In Situ Bioremediation of Groundwater
Bioremediation is a technology which modifies physical, chemical, biochemical, or microbiological environmental conditions to help them destroy or detoxify organic and inorganic matter in various environmental media. The process works above ground, underground, and in materials or water. Indigenous bacterial groups are helped by stimulating them (biostimulation) through various amendments or certain subgroups which are introduced (bioaugmentation) to treat hazardous materials or waste, to make them less hazardous or non-hazardous. A variety of amendments may be added depending on the contaminant, but the problem appears to be the distribution of the amendments in order to clean up and remove the contaminant.
Aerobic bioremediation effectively treats non-halogenated organic compounds. Additional oxygen can be added to help move the process forward more rapidly. Anaerobic oxidative bioremediation uses electron receptors such as nitrates or sulfates for the microbial metabolic oxidation of the substance. It works well on halogenated organic compounds, especially chlorinated solvents. Hexavalent chromium is reduced to trivalent chromium.
Cometabolism is a process where microorganisms use a compound as an energy source while also producing an enzyme that can chemically transform another compound. The microorganisms can then degrade certain contaminants. This is particularly effective in low contaminant concentrations.