In 2004, we continued to face
with the challenges of increasing volume of sewage to our sewage
treatment works in which some have already been overloaded, and we have
committed to improve our service delivery to meet the ever higher demand
of the public on environmental quality. We took a two-pronged approach of
maintaining a lively dialogue with the stakeholders to understand their
concerns and explain our work, and exploring the latest proven technology
to address the specific local environmental issues. A few examples of how
we addressed the issues are given below.
Overloading
of Sewage Treatment Works
We tackled the problem of sewage overloading by a long term solution of extending
the capacity of our sewage treatment works. In the interim, we modified the treatment processes
and made extra effort to monitor the processes to achieve the effluent
quality standards. In 2004,
the Stage 3 Phase 1 of the Shatin Sewage Treatment Works was commissioned
successfully and the treatment capacity was increased from 148,000 to
216,000 m3/day. The treatment capacity will further be
increased to 318,000 m3/day upon the successful commissioning
of the Phase 2 of the project in 2005. The extension of the Tai Po Sewage
Treatment Works and Shek Wu Hui Sewage Treatment Works were in
satisfactory progress.
On
process modification, we have been upgrading the Siu Ho Wan Treatment
Works to Chemically Enhanced Primary Treatment with UV disinfection to
remove BOD and disinfect the effluent, modifying two primary
sedimentation tanks at Shek Wu Hui Sewage Treatment Works to Sequencing
Batch Reactors to reduce the nitrogen loading to the aeration tanks, and
converting some aeration tanks of the activated sludge treatment process
at the Yuen Long Sewage Treatment Works to be operated as extended
aeration process to reduce sludge production.
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Siu Ho Wan Sewage
Treatment Works
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Shatin STW
aeration tank
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Shatin STW
sedimentation tank
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Odour Control
Odour is a common problem of sewage and sewerage. The extension of the
sewage treatment works and the process modification and upgrading
mentioned above help alleviate the problem. In addition, we added ferric
chloride to precipitate the odour causing agent, sulfide; and added
calcium nitrate to prevent its production in the sewerage handling septic
sewage.
Sewerage Works
in Urban Area
Construction and replacement of sewers in busy urban areas pose a unique
challenge to us. We have to strike a balance between the disruption to
traffic and the impact on the environment. We need to restrict the work site area and shorten the
work duration on one hand, and put in more pollution control equipment on
site and limit our working hours on the other hand. In addition to reduce road
openings to a minimum, we have to implement stringent environmental
control on site to properly manage dust, odour, noise and muddy
discharge. Furthermore, we also set up communication channels to
neighbours so that their grievances can be attended to and resolved
immediately.
Works in Java Road near North Point Pier
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Works in shopping district Causeway Bay
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