Agriculture wastewater however can be treated by using biological processes in which the activity of microorganisms such as bacteria, algae, fungi, plants and animals is involved. This approach is followed in various parts of the world.
The water treatment system consist of biodigester and aquatic plant channels. When the wastewater passes through the biodigester the pollutants and microorganism are transformed into biogas, aquatic plant biomass etc. The Biochemical Oxygen Demand (BOD) and suspended solids are reduced to a considerable level in this system.
Apart from this membrane bioreactor and tertiary filtration systems can also be used for treating wastewater. The product water is of good quality and can be used for crop irrigation. Irrigation with treated wastewater produces higher yields than crops irrigated with fresh water.