Dimethyl Sulfide Removal Using Biofilter Immobilized Thiobacillus sp. ST22

A biofilter packed with immobilized Thiobacillus sp. ST22 was investigated for the treatment of gases containing dimethyl sulfide (DMS). Thiobacillus sp. ST22 was immobilized using a sodium alginate, polyvinyl alcohol and powdered activated carbon as entrapping materials. The experimental results showed that the removal of DMS achieved an efficiency of 99.5%. The optimal spray density and empty bed residence time (EBRT) were 0.17 m(3) center dot m(-2) center dot h(-1) and 21 s, respectively. Bacterial communities in the biofilter were assessed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE), which plays a dominant role in the biological processes of simultaneous sulfur oxidation and sulfate reduction. The results showed that Thiobacillus sp. ST22, delta proteobacterium were the predominant bacteria. Dimethyl sulfide can be oxidized into H2SO4, CO2 by Thiobacillus sp. ST22 biooxidation in the outer zones of immobilized cell beads due to aerobic conditions. Dimethyl sulfide can be degradated into S2-, CH3OH, and HCOOH; H2SO4 can be reduced to SO32-, S-0, and S2- by delta proteobacterium and Acidobacteria bacterium using CH3OH and HCOOH as the electron donors in the inner zones of immobilized cell beads due to anoxic conditions. (C) 2014 American Society of Civil Engineers.