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| ~Pollution Control~ | ||||
| Conservation | Legislation | Sewage Treatment | Education ~media ~awareness |
Birth Control |
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ewage |
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reatment |
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| Biological Principle of Sewage Treatment | ||
1. |
Sedimentation | |
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Sewage stands in large settlement tanks | |
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Solid substances settle down to form a sludge | |
2. |
Decomposition | |
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Liquid is pumped into oxidation pond and bubbled with compressed air inside the aeration tank | |
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Decomposers like putrefying bacteria and fungi in the sewage are active and oxidize organic compounds into inorganic compunds | |
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Liquid is then chlorinated to kill micro-organisms and filtered to remove large particles before discharge | |
3. |
Fermentation | |
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Solid sludge is passed from settling tank to the digestion chamber for fermentation by bacteria | |
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The anerobic process produces methane gas which can be used as fuel to drive the sewage treatment plant | |
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Remaning solid is dried and used as a fertilizer | |
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Sewage Treatment In Hong Kong |
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Stanley Sewage Treatment Works in a rock cavern. |
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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 |
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