A performance study of simultaneous microbial removal of no and SO2 in a biotrickling-filter under anaerobic condition

Abstract

-The behaviors of simultaneous removal of NO and SO 2 using the coculture of anaerobic denitrifying bacteria and sulfate reducing bacteria was investigated in a bench-scale biotrickling-filter. When the combined NO/SO 2 removal biotrickling-filter was operated at an empty bed residence time of 76 s with NO and SO 2 feed concentrations of 2 and 2 g/m 3 , respectively, the SO 2 removal efficiency was always above 95%, while NO removal exhibited an evident periodicity of 5-6 days for the initial 60 days after the attachment phase. A steady-state NO-removal efficiency of around 90% was obtained after 130 days of continuous operation. Experimental results indicated that the coculture in the combined NO/SO 2 removal biotrickling-filter showed a higher resistance to shock NO-loadings and a better tolerance to starvation than the single denitrifying bacteria in the NO removal biotrickling-filter.