Low H2S 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 H2S 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 H2S removal and oxygen utilization. The results show that the sulfur loading rate decreased by 66% compared to conventional H2S content, thus achieving a sufficient removal efficiency (>0.9). With a limited external aeration (0.5-2.0 molO2·molS-1), the oxygen consumption (O/Sre) to its supplement (O/Sin) ratios increased from 50-71% (conventional H2S) to 83-92% (low H2S), indicating that low H2S 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 H2S 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.