Chlorinated solvents and Hexavalent chromium are known to be toxics and carcinogens. Industrial accidents, leakages in pipes or storage tanks, and improper handling of these compounds have lead to the contamination of subsurface soil and groundwater. Bioremediation is one of the recent popular low cost technologies that can be effectively applied to remediate the soil and groundwater contaminated with these toxics. In nature there are several microbes which are capable of detoxifying and degrading the toxic chemicals. Usually, microbes use these contaminants to obtain energy, nutrients or for respiration. During these processes the contaminants are degraded to less toxic or nontoxic end products.
In this type of bioremediation the degradation capacity of microbes, indigenous to contaminated site, is exploited. Usually appropriate nutrients are applied to the contaminated sites to stimulate the population of microbes. We practice biostimulation by applying appropriate nutrients to the sites contaminated with Chlorinated solvents and Hexavalent chromium.
If the indigenous population of microbes is not capable of fully degrading the contaminants, external source of super microbes are applied to the contaminated media along with the nutrients. These externally added microbes multiply and increase in population while degrading the contaminants and using the added nutrients.