Sewage water is generated from domestic, factories and agricultural activities. Domestic waste water is called as sewage
- waste water from gray-water or sullage is called
- waste water from toilet is called excreta or black- water
Sewage water consists of 99.3 to 99.7 % of liquidand 0.3 to 0.7% of solids state.
The solidsin the sewage water are of two types
- Organic solids
- Inorganic solids.
Organic solids are thederived from living things like produces from plant and . The organic solids undergo decomposition by the microorganisms.
Examples : carbohydrate, protein & fat.
Inorganic solids are inert materials that they do not undergo decomposition by the microorganisms and are inert fixed solids.
Examples: Grit, Salt, Chemicals, Metals etc.
These twoare mainly degradation of the environment if they are discharged into the environment as such.
If these solids are removed from the sewage water by Treatment process the water can be reclaimed and reused.