Characterization of biofilm bacterial communities in rural drainage system ancillary facilities

Abstract

To investigate the differences in the bacterial communities of biofilms in the appurtenant facilities of rural sewage collection systems, a pilot research setup was constructed. A study was conducted using real sewage collected in a rural area, and the bacterial communities of biofilms in different appurtenant facilities were characterized using Illumina HiSeq high-throughput sequencing technology. The results showed that there were significant differences in biofilm bacterial communities among the different annexes. The biofilms from all four ancillary facilities (drop manhole, turning inspection well, mud trap, and direct inspection well) contained some amounts of denitrifying bacteria (relative abundance >6 %), but lacked ammonia- and nitrite-oxidizing bacteria (relative abundance <0.1 %). The relative abundance of sulfate-reducing bacteria was high (6.32 %), with Desulfobulbus being dominant (4.12 %) owing to the prolonged low dissolved oxygen environment in the sedimentation wells, which are at high risk of accumulating H2S relative to other ancillary facilities. All four ancillary facilities had high abundances of potential disease-causing bacteria (e.g., Acinetobacter and Arcobacter) in the biofilm and in the overwater. Therefore, the biosafety of the effluent should be taken into account in the collection process.

Keywords

• Rural drainage
• Ancillary facilities
• Biofilm
• Bacterial community