[Effects of Aeration Strategy on Denitrifying Performance of Activated Sludge Processes in Treating Low-Carbon-Source...

In this study, the effects of aeration strategy on nitrogen removal performance of activated sludge processes in treating low-carbon-source municipal wastewater were investigated. Two aeration strategies (continuous aeration (CA) and intermittent aeration (IA)) were evaluated, and the long-term performance of activated sludge processes employing these strategies in treating wastewater with C/N=3 were analyzed. The results demonstrated that the total nitrogen removal efficiency in CA was 17.92% higher than that in the IA process. Meanwhile, the carbon source utilized in nitrogen removal in CA was 44.29% higher compared with the IA process. Furthermore, the results of 16S rRNA sequencing showed that relative abundances of denitrifying bacteria in CA and IA were 5.86% and 2.06%, respectively, suggesting that the CA process has better denitrification ability when treating low-carbon-source wastewater. In addition, 16S rRNA sequencing gene prediction was utilized to analyze the in-depth mechanisms. The results demonstrated that genes involved in membrane transport, carbohydrate metabolism, and cell composition were more highly expressed in CA. The enhancement of metabolic activity under continuous aeration strengthened microbial carbon source utilization. Therefore, the activated sludge process under continuous aeration was more efficient in treating low-carbon-source municipal wastewater. This study provides ideas for low-carbon-source municipal wastewater treatment.