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physical treatment of municipal and industrial wastes. It is useful in the following
ways:
➢ It can be used as a fertilizer or as landfill.
➢ Sewage sludge and wastewater effluents can provide essential plant nutrients
and water. Since sludge is rich in organic matter, it can improve the physical
condition of the soil.
There are three types of sewers:
• Foul or sanitary sewers carry wastewater from our homes into wastewater
treatment plants.
• Storm sewers carry rainwater from the roof and roads into streams and rivers.
• Combined sewers carry both wastewater and surface water to wastewater
treatment plant.
Constituents of sewage-
• Organic impurities
• Inorganic impurities
• Nutrients
• Diseases causing microbes
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