基于甲烷氧化菌的城镇污水厂尾水极限脱氮系统构建及机制

Construction and Mechanism of Methanotroph-based Ultimate Denitrification System for Tailwater of Urban Sewage Plants

好氧甲烷耦合反硝化(AME-D)在城镇污水厂尾水深度脱氮方面具有巨大的应用潜力,研究采用改良型反硝化生物滤池,利用低浓度甲烷构建出AME-D极限脱氮系统.研究发现该系统在间歇式运行方式下,出水中总氮和氨氮的平均浓度能达到1.05 mg·L^-1和0.54 mg·L^-1,其平均去除率分别为94.77%和93.30%.拉曼光谱分析结果显示,由NO-3对称伸缩引起的峰明显消失,由醇COH面外弯曲或C-H面外弯曲振动吸收引起峰明显增强,甲烷被氧化形成的中间产物可能主要为醇类物质.16S rRNA基因测序结果表明,系统中的甲烷氧化菌主要为Methylocystis(0.27%)、Methylosarcina(0.10%)和Methyloparacoccus(0.12%),反硝化菌主要为Pseudomonas(56.92%)、Paenibacillus(3.52%)和Lysinibacillus(3.00%),硝化菌主要为Nitrospira(0.1%),说明AME-D极限脱氮系统的脱氮功能是由好氧甲烷氧化菌、反硝化菌和硝化菌协同实现.

With great practical potential of aerobic methane coupled to denitrification(AME-D)in deep denitrification of tailwater in urban sewage plants,an AME-D extreme denitrification system with low concentration of methane,was established in an improved denitrification biofilter.The finding indicated that in an intermittent operation mode,the average concentration of total nitrogen and ammonia nitrogen in the effluent could reach 1.05 mg·L^-1 and 0.54 mg·L^-1,and the average removal rate was 94.77%and 93.30%,respectively.According to Raman spectral analysis,the crests formed by NO■symmetric stretching disappeared,and crests formed by the vibration and absorption,where the outer alcohol COH plane or the C-H plane was bent,were significantly enhanced,so the intermediate products produced during which methane was oxidized may be alcohols.16 S rRNA gene sequencing results showed that dominant methanotrophs included Methylocystis(0.27%),Methylosarcina(0.10%),and Methyloparacoccus(0.12%),dominant denitrifying bacteria were Pseudomonas(56.92%),Paenibacillus(3.52%),and Lysinibacillus(3.00%),and the dominant nitrifying bacteria were Nitrospira(0.1%)in this system.Thus,it could be concluded that synergism of aerobic methanotrophs,denitrifying bacteria,and nitrifying bacteria could lead to extreme denitrification.