摘要
污水处理厂的氧化亚氮(N_(2)O)排放是重要的温室气体来源,其影响是二氧化碳的265倍。周期循环活性污泥工艺(CAST)因其高效脱氮除磷、低成本和简单流程,在污水处理中广泛应用。通过CAST工艺污水处理厂的全流程N_(2)O排放量检测和排放因子核算,阐明了CAST工艺条件下的N_(2)O的释放特征,结合宏基因组全基因测序技术,进一步阐释了CAST工艺微生物的种群结构特征和氮代谢路径。研究表明:CAST工艺实测计算的N_(2)O排放因子为0.001337 kg N_(2)O-N/kg Ninf,显著低于IPCC提出的序批式工艺N_(2)O排放因子;CAST工艺中丰度最高的脱氮菌属为Competibacter,丰度达到1.92%~2.33%,该菌属在本工艺脱氮过程中起关键作用;CAST工艺的NH_(2)OH氧化过程和NO还原过程涉及温室气体N_(2)O的生成,其中N_(2)O还原酶(nosZ)的KO路径丰度(0.152~0.178)显著高于NO还原酶B亚基(norB,0.095~0.103),有利于CAST工艺将生成的N_(2)O迅速还原为N_(2),进而减少N_(2)O排放量。
Nitrous oxide(N_(2)O)emissions from wastewater treatment plants(WWTPs)are a significant source of greenhouse gases,with a global warming potential 265 times greater than carbon dioxide.Cyclic activated sludge technology(CAST)is widely applied in wastewater treatment due to its high efficiency in nitrogen and phosphorus removal,low cost,and simple operation.This study investigated the N_(2)O emission characteristics under CAST conditions through full-scale N_(2)O emission measurements and emission factor calculations at a CAST-based WWTP.Combined with metagenomic sequencing,we further elucidated the microbial community structure and nitrogen metabolic pathways within the CAST process.The results showed that the measured N_(2)O emission factor for the CAST process was 0.001337 kg N_(2)O-N/kg Ninf,significantly lower than the default emission factor for sequencing batch reactors suggested by the IPCC.Competibacter was identified as the most abundant denitrifying genus in the CAST process,with an abundance of 1.92%-2.33%,playing a crucial role in nitrogen removal.The NH_(2)OH oxidation process in the complete nitrification pathway and the NO reduction process in the denitrification pathway were involved in N_(2)O production.Notably,the abundance of the N_(2)O reductase(nosZ)KO pathway(0.152~0.178)was significantly higher than that of the nitric oxide reductase subunit B(norB,0.095~0.103),facilitating the rapid reduction of generated N_(2)O to N_(2) in the CAST process,thereby minimizing N_(2)O emissions.
作者
徐位远
董浩韬
杜至力
李浩
刘颖诗
于翔
罗凡
钱蔚
XU Weiyuan;DONG Haotao;DU Zhili;LI Hao;LIU Yingshi;YU Xiang;LUO Fan;QIAN Wei(Guangzhou Urban Drainage Monitoring Station,Guangzhou 510510,China;Guangzhou Municipal Engineering Design&Research Institute Co.,Ltd.,Guangzhou 510663,China)
出处
《给水排水》
CSCD
北大核心
2024年第S2期386-394,共9页
Water & Wastewater Engineering
基金
广州市水务局水务科技项目(2023-007Fs)
