WSD has been actively exploring the use of recycled water (viz. reclaimed water, treated grey water and harvested rainwater) by providing a centralized recycled water supply system in those areas where fresh water is being used for flushing and in new development areas especially in the inland areas to contain the fresh water demand. The use of recycled water also minimises impacts to the environment by reducing the amount of treated sewage effluent discharged to the receiving water.
Reclaimed water is a water resource generated by further processing treated effluent from sewage treatment works. Pilot schemes involving the use of reclaimed water began in Hong Kong in 2006. The Government has commissioned the first pilot scheme at Ngong Ping to provide reclaimed water, by converting the treated effluent from sewage treatment works, for non-potable uses.
Under the Total Water Management Strategy, we will expand the use of lower grade water (including recycled water) for flushing and other non-potable purposes to save fresh water resources. We continue our works to supply reclaimed water, converted from tertiary treated sewage effluent at the Shek Wu Hui Effluent Polishing Plant, to the north-eastern part of the New Territories for non-potable uses starting with Sheung Shui and Fanling in phases. The supply of reclaimed water is estimated to save Hong Kong about 22 million cubic metres of fresh water each year.
The production cost for reclaimed water is estimated to be $7.3 per cubic metres.
(The above production cost is based on the preliminary design for reclaimed water being planned for Sheung Shui and Fanling and does not include the sewage treatment cost. However, the quality of treated sewage effluent would affect the production cost of reclaimed water.)
Water collected from baths, showers, wash basins, kitchen sinks and laundry machines etc. is known as grey water. Along with harvested rainwater, the grey water can be treated and reused for non-potable purposes such as toilet flushing.
We have formulated guidelines on the implementation of rainwater harvesting and grey water recycling systems to facilitate new government buildings to install on-site treatment and recycling facilities. The guidelines have been incorporated in the joint Development Bureau and Environment Bureau Technical Circular on Green Government Buildings issued in April 2015.
WSD is constructing a centralized grey water recycling system treating grey water collected from inhabitants at the Anderson Road Quarry development site for flushing use. The system consists of a grey water treatment plant with associated pumping system, a service reservoir, pipes for grey water collection and the distribution of the treated grey water to consumers.
Technical Specifications on Grey Water Reuse and Rainwater Harvesting 1st Edition
[Note: Water quality standard of the recycled grey water and harvested rainwater to be used for non-potable purposes can be made reference to the above document.]
[Friendly Reminder: In face of the current situation of Novel Coronavirus (Covid-19), users are reminded to strictly adhere to the Technical Specifications.]