Issue 11, Feb 2021

Yuen Long Effluent Polishing Plant: Another Pioneering Environmental Engineering Project by ATAL
元朗淨水設施 ﹕安樂最新環境工程先驅項目

ATAL has won another exciting environmental engineering project, which is to upgrade for the existing Yuen Long Sewage Treatment Works (YLSTW) commissioned in 1984 to become the Yuen Long Effluent Polishing Plant (YLEPP).

Currently serving residential areas in Yuen Long and the Yuen Long Industrial Estate, the YLSTW will see its treatment capacity expanded from 70,000 cubic metres per day to 100,000 cubic metres per day when transformed into the YLEPP, with treatment level upgraded to the highest level. The project will enable the plant to cope with forecast increase in sewage flow and future housing developments in the area.

Indeed, works have already begun in October 2020. Upon completion, the project will apply for the first time in Hong Kong breakthrough technologies such as the Aerobic Granular Sludge (AGS) treatment process, a compact and cost-effective biofilm technology that can remove carbon, nitrogen, phosphorous and other contaminants from wastewater. As AGS uses bacteria to remove nitrogen compounds from wastewater without adding chemicals, there is no risk of discharging plastic discharges to the aquatic environment and nearby beaches. The smaller footprint of an AGS treatment system also means significant energy reduction during its operation.

The YLEPP project covers the full range of civil works and electrical and mechanical (E&M) facilities, plus ancillary works such as roads and drainage systems. ATAL’s E&M subcontract covers the design, supply, delivery, installation, process start-up and testing and commissioning of the inlet works, the primary sedimentation tanks, the mainstream bio-reactor system, the tertiary treatment system, the sludge thickening system and sludge digestion system, the biogas holding and delivery system and other related works.

ATAL’s approach to sludge treatment also makes this project an excellent showcase in energy neutrality, circularity and value recovery. We shall use high-power ultrasound technology to pre-treat sludge, an advanced pre-treatment method that also gives rise to more biogas for power generation to operate the whole plant, bringing the facility closer to energy neutrality. This is also consistent with the concept of circularity which aims to create a self-sustaining economic system to eliminate waste and enable the continual use of resources. Value recovery will be achieved too, as the remaining value in the sludge is recovered in the form of biogas for power generation, instead of being dumped and wasted.

Using AGS and other innovative technologies, the project will not only enhance the quality of water in the receiving water bodies, but also translate into high sustainability performance and positive life cycle assessment for the entire plant.

“This landmark environmental infrastructure project will provide Hong Kong with a cost-effective and very sustainable wastewater treatment solution,” noted Ir Raymond Chan, Executive Director of ATAL Engineering Group. The upgraded plant will be resilient and can easily integrate with new technological options as they arise, making it future-proof.

“ATAL has always been committed to improving the environment via smart engineering solutions, and we look forward to helping make Hong Kong a greener city,” Ir Chan said.

The existing Yuen Long Sewage Treatment Works serves Yuen Long Town, Yuen Long Industrial Estate and Kam Tin areas with a design capacity of 70,000 cubic metres per day

The plant will be upgraded to an effluent polishing plant with tertiary treatment level