Application of a Partial Nitrogen Lab-Scale Sequencing Batch Reactor for the Treatment of Organic Wastewater and Its N2O Production Pathways, and the Microbial Mechanism

Sustainability

Zhipei Liu¹  Ying Liu¹  Boyan Ma¹ 

[1] State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China;

关键词: partial nitrification;    organic wastewater;    N₂O emissions;    microbial mechanisms;    heterotrophic nitrifiers;   

DOI  :  10.3390/su14031457

来源: DOAJ

【 摘 要 】

Partial nitrification (PN) is a widely used wastewater treatment process. Here a lab-scale sequencing batch reactor for PN (PN-SBR) was constructed and run with artificial organic wastewater for 225 days. Results showed that the SBR reached a stable PN state after 174 days of operation and >98% of NH₄⁺-N was removed and >60% was converted to NO₂⁻-N with low effluent NO₃⁻-N content. In a PN-SBR cycle at stage IV, the release of N₂O was accompanied by the production of hydroxylamine, occurring mainly in the conversion from anaerobic to aerobic phases, and the amount of N₂O produced was about 6.3% of the total nitrogen. The N₂O isotopic signature results suggested that hydroxylamine oxidation was the main pathway for N₂O production. Illumina MiSeq sequencing results showed that Proteobacteria and Bacteroidetes were the dominant phyla throughout the operation period. Many heterotrophic nitrifiers were significantly enriched, leading to ammonia removal and nitrite accumulation, including Acidovorax, Paracoccus, Propionibacteriaceae_unclassified, Shinella, Comamonas and Brevundimonas. Representative strains were isolated from the reactor and they were capable of efficiently producing nitrite from ammonia. These results provide a guide for the direct running of PN reactors for treating organic wastewater and help to understand the microbial processes and N₂O release pathways and the microbial mechanism of partial nitrification.

【 授权许可】

Unknown