What microorganisms are in sewage treatment?
Bacteria. Sewage consists of domestic and industrial waste and sometimes drainage from rainfall. First the sewage passes through screens to removal the larger soilds, and passes into a settlement tank. After this the liquid component and sludge are treated separately. Aerobic bacteria digest, breakdown and oxidise organic components of the liquid component in oxidation ponds(liquid trickled from a rotating arm over stons with bacteria on them) OR an activated sludge tank(airbubbled through bacteria and sludge). This is because these bacteria need oxygen for repiration/metabolism to break down the sludge efficiently. The digestion of more soild sludge is carried out by anaerobic bacteria in tanks, producing a mixture of carbon dioxide and methane. THe digested sludge may be used as compost/fertiliser to grow plants. The methane can be used as fuel source at the sewage treatment plant to heat the plant or to produce electricity. Sewage treatment reduces the organic content and suspended
