08-12-2012, 02:23 PM
ANAEROBIC MICROBIAL DEGRADATION OF SURFACTANTS
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ABSTRACT
Surfactants which are used today constitute a diverse group of chemicals designed for cleaning and solubilization
purposes. These are the main ingredients of household and industrial detergents and are also used in personal care
products and in pesticide formulations. After use, surfactants can be found together with pollutants in waste water
that is treated in waste water treatment plants (WWTP) or are discharged directly into the aquatic environment. The
removal of surfactants from wastewater is a microbial process,
which has several advantages when compared to the
nonbiological techniques. Surfactants biodegradation in the
presence of oxygen is feasible and subject of many studies.
However, environments where molecular oxygen is present at very
low concentrations or is even absent are common in Nature.
Anoxic environments are found in anaerobic digesters, septic
tanks, organically enriched sediments, flooded soils and landfills.
Surfactants can be used as energy and carbon source by bacteria
where nitrate is present as an electron acceptor, if oxygen is
limiting or not available. Through the denitrification process, the
undesired accumulation of nitrate, in the WWTP or in the
environment, is avoided by its reduction to N2. The surfactant is
used as carbon source, being oxidized to CO2 and H2O (Figure 1).