The microbial characteristics of rural sewer biofilms and their effects on pollutant removal

Rural sewers are key facilities to collect and transport rural sewage whose microbial characteristics need to be revealed to better understand and improve the biochemical process. In this study, metagenomic method was used to analyze the microbial characteristics of rural sewer biofilms and the effect on pollutant removal was further discussed. Results indicated that rural sewer biofilms contained bacteria (e.g. Pseudomonas), fungi (e.g. Spizellomyces), viruses (e.g. Pbunavirus), and archaea (e.g Methanothrix), including pathogens (e.g. Pseudomonas aeruginosa and Aeromonas hydrophila) and antibiotic resistance genes (target for Aminoglycoside and Tetracycline etc.), while the Ammonia monooxygenase genes (i.e. amoA, amoB, and amoC) was basically absent. Rural sewer biofilms contained abundant Desulfobulbus (similar to 2.40 %) whose relative abundance was nearly 40 times higher than Methanothrix (the predominant archaea). Rural sewer biofilms had the ability to decrease chemical oxygen demand in sewage and generate sulfide and methane but the nitrogen and phosphorus removal ability was limited. This study can provide scientific support for better understanding of biochemical reaction process in rural sewer systems.