Ibiam O. F. A and Igewnyi I.
Sewage is water-carried wastes, in either solution or suspension that flow away from a community. It is also known as waste water flows or used water supply of the community. Sewage management deals with various ways sewage could be treated to the advantage of man. The processes involve collection of the sewage, treating, screening and disposing them in a way that it will not pose any hazards to man environmentally or health wise. Treatment could be primary, secondary or tertiary. In primary treatment, sewage flows through large tanks, commonly called “primary clarifiers” or “primary sedimentation tanks”. The tanks are large enough that sludge can settle and floating material such as grease and oils can rise to the surface and be skimmed off. The main purpose of the primary treatment is to produce both a generally homogeneous liquid capable of being treated biologically and a sludge that can be separately treated or processed. Secondary treatment is designed to substantially degrade the biological content of the sewage such as are derived from human waste, food waste, soaps and detergent. The purpose of tertiary treatment is to provide a final treatment stage to raise the effluent quality before it is discharged to the receiving environment (sea, river, lake, ground, etc.). Screening involves straining to remove all large objects carried in the sewage stream, such as rags, sticks, tampons, cans, fruit, etc. This is most commonly done with an automated mechanically raked bar screen in modern plants serving large populations, whilst in smaller or less modern plants manually cleaned screen may be used. Details of other sewage management processes and benefits of this management are discussed in this paper
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