1 INTRODUCTION

1.1.1 The existing Yuen Long Sewage Treatment Works (YLSTW) is a secondary sewage treatment works, located at Yuen Long Industrial Estate serves Yuen Long Town, Yuen Long Industrial Estate and Kam Tin areas with a design capacity of 70,000 m³ per day. Based on the latest planning data, the volume of sewage generation from the YLSTW catchment is estimated to increase to 150,000 m³ per day after 20 years. In addition, since YLSTW has been operating for over 30 years and most of its facilities are of out-dated design and reaching the end of their design life, the environmental facilities of the plant will also be upgraded and hence improving the adjacent environment through upgrading the YLSTW to Yuen Long Effluent Polishing Plant (YLEPP). The Location of Proposed Yuen Long Effluent Polishing Plant is given in Figure 1.

1.1.2 YLSTW will be reconstructed in two stages to increase its capacity to 150,000 m³ per day. The proposed works, as Stage 1 of the project, will firstly increase the treatment capacity to 100,000 m³ per day. In the course of Stage 1 construction, about half of the existing facilities of YLSTW would be demolished, while the other half would be kept in operation to maintain the sewage treatment service for Yuen Long area. This 72-month works contract (Contract DC/2019/10) commenced on 9 November 2020. Demolition of existing YLSTW for construction of new treatment facilities are in progress.

1.1.3 Under Contract DE/2020/01, this 54-month works contract commenced on 13 June 2022. Design and installation of E&M system, and the supply and installation of PV panels are in progress.

1.1.4 The Project is a designated project under Schedule 2 of the Environmental Impact Assessment Ordinance (EIAO) (Cap. 499) for which Environmental Impact Assessment (EIA) report and Environmental Monitoring and Audit (EM&A) Manual was approved by EPD (Register No.: AEIAR-220/2019) on 25 April 2019. The Environmental Permit (EP) (EP No. EP-565/2019) was issued by EPD on 26 April 2019. Variation of the Environmental Permit (EP) (EP No. EP-565/2019/A) was issued by EPD on 26 November 2024.

1.1.5 Fugro Technical Services Limited was appointed as the Environmental Team (ET) by Drainage Services Department (DSD) to undertake the Environmental Team services for the Project and implement the EM&A works under the Contract No. DC/2019/10 Yuen Long Effluent Polishing Plant -Main Works for Stage 1 (hereinafter referred as “the Contract”) for the period from July 2020 to 6 July 2023.

1.1.1 Aurecon Hong Kong Limited (Aurecon) has been appointed as the Environmental Team (ET) by Drainage Services Department (DSD) to undertake the Environmental Team services for the Project and implement the EM&A works under the Contract from July 2023. Air quality, noise, water quality and ecological monitoring, site inspections and auditing (as scheduled) under EM&A programme with effect from 7 July 2023 was conducted by Aurecon. Aurecon is undertaking the preparation (including reporting of monitoring results), certification by ET Leader and submission of this report to EPD.

1.1.2 All ET roles and responsibilities under the EP for this Project were undertaken by Fugro up to 6 July 2023 and by Aurecon with effect from 7 July 2023. Air quality, noise, water quality and ecological monitoring, site inspections and auditing (as scheduled) under EM&A programme up to 6 July 2023 was conducted by Fugro, and the corresponding monitoring results were shared with Aurecon for the purposes of reporting in this report.

1.1.3 This is the 57^th Monthly EM&A report to document the findings of site inspection activities and EM&A programme for this project from 1 December 2025 to 31 December 2025 (reporting period) and is submitted to fulfil Condition 3.4 of the EP and Section 12.4.1 of the EM&A Manual. According to Condition 4 of the EP, electronic reporting is provided on the internet website to facilitate public inspection of the report.

1.2 Project Organization

1.2.1 The Project Organization structure is shown in Appendix B. The key personnel contact names and numbers are summarized in Table 1.

1.3 Construction Programme and Activities

1.3.1 The construction programme of this project is shown in Appendix A.

1.4 Works undertaken during the month

1.4.1 The main construction works carried out in the reporting period were as follow:

Contract DC/2019/10:

· Fixing GRC panel at CLP Substation

· ELS Works and Pipe works for Modification of Existing Inspection Chamber and Inlet Effluent Pipes from NSWSPS

· T&C Works at IW

· RC, ABWF and E&M works at IW (Remaining area)

· RC, ABWF and E&M works at PST Stage 2

· ELS work and RC work at SDB

· Predrill works and ELS work at ADB

· External works at site-wide include water meter cabinet

· RC structure at AGS

· RC structure at TTS

· ABWF and E&M work at STB

· RC and E&M work at H2S

· ELS work at UC3

· RC structure at Sludge Digester no. 1-3 with PP1

· ELS work at Sludge Digester no. 4-6

· RC work at Biogas Holder no. 2-3 foundation

Contact DE/2020/01:

· Installation of PC panels

1.4.2 The environmental mitigation measures corresponding to the main construction works implemented in the reporting period can be referred to Appendix J.

1.5 Status of Environmental Licences, Notification and Permits

1.5.1 A summary of the status of the relevant permits, licenses and/or notifications on environmental protection for this project is presented in Table 2.