Lam Environmental Services Limited

19/F, Remex Centre, 42 Wong Chuk Hang Road, Hong Kong


 

Revision History

Rev.

Description of Modification

Date

1.

First Issue

11/11/2024

2.

Second Issue

14/11/2024

3.

Third Issue

18/11/2024

 

 

 

 

 


CONTENTS

Executive Summary............................................................................................................................................................ 1

1.          Basic Contract Information............................................................................................................................... 3

2.          Water Quality.......................................................................................................................................................... 8

3.          Waste....................................................................................................................................................................... 30

4.          Landfill Gas Monitoring................................................................................................................................... 31

5.          Landscape.............................................................................................................................................................. 35

6.          Ecology (Coral Monitoring)............................................................................................................................ 36

7.          Ecology (Fishery Monitoring)....................................................................................................................... 38

8.          Summary of Exceedance, Complaints, Notification of Summons and Prosecutions.............. 41

9.          EM&A Site Inspection....................................................................................................................................... 43

10.      Future Key Issues............................................................................................................................................... 44

11.      Conclusions and Recommendations.......................................................................................................... 45

 

 

Appendix A

Overview of Desalination Plant in Tseung Kwan O

Appendix B

Summary of Implementation Status of Environmental Mitigation

Appendix C

Impact Monitoring Schedule

Appendix D

Event/Action Plan

Appendix E

Water Quality Monitoring Equipment and Landfill Gas Equipment Calibration Certificate

Appendix F

Water Quality Monitoring Data and Landfill Gas Monitoring Data

Appendix G

Waste Flow Table

Appendix H

Ecology (Coral & Fishery) Survey Report

Appendix I

Site Inspection Proforma

Appendix J

Complaint Log

Appendix K

Exceedance Report


 

 

 

 

 

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/B) for the operation phase 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, waste management and ecology should be carried out by Environmental Team (ET), Aurecon Hong Kong Limited (Aurecon), during the Tseung Kwan O Desalination Plant.

A3. The TKODP commenced the operation stage on 1 July 2024. This is the 4th Operation Phase Monthly EM&A Report, prepared by Aurecon, 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 first-year operation of Tseung Kwan O Desalination Plant in October 2024.

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

Summary of exceedance & investigation & follow-up

 

WATER QUALITY MONITORING

 

A5. The EM&A works for operation phase marine water quality were conducted during the reporting period in accordance with the EM&A Manual. Seventeen (17) of SS obtained had exceeded the Action Level. Twenty-nine (29) of SS obtained during the reporting period had exceeded the Limit Level.

A6. The EM&A works for continuous monitoring of effluent quality were conducted during the reporting period in accordance with the EM&A Manual. No exceedance of the sampling was obtained during the reporting period.

Ecology Impact Monitoring

 

A7.      Monthly operation phase coral monitoring works was conducted on 21 October 2024. There is no AL/LL exceedance during the monitoring period.

A8. Operation phase fishery monitoring for wet season 2024 was carried out on 24 and 31 August 2024. The survey findings showed that the abundance and diversity of fish eggs and larvae are on the low side for the Study Area, and the abundance and diversity of juveniles are very low for the Study Area. Survey findings also showed that there was a very week relationship in recorded families between ichthyoplankton assemblages, adult fish and juvenile fish in the Study Area, which implies that the Study Area does not appear to be an important spawning or nursery grounds for commercial fishes.

Landfill Gas Monitoring

 

A9.      In this reporting period, monthly landfill gas monitoring was conducted on 9 and 10 October 2024. No exceedances of action level and limit level was observed.

Weekly Site Inspections

 

A10. In this reporting period, site inspections were carried out by ET on 3, 8, 15, 22 and 28 October 2024. Joint site inspections of the operation work by ET were and IEC were carried out on 28 October 2024 to audit the mitigation measures implementation status.

Complaint Handling and Prosecution

 

A11. No environmental complaint, notification of summons and prosecution was received in the reporting period.

Reporting Change

 

A12. There was no change to be reported that may affect the on-going EM&A programme.

A13. According to the contractor’s information, the works of TKODP were substantially completed on 30 June 2024 and the plant commenced the operation phase on 1 July 2024. The outstanding construction works were being carried out during this reporting period. Details of the construction phase monitoring will be presented in the Construction Phase Monthly EM&A Report.

 

 

 

 

 


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 (TKODP) under Contract No. 13/WSD/17 (the Contract).

1.2.        Aurecon Hong Kong Limited (Aurecon) 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/B) to Water Supplies Department (WSD); and granted the Further Environmental Permit (No. FEP-01/503/2015/B) to AJCJV for the Contract.

The Reporting Scope

1.4.        This is the 4th Operation Phase Monthly EM&A Report for the Contract which summarizes the key findings of the EM&A programme of the Tseung Kwan O Desalination Plant Operation phase during the reporting period from 1 October 2024 to 31 October 2024.

Contract Organization

1.5.        The Contract Organization structure for Operation 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

Augustine Li

2608-7671

Chief Resident Engineer

David Wong

5229-8638

 

 

 

 

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

Operation Manager

Arnes Parra, Victor

6468-6710

Environmental Monitoring Manager

 

Tommy Law

 

6468-1782

Aurecon Hong Kong Limited

Environmental Team Leader

Toby Wan

9719-5422

Lam Environmental Services Limited

Independent Environmental Checker (IEC)

 

Serena Shek

 

6149-6683

 

Summary of Operation Works

 

1.7.        Details of the major operation activities undertaken in this reporting period are shown below.

1.8.        As informed by the Contractor, key activities carried out in this reporting period for the Contract included the followings:

-                 Potable Water Production

 

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

-                 Regularly monitoring of the effluent

-                 Sorting and storage of general refuse and operation waste

 


1.10.    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/B

Throughout the Contract

Valid

-Issued on 3 April 2024

FEP - 01/503/2015/B

Throughout the Contract

Valid

-Issued on 3 April 2024

Billing Account for Disposal

7036276

Throughout the Contract

Valid

-

Sludge (Special Waste) Disposal (Admission Ticket)

17913

01/07/2024

24/12/2024

Valid

 

17372

12/06/2024

31/12/2024

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.

-   Variation sampling point S.P.1 is approved by the EPD on 25 June 2024 (EPD ref.: EP640/W3/D1358/ 462874).

The       variation      of application                 of

discharge license was submitted on 9 Sep   2024   and

pending for EPD approval

1.11.    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.

Operation      phase      Marine      Impact Monitoring

On-going

Continuous Monitoring of Effluent Quality

 

On-going

Waste Management

Mitigation        Measures       in       Waste Management Plan

On-going

Landfill Gas

Monthly Monitoring for buildings, manholes and utility pits within the Project Site and along the fresh water

mains

 

On-going

Ecology (Coral)

Operation       phase       Regular       Coral Monitoring (Monthly)

 

On-going

Ecology (Fishery)

Operation     phase     Regular     Fishery Monitoring (Seasonally)

 

On-going

Landscape

Operation phase Landscape and Visual Site Inspection

 

On-going

Environmental Audit

Site Inspection covering Measures of Air Quality, Water Quality, Waste, Ecological           Quality,           Fisheries, Landscape and Visual

 

 

On-going

1.12.    Other than the EM&A work by ET, environmental briefings, trainings, and regular environmental management meetings were conducted, in order to enhance environmental awareness and closely monitor the environmental performance of the contractors.


1.13.    The EM&A programme has been implemented in accordance with the recommendations presented in the approved EIA Report and the EM&A Manual. A summary of implementation status of the environmental mitigation measures for the operation phase of the Contract during the reporting period is provided in Appendix B.

 

 

 

 

 


2.           Water Quality

 

2.1.        In accordance with the recommendations of the EIA, water quality monitoring is required 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.

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

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

(a) Operation phase Marine Water Quality Monitoring - first year upon commissioning (b)Continuous Monitoring of Effluent Quality

Water Quality Parameters

2.4.        Parameters to be measured in the marine water quality monitoring and the Continuous Monitoring of Effluent Quality are listed in Table 2.1 and Table 2.2 respectively.

a)  Operation phase Marine Water Quality Monitoring

2.5.        The parameters for the marine water quality monitoring 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 operation works or are a standard check on water quality conditions.

 

 

Table 2.1           Parameters measured in the 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

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-

*Remark: Anti-scalant water quality testing will only be conducted whenever anti-scalant dosage is adopted.

 


b)  Continuous Monitoring of Effluent Quality

2.6.        The monitoring requirement for the continuous effluent quality monitoring shall be conducted in accordance with the effluent parameters and standards stipulated by the Water Pollution Control Ordinance Discharge License (No.: WT00044188-2023) conditions.

Table 2.2  Parameters measured in the Continuous Monitoring of Effluent Quality

 

Parameters

Unit

Abbreviation

In-situ measurements

Temperature

oC

-

pH

pH

-

Salinity

0/00

-

Total Residual Chlorine

mg/L

TRC

Laboratory measurements

Suspended Solids

mg/L

SS

Iron-Soluble

mg/L

Fe

Total Inorganic Nitrogen

mg/L

-

Total Phosphorus

mg/L

-

Sodium Metabisulphite

mg/L

SMBS

Anti-scalant as Reactive Phosphorus *

mg/L

PO4 as P-

*Remark: Anti-scalant water quality testing will only be conducted whenever anti-scalant dosage is adopted.

 

2.7.        In addition to the marine 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

 

a)  Operation phase Marine Water Quality Monitoring

2.8.        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.

b)  Continuous Monitoring of Effluent Quality

2.9.        The equipment to be used for the effluent quality monitoring was summarizes in Table 2.3.

Table 2.3            Parameters measured in the Continuous Monitoring of Effluent Quality

 

Equipment

Model

 

Refrigerated Sampler

 

Teledyne ISCO 5800

Online sampler for real-time monitoring (Xylem WTW IQ SensorNet system and sensors)

DIQ/S 284-PR: Universal Transmitter to operate up to 4 digital IQ sensors, with PROFIBUS-connection

 

 


 

Equipment

Model

 

TetraCon® 700 IQ SW: Digital 4 electrode conductivity cell, in seawater design, suited for heavily polluted water, for use with the IQ SENSOR NET. With integrated temperature sensor

VisoTurb® 700 IQ SW: Digital turbidity sensor for industrial and seawater applications (ultrasonic cleaning) for use with the IQ SENSOR NET system

SensoLyt® 700 IQ SW: Robust digital pH/ORP sensor for SensoLyt® SEA/ DWA/ECA/PtA pH/ORP electrodes, in sea water design, for use with the IQ SENSOR NET. With built-in pre-amplifier and temperature sensor (NTC), with SensCheck function

FDO®700 IQ SW: Digital calibration free optical D.O. sensor (universal use). Optimized for measuring and controlling the O2 input in seawater applications, for use with IQ SENSOR NET. Factory calibrated system composed of sensor FDO® 700 IQ SW, membrane cap SCFDO® 700 and protective cap MSK FDO®

 

Chlorine 3017M: Online analyzer for photometric measurement of free and total chlorine, according to colorimetric DPD Method (ISO &US EPA); outputs (selectable): 4 to 20 mA or RS 485

Based on Section 5.1.3 of the EM&A Manual, the online sampler for real-time monitoring will be tested before use by HOKLAS-accredited laboratory and will be re-calibrated at monthly intervals throughout the stages of effluent quality monitoring.

Sampling / Testing Protocols

2.10.    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.

2.11.    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

 

a)  Operation phase Marine Water Quality Monitoring

2.12.    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.

2.13.    Parameters for laboratory measurements, standard methods and detection limits are presented in Table 2.4.

Table 2.4           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

APHA 4500CL: G

0.01mg/L

-

±25%

Anti-scalant*

Content acrylic polymers determination method

5 mg/L

-

-

 


 

*Remark: A proposal for update anti-scalant monitoring under the operation phase EM&A programme is proposed via email on 27 May 2024. EPD has agreed to update the anti-scalant monitoring detection limit, action and limit level from 0.2 mg/L to 5.0 mg/L (EPD ref. ()In EP 2/N8/E/120 Pt.14).

 

b)  Continuous Monitoring of Effluent Quality

2.14.       Analyses of the sample shall be carried out using American Public Health Association Standard Method for the Examination of Water and Wastewater or other internationally accepted standard methods proposed by the Licensee and approved by the Authority which could achieve the monitoring requirement.

Table 2.5            Measurements Methods for Continuous Monitoring of Effluent Quality

Parameters

 

Standard Methods

Flow Rate (m3 / day)

In-house method

Temperature(°C)

Instrumental

Salinity (0/00)

Instrumental

pH (pH units)

Instrumental

Suspended Solids (mg / L)

APHA 2540E

Iron (mg / L)

APHA 3111 B

Total Inorganic Nitrogen (mg / L)

In-house method

Total Phosphorous (mg / L)

In-house method

Total Residual Chlorine

APHA 4500CL: G

Sodium Metabisulphite

 

--

Anti-scalant ‘ACUMER’ 4035*

*Remark: Anti-scalant water quality testing will only be conducted whenever anti-scalant dosage is adopted.

 

 

Monitoring Location

 

a)  Operation phase Marine Water Quality Monitoring

2.15.    The operation phase water quality monitoring locations are in accordance with the EM&A Manual and detailed in Table 2.6 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 2.6            Location of 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

 

2.16.       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 2.1         Water Quality Monitoring Locations under EM&A Manual

 

b)  Continuous Monitoring of Effluent Quality

2.17.       In accordance with the discharge license, the Continuous Monitoring shall be sampling at Brine Outfall Shaft.


Figure 2.2         Continuous Monitoring locations

 

15

The copyright of this document is owned by Aurecon Hong Kong Limited. It may not be reproduced except with prior written approval from the Company.


Sampling Frequency

 

a)  Impact Marine Water Quality Monitoring

2.18.    Water quality monitoring was carried out three days per week during the operation 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.

b)  Continuous Monitoring of Effluent Quality

2.19.       The effluent should be collected in a full 24-hour period. Twenty four-hour flow- weighted composite effluent sample for subsequent chemical analysis and testing should be prepared by the following procedures:

-              Collect effluent sub-sample at bi-hourly interval over a 24 hour period

 

-              Obtain flow record of the Project for the 24-hour sampling period

 

-              Calculate the volume of each sub-sample for preparation of flow-weighted composite sample

-              Transfer the appropriate volume of sub-samples to a clean container and mix thoroughly

Sampling Depths & Replication

 

a)  Operation phase Marine Water Quality Monitoring

2.20.    During 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.

b)  Continuous Monitoring of Effluent Quality

2.21.    The effluent sampling should be planned carefully to ensure appropriate volume of effluent sub-samples is collected to prepare sufficient amount of flow-weighted composite effluent sample for carrying out subsequent chemical analysis and testing.

Action and Limit Levels

2.22.    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 2.7 and Table 2.8.

 


a)  Operation phase Marine Water Quality Monitoring

Table 2.7           Derived Action and Limit Levels for Water Quality

Parameters

Action

Limit

Operation phase Marine Water Quality 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

0.01 mg/L

0.01 mg/L

*Anti-scalant in            mg/L (Depth-

averaged)

5.0 mg/L

5.0 mg/L


 

Notes:

i. "Depth-averaged" is calculated by taking the arithmetic means of reading of all three depths.

ii. For DO, non-compliance of the water quality limits occurs when monitoring result is lower than the limits.

iii.  For Turbidity, SS, iron and Salinity, non-compliance of the water quality limits occurs when monitoring result is higher than the limits.

iv. *A proposal for update anti-scalant monitoring under the operation phase EM&A programme is proposed via email on 27 May 2024. EPD has agreed to update the anti-scalant monitoring detection limit, action and limit level from 0.2 mg/L to 5.0 mg/L (EPD ref. ()In EP 2/N8/E/120 Pt.14).

 

b) Continuous Monitoring of Effluent Quality

Table 2.8           Derived Limit Levels for Water Quality

Parameters

Limit

Continuous Monitoring of Effluent Quality

Flow Rate in m3/day

216841

Temperature in °C

Maximum 40

Salinity

71347

SS in mg/L

13

pH

6-9

Iron in mg/L

0.6

Total residual chlorine in mg/L

0.1

Total Inorganic Nitrogen in mg/L

2

Total Phosphorous in mg/L

1

Sodium Metabisulphite in mg/L

0.5

Anti scalant in mg/L*

2.2

*Remark:

1. Anti-scalant water quality testing will only be conducted whenever anti-scalant dosage is adopted.

 

 

Monitoring Results and Observations

 

a)  Operation phase Marine Water Quality Monitoring

2.23.    The operation phase of Tseung Kwan O Desalination Plant was commenced on 1 July 2024. Marine water quality monitoring for the operation phase of Tseung Kwan O Desalination Plant was conducted in the reporting period at the thirteen monitoring stations (CE, CF, WSR1, WSR2, WSR3, WSR4, WSR16, WSR33, WSR36, WSR37, NF1, NF2 and NF3). The

Action and Limit Level would be referred to the approved EM&A Manual Table 2.7.

2.24.    The marine water quality monitoring was conducted at the thirteen monitoring stations on 1, 3, 5, 8, 10, 12, 15, 17, 19, 22, 24, 26, 29 and 31 October 2024.

2.25.    Seventeen (17) of the operation phase water quality monitoring results of SS obtained had exceeded the Action Level. Twenty-nine (29) of SS obtained during the reporting period had exceeded the Limit Level.


2.26.    Investigation on the reason of exceedance has been carried out, where the exceedances of SS on 3, 5, 10, 12, 15, 17, 19, 22, 24, 26, 29 and 31 October 2024 were concluded to be unrelated to the Contract as detailed in the Incident Reports on Action Level or Limit Level Non-compliance along with supporting materials in Appendix K.

2.27.    Monitoring results of 8 key parameters: Salinity, DO, turbidity, SS, pH, temperature, Total Residual Chlorine and Iron in this reporting, are summarized in Table 2.9, and detailed results are presented in Appendix F.

b) Continuous Monitoring of Effluent Quality

2.28.    Continuous Monitoring of Effluent Quality was conducted sampling point in the reporting month. No exceedance of the sampling was obtained during the reporting period. The detailed results are summarized in Table 2.10, and presented in Appendix F.

 

 

 

 

 

 

Table 2.9           Summary of Impact Water Quality Monitoring Results

 

 

 

 

Locations

Parameters

 

 

Salinity (ppt)

Dissolved Oxygen (mg/L)

 

 

pH

 

 

Turbidity (NTU)

 

 

Suspended Solids (mg/L)

 

 

Temp. (oC)

 

 

TRC

(mg/L)

 

 

Iron (mg/L)

Surface & Middle

 

Bottom

 

CE

Avg.

32.40

8.90

8.89

8.19

2.44

4.60

28.64

<0.01

<0.1

Min.

30.94

7.90

7.89

8.08

2.01

2.50

27.78

<0.01

<0.1

Max.

33.12

9.64

9.67

8.31

2.79

37.00

29.38

<0.01

<0.1

 

CF

Avg.

32.55

8.83

8.82

8.24

2.28

7.68

28.65

<0.01

<0.1

Min.

31.71

7.98

7.80

8.09

1.86

2.50

27.81

<0.01

<0.1

Max.

33.56

9.84

9.74

8.40

2.68

86.00

29.38

<0.01

<0.1

 

WSR1

Avg.

32.21

8.67

8.67

8.24

1.83

7.90

28.60

<0.01

<0.1

Min.

31.41

7.70

7.72

8.05

1.30

2.50

27.73

<0.01

<0.1

Max.

33.04

9.36

9.40

8.40

2.22

65.00

29.26

<0.01

<0.1

 

WSR2

Avg.

32.52

8.87

8.85

8.21

1.65

5.01

28.59

<0.01

<0.1

Min.

31.59

7.99

7.95

8.04

1.34

2.50

27.69

<0.01

<0.1

Max.

33.59

9.64

9.65

8.33

2.22

63.00

29.30

<0.01

<0.1

 

WSR3

Avg.

32.52

8.91

8.90

8.22

1.68

4.10

28.59

<0.01

<0.1

Min.

31.52

8.16

8.13

8.03

1.22

2.50

27.91

<0.01

<0.1

Max.

33.05

9.86

9.86

8.39

2.08

12.00

29.22

<0.01

<0.1

 

WSR4

Avg.

32.52

8.96

8.99

8.21

1.81

4.40

28.64

<0.01

<0.1

Min.

31.56

7.75

7.78

8.00

1.31

2.00

27.93

<0.01

<0.1

Max.

33.33

9.60

9.61

8.41

2.16

13.00

29.33

<0.01

<0.1

 

WSR16

Avg.

32.35

8.76

8.75

8.20

1.76

4.29

28.58

<0.01

<0.1

Min.

31.24

8.14

8.12

8.06

1.44

2.50

27.72

<0.01

<0.1

Max.

33.13

9.49

9.55

8.34

2.14

11.00

29.19

<0.01

<0.1


 

 

 

Locations

Parameters

 

 

Salinity (ppt)

Dissolved Oxygen (mg/L)

 

 

pH

 

 

Turbidity (NTU)

 

 

Suspended Solids (mg/L)

 

 

Temp. (oC)

 

 

TRC

(mg/L)

 

 

Iron (mg/L)

Surface & Middle

 

Bottom

 

WSR33

Avg.

32.42

8.59

8.59

8.21

1.74

4.03

28.66

<0.01

<0.1

Min.

30.89

7.82

7.89

8.03

1.32

2.50

28.01

<0.01

<0.1

Max.

33.56

9.16

9.15

8.34

2.19

14.00

29.32

<0.01

<0.1

 

WSR36

Avg.

32.34

8.93

8.94

8.21

1.77

3.83

28.59

<0.01

<0.1

Min.

31.31

7.73

7.75

8.09

1.34

2.50

27.82

<0.01

<0.1

Max.

33.14

9.68

9.66

8.35

2.15

9.00

29.20

<0.01

<0.1

 

WSR37

Avg.

32.43

8.83

8.84

8.23

1.78

3.85

28.62

<0.01

<0.1

Min.

31.23

7.90

7.93

8.12

1.37

2.00

28.05

<0.01

<0.1

Max.

33.49

9.41

9.49

8.40

2.14

11.00

29.30

<0.01

<0.1

 

NF1

Avg.

32.35

8.76

8.75

8.21

1.77

4.19

28.64

<0.01

<0.1

Min.

31.55

8.27

8.22

8.11

1.33

2.50

27.76

<0.01

<0.1

Max.

33.36

9.28

9.22

8.39

2.18

13.00

29.38

<0.01

<0.1

 

NF2

Avg.

32.31

8.76

8.75

8.21

1.71

4.00

28.61

<0.01

<0.1

Min.

31.34

8.19

8.19

8.05

1.25

2.00

27.75

<0.01

<0.1

Max.

33.27

9.35

9.33

8.39

2.20

11.00

29.20

<0.01

<0.1

 

NF3

Avg.

32.25

8.75

8.73

8.24

1.83

3.64

28.60

<0.01

<0.1

Min.

31.45

7.81

7.78

8.07

1.47

2.00

27.81

<0.01

<0.1

Max.

33.08

9.61

9.55

8.36

2.22

11.00

29.30

<0.01

<0.1

Notes:

i.            "Avg", “Min” and “Max” is the average, minimum and maximum respectively of the data from measurements conducted under mid-flood and mid-ebb tides at three water depths, except that of DO where the data for “Surface & Middle” and “Bottom” are calculated separately.

ii.            Measurement data of Suspending Solids would be rounding to 2.5mg/L if the value was less than 2.5mg/L to facilitate data analysing.

 


Table 2.10        Summary of Continuous Effluent Monitoring Results

 

 

 

Sal (ppt)

 

pH

 

Temp (°C)

Total Residual Chlorine

(mg/L)

 

Suspended Solids (mg/L)

Total Inorganic Nitrogen

(mg/L)

Total Phosphorus (mg/L)

*Sodium Metabisulphite (mg/L)

 

Iron (mg/L)

Avg.

55.19

7.55

27.77