Control of toxic sulfide in mariculture environment by iron-coated ceramsite and immobilized sulfur oxidizing bacteria.

Hydrogen sulfide (H2S) is considered one of the serious toxic pollutants in mariculture environment. Consequently, it is necessary to develop an effective strategy to prevent the production of sulfide. In this study, we modified the ceramsite with iron (ICC) and prepared a microbial agent, i.e., the immobilized sulfur-oxidizing-bacterium on the ICC (SICC), the microbial agent was following dosed in the simulated mariculture systems to control the sulfide pollutant. Results showed that the sulfide removal capacity of the new material ICC reached to 3.42 mg S g-1 in 24 h. Comparably, the microbial agent SICC presented a stable capability in oxidizing sulfide and the sulfide removal was above 65% in test media feeding with 600 mg L-1 sulfide even after five times of recycling. The microcosm experiments conducted in the simulated mariculture systems showed that the application of the ICC together with the SICC was able to quickly remove the existing sulfide and persistently inhibit the production of sulfide, the immobilized sulfur-oxidizing-bacterium survived stably in the new environment accounting for 1.22% of total microbial community. Therefore, dosing the ICC and SICC simultaneously might be a preferable strategy and presented a promising perspective in remediating the deteriorated mariculture environment.