Removability of malodorous gases from a night soil treatment plant by a pilot-scale peat biofilter inoculated with thiobacillus thioparus DW44

Abstract

Thiobacillus thioparus DW44, which degrades hydrogen sulfide (H 2S), methanethiol (MT), dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) was inoculated into a pilot-scale peat biofilter installed in a night soil treatment plant. These gases emitted from the plant were treated at various space velocities(SV) from 46 to 500 h −1. The removal ratios for the gases were more than 95% up to a SV of 300 h −1 if pH was properly controlled. At SV 500 h −1, a rapid decline in pH reduced the removal activity by DW44, mainly due to a decrease in the number of DW44 cells in the peat. The permissible inlet sulfur loads of peat inoculated with DW44 for H 2S, MT, DMS and DMDS were determined to be around 2.0, 0.07, 0.03 and 0.004 g-S-kg-dry peat −1.d −1, respectively.