Page 128 - The Hong Kong Green Building Council (HKGBC) 香港綠色建築議會

Public Sector
Projects
Seawater is already available for toilet
flushing in metropolitan areas and most of
the new towns in Hong Kong, covering about
80 percent of the population. At present,
though, the North West New Territories
(NWNT), except Tuen Mun New Town, is
currently supplied with temporary mains
fresh (TMF) water for flushing. A review of
the flushing water supply in NWNT concluded
that it would be more cost-effective to use
salt water for flushing. The Water Supplies
Department (WSD) therefore proposed to
replace the current supply of TMF with a
salt water supply system in NWNT to save
precious fresh water and provide a more
economical flushing water source.
The project aims to provide a seawater
supply for toilet flushing in Tin Shui Wai, Yuen water closets to improve sanitary conditions.
Long Town, and the Yuen Long – Tuen Mun
Corridor, the eastern part of Tuen Mun New
Town and Tuen Mun East areas, all of which
are located in NWNT. The new salt water
supply system requires the construction of
a seafront salt water pumping station with
a capacity of 83 million litres per day at Lok
On Pai, a salt water service reservoir with
a size of 18,100 m3 at Tan Kwai Tsuen, an
intermediate booster chlorination plant at
Tuen Mun Water Treatment Works, and the
laying of approximately 16.8 kilometres of
associated salt water mains ranging from 300
to 1,000 mm in diameter.
126 HONG KONG REPORT ON THE STATE OF SUSTAINABLE BUILT ENVIRONMENT 2014
Salt Water Supply for
the North West New Territories
The construction works are being In 1955, the Government started its first
implemented under nine works contracts, pilot scheme to use seawater for toilet
with the first one commencing in October flushing, but this was not welcomed by flat
2008. The construction of the service reservoir owners at that time because of the high cost
commenced in January 2010 and was involved in retrofitting existing buildings.
substantially completed in November 2013, The atmosphere, however, changed in
while that of the pumping station commenced 1963-1964 when Hong Kong experienced its
in February 2010 for target completion in worst drought in history, with water supplied
August 2014. The overall construction works to the public for only four hours in every four
are expected to be completed by the end of days for a whole year, resulting in a serious
2014. After completion of the construction economic downturn. In the 1960s, new
works, conversion works will be conducted in legislation was passed requiring all newly
stages to introduce the salt water supply for built private buildings to be equipped with
toilet flushing. water flushing facilities, which included a
separate flushing system, drainage pipes for
The history of using seawater for toilet waste, toilets and flushing cisterns. Since
flushing in Hong Kong can be traced back to then, the percentage of coverage by the
the 1950s when Hong Kong started to use system has gradually increased.
PROJECT SCALE / USE The new salt water supply system under the project requires
Site area (approx.) the construction of a seafront salt water pumping station
Gross floor area (approx.) with capacity of 83MLD at Lok On Pai, a salt water service
Number of floor above grade reservoir with size of 18,100m3 at Tan Kwai Tsuen, an
intermediate booster chlorination plant at Tuen Mun Water
Approximate final population Treatment Works and laying of approximately 16.8km of
Key Occupancy type(s) associated salt water mains ranging from 300 to 1,000 mm
in diameter.
Estimated population of 696,000 will be served by the new
salt water supply system for toilet flushing
N/A