+Contract No. CM 04/2024 –

Outlying Islands Sewerage Stage 2 – South Lantau Sewerage Works – Environmental Team Services (2025 - 2027)

Quarterly Environmental Monitoring, and Audit Report for:

August to October 2025

Revision 1

 

Certified By:

 

 

 

______________

Ting Po Chung, Ivan

Environmental Team Leader

Report Date: 24 December 2025

 

 


 


Content:

 

1.         Introduction. 1

1.1       Project Background. 1

1.2       Environmental Monitoring & Audit Programme. 1

1.3       Quarterly Environmental Monitoring & Audit Report 2

2.         Basic project Information and Environmental Status. 3

2.1       Basic Project Information. 3

2.2       Construction Programme. 3

2.3       Works undertaken during the Reporting quarter 4

3.         Environmental Monitoring and Audit (“EM&A”) Requirement 5

3.1       Summary of Monitoring Parameters. 5

3.2       Environmental quality performance limits (Action and Limit levels); and Results Summary. 5

3.3       Implementation Status of Environmental Mitigation Measures. 7

3.4       Complaints, Non-Compliance, and Notification of Summons and Prosecution. 8

4.         Conclusion. 9

4.1       Environmental Monitoring and Audits. 9

4.2       Implementation of Environmental Mitigation Measures. 9

 

 

 

Tables:

 

Table 2.1:     Contact Details of Key Personnel

Table 3.1:     Summary of Impact EM&A Requirements

Table 3.2:     Action and Limit Levels for Noise Monitoring

Table 3.3:     Action and Limit Levels for Water Quality

Table 3.4:     Summary of Ecological Impact Monitoring

Table 3.5:     Summary of Quantities of Waste Material in the Reporting Quarter

 

Figures:

 

Figure 2.1        Master Layout Plan

Figure 3.1        Locations of Noise Monitoring Station

Figure 3.2        Locations of Water Quality Monitoring Station

 

Appendices:

 

Appendix 3.1    Noise Monitoring Graphical Presentations

Appendix 3.2    Final Investigation Report

Appendix 3.3    Waste Material in the Reporting Quarter

 

 


Executive Summary

This Quarterly Environmental Monitoring and Audit (“EM&A”) Report summarises project monitoring, and auditing data, with full interpretation illustrating the acceptability or otherwise of any environmental impacts, and identification or assessment of the implementation status of agreed mitigation measures, including monitoring results, and findings of the EM&A Programme, along with findings recorded during the site Inspections, and audits, reports of Complaints, Notifications of Summons, and Successful Prosecutions, and other necessary observations obtained within this reporting quarter from 1 August 2025 to 31 October 2025.

Key Construction Works in the Reporting quarter

San Shek Wan Sewage Treatment Works (“SSWSTW”)

·         Excavation and site formation

·         Superstructure Reinforced Concrete (“RC”) works

·         Waterproofing work

Pui O Sewage Pumping Station (“POSPS”)

·         Excavation and Excavation and Lateral Support (”ELS”) work

·         Electrical and Mechanical (“E&M”) Installation

Lo Uk Tsuen, Pui O

·         Excavation, sewer laying, construction of manhole

South Lantau Road

·         Excavation, sewer laying, construction of manhole

Chi Ma Wan Road

·         Excavation, sewer laying, construction of manhole

·         Trenchless drilling works

Environmental Monitoring, and Audit Progress

The EM&A Programme is implemented in accordance with the EM&A Manual under the EIA Report. A summary of the monitoring activities during this reporting quarter as below:

 

Monitoring Activity

Monitoring Date

August 2025

September 2025

October 2025

Noise

7-8, 11, 22 and 28

3-4, 9-10, 15-16 and

25-26

6, 9-10, 14-15, 23 and 31

Water Quality

N/A

N/A

N/A

Nursery visit for transplanted trees

27

22

20

Site Inspection

4, 11, 18 and 27

1, 9, 15, 22 and 30

6, 13, 20 and 27

 

Breaches of Action, and Limit Levels

Subsequent to the completion of marine work on 24 May 2025, water quality monitoring was considered completed by 30 May 2025. No water quality monitoring is conducted in this reporting quarter. Should marine works resume, water quality monitoring will be conducted in accordance with the requirement stipulated in the EM&A Manual accordingly.

A summary of environmental exceedances for this reporting quarter is as follows:

Environmental Monitoring

Parameters

Action Level

Limit Level

Noise

Leq (30 min)

0

0

Water Quality

Suspended solids level (“SS”)

0

0

Turbidity level

0

0

Dissolved oxygen level (“DO”)

0

0

 

Ecological Impact Monitoring

Transplanting of the trees of Aquilaris sinensis was completed on 26 April 2022. Maintenance works for trees in holding nursery have commenced.

4 trees found (1 no. of Aquilaria sinensis, and 3 nos. of Gmelina chinensis) within the site of SSWSTW which are considered to be the plant species with conservative importance for temporarily transplanted to the nursery at Kam Tin, and eventually be transplanted to POSPS.

The weekly site audit was carried out by ET include checking whether good site practices are being properly implemented by the Contractor.

The extent of the work site boundaries was checked by the ET during the weekly site audit.

Complaints, Notification of Summons and Prosecution

On 16 September 2025, the received complaint was related to a reported oil sheen observed in the wetland area near Pui O Wetland, Lantau Island. On 25 September 2025, additional information from EPD was received that oil signs spotted in the Pui O. Subsequent investigations have been conducted.

An unannounced inspection conducted by ET on 17 September 2025, joint site investigation conducted by ET and the Contractor on 18 September 2025, and a joint site investigation conducted by ET, EPD, and the Contractor on 25 September 2025, and the subsequent site inspection conducted with ET, and Contractor on the same day. Preliminary findings showed that the diesel drum stored within the Project Sites were stored properly with no leakage or spillage. No oil signs within the project sites were found during the inspections conducted throughout the period of complaint investigation. Also, locations of the identified oil sheen are not within proximity of the Project Site.

The Final Investigation Report was submitted to EPD on 17 October 2025. Given that there is no evidence of oil leakage within our project site, it is considered that the oil pollution was not caused by our site operations. As such, the case is considered closed.

No notification of summons and successful prosecution regarding construction works were recorded in the reporting quarter.

Reporting Changes

There are no reporting changes in the reporting quarter.

 


1.                 Introduction

1.1              Project Background

1.1.1          The Environmental Protection Department (“EPD”) completed the Outlying Islands Sewerage Master Plan (“SMP”) Study in 1994 and drew up a SMP for Lantau Island and other outlying islands. The proposed sewerage works of the SMP were divided into 2 stages. The Stage 2 Works of the SMP were subsequently reviewed by EPD under the Outlying Islands Sewerage Master Plan Stage 2 Review (SMP Review Study) in 2001.

1.1.2          The proposed sewerage works for South Lantau were further reviewed in 2008 under the Review of Sewerage Scheme for South Lantau (Review Study). According to the Review Study, the proposed sewerage works for South Lantau would serve the unsewered areas of Shui Hau, Tong Fuk, Cheung Sha, San Shek Wan, Pui O and Ham Tin.

1.1.3          The Outlying Islands Sewerage Stage 2 – South Lantau Sewerage Works, herein referred to as “the Project”, referred to the sewerage works for South Lantau that would serve the unsewered areas of Shui Hau, Tong Fuk, Cheung Sha, San Shek Wan, Pui O and Ham Tin.

1.1.4          The Project mainly comprises of the following items:

a)  Construction of a secondary sewage treatment works (“STW”) at San Shek Wan in South Lantau;

b)  Construction of sewage pumping station (“SPS”) at Pui O, San Shek Wan, Cheung Sha, Cheung Fu Street, Shui Hau and Tong Fuk;

c)  Construction of about 1.4km of twin submarine outfalls with a diameter of 350mm for the disposal of treated effluent from the STW at San Shek Wan;

d)  Construction of about 10.1km of gravity sewers with diameters ranging from 150mm to 375mm along South Lantau Road and Chi Ma Wan Road and at Pui O; and

e)  Construction of about 3.1km of twin rising mains with a diameter of 200mm to 250mm along South Lantau Road and Chi Ma Wan Road.

1.2              Environmental Monitoring & Audit Programme

1.2.1          An Environmental Impact Assessment (“EIA”) was subsequently prepared to review the potential environmental impact that would be due to the Project during its construction works and operational works. The EIA Report was submitted and approved on 24 April 2017, and Environmental Permit (“EP”) No. EP-538/2017 was subsequently granted on 13 July 2017.

1.2.2          The EM&A Programme is therefore implemented in accordance with the EM&A Manual under the EIA Report.

1.2.3          Umwelt Consulting Limited (“UCL”) has been appointed to work as the Environmental Team (“ET”) under EP No. EP-538/2017 to implement the EM&A programme as stipulated in the EM&A Manual of the approved EIA Report for the Outlying Islands Sewerage Stage 2 – South Lantau Sewerage Works (Register No.: AEIAR-210/2017).

1.3              Quarterly Environmental Monitoring & Audit Report

1.3.1          This Quarterly EM&A Report summarises project monitoring and auditing data, with full interpretation illustrating the acceptability or otherwise of any environmental impacts and identification or assessment of the implementation status of agreed mitigation measures, including monitoring results and findings of the EM&A Programme, along with findings recorded during the site Inspections and audits, reports of Complaints, Notifications of Summons and Successful Prosecutions, and other necessary observations obtained within this reporting quarter form August 2025 to October 2025.

2.                 Basic project Information and Environmental Status

2.1              Basic Project Information

2.1.1          Drainage Services Department (“DSD”) is the project proponent and the permit holder of the Project. For the construction phase of the Project, Contractor(s), ET and Independent Environmental Checker (“IEC”) are appointed to manage and control environmental issues. Key personnel and contact particulars are summarized in Table 2.1.

2.1.2          Upon conclusion of Contract No: SD 15/2022 Outlying Island Sewerage Stage 2 – South Lantau Sewage Works – Environmental Team Services (2023 – 2024), the subsequent contract, Contract No. CM 04/2024 Outlying Islands Sewerage Stage 2 – South Lantau Sewerage Works – Environmental Team Services (2025-2027), has been awarded to Umwelt Consulting Limited (“UCL”) starting 1 February 2025. As such the environmental team leader (“ETL”) appointed for the Project has been updated to Mr. Ting Po Chung, Ivan since 1 February 2025. His contact details has been updated in Table 2.1.

2.1.3          There are no other reporting changes in the reporting quarter.

Table 2.1:    Contact Details of Key Personnel

Party

Role

Post

Name

Contact No.

Contact Fax

Drainage Services Department

The Engineer for the Contract

Engineer

Mr. KK Chan

2594 7297

3104 6426

Binnies Hong Kong Limited

Engineer’s Representative

Resident Engineer

Mr. Kevin Chan

3529 3003

-

Kwan Lee – Chun Wo Joint Venture

Contractor

Sub Agent

Mr. Daniel Chu

6737 6701

2744 6937

Environmental Supervisor

Ms. Joey Pang

6978 2876

Environmental Supervisor

Mr. Philip Wong

6908 8920

SMEC Hong Kong

IEC

IEC

Ms. Kitty Lee

3995 8140

3422 3631

Umwelt Consulting Limited

ET

ET Leader

Mr. Ivan Ting

3756 9590

3582 3310

 

2.2              Construction Programme

2.2.1          The proposed sewerage works will collect the sewage generated from the unsewered areas of Shui Hau, Tong Fuk, Cheung Sha, San Shek Wan, Pui O and Ham Tin in South Lantau (i.e. within the Project Catchment Area) and convey it to a proposed sewage treatment works at San Shek Wan for treatment and disposal into outer bay of Pui O / Chi Ma Wan via a submarine outfall.

2.2.2          The Project was divided into 3 contracts. The current contract, Contract No. DC/2020/02 - Construction of San Shek Wan Sewage Treatment Works, Associated Submarine Outfall and Pui O Sewerage Works (“the Contract”) would have the following implementations. The works site of the Contract is also given in Figure 2.1.

2.2.3          The major components of the Contract under Environmental Permit (“EP”) (EP No. EP-538/2017) comprises:

a)  Construction of a secondary sewage treatment works (“STW”) at San Shek Wan in South Lantau;

b)  Construction of a sewage pumping station (“SPS”) at Pui O, San Shek Wan, Cheung Sha and Cheung Fu Street;

c)  Construction of about 1.4km of submarine outfall with a diameter of 350mm for the disposal of treated effluent from the STW at San Shek Wan;

d)  Construction of about 10.1km of gravity sewers with diameters ranging from 150mm to 375mm along South Lantau Road and Chi Ma Wan road and at Pui O; and

e)  Construction of about 3.1km twin rising mains with a diameter of 200mm to 250mm along South Lantau Road and Chi Ma Wan Road.

2.3              Works undertaken during the Reporting quarter

2.3.1          In the reporting quarter, the principal work activities conducted are as follow:

San Shek Wan Sewage Treatment Works (“SSWSTW”)

a)  Excavation and site formation

b)  Superstructure Reinforced Concrete (“RC”) works

c)  Waterproofing work

Pui O Sewage Pumping Station (“POSPS”)

a)  Excavation and Excavation and Lateral Support (”ELS”) work

b)  Electrical and Mechanical (“E&M”) Installation

Lo Uk Tsuen, Pui O

a)  Excavation, Sewer Laying, and Construction of Manhole

South Lantau Road

a)  Excavation, Sewer Laying, and Construction of Manhole

Chi Ma Wan Road

a)  Excavation, Sewer Laying, and Construction of Manhole

b)  Trenchless drilling works

3.                 Environmental Monitoring and Audit (“EM&A”) Requirement

3.1              Summary of Monitoring Parameters

3.1.1          The EM&A programme requires environmental monitoring, noise monitoring, water quality monitoring, and ecology as specified in the approved EM&A Manual.

3.1.2          A summary of Impact EM&A requirements is presented in Table 3.1. The locations of noise monitoring stations, and water quality monitoring stations are shown in Figure 3.1 and Figure 3.2 respectively.

Table 3.1:    Summary of Impact EM&A Requirements

Environmental Monitoring Aspects

Parameters and Unit

Monitoring Station

Frequencies

Remarks

Noise

Leq (30mins),

L10 (30mins) and

L90 (30mins)

N12a, N12b, N13, N14, N15b, N16a, N16b, and N17

At least once per week

Daytime on normal weekdays (0700-1900 hrs).

Water Quality

Dissolved Oxygen, mg/L

Temperature, °C

Salinity, 0/00

Turbidity, NTU

Suspended Solids, mg/L

pH

CE, CF, SR4, SR5, SR6, SR9, SR10, SR12, and SR15

Three times per week during mid-ebb, and mid-flood tides

Samples are collected at 3 depths (1 m below water, mid-depth, and 1 m above seabed) shall be collected.

Where the water depth is less than 6 m, in which case the mid-depth station may be omitted.

Should the water depth be less than 3 m, only the mid-depth station will be monitored

 

 

3.2              Environmental quality performance limits (Action and Limit levels); and Results Summary

Noise Monitoring

3.2.1          A-weighted equivalent continuous sound pressure level (“Leq”) over a period of 30 minutes Leq (30min) shall be used as the monitoring parameter for construction noise monitoring. Supplementary information for data auditing, statistical results such as L10, and L90 should also be recorded for reference.

3.2.2          For impact monitoring of construction works, noise monitoring should be undertaken on weekly basis. Six consecutive Leq (5min) between 07:00-19:00 hours on normal weekdays is taken in this EM&A Programme.

3.2.3          The Action and Limit Levels for noise monitoring are given as in Table 3.2. No examination was conducted during the reporting quarter.

Table 3.2: Action and Limit Levels for Noise Monitoring

Monitoring Station ID

Monitoring Location

Action Level

Limit Level

N12a

Lo Uk Tsuen

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

75 dB(A)

N12b

Lo Uk Tsuen

75 dB(A)

N13

Pui O San Wai Tsuen

75 dB(A)

N14

South Lantau Community Centre

75 dB(A)

N15b

Pui O Lo Wai Tsuen

75 dB(A)

N16a

Residences at Ham Tin

75 dB(A)

N16b

Residences at Ham Tin

75 dB(A)

N17

Bui O Public School

70 dB(A) / 65 dB(A) 1

Note:

1. The Limit Level for N17 is 70 dB(A) for being an educational institution. The Limit Level is reduced to 65 dB(A) during school examination period.

3.2.4          No exceedance was recorded for the reporting quarter. The detailed results and graphical plot for noise monitoring is given in Appendix 3.1.

Water Quality Monitoring

Completion of Water Quality Monitoring

3.2.5          Subsequent to the completion of marine work on 24 May 2025, water quality monitoring

was considered completed by 30 May 2025. No water quality monitoring is conducted in August to October 2025.

3.2.6          Should marine works resume, water quality monitoring will be conducted in accordance

with the requirement stipulated in the EM&A Manual accordingly.

Ecological Impact Monitoring

3.2.7          Monitoring in the form of regular site inspections should be carried out to ensure ecological measures in the form of tree transplantation, and establishment are being implemented, and effective for plant species of conservation importance (e.g. Aquilaria sinensis).

3.2.8          Transplanting works for plant species, Aquilaris sinensis, was completed on 26 April 2022. Maintenance works for trees in holding nursery have commenced.

3.2.9          Monitoring of maintenance works for the transplanted plant species was conducted at the holding nursery while in the reporting period.

3.2.10       As per latest version of PTP, four tree found (1 no. of Aquilaria sinensis, and 3 nos. of Gmelina chinensis) within the site of SSWSTW which are considered to be the plant species with conservative importance for temporarily transplanted to the nursery at Kam Tin and eventually be transplanted to POSPS.

3.2.11       Within this reporting period, holding nursery visit for transplanted trees on 27 August, 22 September and 20 October 2025.

3.2.12       No non-compliance was found during the site inspection while reminders on environmental measures were recommended. Results and findings of these inspections in this reporting period are listed below in Table 3.4.

Table 3.4: Summary of Ecological Impact Monitoring

Inspection Date

Reminder and Recommendations

Close-out Date / Status

27 August 2025

Nil

--

22 September 2025

Nil.

--

20 October 2025

Nil.

--

Waste Management

3.2.13       The quantities of waste for disposal in present quarter are summarized in Table 3.5.

Table 3.5:    Summary of Quantities of Waste Material in the Reporting Quarter

Waste Type

Quantity for Reporting Quarter

Cumulative Quantity-to-Day

Hard Rock and Large Broken Concrete (Inert), in ‘000m3

0

0

Reused in this Contract (Inert),in ‘000m3

0

0

Reused in other Projects (Inert), in ‘000m3

0

0

Disposal as Public Fill (Inert), in ‘000m3

0.71

30.62789

Metals (in ‘000kg)

30.9471

113.98617

Paper / Cardboard Packing, in ‘000kg

0.1704

1.37028

Plastics in ‘000kg

0.0071

0.11216

Chemical Waste in ‘000kg

0

0

General Refuse in ‘000kg

186.51

1083.83

Note:

The table is summary of quantities of waste material of August to October period.

3.3              Implementation Status of Environmental Mitigation Measures

3.3.1          The mitigation measures recommended in the EIA Report has been implemented where applicable. The implemented mitigation measures for the reporting quarter are listed below:

a)  Implementation of noise mitigation measures in accordance with Construction Noise Mitigation Plan, including the use of quality powered mechanical equipment, use of noise barriers, and locating noisy equipment away from noise sensitive receivers as far as possible;

b)  Dust control during dust generating works, including watering of construction works site, covering the stockpile stored on site, provision of wheel-washing facilities for vehicles at the site entrance;

c)  Adopt surface drainage and sediment control facilities for sewage installation in village and public roads;

d)  Adopt temporary drainage and sediment control facilities on Site; and

e)  Proper waste handling, recycling and storage.

3.3.2          The implemented mitigation measures are considered effective.

3.4              Complaints, Non-Compliance, and Notification of Summons and Prosecution

Environmental Complaints Received

3.4.1          On 16 September 2025, the received complaint was related to a reported oil sheen observed in the wetland area near Pui O Wetland, Lantau Island. On 25 September 2025, additional information from EPD was received that oil signs spotted in the Pui O. Subsequent investigations have been conducted.

3.4.2          An unannounced inspection conducted by ET on 17 September 2025, joint site investigation conducted by ET and the Contractor on 18 September 2025, and a joint site investigation conducted by ET, EPD, and the Contractor on 25 September 2025, and the subsequent site inspection conducted with ET, and Contractor on the same day. Preliminary findings showed that the diesel drum stored within the Project Sites were stored properly with no leakage or spillage. No oil signs within the project sites were found during the inspections conducted throughout the period of complaint investigation. Also, locations of the identified oil sheen are not within proximity of the Project Site.

3.4.3          The Final Investigation Report was submitted to EPD on 17 October 2025. Given that there is no evidence of oil leakage within our project site, it is considered that the oil pollution was not caused by our site operations. As such, the case is considered closed. The Final Investigation Report is given in Appendix 3.2.

3.4.4          No notification of summons and successful prosecution regarding construction works were recorded in the reporting quarter.

Environmental Non-Compliance

3.4.5          No environmental non-compliance was recorded in the reporting quarter.

Notifications of Summons and Successful Prosecutions

3.4.6          No notification of summons and successful prosecution regarding construction works were recorded in the reporting quarter.

 

4.                 Conclusion

4.1              Environmental Monitoring and Audits

4.1.1          Environmental monitoring and audits including Noise, Water Quality, Ecology, and Site audits have been conducted in the reporting quarter in accordance with the requirement stipulated in the EM&A Manua.

Noise Monitoring

4.1.2          Noise Monitoring has been conducted at 8 of the designated monitoring locations where construction works has been conducted nearby during the reporting period.

4.1.3          No action or limit level exceedance was recorded in construction noise level in this reporting period.

Water Quality Monitoring

4.1.4          Subsequent to the completion of marine work on 24 May 2025, water quality monitoring was considered completed by 30 May 2025. No water quality monitoring is conducted in this reporting period.

Ecological Impact Monitoring

4.1.5          Transplanting of the trees of Aquilaris sinensis was completed on 26 April 2022. Maintenance works for trees in holding nursery have commenced.

4.1.6          As per latest version of PTP, 4 tree found (1 no. of Aquilaria sinensis and 3 nos. of Gmelina chinensis) within the site of SSWSTW which are considered to be the plant species with conservative importance for temporarily transplanted to the nursery at Kam Tin and eventually be transplanted to Pui O Pumping Station.

4.1.7          The weekly site audit was carried out by ET include checking whether good site practices are being properly implemented by the Contractor.

4.1.8          The extent of the work site boundaries was checked by the ET during the weekly site audit.

4.1.9          No non-compliance was found during the site inspection while reminders on environmental measures were recommended.

4.2              Complaints, Notification of Summons and Prosecution

4.2.1          On 16 September 2025, the received complaint was related to a reported oil sheen observed in the wetland area near Pui O Wetland, Lantau Island. On 25 September 2025, additional information from EPD was received that oil signs spotted in the Pui O. Subsequent investigations have been conducted.

4.2.2          An unannounced inspection conducted by ET on 17 September 2025, joint site investigation conducted by ET and the Contractor on 18 September 2025, and a joint site investigation conducted by ET, EPD, and the Contractor on 25 September 2025, and the subsequent site inspection conducted with ET, and Contractor on the same day. Preliminary findings showed that the diesel drum stored within the Project Sites were stored properly with no leakage or spillage. No oil signs within the project sites were found during the inspections conducted throughout the period of complaint investigation. Also, locations of the identified oil sheen are not within proximity of the Project Site.

4.2.3          The Final Investigation Report was submitted to EPD on 17 October 2025. Given that there is no evidence of oil leakage within our project site, it is considered that the oil pollution was not caused by our site operations. As such, the case is considered closed.

4.2.4          No notification of summons and successful prosecution regarding construction works were recorded in the reporting period.

4.3              Implementation of Environmental Mitigation Measures

4.3.1          The mitigation measures recommended in the EIA Report has been implemented where applicable. The implemented mitigation measures are considered effective.