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Environmental Health - Toxic Substances



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Anaerobic Biodegradation


Anaerobic Biodegradation - "The degradation of compounds by microorganisms in the absence of oxygen." - National Research Council, 1994

Anaerobic Respiration - "The process whereby microorganisms use a chemical other than oxygen as an electron acceptor. Common 'substitutes' for oxygen are nitrate, sulfate, and iron." - National Research Council, 1993

Anaerobic Respiration - "In anaerobic respiration, nitrate (NO3-), sulfate (SO42-), metals such as iron (Fe3+) and manganese (Mn4+), or even CO2 can play the role of oxygen, accepting electrons from the degraded contaminant. Thus, anaerobic respiration uses inorganic chemicals as electron acceptors. In addition to new cell matter, the byproducts of anaerobic respiration may include nitrogen gas (N2), hydrogen sulfide (H2S), reduced forms of metals, and methane (CH4), depending on the electron acceptor." - National Research Council, 1993

Anaerobic Processes - “Anaerobic processes are used for treating wastewater with high concentrations of biodegradable organic materials, such as concentrated domestic wastewater, biosolids, animal manure slurry, and food processing wastes … The three biochemical reactions that characterize anaerobic processes are:
Hydrolysis- enzyme mediated transformation of complex organic compounds into simple compounds.
Acidogenesis- bacterial conversion of simple compounds into substrates for methanogenesis (acetate, formate, hydrogen, carbon dioxide).
Methanogenesis- bacterial conversion of methanogenic substrates into methane and carbon dioxide.” - Leverenz and others, 2002

Related Definitions




Aerobic Biodegradation

Electron Acceptor

Electron Donor




Natural Attenuation

USGS Information on Biodegradation

Related Headlines

Other Information on Biodegradation


Leverenz, H., Tchobanoglous, G., and Darby, J.L., 2002, Review of technologies for the onsite treatment of wastewater in California: University of California Davis, Center for Environmental and Water Resources Engineering 02-2. 

National Research Council, 1993, In situ bioremediation--When does it work?: Washington, D.C., National Academies Press, 224 p.

National Research Council, 1994, Alternatives for ground water cleanup: Washington, D.C., National Academies Press, 315 p.


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