화학공학소재연구정보센터
Biotechnology and Bioengineering, Vol.110, No.12, 3139-3147, 2013
Perchlorate Reduction From a Highly Contaminated Groundwater in the Presence of Sulfate-Reducing Bacteria in a Hydrogen-Fed Biofilm
We used a hydrogen (H-2)-based biofilm to treat a groundwater contaminated with perchlorate (ClO4-) at approximate to 10mg/L, an unusually high concentration. To enhance ClO4- removal, we either increased the H-2 pressure or decreased the electron-acceptor surface loading. The ClO4- removal increased from 94% to 98% when the H-2 pressure was increased from 1.3 to 1.7atm when the total acceptor surface loading was 0.49gH(2)/m(2)day. We then decreased the acceptor surface loading stepwise from 0.49 to 0.07gH(2)/m(2)day, and the ClO4- removal improved to 99.6%, giving an effluent ClO4- concentration of 41 mu g/L. However, the tradeoff was that sulfate (SO42-) reduction occurred, reaching 85% conversion at the lowest acceptor surface loading (0.07gH(2)/m(2)day). In two steady states with the highest ClO4- reduction, we assayed for the presence of perchlorate-reducing bacteria (PRB), denitrifying bacteria (DB), and sulfate-reducing bacteria (SRB) by quantitative polymerase chain reaction (qPCR) targeting characteristic reductases. The qPCR results documented competition between PRB and SRB for space within the biofilm. A simple model analysis for a steady-state biofilm suggests that competition from SRB pushed the PRB to locations having a higher detachment rate, which prevented them from driving the ClO4- concentration below 41 mu g/L. Biotechnol. Bioeng. 2013;110: 3139-3147. (c) 2013 Wiley Periodicals, Inc.