Effects of sewage treatment on microbial community structure of surface water in Xiantao wetland

Abstract:

[Background] With the rapid development of economy in middle and small cities and the improvement of people’s living standard, Which the discharge of domestic sewage is also magnify, resulting in a worsening trend of water quality pollution. [Objective] To understand the effect of domestic sewage treatment on changes of microbial community diversity in wetland surface water. [Methods] Physical and chemical tests were conducted on 6 points of surface water in reference points (?2 000), 200, 400, 600, 3 000 and 5 000 m in constructed wetlands (Xiantao), Then the microbial community structure was analyzed by high-throughput sequencing, and the effects of microbial community structure change and domestic sewage pollution were also discussed. [Results] When the sewage treated by wetland method reached 5 000 m, Chemical oxygen demand (COD), NH4+N, Total nitrogen (TN) and Total phosphorus (TP) reached the first grade standard of pollutant discharge standard for urban sewage treatment plant, and there was a very significant positive correlation between the physical and chemical indexes. The dominant phyla in the studied surface water were Proteobacteria, Bacteroidetes, Actinobacteria, Cyanobacteria, Verrucomicrobia, Firmicutes, Acidobacteria and Chloroflexi. Proteobacteria can be used as an indicator microorganism for the discharge of pollutants from domestic sewage. Actinobacteria, cyanobacteria, verrucomicrobia and Chloroflexi can be used as an indicator microorganism for the purification of domestic sewage. [Conclusion] The changes of microbial community diversity in the surface water environment of Xiantao domestic sewage treatment were compared for the first time, which can make people understand the operation mechanism of constructed wetland and the pollution of surface water environment more clearly from the microbiological level.