Performance and Microbial Community of Novel Three-Stage Waterfall Aeration Grooves Biofilm Reactor for Treating Decentralized Wastewater in Rural Areas

摘要

In this study, a novel three-stage filler-based waterfall aeration grooves biofilm reactor (WAGBR) was designed to treat decentralized wastewater. This reactor is suitable for rural areas of China for its low cost and easy maintenance, and it can be used for treating wastewaters of different qualities and volumes. Chemical oxygen demand (COD), nitrogen removal efficiency, and the microbial community structure were evaluated in different stages of the WAGBR for 50 days. Results obtained for each stage were compared with those of other stages. COD and ammonium nitrogen (NH_(3)-N) removal efficiency remained at ∼80% after 20 days and three stages played different roles in removal of specific pollutant. High-throughput sequencing was used to investigate composition of the microbial community in the treatment system. The microbial richness of stage 1 was higher than that of stage 2 and it indicated that the raw wastewater had a higher biodegradability after stage 1. Microbial diversity in the stage 1 and stage 2 was similar to each other, but was much higher than that in stage 3. Major classes present were Alphaproteobacteria (average abundance of 21.7%), Betaproteobacteria (20.8%), Gammaproteobacteria (12.2%), Sphingobacteriia (9.5%), Cytophagia (8.0%), Acidobacteria_Gp4 (6.3%), Acidobacteria_Gp3 (6.0%), Flavobacteriia (2.9%), Deltaproteobacteria (2.6%), ML635J-21 (2.1%), Saprospirae (1.8%), and Bacteroidia (1.2%). These results could provide important guidance for the use of decentralized wastewater treatment systems in rural areas of China.