Executive Summary

Introduction

A1. The Project, Design, Build and Operate First Stage of Tseung Kwan O Desalination Plant (TKODP), is a Designated Project under the Environmental Impact Assessment Ordinance (Cap. 499) (EIAO) and is currently governed by a Further Environmental Permit (EP No. FEP - 01/503/2015/A) for the construction and operation of the Contract.

A2. In accordance with the Environmental Monitoring and Audit (EM&A) Manual for the Contract, EM&A works for marine water quality, noise, waste management and ecology should be carried out by Environmental Team (ET), Acuity Sustainability Consulting Limited (ASCL), during the construction phase of the Contract.

A3. This is the 46th Monthly EM&A Report, prepared by ASCL, for the Contract summarizing the monitoring results and audit findings of the EM&A programme at and around Tseung Kwan O Area 137 (TKO 137) during the reporting period from 1 December to 31 December 2023.

A4. The EM&A programme for this contract has covered environmental monitoring on construction noise level at selected NSRs and Contractor’s environmental performance auditing in the aspects of construction dust, construction noise, water quality, waste management, Landscape and Visual and Ecology.

Summary of Main Works Undertaken & Key Mitigation Measures Implemented

A5. Key activities carried out in this reporting period for the Contract included the followings:

Administration Building

- Carrying out the floor tiles works at G/F

- External wall painting works

- Construction of block work for pipe duct

- Installation of building services, cable laying, electrical switchboard, testing and commissioning

Chemical building

- Installation of leakage collection pit cover

- Underground utility construction work

- Landscape work at roof

- Defect rectification

Main Electrical & Central Chiller Plant Building

- Installation of chillers, building services, electrical switchboard and cable laying

- Installation of Roof Tile for Fuel Tank Room

ActiDAFF

- Underground utility construction work

- Installation of access opening cover

- Construction of staircase no 2

- Installation of mechanical equipment, piping system, installation of building services, electrical switchboards and cable laying, fiber-reinforced plastic cover Installation

Product Water Storage Tank Building

- Installation of Cat Ladders in Water Tank A

- Sealing slab opening in water Tank A

- Re-construction of Wall PW8 in Water Tank A

- Installation of metal cladding, building services, cable laying, mechanical equipment, steel pipe

- Underground utility construction

OSCG Building

- Protective Coating for dangerous goods Rooms

- Placing Soil Mix at Roof

- Installation of Metal Cladding (at East Side) and Roller Shutters and Window

- Underground utility construction work

- Installation of building services, mechanical equipment and cable laying, testing and commissioning

Reverse Osmosis Building

- Installation of building services, electrical switchboard, cable laying, Installation of mechanical equipment, steel pipe, Glass Reinforced Plastic pipe, raised floor, testing and commissioning

- Installation of metal cladding, handrailing, roller shutters, glass canopy and

glass house

- Underground utility construction work

- Construction of Reinforced Concrete External Wall for Male Toilet

Post Treatment Building

- Installation of building services, Installation of mechanical equipment and piping system, Pressure Test

- Underground utility construction work

- Installation of Cat Ladders in Water Tanks

- Installation of Metal Cladding

- Placing Soil Mix at Roof

Inspection corridor

- Installation of building services, Lift installation

- Construction of roof tiling works and staircases no. 2

- Installation of Movement Joints and glass window

CO2 Tanks

- Installation of pipes and electrical wiring, testing and commissioning Combined Shaft and Pump room

- Finishing, Grating; window; louvre installation Other

- Watermain works at CLP 132 kV Substation

- Staircases construction; Steel Bridge assembly and installation at elevated walkway

- Road Construction, Footpath Construction, Landscape Construction, Irrigation System Construction, Water Pressure Test for Fire Services and Plumbing System in Zone A, B, C

- Structure Construction, steel fence erection of Wave Deflector Wall at seawall area

A6. The major environmental impacts brought by the above construction works include:

- Construction dust and noise generation from construction works and excavation works;

- Waste generation from the construction activities

A7. The key environmental mitigation measures implemented for the Contract in this reporting period associated with the above construction works include:

- Dust suppression by regular wetting and water spraying for construction works;

- Reduction of noise from equipment and machinery on-site and regular inspection to machinery and plants/vehicles on-site to ensure proper functioning;

- Deployment of silt curtain at the marine areas; and

- Sorting and storage of general refuse and construction waste;

Summary of exceedance & investigation & follow-up

A8. No noise monitoring was conducted during the reporting period since there are no Contract -related construction activities undertaken within a radius of 300m from the monitoring locations. No exceedance of the action Level was recorded during the reporting period.

A9. The construction phase marine water quality programme was ceased from 1 September 2023 due to the completion of marine-related construction works.

A10. The EM&A works for commissioning phase water quality were conducted during the reporting period in accordance with the EM&A Manual. Thirty-five (35) of the commissioning phase water quality monitoring results of SS obtained had exceeded the Action Level. Twenty-seven (27) of the commissioning phase water quality monitoring results of SS obtained during the reporting period had exceeded the Limit Level. After investigation, all exceedances were concluded unrelated to the Project.

A11. Seven (7) of dechlorinated effluent sample were taken in contact tank/ product water tank on 3 December 2023. No TRC exceedance of action or limit levels was obtained during the discharge of dechlorinated effluent.

A12. Pre-operation phase coral monitoring works was conducted on 28 December 2023. All tagged coral colonies showed good health condition during the December 2023 monitoring survey. There was no increased level of mortality, bleaching and sediment in other tagged coral colonies when compared with the baseline results. There is no AL/LL exceedance during the monitoring period.

A13. In this reporting period, 72 times of landfill gas monitoring were conducted at TKO Area 137 (Ch1+340 - Ch1+600). No action or limit level exceedance was recorded during the reporting period.

A14. Joint site inspections of the construction work by ET and IEC were carried out on 5, 12, 19, 27 December 2023 to audit the mitigation measures implementation status. Reminders were recorded in the site inspection checklists and provided to the contractors together with the appropriate follow-up actions where necessary.

Complaint Handling and Prosecution

A15. No environmental complaint, notification of summons and prosecution was received in the reporting period.

Reporting Change

A16. There was no change to be reported that may affect the on-going EM&A programme.

Summary of Upcoming Key Issues and Key Mitigation Measures

A17. Key activities anticipated in the next reporting period for the Contract will include the followings:

Administration Building

- Landscaping works on roof of building.

- External wall aluminum features installation

- Finishing works for doghouse.

- Installation of building services, cable laying, electrical switchboard, Pressure Test, electrical switchboard, testing and commissioning

Chemical building

- Landscape work at roof

- Construction of hose reel cabinet.

- Defect rectification

Main Electrical & Central Chiller Plant Building

- Installation of Roof Tile for Fuel Tank Room

- Minor Installation of building services, electrical switchboard, cable laying, pressure test

ActiDAFF

- Underground utility construction work

- Installation of access opening covers for filtered water tank

- Carrying out finishing works for staircase no. 3

- Minor Installation of mechanical equipment, piping system, building services, electrical switchboards and cable laying, fiber-reinforced plastic

cover Installation

Product Water Storage Tank Building

- Water Test in Tank A

- Waterproofing work at Roof Slab on Tank A

- Tank A water test and defect rectification

- Installation of building services, cable laying, Installation of mechanical equipment, steel pipe, Pressure Test

OSCG Building

- Installation of Railing on Brine Maker Tank

- Protective Coating for dangerous goods Rooms

- Installation of building services, mechanical equipment and cable laying, Lightning Installation, testing and commissioning

Reverse Osmosis Building

- Installation of Handrailings

- Installation of Glass House

- Installation of building services, electrical switchboard, cable laying, Photovoltaic Panel. Minor Installation of mechanical equipment and raised floor, testing and commissioning

- Underground utility construction work

Post Treatment Building

- Installation of Cat Ladders in Water Tanks

- Placing Soil Mix at Roof

- Curb Construction for Rescue Opening at Water Tanks

- Installation of building services, mechanical equipment and piping system, Pressure Test

Inspection corridor

- Construction of roof tiling works

- Installation of steel balustrade at roof

- Installation of Movement Joints

- Installation of glass window

- Installation of building services, Lift Installation

CO2 Tanks

- Tank surface cleaning, testing and commissioning Combined Shaft and Pump room

- Internal finishing, defect rectification Guard House

- Installation of Building Services

- Workshop construction work

Other

- Glass Roof and Glass Canopy installation at elevated walkway

- Security Fence footing construction work

- Manhole 5 Glass Reinforced Plastic Installation work

- Underground utility rectification work

- Road Construction

- Traffic signage work

- Footpath Construction

- Landscape Construction

- Landscape planting work

- Irrigation System Construction

- Slope work - Shotcreteing; Rock anchor installation, Rock break

- Water Pressure Test for Fire Services and Plumbing System

- Open Channel and Wave deflector Wall

- Traffic signage work

A18. The major environmental impacts brought by the above construction works will include:

- Construction dust and noise generation from excavation and construction works;

- Waste generation from construction activities

A19. The key environmental mitigation measures for the Contract in the coming reporting period associated with the above construction works will include:

- Reduction of noise from equipment and machinery on-site;

- Dust suppression by regular wetting and water spraying for construction works and at main haul road;

- Sorting and storage of general refuse and construction waste; and

- Deployment of silt curtain at the marine areas.

1. Basic Contract Information

Background

1.1. The Acciona Agua, S.A. Trading, Jardine Engineering Corporation, Limited and China State Construction Engineering (Hong Kong) Limited as AJC Joint Venture (AJCJV) is contracted to carry out the Design, Build and Operate First Stage of Tseung Kwan O Desalination Plant (DPTKO) under Contract No. 13/WSD/17 (the Contract).

1.2. Acuity Sustainability Consulting Limited (ASCL) is commissioned by AJCJV to undertake the Environmental Team (ET) services as required and/or implied, both explicitly and implicitly, in the Environmental Permit (EP), Environmental Impact Assessment Report (EIA Report) (Register No. AEIAR-192/2015) and Environmental Monitoring and Audit Manual (EM&A Manual) for the Contract; and to carry out the Environmental Monitoring and Audit (EM&A) programme in fulfillment of the EIA Report’s EM&A requirements and Contract No. 13/WSD/17 Specification requirements.

1.3. Pursuant to the Environmental Impact Assessment Ordinance (EIAO), the Director of Environmental Protection granted the Environmental Permit (No. EP-01/503/2015) and Variation of Environmental Permit (No. EP-01/503/2015/A) to Water Supplies Department (WSD); and granted the Further Environmental Permit (No. FEP- 01/503/2015/A) to AJCJV for the Contract.

The Reporting Scope

1.4. This is the 46th Monthly EM&A Report for the Contract which summarizes the key findings of the EM&A programme during the reporting period from 1 December to 31 December 2023.

Contract Organization

1.5. The Contract Organization structure for Construction Phase is presented in Figure 1.1.

Figure 1.1 Contract Organization Chart

1.6. Contact details of the key personnel are presented in Table 1.1 below:

Table 1.1 Contact Details of Key Personnel

Party	Position	Name	Telephone no.
Contract Proponent (Water Supplies Department)	SE/CM2	Milton Law	2634-3573
Supervising Officer (Binnies Hong Kong Limited)	Project Manager	Christina Ko	2608-7302
Supervising Officer (Binnies Hong Kong Limited)	Chief Resident Engineer	Roger Wu	6343-1002
The Jardine Engineering Corporation, Limited, China State Construction Engineering (Hong Kong) Limited and Acciona Agua, S.A. Trading	Project Manager	Stephen Yeung	2807-4665
	Environmental Monitoring Manager	Brian Kam	9456-9541
	Environmental Monitoring Manager	Joy Chan	6468-1782
Acuity Sustainability Consulting Limited	Environmental Team Leader	Jacky Leung	2698-6833
ANewR Consulting Limited	Independent Environmental Checker (IEC)	Mr. CHAN Yi Chun, Alex	2618-2831

Summary of Construction Works

1.7. Details of the major construction activities undertaken in this reporting period are shown below. The master programme is presented in Appendix A.

1.8. Key activities carried out in this reporting period for the Contract included the followings:

Administration Building

- Carrying out the floor tiles works at G/F

- External wall painting works

- Construction of block work for pipe duct

- Installation of building services, cable laying, electrical switchboard, testing and commissioning

Chemical building

- Installation of leakage collection pit cover

- Underground utility construction work

- Landscape work at roof

- Defect rectification

Main Electrical & Central Chiller Plant Building

- Installation of chillers, building services, electrical switchboard and cable laying

- Installation of Roof Tile for Fuel Tank Room

ActiDAFF

- Underground utility construction work

- Installation of access opening cover

- Construction of staircase no 2

- Installation of mechanical equipment, piping system, installation of building services, electrical switchboards and cable laying, fiber-reinforced plastic cover Installation

Product Water Storage Tank Building

- Installation of Cat Ladders in Water Tank A

- Sealing slab opening in water Tank A

- Re-construction of Wall PW8 in Water Tank A

- Installation of metal cladding, building services, cable laying, mechanical equipment, steel pipe

- Underground utility construction

OSCG Building

- Protective Coating for dangerous goods Rooms

- Placing Soil Mix at Roof

- Installation of Metal Cladding (at East Side) and Roller Shutters and Window

- Underground utility construction work

- Installation of building services, mechanical equipment and cable laying, testing and commissioning

Reverse Osmosis Building

- Installation of building services, electrical switchboard, cable laying, Installation of mechanical equipment, steel pipe, Glass Reinforced Plastic pipe, raised floor, testing and commissioning

- Installation of metal cladding, handrailing, roller shutters, glass canopy and glass house

- Underground utility construction work

- Construction of reinforced concrete External Wall for Male Toilet

Post Treatment Building

- Installation of building services, Installation of mechanical equipment and piping system, Pressure Test

- Underground utility construction work

- Installation of Cat Ladders in Water Tanks

- Installation of Metal Cladding

- Placing Soil Mix at Roof

Inspection corridor

- Installation of building services, Lift installation

- Construction of roof tiling works and staircases no. 2

- Installation of Movement Joints and glass window

CO2 Tanks

- Installation of pipes and electrical wiring, testing and commissioning Combined Shaft and Pump room

- Finishing, Grating; window; louvre installation Other

- Watermain works at CLP 132 kV Substation

- Staircases construction; Steel Bridge assembly and installation at elevated walkway

- Road Construction, Footpath Construction, Landscape Construction, Irrigation System Construction, Water Pressure Test for Fire Services and Plumbing System in Zone A, B, C

- Structure Construction, steel fence erection of Wave Deflector Wall at seawall area

1.9. A summary of the valid permits, licences, and/or notifications on environmental protection for this Contract is presented in Table 1.2.

Table 1.2 Summary of the Status of Valid Environmental Licence, Notification, Permit and Documentations

Permit/ Licences	Valid Period		Status	Remark
	From	To
Environmental Permit
EP-503/2015/A	Throughout the Contract		Valid	-
FEP - 01/503/2015/A	Throughout the Contract		Valid	-
Notification of Construction Works under the Air Pollution Control (Construction Dust) Regulation (Form NA)
451539	Throughout the Contract		Valid	-
Billing Account for Disposal of Construction Waste
7036276	Throughout the Contract		Valid	-
Chemical Waste Producer Registration
5213-839-A2987-01	Throughout the Contract		Valid	-
Wastewater Discharge Licence (Land and Marine works)
WT00035775-2020	23/08/2021	31/07/2025	Valid	-
WT00044188-2023	16/06/2023	30/06/2028	Valid	For Plant T&C and operation

Permit/ Licences	Valid Period		Status	Remark
Permit/ Licences	From	To	Status	Remark
Construction Noise Permit
GW-RE0640-23	22/06/2023	21/12/2023	Valid	Expired in the reporting month
GW-RE1514-23	22/12/2023	21/06/2024	Valid	-

1.10. The status for all environmental aspects is presented in Table 1.3.

Table 1.3 Summary of Status for Key Environmental Aspects under the EM&A Manual

Parameters	Status
Water Quality
Baseline Monitoring under EM&A Manual	The baseline water quality monitoring was conducted between 12 May 2020 to 6 Jun 2020.
Construction Phase Impact Monitoring	Ceased from 1 September 2023
Commissioning Phase Marine Impact Monitoring	On-going
Impact Monitoring of Effluent Discharge from Main Disinfection	On-going
Noise
Baseline Monitoring	The baseline noise monitoring result has been reported in Baseline Monitoring Report and submitted to EPD under EP Condition 3.4
Impact Monitoring	Completed
Waste Management
Mitigation Measures in Waste Management Plan	On-going
Landfill Gas
Regular Monitoring when construction works are within the 250 m Consultation Zone	On-going
Ecology (Coral)
Pre-operation phase Regular Coral Monitoring (Monthly)	On-going

2. Noise

Monitoring Requirements

2.1. To ensure no adverse noise impact, noise monitoring is recommended to be carried out within 300m radius from the nearby noise sensitive receivers (NSRs), during construction phase. The NSRs selected as monitoring station are (i) NSR4 - Creative Secondary School, (ii) NSR24 - PLK Laws Foundation College, and (iii) NSR31 - School of Continuing and Professional Studies - CUHK respectively.

2.2. Construction noise level were measured in terms of the A-weighted equivalent continuous sound pressure level (LAeq). Leq 30min was used as the monitoring parameter for the time period between 0700 and 1900 on normal weekdays. Construction works would follow stipulations of the valid Construction Noise Permits if works had to be conducted during restricted hours or public holidays. Table 2.1 summarizes the monitoring parameters, frequency, and duration of the impact noise monitoring.

Table 2.1 Noise Monitoring Parameters, Time, Frequency and Duration

Time

Duration

Interval

Parameters

Daytime: 0700-1900

Day time: 0700-1900

(during normal weekdays)

Continuously in

Leq 5min/Leq 30min (average of 6 consecutive Leq 5min)

Leq 30min

L10 30min & L90 30min

Monitoring Locations

2.3. The monitoring locations were normally made at a point 1m from the exterior of the NSRs building façade and be at a position 1.2m above the ground. A correction of +3dB(A) should be made to the free-field measurements.

2.4. According to the environmental findings detailed in the EIA report and Baseline Monitoring Report, the designated locations for the construction noise monitoring are listed in Table 2.2 below.

Table 2.2 Noise Sensitive Receivers

NSR ID	Noise Sensitive Receivers	Monitoring Location	Position
NSR 4	Creative Secondary School	Roof Floor	1 m from facade
NSR 24	PLK Laws Foundation College	Pedestrian Road on Ground Floor	Free-field
NSR 31	School of Continuing and Professional Studies - CUHK	Roof Floor	1 m from facade

2.5. Three noise monitoring locations for impact monitoring at the nearby sensitive receivers are shown in Figure 2.1-2.3.

Figure 2.3 NSR31 School of Continuing and Professional Studies - CUHK

Impact Monitoring Methodology

2.6. Integrated sound level meter will be used for the noise monitoring. The meter will be in compliance with the International Electrotechnical Commission Publications 651: 1979 (Type 1) and 804: 1985 (Type 1) specifications. Immediately prior to and following each noise measurement the accuracy of the sound level meter will be checked using an acoustic calibrator generating a known sound pressure level at a known frequency. Measurements will be accepted as valid only if the calibration levels before and after the noise measurements agree to within 1.0 dB(A).

2.7. Noise measurements were not made in the presence of fog, rain, wind with a steady speed exceeding 5 m/s or wind with gusts exceeding 10 m/s. The wind speed shall be checked with a portable wind speed meter capable of measuring the wind speed in m/s.

Action and Limit Levels

2.8. The Action/Limit Levels are in line with the criteria of Practice Note for Professional Persons (ProPECC PN 2/93) “Noise from Construction Activities - Non-statutory Controls” and Technical Memorandum on Environmental Impact Assessment Process issued by HKSAR Environmental Protection Department [“EPD”] under the Environmental Impact Assessment Ordinance, Cap 499, S.16 are presented in Table 2.3.

Table 2.3 Action and Limit Levels for Noise per EM&A Manual

Time Period

Action

Limit (dB(A))

0700-1900 on normal weekdays

When one documented complaint is received from any one of the noise sensitive receivers

- 70 dB(A) for school and

- 65 dB(A) during examination period

Note: Limits specified in the GW-TM and IND-TM for construction and operation noise, respectively.

2.9. If exceedances were found during noise monitoring, the actions in accordance with the Event and Action Plan shall be carried out according to Appendix E.

Monitoring Results and Observations

2.10. Referring to EM&A Manual Section 4.1.2, the impact noise monitoring should be carried out when there are Contract-related construction activities undertaken within a radius of 300m from the monitoring stations. No monitoring station was located within a radius of 300m of the Contract site as shown in Figure 2.4, no impact noise monitoring was conducted in the reporting period.

Figure 2.4 Site Layout Plan with Noise Sensitive Receivers and Desalination Plant

3. Water Quality

3.1. In accordance with the recommendations of the EIA, water quality monitoring is required during dredging for the submarine pipelines and, during operation phase. The following Section provides details of the water quality monitoring to be undertaken by the Environmental Team (ET) to verify the distance of sediment and brine plume dispersion and to identify whether the potential exists for any indirect impacts to occur to ecological sensitive receivers.

3.2. The water quality monitoring programme was be carried out to allow any deteriorating water quality to be readily detected and timely action taken to rectify the situation.

3.3. Water quality monitoring for the Contract can be divided into the following stages:

- Dredging activities during construction phase;

- Discharge of effluent from main disinfection during construction phase; and

- Operation activities during commissioning phase

Water Quality Parameters

3.4. The parameters that have been selected for measurement in situ and in the laboratory are those that were either determined in the EIA to be those with the most potential to be affected by the construction works or are a standard check on water quality conditions. Parameters to be measured in the impact monitoring are listed in Table 3.1.

Table 3.1 Parameters measured in the Impact Marine Water Quality Monitoring

Parameters	Unit	Abbreviation
In-situ measurements
Dissolved oxygen	mg/L	DO
Temperature	oC	-
pH	-	-
Turbidity	NTU	-
Salinity	0/00	-
Total Residual Chlorine NOTE1	mg/L	TRC
Laboratory measurements
Suspended Solids	mg/L	SS
Iron-Soluble	mg/L	Fe
Anti-scalant as Reactive Phosphorus	mg/L	PO4 as P-

NOTE 1: Monitoring of Total Residual Chlorine will be conducted when cleaning and sterilization of the new freshwater main is carried out.

3.5. In addition to the water quality parameters, other relevant data were also being measured and recorded in Water Quality Monitoring Logs, including the location of the sampling stations, water depth, time, weather conditions, sea conditions, tidal stage, current direction and velocity, special phenomena and work activities undertaken around the monitoring and works area that may influence the monitoring results.

Monitoring Equipment

3.6. For water quality monitoring, the following equipment were used:

Dissolved Oxygen and Temperature Measuring Equipment - The instrument was a portable, weatherproof dissolved oxygen measuring instrument complete with cable, sensor, comprehensive operation manuals, and was operable from a DC power source. It was capable of measuring: dissolved oxygen levels in the range of 0 - 20 mg/L and 0 - 200% saturation; and a temperature of 0 - 45 degrees Celsius. It has a membrane electrode with automatic temperature compensation complete with a cable of not less than 35 m in length. Sufficient stocks of spare electrodes and cables were available for replacement where necessary (e.g. YSI model 59 DO meter, YSI 5739 probe, YSI 5795A submersible stirrer with reel and cable or an approved similar instrument).

Turbidity Measurement Equipment - The instrument was a portable, weatherproof turbidity-measuring unit complete with cable, sensor and comprehensive operation manuals. The equipment was operated from a DC power source, it has a photoelectric sensor capable of measuring turbidity between 0 - 1000 NTU and complete with a cable with at least 35 m in length (for example Hach 2100P or an approved similar instrument).

Salinity Measurement Instrument - A portable salinometer capable of measuring salinity in the range of 0 - 40 ppt was provided for measuring salinity of the water at each monitoring location.

Water Depth Gauge - A portable, battery-operated echo sounder (for example Seafarer 700 or a similar approved instrument) was used for the determination of water depth at each designated monitoring station. This unit will preferably be affixed to the bottom of the work boat if the same vessel is to be used throughout the monitoring programme. The echo sounder was suitably calibrated.

Positioning Device - A Global Positioning System (GPS) was used during monitoring to allow accurate recording of the position of the monitoring vessel before taking measurements. The Differential GPS, or equivalent instrument, was suitably calibrated at appropriate checkpoint (e.g. Quarry Bay Survey Nail) to verify that the monitoring station is at the correct position before the water quality monitoring commence.

Water Sampling Equipment - A water sampler, consisting of a PVC or glass cylinder of not less than two litres, which can be effectively sealed with cups at both ends, was used. The water sampler has a positive latching system to keep it open and prevent premature closure until released by a messenger when the sampler is at the selected water depth.

Total Residual Chlorine -Total residual chlorine (TRC) shall be measured in-situ using approved test kit.

Sampling / Testing Protocols

3.7. All in situ monitoring instruments were checked, calibrated, and certified by a laboratory accredited under HOKLAS or any other international accreditation scheme before use, and subsequently re-calibrated at monthly intervals throughout the stages of the water quality monitoring. Responses of sensors and electrodes were checked with certified standard solutions before each use.

3.8. On-site calibration of field equipment was following the “Guide to On-Site Test Methods for the Analysis of Waters”, BS 1427: 2009. Sufficient stocks of spare parts were maintained for replacements when necessary. Backup monitoring equipment was made available so that monitoring can proceed uninterrupted even when equipment is under maintenance, calibration etc.

Laboratory Measurement and Analysis

3.9. Sufficient volume of each water sample was collected for carrying out the laboratory analyses. Using chain of custody forms, collected water samples were transferred to a HOKLAS accredited laboratory (Acumen Laboratory and Testing Limit - HOKLAS 241) for immediate processing. The determination work was start within the next working day after collection of the water samples. Analytical methodology and sample preservation of other parameters were based on the latest edition of Standard Methods for the Examination of Waste and Wastewater published by APHA, AWWA and WPCF and methods by USEPA, or suitable method in accordance with requirements of HOKLAS or another internationally accredited scheme. The QA/QC details were in accordance with the requirements of HOKLAS or another internationally accredited scheme.

3.10. Parameters for laboratory measurements, standard methods and detection limits are presented in Table 3.2.

Table 3.2 Laboratory measurements, standard methods, and corresponding detection limits of marine water quality monitoring

Parameters	Standard Methods	Detection Limit	Reporting Limit	Precision
Dissolved oxygen	Instrumental, CTD	0.1	-	+-25%
Temperature	Instrumental, CTD	0.1	-	+-25%
pH	Instrumental, CTD	0.1	-	+-25%
Turbidity	Instrumental, CTD	0.1	-	+-25%
Salinity	Instrumental, CTD	0.1	-	+-25%
Suspended Solids	APHA 23rd Ed 2540D	1.0	2.5	+-17%
Iron	APHA 3111 B	0.2	-	+-25%
Total residual chlorine	HACH DR300 Test- kit	Lowest limit = 0.01mg/L; Upper limit = 8 mg/L	-	+-25%
Total residual chlorine	Lovibond MD200	Lowest limit = 0.01mg/L; Upper limit = 6 mg/L	-	+-25%

Monitoring Location

Construction Phase

3.11. The Impact water quality monitoring was ceased from 1 September 2023 due to the completion of marine-related construction works.

Commissioning Phase

3.12. The commissioning phase impact water quality monitoring locations are in accordance with the EM&A Manual and detailed in Table 3.3 below. A schedule for water quality monitoring was prepared by the ET and submitted to IEC and EPD prior to the commencement of the monitoring.

Table 3.3 Location of Impact Water Quality Monitoring Stations

Station	Easting	Northing	Description
CE	843550	815243	Upstream control station at ebb tide
CF	846843	810193	Upstream control station at flood tide
WSR1	846864	812014	Ecological sensitive receiver at Tung Lung Chau
WSR2	847645	812993	Fisheries sensitive receiver at Tung Lung Chau
WSR3	848023	813262	Ecological sensitive receiver at Tung Lung Chau
WSR4	847886	814154	Ecological sensitive receiver at Tai Miu Wan
WSR16	845039	815287	Ecological sensitive receiver at Fat Tong Chau
WSR33	847159	814488	Ecological sensitive receiver at Tai Miu Wan
WSR36	846878	814081	Ecological sensitive receiver at Kwun Tsai
WSR37	846655	813810	Ecological sensitive receiver at Tit Cham Chau
NF1	846542	813614	Edge of Mixing zone, ~ 200m west of outfall diffuser
NF2	846942	813614	Edge of Mixing zone, ~ 200m east of outfall diffuser
NF3	846742	813414	Edge of Mixing zone, ~ 200m south of outfall diffuser

3.13. WSR1 to WSR37 were identified in accordance with Annex 14 of the EIAO-TM as well as Clause 3.4.4.2 of the Environmental Impact Assessment Study Brief for Desalination Plant at Tseung Kwan O (No. ESB-266/2013). WSR1 to WSR3 are sited near the Tung Lung Chau Fish Culture Zone; WSR16 and WSR36 are sited near the coral assemblages along the coastlines of Fat Tong Chau and Kwun Tsai respectively; WSR 4 and WSR33 are sited near the Coastal Protection Area and coral assemblages in waters of Tai Miu Wan; WSR37 is sited near the fisheries resource including spawning and nursery grounds at the coastal water of Tit Cham Chau. NF1 to NF3 are the Edge of mixing zone.

Figure 3.1 Impact water quality monitoring locations under EM&A Manual Disinfection

3.14. Effluent of disinfection from desalination plant shall be collected at a suitable location after all treatment process before discharge. The sampling location should be agreed with WSD and EPD, and should fulfil the following requirements:

- Effluent collected at the sampling location is representative to the effluent discharged at the outfall diffuser.

- Sampling works at the sampling location would not interfere with the desalination plant operation.

- Sampling works at the sampling location would not induce safety hazard (e.g. staff sampling effluent drops into the culvert)

3.15. According to the approved Flushing and Disinfection Procedure and Supplementary of the Disinfection Procedure for Desalination Plant at Tseung Kwan O, the sampling point of the dechlorinated effluent was located at Contact tank/Product Water Tank (PWT) and T1GKC01AA502/manhole 18. The approved sampling location was shown in Table 3.4, Figure 3.2 and Figure 3.3 below.

Table 3.4 Sampling location of dechlorinated effluent

System/Loop

Discharge

location

Sampling Location

Contact tank/

Product Water Tank (PWT)

Culvert

Contact tank/PWT

Connection to dist. network

Manhole 18 in

connection point

Sampling point

T1GKC01AA502/manhole 18

Sampling Frequency

Commissioning Phase

3.16. Impact water quality monitoring were carried out three days per week during the commissioning phase. Monitoring at each station was undertaken once per day. The interval between two sets of monitoring was not less than 36 hours. The monitoring frequency would be increased in the case of exceedances of Action/Limit Levels if considered necessary by ET. Monitoring frequency would be maintained as far as practicable.

Disinfection

3.17. For the discharge of dechlorinated effluent used after main sterilization, in-situ testing of total residual chlorine should be conducted every 1 hour (not less than) at the discharge point(s) when dechlorinated effluent is being discharged.

Sampling Depths & Replication

3.18. During impact water quality monitoring, each station was sampled, and measurements/ water samples were taken at three depths, 1 m below the sea surface, mid-depth, and 1 m above the seabed. For in situ measurements, duplicate readings were made at each water depth at each station. Duplicate water samples were collected at each water depth at each station.

Action and Limit Levels

Commissioning Phase

3.19. The Action and Limit Levels have been set based on the derivation criteria specified in the EM&A Manual. The Action/Limit Levels have been derived and are presented in Table 3.6.

Disinfection

3.20. The Action and Limit Levels have been set in accordance with the approved EM&A Manual and presented in Table 3.5. For the TRC, the discharge should be suspended if the TRC level of the dechlorinated effluent exceeds the 0.1 mg/L. Chlorinated water should be fully neutralized before discharge. Discharge of the water will be done once it is ensured that the chlorine has been neutralized and it is below the discharge limit.

Table 3.5 Derived Action and Limit Levels for Water Quality

Parameters	Action	Limit
Commissioning Phase Impact Monitoring
DO in mg/L	Surface and Middle 7.30 mg L-1 Bottom 7.31 mg L-1 Tung Lung Chau Fish Culture Zone 5.1 mgL-1 or level at control station (Whichever the lower)	Surface and Middle 4 mg L-1 Bottom 2 mg L-1 Tung Lung Chau Fish Culture Zone 5.0 mgL-1 or level at control station (Whichever the lower)
SS in mg/L (Depth- averaged)	5.00 mg L-1 or 20% exceedance of value at any impact station compared with corresponding data from control station	6.00 mg L-1 or 30% exceedance of value at any impact station compared with corresponding data from control station
Turbidity in NTU (Depth- averaged)	2.41 NTU or 20% exceedance of value at any impact station compared with corresponding data from control station	2.84 NTU or 30% exceedance of value at any impact station compared with corresponding data from control station
Salinity in PSU (Depth- averaged)	34.25 PSU or 9% exceedance of value at any impact station compared with corresponding data from control station	34.56 PSU or 10% exceedance of value at any impact station compared with corresponding data from control station
Iron in mg/L (Depth- averaged)	0.3 mg/L	0.3 mg/L
Total residual chlorine in mg/L

Rev.	Description of Modification	Date
1.	First Issue for Comments	17/01/2024
2.	Revised According to the Comments	25/01/2024
3	Revised According to the Comments	25/01/2024
4	Revised based on the reporting issue	07/02/2024
5	Revised the Coral Monitoring Information	22/03/2024
6	Revised the Coral Monitoring Information	27/03/2024

Parameters	Status
Ecology (Landscape)
Pre-operation phase Landscape and Visual Site Inspection	On-going
Environmental Audit
Site Inspection covering Measures of Air Quality, Noise Impact, Water Quality, Waste, Ecological Quality, Fisheries, Landscape and Visual	On-going