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|Biological Principle of Sewage Treatment|
|Sewage stands in large settlement tanks|
|Solid substances settle down to form a sludge|
|Liquid is pumped into oxidation pond and bubbled with compressed air inside the aeration tank|
|Decomposers like putrefying bacteria and fungi in the sewage are active and oxidize organic compounds into inorganic compunds|
|Liquid is then chlorinated to kill micro-organisms and filtered to remove large particles before discharge|
|Solid sludge is passed from settling tank to the digestion chamber for fermentation by bacteria|
|The anerobic process produces methane gas which can be used as fuel to drive the sewage treatment plant|
|Remaning solid is dried and used as a fertilizer|
Sewage Treatment In Hong Kong
Stanley Sewage Treatment Works in a rock cavern.
|The Tsing Yi
Chemical Waste Treatment Facility
- this centre is capable of treating the wide variety of chemical waste generated in Hong Kong. Operation started in May 1993