Explain why some times foaming is seen in never water near the place where sewage water is poured after treatment?


 

Detergents have long hydrocarbon chains. If their hydrocarbon chain is highly branched, then bacteria cannot degrade this easily. Such detergents are non-biodegradable. The slow degradation of detergents leads to their accumulation.

Those non-biodegradable detergents persist in water even after sewage treatment and cause foaming in rivers, ponds, and their water gets polluted. In order to overcome this issue branching of the hydrocarbon chain is controlled and kept to a minimum.