Question

While testing the field conditions at a prospective bioremediation site you discover that the soil is well oxygenated, contains sufficient nutrients to support the process, but there are no native microorganisms present that can break down the contaminant. What strategy or strategies would you pick to make your in situ bioremediation effective? (mark all that apply) Bioattenuation Bioaugmentation Biostimulation

Answer 1

Ans: The three main strategies used in in situ bioremediation are Bioattenuation, Biostimulation and Bioaugmentation.

Bioremediation is defined as a process, which relies on biological mechanisms to reduce (degrade, detoxify, mineralize or transform) concentration of pollutants to an innocuous state. The process of pollutant removal depends primarily on the nature of the pollutant, which may include: agrochemicals, chlorinated compounds, dyes, greenhouse gases, heavy metals, hydrocarbons, nuclear waste, plastics, and sewage. According to the site of application, bioremediation techniques can be categorized as: ex situ or in situ. The treatment of contaminated soil in the location where it was found can be considered as in situ bioremediation. The three main strategies used in in situ bioremediation are Bioattenuation, Biostimulation and Bioaugmentation.

Bioattenuation - This is a process in which biodegradation occurs naturally without human intervention. It includes a variety of chemical, physical and biological processes that reduce the mass, toxicity, volume or concentration of contaminants.

Biostimulation - It is one of the most mature methods of bioremediation of hydrocarbons. Biostimulation refers to the addition of rate limiting nutrients like phosphorus, nitrogen, oxygen, electron donors and carbon (in the form of molasses) to severely polluted sites to stimulate the existing bacteria to degrade the hazardous and toxic contaminants.

Bioaugmentation is the practice of adding cultured microorganisms into the subsurface for the purpose of biodegrading specific soil and groundwater contaminants.