Biofiltration of concentrated mixtures of hydrogen sulfide and methanol

To date, little research has addressed biofiltration of volatile organic compound WOO and reduced sulfur compound (RSC) mixtures at the relatively high concentrations (0 to 450ppm(v)) of interest to the pulp and paper industry. The objectives of this study were to assess the impact of cotreatment on the biofiltration of air einissions containing mixtures of RSCs and VOCs, and to develop models of the processes. Experiments were conducted at various concentrations (16 s EBRT) using hydrogen sulfide as a model RSC (0-450 ppm(v)) and methanol as a model VOC (0-400 ppm(v)). Reaction-limited and biofilm models showed that hydrogen sulfide degradation followed Monod kinetics, while methanol removal was first order, The maximum hydrogen sulfide removal rate observed during the first three months of operation was 144 g H2S/m(3) bed/h. However, this declined to 85-95g H2S/m(3) bed/h in subsequent months. The methanol removal rate was 70-80% of the applied load (maximum 480g methanol/m(3) bed/h) for single component and mixture treatment. The results indicate that methanol and hydrogen sulfide removal in biofilters are independent and that co-troatment is an attractive option.