Hong Kong Shek Wu Hui

China, Hong Kong Shek Wu Hui

Hong Kong Drainage Services Department

The Shek Wu Hui Effluent Polishing Plant, also known as the Shek Wu Hui Sewage Treatment Works (SWHSTW) is operated and maintained by the Hong Kong Drainage Services Department (HK DSD). It treats sewage from the Sheung Shui and Fanling districts, with a capacity of 105,000 m3/d.

HK DSD decided to use Cambi’s thermal hydrolysis process as part of an expansion project aimed at increasing the capacity of the plant to 140,000 m3/d. In addition to thermal hydrolysis, the project will include sludge thickening, anaerobic digestion, CHP units with on-grid connection, dewatering, and sidestream centrate treatment. The primary purpose of the expansion project is to optimize the new digestion system.

Thermal hydrolysis will reduce the plant’s footprint - a key issue in Hong Kong, where space for expanding the plant is limited. The process will also contribute to increase biogas production and reduce the digestion construction cost. It will treat an average of 30,660 tDS/yr of indigenous primary sludge and a surplus of activated sludge. In the future, food waste will be added for co-digestion. The final cake after dewatering will be 30%DS at minimum, which meets the local incineration requirements.

Cambi’s scope includes two B6 systems with four reactors, pre-coolers, boilers, and digester coolers. Cambi acts as a subcontractor of Jardine Engineering Corporation in this project.

Cambi solution CambiTHP® - B6-4

Number of trains 2

Year of 2022 commissioning Primary and secondary sludge; Feedstock type food waste Population served 1,400,000 p.e.

Plant design capacity 30,660 tDS/yr Source: Shek Wu Hui Effluent Polishing Plant

Digester capacity 4 x 3,950 m3

Biogas utilisation Combined heat and power

Biosolids use Incineration

Cambi services Installation, Commissioning