Wastewater Treatment Essay Research Paper Wastewater TreatmentSciTeksJ — страница 2

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some type of porous medium. A sticky film of microorganisms coats the medium and acts as the removal agent. The organic matter in the waste stream is absorbed by the film and changed to carbon dioxide and water. If the trickling filter step comes before the sedimentation stage it can remove about 85 percent of the BOD entering the plant. 2) Activated Sludge This stage is an aerobic process that adds sticky sludge particles that have millions of of actively growing bacteria stuck together by a gelatinous slime. Organic matter is assimilated by the floc and changed to aerobic output. The reduction of BOD varies between 60 to 85 percent. 3) Stabilization Pond or Lagoon Another way of biological treatment is the the stabilization pond or lagoon. Facultative lagoons are the most

common, being 2 to 5 ft deep, with a surface area of several acres. Anaerobic conditions succeed in the bottom area, where the solids are decomposed. The area near the surface is aerobic, allowing the oxidation of dissolved and homogenous mixture of organic matter. A decrease in BOD of 75 to 85 percent can be accomplished. There are many other ways and stages of wastewater treatment but these are the basic processes. I learned alot about wastewater treatment and the it is a good thing we have it so the lakes and streams are no as dirty. 1) Waterlink Industries. 2000. ?Wastewater Treatment.? Science (Refreshed Daily): 6pp.Online. Internet. May 01, 2000. Available www.waterlink.com 2) Microsoft Encarta Encyclopedia 99 (1999). [Cd Rom computer program]. Redmond, WA: Microsoft