Low H 2 S content biogas biodesulfurization from high solid sludge anaerobic digestion using limited external aeration biotrickling filter: Effect of gas-liquid pattern on oxygen utilization performance

An efficient and precise method is needed for low H S content biogas biodesulfurization, produced during high solid sludge anaerobic digestion. Continuous experiments were conducted to evaluate the performance of a lab-scale biotrickling filter (BTF) in H S removal and oxygen utilization. The results show that the sulfur loading rate decreased by 66% compared to conventional H S content, thus achieving a sufficient removal efficiency (>0.9). With a limited external aeration (0.5-2.0 molO ·molS ), the oxygen consumption (O/S ) to its supplement (O/S ) ratios increased from 50-71% (conventional H S) to 83-92% (low H S), indicating that low H S flux promotes a sufficient oxygen utilization. Furthermore, the difference in oxygen utilization between co-current and counter-current flow patterns decreased under limited external aeration as the H S content sharply decreased. These results indicate that a dynamic oxygen-sulfur (O-S) balanced multistage BTF is expected to achieve a more precise vertical O-S distribution for sulfur resource recovery.