Sewage treatment begins with the separation of large solids and debris. Water is then left in tanks so that large particle will settle at the bottom and grease will rise to the top. Three methods are availiable to take the clarified wastewater and mix it with microorganisms that eat the pollutants in the wastewater. Chemicals are added to balance out phosphorus and/or nitrogen. Chlorine and/or ultraviolet light are used to kill disease-causing organisms and disinfect.
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