Throughout the years, DSD has been introducing cutting-edge engineering technologies and strategic measures in environmental management. We incorporate sustainability elements into all aspects of work and actively promote the concept of sustainable development, covering water resources management, roof greening, energy conservation and emissions reduction, to make the projects blends with the natural environment and mitigate environmental impacts.
Water Resources Management
DSD has incorporated the concept of water resources management into our newly constructed facilities to improve the water resources utilisation rates and step up harvesting and reusing precious water resources so as to support sustainable development. Some major design elements include water harvesting systems, underground stormwater storage systems, rain gardens and porous pavements, etc.
Water Harvesting System
Water Harvesting System of Happy Valley Underground Stormwater Storage Scheme (HVUSSS)
DSD constructed a water harvesting system under the HVUSSS to collect groundwater, irrigation water and rainwater from sports pitches. As the collected water is of better quality, it can attain the standard of reclaimed water for non-potable use after simple disinfection and be reused for irrigation at 11 football pitches and toilet flushing at two changing rooms within the Happy Valley Recreation Ground (HVRG) and two public toilets in the vicinity to save precious drinking water. The system also supplied reclaimed water to the Food and Environmental Hygiene Department (FEHD) for street cleaning in Happy Valley and Wan Chai districts.
Lai Chi Kok Drainage Tunnel Stormwater Harvesting System
DSD incorporated the concept of sustainable development into the design of Lai Chi Kok Drainage Tunnel (the Tunnel). The water resources collected from the Tunnel catchment area are filtered and disinfected by chlorination. Since the Tunnel came into operation in 2014, the treated stormwater has been supplied to Butterfly Valley Road Pet Garden for toilet flushing, irrigation and cleansing.
Rainwater Harvesting Facilities at Kowloon City No. 1 and No. 2 Sewage Pumping Stations
Kowloon City No. 1 and No. 2 Sewage Pumping Stations in Kai Tak incorported a number of water resources management features, including rain garden and rainwater harvesting facilities, etc. The rain garden filters rainwater with plants and soil to improve runoff quality and reduce discharge into underground channels. The roofs are paved with porous materials to facilitate rainwater collection. Harvested rainwater is treated by sand filtration and ultraviolet (UV) disinfection for irrigation, water cascade and other non-potable uses, thus reducing water consumption effectively. The pumping stations are also installed with devices such as rainfall sensors, water retention layer and water consumption monitoring system to further enhance the water utilisation rate.
In line with the Government's initiative to use reclaimed water under the Total Water Management Strategy, DSD continues to generate and use reclaimed water within its facilities while improving the operational reliability of its water reclamation facilities. In 2017-18, we generated reclaimed water at an average rate of approximately 1,340 cubic metres per day for non-potable purposes. Our largest water reclamation facilities are located in the Ngong Ping Sewage Treatment Works and Shatin Sewage Treatment Works.
The Ngong Ping Sewage Treatment Works, operated since 2006, is the first tertiary sewage treatment plant in Hong Kong with reclaimed water treatment facility. Safe and odourless reclaimed water produced by this plant is now supplied to public toilets in Ngong Ping and the Ngong Ping Cable Car Terminal for flushing. Some of the reclaimed water is used for rearing ornamental fish in fish ponds and controlled irrigation within the sewage treatment works.
The water reclamation facilities in the Shatin Sewage Treatment Works, which were commissioned in early 2011, mainly comprising three filtration parts, namely disc filters, ultra-filtration membranes and reverse osmosis membranes, and are capable of generating 1,000 cubic metres of reclaimed water every day for plant cleaning, irrigation, toilet flushing and chemical dilution.