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).

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.

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.

The scopes of works under the Project (Stage 1) are listed below:

• the demolition and reconstruction of part of the existing YLSTW to increase its treatment capacity from 70 000 m³ per day to 100 000 m³ per day and upgrading of sewage treatment level to tertiary effluent polishing standard;
• the demolition and reconstruction of sludge treatment facilities;
• the demolition and reconstruction of the administration building, storage building, switchgear house and transformer house;
• ancillary works, such as utilities diversion, provision of manholes, walkway, necessary building services and landscaping works; and
• environmental mitigation measures including comprehensive odour control/mitigation measures.

To upgrade the effluent standards and the treatment capacity of YLEPP

• upgrade the sewage treatment level from secondary effluent treatment to tertiary effluent polishing standard (for More Information)
• increase the treatment capacity of YLEPP from 70 000 m³ per day to 100 000 m³ (Stage 1)