| There is an urgent need for the treatment of organic wastewater containing sulfur and nitrogen in China.Biological denitrifying sulfide removal process can effectively remove pollutants containing sulfur and nitrogen in wastewater and recover elemental sulfur from wastewater.Due to the multiple types of functional microorganisms and complex metabolism in the denitrification and desulfurization reactor,the formation rate of elemental sulfur is low and unstable.Bioaugmentation can be used to solve these problems in an efficient and low-cost way.So this reseach investigate the effects of different nutrient conditions on the denitrifying sulfide removal process,based on sulfur recovery of wastewater denitrifying sulfide removal.The succession of microbial community was explored and the core functional microorganisms were identified depending on high-throughput sequencing platform.The role and interaction relationship of functional microorganisms in the biological denitrifying sulfide removal process were understood through specific screening strategies of functional bacteria and functional identification of strains,which laid a theoretical foundation for the engineering application of bioaugmentation.By changing the nutrient conditions of the reactor operation(switching from autotrophic condition to heterotrophic condition and then to mixotrophic condition)and setting different inorganic carbon concentration and influent pollutant concentration in mixotrophic conditions,it was determined that mixotrophic conditions were more conducive to the removal of pollutants and the conversion of elemental sulfur in the system,and the optimal concentration of organic and inorganic carbon was 368 mg/L and 15.9 mg/L.Under this condition,the system can completely remove sulfide and nitrate,and the sulfur recovery of wastewater denitrifying sulfide removal reached 60%,better than others.Microbial analysis based on 16 S r RNA High-throughput sequencing showed that there were 7 advantage bacterium in the denitrification and desulfurization system,and the advantage bacterium of different nutritional conditions were diffierent,and Thauera,Arcobacter and Azoarcus are the core dominant bacteria under mixed environment.By analyzing the succession of microbial community at different stages,it was found that the increase of elemental sulfur generation rate was always accompanied by the increase of Arcobacter abundance,which reached 50% under the optimal carbon source condition.The seven strains were isolated and identified,and the desulfurization and denitrification performance of the seven strains was studied.It was found that all the seven strains had the desulfurization and denitrification function.Besides,Thauera SP.MZ1 T,Arcobacter Cloacae STR.Sw28-13 and Azoarcus SP.NSC3 had better desulfurization and denitrification performance than other strains.But through the network diagram of microbial interaction,it was found that the correlation between the three core bacteria was weak and there was a competitive relationship.Based on microbial community analysis,Arcobacter cloacae str.SW28-13 is considered as core microorganism in biological denitrifying sulfide removal,which possessed the high capacity to recover sulfur.Arcobacter Cloacae STR.Sw28-13 was made into biofortifier in preparation for future engineering applications. |
