IRG, which is the ALARP region of the societal risk guideline stipulated in the TM.

 

9.3.2        Referring to the recommendations from the Hazard Assessment, it concluded that any risk within two orders of magnitude of the IRG should be mitigated as low as reasonably practical. Also, it mentioned that any risk at two orders of magnitude below the IRG may, in ALARP terms, be considered negligible. Therefore, the Hazard Assessment noted it is unlikely that any further mitigation measures for the works may be justified and the site may be considered suitable from the perspective of public safety.

 

9.3.3       The Hazard Assessment also concluded that the site selected for the WTW was suitable in terms of the Interim Risk Guidelines with the implementation of the following risk mitigation measures:

·          Use reinforced concrete panels in the construction of the chlorine drum store

·          Adopt “Route 2” (transport liquid chlorine by sea to Refuse Transfer Station (RTS) near the WTW at Siu Ho Wan and the remaining short distance to the plant by road) as the primary chlorine transportation route

·          Restrict the chlorine delivery using the seawall at or near the RTS at Siu Ho Wan to the weekend or only transport of up to 12 drums by sea to the RTS seawall at any one time with only 26 deliveries per year

·          Prohibit overnight chlorine drums storage at the seawall

·          Institute a 30m cordon around the chlorine unloading point during deliveries and temporary storage within a secure area surrounded by a steel barrier  

 

9.3.4       The Hazard Assessment also recommended a 1000 metre radius centred on (excluding land 50m in altitude above) the Chlorine Building as Consultation Zone for Siu Ho Wan WTW.  Moreover, land-use restrictions at Areas 7, 9 and 10 in the Recommended Outline Development Plan (RODP) for the North Lantau Development were recommended in the Hazard Assessment to ensure the compliance of Interim Risk Guidelines.

 

9.3.5       As confirmed with WSD on the implementation of mitigation measures stated in Section 9.3.3, the establishment of consultation zone for Siu Ho Wan WTW and the implementation of land-use restrictions in Section 9.3.4 with no change in land-use for the restricted areas, the societal risk associated with the Siu Ho Wan WTW would have been no change from that previously assessed in the Hazard Assessment.

 

 

9.4              Approach of HAZOP Study

9.4.1        The HAZOP Study was carried out in several stages:

 

·      Define the scope of the Study

·      Select the HAZOP Study Team

·      Prepare for the HAZOP Study MeetingHAZOP

·      Execute HAZOP Study Meeting

·      Report the Study Results

 

 

 

Define the scope of the Study

 

9.4.2        The scope of the Study is in line with the EIA Study Brief, which is:

 

i)                    Identify additional hazards initiated by construction activities which may increase the risk of chlorine accidents during storage, handling, transport

ii)                   Recommend risk mitigation measures for implementation during construction phase

 

Select the HAZOP Study Team

 

9.4.3        The team members were selected in a manner that could ensure the Study Tteam would have sufficient knowledge of the following items:

 

a)                  Design of the existing and future extended Siu Ho Wan WTW

b)                 Daily operation of the existing Siu Ho Wan WTW

c)                  Maintenance and repair works at existing Siu Ho Wan WTW

d)                 Chemical properties of chemicals/compounds involved in operation and extension work of Siu Ho Wan WTW

e)                  Safety issues encountered at the existing Siu Ho Wan WTW and future extension works   

f)                   Environmental issues encountered in future Siu Ho Wan WTW extension works

 

 

 

 

 

 

Collect necessary dataPrepare for the HAZOP Study Meeting

 

9.4.4        Prior to the HAZOP Study meeting, the following information were gatheredThe preparation work prior to the HAZOP Study Meeting involved:

 

Collect useful information

 

Information collected prior to the Study Meeting included the followings:

·          Locations of the chlorine storage area and chlorine pipework

·          Chlorine delivery procedures and travel route of Cchlorine Ddelivery Ttruck on site

·          Chlorine handling and emergency procedures

·          ExpectedPossible construction activities and corresponding plants/equipment involved in the extension works

·          Material Safety Data Sheet (MSDS) of chemicals and material encountered/to be encountered during the Wwater Ttreatment Wworks operation and extension construction worksactivities

 

                Convert the collected information into a suitable form

 

In order to provide concise and easy-understanding information to the Study Team members, the collected information were converted into layout plan and summary table.

 

Plan the Study Meeting sequence

 

Prior to the sStudy mMeeting, a Study Meeting sequence was prepared to ensure the Study Meeting could proceed smoothly and systematically.  During the preparative work, it was planned that the Study Meeting would be conducted in a construction activity-based sequence.  That is, all the expectedpossible extension construction activities and plants/equipment involved would be discussed in turn to identify possible hazards and mitigation measures.   

 

Arrange Study Meeting

 

After necessary information was obtained and Study Meeting sequence was planned, all the Study Team members were invited to attend the Study Meeting.  In the meantime, obtained information (in form of layout plan and summary table) and Study Meeting sequence were sent to the Study Team members for their preparation before the meeting.

 

Execute HAZOP Study Meeting

 

One HAZOP Study Meeting session was carried out on 5 February 2004.  Representatives from WSD, M&E and MEMCL participated in the Study Meeting.  The items discussed were recorded during the Study Meeting.

 

Report the Study Results

 

Key findings in the Study including causes of the hazard imitatinginitiating events and the corresponding mitigation measures are presented in the following Sectionsparagraphs.

 

9.5              Description of Site Conditions and Possible Construction Activities
Description of Site Conditions and Possible Construction Activities

9.5.1        The Siu Ho Wan Water Treatment Works is located in Area 4 on the Siu Ho Wan Layout Plan No.L/I-SHW/1Tai Ho Wan Area 4, with area about 5.8ha.  For the HAZOP Study, locations of chlorine-related facilities and travel route of chlorine delivery truck in the existing Siu Ho Wan WTW compound are of interest.  A layout plan showing locations of Chlorine Building, chlorine piepeworks and chlorine delivery truck travel route is given in Figure 9.1.

 

9.5.2        Description of the Project has been given in Section 2.  As agreed in the HAZOP Study Meeting, only construction activities inside the Siu Ho Wan WTW compound were discussed in the HAZOP Study because construction works outside the Siu Ho Wan WTW compound were considered unlikely to initiate additional hazards related to chlorine.  The construction activities and corresponding plants/equipment discussed in the Study Meeting were listed in Table 9.1.

 

Table 9.1 Construction Activities and Corresponding Plants/equipment Discussed in HAZOP Study Meeting

 

Extension Work Component

Construction Activity Group

Construction Activity

Plants/equipment material Involved

A. General Site Activities

A1. Site clearance and site formation

1.  Excavation

2.  Removing debris

1.    Backhoe

2.    Bulldozer

3.    Dump truck

A2. Access road construction

1.  Excavation

2.  Removing debris

3.  Paving road

1.    Backhoe

2.    Dump truck

A3. Electricity generation and supply

1.    Generate electricity

2.    Preparing electricity supply facilities and connecting electricity transmission wire

1.    Generator

A4.  Site personnel, plants and equipment mobilization

1.  Mobilizing personnel, equipment and plants by vehicles and crane

1.    Site vehicle

2.    Crane lorry

3.    Mobile crane

A5.  Material/Waste storage

1.    Storing/stockpiling of material/waste

2.   Material/waste delivery

1.    Truck

2.    Crane lorry

A6.  Operations related to fire

1.    Cooking by on-site personnel

2.    Welding

1.    Welding machines

2.    Catering equipment

3.    Liquid/gas fuel

A7.  Chemicals/fuel storage

1.    Chemicals/fuel storage

2.    Transporting chemicals/fuel

1.    Chemicals/fuel delivery vehicle

2.    Crane lorry

B.  Stage II Extension – Construction of Laboratory Extension

 

B1. Temporary works for temporary earth retaining structure, bulk excavation, piling and foundation work

1.    Excavation

2.    Piling works

3.    Concrete slab demolition

4.    Transporting large objects and equipment

1.    Backhoe

2.    Oscillator

3.    Pneumatic breaker

4.    Roller

5.    Air compressor

6.    Tower crane

7.    Dump truck

B2. Form work erection and rebar refixing

1.    Fixing steel

2.    Mobilization of pile of steel by crane

3.    Welding

1.    Welding machine

2.    Mobile crane

3.    Tower crane

B.  Stage II Extension – Construction of Laboratory Extension

 

B3.  Concreting

1.    Mixing concrete

2.    Pour concrete into structure

 

1.    Concrete mixer

2.    Crane lorry

3.    Tower Crane

4.    Backhoe

5.    Vibrator

B4.  Column and Roof

1.  Transferring large objects and equipment

1.  Mobile crane

B5.  Brickwork and finishing

1.    Welding

2.    Transferring large objects and equipment

1.    Backhoe

2.    Mobile crane

3.    Welding machine

B6.  E&M installation

1.    Welding

2.    Transferring large objects and equipment

1.    Mobile crane

2.    Backhoe

3.    Welding machine

B7.  Landscaping Work

1.    Excavation for soft landscape works implementation

2.    Tree plantation for soft landscape works

1.    Backhoe

2.    Crane lorry

C.  Stage II Extension- Construction of Sludge Thickener and Washwater Tank

C1. Temporary works for temporary earth retaining structure, bulk excavation, piling and foundation work

1.    Excavation

2.    Piling works

3.    Concrete slab demolition

4.    Transporting large objects and equipment

1.    Backhoe

2.    Oscillator

3.    Pneumatic breaker

4.    Roller

5.    Air compressor

6.    Tower crane

7.    Dump truck

C2. Form work erection and rebar refixing

1.    Fixing steel

2.    Mobilization of pile of steel by crane

3.    Welding

1.    Welding machine

2.    Mobile crane

3.    Tower crane

C3.  Concreting

1.    Mixing concrete

2.    Pour concrete into structure

 

1.    Concrete mixer

2.    Crane lorry

3.    Tower Crane

4.    Backhoe

5.    Vibrator

C4.  Column and Roof

1.  Transferring large objects and equipment

1.  Mobile crane

C.  Stage II Extension- Construction Sludge Thickener and Washwater Tank

C5.  Brickwork and finishing

1.    Welding

2.    Transferring large objects and equipment

1.    Backhoe

2.    Mobile crane

3.    Welding machine

C6.  E&M installation

1.    Welding

2.    Transferring large objects and equipment

1.    Mobile crane

2.    Backhoe

3.    Welding machine

C7.  Landscaping Work

1.    Excavation for soft landscape works implementation

2.    Tree plantation for soft landscape works

1.    Backhoe

2.    Crane lorry

D.  Stage II Extension – Construction of Pre-treatment Contact Chambers, Rapid Mix Chambers, Flocculation Tanks, Sedimentation Basins, Intermediate Ozone Tank and BAC Filters

D1. Temporary works for temporary earth retaining structure, bulk excavation, piling and foundation work

1.    Excavation

2.    Piling works

3.    Transporting large objects and equipment

1.    Backhoe

2.    Oscillator

3.    Pneumatic breaker

4.    Roller

5.    Air compressor

6.    Tower crane

 

D2. Form work erection and rebar refixing

1.    Fixing steel

2.    Mobilization of pile of steel by crane

3.    Welding

1.    Welding machine

2.    Mobile crane

3.    Tower crane

D3.  Concreting

1.    Mixing concrete

2.    Pour concrete into structure

 

1.    Concrete mixer

2.    Crane lorry

3.    Tower Crane

4.    Backhoe

5.    Vibrator

D4.  Column and Roof

1.  Transferring large objects and equipment

1.  Mobile crane

D5.  Brickwork and finishing

1.    Welding

2.    Transferring large objects and equipment

1.    Backhoe

2.    Mobile crane

3.    Welding machine

D6.  E&M installation

1.    Welding

2.    Transferring large objects and equipment

1.    Mobile crane

2.    Backhoe

3.    Welding machine

D.  Stage II Extension – Construction of Pre-treatment Contact Chambers, Rapid Mix Chambers, Flocculation Tanks, Sedimentation Basins, Intermediate Ozone Tank and BAC Filters

D7.  Landscaping Work

1.    Excavation for soft landscape works implementation

2.    Tree plantation for soft landscape works

1.    Backhoe

2.    Crane lorry

E.  Stage II Extension – Construction of Lime Saturators

E1.  Temporary works for temporary earth retaining structure, bulk excavation, piling and foundation work

1.    Excavation

2.    Concrete slab demolition

3.    Transporting large objects and equipment

1.    Backhoe

2.    Oscillator

3.    Pneumatic breaker

4.    Roller

5.    Air compressor

6.    Tower crane

7.    Dump truck

 

E2. Form work erection and rebar refixing

1.    Fixing steel

2.    Mobilization of pile of steel by crane

3.    Welding

1.    Welding machine

2.    Mobile crane

 

E3.  Concreting

1.    Mixing concrete

2.    Pour concrete into structure

 

1.    Concrete mixer

2.    Crane lorry

3.    Backhoe

4.    Vibrator

E4.  Brickwork and finishing

1.    Welding

2.    Transferring large objects and equipment

1.    Backhoe

2.    Mobile crane

3.    Welding machine

E5.  E&M installation

1.    Welding

2.    Transferring large objects and equipment

1.    Mobile crane

2.    Backhoe

3.    Welding machine

E6.  Landscaping Work

1.    Excavation for soft landscape works implementation

2.    Tree plantation for soft landscape works

1.    Backhoe

2.    Crane lorry

F.  Stage II Extension – Installation of one additional Filter Press

F1.  E&M installation

1.    Welding

2.    Transferring large objects and equipment

1.    Mobile crane

2.    Backhoe

3.    Welding machine

G. Stage II Extension- Construction of Ozonation Building/ Facilities

G. Stage II Extension- Construction of Ozonation Building/ Facilities

G1.  Form work erection and rebar refixing

1.    Fixing steel

2.    Mobilization of pile of steel by crane

3.    Welding

1.    Welding machine

2.    Mobile crane

3.    Tower crane

 

G2.  Concreting

1.    Mixing concrete

2.    Pour concrete into structure

 

1.    Concrete mixer

2.    Crane lorry

3.    Backhoe

4.    Vibrator

G3.  Column and roof

1.  Transferring large objects and equipment

1.  Mobile crane

G4.  Brickwork and finishing

1.    Welding

2.    Transferring large objects and equipment

1.    Backhoe

2.    Mobile crane

3.    Welding machine

G5.  E&M installation

1.    Welding

2.    Transferring large objects and equipment

1.    Mobile crane

2.    Backhoe

3.    Welding machine

G6.  Landscaping work

1.    Excavation for soft landscape works implementation

2.    Tree plantation for soft landscape works

1.    Backhoe

2.    Crane lorry

H. Stage II Extension – Construction of Pipeline Extension

H1.  Pipeline laying

1.    Excavation

2.    Transferring pipeline

3.    Connecting extended pipework

4.    Welding

1.    Backhoe

2.    Crane lorry

3.    Welding machine

I.   Stage II Extension – Testing and Commissioning of Chlorine-related Extension Installation

I1.  Testing and Commissioning

1.    Check the reliability of the equipment

2.    Purge the gaseous nitrogen through the extended pipework

3.    Inject chlorinated water into the contact tank

 

J.   Stage II Extension – Testing and Commissioning of Ozone-related Installation

J1.  Testing and Commissioning

1.    Check the reliability of the equipment

2.    Purge the gaseous nitrogen through the extended pipework

3.    Inject ozone into the contact tank

 

K.  Stage I Modification – Installation of Pumps for Siu Ho Wan Raw Water and Fresh Water Pumping Station

K1.  E&M installation

1.  Retrofitting water pump with higher capacity, including installation of additional pumps and replacement of existing pumps

1.    Crane lorry

2.    Welding machine

L.  Stage I Modification – Converting one Sedimentation Basin into an Intermediate Ozone Contact Tank

L1.  Demolition work

1.    Demolition of concrete slab of existing facilities

2.    Removing debris

1.    Pneumatic breaker

2.    Dump truck

L2.  Retrofitting works and E&M works

1.    Transferring large objects and equipment

2.    Retrofitting the ozone contact tank equipment

3.    Welding

1.    Crane lorry

2.    Backhoe

3.    Welding machine

M. Stage I Modification – Retrofitting of Lamella Settlers in the Sedimentation Basins

M1.  Demolition Work

1.    Demolition of concrete slab of existing facilities

2.    Removing debris

 

1.    Pneumatic breaker

2.    Dump truck

M2.  E&M installation

1.    Retrofitting lamella settlers

2.    Welding

 

1.    Crane lorry

2.    Tower crane

3.    Welding machine

N.  Stage I Modification – Installation of Equipment for Alum Sludge Holding Tanks Nos. 3 & 4 inside Chemical Storage Building

N1.  E&M installation

1.    Provision of equipment for alum sludge holding tanks

2.    Welding

1.    Crane lorry

2.    Welding machine

9.6              HAZOP Study

    Introduction

 

9.6.1        A HAZOP Study is the method for identifying hazards and problems which prevent efficient operation.  It is a technique whichthat  provides opportunities for people to let their imaginations go free and think of all possible ways in which hazards or operationg problem might arise.  Moreover, it is done in a systematic way in order to reduce the chance that something is missed,.  which dDuring the Study, each component of the Project (construction activity and corresponding plants/equipment in this case) and each sort of hazard is considered in turn.  The Study is conducted by a team so that the team members can stimulate each other and build upon ideas from each other.

9.1.1Water Supplies Department (WSD) commissioned consultants to conducted a Preliminary Project Feasibility Study (hereinafter referred to PPFS) in respect of the project “Siu Ho Wan Water Treatment Works Extension” (hereinafter referred to as the Project) in January 1999.  The PPFS summarized the requirements of the Project and described the studies undertaken and the new works required, together with the outline designs for principal elements of the Project, cost estimate, land requirements and implementation programme.

The Assignment

9.1.1Following the PPFS, Metcalf & Eddy Ltd. has been commissioned by WSD to carry out the Extension of Siu Ho Wan Water Treatment Works Investigation (the Project) under Agreement No. CE 75/2002 (WS) (the Assignment).

9.1.1  

The objective of this Assignment is to investigate into the feasibility of the proposed extension of SHW WTW.  The Assignment is as follows:

 

·To produce the optimum preliminary design and to define the outline of the works to enable detailed design to proceed;

·To identify all technical requirements/constraints including operational land, environmental impact, hydraulic, surge and geotechnical, etc. and to establish the acceptability and practicability of the works;

·To identify the site conditions and factors that have to be considered in the detailed design;

·To carry out an Environmental Impact Assessment (EIA) study and to obtain Environmental Permit for the Project; and

·To prepare contract strategy, programme and cost estimates for the works.

 

9.1.1The commencement date of the Assignment is 10 June 2003 and the study period is scheduled to be 18 months.

 

The locations of the Project Works are shown in Figures 1.1a and 1.1b.  The layout plan of SHW WTW Extension is illustrated in Figure 1.2.    The Project will comprise the following:

 

(a)                        Extension of the Siu Ho Wan Water Treatment Works from the capacity of 150,000 m3/day to 300,000 m3/day together with the associated uprating of the capacity of the Siu Ho Wan Raw Water and Fresh Water Pumping Stations;

(b)                        Construction of the proposed Siu Ho Wan Raw Booster Pumping Station and laying of the associated water mains;

(c)Demolition and reprovision of the existing Pui O Pumping Station;

(c)Uprate of capacity of the Pui O No. 2 Raw Water Pumping Station; and

(c)Duplication of two sections, approximately 2km, of 1200mm diameter water mains at Pui O.

 

9.1.1In accordance with the Project Study Brief, an initial assessment of the environmental impacts arising from the Project is required to identify those environmental issues of key concern during the construction and operation phases of the Project that require more detailed assessment.  The findings of the initial assessment are presented in this Initial Assessment Report (IAR).    

 

9.1Objectives of EIA Study

9.1.1The Project is a designated project under Schedule 2, Part I(E2) of the Environmental Impact Assessment Ordinance (EIAO) (Cap. 499) and requires an environmental permit under the EIAO for the implementation of the Project.  The Project Profile (No. PP-073/2000) for the Project was submitted to EPD on 17 January 2000.  The EIA Study Brief (No. ESB-046/2000) for an Environmental Impact Assessment (EIA) study brief under section 5(7)(a) of the EIAO was issued by the EPD on 15 February 2000. 

 

9.1.1The purposemain objective of the 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.  The information will contribute to decisions on:

 

·overall acceptability of any adverse environmental consequences that are likely to arise as a result of the proposed Project;

·the conditions and requirements for the detailed design, construction and operation of the proposed Project to mitigate against adverse environmental consequences wherever practicable; and

·the acceptability of residual impacts after the proposed mitigation measures are implemented.

 

the acceptability of residual impacts after the proposed mitigation measures are implemented.

 

9.1Objectives of EIA Study

9.1.1This IAR will provide an initial assessment of the potential environmental impacts in relation to the following likely key issues associated with the Project. e objectives of the EIA Study are as follows:

 

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

 

(a)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;

 

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

 

(a)to identify and quantify any potential losses or damage to flora, fauna and natural habitats;

 

(a)to identify any negative impacts on sites of cultural heritage and to propose measures to mitigate these impacts;

 

(a)to identify any potential landscape and visual impacts and to propose measures to mitigate these impacts;

 

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

 

(a)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;

 

(a)to identify, assesses 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;

 

(a)to investigate the extent of side-effects of proposed mitigation measures that may lead to other forms of impacts;

 

(a)to identify constraints associated with the mitigation measures recommended in the EIA study; and

 

to design and specify the environmental monitoring and audit requirements, if required, to ensure the implementation and the effectiveness of the environmental protection and pollution and pollution control measures adopted.

9.1Assessment Area

9.1.1The Assessment Area for the purpose of the EIA Study, as specified in the BriefEIA Study Brief, is presented below:

·Air quality assessment – the assessment area shall be a distance of 500m from the Project boundary.

·Noise impact assessment – include all areas within 300 m from the Project boundary.  If the first layer of noise sensitive receivers provides acoustic shielding to those receivers further from the site, the assessment area could be reduced accordingly, subject to the agreement of DEP.

·Water quality impact assessment - the assessment area for the water quality impact assessment is defined by a distance of 500m from the Project site boundary.  include all areas within 500 m from the Project boundary.  The area shall include but not limited to Pui O freshwater stream.

·Ecological impact assessment - the assessment area for terrestrial ecological assessment shall include all areas within 500 m distance from the site boundary of the works areas, or the area likely to be impacted by the Project.  For aquatic ecology, the assessment area shall be the same as for water quality assessment.

·Landscape and visual impacts - the assessment area for landscape impact assessment shall include all areas within a 500 m distance from the work limit of the proposed Project, while the assessment area for the visual impact assessment shall be defined by the visual envelope of the Project.

·Cultural heritage impact study - all sites of cultural heritage that might be adversely affected by the impacts due to construction activities of the Project.

·Hazard assessment – consultation zone for hazard assessment of the Potentially Hazardous Installation at SHW WTW as shown in Figure 9.1.

 

9.1Organisation of the Report

9.1.1The remainder of the report is organised as follows:

 

i)understanding of EIA Study objectives and key environmental issues;

i)proposed approach and methodology;

i)programme for the EIA Study; and

·environmental study teamSection 2 - Project Description & Option Evaluation

·Section 3 – Air Quality Impact

·Section 4 – Noise Impact

·Section 5 – Water Quality Impact

·Section 6 - Ecological Impact

·Section 7 – Landscape and Visual Impact

·Section 8 - Cultural Heritage Impact

·Section 9 - Hazard to Life

·Section 10 - Waste Management Implications

·Section 11 - Environmental Monitoring & Audit

·Section 12 – Overall Conclusions

 

CVs of key study team members are presented in Appendix A.

UNDERSTANDING of OBJECTIVES & key issuesproject description

Understanding of ObjectivesIntroduction

The site for the proposed Siu Ho Wan Treatment Works extension is within the boundary of the existing Siu Ho Wan Treatment Works.  The location of the site is about 100m south of the North Lantau Highway which is bounded by a Sewage Treatment Plant in the southwest and North Lantau Service Road in the north.  The proposed location is illustrated in Figure 2.1a

The site for the proposed raw water booster pumping station is located immediately next to the entrance of Siu Ho Wan shown in Figure 2.1a.  The proposed site will have an area of approximately 0.5 hectares and the pumping statin will be about 8m in height.  One of the alternative sites is proposed to located 800m South from Ta Pang Po

 The proposed site of the Project is located on the The locations of the Project Works are shown in Figures 1.1a and 1.1b.  The layout plan of SHW WTW Extension is illustrated in Figure 1.2.    The Project comprises the following:

 

(a)                        Extension of the Siu Ho Wan Water Treatment Works from the capacity of 150,000 m3/day to 300,000 m3/day together with the associated uprating of the fresh water pumping capacity of the Siu Ho Wan Raw Water and Fresh Water Pumping Station;

(b)                        Construction of the proposed Siu Ho Wan Raw Water Booster Pumping Station and laying of the associated water mains;

Demolition and reprovision of the existing Pui O Raw Water Pumping Station;

Uprate of capacity of the Pui O No. 2 Raw Water Pumping Station; and

Duplication of two sections, approximately 2km, of 1200mm diameter water mains at Pui O.

The SHW WTW extension Project is a Designated Project under Schedule 2, Part I(E) of the EIA Ordinance.  One of the main objectives of the Assignment is to undertake an EIA Study to fulfil the statutory requirements of the Ordinance, and to assist WSD to obtain the Environmental Permit for this Project. 

Key IssuesProject Programme

Figures 2.1, 2.2 and 2.3 illustrate the key environmental issues in relation to the Project.

Noise ImpactConstruction and Operational Activities

Construction noise generated from powered mechanical equipment(PME) for activities such as site clearance, earthworks and concreting would be an issue given the proximity of noise sensitive receivers (NSR) in close vicinity to the works at Pui O such as village houses of Lo Uk Tsuen, Pui O San Wan, Pui O Lo Wan, BPui O Public School and Pui O Rural Committee Office. 

The potential operational noise sources would be arising from the pumps of the proposed pumping stations.  Houses at the Pui O Lo Wan close to the Pui O pumping stations would require control of operational noise.

Ecological ImpactsNeed of the Project

The Project Profile indicated that woodland/shrubland habitat loss of about 8000 m2 for alternative alignment and 1600 m2 for the option of laying most of the pipeline under the existing road at Pui O.

In addition, the key ecological resources that may be impacted included the followings:

Woodland habitat of Lantau South Country Park – cut across by a short section of the alternative alignment near the northern end

Pui O wetlands – directly impacted by alternative alignment

Natural streams and Pui O mangrove stand

 

Cultural HeritageConsideration of Alternative Options

The Pui O No. 2 Raw Water Pumping Station and associated water mains falls within the known Pui O Archaeological Site. Findings to date indicate that the site was occupied or used during the historic period.  Burials belonging to the Six (A.D. 220-589) and Qing Dynasties (A.D. 1644-1911) have been excavated at Pui O. These findings are relatively unique in the Territory.   Kiln structures and related features dated to the Tang Dynasty (A.D. 618-907) have also been recorded.  Although the site has not yielded prehistoric findings, its landform and location suggests such deposits may be present. 

 

Works at Pui O are in proximity to historical buildings and other features associated with the villages of Pui O Lo Wai Tsuen and Pui O San Wai Tsuen. 

Landscape & Visual

Given that the proposed WTW extension and Raw Water Booster Pumping Station would be in a developed area of the Siu Ho Wan area with an established “industrial” character, potential landscape and visual impacts would be low.  The proposed booster pumping station may create visual and landscape impact along the North Lantau Highway (NLH) which is the gateway corridor of Hong Kong.  The key pPotential impacts of the Project would also be expected mainly in the Pui O area.  Construction of the Pui O Raw Water Pumping Station and main laying would have visual impact, given the proximity to visually sensitive receivers particularly residents next to the existing pumping station or any nearby historical buildings.  Main landscape impact would be loss of vegetated areas particularly woodlands (e.g. in the Lantau South CP). 

Water Quality

Potential sources of impact on water quality during the construction works would include:

Construction runoff and drainage.

General construction activities e.g. debris, refuse and liquid spillage of any fuels stored on-site.

Sewage effluents from the construction workforce.

Disturbance to or loss of aquatic systems.

 

Impacts on Water Sensitive Receivers such as Siu Ho Wan, Pui O Beach, stream courses and mangroves would require proper site management practices.  The water pollution control measures would be required to prevent the construction works affecting the treatment process at the SHW WTW.

Waste Management

Good management and disposal of excavated material and construction waste will be required.  Sludge and wastewater would be the main operational waste and should be strictly managed and disposedal of.

Construction activities of the Project may initiate additional risk of chlorine accidents during transport, handling and storage of chlorine in the existing WTW.

In the operational phase of the Project, if there is an increase of storage and on-site transport of chlorine, the associated risk would be higher than that evaluated previously in the Hazard Assessment Study conducted in 1992 and its compliance with the Risk Guidelines would need to be evaluated.   

 

 

Air Quality

Potential dust impacts may be arising from Cc on the nearby air sensitive receivers, especially the Pui O village houses.  The implementation of the dust suppression measures would be required.   may initiate additional risk of chlorine accidents during transport, handling and storage of chlorine in the existing WTW.

 

APPROACH AND METHODOLOGYAir Quality

Introduction

The technical approach to undertake the EIA Study for the environmental issues outlined in Section 2 is presented below. All impact assessments will be carried out in accordance with the requirements of the EIAO Technical Memorandum (TM) and the EIA Study Brief. The EIA Study will take into account of the potential cumulative impacts with any major concurrent projects in the vicinity.

Inception StageEnvironmental Legislation and Standards

Task 1: Study Initiation, Data Collection and Review

The latest relevant background information and reports on the study area from AMO, EPD, DSD, AFCD and PlanD, will be obtained.  The data and study reports will be collated and to provide an updated baseline profile of existing conditions.

Baseline StageBaseline Conditions

Task 2: Baseline Review

The review of relevant reports and studies will be continued to establish in detail the baseline environmental profile of the assessment area.  Field visits will be undertaken to confirm and update the nature of the study area and surroundings, and the baseline data and sensitive receivers.

 

Task 3: Field Survey and Investigation

Field surveys or investigations will be initiated to fill in the data gaps identified in the baseline review and to complete the environmental baseline profile of the assessment area. 

 

Task 4: Alternatives Options Input

Based on the literature review and interim data available from the project specific field surveys and investigations, an initial review of potential environmental impacts of alternative options will be undertaken and input provided to the evaluation of alternative siting or alignment options. 

Detailed Assessment StageAir Sensitive Receivers

Detailed assessment of environmental issues will be undertaken based on the preferred siting, design and alignment option.

Assessment Methodology & Criteria

 

Task 5: Ecological Impact

A review of the ecological data will be undertaken including HKU Biodiversity Survey and Hong Kong Breeding Bird Survey and recent surveys on Pui O area from relevant studies.

More specific ecological surveys will be undertaken to fill in the identified data gaps and update the previous data, in liaison with AFCD.

 

Ecological Surveys

The field surveys will focus on the proposed works areas, and be undertaken for a duration of at least 3 months, covering the wet season. The surveys will cover habitats, vegetation, birds, mammals, aquatic communities, herpetofauna and invertebrates (butterfly & dragonfly).

The surveys will focus on the work areas, and also covering the area 500m from the works area.

 

Impact Assessment

A habitat map will be produced, showing sites of conservation importance, as well as distribution and abundance of any rare or protected species within the assessment area. The establishment of baseline ecological conditions and impact assessment will follow the EIAO TM requirements and criteria (Annexes 8 and 16), evaluating both on‑site and off‑site impacts quantitatively where possible.   Ecological impacts to be addressed include the direct, indirect and cumulative impacts of habitat loss, and disturbance associated with construction and operation of the Project, with particular attention to the impact on conservation areas.  Practical mitigation measures will be recommended, to avoid, minimize, and/or compensate for the adverse ecological impacts identified and ensure there is no unacceptable impact.

 

Task 6: Cultural Heritage

A desk-based study will be undertaken to compile all available information regarding the cultural heritage potential within close proximity to the study corridor. 

If the desk-based study identifies any additional areas of archaeological potential within the Study Area the Antiquities and Monuments Office may require a field investigation to be carried out to verify this potential.Historical buildings and structures as well as other resources, which fall within the AMO definition as presented in the Criteria for Cultural Heritage Impact Assessment will be recorded through a comprehensive field survey. The scope of the survey has been defined in the brief. All identified cultural heritage features will be recorded using standardised recording forms.The historical value of and potential impacts on the identified structures and any identified archaeological deposits will be evaluated following accepted standards and procedures. Measures will be recommended to mitigate the impacts of the proposed works. 

 

 

 

 The findings of the desk-based study, the built heritage and archaeology survey, if required, and the assessment and mitigation recommendations; including plans, master layout plan and cross-referenced check-list would be presented in the report.

 

                                                Task 7: Landscape and Visual Impact

The methodology will follow the Brief requirements, section 1 of Annex 10 and Annex 18 of the Technical Memorandum of the EIA Ordinance (EIAO-TM) and related Explanatory Notes.

A baseline desktop study of relevant plans and studies, and site inspection of the area will produce and map an inventory of the key landscape and visual features of the assessment area.   The baseline study will also identify the representative viewpoints or visually sensitive receivers.  

The impact assessment will examine the construction and operational impact of the Project on the existing landscape and identified visually sensitive receivers within the visual envelope.  The landscape impact will be quantified in terms of the approximate area loss of main landscape features such as woodland area. The level and significance of the landscape and visual impact will be based on an established system with criteria such as number of receivers and duration of impact.

Mitigation measures will be proposed to minimise potential impacts and the proposed mitigation measures will be illustrated graphically, such as by photomontages. 

 

                                                Task 8: Water Quality Impact

The water system(s) and sensitive receivers which may be affected during the construction and operation stages of the Project will be identified and confirmed through a site visit.  All the identified sources of potential water quality impact will be evaluated and their impact significance determined, such as impacts due to construction runoff and drainage, sediment resuspension from excavation works and downstream siltation impacts, and water pollution due to site construction activities.

Requirements for mitigation measures to minimize any identified adverse impacts on the water system(s) and sensitive receivers will be recommended.  The use of containment structures and diversion channels is recommended wherever practicable to facilitate a dry or at least confined excavation within watercourses.  By limiting or confining the works areas the extent of disturbance to the surrounding wetland habitats will be significantly reduced, and thus resulting impacts on water quality from sediment resuspension will be reduced.

 

Task 9: Noise Impact

Potential noise impacts will be assessed in accordance with the criteria and methodology given in the TM made under the Noise Control Ordinance, EIAO, and also the Hong Kong Planning Standards and Guidelines. Construction works associated with this Project would elevate ambient noise levels in areas immediately adjacent to excavation zones and along the access route used to transport construction materials and equipment and to export excavated spoil material. Construction noise impact will be assessed. Sound power levels from the potential construction equipment plants will be established and the noise impacts on the identified noise sensitive receivers (NSRs) will be calculated.  Appropriate noise mitigation measures such as quietened equipment, noise barriers, will be recommended. During operation phase, noise from proposed plant and equipment such as pumps, will be controlled, where necessary, by careful location of plant, or acoustic shielding/cover.

 

Task 10: Waste Management

Waste generation sources (e.g. excavated land-based materials, general construction wastes, chemical wastes and sludge from WTW) will be identified, quantified and characterized. Appropriate waste handling, on-site storage (chemical wastes & sludge), transportation and disposal routes for each type of waste will be recommended. The assessment and recommendation will be undertaken with reference to the requirements in Waste Control Ordinance, its subsequent legislation and regulations.

 

Task 11: Construction Air Quality Impact

An emission inventory will be developed and construction dust impact of the proposed engineering works on Air Sensitive Receivers (ASR) will be assessed.  

 

Task 12: Hazard to Life

A Hazard and Operability (HAZOP) study will be conducted to identify additional hazards initiated by construction activities.  The HAZOP study will cover the possible failure events, human errors and external hazards initiated by the construction activities (e.g. excavation) which may increase the risk of chlorine accidents during storage, handling and transport of chlorine.  Risk mitigation measures to be implemented during construction phase will be proposed where necessary.

A quantitative risk assessment (QRA) Study will be conducted if (and only if) there is an increase of storage and on-site transport of chlorine in the operational phase of the Project. Relevant information such as data on engineering designs and operational practices, information of subject site area, existing / future population data, meteorological data and other necessary data will collected at the initial stage of the QRA Study.  Potential hazards and estimating associated frequencies by reviewing design of the water treatment works system and by making reference to relevant local and international studies will be identified.

 

Task 13: Preparation of ReportsIdentification of Environmental Impacts

Construction Phase

The findings, conclusions and recommendations of the detailed assessment will be assimilated and presented in a Final EIA Report (including an Executive Summary and EM&A Manual) for submission to EPD under the EIAO for formal approval.  The recommended mitigation measures and EM&A requirements for the construction and operational phases of the Project will be presented in the Final EIA Report, together with the Implementation Schedule.

 

Operational Phase

 

 

Initial Evaluation of Impacts

Construction Phase

 

Operational Phase

Mitigation Measures

Further Studies

In order to assess and evaluate the air quality impact arising from the proposed Project, detail assessment will be carried out in the subsequent Draft Environmental Impact Assessment Stage.

Conclusion

 

STUDY programme

Works Programme

A preliminary study programme for the Assignment is presented in Figure 4.1.  This illustrates the sequence of the various tasks to be undertaken over the duration of the EIA Study as detailed in Section 3.

Deliverable and Meeting Schedule

A tentative schedule of the deliverable submission dates is presented in Table 4.1.

 

Table 4.1                        Key Deliverables Submission

 

Deliverable

Date

(Study Commencement)

10 June 2003

Draft EIA Inception Report

9 July 2003

Final EIA Inception Report

9 August 2003

Draft EIA Initial Assessment Report

9 October 2003

EIA Initial Assessment Report

9 November 2003

Draft EIA Report & Executive Summary

9 February 2004

Draft EM&A Manual

9 February 2004

Final EIA Report & Executive Summary

9 April 2004

Final EM&A Manual

9 April 2004

Team Members

 

 

9.1.1The HAZOP Study Team members consisted of 16 members:

 

Anna Chung  Team leader, MEMCL

C.F. Lai    Engineer (Project Management), WSD

W.K. Yeung  Chemist, WSD

L.H. Li     Senior Chemist, WSD

P.W. Lee     Engineer, WSD

K.K. Wong    Mechanical Engineer (Maintenance), WSD

W.K. Lui    Mechanical Engineer (Project), WSD

K.Y. Tse    Electrical Engineer (Project), WSD

F.C. Cheung  Electrical Engineer (Maintenance), WSD

L.M. Chan     Engineer (Design), WSD

K.S. Kong    Senior Engineer (Safety), WSD

K.C. Cheung  Assistant Inspector, WSD

C.W. Lee    Senior Inspector, WSD

Angela Wong  Project Engineer, M&E

Arthur Lee    Safety Representative, MEMCL

Wilson Kwok  Environmental Representative, MEMCL

 

            Methodology

 

9.6.2        The basic concept of this HAZOP Study, is to take full description of the expected construction activities by a summary table (as shown in Table 9.1) and an extension layout plan (as shown in Figure 9.1), then to question every construction activity and its corresponding plants/equipment to discover what deviation[1] from the intention[2] of the activities can occur and what their causes[3] and consequences[4] would be.  This is executed systematically by applying suitable guidewords, which can assist prompt thinking about what might go wrong.

 

9.6.3        In the Study Meeting, all construction activities (and corresponding plants/equipment) arewere discussed in turn with the procedures explainedlisted as follows:

 

1.      Explain the intention of the construction activity (and corresponding plants/equipment) to be discussed

2.      Identify possible deviations of the construction activity (and corresponding plants/equipment) being discussed.  The possible deviations were detected by systematic application of guidewords

3.      Spot possible causes of the identified deviations

4.      Evaluate the possible consequences due to the deviation identified

5.      Recommend possible mitigation measures to avoid the occurrence of the deviations

6.      Identify the responsible parties to implement the recommended mitigation measures

7.      Record the findings and recommendation during the discussion

 

HAZOP Study Execution

 

9.6.4        One session of the Study Meeting was conducted.  The Study Meeting was conducted in the following sequence:

 

1.      Clarified the scope and objectives of this HAZOP Study, which were stated in the EIA Study Brief to the Study Team

2.      Explained the definition of ‘hazard’ to be identified, methodology and procedure of the HAZOP Study to the Study Team

3.      Presented each process of the proposed extension works of Siu Ho Wan WTW to the Study Team

4.      Finalized the possible construction activities (and corresponding plants/equipment) to be discussed in the Study

5.      Discussed each possible construction activity in turn with procedure listed in Section 9.4.3.

6.      The Study Meeting ended after all possible construction activity were discussed

 

9.7              Findings and Recommendations

9.7.1        As mentioned in Section 9.4.4, the followings were identified or recommended during the HAZOP Study:

 

·      Causes of possible deviations

·      Hazardous scenarios which could lead to chlorine leakage/release (i.e. consequence)

·      Mitigation measures to avoid occurrence of deviations and corresponding responsible parties

 

9.7.2        The aim of the HAZOP Study is to identify additional chlorine hazards during construction additional hazards and mitigate them as far as possible.  It is considered that each of the identified hazardous scenarios could cause personnel injury or fatality including WSD staff and construction workers on site.  In order to mitigate the possible hazards identified, all the mitigation measures identified by the HAZOP team and suggested by FSD are to be incorporated in the construction contract to ensure their implementation.

 

9.7.3        As suggested by EPD, a summary description of interface between construction activity and the Chlorine Building is given in Table 9.2.  It should be noted that most of the activities presented in the Table below could cause hazard to the Chlorine Building if they are operated at an inappropriate location (i.e. too close to the Chlorine Building).  Ensuring the activities to be implemented at appropriate location would be an effective mitigation measures.

 

Table 9.2    Interface between Construction Activities and the Chlorine Building

 

Construction Activity/ Plant

Interface

Excavation near Chlorine Building

Too much excavation may needlead to structural damage of Chlorine Building

Piling Works

Too much vibration may lead to structural damage of Chlorine Building

Demolition of concrete slab of existing facilities by pneumatic breaker

Inappropriate method of demolition may cause damage to chlorine dosing pipework, which causes chlorine leakage.

Backhoe

Bulldozer

Dump truck

Site Vehicle

Crane lorry

Mobile crane

Roller

Tower Crane

Construction plant/equipmentBackhoe crashes into Chlorine Building/ overturn; may cause structural damage

Preparing electricity supply facilities and connecting electricity transmission wire in Chlorine Building

Accidents initiated by electricity supply facilities installed inside/adjacent to Chlorine Building could cause damage to the chlorine-related installation

Generator, air compressor

Fire/explosion of generator may cause structural damage to the Chlorine Building

Mobilizing personnel

Construction workers enter Chlorine Building without supervision; may cause damage to chlorine-related facilities

Mobilizing construction equipment/ plant

Construction equipment/ plant being mobilized causes impact on Chlorine Building; may cause structural damage to Chlorine Building

Storing/stockpiling of material/waste near Chlorine Building

Fire accidents involving stored flammable waste near Chlorine Building impose fire hazard to Chlorine Building

Cooking by on-site personnel near Chlorine Building

Accidents involving fuels used in cooking causes fire hazard to Chlorine Building

Welding near Chlorine Building

Accidents involving fuels used in welding and sparks produced during the operation cause fire hazard to Chlorine Building

Chemicals/fuel storage near Chlorine Building

Fire of chemicals/fuel stored may impose fire hazard to the Chlorine Building

Transferring pile of steel/ large objects and equipment

Inappropriate transferring operation could cause material/object/equipment being transferred or equipment involved cause impact on Chlorine Building; may cause structural damage

Tree plantation for soft landscape works

Roots of planted trees (with unknown extent of roots) near Chlorine Building may cause structural damage   damage

 

 

 

9.7.4        The above items identified during the HAZOP Study were summarized into different categories in Tables 9.32 – 9.45 as shown below.  Appendix 9.1 summarized the mitigation measures to be incorporated in the construction contract.

 

 

 

 

 

 

 

 

 

 

Table 9.32    Summary of Identified Possible Deviation Causes

 

Category

Identified Possible Deviation Causes

Lack of monitoring and investigation

·      Lack of monitoring of the construction activities

·      Lack of investigation on the consequence of construction activities to chlorine-related facilities

Poor chemicals/waste/material management and storage

·      Accumulation of stacked debris

·      Too much material stockpiled

·      Too much chemicals/fuel stored

·      Chemicals/waste/material stored at inappropriate locations

·      Fire accidents involving flammable waste/fuels/chemicals

Poor maintenance or installation of plant/equipment

·      Poor maintenance of equipment

·      Damage of equipment undetected

·      Malfunction of brake of vehicles

·      Insecure plant/equipment installation (e.g. counter weight of tower crane)

Inappropriate location of construction activity

·      Construction activity on travelling route of Chlorine Delivery Truck

·      Construction activity too close to Chlorine Building

·      Construction activity too close to Cchlorine-related facilities

·      Excavation takes place at locations which underground chlorine pipeworks are installed

Inappropriate equipment operation

·      Operator unable to properly manipulate the equipment

·      Equipment overloaded

·      Speed of vehicle is too high

Conflict to chlorine delivery operation

·      Equipment/vehicle is idle or working near/along the Chlorine Delivery Truck traveling route

·      The chlorine delivery operation and chemicals/fuel delivery operation are conducted on site simultaneously

Miscellaneous

·      Too high vibration intensity caused by piling works

·      Construction workers are not aware about the locations accommodating chlorine-related facilities 

·      Plantation of trees with unknown extent of roots

·      Extended chlorine pipework connectiong work commences before chlorine is isolated in existing facilities

 

Table 9.43        Summary of Hazardous Scenarios could leading to Chlorine Leakage/release

 

Identified Hazardous Scenarios

·          Structural damage to Chlorine Building

·          Damage to chlorine dosing facilities

·          Damage to Chlorine pipeworks

·          Obstruct Chlorine Delivery Truck access route; could cause accident of the vehicle

·          Cause Chlorine Delivery Truck unsuitable for driving; could cause accident of the vehicle

·          Vehicle/equipment crashes to Chlorine Delivery Truck, or vice versa

·          Fire hazard to chlorine related-facilities

 

 

 

 

 

 

 

 

Table 9.54                 Summary of Mitigation Measures to Avoid Occurrence of Deviations and Corresponding Responsible Parties

 

Category

Mitigation Measures Identified

Parties Responsible

Monitoring and Inspection

·      Monitor the excavation activity to avoid excavation to the wrong depth (too much excavation)

·      Conduct monitoring to ensure the stability of building during construction phase

·      Inspection and supervision to ensure operation of equipment properly

·      Inspection of excavation progress near Chlorine Building and Chemical Storage Building

·      Contractor

 

·      Contractor

 

·      Safety Officer (Contractor)/ Contractor

·      Safety Officer (Contractor)/ Contractor

Management

Waste Management

·      Ensure good C&D waste management

·      Provide on-site sorting of debris to avoid excessive debris accumulation

·      Provide temporary storage for debris at appropriate location

·      Ensure flammable waste is stored at appropriate/designated location

 

Traffic Management

·      Maintain access roads as a freeway

·      Provide sufficient maintenance of the vehicle/generator/equipment

·      Set a speed limit for site vehicle

·      Propose a designated route for site vehicles, avoid site vehicle using travelling route of the Chlorine Delivery Truck

·      Provide adequate fire fighting equipment at the storage area

·      Provide clear road signs for site vehicles

·      Install hump on the access roads to reduce the speed of site vehicles

·      Provide crash barrier to protect the cChlorine Bbuilding and the Cchemical sStorage Bbuilding

·      No parking on access road, or proper parking area designated for dump trucks

 

Chemicals/material Management

·      Ensure good management of material delivery to avoid excessive material stock on site

·      Avoid incompatible chemicals storing together; provide separate storage locations for different chemicals which are incompatible to each other

·      Provide appropriate labels according to Dangerous Goods Ordinance

 

·      Follow Fire Services Department’s requirement for flammable waste storage

·      Keep the amount of flammable waste stored in a minimum level

·      Ensure adequate separation distance between each flammable material storage areas

·      No stockpile of material near the Chlorine Building and the access road is allowed

 

Construction Activity/personnel Management

Personnel

·      Ensure sufficient guarding at Siu Ho Wan WTW to provide sufficient access control

·      Provide clear indication of rooms accommodating chlorine-related facilities and their hazards 

 

 

 

 

 

 

Activity

·      Propose a communication system between operator of Siu Ho Wan WTW and the Contractor on the date of chlorine delivery to the WTW

·      Prepare a safetyty plan to avoid any electricity supply facilities located inside/adjacent to the Chlorine Building

·    Propose a “Permit-to-move” system for large equipment/plant movement:

·    Contractor provides WSD a list indicating the number and type of equipment/plant to be mobilized, equipment/plant movement route and mobilization methodology

·    A risk assessment is conducted by Safety Officer (Contractor)

·    No equipment/plant movement should be allowed before approval from WSD/Safety Officer is obtained

·    The “Permit” shall restrict the time period that equipment/plant can be mobilized

·    Supervision of permitted work by Safety Representatives from Contractor

·      Follow WSD’s “Permit-to-work” System for extended chlorine pipework connection

·     No connection work can commence before approval from WSD is obtained

·     Supervision of permitted works by the Contractor’s Safety Representative

·      No blasting operation on site is allowed

·      Define restricted zone for the equipment (i.e. keep the equipment from the Chlorine Building at a safety distance).  The extent of the restricted zone would be determined by the size of the equipment

·      Restrict excavation along travelling route of the Chlorine Delivery Truck

·      Limit the reach of the tower crane used

·      Ensure generators are placed at a safe distance from Chlorine Building

·      Provide indication/sign for chlorine pipeworks

·      Provide method statement with protective measures for the chlorine dosing pipeworks (and other facilities)

·      Avoid welding operation inside buildings installed with chlorine pipeworks

·      If welding is unavoidable, “Hot-work permit” system should be applied for welding operation inside buildings installed with chlorine pipeworks:

·     No welding work is allowed before approval from WSD is obtained

·     Provide supervision to the operations inside buildings installed with chlorine pipeworks by the Safety Representative from Contractor

 

Landscaping Work Management

·      Avoid plantation of deep root trees near buildings, especially Chlorine Building

 

·      Contractor

·      Contractor

 

·      Contractor

·      Contractor

 

 

 

·      Contractor

·      Contractor

 

·      Contractor

·      Contractor

 

·      Contractor

·      Contractor

·      Contractor

 

·      Contractor

 

·      WSD/ Contractor

 

 

 

·      Contractor

 

·      Contractor

 

 

·      Contractor

 

 

·      Contractor

 

·      Contractor

 

·      Contractor

 

·      Contractor

 

 

 

 

·      WSD/ Contractor

 

·      WSD/ Contractor

 

 

 

 

 

 

 

·      WSD/ Contractor

 

 

·      Contractor

 

·      WSD/ Safety Officer (Contractor)/ Contractor

 

 

 

 

 

 

 

 

 

 

 

 

·      WSD/ Safety Representative (Contractor)/ Contractor

 

 

 

·      Contractor

·      Contractor

 

 

 

·      Contractor

 

·      Contractor

·      Contractor

 

·      Contractor

·      Contractor

 

·      Contractor

 

·      WSD/ Safety Representative (Contractor)/ Contractor

 

 

 

 

 

 

 

 

·      Contractor

 

Investigation

·      Investigate the lateral support of buildings/excavation to ensure proposed extent of excavation would not affect building stability

·      Locate chlorine pipeworks before execute excavation

·      Engineer/ Contractor

 

 

·      Contractor

Training

Training

·      Provide adequate training to equipment operator; implement a license system that only competent persons could operate the equipment

·      Provide adequate training to construction workers on the rooms accommodating chlorine-related facilities and their associated hazards

·      Provide adequate training to construction workers on the nature and hazards of chlorine, safety precautions and emergency measures for leakage of chlorine from drums, piping or installations.

·      Contractor

 

 

·      Contractor

 

 

·      Contractor

 

 

Other Recommendations

 

9.7.5        The Study Team identified a number of measures during the meeting, which are not directly associated with additional chlorine hazard discussed above.  However, they are considered as appropriate measures to be implemented during the construction stage.  These measures are presented as follows:

 

i) To maintain all access roads of fire engine/FSD vehicles/ambulance as a freeway because Fire Services/Rescue personnel may approach the location of chlorine leakage from different directions, which depends on the wind direction.  No equipment/plants and site vehicle is allowed to park on the access roads.  The Contractor should take the responsibility to implement this mitigation measure. 

 

ii) Some emissions could initiate chlorine leak/smoke detector alarm (i.e. cause false alarm), which severely affects the operation of the Water Treatment Works, those emissions are listed as follows:

·         Dust from site clearance and excavation work

·         Smoke from welding work

·         Fuel vapour from electricity generation

·         Exhaust gas from construction equipment and vehicles

·         Chemicals such as bitumen, paints, organic solvent etc. 

 

 

 

Contractor should implement mitigation measures to avoid occurrence of false alarm by the following mitigation measures:

·         Provide dust suppression measures such as covering the dusty material

·         Implement “Hot-work Permit” system and provide sufficient ventilation during welding operation to avoid accumulation of smoke

·         Place the generators away from the chlorine leak/smoke detector alarms

·         Park the construction equipment and vehicles away from the Chlorine Building

·         Notify WSD prior to the use of chemical compounds and provide sufficient ventilation during operation involving chemicals

 

iii) An emergency plan should be proposed to ensure appropriate and quick response of site staff to evacuate safely in case of chlorine leakage events, the emergency plan shallould include the following items/objectives:

·           Provide a system for logging in-out record of all site staff, which could assist immediate investigation and rescue in a chlorine leak incident when required

·           Ensure construction workers be familiar with chlorine alarm system (e.g. proper training)

·           Propose construction workers to participate regular joint chlorine leak drill with arranged by WSD, and inform local fire stations in advance.

·         Propose alternative assembly point(s) for construction workers in case of chlorine leakage event

 

The measures above shallould be included in the Safety Plan and emergency plan for the extension of Siu Ho Wan WTWconstruction project.  It would be the responsibility of the Contractor for the safety plan and emergency plan preparation. Copies of the safety and emergency plans shouldshall be provided to local fire stations for information.  During the construction stage, the Contractor and staff of SHW WTW shouldshall brief local fire stations for the implementation of safety and emergency plans. 

 

9.7.6        Further to this draft EIA report, aA number of recommendations were suggested by FSD, which are not directly associated with additional chlorine hazard but which are also also of same importanceconsidered appropriate to be implemented during the construction stage.  These measures are presented as follows:

 

i)                    For the storage, conveyance and use of Ppotassium permanganate, Nnitrogen and other substances giving inflammable vapour during the construction stage, the Contractor should follow the requirements stipulated in Dangerous Goods Ordinance and its subsidiary regulations

ii)                  For the storage and conveyance of chemical waste, the Contractor should follow EPD’s requirement

iii)                 Any vegetation near the cChlorine bBuilding or work site should be trimmed to prevent the spread of fire

iv)                Sufficient number of fire extinguishers should be provided .

9.1Conclusions

9.1.1A HAZOP Study was conducted to identify additional chlorine hazards initiated by constructions activities and recommend corresponding mitigation measures for implementation in construction stage.  The Study was conducted by a Study Team consisted of representatives from WSD, M&E and MEMCL. 

 

9.1.1During the HAZOP Study, all possible construction activity and corresponding plants/equipment were discussed in turn.  Causes of possible deviations, hazardous scenarios and corresponding mitigation measures were identified or recommended in the Study.

 

9.1.1Moreover, a number of measures which are not directly associated with additional chlorine hazards were identified during the Study.  These measures were considered as appropriate measures to be implemented during the construction stage and were included in this EIA Report.

 

9.1.1As it is expected that the proposed water treatment process after the Water Treatment Works extension works would induce no increase of chlorine hazard in terms of storage or number of deliveries, the hazard assessment for the operational phase is not required in this EIA Study

STUDY TEAM

Study Team Organisation

Metcalf & Eddy will be leading the Assignment with technical support from specialists. Figure 5.1 shows the Study Team organisation chart.

Experiences and qualifications of key study team members of the EIA Study are outlined below and more fully described in the CVs in Appendix A.

Key Team Members

Project Direction and Management  

Project Director – K L Wong is Managing Director of M&E’s Hong Kong office who has more than 43 years of water and civil engineering experience.  He retired as Director of Water Supplies after 32 years service in WSD and is very familiar with the local supply systems and treatment works planning and design, especially the Shek Pik Reservoir, Tai Lam Chung Reservoir and Plover Cove Scheme. He has gained extensive experience in the design and construction of major water supply facilities including water treatment works, pumping stations, service reservoirs and water mains during his service in WSD and is also fully conversant with the day-to-day operation and maintenance of the WSD supply and distribution systems.  He is a water supply specialist and has on many occasions provided expertise advice on matters pertaining to treatment works, pumping stations, water mains and service reservoir design.  In his recent years of consultancy practice, he has been Project Director for many WSD projects, the more relevant ones being Investigation Study for In-situ Reprovisioning of Sha Tin WTW, Transfer Facilities in Butterfly Valley, Extension of Water Supply to Ma On Shan and Shau Kei Wan, and Replacement and Rehabilitation of Watermains Stage 1 Phase 1B Package 1 and Package 3 (D&C).

Project Manager – Bevis Mak is an Executive Director of M&E.  He has over 20 years practical experience in the planning, investigation, design and administration of multi-disciplinary water supply, environmental and sewage disposal projects, including the design of the Au Tau Water Treatment Works Stage I and II, the Waterworks Sludge Treatment and Transfer Facilities.  Other major projects included Pak Kong Water Treatment Works and Transfer Facilities, water quality studies on the effect of cryptosporidium and giardia in drinking water, effect of chloral hydrate in drinking water, feasibility of re-using grey water and treated effluent from secondary sewage treatment works, pressure management and its effect on leakage control, and Rehabilitation and Replacement of Watermains.  On the sewage and drainage side, he was responsible for the design and construction of the Sham Tseng Sewage Treatment Works, East Kowloon Sewage Stage II, North West Kowloon Sewage Stage II & III (Phase 1), Tolo Sewage Stage I Phase II.  He is also a specialist in construction contract law and was the consultant’s in house contract adviser on the HATS (previously SSDS) major tunnellng dispute between Government and the Contractor.   

 

Deputy Project Manager - Michael Leung is an Associate of M&E with 20 years of experience in water supply and other environmental engineering projects in Hong Kong and Australia.  Michael has extensive experience in managing projects for feasibility studies, design and tender documentation involving water treatment works, pumping stations, watermains and service reservoirs construction in Hong Kong, China and Australia. He was project manager for investigation projects of WSD mainlaying in Replacement and Rehabilitation of Watermains Stage 1 Phase 1B Package 3, Water Transfer Facilities in Butterfly Valley (using H2ONET for network analysis), and Tsuen Wan/Kwai Chung. Currently, he is project manager for Replacement and Rehabilitation of Watermains Stage 1 Ph 1B Package 1 and Water Supply to N-W Tuen Mun.  He has in depth knowledge of the operation of WSD’s water supply systems. 

 

Environmental Team

Environmental Team Leader – Josh Lam, an Associate of MEMCL, with extensive experience in environmental management, planning and impact assessment.  He is also an ecology and tree survey specialist. He has been managing and directing numerous multi-disciplinary environmental projects, ecological and conservation studies: Reconstruction of Catchwater and Upgrading of Slopes on Hong Kong Island and Lantau, Route10, Penny’s Bay Infrastructure Development, NENT Planning and Development, Northshore Lantau and International Theme Park Developments, San Tin Main Drainage Channel Improvements, Yuen Long/Kam Tin Sewage Disposal. 

Hazard Assessment – Matthew Ko is an Associate with MEMCL, has 11 years of environmental research and consulting. He has managed over numerous risk assessment projects for private and public clients, including the recent work for the Towngas Western Harbour Submarine Pipeline and Associated Station project.  He was the Environmental Team Leader for the EIA for Lai Ping Road, Shatin, Ngau Tam Mei Water Treatment Works, EIA for Kai Tak Airport North Apron Decommissioning, and Yau Tong Bay Reclamation.     

Environmental Impact Assessment – Jane Carbray is a Senior Environmental Consultant of MEMCL has over 9 years experience in EIA studies relating to water quality and waste management issues. She provided specialist inputs to projects such as San Tin EMDC, Penny’s Bay Infrastructure Development, Tai O Development, NNT Drainage Masterplan Study, Restoration of Shuen Wan and Urban Landfills, Wanchai Development Phase II, Feasibility Study for Intensification and Extension of Tseung Kwan O New Town, Yau Tong Bay Development and EPD Cumulative Impact Study and Strategic Sewage Disposal Scheme (SSDS) EIA. She has been also engaged in waterworks projects including environmental review for the PPFS of Extension of North Point Supply System, Replacement and Rehabilitation of Water Mains in Kowloon and NT South.

Air Quality & Noise Assessment – Anna Chung is a Senior Environmental Consultant of MEMCL has over 6 years experience in EIA studies major relating to air quality and noise issues. She provided specialist inputs to projects such as Hong Kong Cyber Port Project Development, South East Kowloon Development Feasibility Study, Tai O Development, Wanchai Development Phase II, D&C of Central – Wanchai Bypass and IECL, Sai Kung Sewage Treatment Works Phase II Upgrading, Outlying Islands Sewerage Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment & Disposal Facilities, and Feasibility Study for Intensification and Extension of Tseung Kwan O New Town.  

Ecological/Tree Specialist - Dr. David Gallacher, an Environmental Consultant of MEMCL who is an experienced ecologist with academic and practical experience in many aspects of terrestrial and aquatic ecology. Dr. Gallacher has extensive experience in tree survey, ecological review and impact assessment for terrestrial and stream habitats, flora and fauna.  Relevant recent projects include: Route 9, Route 10, Decommissioning of Cheoy Lee Shipyard, Landslide Mitigation Works Against Natural Terrain Hazards in Tung Wan and Shatin Heights, Construction of Tuen Mun North No. 2 Fresh Water Service Reservoir and Associated Mainlaying, Reconstruction of Catchwater Channels and Tunnels and Upgrading of Adjoining Slopes in Tai Lam Chung, Stage 1, Replacement and Rehabilitation of Water Mains in Hong Kong and Lantau Island.

Archaeologist/Cultural Heritage Impact Specialist – Dr Pamela Rogers, is a Consultant to MEMCL and is a qualified archaeologist and cultural heritage manager with more than 25 years experience mostly on the heritage of Hong Kong.  She has successfully completed a wide range of projects for both government and corporate clients, including assessments of New Territories drainage improvement schemes and several project sites in Lantau, such as Lantau N-S Road Link Study and Northshore Lantau Development Feasibility Study.  Dr. Rogers is a member of the Town Planning Board and is active in organisations promoting heritage management in Hong Kong.

Landscape & Visual Specialist - Salina Lee, is Landscape Architect of MEMCL and is a Registered Landscape Architect in Hong Kong with over 7 years of local experience.  She has extensive experience in impact assessment, tree survey and felling application, landscape masterplan, detailing and planting design, slope treatment, contract specification, tendering and administration, implementation of hard and soft landscaping works, site supervision, as well as architectural surface finish design, for a wide range of projects such as North Lantau Highway and Tiu Keng Leng Site Formation Works.

 


[1] The departures from the intention of construction activity

[2] How the particular activity is intended to execute

[3] The reasons why, and how, the deviations could occur 

[4] The results that follow from the occurrence of a deviation