Biological removal of gas-phase H2S in hollow fibre membrane bioreactors

BACKGROUND: Hydrogen sulphide (H2S) must be treated at its emission source to avoid health risks, odour, and corrosion. Conventional physico-chemical H2S removal technologies (for example, membrane contactors or chemical scrubbers) have several limitations, such as requiring high amounts of absorption chemicals and energy. In contrast, biological H2S removal technologies are environment friendly, easy to operate, and less expensive due to their low energy requirements. In this study, the feasibility of a porous hydrophilic polyethersulfone hollow fibre membrane bioreactor (HFMB) was tested for the biological removal of gas-phase H2S by employing three lab-scale reactors (two biotic and one abiotic). The HFMBs were operated at similar to 20 degrees C for similar to 3 months, employing different H2S inlet loading rates (ILR) and an empty bed residence time of 187 s. RESULTS: Biotic performance of the HFMBs demonstrated that the removal efficiency (RE) varied between the different inocula and was in the range of 80-100% for the applied H2S ILR of similar to 5.0-7.5 g m(-3) h(-1). The RE reached a constant value of similar to 100% in both biotic reactors at an ILR of similar to 17.0 g m(-3) h(-1) when using acclimatized inoculum. The biotic HFMBs demonstrated similar to 5-9 times higher H2S flux and similar to 20-26 times higher mass transfer compared to the abiotic control. Surface morphology revealed attached microbial growth on the outer surface of the membranes, while the high throughput sequencing confirmed the richness of H2S oxidizing microbial communities on the shell side. CONCLUSION: The obtained results confirm that the HFMB configuration is suitable for biological treatment of H2S laden waste gas. (C) 2021 Society of Chemical Industry (SCI).