Design and Construction Contamination Assessment Plan ...

The Government of the Hong Kong Special Administrative Region Water Supplies Department

Agreement No. CE 13/2009 (WS) In-situ Reprovisioning of Sha Tin Water Treatment Works – South Works – Design and Construction

Contamination Assessment Plan Final (Rev. 2)

In-situ Reprovisioning of Sha Tin Water Treatment Works – South Works

Design and Construction Water Supplies Department Contamination Assessment Plan (Final (Rev. 2))

AECOM Asia Co. Ltd. ii

Table of Content

Page

1 INTRODUCTION .................................................................................................................. 1

1.1 Project Background .................................................................................................. 1 1.2 Objectives ................................................................................................................ 2

2 ENVIRONMENTAL LEGISLATION, POLICIES, PLANS AND STANDARDS ....................... 3

3 ASSESSMENT METHODOLOGY......................................................................................... 4

4 LAND CONTAMINATION SITE APPRAISAL ....................................................................... 5

4.1 General Site Context ................................................................................................ 5 4.2 Geology and Hydrogeology .................................................................................... 12 4.3 Acquisition of Information from Government Departments ....................................... 13 4.4 Historical Information .............................................................................................. 14 4.5 Site Appraisal ......................................................................................................... 15 4.6 Identified Hotspots for Site Investigation ................................................................. 31

5 SAMPLING AND TESTING PLAN FOR SITE INVESTIGATION ......................................... 32

5.1 Site Investigation .................................................................................................... 32 5.2 Soil Sampling Method and Depth of Sampling ........................................................ 37 5.3 Strata Logging ........................................................................................................ 37 5.4 Free Product and Groundwater Level Measurement ............................................... 37 5.5 Groundwater Sampling ........................................................................................... 37 5.6 Sample Size and Decontamination Procedures....................................................... 38 5.7 QA/QC Procedures ................................................................................................. 38 5.8 Health and Safety ................................................................................................... 39

6 LABORATORY ANALYSIS ................................................................................................ 40

7 INTERPRETATION OF RESULTS ...................................................................................... 43

8 SCHEDULE OF SITE INVESTIGATION & REMEDIATION WORKS .................................. 46

9 POSSIBLE REMEDIATION OPTIONS ................................................................................ 47



AECOM Asia Co. Ltd. iii

List of Tables Table 4.1 Information of Registered Dangerous Goods Table 4.2 Information of Registered Chemical Wastes Table 4.3 Review of Aerial Photographs Table 4.4 Details of Chemicals Storage Areas Table 4.5 Details of Major Equipment Requiring Oil Replacement Table 4.6 Details of Factors That May Lead to Significant Land Contamination Table 4.7 Site Appraisal Results Table 4.8 Identified Buildings and Facilities with Potential Land Contamination Concerns Table 5.1 Sampling and Testing Plan Table 6.1 Parameters, Detection Limits and Reference Methods for Laboratory Analysis Table 6.2 Laboratory Testing Requirements for TCLP Analysis Table 7.1 Relevant RBRGs for Soil and Groundwater – Industrial Table 7.2 Relevant Screening Levels for Soil and Groundwater List of Figures Figure 1.1 Site Layout Plan Figure 4.1 Location of Spillage Incident on 15 March 2010 Figure 4.2 Potential Hotspot Figure 5.1 Schematic Layout Plan for Area A and Proposed Sampling Location Figure 5.2 Schematic Layout Plan for Area B and Proposed Sampling Location Figure 5.3 Schematic Layout Plan for Area C and Proposed Sampling Location Figure 5.4 Schematic Layout Plan for Area D and E and Proposed Sampling Location Figure 5.5 Schematic Layout Plan for Area F and Proposed Sampling Location Figure 5.6 Schematic Layout Plan for Area G and Proposed Sampling Location Figure 5.7 Schematic Layout Plan for Area H, I and L and Proposed Sampling Location Figure 5.8 Schematic Layout Plan for Area J and Proposed Sampling Location Figure 5.9 Schematic Layout Plan for Area K and Proposed Sampling Location Figure 5.10 Typical Design of Groundwater Well Appendices Appendix A Responses from Government Departments on Relevant Information Appendix B Selected Aerial Photos Appendix C Material Safety Data Sheet for Chemicals Used in STWTW Appendix D As-built Floor Plan of the Chemical House Appendix E Site Walkover Checklist Appendix F WSD’s Confirmation Letter Concerning the SI Works Schedule



AECOM Asia Co. Ltd. 1

1 INTRODUCTION

1.1 Project Background

1.1.1 AECOM Asia Co., Ltd (AECOM) was commissioned by Water Supplies Department (WSD) to undertake an Environmental Impact Assessment (EIA) for the in-situ reprovisioning of Sha Tin Water Treatment Works – South Works (hereinafter referred as the “Project”). The Project is about reprovisioning of the South Works of the existing largest water treatment facility in Hong Kong with a state-of-the art treatment process to enable a more reliable water supply to the territory.

1.1.2 Sha Tin Water Treatment Works (STWTW) is the largest treatment works in Hong Kong. The existing STWTW was initially commissioned in 1964 and subsequently extended in several stages until 1983 to its present capacity. It is the largest water treatment works in Hong Kong meeting about 30% of the total water demand of the territory. Although STWTW has a nominal capacity of 1227000 m3/day, it can only maintain a maximum daily output of about 1060000 m3/day due to the aging of plant and equipment which are approaching the end of their service life and require major renovation or replacement.

1.1.3 The key elements of the proposed works for the Project as the following:

isolation and decommissioning of the South Works which in essence involved the Clarifiers, Filters, Pumping Station and Clear Water Tanks, in phases if desirable, upon commissioning of Tai Po WTW Part 1 scheduled for end 2011;

reprovisioning of the South Works to the proposed reliable output of 550,000 m3/day,

the South Works FWPS, and common facilities including the Administration Building, Mainland East Laboratory, Alum Saturation Tanks and Chemical House. The treatment process shall have the capability to handle 3.0 mg/L ammoniacal nitrogen and 1.5 mg/L soluble manganese in raw water and be able to reduce the average chlorine consumption from the present level by at least 0.3 mg/L; and

all other associated civil, geotechnical, mechanical and electrical works including

provision of high voltage and low voltage switchboards for providing electricity supply to the reprovisioned South Works and the existing/future North Works to the ultimate capacity of 1,227,000 m3/day , environmental works, control and monitoring works, power supply and distribution works inclusive of works required to facilitate upgrading of power supply from CLP Power Hong Kong Ltd. (CLP), permanent and temporary access works, any modification and protection works to the existing equipment and structures necessary for completion of the works elements as listed in sub-clauses above.

1.1.4 The proposed in-situ reprovisioning works under this Project is located in the existing STWTW. The locations of the proposed works (the Site) are shown in Figure 1.1.

1.1.5 The implementation of the Project requires an environmental permit under the EIA Ordinance (EIAO). The EIA Study Brief, No. ESB-220/2011 (ESB) under Section 5(1) of the EIAO was issued by the Environmental Protection Department (EPD).

1.1.6 With a range of land uses along the Project area, there would be potential land contamination issues, in particular areas used for pumping station, alum saturators tanks, dangerous goods and chemicals storage areas and other potential contaminated site(s) identified in this EIA study. The ESB requires a land contamination assessment to be carried out, including the submission of a Contamination Assessment Plan (CAP), Contamination Assessment Report (CAR) and, if land contamination is confirmed, a Remediation Action Plan (RAP) to the Director of Environmental Protection (DEP) for endorsement. After completion of remediation works (if necessary), a Remediation Report (RR) to demonstrate adequate clean-up should be prepared and submitted to the Director




of Environmental Protection for endorsement prior to the commencement of any construction works within the site.

1.2 Objectives

1.2.1 The objectives of this CAP are to:

i. present the findings of the desk study and site appraisal on past and present land use activities that may lead to contamination;

ii. identify potential hotspots of land contamination for intrusive site investigation (SI); iii. propose a sampling and testing strategy for the SI of necessary; and iv. obtain EPD endorsement of CAP as required by the ESB.

1.2.2 A CAR will be prepared based on the SI results after the completion of SI works. Should

significant contamination be identified within the works areas, a RAP will be submitted as required in Section 3.4.4.5 of ESB, for formulation of necessary remedial measures.




2 ENVIRONMENTAL LEGISLATION, POLICIES, PLANS AND STANDARDS

2.1.1 Land contamination assessment shall be conducted in accordance with Section 3.4.4 of ESB and Section 3.1 and Section 3.2 (Potential Contaminated Land Issues) of Annex 19 “Guidelines for Assessment of Impact on Sites of Cultural Heritage and Other Impacts” of the “Technical Memorandum on Environmental Impact Assessment Process” (EIAO-TM).

2.1.2 Based on the EIAO-TM, the following land uses may have the potential to cause or have caused land contamination:

Oil installations including oil depots and petrol filling stations; Gas works; Power plants; Shipyards/boatyards; Chemical manufacturing/processing plants; Steel mills/metal workshops; Car repairing and dismantling workshops; and Dumping ground and landfill.

2.1.3 If the above land uses are identified, land contamination assessment shall be conducted

with reference to the “Guidance Note for Contaminated Land Assessment and Remediation” (Guidance Note) and “Practice Guide for Investigation and Remediation of Contaminated Land” (Practice Guide) issued by EPD. In addition, the Risk-based Remediation Goals (RBRGs) stipulated in the “Guidance Manual for Use of Risk-based Remediation Goals for Contamination Land Management” (Guidance Manual) issued by EPD shall be adopted as the criteria for assessing soil and groundwater contamination.




3 ASSESSMENT METHODOLOGY

3.1.1 In order to identify and evaluate the potential land contamination impacts associated with the Project, the following tasks have been undertaken:

Desktop study to review the current and historical land uses; and Site inspection to identify potential contaminated areas activities on site as necessary.

3.1.2 The following sources of information have been collated and reviewed for the desktop

study:

Aerial photographs from Lands Department; Hong Kong Geological Topography Map (Series: HGM20, 1:20,000 Scale) – Sheet No.

7 (Shatin, Edition 1, 1986); Information of dangerous goods for potentially contaminated areas from Fire Services

Department; and Records and photographs obtained from site visits.

3.1.3 Based on the desktop reviews and site appraisal, sampling locations and sampling depths

for soil and groundwater at the potential contaminated sites have been proposed for the SI works. This CAP also specifies the sampling and testing requirements for the SI works.

3.1.4 Upon completion of the SI works, the analytical results of the soil and groundwater should be interpreted using RBRGs. The nature, level and extent of the land contamination at the potential land contaminated sites will be evaluated and presented in the CAR. If contamination is found, appropriate remediation option will be recommended in the RAP.




4 LAND CONTAMINATION SITE APPRAISAL

4.1 General Site Context

4.1.1 The Site is a part of the existing STWTW, which is located at Keng Hau Road, Tai Wai, New Territories and covers a total area of approximately 5 hectares. The Site is situated in a generally rural residential setting. The Site is located on a flat terrain and surrounded by hills on its south, west and north direction. MTRC Eastern Railway and Old Beacon Hill Tunnel Shatin side entrance is aligned on the east side of the Site. Hin Keng Estate is located further to the east direction of the Site.

4.1.2 The layout of STWTW is shown in Figure 1.1, in which the portion comprising the Site has been shaded and this will be decommissioned as stated in the ESB.

4.1.3 Major buildings and facilities within the Site include:

1. Energy Dissipating Chamber; 2. Raw Water Inlet Channel, Overflow Channel, Dividing Chamber and its Extension; 3. Clarifiers No. 1-4 and associated Distribution Chamber; 4. Filter Beds (South Works) and Filtered Gallery (South Works); 5. Filtered Water Pumping Station (South Works); 6. Grit Trap and Washwater Recovery Tanks No. 1-3; 7. Chemical House and Lime Chloride Solution Processing Tank; 8. Chlorination House; 9. Alum Saturator Tanks; 10. Covered Storage Area (Workshops); 11. Open Storage Area; 12. Dangerous Goods Store and Chemical Waste Storage Area; 13. Generator House; 14. Transformer House; 15. Administration Building; 16. Staff Quarters Storage Compound; and 17. Bungalow (NTE1 Region & INSTRUMENT/M (NTE2)).

Water Treatment Process

4.1.4 Normally, raw water entering the STWTW firstly passes through the Raw Water Inlet Channel (Photo 4-1). The Raw Water Inlet Channel is designed with a zigzag shape, along which a Mixing Chamber is to allow in-line dosing of chemicals (Photo 4-2) including alum, lime and chlorine to be sufficiently mixed with the raw water stream in order to facilitate subsequent water clarification process.

Photo 4-1 Raw Water Inlet Channel

Photo 4-2 Chemicals (alum, lime and chlorine) Injection Points




4.1.5 In order to cope with excessive water head when water is fed from the High Island Reservoir, the Energy Dissipating Chamber was set up in 1978. Two numbers of energy dissipater valves with isolation valves are provided immediately upstream of the Raw Water Inlet Channel to dissipate this excess head prior to entry into the STWTW.

4.1.6 Water reaches the Dividing Chamber and its Extension at the end of the Raw Water Inlet Channel will be distributed to the Distribution Chambers in South Works and North Works. In South Works, water will be distributed to four 49m diameter circular sedimentation tanks, Clarifiers No. 1-4 (Photo 4-3). Polyelectrolyte may be required before water entering the Clarifier if high level of particulates is detected in the raw water to enhance clarification process.

Photo 4-3 Clarifier No.3

Photo 4-4 Filter Bed (South Works)

4.1.7 Supernatant from the Clarifiers will be discharged to Filter Beds (Photo 4-4) for further

removal of particulates from the process water. There are twenty two (22) Filter Beds and three (3) Filter Galleries in a combined Filter Block in the South Works. Pneumatic powered valves (Photo 4-5) and several air receivers (Photo 4-6) are installed at the basement floor of the Filter Galleries.

Photo 4-5 Pneumatic powered valves in the Filter Bed Gallery B/F

Photo 4-6 Air Receivers on Filter Beds Gallery B/F

4.1.8 On the other hand, settled sludge collected from the Clarifier will be discharged into the

Sludge Balancing Tank, which is not within the EIA Study Scope, for further sludge handling process.

4.1.9 Filter Beds are required to backwash regularly. Spent washwater from Filter Beds of both South and North Works will flow into a Grit Trap and Washwater Recovery Tanks No. 1-3 by gravity (Photo 4-7). This spent washwater will then be recycled back to the Inlet Works.




Photo 4-7 Grit Trap and Washwater Recovery Tanks

Photo 4-8 Filtered Water Pumps in the Pumping Station (South Works)

4.1.10 Treated water will be delivered to the community by the Pumps in the Filtered Water

Pumping Station (South Works) (Photo 4-8). There are eight (8) units of these pumps. Fluoride and chlorine will be dosed to the filtered water at this point. Moreover, lime may also be required for the filtered water for pH adjustment.

4.1.11 It is considered that the ground underneath these water tanks and flowing channels should not be contaminated by their operation.

Plant Rooms, Chemicals Processing and Storage Areas

4.1.12 Besides the afore-mentioned water channels and process tanks, there are some other facilities and buildings, used as control rooms, plant rooms, workshops, dangerous goods and chemical processing tanks, etc, within the Site.

4.1.13 The Chemical House (Photo 4-9) is located at the southern boundary of the STWTW. It is a 2 storey and 1 basement building. The upper floor (1/F) provides a storage area for dry process chemicals, including alum, lime, polyelectrolyte, lime chloride and sodium hexafluorosilicate (fluoride). There are a number of chemicals processing tanks founded on B/F (Photo 4-10), with openings on G/F, including four (4) tanks for lime solution, three (3) for alum solution, two (2) for polyelectrolyte solution and three (3) for fluoride solution. The preparation of fluoride solution is conducted inside enclosed rooms on G/F (Photo 4-11) and 1/F in view of its toxic characteristic. About sixty (60) pumps are installed on the B/F (Photo 4-12) and G/F to deliver chemicals for solution preparation and application to dosing points in the Raw Water Inlet Channel. Relatively small amount of engine oils are required for routine maintenance of these pumps.

Photo 4-9 Chemical House

Photo 4-10 Chemicals Processing Tanks (lime) on G/F of the Chemical House




Photo 4-11 Fluoride Dosing Room on G/F for Fluoride Solution Preparation

Photo 4-12 Chemicals pumps on B/F of the Chemical House

4.1.14 The lime chloride solution is prepared in small quantity in a fibreglass tank outside the

Filter Bed Gallery (South Works). The solution is used to provide supplementary sterilization in the event that the existing chlorination process is found insufficient.

4.1.15 There are four (4) exposed Alum Saturator Tanks No. 1 – 4 (Photo 4-13) at the south western boundary of the Project Site. Under normal practice, the ordered alum chemicals, in solid form, will be dissolved in these tanks until the designed concentration has been reached. Then this prepared alum solution will be dosed at the Raw Water Inlet Channel. There is a small pump house between Alum Saturator Tank No. 1 & No. 3, in which two (2) chemical feed pumps (Photo 4-14), are installed. These pumps require small amount of engine oil for routine maintenance.

Photo 4-13 Alum Saturator Tank No. 3

Photo 4-14 Chemicals pumps on B/F of the Pump House

4.1.16 The Chlorination House (Photo 4-15) is established in 1992 next to the South Works

Clarifier No. 3, which replaced the chlorination plant previously installed at the Chemical House. The Chlorination House currently stores 223 nos. One-tonne unit chlorine drums. This liquid chlorine will be processed by ten (10) drum handling bays for pre-chlorination and for post-chlorination. The Chlorination House also includes evaporators, chlorinators and dosing facilities. A recirculation sodium hydroxide solution scrubber system is also installed inside the Chlorination House as an emergency and contingency measure to handle liquid chlorine spillage incident. A generator set (Photo 4-16) is located in a covered house in the vicinity of the Chlorination House to supply power for the Chlorination House operation in case there is a failure of grid power supply. The generator is powered by diesel which is stored in the 1,200L diesel tank located at the bottom part of the generator body. The chlorine drum handling bays are pneumatically powered. The Chlorination House will not be reprovisioned under this Project.




Photo 4-15 Chlorination House

Photo 4-16 Backup Generator Set for Chlorination House Operation

4.1.17 There is a Covered Storage Area (Photo 4-17 – 4-19) established adjoining to the

Chlorination House, which is divided into two small workshops for NTE Region and Mechanical & Electrical Maintenance Division of STWTW. In general, the scale of maintenance works carried out in these workshops is small.

Photo 4-17 Covered Storage Area

Photo 4-18 Maintenance Workshop for STWTW NTE Region

Photo 4-19 Storage of Bulk Materials between Two Maintenance Workshops

Photo 4-20 Open Storage Area

4.1.18 Opposite to the Chlorination House, there is another Open Storage Area (Photo 4-20 &

4-21) for temporary storage of scrap materials, including idle pilot plant, discarded equipment and parts and single floor structure for storage of laboratory document, etc. A small portion of the Open Storage Area is currently designated as a storage area and workshop (Photo 4-22) for the contractor of North Works Accelerator No. 6 modification works.




Photo 4-21 Closer Look of Stored Materials in the Open Storage Area

Photo 4-22 Contractor Workshop on Open Storage Area

4.1.19 There is a Dangerous Goods Store (Photo 4-23 & 4-24) on the southeast boundary of the

Site. The Store comprises of three storage rooms, which are generally occupied and managed by NTE Region (responsible for operation in the STWTW), Mechanical & Electrical Maintenance Division (responsible for E&M works in the STWTW) and Water Science Division (responsible for process management and laboratory analysis in the STWTW). There is one chemical waste storage area installed between the storage rooms.

Photo 4-23 Dangerous Goods Store & Chemical Waste Storage Area

Photo 4-24 Fuel and lubricant oils storage in the NTE Region managed Dangerous Goods Store room

4.1.20 There is a generator (Photo 4-25) installed at the Generator House adjoining to the

Administration Building. This generator is used to provide backup power supply for the Filtered Water Pumps operation and all essential use around the Administration Building. The generator is powered by diesel and it has a fuel tank of 380L capacity on the lower part of its body. In addition, one additional fuel tank (Photo 4-26) of 480L capacity is installed in the Generator House.




Photo 4-25 Back-up Generator

Photo 4-26 Diesel Daily Tank of 480L capacity beside the Back-up Generator

4.1.21 There is also a transformer House (Photo 4-27), in which three transformers are installed

at a group at a covered house behind the Administration Building in close proximity of the Generator House. It is used to transform a power supply of 6,600V to 380V for use in STWTW.

Photo 4-27 Transformer House

Photo 4-28 Administration Building

4.1.22 The Administration Building (Photo 4-28) is located at the southeast corner of the initial

South Works established in 1964 and top of the main access road from the vehicular entrance gate. It is adjoining to and between the Filtered Water Pumping Stations (North Works) and (South Works). It is a 2-storey building. The STWTW main control room and administration office is on the upper floor (1/F) whereas the lavatories and store rooms are located on the ground floor.

4.1.23 There is a Staff Quarters located at the southeast end of the STWTW. Within the Staff Quarters area, there is a Storage Compound (Photo 4-29), which is currently used by the Headwork 1 (NTE) Section of the WSD as a sub-depot. Under the sheltered portion of the Compound, there are four compartments, including two gauze wire compartments for general equipment and tools, one room for staff’s lockers and general use and one locked room for chemicals storage, in which bleaching solution, paint and lubricants were kept.




Photo 4-29 Overview of the Storage Compound

Photo 4-30 Bungalow

4.1.24 The Bungalow (Photo 4-30) is located by the side of access road to the Chemical House

on the southwest side of the Dangerous Goods Store. The Bungalow is consisted of two rooms, one is occupied by the NTE Region and the other smaller one by INSTRUMENT/M (NTE2) Section, who is responsible for instrument/monitoring device operation and maintenance. The room occupied by the NTE Region is paved with vinyl flooring and used for storage of paint and various household cleansing agents, including soap and disinfectant cleaner. Regarding the room occupied by INSTRUMENT/M (NTE2), it is mainly used as a site office and for keeping spare parts of monitoring device.

4.2 Geology and Hydrogeology

Site Geology and Superficial Geological Deposits

4.2.1 According to the Hong Kong Geological Topography Map (Series: HGM20, 1:20,000 Scale) – Sheet No. 7 (Shatin, Edition 1, 1986), the Site is underlain by unsorted sand, gravel, cobbles and boulders; clay/silt matrix of Pleistocene and Holocene Epoch of Quaternary Period and Coarse-grained granite of Jurassic to Cretaceous Period of Mesozoic Era.

4.2.2 A review of previous ground investigation (GI) reports undertaken at or in the vicinity of the subject Site was conducted at the Civil Engineering and Development Department’s (CEDD) Geotechnical Information Library to obtain information about the geological and hydrogeological conditions of the Site.

Final Site Report for Landslide Study Site Investigation at Shatin Filter Beds, PWD Contract No. 416/79, by ENPACK (H.K.) Ltd. (1980) (CEDD’s Geotechnical Information Unit Report No. 02944)

Site Investigation Report for Marine Disposal of Sludges in Shatin Area, EDD

Contract No. GC/85/08, by Gammon (Hong Kong) Ltd. (1987) (CEDD’s Geotechnical Information Unit Report No. 09688)

Ground Investigation Report for Shatin Water Treatment Works New Chlorination House at Keng Hau Road, CESD Contract No. GC/89/06, by Enpack (Hong Kong) Limited (1990) (CEDD’s Geotechnical Information Unit Report No.13487)

Geotechnical Report for Proposed Foundation for Noise Barrier at KCRC Track

Chainage CH7 +075 to 7 +37 Hin Ken Estate, by Acer Consultants (Far East) Limited (1994) (CEDD’s Geotechnical Information Unit Report No. 22057)

Ground Investigation Report for Agreement No. CE 64/2002 (WS), In-situ Reprovisioning of Sha Tin Water Treatment Works, Phase I, Shatin, Ground Investigation, Contract No. GE/2001/13 by Geotechnics & Concrete Engineering (Hong Kong) Ltd. (2003) (CEDD’s Geotechnical Information Unit Report No.38380)




Second Round Engineer Inspections and Upgrading Works for WSD Slopes, 2002-2003 Programme - Design and Construction, WSD Agreement No. CE 77/2001(GE), by Maunsell Geotechnical Services Ltd. (2007) (CEDD’s Geotechnical Information Unit Report No.44977)

4.2.3 With reference to the above GI reports, superficial deposits (approximately 1m to 21.50m in

thickness) comprise clayey silt and coarse sand overlying subangular coarse grained granite cobbles, boulders and coarse gravel. In terms of the likelihood of downward migration of contaminants, these unconsolidated materials can be expected to exhibit high permeability and potential vertical migration of any liquid contaminants will not be significantly retarded. According to the general topography of the Site, ground level of the major area within the Site is around 27 to 36mPD.

4.2.4 GI report entitled Ground Investigation Report for Agreement No. CE 64/2002 (WS), In-situ Reprovisioning of Sha Tin Water Treatment Works, Phase I, Shatin, Ground Investigation, Contract No. GE/2001/13, issued in 2003, provides the most representative information relating to ground conditions in the EIA study area as the majority of the boreholes drilled in this assignment fell within the Project Site, either around the existing STWTW facilities, including the Chemical House, DG Store, Clarifiers, etc, or on the boundary. The general geological sequence comprises top soil and fill materials overlying colluviums and residual soil in turn overlying various grades of granitic rock. According to the borehole logs, groundwater strikes were not encountered during drilling, particularly in the boreholes around the existing STWTW facilities. Several boreholes, primarily on the boundary of the Project Site were completed as piezometers with the piezometer tips located between -18.23 and 36.44mpd. Gauged water levels were measured to be between 26 – 29mpd on the existing slopes on the south and west edges of the Project Site; and 18.52mpd in a piezometer located on the access road outside the Administration Building. Based on the spatial distribution of boreholes advanced and the soil and rock profiles described, shallow intergranular flowing groundwater is not anticipated to be encountered the majority of locations across the site and deeper groundwater is likely to flow via fractures in the solid rock.

4.3 Acquisition of Information from Government Departments

4.3.1 Environmental Protection Department (EPD), Fire Services Department (FSD) and WSD have been contacted for (i) history of chemical waste producers registration; (ii) spillage or release of chemical wastes within STWTW; (iii) records of dangerous goods storage license; and (iv) reported accidents of spillage/leakage of dangerous goods.

4.3.2 EPD and FSD’s replies on the request had been received and attached in Appendix A. WSD also provided their information via email. All the Information provided is summarized below.

Environmental Protection Department

4.3.3 EPD communicated with AECOM and transferred the request of information to WSD.

Fire Services Department

4.3.4 According to the information provided by FSD, there have been 5 types of registered DG kept in STWTW and their details are listed in Table 4.1. Among all these DG, only chlorine storage area falls within the Site boundary whereas the remaining DGs are kept in the North Works, which is outside the Site area.




Table 4.1 Information of Registered Dangerous Goods

Types of DG DG Category Quantity Storage Area Helium 2 6 nos. of 8.5m3 cylinder Cat.2 Dangerous

Goods Store near the Filter Bed at STWTW North Works

Nitrogen 2 5 nos. of 6.8m3 cylinder Argon 2 14 nos. of 6.8m3 cylinder Synthetic Air 2 2 nos. of 6.8m3 cylinder Chlorine 2 235 nos. of 1 tonne drum Chlorination House

4.3.5 As revealed by FSD, there was one fuel spillage incident occurred at the STWTW on 15 March 2010. In addition, FSD did not have any fire incident record for the Site.

Water Supplies Department

4.3.6 According to the information provided by WSD, Table 4.2 details the chemical waste generated on site. Among these chemical wastes, spent lube oil is kept in the Chemical Waste Storage Area within the Site whereas sodium hydroxide was discarded directly from the storage tank in the Chlorination House. Regarding the laboratory generated chemicals; they are kept in the existing WSD Mainland East Laboratory, which is outside the Site area.

Table 4.2 Information of Registered Chemical Wastes

Types Waste Producer Number

Storage Area

Acid 0056-759-W2285-02 WSD Mainland East Laboratory (STWTW North Works) Alkali

Solvent Heavy Metal Compound Spent lube oil 0056-759-W2282-03 Chemical Waste Storage Area Spent Sodium Hydroxide Chlorination House

4.3.7 Besides the spillage incident on 15 March 2010 as mentioned in FSD’s reply letter, WSD

indicated that there was no other recorded chemical spillage/leakage incident within the Site area.

4.3.8 Regarding the spillage incident, a crane truck overturned on the access road to Washwater Recovery Tanks during lifting of a heavy valve in the afternoon on that day. A small amount of diesel was leaked from the fuel tank of the truck on the paved road surface and flown into the surface channel on the side of road. The WSD’s subcontractor immediately blocked the channel and held all the leaked fuel, which was subsequently cleared off by the subcontractor. According to the information provided by WSD, including photos taken immediately after the incident and appraisal with the WSD staff responsible for handling the incident, there was only tiny amount of diesel spilled from the overturned truck on the road surface and consequently into a surface channel at which most of it was collected. However, there is a lawn area adjacent to the surface channel and it might be affected by the incident. The location of the incident was shown in Figure 4.1.

4.4 Historical Information

Review of Aerial Photographs

4.4.1 A review of the historical maps of Hong Kong and aerial photographs has been undertaken. The aim of this review is to evaluate potential contamination implication associated with any land use changes within the subject lots / facilities. The development history of these subject lots / facilities is summarized below and a list of aerial photographs reviewed has been provided in Table 4.3. Selected aerial photos are provided in Appendix B for reference.




Table 4.3 Review of Aerial Photographs

Year Height (Feet) Photograph Reference Number 1961* 30000 39 1963* 3900 5429 1969 ---- 2133 1974 4000 8308 1976 4000 13154 1980 4000 33115 1984* 4000 56840 1990 4000 A21052 1994 5000 A38161 2000 3000 CN27822 2004 4000 CW59341 2010 6000 RS02148

Source: Survey and Mapping Office, Lands Department * Aerial Photos provided in Appendix B

4.4.2 According to the earliest available aerial photograph (Ref. No. 39) taken in Year 1961, the

Site was not yet developed at that time. The area of the Site was a typical rural area and was generally covered with green vegetation.

4.4.3 The South Works, including Clarifiers, Filter Beds and Chemical House, were under construction as observed in the aerial photograph (Ref. No. 5429) taken in 1963. Nonetheless, the South Works started its operation in 1964 based on WSD’s information.

4.4.4 In reviewing the aerial photos, it was found that the Site was under continuous modification during the previous 47 years of operation. However, most of the existing buildings and facilities had not been further changed after construction.

4.4.5 According to the reviewed aerial photos, Covered Storage Area, Alum Saturator Tanks, Grit Chamber and Washwater Recovery Tanks were firstly found in the aerial photograph (Ref. No. 13514) taken in 1976.

4.4.6 Regarding the other major changes within the Site, Dangerous Goods Store was firstly found in the aerial photograph (Ref.: 56840) taken in 1984 and Chlorination House was under construction as found in the aerial photograph (Ref.: A21052) taken in 1990. As informed by the Site Staff, prior to construction and operation of the Chlorination House, there were three chlorination tanks serving for the purpose in the Chemical House. The three chlorination tanks were located on 1/F east wing of the House. There was a compartment room on G/F beneath these three tanks to contain any leaked chlorine solution in the event of any accidental spillage. All the three tanks had been demolished upon suspension of the old system and the area has been used for storage of other processing chemicals since then.

4.4.7 After 1994, the buildings and facilities were generally remained about the same as the existing settings.

4.5 Site Appraisal

4.5.1 Three site inspections were carried out in July and September 2011. During the site inspections, the Site was in normal operation except some particular locations which were temporarily suspended due to regular maintenance. The major focus of the site inspections was on all possible sources of land contamination within the Site.




4.5.2 The ground in these facilities/buildings as well as the access roads around the Site is usually covered with concrete or asphalt. The area around these facilities/buildings is normally covered with vegetation. The Site condition is neat and tidy and is considered properly managed. Furthermore, the Site is a water treatment works and one of the critical objectives is to protect the drinking water from contamination.

Storage of Chemicals 4.5.3 Chemicals used/stored in the Site area include:

Water treatment chemicals, e.g. alum, chlorine, fluoride, lime, lime chloride, polyelectrolyte;

Maintenance uses, e.g. lubrication oils, grease and transformer oil; Fuel, e.g. diesel; Laboratory chemicals and cleansing agents, e.g. acids, acetone; and General household cleansing agents, e.g. soap, metal cleaners.

4.5.4 These chemicals were stored in various locations within the Site area. Table 4.4 provides

the details of each chemicals storage area and relevant stored chemicals as observed during the site inspections.

Table 4.4 Details of Chemicals Storage Areas

Location Details of Stored Chemicals Dangerous Goods Store (NTE Region) (Site Area: ~32m2)

~3 nos. of drums (220L) of diesel ~110 nos. of plastic containers (18L – 30L) of lubrication oils >50 nos. of glass containers (3L – 10L) of methanol, acetone,

hexane, etc, in locked shelves (Owned by Water Science Division) >200 nos. of cans of butane in locked shelves (Owned by Water

Science Division)

Dangerous Goods Store (Mechanical & Electrical Maintenance Division) (Site Area: ~32m2)

~10 nos. of drums (220L) of transformer oil ~3 nos. of drums (220L) of diesel ~30 nos. of plastic containers (18L) of lubrication oils

Dangerous Goods Store (Water Science Division) (Site Area: ~25m2)

>1000 nos. of laboratory used chemicals, including acids, CDTA, sulphates, etc. kept in glass or plastic bottles (<5L) on shelves

~20 plastic bottles of laboratory used cleansing agents




Chemical House

>1000 bags (25kg – 750kg) of alum, polyelectrolyte and lime in powder form on 1/F of the Chemical House

~5 drums (40kg) of lime chloride on1/F of the Chemical House An enclosed room for storage of sodium hexafluorosilicate on1/F of

the Chemical House

Chlorination House 235 drums (1 tonne) of liquid chlorine on G/F of the Chlorination House

1 tank of sodium hydroxide served as a mitigation measure to chlorine spillage/leakage on G/F of the Chlorination House

Staff Quarters Storage Compound

1 drum (220L) of larvicidal oil under the sheltered area ~10 drums (18L) of bleaching solution on the floor in a storage room ~8 cans (4L) of paint on the shelves in a storage room ~35 plastic containers (1L) of lubrication oils and grease on the

shelves in a storage room 1 drum (~100kg) of solid form lime chloride under the sheltered area

Bungalow (Store Room occupied by NTE Region)

~60 cans (4L) of paint on the shelves A number of household cleansing and maintenance agents,

including soap, wax, detergents, on the shelves

4.5.5 As detailed in Section 4.3.4 and Table 4.1, all FSD registered dangerous goods have been

kept outside the EIA study area, except chlorine drums in the Chlorination House, within STWTW. However, there are also some other types of dangerous goods, including diesel, acetone, etc., kept in the Dangerous Goods Store in a small quantity that is exempted from registration to FSD.




4.5.6 Regarding the water treatment chemicals kept in the Chemical House, only powder-form lime chloride and hexafluorosilicate are considered as toxic chemicals. Actually, all the applied chemicals, including lime, alum, lime chloride, polymer and hexafluorosilicate, are supplied in solids form and kept on 1/F of the Chemical House. Therefore, it is unlikely that the storage of these chemicals could induce any land contamination because they are not in direct contact with ground soil level. The material safety data sheet of these chemicals used in STWTW is annexed in Appendix C.

4.5.7 The Staff Quarters Storage Compound is currently occupied by Headwork 1 (NTE) Section of WSD. As observed during a site inspection on 22 September 2011, there were some kinds of chemicals kept in an enclosed storage room, including paint and lubrication oils on shelves as well as bleaching solution on the floor. Besides, there was a drum of larvicidal oil and a drum of lime chloride stored outside the storage room under the sheltered area. All these chemicals will be applied offsite. During the site inspection, minor leakage of lubricant was found underneath an idle small-sized portable generator set in the middle of the room for staff’s lockers and general use, which is paved with concrete. According to the staff from Headwork 1 (NTE) Section, this equipment was malfunctioned and temporarily kept in the room.

4.5.8 The two rooms in the Bungalow are occupied by the NTE Region and INSTRUMENT/M (NTE2) Section. The room occupied by the NTE Region is paved with vinyl flooring and used for storage of paint and various household cleansing agents, including soap and disinfectant cleaner. Most of these chemicals were not opened and all of them were kept on the shelves properly. Regarding the room occupied by INSTRUMENT/M (NTE2), the stored goods were usually spare parts of monitoring device.

4.5.9 According to WSD, there was one abandoned underground storage facility for diesel located next to the Transformer House beside the Administration Building. This fuel tank had been disused and emptied for more than ten years ago and was later filled with concrete in 2010.

Maintenance Activities with Handling of Lubrication Oil, Transformer Oil and Fuel

4.5.10 There are a large number of electrical and mechanical equipment in STWTW. Regular maintenance and servicing is essential for the equipment to maintain normal operation, during which replacement of lubrication and engine oils is one of the common procedures.

4.5.11 The procedures for oil replacement simply include delivery of oils from storage area to operation area, draining out of waste oils from the equipment and then refilling, and finally store these oils back to the Chemical Waste Storage Area.

4.5.12 Major equipment requiring oils replacement during maintenance and servicing within the Site are provided in Table 4.5.




Table 4.5 Details of Major Equipment Requiring Oil Replacement

Location Equipment Involved Chemicals

Chemical House

~60 nos. of chemical dosing and transfer pumps, 20 nos. on the G/F and 40 nos. on B/F

~10 nos. of mixers installed above the chemical

processing tanks 1 set of lifting crane and 1 silo 1 idle lime delivery equipment, comprising a conveyor belt

and a mixing system

Lubrication oil Grease

Clarifiers (South Works) No. 1-4

A few pieces of motors for operation of clarifier and scraper above water in each Clarifier


Filtered Water Pumping Station (South Works)

8 nos. of filtered water pumps for supplying treated water to the consumers

6 nos. of backwash pumps responsible for regular cleaning of the Filter Beds


Alum Saturator Tanks Pump House

2 nos. of alum transfer pumps on B/F of Pumps House 1 no. of mixers installed above each Alum Saturator

Tanks


Chlorination House Backup Generator

1 no. of generator set installed in a sheltered house near the Covered Storage Area for backup power supply to the Chlorination House

Fuel, diesel Lubrication oil Grease

Generator House

1 no. of generator set installed in the Generator House to provide backup power for the facilities around the Administration Building, with a daily tank feeding diesel fuel.

Fuel, diesel Lubrication oil Grease

Transformer House beside Administration Building

3 no. of transformers are installed in a sheltered house behind the Administration Building to transform 6,600V to 380V for the STWTW operation

Transformer oil

4.5.13 No oil replacement was observed during the site inspections except a drum of spent oil

was being delivered to the Chemical Waste Storage Area by a WSD subcontractor during the site inspection on 28 July 2011. In general, the areas around the equipment as listed in Table 4.5 were clean and free from oily sheen.




4.5.14 For the equipment installed above water processing or chemical processing tanks, e.g. motors for scraper operation in the Clarifier and mixers above Alum Saturator Tanks, land contamination is considered not likely due to oil replacement for these equipments.

4.5.15 Depending on equipment application and capacity, quantity of lubrication oil required for each type of equipment shall be different. The pumps/mixers in the Chemical House require tiny amount of lubrication oil for their maintenance when compared with filtered water pumps in the Filtered Water Pumping Station (South Works). On the other hand, there are as high as 60 pieces of pumps in the house but just 8 pieces of filtered water pumps. These two equipment set-ups are quite typical in the STWTW and the factors based on these two set-up types that may lead to significant land contamination due to oil replacement activities are also different. Table 4.6 shows a summary of these factors.

Table 4.6 Details of Factors That May Lead to Significant Land Contamination

Location General Features Factors Lead to Land Contamination

1 Chemical House

Large number of small-sized chemical pumps *

Relatively less quantity of lubrication oil required for each piece of equipment

More frequent oil replacement and associated activities, e.g. oils delivery More frequent equipment installation and dismantling

Prolonged oil leakage from malfunctioned equipment

Malpractice in equipment maintenance, which involved oil replacement

Less cautious in oil replacement works

Less cautious in rectifying small-scale oil leakage/spillage incident

Alum Saturator Tanks Pump House *

2

Filtered Water Pumping Station (South Works)

Only a few pieces of equipment within the works area

Large quantity of oil is normally required for each piece of equipment

One accidental spillage or leakage incident may result in significant contamination

Malpractice in equipment maintenance, which involved oil replacement

Relatively more cautious when carrying out maintenance and servicing works

Chlorination House Backup Generator

Generator House

Transformer House beside Administration Building

* There are only two pieces of Alum Transfer Pumps in the Pump House.

4.5.16 The Covered Storage Area is currently used as two maintenance workshops for Mechanical & Electrical Maintenance Division and NTE Region. The Open Storage Area is mainly used for storage of scraped materials but a small portion of the Area has been allocated to a subcontractor as a workshop and storage area. Both Storage Areas were paved with concrete.

4.5.17 There was no maintenance activity undertaken at these workshops during the site inspection. However, as informed by the Site staff, there would only some minor scale maintenance works be conducted in these workshops.




Chemical Processing Tanks

4.5.18 There are 12 nos. of Chemicals Processing Tanks (including 2 polyelectrolyte, 3 fluoride, 3 alum and 4 lime processing tanks) and 4 nos. of Alum Saturator Tanks inside and outside the Chemical House respectively. All the chemicals processing tanks are concrete structured.

4.5.19 It is anticipated that the possible land contamination pathway will be leakage of chemical solutions through the cracks in the concrete tanks into the soil underneath.

4.5.20 Besides, upon dissolving into water and being heavily diluted in the processing tanks, these chemicals’ hazards should have become minimal and are readily dosed in the raw water stream to function. In consideration of minimal health concerns of these chemicals solutions, it is believed that land contamination due to leakage of these chemicals is not likely though it could not be verified during the site inspection.

4.5.21 Owing to the health hazard of fluoride containing chemical, sodium hexafluorosilicate, two enclosed rooms are established for storage and dosing of this chemical on 1/F and G/F respectively. The three fluoride processing tanks are also located in adjacent to the enclosed room on G/F. In view of the health hazard of hexafluorosilicate, further SI should be considered beneath the fluoride dosing room on G/F and at the bottom of the fluoride processing tanks. An as-built floor plan of the Chemical House showing the facilities and equipment for fluoride processing as well as other chemicals pumps areas is annexed in Appendix D.

4.5.22 Lime chloride is only occasionally used in small quantity. In addition, the operation is primarily a manual activity and under full supervision. Therefore, it is unlikely that land contamination would be a concern from this activity.

Other Materials Storage Area

4.5.23 The Open Storage Area was used to keep all the scraped materials, including idle prefabricated houses, replaced valves, pilot plant set-up, scrap metals, empty chemicals drums, etc., which could be recycled. As observed during the site inspection, these waste materials were not stored in any particular order. These materials and any residues left in them might cause contamination.

4.5.24 The findings of the site appraisal are summarised in Table 4.7.

4.5.25 An interview was conducted with several site staff in order to understand the general operation and maintenance works within the Site as well as any potential contamination spots. Record of interview on site staff during site inspections is provided in Appendix E.




Table 4.7 Site Appraisal Results

Location Approx.

Site Area (m2)

Description Potential Contamination Impact Reference Necessity for

Further Investigation?

Raw Water Inlet Channel

N/A - The Raw Water Inlet Channel is constructed of concrete receiving raw water from the reservoirs.

- The Channel was in use during the site inspection. - Chemicals, including alum, lime and chlorine gas, were

dosed to the raw water stream at the chemical dosing point in the Channel.

- Not likely to cause adverse land contamination impact

Photo 4-1 & 4-2

No

Clarifiers (South Works)

No. 1-4

N/A - The Clarifiers in South Works are well constructed of concrete.

- All the four Clarifiers were in operation during the site inspection.

- Polyelectrolyte solution was dosed at the centre part in the clarifier to facilitate the clarification process. This chemical and the chemicals added upstream in the Raw Water Inlet Channel were at very low concentration.


Photo 4-3 No

Energy Dissipating Chamber

N/A - The Chamber comprises two partitioned water tanks and one operation room.

- It was not in use during the site inspection. - There are two energy dissipating valves in this Chamber

and no mechanical equipment is deployed.


- No

Filter Beds (South Works)

& Filter Galleries

N/A - The Filter Beds and Filter Galleries are constructed of concrete.

- There are 22 Filter Beds and 3 Filter Galleries in the existing South Works. Only some Filter Beds in the South Works were in operation while the remaining Filter Beds were either under maintenance or idle.

- At the basement of the Filter Galleries, there were valves along pipework for flow control and all of them were powered pneumatically. There were a few compressed air receivers at the basement but air supply was from the air compressors located in the North Works, which was outside


Photo 4-4 to 4-6

No




Location Approx.

Site Area (m2)



the Study Scope. - According to the Site Staff, the equipment does not require

engine oils or lubricant in these two locations.

Grit Trap and Washwater Recovery

Tanks No. 1-3

N/A - The Grit Trap and all Washwater Recovery Tanks are constructed of concrete.

- Both Grit Trap and Washwater Recovery Tanks No. 1-3 were in operation during the site inspection.

- The washwater, which passed through these two facilities, was generated from backwash processes of Filter Beds. It was observed that the washwater was quite clear and not polluted.

- Submersible pumps are deployed to pump the recovered washwater back to the Sludge Balancing Tanks for further treatment.

Not likely to cause adverse land contamination impact

Photo 4-7 No

Filtered Water Pumping

Station (South Works)

540 - The Filtered Water Pumping Station (South Works) is paved with structured concrete for installation of heavy Filtered Water Pumps.

- The Pumping Station is located adjoining to the Administration Building. In the Pumping Station, there are eight (8) Filtered Water Pumps responsible for supplying treated water to the consumers. In addition, there are six (6) backwash pumps responsible for regular cleaning of the Filter Beds.

- During the site inspection, the Pumping Station was in normal operation, in which some pumps were under regular maintenance and servicing. The suspended pumps were displayed with proper labels to indicate their status.

- These pumps required lubricant oil and grease for regular maintenance and servicing. There was no sign of oil spillage or contamination observed.

- No storage of chemicals/waste chemicals was observed in the Pumping Station.

- Housekeeping was proper as observed during the site

- Relatively large quantity, when compared with general pumps, of lubricant would be required for maintenance and servicing of the filtered water pumps.

- Although the Station is generally paved with intact concrete and no sign of spillage was observed during the site inspection, considering that the Pumping Station has been in operation for nearly 50 years since commencement of the South Works, further investigation is necessary to assess the potential impact due to leakage or spillage of lubricant.

Figure 5.1 and Photo 4-8

Yes




Location Approx.

Site Area (m2)



inspection. There was no sign of chemicals spillage in the Pumping Station.

Chemical House & Lime

Chloride Processing

Tank

2,600 - The Chemical House is a concrete structure, and it is primarily used for chemicals (alum, lime, polyelectrolyte, lime chloride and fluoride) storage and processing.

- On G/F of the House, there are 12 processing tanks for chemicals solution preparation, including alum, lime, polyelectrolyte and fluoride.

- There are also 20 and 40 nos. of chemical pumps which required small amount of lubricant oil, on G/F and B/F of the House respectively.

- The 1/F of the House is used of dry chemicals storage. A silo for lime storage, some lifting equipment and a standby conveyor belt unit are installed on this floor.

- The fluoride contained chemicals (sodium hexafluorosilicate) and dosing equipment are kept and operated in enclosed rooms on 1/F and G/F of the House respectively. The fluoride solution processing tanks are located in adjacent to the enclosed room on the G/F.

- A lime chloride solution processing tank was idle outside the Filter Bed Galleries (South Works). The solution was only occasionally required.

- Chemicals storage was generally satisfactory, except some fine chemical particles left on the floor of 1/F of the House.

- No oil stain was observed on the floor around the pumps and valves on G/F and B/F.

- There were a few water puddles on the floor of B/F and in the surface channel beside the chemicals pumps on the same floor.

- There was no sign of incineration / burning activities observed in the Chemical House.

- Although there are a number of chemical processing tanks on the B/F, these chemicals are generally of less concern, except fluoride. The fluoride level in the soil beneath the fluoride dosing room and fluoride processing tanks may be a concern to the workers during construction and operation phase. Further SI for fluoride level on this area is necessary.

- Lubricant oil was required for maintenance of over 60 nos. of chemical pumps distributing on B/F and G/F. In general, the House is paved with intact cover. However, in consideration that this operation has been undertaken for almost 50 years in this House, further investigation is necessary to check the land contamination impact aroused by the lubricant oil, except the pumps installed on the tank walls on G/F.

- The walls of all chemical processing tanks are about 2.5m high of entire concrete structure. Since all pumps, installed on top of the tank walls, are isolated from the ground, the land contamination

Figure 5.2 and Photo 4-9 to 4-12

Yes




Location Approx.

Site Area (m2)



issues from these pumps would be minimal and hence, no further investigation is proposed for these pumps.

Alum Saturator Tanks & Pump

House

20 - The Alum Saturator Tanks are constructed of concrete. The Pump House is also a small concrete structure consisting of G/F and B/F.

- All the Alum Saturator Tanks were in operation during the site inspection. Mixers were operating in the middle of the tank to facilitate alum solution preparation.

- The Pump House is located between the Alum Saturator Tank No. 1 & No. 3. A control panel and an air compressor were installed on G/F while three dosing pumps were installed on B/F of the house. Tiny amount of lubricant oil is required for equipment maintenance.

- A small bund was erected surrounding the pumps area. A few water puddles were observed within the bunded pumps area.

- No oil stain was observed on the floor on G/F and B/F.

- Both Alum Saturator Tanks & Pump House have been in operation for about 25 years.

- In consideration of the historical information and existing operation in the Alum Saturator Tanks, no land contamination impact was identified.

- On the other hand, lubricant oil replacement is required for the pumps on B/F of the Pump House. As any spillage or leakage of lubricant oil might cause land contamination, further investigation is necessary.

Figure 5.3 and Photo 4-13 & 4-14

Yes

Chlorination House & Backup

Generator Set

30 (Backup

Generator Set)

- The Chlorination House is a single storey concrete structured building, in which over 200 one-tonne unit chlorine drums were tidily stored in it during the site inspection. Ten (10) drum handling bays are installed in it. There are also separate rooms for evaporators and dosing facilities within the building.

- A sodium hydroxide scrubber system, comprising a big tank of sodium hydroxide solution and associated pipework is installed at the main entrance. The system will be in operation for any chlorine spillage incident.

- A generator set is installed inside a sheltered house in close vicinity of the Covered Storage Area to provide necessary backup power supply for the Chlorination House

- Based on historical information, existing operation in the Chlorination House, it is anticipated that the operation of the Chlorination House would not induce significant land contamination issues.

- On the other hand, the area underneath the generator set may be contaminated due to leakage or spillage of fuel and lubricant. As such, further investigation is necessary for


Yes




Location Approx.

Site Area (m2)



operation. It is powered by diesel which is stored in the 1,200L diesel tank on the lower part of the generator body.

- No storage of chemicals/waste chemicals was observed inside the sheltered house for the Generator Set.

- No oil stain was observed on the floor around the Generator Set.

the above area.

Covered Storage Area (Maintenance Workshops)

500 - The whole Covered Storage Area is paved with concrete. - It is currently used as a Maintenance Workshop and divided

into two small workshops, which are managed by the NTE Region and Mechanical & Electrical Maintenance Division separately.

- These two workshops are used for small scale maintenance works and storage of equipment and tools.

- The area between the two small workshops was used for storage of bulky size materials. In general, both workshops were neat and tidy as observed during the site inspection.

- Small amount of paint and lubricant was kept inside the workshops for operational purpose.

- No oil stain was observed on the floor in the workshops.

- As the Covered Storage Area is mainly used as workshops, the activities inside the workshops, as well as accidental spillage and leakage of chemicals may cause land contamination. Therefore, further investigation is necessary.


Yes

Open Storage Area

1,400 - The Open Storage Area is paved with concrete. - There are three idle prefabricated houses and two

underground valve pits within the Area. A small portion of the Open Storage Area is also allocated for a subcontractor to set up a small on-site workshop and storage area.

- The Area is primarily used for storage of materials, which was found obsolete from the process and pending for recycling. During the inspection, the types of materials kept in the Open Storage Area included replaced valves, pilot plant set-up, scrap metals, empty chemicals drums, etc.

- There was no operating equipment inside the Area. No storage of chemicals/waste chemicals was observed on the Area.

- The Open Storage Area has been used for about 15 years as a storage area for scrap materials. Contaminants, including residual chemicals (fuel or lubricant) in the scrap equipment parts, scrap metals fines, etc, may cause contamination to the soil beneath the area. Therefore, further investigation is necessary.


Yes




Location Approx.

Site Area (m2)



- No oil stain was observed on the Area. - There was no sign of incineration / burning activities

observed on the Area.

Dangerous Goods Store and Chemical Waste Storage

Area

100 - There were three separate concrete structured rooms in the Dangerous Goods Store, which are occupied by NTE Region, Mechanical & Electrical Maintenance Division works and Water Science Division of STWTW. As informed by the site staff, some of the materials owned by Water Science Division, including methanol and butane, are kept in the storage room managed by the NTE Region.

- All the Dangerous Goods Store rooms were locked and managed by staffs from relevant sections

- The materials stored in the NTE Region managed Dangerous Goods Store included drums of petrol, diesel, engine oil, lubricant oil and some Water Science Division owned chemicals, mainly consisting of 4L size of methanol, ethanol, hexane, toluene and small can-size of butane in a locked shelf cabinet.

- The materials stored in the Mechanical & Electrical Maintenance Division managed Dangerous Goods Store primarily included bulk size of engine oil (18L size) and transformer oil (220L size).

- The materials stored in the Water Science Division managed Dangerous Goods Store are the chemicals and cleansing agents required for laboratory analysis and operation. In general, these chemicals were kept in small bottles and tidily placed on the shelves.

- There is a Chemical Waste Storage Area located between the Dangerous Goods Store rooms. It was observed that about 10 drums of waste engine oil or lubricant were properly stored in it.

- No oil stain was observed on the floor in the Dangerous Goods Store and Chemical Waste Storage Area.

- As observed during the site inspection, the Dangerous Goods Store and Chemical Waste Storage Area were paved with intact concrete and managed by properly by the Site Staff. However, in consideration that the Dangerous Goods Store has been in use for almost 30 years, any accidental spillage or leakage of chemicals or dangerous goods may result in land contamination. Therefore, further investigation is necessary.


Yes




Location Approx.

Site Area (m2)



Generator House

18 - The Generator House is located in the Administration Building. There is one generator installed in the House to provide backup power supply to the facilities around the Administration Building, including filtered water pump house, control room and all other essential usages.

- The generator has a fuel tank of capacity 380L on the lower part of the generator body. In addition, one daily tank of capacity 480L is installed above ground in the Generator House. A drip tray is installed beneath the 480L fuel tank, which is further protected by a concrete bunding to minimize impact of spillage incident.

- During the inspection, the Generator House was generally maintained properly. The drip tray, concrete bunded area and floor area beneath the generator was dry.

- Besides diesel, there was no other chemical stored in the House.

- There was no sign of spillage of diesel on the floor in the House.

- In view of significant quantity of diesel stored inside the equipment and Generator House, any spillage or leakage of diesel as well as lubricant oil for the equipment may cause contamination. Therefore, further investigation is necessary.


Yes

Transformer House beside Administration

Building

30 - Three transformers are located in the Transformer House behind the Administration Building, next to the Generator House. They are operated by the Mechanical & Electrical Maintenance Division. The transformers serve to transform 6,600V to 380V for the STWTW operation.

- The transformers are installed inside a sheltered house. The sheltered house and surrounding area is paved with concrete.

- No storage of chemicals/waste chemicals was observed inside the sheltered house.

- No oil stain was observed on the floor around the Transformer House.

- Transformer oil is required for proper operation of the equipment. Any leakage or spillage of this oil may cause land contamination. Therefore, further investigation is necessary to assess the area beneath the Transformer House.


Yes

Lawn beside Access Road to Washwater

25 (Likely

affected

- A crane truck overturn incident happened at this location on 15 March 2010. According to photos taken immediately after the incident and appraisal with staff responsible for the

- In consideration of the small quantity of leaked fuel, well structured covering on road

Section 4.3.8, Figure 4.1 & 5.8

Yes




Location Approx.

Site Area (m2)



Recovery Tanks (Scene of the Spillage

Incident)

area) incident, a small amount of diesel was leaked from the fuel tank of the truck on the paved road surface and flown into the surface channel on the side of road. The WSD’s subcontractor immediately blocked the channel and held all the leaked fuel, which was subsequently cleared off by the subcontractor.

- The scene of the spillage incident was inspected during the site visits and there was no oil stain or residual noted on the road and in the surface channel.

surface and surface channel, as well as immediate remediation by WSD and its subcontractor, it is anticipated that land contamination impact to the soil beneath the road and surface channel should be minimal.

- As part of the overturned crane truck laid on lawn beside the surface channel, the soil might be affected by the leaked fuel.

Staff Quarters Storage

Compound

240 - The Storage Compound is currently used by the Headwork 1 (NTE) Section of the WSD as a sub-depot for storage of equipment, tools and chemicals, including bleaching solution, paints and lubricant oils. They have operated this Storage Compound for more than 16 years.

- The Storage Compound is partially covered. Beneath the sheltered portion, there are four compartments, including two wire fenced compartments for storage of small equipment and tools, one room for staff’s lockers and general use and one locked room for storage of afore-mentioned chemicals.

- In the locked room, bleaching solution was kept on the floor, paint and lubricants were kept on the shelves. All these chemicals will be applied offsite.

- There was a drum of larvicidal oil and a drum of lime chloride kept outside the storage room under the sheltered area. These chemicals will be applied offsite. Black and brown stain patches were observed on the floor outside the locked room.

- The room for staff’s lockers and general use was paved with concrete. During the site inspection, minor leakage of lubricant was found underneath an idle small-sized portable generator set in the middle of the room. According to the WSD staff, this equipment was malfunctioned and

- Based on the site inspection, there were chemicals, including lubricants, kept in the locked room. The potential land contamination concerns may include leakage or improper handling of stored chemicals.

- Minor leakage of lubricant and stain patches was identified within the Storage Compound.


Yes




Location Approx.

Site Area (m2)



temporarily kept in the room.

Bungalow (NTE Region & INSTRUMENT

/M (NTE2))

30 - The Bungalow was consisted of two separate rooms, one was occupied by the NTE Region and the other smaller one by INSTRUMENT/M (NTE2) Section.

- The room occupied by the NTE Region was paved with vinyl flooring and used for storage of paint and various household cleansing agents, including soap and disinfectant cleaner.

- The other room for INSTRUMENT/M (NTE2) Section is used for storage of spare parts of instrument/monitoring device.

- The chemicals stored in the Bungalow are generally for household use inside the NTE Region room. There will not be any application of these chemicals inside the Bungalow. As such, adverse land contamination issue is not likely.

Photo 4-30 No

Disused Diesel Storage Tank

4 - There was one abandoned underground storage facility for diesel located next to the Transformer House beside the Administration Building.

- This fuel tank had been disused and emptied for more than ten years ago. It was backfilled with concrete in 2010.

- The potential contamination hotspots may include soil and groundwater surrounding and underneath the disused diesel storage tank.

Section 4.5.9 & Figure 5.7

Yes




4.6 Identified Hotspots for Site Investigation

4.6.1 According to the findings of the desktop review and site inspection as summarized in Table 4.7, land contamination concerns were identified for the buildings / facilities as shown in Table 4.8 and Figure 4.2 and further SI is considered necessary for these buildings/facilities.

Table 4.8 Identified Buildings and Facilities with Potential Land Contamination Concerns

Area ID Location A Filtered Water Pumping Station (South Works) B Chemical House, Fluoride Dosing Room, Fluoride Processing Tanks and Pumps

Area inside Chemical House

C Pump House of Alum Saturator Tanks D Generator Set for Chlorination House E Covered Storage Area (Maintenance Workshop) F Open Storage Area and Contractor Workshop G Dangerous Goods Store and Chemical Waste Storage Area H Generator House I Transformer House near Administration Building J Lawn beside Access Road to Washwater recovery Tanks (The Scene of Crane Lorry

Overturn Incident)

K Staff Quarters Storage Compound L Disused Diesel Storage Tank




5 SAMPLING AND TESTING PLAN FOR SITE INVESTIGATION

5.1 Site Investigation

5.1.1 Based on the historical information reviewed and site observation, a total of 44 sampling locations are proposed at the identified potential hotspots and to assess the site conditions. The number of sampling locations proposed is generally according to the Guidance Note and Practice Guide.

5.1.2 The full scale sampling strategy recommended in the Practice Guide is adopted, except Areas C, D, H, I and J as there were only few small-scale potential contamination sources (e.g. tanks, generators, transformers, pumps, etc). For Areas A, B, E, F, G, K and L, the sampling locations are generally proposed to be evenly distributed across the potential contaminated sources. The indicative location plans of the proposed SI sampling locations are illustrated in Figures 5.1 to 5.9. However, as the facilities were in operation during inspection, any signs of contamination underneath the potential contaminated sources were not able to be observed. The exact sampling locations of the SI shall be determined on site and subject to fine adjustment based on ground conditions and site specific conditions (e.g. locations, presence of foundations, underground utilities, delivery pipes and services).

5.1.3 In general, the potential contamination sources within the Project site will be chemicals storage and application, as well as open storage area on the ground surface, except one disused fuel storage tanks. In consideration that most of the potential contamination sources are generally from activities/storage of chemicals on/above the ground level, small quantity of chemicals stored or under application as well as proper operation and management within a water treatment works, contamination, if any, should follow a pathway from surface to deeper underground. As such, it is anticipated that a termination depth of 6m, if no groundwater is encountered, shall be sufficient to capture any contamination. Therefore, the termination level of most boreholes is proposed to be either 6m beneath ground surface or, when encountering groundwater, 3 m below the groundwater table, whichever is shallower.

5.1.4 The selection of potential chemicals of concern (COCs) recommended for laboratory analysis at each proposed sampling location is referenced to the nature of historical and current use of each area, chemicals frequently used or stored, the Guidance Note, Practice Guide and Guidance Manual. The sampling and testing plan are summarized in Tables 5.1.




Table 5.1 Sampling and Testing Plan

Area ID/ Size Proposed Sampling Location/ Sampling ID1 Sampling Method Sample Matrix/ Depth2

Parameters to be Tested3 Petroleum

Carbon Ranges

VOC4 SVOC4 Heavy Metals4 Other

Filtered Water

Pumping Station (South Works)

A (~540 m2)

Four sampling location beneath the pumps at Filtered Water Pumping Station (South Works) A1 to A4 (Figure 5.1)

Borehole to 3 m below the groundwater table or 6m bgs

Soil

0.5 m bgs, 1.5 m bgs, 3.0 m bgs, and further at 3.0 m intervals upon encountering groundwater or 6m bgs whichever is shallower, and above GW level if present.

X X X - -

GW If present^ X X X - -

Chemical House

B (~2,600 m2)

One sampling location at the Fluoride Dosing Room inside Chemical House B1 (Figure 5.2)


Soil


- - - - Fluoride

GW If present^ - - - - Fluoride Three sampling locations at Fluoride Processing Tanks inside Chemical House B2 to B4 (Figure 5.2)

Hand tools Soil 0.5m below the bottom of the tank - - - - Fluoride

Five sampling locations beneath the pumps for chemicals delivery inside Chemical House B5 to B9 (Figure 5.2)


Soil


X X X - -


Two sampling locations beneath the pumps for fluoride inside Chemical House B10 & B11 (Figure 5.2)


Soil


X X X - Fluoride

GW If present^ X X X - Fluoride






Carbon Ranges


Pump House of Alum

Saturator Tanks

C (~20m2)

One sampling location beneath the pump at Pump House of Alum Saturator Tanks C1 (Figure 5.3)


Soil


X X X - -


Generator Set for

Chlorination House

D (~100m2)

One sampling location at generator set for Chlorination House D1 (Figure 5.4)


Soil


X X X Lead -


Covered Storage Area (Maintenance

Workshop) E

(~500 m2)

Four sampling locations inside Covered Storage Area (Maintenance Workshop) E1 to E4 (Figure 5.4)


Soil


X X X Full List -

GW If present^ X X X Mercury -

Open Storage and

Contractor Workshop

F (~1,400 m2)

Eight sampling locations inside the Open Storage and Contractor Workshop F1 to F8 (Figure 5.5)


Soil


X X X Full List -

GW If present^ X X X Mercury -






Carbon Ranges


Dangerous Goods Store and Chemical

Waste Storage Area

G (~100 m2)

Two sampling locations inside Dangerous Goods Store G1 and G4 (Figure 5.6)


Soil


X X X Lead -

GW If present^ X X X - - Two sampling locations inside Dangerous Goods Store and Chemical Waste Storage Area G2 and G3 (Figure 5.6)


Soil


X X X Lead PCBs

GW If present^ X X X - PCBs

Generator House

H (~18m2)

One sampling location beneath two aboveground diesel tanks at Generator House H1 (Figure 5.7)


Soil


X X X Lead -


Transformer House

I (~30m2)

One sampling location beneath the Transformer House near Administration Building I1 (Figure 5.7)


Soil


- - - - PCBs

GW If present^ - - - - PCBs Lawn beside Access Road to Washwater

Recovery Tanks

J (~25m2)

One sampling location at the lawn where overturn incident occurred. J1 (Figure 5.8)


Soil


X X X Lead -







Carbon Ranges


Staff Quarters Storage

Compound K

(~240m2)

Two sampling locations in the locked room and at the stain patch outside the locked room K1 and K2 (Figure 5.9)


Soil


X X X Full List -

GW If present^ X X X Mercury - One sampling location in the middle of the room for staff’s locker K3 (Figure 5.9)


Soil


X X X Lead -


Disused Diesel

Storage Tank L

(~4 m2)

Four sampling locations at each side of Disused Diesel Storage Tank and one sampling location at the bottom of Disused Diesel Storage Tank or its casing L1 to L5 (Figure 5.7)

Hand Tools Soil Side walls at mid-depth of tank and 0.5m below the bottom of tank or its casing X X X Lead -

Remarks: 1. Please refer to Figures 5.1 to 5.9 for locations. 2. bgs = Below Ground Surface; GW=groundwater 3. X = testing proposed 4. Full list refers to the parameters as shown in Table 2.1 – RBRGs for Soil & Soil Saturation Limit and Table 2.2 – RBRGs for Groundwater and Solubility Limit under VOCs, SVOCs and Metals in the

Guidance Manual. BTEX include benzene, toluene, ethylbenzene and xylenes. Since RBRG value of Benzo(a)anthracene, Benzo(a)pyrene, Benzo(g,h,i)perylene, Benzo(k)fluoranthene, bis-(2-Ethylhexyl)phthalate, Dibenzo(a,h)anthracene, Indeno(1,2,3-cd)pyrene and Phenol

were not available for groundwater, the captioned chemicals parameters would not be tested in groundwater sample. ^ Samples will only be collected if groundwater is encountered during SI works.




5.2 Soil Sampling Method and Depth of Sampling

5.2.1 All soil boring / excavation and sampling should be supervised by a land contamination specialist.

5.2.2 Borehole should be undertaken by means of dry rotary drilling method, i.e. without the use of flushing medium, to prevent cross-contamination during sampling. For safety reasons, an inspection pit should be excavated down to 1.5m below ground to inspect for underground utilities at the proposed borehole location. Disturbed soil samples should be collected at depth of 0.5m bgs. Soil boring using drill rigs should then be performed from depth of 1.5m to the maximum boring depth. Undisturbed U100/U76 soil samples should be collected at depths from 1.5m afterwards. Groundwater sample should be collected at the level of groundwater (if encountered). The deepest depth of sampling should be of 3m below the groundwater table or 6m bgs, whichever is shallower. Where there are suspected signs of contamination, extra samples should be taken for laboratory analysis.

5.2.3 In the event that rotary drilling cannot be applicable at the proposed sampling locations due to site constraints (e.g. insufficient head room or accessibility of drilling rigs), alternative sampling e.g. using trial pit or hand augering methods will be adopted. In that case, disturbed soil samples, using stainless steel hand tools, will be taken at 0.5m, 1.5m and 3.0m below the prevailing ground level in order to delineate the vertical profile of contamination.

5.2.4 At each sampling location/depth, sufficient quantity of soil sample (as specified by the laboratory) should be taken. All soil samples should be uniquely labelled. Backup samples should be retained and stored at 0 - 4 ºC in laboratory.

5.3 Strata Logging

5.3.1 Strata logging for boreholes should be undertaken during the course of drilling/digging and sampling by a qualified geologist. The logs should include the general stratigraphic description, depth of soil sampling, sample notation and level of groundwater (if encountered). The presence of rocks/boulders/cobbles and foreign materials such as metals, wood and plastics should also be recorded.

5.4 Free Product and Groundwater Level Measurement

5.4.1 The thickness of any free product and ground water level if present at sampling locations should be measured with an interface probe. The free product if encountered in sufficient amount should be collected for laboratory analysis to determine the composition.

5.5 Groundwater Sampling

5.5.1 It is proposed to collect groundwater samples if groundwater is encountered at the sampling locations.

5.5.2 For each proposed borehole sampling location, a groundwater sampling well should be installed into the boreholes if groundwater is encountered or agreed by the land contamination specialist. A typical design of a groundwater monitoring well is shown in Figure 5.10. After installation of the monitoring wells, the depth to water table at all monitoring wells should be measured at the same time with an interface probe in order to delineate the groundwater table contours at the subject site. Well developments (approximately five well volumes) should be carried out to remove silt and drilling fluid residue from the wells. The wells should then be allowed to stand for a day to permit groundwater conditions to equilibrate. Groundwater level and thickness of free product layer, if present, should be measured at each well before groundwater samples are taken.

5.5.3 Prior to groundwater sampling, the monitoring wells should be purged (at least three well volumes) to remove fine-grained materials and to collect freshly refilled representative groundwater samples.




5.5.4 After purging, one groundwater sample should then be collected at each well using Teflon bailer and decanted into appropriate sample vials or bottles in a manner that minimizes agitation and volatilization of VOCs from the samples. All samples should be uniquely labelled.

5.5.5 Immediately after collection, groundwater samples should be transferred to new, clean, laboratory-supplied glass jars for sample storage/transport. The sampling glass jars should be of “darken” type. Groundwater samples should be placed in the glass jars with zero headspace and promptly sealed with a septum-lined cap. Immediately following collection, samples should be placed in ice chests, cooled and maintained at a temperature of about 0-4ºC until delivered to the analytical laboratory.

5.6 Sample Size and Decontamination Procedures

5.6.1 All equipment in contact with the ground should be thoroughly decontaminated between each excavation, drilling and sampling event to minimise the potential for cross contamination. The equipment (including drilling pit, digging tools and soil/groundwater samplers) should be decontaminated by steam cleaning or high-pressure hot water jet, then washed by phosphate-free detergent and finally rinsed by distilled / deionised water.

5.6.2 Prior to sampling, the laboratory responsible for analysis should be consulted on the particular sample size and preservation procedures that are necessary for each chemical analysis.

5.6.3 The sample containers should be laboratory cleaned, sealable, water-tight, made of glass or other suitable materials with aluminium or Teflon-lined lids, so that the container surface will not react with the sample or adsorb contaminants. No headspace should be allowed in the containers which contain samples to be analysed for VOCs, Petroleum Carbons Range or other volatile chemicals.

5.6.4 The containers should be marked with the sampling location codes and the depths at which the samples were taken. If the contents are hazardous, this should be clearly marked on the container and precautions taken during transport. Samples should be stored at between 0-4 ºC but never frozen. Samples should be delivered to laboratory within 24 hours of the samples being collected and analysed within the respective retention period but should not more than 10 days.

5.7 QA/QC Procedures

5.7.1 QA/QC samples should be collected in the following frequency during the SI. Chain of Custody protocol should be adopted.

1 equipment blank per 20 samples for full suite analysis as shown in Table 6.1 (excluding PCBs testing); and

1 field blank per 20 samples for full suite analysis as shown in Table 6.1 (excluding PCBs testing);

1 duplicate soil sample per 20 soil samples and 1 duplicate groundwater sample per 20 groundwater samples for corresponding parameters analysis as shown in Table 6.1; and

1 trip blank sample per 10 trips for petroleum carbon range C6-C8 and BTEX.

5.7.2 Based on the sampling and testing plan as outlined in Table 5.1, there would be roughly 152 soil samples and 36 groundwater samples. The total number of equipment blanks, field blanks and duplicate samples would therefore be approximately 10 each; whereas number of trip blanks will be dependent of the number of trips for sample delivery.




5.8 Health and Safety

5.8.1 The specific safety measures to be taken depend on the nature and content of contamination, the site conditions and the regulations related to site safety requirements. Workmen Compensation Insurance and third party insurance must be provided for the SI.

5.8.2 Extreme care should be exercised when toxic gases or other hazardous materials are encountered. Any abnormal conditions found shall be reported immediately to the safety officer and the land contamination specialist.

5.8.3 The SI contractor shall establish and maintain a Health and Safety Plan before commencement of the SI that will include the following:

(a) Instruction of works on work procedures, safe practices, emergency duties, and applicable regulations;

(b) Regularly scheduled meetings of the workers in which the possible hazards, problems of the job, and related safe practices are emphasized and discussed;

(c) Good housekeeping practices; and (d) Availability of and instruction in the location, use and maintenance of personal

protective equipment. 5.8.4 The SI Contractor shall maintain equipment and supplies reasonably required in an

emergency, including lifesaving, evacuation, rescue and medical equipment in good working order and condition at all times. The SI Contractor shall use all reasonable means to control and prevent fires and explosions, injury to personnel and damage to equipment of property. Without limiting the foregoing, the SI Contractor shall:

(a) Maintain proper safety devices, barriers to minimize hazards during performance of the work;

(b) Prohibit smoking and open flames and the carrying of matches and lighters; (c) Develop and maintain a written emergency plan applicable to the Work and Site; (d) Maintain equipment in good operating condition and have emergency and first aid

equipment ready for immediate use, where applicable; (e) Conduct equipment tests to ensure that equipment is properly placed and in good

operating condition, and that workers are able to respond to emergency situations; (f) Require all workers employed or retained by the Contractor, or a subcontractor, to at

all time wear clothing suitable for existing work, weather and environmental conditions; and

(g) The personnel are required to wear respirator and gloves for vapour exposure protection, if necessary. Safety helmet and protective boots should be worn.

5.8.5 Concerning the hazardous nature of sodium hexafluorosilicate, special attention should be provided for all the workers involved in the SI works at the sampling locations of Fluoride Dosing Room, Fluoride Processing Tanks and Fluoride pumps inside Chemical House (Sampling Locations B1, B2 to B4, B10 & B11).




6 LABORATORY ANALYSIS

6.1.1 Laboratory analysis is proposed in order to screen the presence of potential contaminants that are of concern at the Site. Table 6.1 summarizes the parameters, the minimum requirement of the reporting limits and reference methods for the laboratory analyses of soil and groundwater samples for this land contamination study.

Table 6.1 Parameters, Detection Limits and Reference Methods for Laboratory Analysis

Item Parameter

Soil Groundwater Reporting

Limit (mg/kg) or otherwise specified

Reference Method*

Reporting Limit

(µg/L) or otherwise specified

Reference Method*

VOCs 1 Acetone 50 USEPA 8260 500 USEPA 8260 2 Benzene 0.2 5 3 Bromodichloromethane 0.1 5 4 2-Butanone 5 50 5 Chloroform 0.04 5 6 Ethylbenzene 0.5 5 7 Methyl tert-Butyl Ether 0.5 5 8 Methylene Chloride 0.5 50 9 Styrene 0.5 5 10 Tetrachloroethene 0.04 5 11 Toluene 0.5 5 12 Trichloroethene 0.1 5 13 Xylenes (Total) 2 20 SVOCs 14 Acenaphthene 0.5 USEPA 8270 2 USEPA 8270 15 Acenaphthylene 0.5 2 16 Anthracene 0.5 2 17 Benzo(a)anthracene 0.5 NA 18 Benzo(a)pyrene 0.5 NA 19 Benzo(b)fluoranthene 0.5 1 20 Benzo(g,h,i)perylene 0.5 NA 21 Benzo(k)fluoranthene 0.5 NA 22 bis-(2-Ethylhexyl)phthalate 5 NA 23 Chrysene 0.5 1 24 Dibenzo(a,h)anthracene 0.5 NA 25 Fluoranthene 0.5 2 26 Fluorene 0.5 2 27 Hexachlorobenzene 0.2 4 28 Indeno(1,2,3-cd)pyrene 0.5 NA 29 Naphthalene 0.5 2 30 Phenanthrene 0.5 2 31 Phenol 0.5 NA 32 Pyrene 0.5 2 Metals 33 Antimony 1 USEPA 6020 NA NA 34 Arsenic 1 NA 35 Barium 1 NA 36 Cadmium 0.2 NA 37 Chromium III^ 1 By calculation NA 38 Chromium VI 1 APHA 3500Cr: D NA 39 Cobalt 1 USEPA 6020 NA 40 Copper 1 NA 41 Lead 1 NA




Item Parameter

Soil Groundwater Reporting

Limit (mg/kg) or otherwise specified

Reference Method*

Reporting Limit

(µg/L) or otherwise specified

Reference Method*

42 Manganese 1 NA 43 Mercury 0.2 APHA 3112B 0.5 APHA 3112B 44 Molybdenum 1 USEPA 6020 NA NA 45 Nickel 1 NA 46 Tin 1 NA 47 Zinc 1 NA Petroleum Carbon Ranges 48 C6 - C8 5 USEPA

8015/8260 20 USEPA

8015/8260 49 C9 - C16 200 500 50 C17 - C35 500 500 PCBs 51 PCBs 0.1 USEPA 8270 1 USEPA 8270 Fluoride 52 Fluoride 1 APHA 4500F: C 100 APHA 4500F: C

Notes: NA = Not Applicable ^ Chromium III is quantified by calculation based on Chromium VI and Total Chromium measured under HOKLAS

accredited methods. * Alternative testing methods with accreditation by HOKLAS or its Mutual Recognition Arrangement partners are also

accepted.

6.1.2 For sampling and laboratory analyses, chain of custody procedure should be included as QC/QA procedure.

6.1.3 All laboratory analyses for soil and groundwater samples shall be conducted by a Hong Kong Laboratory Accreditation Scheme (HOKLAS) accredited laboratory. In addition, all laboratory test methods must be accredited by HOKLAS or one of its Mutual Recognition Arrangement partners.

6.1.4 For considering the option to dispose at landfill, laboratory analysis using Toxicity Characteristics Leaching Procedure (TCLP) for relevant parameters for three impacted samples as shown in Table 6.2 shall be carried out in accordance with the Practice Guide.

6.1.5 In general, if contamination is found, in-situ remediation measures and possible recycling and reuse of remediated materials should be considered as the preferred remediation options whereas ex-situ remediation the second. Offsite disposal to landfill should only be considered as the last resort. Nonetheless, any contaminated soil requiring disposal to landfill has to meet the Landfill Disposal Criteria for Contaminated Soil, in terms of Toxicity Characteristics Leaching Procedure (TCLP) limits as in Table 4.4 of the Practice Guide and follow the procedures of contaminated soil disposal in Table 4.5 of the Practice Guide.




Table 6.2 Laboratory Testing Requirements for TCLP Analysis

Parameter Test Methods* Detection limit (mg/L) Landfill Disposal Criteria TCLP Limit (ppm)

Antimony (Sb)

USEPA 1311 and 6020A

2 150 Arsenic (As) 2 50 Barium (Ba) 2 1000 Beryllium (Be) 1 10 Cadmium (Cd) 1 10 Chromium (Cr) 1 50 Copper (Cu) 2 250 Lead (Pb) 3 50 Nickel (Ni) 1.5 250 Selenium (Se) 0.2 1 Silver (Ag) 2 50 Thallium (Ti) 1 50 Tin (Sn) 2.5 250 Vanadium (V) 4 250 Zinc (Zn) 10 250 Mercury (Hg) 0.2 1

* Equivalent internationally recognized standard methods might also be used.




7 INTERPRETATION OF RESULTS

7.1.1 With reference to the Guidance Note, interpretation of results should make reference to the Guidance Manual. The soil and groundwater samples collected for this study will be compared with Risk-based Remediation Goals (RBRGs) as stipulated in Table 2.1 and Table 2.2 of the Guidance Manual.

7.1.2 The RBRGs are developed based on a risk assessment approach to suit the local environmental conditions and community needs in Hong Kong. Decisions on contaminated soil and groundwater remediation are based on the nature and extent of the potential risks that are posed to human receptors as a result of exposure to chemicals in the soil and/or groundwater. RBRGs are developed for four different land use scenarios reflecting the typical physical settings in Hong Kong under which people could be exposed to contaminated soil and groundwater. A description of each land use scenario is as follows:

Urban residential – Sites located in an urban area where main activities involve habitation by individuals. The typical physical setting is a high rise residential building situated in a housing estate that has amenity facilities such as landscaped yards and children’s playgrounds. The receptors are residents who stay indoors most of the time except for a short period each day, during which they are outdoors and have the chance of being in direct contact with soil at landscaping or play areas within the estate.

Rural residential – Sites located in a rural area where the main activities involve habitation by individuals. These sites typically have village-type houses or low rise residential blocks surrounded by open space. The receptors are rural residents who stay at home and spend some time each day outdoors on activities such as gardening or light sports. The degree of contact with the soil under the rural setting is more than that under the urban setting both in terms of the intensity and frequency of contact.

Industrial – Any site where activities involve manufacturing, chemical or petrochemical processing, storage of raw materials, transport operations, energy production or transmission, etc. Receptors include those at sites where part of the operation is carried out directly on land and the workers are more likely to be exposed to soil than those working in multi-storey factory buildings.

Public parks – Receptors include individuals and families who frequent parks and play areas where there is contact with soil present in lawns, walkways, gardens and play areas. Parks are considered to be predominantly hard covered with limited areas of predominantly landscaped soil. Furthermore, public parks are not considered to have buildings present on them.

7.1.3 In addition to the RBRGs, screening criteria (soil saturation limits, Csat, developed for Non-aqueous Phase Liquid [NAPL] in soil and water solubility limits for NAPL in groundwater) for the more mobile organic chemicals must be considered to determine whether a site requires further action.

7.1.4 Based on the Study Brief, the future land uses of the Site would be water treatment facilities. According to the Guidance Manual, the corresponding RBRGs land use for public utility will be “Industrial”, which will be adopted as the assessment criteria for this land contamination assessment, unless otherwise specified. Relevant soil and groundwater RBRGs level for this land contamination study including the Soil Saturation Limit and the Solubility Limit are presented in Table 7.1.




Table 7.1 Relevant RBRGs for Soil and Groundwater – Industrial

Chemical Soil (mg/kg) Groundwater ( g/L)

RBRGs for Industrial

Soil Saturation Limits (Csat)

RBRGs for Industrial

Solubility Limits

VOCs Acetone 10,000 *** 10,000,000 *** Benzene 9.21 336 54,000 1,750,000 Bromodichloromethane 2.85 1030 26,200 6,740,000 2-Butanone 10,000 *** 10,000,000 *** Chloroform 1.54 1100 11,300 7,920,000 Ethylbenzene 8,240 138 10,000,000 169,000 Methyl tert-Butyl Ether 70.1 2380 1,810,000 *** Methylene Chloride 13.9 921 224,000 *** Styrene 10,000 497 10,000,000 310,000 Tetrachloroethene 0.777 97.1 2,950 200,000 Toluene 10,000 235 10,000,000 526,000 Trichloroethene 5.68 488 14,200 1,100,000 Xylenes (Total) 1,230 150 1,570,000 175,000 SVOCs Acenaphthene 10,000 60.2 10,000,000 4,240 Acenaphthylene 10,000 19.8 10,000,000 3,930 Anthracene 10,000 2.56 10,000,000 43.4 Benzo(a)anthracene 91.8 NA NA NA Benzo(a)pyrene 9.18 NA NA NA Benzo(b)fluoranthene 17.8 NA 7,530 1.5 Benzo(g,h,i)perylene 10,000 NA NA NA Benzo(k)fluoranthene 918 NA NA NA bis-(2-Ethylhexyl)phthalate 91.8 NA NA NA Chrysene 1,140 NA 812,000 1.6 Dibenzo(a,h)anthracene 9.18 NA NA NA Fluoranthene 10,000 NA 10,000,000 206 Fluorene 10,000 54.7 10,000,000 1,980 Hexachlorobenzene 0.582 NA 695 6,200 Indeno(1,2,3-cd)pyrene 91.8 NA NA NA Naphthalene 453 125 862,000 31,000 Phenanthrene 10,000 28 10,000,000 1,000 Phenol 10,000 7260 NA NA Pyrene 10,000 NA 10,000,000 135 Metals Antimony 261 NA NA NA Arsenic 196 NA NA NA Barium 10,000 NA NA NA Cadmium 653 NA NA NA Chromium III 10,000 NA NA NA Chromium VI 1,960 NA NA NA Cobalt 10,000 NA NA NA Copper 10,000 NA NA NA Lead 2,290 NA NA NA Manganese 10,000 NA NA NA Mercury 38.4 NA 6,790 NA Molybdenum 3,260 NA NA NA Nickel 10,000 NA NA NA Tin 10,000 NA NA NA Zinc 10,000 NA NA NA Petroleum Carbon Ranges C6 - C8 10,000 1000 1,150,000 5,230 C9 - C16 10,000 3000 9,980,000 2,800 C17 - C35 10,000 5000 178,000 2,800




Dioxins / PCBs PCBs 0.748 NA 5,110 31 Note: NA - Not Available *** indicates that the Csat value/ solubility limit exceeds the ‘ceiling limit’ therefore the RBRG applies,

7.1.5 As the parameter Fluoride is not available in the RBRG list, another guideline “US Environmental Protection Agency Regional Screening Levels for Chemical Contaminants at Superfund Sites” (RSL) which has been widely used in other countries for initial soil screening for remediation should be adopted for assessing land contamination for Fluoride.

7.1.6 For groundwater, the RSL for tap water should be applied. For soil, the “ceiling limit" of 104 mg/kg applicable for relatively less toxic inorganic in soil (i.e. fluoride in this case) should be adopted. The relevant screening levels for soil and groundwater in this Project are presented in Table 7.2.

Table 7.2 Relevant Screening Levels for Soil and Groundwater

Chemical Soil (mg/kg) Groundwater (µg/L) Fluoride 10,000 1,500




8 SCHEDULE OF SITE INVESTIGATION & REMEDIATION WORKS

8.1.1 The SI for land contamination will be carried out by drilling of boreholes or construction of trial pits for the collection of soil and groundwater samples. One important factor to consider about the Site is that it is a part of the water treatment works and a secure and safe water supply is crucial to the operation of the whole water treatment works.

8.1.2 The locations of SI have been identified in Section 5 of this CAP. These locations include chemicals processing tanks, open and covered storage areas, water and chemicals delivery pumping systems, Dangerous Goods Store, backup generators and transformers. Generally, all the sampling locations are underneath the equipment and processing tanks.

8.1.3 As the SI works might cause process interruption and potential contamination of drinking water, it is, therefore, not possible to be conducted during the operational period of STWTW. The confirmation letter from WSD regarding these concerns is annexed in Appendix F.

8.1.4 Hence, it is proposed to conduct the SI in the beginning of the decommissioning works when the operation of the concerned location has been ceased and it is also safe to conduct investigation works.

8.1.5 After completion of the site investigation, a Contamination Assessment Report (CAR) shall be submitted to EPD for approval. The CAR shall provide background information of the Project and findings during preparation of CAP. The CAR shall also report the site investigation programme and results, results interpretation and recommendations for further investigations and/or remediation works.

8.1.6 If land contamination is confirmed within the Site, a Remediation Action Plan (RAP) which formulates remedial measures shall be submitted to EPD for endorsement. The remediation works should be undertaken according to the approved RAP. A Remediation Report (RR), demonstrating completion of remedial actions, should be prepared and submitted to EPD for approval prior to the commencement of construction works at the contaminated areas.




9 POSSIBLE REMEDIATION OPTIONS

9.1.1 According to the Practice Guide, the need to remediate the Site would be determined based on the findings of the site investigation and presented in the CAR. The appropriate remediation methods should be identified suitable for the site conditions and the contaminants requiring remediation in the RAP. The following factors should be considered when evaluating the remediation options:

Nature and level of contamination; Extent of contamination; Site characteristics; Site constraints; and Time available for remediation.

9.1.2 The actual nature, level and extent contamination can only be evaluated through SI. Nonetheless, Table 4.1 and Table 4.2 of the Practice Guide list out the remediation options that may be applicable to the Site. The remediation methods mainly divide in two categories, in-situ and ex-situ. The appropriate remediation methods for the Site would be selected based on the criteria set in the Practice Guide, actual contamination condition, construction programme and availability of selected remediation methods.

9.1.3 If feasible, in-situ / ex-situ remediation measures and possible recycling and reuse of remediated materials are the preferred remediation options, whereas excavation and landfill disposal is only considered as the last resort.

9.1.4 This assessment has examined the potential contaminating land uses within the Site. It also covers potential impacts of the contamination on future use. The assessment involved site appraisal and desktop review. Site investigation will be carried out at the decommission stage of the Site due to site access and sensitive nature of the water works. Based on the findings in site investigation, if any contamination is found, appropriate remediation measures shall be identified and carried out before construction commenced, so as to clean up the Site to the relevant RBRGs. With the remediation and mitigation measures in place, the potential land contamination impacts to the sensitive receptors and future use as water treatment facilities are thus not considered to be insurmountable.

FIGURES

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Open Storage

CUL CUL

CUL

Road

Road

Roa

d

FP

H

H

L

H

L

RCP

3H in TinStreet

TS

TS

TS

Ka Yin House

Lion

Roc

k Tu

nnel

Offic

e

(Tra

nspo

r t De

partm

ent)

14

16

18

20

7

40

40

60

40

40

80

60

40

40

100

60

60

60

80

8080

80

80

100

RC

P

Gas W

orks

TEI LUNG HAU

Sha Tin Treatment Works

CUL

CUL

PipelineWT

TankPipeline

Filter Beds

Filter Beds

CUL

CUL

Filter Beds

WIPApr 2010

WIP Apr 2010

CUL

CUL

CUL

CUL

Nullah

FP FB

FP

RoadCW

FP

Road

FP

FP

CW

FP

Road

FP FP

FP

Ram

p

Ramp

Railw

ay Tunnel (Disused)

Railw

ay Tunnel

Road

FP

EW

FB

F

L L

L

LL

L

HH L

LLL

H

L

EH

L

HET

H E

L

ET

H

H

L

L

L

L

L

H

L

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R

R

R

R

Pod

ium

80

1 60

140

120

80

60

100

80

60

40

110

100

80

60

40

40

60

40

40

Luk Hop Village

CUL

CUL

CUL

CUL

CUL

CUL

CUL

CUL

CULCUL

CUL

WT

CUL

CUL

CUL

CULTunn

el P

orta

l

PO

SHA TIN H

EIGHTS

TUN

NEL

TAIP

ORO

AD-

SHA

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HEI

GHT

S

El e v a t e d Roa d

EWCW

CW

FP

FP

FP

RoadFP

L

L L

L

L

L

L

L

L

LL

LL

E

L

LLL L

L

LL LL

LL

LL L

L

L

LL

L

L

L

L

L

L

L

H

H

L

TS

TS

TS

TS

Adm

inis

trat io

n Bu

ildin

g

Garage Workshop

TS

668

60

40

40

40

40

60

80

60

80

100

80

80

80

801 00

1 20

Open Storage

CUL CUL

CUL

Road

Road

Roa

d

FP

H

H

L

H

L

RCP

3Hin TinS t reet

TS

TS

TS

Ka Yin House

Lion

Rock

Tun

nel O

ffice

(Tra

nspo

r t D

epar

tmen

t)

14

16

18

20

7

40

40

60

40

40

80

60

40

40

100

60

60

60

80

8080

80

80

100

RCP

Gas W

orks

TEI LUNG HAU

Sha Tin Treatment Works

CUL

CUL

PipelineWT

TankPipeline

Filter Beds

Filter Beds

CUL

CUL

Filter Beds

WIPApr 2010

WIP Apr 2010

CUL

CUL

CUL

CUL

Nullah

FP FB

FP

RoadCW

FP

Road

F P

FP

CW

FP

Road

FP FP

FP

Ramp

Ramp

Railw

ay Tunne l (Disused)

Railw

ay Tunnel

Road

FP

EW

FB

F

L L

L

LL

L

HH L

LLL

H

L

EH

L

HET

H E

L

ET

H

H

L

L

L

L

L

H

L

L

L

APPENDIX A

Responses from Government Departments on Relevant Information

APPENDIX B

Selected Aerial Photos

APPENDIX C

Material Safety Data Sheet for Chemicals Used in STWTW

Stored/applied chemicals in Chemical House, STWTW

Item Types Detailed Chemicals Description1 Alum Aluminum Sulfate2 Lime Chloride Calcium Hypochlorite3 Lime Lime Powder4 Polymer Magnafloc LT275 Hexafluorosilicate Sodium Silicofluoride

Material Safety Data Sheet

1. PRODUCT AND COMPANY IDENTIFICATION

Product Name Calcium hypochlorite Cat No. C100-250; C100-500 Synonyms Chlorinated Lime; Calcium oxychloride; Hypochlorous acid calcium salt (Granular/Certified) Recommended Use Laboratory chemicals

2. HAZARDS IDENTIFICATION

Target Organs Respiratory system, Eyes, Skin, Gastrointestinal tract (GI) Potential Health Effects Acute Effects Principle Routes of Exposure Eyes Causes burns. Skin Causes burns. May be harmful in contact with skin. Inhalation Causes burns. May be harmful if inhaled. Ingestion Harmful if swallowed. Causes burns. Chronic Effects None known. See Section 11 for additional Toxicological information. Aggravated Medical Conditions No information available.

_____________________________________________________________________________________________

Page 1 / 8

Revision Date 28-May-2010

Oxidizer: Contact with combustible/organic material may cause fire. Causes burns by all exposure routes. Harmful if swallowed. Contact with acids liberates toxic gas. Very toxic to aquatic organisms.

CompanyFisher ScientificOne Reagent LaneFair Lawn, NJ 07410Tel: (201) 796-7100

Emergency Telephone NumberCHEMTREC®, Inside the USA: 800-424-9300CHEMTREC®, Outside the USA: 703-527-3887

DANGER!

Revision Number 1

Emergency Overview

Creation Date 28-May-2010

odor slight chlorineAppearance Off-white Physical State Solid

_____________________________________________________________________________________________

3. COMPOSITION/INFORMATION ON INGREDIENTS

Haz/Non-haz

Component CAS-No Weight %Calcium hypochlorite 7778-54-3 100

4. FIRST AID MEASURES

Eye Contact Rinse immediately with plenty of water, also under the eyelids, for at least 15 minutes.

Immediate medical attention is required. Skin Contact Wash off immediately with plenty of water for at least 15 minutes. Immediate medical attention

is required. Inhalation Move to fresh air. If breathing is difficult, give oxygen. Do not use mouth-to-mouth resuscitation

if victim ingested or inhaled the substance; induce artificial respiration with a respiratory medical device. Immediate medical attention is required.

Ingestion Do not induce vomiting. Call a physician or Poison Control Center immediately. Notes to Physician Treat symptomatically.

5. FIRE-FIGHTING MEASURES

Flash Point Not applicable Method No information available. Autoignition Temperature No information available.Explosion Limits Upper No data available Lower No data available Suitable Extinguishing Media Flooding quantities of water. Use water spray to cool unopened

containers. Unsuitable Extinguishing Media Carbon dioxide (CO2). Dry chemical. Hazardous Combustion Products No information available. Sensitivity to mechanical impact No information available. Sensitivity to static discharge No information available. Specific Hazards Arising from the ChemicalOxidizer: Contact with combustible/organic material may cause fire. Decomposes violently at elevated temperatures. Containers may explode when heated. Thermal decomposition can lead to release of irritating gases and vapors. Protective Equipment and Precautions for FirefightersAs in any fire, wear self-contained breathing apparatus pressure-demand, MSHA/NIOSH (approved or equivalent) and full protective gear.

6. ACCIDENTAL RELEASE MEASURES

_____________________________________________________________________________________________

Page 2 / 8

Revision Date 28-May-2010

Health 3 Flammability 0 Instability 1

Thermo Fisher Scientific - Calcium hypochlorite

Physical hazards OXNFPA

_____________________________________________________________________________________________

6. ACCIDENTAL RELEASE MEASURESPersonal Precautions Use personal protective equipment. Evacuate personnel to safe areas. Keep people away from

and upwind of spill/leak. Ensure adequate ventilation. Avoid dust formation. Do not get in eyes, on skin, or on clothing.

Environmental Precautions Should not be released into the environment. Methods for Containment and Clean Up

Keep combustibles (wood, paper, oil, etc) away from spilled material. Sweep up or vacuum up spillage and collect in suitable container for disposal. Avoid dust formation.

7. HANDLING AND STORAGE

Handling Use only under a chemical fume hood. Wear personal protective equipment. Keep away from

clothing and other combustible materials. Ensure adequate ventilation. Avoid dust formation. Do not breathe dust. Do not get in eyes, on skin, or on clothing.

Storage Keep containers tightly closed in a dry, cool and well-ventilated place. Protect from moisture.

Keep away from direct sunlight. Keep away from heat and sources of ignition. Keep at temperatures below 50°C.

8. EXPOSURE CONTROLS / PERSONAL PROTECTION

Engineering Measures Use only under a chemical fume hood. Ensure adequate ventilation, especially in confined

areas. Ensure that eyewash stations and safety showers are close to the workstation location. Exposure Guidelines This product does not contain any hazardous materials with occupational exposure limits

established by the region specific regulatory bodies. NIOSH IDLH: Immediately Dangerous to Life or Health Personal Protective Equipment Eye/face Protection Wear appropriate protective eyeglasses or chemical safety goggles as described by OSHA's

eye and face protection regulations in 29 CFR 1910.133 or European Standard EN166 Skin and body protection Wear appropriate protective gloves and clothing to prevent skin exposure. Respiratory Protection Follow the OSHA respirator regulations found in 29 CFR 1910.134 or European Standard EN

149. Use a NIOSH/MSHA or European Standard EN 149 approved respirator if exposure limits are exceeded or if irritation or other symptoms are experienced.

9. PHYSICAL AND CHEMICAL PROPERTIES

Physical State SolidAppearance Off-whiteodor slight chlorineOdor Threshold No information available.pH 11.4 Vapor Pressure No information available.Vapor Density No information available.Viscosity No information available.Boiling Point/Range No information available.Melting Point/Range 100°C / 212°FDecomposition temperature No information available.Flash Point Not applicableEvaporation Rate No information available.Specific Gravity 2.350

_____________________________________________________________________________________________

Page 3 / 8

Thermo Fisher Scientific - Calcium hypochlorite Revision Date 28-May-2010

_____________________________________________________________________________________________

9. PHYSICAL AND CHEMICAL PROPERTIESSolubility No information available.log Pow No data availableMolecular Weight 142.98Molecular Formula Ca Cl2 O2

10. STABILITY AND REACTIVITY

Stability Oxidizer: Contact with combustible/organic material may cause fire.

heat sensitive. Moisture sensitive. Conditions to Avoid Incompatible products. Combustible material. Exposure to moist air

or water. Temperatures above 50°C. Incompatible Materials Organic materials, Acids, Amines, Ammonia, Alcohols, Reducing

agents, Metals Hazardous Decomposition Products Hydrogen chloride gas, Chlorine, oxygen Hazardous Polymerization Hazardous polymerization does not occur. Hazardous Reactions . Contact with acids liberates toxic gas. Thermal decomposition.

11. TOXICOLOGICAL INFORMATION

Acute Toxicity

Component Information

Component LD50 Oral LD50 Dermal LC50 InhalationCalcium hypochlorite 850 mg/kg ( Rat ) 2000 mg/kg ( Rabbit ) Not listed

Irritation Causes burns by all exposure routes Toxicologically Synergistic Products

No information available.

Chronic Toxicity Carcinogenicity There are no known carcinogenic chemicals in this product

Sensitization No information available. Mutagenic Effects No information available. Reproductive Effects No information available. Developmental Effects No information available. Teratogenicity No information available.

_____________________________________________________________________________________________

Page 4 / 8


_____________________________________________________________________________________________ Other Adverse Effects The toxicological properties have not been fully investigated.. See actual entry in RTECS for

complete information. Endocrine Disruptor Information No information available

12. ECOLOGICAL INFORMATION

EcotoxicityVery toxic to aquatic organisms. Persistence and Degradability No information available Bioaccumulation/ Accumulation No information available Mobility No information available

13. DISPOSAL CONSIDERATIONS

Waste Disposal Methods Chemical waste generators must determine whether a discarded chemical is classified as a

hazardous waste. Chemical waste generators must also consult local, regional, and national hazardous waste regulations to ensure complete and accurate classification

14. TRANSPORT INFORMATION

DOT UN-No UN1748 Proper Shipping Name CALCIUM HYPOCHLORITE, DRY Hazard Class 5.1 Packing Group II

TDG UN-No UN1748 Proper Shipping Name CALCIUM HYPOCHLORITE, DRY Hazard Class 5.1 Packing Group II

IATA UN-No UN1748 Proper Shipping Name CALCIUM HYPOCHLORITE, DRY Hazard Class 5.1 Packing Group II

IMDG/IMO UN-No UN1748

_____________________________________________________________________________________________

Page 5 / 8

Revision Date 28-May-2010Thermo Fisher Scientific - Calcium hypochlorite

_____________________________________________________________________________________________

14. TRANSPORT INFORMATION Proper Shipping Name CALCIUM HYPOCHLORITE, DRY Hazard Class 5.1 Packing Group II

15. REGULATORY INFORMATION

International Inventories

Component TSCA DSL NDSL EINECS ELINCS NLP PICCS ENCS AICS CHINA KECL Calcium hypochlorite X X - 231-908-

7- X X X X KE-

04564 X

Legend: X - Listed E - Indicates a substance that is the subject of a Section 5(e) Consent order under TSCA. F - Indicates a substance that is the subject of a Section 5(f) Rule under TSCA. N - Indicates a polymeric substance containing no free-radical initiator in its inventory name but is considered to cover the designated polymer made with any free-radical initiator regardless of the amount used. P - Indicates a commenced PMN substance R - Indicates a substance that is the subject of a Section 6 risk management rule under TSCA. S - Indicates a substance that is identified in a proposed or final Significant New Use Rule T - Indicates a substance that is the subject of a Section 4 test rule under TSCA. XU - Indicates a substance exempt from reporting under the Inventory Update Rule, i.e. Partial Updating of the TSCA Inventory Data Base Production and Site Reports (40 CFR 710(B). Y1 - Indicates an exempt polymer that has a number-average molecular weight of 1,000 or greater. Y2 - Indicates an exempt polymer that is a polyester and is made only from reactants included in a specified list of low concern reactants that comprises one of the eligibility criteria for the exemption rule.

U.S. Federal Regulations TSCA 12(b) Not applicable SARA 313Not applicable

SARA 311/312 Hazardous Categorization Acute Health Hazard Yes Chronic Health Hazard No Fire Hazard No Sudden Release of Pressure Hazard No Reactive Hazard Yes Clean Water Act

Component CWA - Hazardous Substances

CWA - Reportable Quantities

CWA - Toxic Pollutants CWA - Priority Pollutants

Calcium hypochlorite X 10 lb - -

Clean Air Act Not applicable

_____________________________________________________________________________________________

Page 6 / 8


_____________________________________________________________________________________________ OSHA Not applicable CERCLA This material, as supplied, contains one or more substances regulated as a hazardous substance under the Comprehensive Environmental Response Compensation and Liability Act (CERCLA) (40 CFR 302)

Component Hazardous Substances RQs CERCLA EHS RQs

Calcium hypochlorite 10 lb -

California Proposition 65 This product does not contain any Proposition 65 chemicals.

State Right-to-Know

Component Massachusetts New Jersey Pennsylvania Illinois Rhode Island Calcium hypochlorite X X X - X

U.S. Department of Transportation Reportable Quantity (RQ): NDOT Marine Pollutant NDOT Severe Marine Pollutant N U.S. Department of Homeland Security This product does not contain any DHS chemicals. Other International Regulations Mexico - Grade No information available Canada This product has been classified in accordance with the hazard criteria of the Controlled Products Regulations (CPR) and the MSDS contains all the information required by the CPR. WHMIS Hazard ClassC Oxidizing materials E Corrosive material

16. OTHER INFORMATION

Prepared By Regulatory Affairs

_____________________________________________________________________________________________

Page 7 / 8


_____________________________________________________________________________________________

16. OTHER INFORMATION Thermo Fisher Scientific

Tel: (412) 490-8929 Creation Date 28-May-2010 Print Date 28-May-2010 Revision Summary "***", and red text indicates revision Disclaimer The information provided on this Safety Data Sheet is correct to the best of our knowledge, information and belief at the date of its publication. The information given is designed only as a guide for safe handling, use, processing, storage, transportation, disposal and release and is not to be considered as a warranty or quality specification. The information relates only to the specific material designated and may not be valid for such material used in combination with any other material or in any process, unless specified in the text.

End of MSDS

_____________________________________________________________________________________________

Page 8 / 8


APPENDIX D

As-built Floor Plan of the Chemical House

yangwne

Rectangle

yangwne

Typewriter

Appendix D

yangwne

Rectangle

yangwne

Callout

Fluoride Pumps

yangwne

Callout

Change as Fluoride Processing Tanks

yangwne

Rectangle

yangwne

Rectangle

yangwne

Rectangle

yangwne

Callout

Chemicals Pumps

yangwne

Arrow

yangwne

Callout

Fluoride Dosing Room

yangwne

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yangwne

Arrow

APPENDIX E

Site Walkover Checklist

Annex C1Site Walkover Checklist

GENERAL SITE DETAILS

SITE OWNER/CLIENT Water Supplies Department

PROPERTY ADDRESS 12, Keng Hau Road

PERSON CONDUCTING THE QUESTIONNAIRE

NAME Eddie Yang, Irene Wong

POSITION Senior Environmental Consultant, Environmental Consultant

AUTHORIZED OWNER/CLIENT REPRESENTATIVE (IF APPLICABLE)

NAME Tam Hin Lee

POSITION I/NTE(PHO)1

TELEPHONE 2684 3121

SITE ACTIVITIES

Briefly describe activities carried out on site, including types of products/chemicals/materials handled.Obtain a flow schematic if possible.

Number of employees: Full-time: 77 (as on 31/8/11)

Part-time: Nil (as on 31/8/11)

Temporary/Seasonal: 42 (as on 31/8/11)

Maximum no. of people on site at any time: 119 (as on 31/8/11)

Typical hours of operation: 24 hours

Number of shifts: 3

Days per week: 7 days

Weeks per year: All days throughout the year

Scheduled plant shut-down: End 2011

Detail the main sources of energy at the site:

Gas Yes /No

Electricity Yes/No

Coal Yes/No

Oil Yes/No

Other Yes /No

SITE DESCRIPTION

This section is intended to gather information on site setting and environmental receptors on, adjacent orclose to the site.

What is the total site area: ~ 10 hectares

What area of the site is covered by buildings (%): ~ 82%

Please list all current and previous owners/occupiers if possible.

Water Supplies Department

Is a site plan available? If yes, please attach. Yes/No

Are there any other parties on site as tenants or sub-tenants? Yes/No

If yes, identify those parties: Ming Hing Waterworks Engineering Co. Ltd.

Describe surrounding land use (residential, industrial, rural, etc.) and identify neighbouring facilitiesand types of industry.

North: North Works of Sha Tin Water Treatment Works; hill; rural residential blocks

South: Hill

East: Railway; Hin Keng Estate

West: Hill


Describe the topography of the area (flat terrain, rolling hills, mountains, by a large body of water,vegetation, etc.).

Flat terrain and surrounded by hills on its south, west and north direction

State the size and location of the nearest residential communities.

About 20 rural residential blocks at approx. 45 to 250m north of the Project Site; Hin Keng

Estate at approx. 140m east of the Project Site

Are there any sensitive habitats nearby, such as nature reserves, parks, wetlands or sites of specialscientific interest?

Lion Rock Country Park at approx. 325m south of the Project Site; Kam Shan Country Park at

approx. 625m northwest of the Project Site.

Questionnaire with Existing/Previous Site Owner or Occupier

Yes/No Notes1. What are the main activities/operations at the above

address?-- Treating raw water from

reservoirs and DongjiangRiver

2. How long have you been occupying the site? -- Since 19643. Were you the first occupant on site? (If yes, what was

the usage of the site prior to occupancy.)No

4. Prior to your occupancy, who occupied the site? -- Rural villagers5. What were the main activities/operations during their

occupancy?-- Residential and farming

6. Have there been any major changes in operations carriedout at the site in the last 10 years?

No Major expansions in 1973, 1976and 1983

7. Have any polluting activities been carried out in thevicinity of the site in the past?

No

8. To the best of your knowledge, has the site ever beenused as a petrol filling station/car service garage?

No

9. Are there any boreholes/wells or natural springs eitheron the site or in the surrounding area?

No

10. Do you have any registered hazardous installations asdefined under relevant ordinances? (If yes, pleaseprovide details.)

Yes Use and storage of Chlorine in 1-tonne drum. Cylinders of helium,nitrogen, argon and synthetic air(Stored outside EIA Study Area;not discussed in the followingsections)

11. Are any chemicals used in your daily operations? (If yes,please provide details.)

Yes Lubricating oil and fuels forpumps and backup generators;lime, alum, polyelectrolyte andfluoride for water treatment;transformer oil; laboratorychemicals and cleansing agents;paints and household cleansingagents

Where do you store these chemicals? -- Dangerous Goods Stores andChemical House

12. Material inventory lists, including quantities and locationsavailable? (If yes, how often are these inventoriesupdated?)

Yes In a ledger system and regularlyupdated (when materials werereceived or after used)

13. Has the facility produced a separate hazardous substanceinventory?

Yes Regularly updated (whenmaterials were received or afterused)

Yes/No Notes14. Have there ever been any incidents or accidents (e.g.

spills, fires, injuries, etc.) involving any of thesematerials? (If yes, please provide details.)

Yes A crane truck overturned on theaccess road to WashwaterRecovery Tanks on 15 March2010. Small amount of dieselwas leaked from the fuel tank ofthe truck on the road and flowninto the surface channel on theside of road

15. Do you have any underground storage tanks? (If yes,please provide details.)

Yes

• How many underground storage tanks do you have onsite?

-- 16 underground chemicalprocessing tanks

• What are the tanks constructed of? -- Concrete• What are the contents of these tanks? -- Lime, alum, polyelectrolyte and

fluoride• Are the pipelines above or below ground? -- Above ground / in pipe trough• If the pipelines are below ground, has any leak and

integrity testing been performed?-- Not applicable

• Have there been any spills associated with these tanks? No16. Are there any disused underground storage tanks? Yes Filled and sealed by concrete17. Do you have regular check for any spillage and

monitoring of chemicals handled? (If yes, please providedetails.)

Yes Monitoring system for Chlorine

18. How are the wastes disposed of? -- Temporarily stored in chemicalwaste storage area and collectedby licensed chemical wastecollector

19. Have you ever received any notices of violation ofenvironmental regulations or received public complaints?(If yes, please provide details.)

Yes A few complaints concerningnoise some years ago

20. Have any spills occurred on site? (If yes, please providedetails.)

Yes Refer to Question No. 14

• When did the spill occur? -- 15 March 2010• What were the substances spilled? -- diesel• What was the quantity of material spilled? -- Small amount• Did you notify the relevant departments of the spill? -- Fire Services Department• What were the actions taken to clean up the spill? -- Collected the leaked diesel and

cleared off by the subcontractor• What were the areas affected? -- Access road to Washwater

Recovery Tanks and nearbysurface channel

21. Do you have any records of major renovation of your siteor re-arrangement of underground utilities, pipework/underground tanks (If yes, please provide details.)

No

22. Have disused underground tanks been removed orotherwise secured (e.g. concrete, sand, etc.)?

Yes There was one disusedunderground diesel storage tankfilled up and sealed by concrete

23. Are there any known contaminations on site? (If yes,please provide details.)

No

24. Has the site ever been remediated? (If yes, pleaseprovide details.)

No


Observations

Yes/No Notes1. Are chemical storage areas provided with secondary

containment (i.e. bund walls and floors)?-- Floors of Dangerous Goods

Stores, Chemical House, andChlorination House are allconcrete paved. Somechemicals are placed onshelves. The tanks in ChemicalHouse are all made of concrete.

2. What are the conditions of the bund walls and floors? -- Intact with no observable stainexcept a small amount of oilleaked from an idle portablegenerator at the Staff QuartersStorage Compound

3. Are any surface water drains located near to drumstorage and unloading areas?

Yes Outside the dangerous goodsstores

4. Are any solid or liquid waste (other than wastewater)generated at the site? (If yes, please providedetails.)

Yes Spent lube oil

5. Is there a storage site for the wastes? Yes Designated chemical wastestorage area and open storageof disused equipments andparts

6. Is there an on-site landfill? No7. Were any stressed vegetation noted on site during

the site reconnaissance? (If yes, please indicatelocation and approximate size.)

No

8. Were any stained surfaces noted on-site during thesite reconnaissance? (If yes, please provide details.)

No

9. Are there any potential off-site sources ofcontamination?

No

10. Does the site have any equipment which mightcontain polychlorinated biphenyls (PCBs)?

Yes The transformer oil as used bythe backup transformerscurrently does not contain PCB

11. Are there any sumps, effluent pits, interceptors orlagoons on site?

Yes The tanks and pits within theEIA study area are primarilyused for raw water treatmentand delivery.

12. Any noticeable odours during site walkover? No13. Are any of the following chemicals used on site:

fuels, lubricating oils, hydraulic fluids, cleaningsolvents, used chemical solutions, acids, anti-corrosive paints, thinners, coal, ash, oily tanks andbilge sludge, metal wastes, wood preservatives andpolyurethane foam?

Yes Fuels, lubricating oils,discarded equipment, chemicalsolutions

APPENDIX F

WSD’s Confirmation Letter Concerning the SI Works Schedule

Design and Construction Contamination Assessment Plan ...

Documents

Transcript of Design and Construction Contamination Assessment Plan ...