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.