Desulfurization performance of biotrickling filter on the removal of flue gas adsorbent produced by dual-alkali flue gas desulfurization process

A biotrickling filter (BTF) was used to investigate the elimination of flue gas adsorbent containing sulfite, sulfate, and hydrosulfate; it was undertaken to replace the regeneration step of dual-alkali flue gas desulfurization. Sulfate-reducing bacteria (SRB) isolated from landfill leachate were inoculated, and overall desulfurization performance as well as impact resistance was evaluated. The results showed that an efficient SRB could reduce the start-up time to 1 h, which is one third of that required for initial condition, for a sulfite removal efficiency above 80%. Further, the sulfite removal efficiency rose to 98% in 3.9 h with the lower packing load of 5.56 kg SO32--S/(m(3)d), and in 6.4 h for 6.37 kg SO32--S/(m(3)d). In contrast, 85% removal efficiency in 5 h for sulfate and 98% removal efficiency in 0.5 h for hydrosulfite were obtained when the packing loads were 0.95 kg SO42--S/(m(3)d) and 1.76 kg HSO3--S/(m(3)d), respectively. Moreover, the BTF could quickly restore after impact shock, such as, 0.5 h restoration time for initial pH which varied from 4.5 to 6.5, 6 d for 27 d shutdown behavior, and 4 d for 5 h high temperature shock of 85 degrees C. Therefore, the BTF system was an effective method for flue gas adsorbent treatment.