2008 Volume 49 Issue 10 Pages 2275-2282
Permeable reactive barriers (PRBs) column tests were performed to investigate the contribution of anaerobic microbial community in sheep manure on the removal of As from groundwater. The column was packed with zero valent iron (ZVI), sheep manure, compost, wood chips, glass beads and gravels. All materials were sterilized except for sheep manure that contains anaerobic bacteria. Decrease in sulfate concentration was observed at the maximum rate of 0.26 mmol dm−3 day−1. In addition, the sulfur isotopic ratio of δ34S increased from the influent (−4.3\\ extperthousand) to the effluent (0.2\\ extperthousand), suggesting that there was sulfate-reducing activity in the microbial community. Arsenate was more effectively immobilized on ZVI than arsenite. Bacterial community analysis using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) on 16S rRNA sequences suggested that majorities of bacteria were several Clostridium species and one species of Proteobacteria, Geobacter metallireducens GS-15, independently of PRBs column heights. Some of them might have contributed to the removal of arsenic.