2.7.Pollutants

Unit 2 : Sewage and domestic wastes, treatment and reuse

2.7.Pollutants
There are two categories of pollutants
  • Dissolved solids and liquids
  • Suspended solids and liquids
Most of the chemicals released in the effluents are generally soluble in water. They form aqueous solutions and therefore, cannot be separated by ordinary physical processes like screening, settling and filtration.

Dissolved solids and liquids are removed from the wastes following one of the following methods.
  • Neutralization
  • Oxidation
  • Reduction
  • Reverse osmosis
  • Ion-exchange
  • Carbon adsorption
  • Phenol destruction
  • Evaporative stripping.
The suspended solids and liquids are removed by
  • Filtration
  • Sedimentation
  • Floatation
  • Flocculation
  • Centrifugation
  • Incineration
  • Oil- water separation
Last modified: Thursday, 9 June 2011, 12:00 PM