sewage treatment

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sewage treatment

the treatment of raw sewage to make it harmless for discharge into rivers, seas and oceans. Treatment systems may involve
  1. (a) Primary treatment in which physical methods are used to remove solid matter (primary sludge) from the waste-water.
  2. (b) Secondary treatment in which biological methods, involving a range of aerobic bacteria, are used to degrade the organic matter in the waste-water. The treated sewage may then be disinfected before discharge from the sewage plant. The sludge that accumulates during both primary and secondary treatments is acted on by anaerobic bacteria in an anaerobic sludge digester. The methane produced can be used as a fuel for heating the digester, whilst the treated sludge is dried and may be used as a fertilizer.
  3. (c) Tertiary treatment in which chemical and physical methods are generally used to remove all the biochemical oxygen demand (BOD), nitrogen and phosphorus. After this treatment the water is disinfected and can be pumped direct into reservoirs. However, tertiary treatment is an expensive process, so water is often returned to the environment after secondary treatment.
References in periodicals archive ?
DEQ learned in March that the company had continued performing sewage disposal service with a suspended license, he said.
The ever-increasing populations in villages has meant more houses being built and no sewage disposal system in place, he said.
55 billion sewage disposal plant in Jebel Ali will be ready in August.
He said sewage disposal in the lake is stopped when rain forecasts are issued by the Presidency of Meteorology and Environment.
Phase 2 will determine what type of sewage disposal systems would be appropriate for the soils in those areas of town," he added.
The following summary provides you with some of the most frequently asked questions, along with the answers, about subsurface sewage disposal systems.
Each year, unsafe sewage disposal and fecal--oral transmission of pathogens are responsible for 3.
Further problems of a different nature arose as the new factories and the cities they were located in expanded: industrial wastes and sewage disposal from thousands of people.
Other tangible property (not including a building or its structural components), but only if such property "is used as an integral part of manufacturing, production, or extraction, or of furnishing transportation, communications, electrical energy, gas, water, or sewage disposal services.
BEG is active in waste and sewage disposal and is currently under sole control of the City of Bremerhaven.
The site also boasts a flourishing organic garden, demonstrations of innovative composting combinations and ecological sewage disposal methods.
will be capitalized at 40 million yen, equally split between Mitsubishi and Japan Hels Industry, a Tokyo-based company engaging in sewage disposal.