进水pH值对CASS工艺处理低浓度生活污水中氧化亚氮排放的影响

摘要

Effect of influent pH value on N2O emission from CASS process for low-concentrated domestic wastewater treatment and its mechanism were studied with real-time qPCR and high-throughput 16S rRNA sequencing.The results showed that NH4+ removal rate increased from 39.5％ to 99.7％ when influent pH value was improved from 6.6 to 9.0,with the improvement of TN removal rate (from 37.5％ to 45.7％).Meanwhile,N2O emission increased from 0.32 mg N/L to 0.52 mg N/L in a single cycle.Besides,the abundances of denitrifying funcational genes (nosZ、nirS and nirK) were relatively higher under high influent pH value (8.4 and 9.0).Microbial structure analysis indicated that ammonium-oxidizing bacteria (AAOB) didn't change significantly,while nitrite-oxidizing bacteria (NOB) varied from 2.58％ to 3.42％ in reactors.Dominant denitrifying bacteria in reactors was Dechloromonas (1.36％～ 4.25％) and Zoogloea (0.75％～ 1.26％),dramatic abundance variation of Dechloromonas could be observed under different influent pH value.%考察进水pH对CASS工艺处理低浓度生活污水中N2O排放的影响,利用实时荧光定量PCR和16S rRNA高通量测序分析其机理.结果表明:随着进水pH值由6.6提高到9.0,氨氮去除率由39.5％提高到99.7％,总氮去除率由37.5％提高到45.7％;同时,单周期N2O排放量从0.32 mg N/L增加到0.52 mg N/L.高进水pH值(8.4和9.0)下,反硝化功能基因nosZ、nirS和nirK丰度较高.微生物群落分析表明,随着进水pH的增加,氨氧化菌含量变化不大,而亚硝酸盐氧化菌含量则从2.58％增加至3.42％.反硝化优势菌种为Dechloromonas(1.36％～ 4.25％)和Zoogloea(0.75％ ～ 1.26％),Dechloromonas丰度随进水pH变化较大.