Question

What are the various constituents of domestic sewage? Discuss the effect of sewage discharge in a river.

Answer 1

Domestic sewage is the waste water(sewage) discharged from residential areas. It consists of various constituents such as

• Dissolved materials in the form of both organic and inorganic compounds like toxic metal ions, nitrates, ammonia etc.
• Colloidal particles also in both organic and inorganic forms like fecal matter, paper, cloth fibers, bacteria etc.
• Suspended impurities mainly consist of sand and clay.

Being rich in biodegradable or organic matter, domestic sewage stimulates microbial growth for the decomposition process to occur. This increases Biochemical oxygen demand of water and stimulating mineral pollution or eutrophication. It imparts bad color and odor to the water body and also paves way for waterborne diseases.