Question

What bioremediation strategy was employed at the Old Rifle mill site? Biostimulation Bioaugmentation Bioattenuation

Answer 1

Ans:

The answer is 'Biostimulation'.

Explanation:

Bioremediation is the process of using microbial metabolism in the presence of optimal environmental conditions and sufficient nutrition to breakdown the contaminants such petroleum hydrocarbons,typically used to treat contaminated media,including soil,water and other subsurface material.

Biostimulation refers to the bioremediation process where limiting nutrients are used to support microbial growth,whereas Bioaugmentation refers to the bioremediation process in which living cells that are capable of degradation is used.There is a third type of bioremediation process which is usedd for pesticide contaminated soil,where the biodegradation occurs naturally and without any human intervention and is called as Bioattenuation.

The Old Rifle site which is located at a former uranium ore-processing facility in Rifle,Colo. is now a part of Uranium Mill Tailings Remedial Action program initiated by the U.S.Department of Energy.The department continuously faces the challenge of cleaning up and monitoring large and dilute plumes that are contaminated by harmful metals such as Uranium and Chromium.When they experimented with Biostimulation process,using acetate as the electron donor,they found that the metal reducing bacteria were able to efficiently remove Uranium from the groundwater,which was stimulated by nothing else but the electron donar acetate.When the aquifer was injected with acetate,it is was found to stimulate the growth of Geobacteraceae,Fe(III) reduction and a decline in the Uranium(VI) content of the groundwater,down gradient of the injection site.The whole experiment helped in concluding that maintaining a Fe(III) reducing condition is important for the sustaining reductive precipitation of Uranium and highlighted the importance to correlate Uranium removal from the groundwater with the alterations in the composition of subsurface that helped the microbial community.