城市污水双泥龄复合脱氮工艺的脱氮机理分析

Analysis on Denitrification Mechanism of Double-SRT Hybrid Denitrification Process for Municipal Wastewater Treatment

基于部分厌氧氨氧化的双泥龄复合脱氮工艺能实现自养脱氮和异养脱氮的耦合,在城市污水低成本高效脱氮方面表现出良好的应用潜力。为进一步探究该工艺的脱氮机理,对运行2年的中试反应器开展了脱氮途径解析与优化、主要脱氮功能菌活性测定以及微生物群落结构分析。结果表明,间歇曝气可以促进短程硝化和厌氧氨氧化过程的耦合,当曝气量为20 mL/min[DO为(0.18±0.03)mg/L]时,脱氮效率最高;厌氧氨氧化菌(AnAOB)主要分布在生物膜上,活性为44.60 mg(/gVSS·d),检测到的AnAOB为Candidatus Brocadia,相对丰度为0.28%;氨氧化菌(AOB)和亚硝酸盐氧化菌(NOB)主要分布在悬浮污泥中,活性分别为61.53、86.95 mg(/gVSS·d),检测到的AOB和NOB分别为Nitrosomonas和Nitrospira,相对丰度分别为0.10%、2.10%。

The double-SRT(sludge retention time)hybrid denitrification process based on partial anaerobic ammonia oxidation(Anammox)can realize the coupling of autotrophic denitrification and heterotrophic denitrification,which shows good application potential in low-cost and high-efficiency denitrification of municipal wastewater.To further explore the denitrification mechanism of this process,analysis and optimization of the denitrification pathway,determination of the main nitrogen-removing functional bacteria activity and analysis of the microbial community structure were carried out in a pilot-scale reactor that has been operated for 2 years.Intermittent aeration promoted the coupling of short-cut nitrification and Anammox processes,and the nitrogen removal efficiency was the highest when the aeration rate was 20 mL/min[DO of(0.18±0.03)mg/L].Anaerobic ammonia oxidizing bacteria(AnAOB)were distributed in the biofilm with an activity of 44.60 mg/(gVSS·d),and the detected AnAOB was Candidatus Brocadia with relative abundance of 0.28%.Ammonia oxidizing bacteria(AOB)and nitrite oxidizing bacteria(NOB)were mainly distributed in the suspended sludge,and their activities were 61.53 mg/(gVSS·d)and 86.95 mg/(gVSS·d),respectively.The detected genera of AOB and NOB were mainly Nitrosomonas(0.10%)and Nitrospira(2.10%)respectively.