Performance and characteristic of a haloalkaliphilic bio-desulfurizing system using Thioalkalivibrio verustus D301 for efficient removal of H2S

[Display omitted] •An efficient haloalkaliphilic bio-desulfurizing system for removal of H2S.•The selectivity of sulfur products is related to the level of oxidization-reduction potential (ORP).•The linear relationships between sulfide load and ORP as well as aeration rate were showed.•The gradient distributions of ORP and sulfurous compounds in bioreactor were revealed.•The morphology difference in the bioreactor and shake flask and settlability of sulfur particles were presented. Haloalkaliphilic biological desulfurization is attracting people's attention due to its remarkable economy and good performance. In this study, a bio-desulfurizing system was developed based on a sulfur-oxidizing bacterium Thioalkalivibrio versutus D301 to treat H2S under haloalkaliphilic conditions. Results showed the optimum performance of the system was obtained under sulfide load of 3.27 g/L/d and oxidization-reduction potential (ORP) value of −395 mV. The selection of elemental sulfur and sulfate reached 86.19 % ± 3.02 % and 8.6 ± 0.28 % under these conditions. Then, the obvious linear relationships between sulfide load and ORP as well as aeration rate were revealed. The gradient variations of ORP and sulfurous compounds concentration with bioreactor depth were revealed, which proved the existence of spatial and temporal heterogeneity in the bioreactor. The morphology difference of sulfur particles from bioreactor and shake flask implied the key role of operating conditions in shaping particle morphology, and it was found that 56.3 % of total S° particles were harvested within 2 h by gravity settling. This study will provide a valuable reference for the design of bio-desulfurizing equipment and the optimization of operational conditions in the industrial process in the future.