REMOVAL CHARACTERISTICS OF HYDROGEN-SULFIDE AND METHANETHIOL BY THIOBACILLUS SP ISOLATED FROM PEAT IN BIOLOGICAL DEODORIZATION

Thiobacillus sp. HA43 as a dominant strain was isolated from a H2S-acclimated peat biofilter seeded with aerobically-digested sludge oa night soil. Strain HA43 degraded both H2S and methanethiol (MT) without lagtime, but degraded neither dimethyl sulphide (DMS) nor dimethyl disulphide (DMDS). The removal characteristics for sulphur compounds (H2S, MT, DMS and DMDS) by strain HA43 well reflected the removal behaviour of the H2S-acclimated peat biofilter where this strain was isolated. The specific H2S and MT uptake rates of strain HA43 in batch culture were determined as 1.22 x 10(-12) and 8.53 x 10(-14) g-S.cell-1.h-1, respectively. The maximum removal rates (V(m) = g-S.kg-dry peat-1.d-1) for H2S and MT by peat biofilter inoculated by strain HA43 were obtained as follows: V(m)(H2S) = 11.3, V(m)(MT) = 0.21 in sterilized peat; V(m)(H2S) = 12.4, V(m)(MT) = 0.27 in non-sterilized peat; V(m)(H2S) = 33.0, V(m)(MT) = 0.27 in peat with aerobically-digested sludge of night soil. The peat biofilter inoculated with strain HA43 enhanced the maximum removal rate for H2S 6-fold compared with the biofilter without strain HA43.