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Field Tests of “In-Situ” Remediation of Groundwater From Dissolved Mercury Utilizing Sulfate Reducing Bacteria
Citation:
Abdrashitova, S., W. Davis-Hoover, R. Devereux, G. Uskov, N. Zyryanova, M. Ilyushchenko, AND L. Yakovleva. Field Tests of “In-Situ” Remediation of Groundwater From Dissolved Mercury Utilizing Sulfate Reducing Bacteria. Presented at The VII International Scientific Practical Conference Heavy Metals and Radionuclides in the Environment, October 04 - 08, 2012.
Impact/Purpose:
Describe field trials of a biological treatment to remove Hg from the flow of contaminated ground water. The results showed Hg concentrations were lowered substantially in the ground water and the process presents a viable option for mitigating Hg contamination.
Description:
Field tests of biologically active filters have been conducted at groundwater mercury pollution site in Pavlodar, Kazakhstan. The biofilters represented cultures of sulfate-reducing bacteria (SRB) immobilized on claydite imbedded in wells drilled down to basalt clay layer (14-17 m) underlying the groundwater. There was a set of contiguous wells arranged in line perpendicular to the groundwater flow. Total mercury and methyl mercury as well as other environmental parameters were measured in the groundwater twice per month up- and downstream of the set of the treatment wells. In order to estimate removal of mercury and its breakthrough monitoring of the wells was carried out for 10 months. The field tests with SRB immobilized on claydite showed that for all period of the trials concentration of total mercury in outflow water decreased from 200 to 2 maximum permissible concentration (MPC) and concentration of methyl mercury was about 2-4 MPC. In a control cluster of wells in a treatment well of which SRB and acetate as a nutrient for their growth had not been introduced indigenous micro flora developed with generation of significant amount of methyl mercury. Field tests with anaerobic SRB capable of utilizing acetate and immobilized on claydite proved their potentiality to be used for groundwater cleanup from mercury with minimal generation of methyl mercury. This way of mercury contaminated groundwater remediation is cost-effective one and does not require expensive technologies. At the same time it would be expedient to carry out longer monitoring research of the process of groundwater remediation from dissolved mercury for assessment of possible risks