In Hong Kong, separate systems are provided for the collection and disposal of stormwater and sewage.
Over the past thirty years, the population in Hong Kong has increased significantly and the commercial and industrial activities have also grown dramatically. This has led to an increase in water consumption and a consequential increase in the quantity of wastewater to be handled. Today, our community generates 2 million tonnes of wastewater daily which requires proper collection, treatment and disposal.
In Hong Kong, sewers have been installed incrementally over the past century as development has progressed.
In 1971, a consultancy was commissioned “to investigate the state of the waters of Hong Kong and to recommend a programme of improvement works”. The recommendations of this study have since formed the blue print for the sewage treatment and disposal strategy which is to fully utilize the natural assimilative capacity of the sea. In the past, this strategy together with ad hoc additions to the sewerage system had been successful in mitigating serious deterioration of most of Hong Kong’s waters.
However, in the 1980’s, it was recognised that these sewerage arrangements were not adequate to contain the increasing threat of pollution. The White Paper “Pollution in Hong Kong – A Time to Act” of 1989 assessed the adequacy of current programmes and outlined a comprehensive plan to tackle pollution. This was complemented by the control of wastewater discharges through the Water Pollution Control Ordinance. A new sewage strategy has then been formulated and the following actions are now in hand to reduce the water pollution problem
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Continued implementation of “existing schemes” which have been in the public works programme and which are compatible with other proposed new measures to satisfy new water quality standards. Examples are new and improved sewage treatment and disposal facilities in the North West Kowloon, Tsuen Wan/Kwai Chung and the North West New Territories.
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In order to identify specific sewerage problems in various districts of Hong Kong and to propose improvements to the sewerage system, a series of “Sewerage Master Plans” (SMP) have been or are being prepared. As resources permit, the recommendations of SMP will be implemented in a prioritised manner which will greatly improve the effectiveness of the sewerage system.
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To improve the arrangements for sewage disposal, a “Strategic Sewage Disposal Scheme (SSDS)” combining elements of land based sewage treatment with the natural self-purification capacity of the ocean has been endorsed. It
consists of a deep tunnel system to collect all sewage in the most densely populated urban areas and to convey it to one of the two centralised sewage treatment plants (at Stonecutters Island and Mount Davis) for treatment.