In Hong Kong, 80% sewage is concentrated in the sewage treatment center. Sewage treatment is intended to remove contaminants from used water before it enters the waterways. Then the sewage is first passed through a series of screens that remove large objects, such as sticks, stones, rags and plastic bags. The sewage then enter a grit chamber where flow rate is slowed to settle out grit particles like coarse send and gravel. Then it is sent to the sedimentation tanks where the flow rate is further decreased to permit most of the suspended solids to settle out. This stage of treatment is known as primary treatment. The solids removed from the sewage are used as landfill.
Apart from that, Hong Kong also has the chemical waste treatment center (CWTC) to deal with the wide range of rapidly changing chemical wastes generated by the Hong Kong industry.
oil
/ water separation system ˇV recovering waste oil from oily water
mixture:
physicalˇVchemical treatment system ˇV treating water-based chemical
waste such as acids, alkalis, and wastewater containing heavy metal salts: and
high temperature chemical incinerator ˇV destroying the hazardous
organic waste such as pesticides and polychlorinated biphenyls, and cyanide
waste.
