Anerobic digestion is very pratical method of reducing waste and creating energy. Many wastewater treatment plants have incorporated this process to efficiently reduce the volume of sludge produced by the plant and the number of pathogens it contains. The methane gas that is produce from the process is used to heat the digestor for optium gas production and waste reduction. However, the excess gas is usually used to produce electricity, but it can also supplement natural gas after being scrubbed of impurities. Once gas production has stopped in the digestor, the treated sludge can be dryed and used as fertilizer. There are regulations that govern land application of treated sludge or biosolids which require additional treatment of the biosolids to further reduce pathogen concentrations.
In the developing world, very humble anerobic digesters are utilized on small scales by people for waste management. The methane produced is then used for heating, cooking, and lighting.