LAUSR

Treating low C/N domestic sewage is one of the difficult tasks in wastewater treatment. This study investigated the treatment of low C/N domestic sewage under low dissolved oxygen condition via self-built biological contact oxidation reactor with composite packing and polyurethane suspension packing. Meanwhile, MiSeq high-throughput sequencing was performed on the microbial communities on the surface of the packing to analyze the changes in microbial community structure. The results showed that polyurethane suspension packing reactor had better removal efficacy on NH4–N, TN and COD than the combined packing reactor, and only the effluent indexes of polyurethane suspension packing reactor could reach the first-class A emission standard of Discharge standard of pollutants for municipal wastewater treatment plant (GB 18918-2002). The removal of biological phosphorus of the single-contact oxidation process was not ideal and could be combined with anaerobic reactor. The richness and diversity of the bacterial community in polyurethane suspension packing reactor was higher than those of composite packing reactor. Polyurethane suspension packing reactor contained relatively richer nitrification-related flora Nitrospira, which provide better growth and reproduction conditions for the denitrification-related flora Betaproteobacteria and Denitratisoma. The large amount of facultative heterotrophic bacteria in Proteobacteria had a significant effect on the removal of organic pollutants. This study provides a theoretical basis for subsequent in-depth research and practical application.