Question

State in brief, the preventive steps to control the pollution of water bodies in the locality. 

Answer 1

Preventive steps to -  Control pollution of water bodies in the locality

• Collection & Disposal of Domestic Sewage: A typical waste water system for sewage i.e. waste water generated from household activity consists of a network of waste water pipes.
  Sewer Lateral Pipe is the waste water pipe which collects sewage from household.
  Server Main Pipe is the larger pipe on the main street which connects from sewer lateral pipe.
  The waste water from the sewer main pipe is then led to the Water treatment plant.

• Water treatment plant: The waste water from sewer main pipe is then led to the water treatment plant.
  It consists of –
  Screen — Large waste materials such as leaves, rocks, twigs, etc. are easily removed.
  Coagulation – Coagulated suspended impurities are removed by adding coagulants [e.g. alum], which settle down and are removed before filtration of ‘water. Sedimentation – Solid suspended particles settle down in the sedimentation tank. Filtration – Remaining pollutants are removed by passing water through sand & gravel filters.
  Disinfection – Remaining pathogens are killed by liquid chlorine [ozone or bleaching powder]