Desulfuration by colour less sulfur bacteria and sulfate-reducing bacteria under micro-aerobic condition
微氧环境下无色硫细菌和硫酸盐还原菌脱硫

Desulfuration of organic wastewater containing sulfate was realized by transforming the sulfate to elementary sulfur in a micro-aerobic condition resulted from intermittence aeration, in which sulfate-reducing bacteria (SRB) and colorless sulfur bacteria (CSB) kept symbiotic. The effect of oxygen amount on the reduction of SRB and oxidization of CSB was investigated. The optimal aeration intensity and hydraulic retention time under which the maximum ratio of elementary sulfur to the amount of total sulfur occurred were found. The results indicated that, for an influent with COD/SO42-=2 000/1 500 mg/L, after being processed in such a system with the aeration switching time of 2 s/2 min and biochemical time of 10 h, the maximum productivity of elemental sulfur of 89.53% was achieved, with the minimum sulfate concentration of 72.7 mg/L, and a sulfate reduction rate of 95.1%.