A performance Study of Simultaneous Microbial Removal of NO and SO2 in a Biotrickling-Filter Under Anaerobic Condition

Behaviors of simultaneous removal of NO and SO2 using the coculture of anaerobic denitrifying bacteria and sulfate reducing bacteria were investigated in a bench-scale biotrickling-filter. Approximate 20 days were required to use the landfill leachate as the microbial seed to develop the biofilm on the surface of packing material. When the combined NO/SO2 removal biotrickling-filter was operated at an empty bed residence time (EBRT) of 76 s and the NO and SO2 feed concentrations of 2 and 2 g/m3 respectively, the SO2 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 and then a steady-state NO-removal efficiency of around 90% was obtained after 130 days of continuous operation. Contrast experimental results indicated that the coculture in the combined NO/SO2 removal biotrickling-filter showed a higher resistance to shock NO-loadings and a better tolerance of starvation than the single denitrifying bacteria in the NO removal biotrickling-filter.