A large amount of organic material must be eliminated through the wastewater treatment process. Anaerobic digestion is commonly used in the United States to decompose the organic material found in raw wastewater. Anaerobic digestion is an important process that is conducted in an oxygen-free environment and can greatly reduce the amount of organic matter that might be dumped at sea, in landfills or burned in incinerators.
One organism, Archaea, is used to improve treatment plant performance. Archaea are single-celled organisms that are classified wholly separate from bacteria. They are considered to be extremophiles because Archaea can tolerate very harsh environmental conditions. For example, Archaea have been found in hot springs and salt lakes where no other living organisms can survive. But these organisms are ubiquitous and have been identified in many soil types, oceans, marshlands, swamps and the human colon.
Some of the best known Archaea are methanogens. These organisms produce methane gas and carbon dioxide as by-products during the anaerobic digestion of organic matter. Both methane and carbon dioxide are biogases and can be captured as a renewable source of energy. The use of methanogens in anaerobic digestion decreases the production of toxic hydrogen sulfide gas. Methanogens can also significantly reduce the amount of sludge that is wasted at a wastewater treatment plant. Reducing wasted sludge is good for the environment and good for the bottom line.