强化型硫铁矿自养反硝化工艺深度处理城市二沉尾水研究

Study of advanced treatment of municipal secondary effluent by enhanced pyrite-based autotrophic denitrification process

为实现硫铁矿自养反硝化工艺快速启动,提高出水稳定性,将以硫铁矿为填料的硫自养反硝化生物滤池反应器(1号反应器)作为对照组,分别构建了以硫铁矿/石灰石和硫铁矿/硫黄为填料的强化型硫铁矿生物滤池反应器(2号、3号反应器)处理城市污水处理厂二沉尾水,从去除效果、出水水质的角度来评价强化工艺的可行性,并通过微生物群落分析来探究强化工艺的强化机理.结果表明:当反应温度为31~33℃,水力停留时间(HRT)为2.2 h时,3个生物滤池反应器总氮(TN)去除率分别为91.3%(1号反应器)、84.5%(2号反应器)、100%(3号反应器),出水TN浓度均小于5 mg/L;总磷(TP)去除率分别为91.4%(1号反应器)、85.0%(2号反应器)和100%(3号反应器),TP去除效果随TN去除效果的提升而提升;出水pH基本均能维持在6.8~7.6,体系内硫酸根生成量较低,维持在4.99~5.91 mg(每mg NO_(3)^(-)-N).Thiobacillus作为硫铁矿自养反硝化工艺的核心功能菌属在3号反应器内占据优势地位.以硫铁矿/硫黄为填料的生物滤池反应器不仅可以实现快速启动,也能够取得良好的氮磷去除效果,出水水质稳定,为城市二沉尾水强化处理的硫自养反硝化技术的实际应用提供了理论支持.

In order to realize rapid start-up of pyrite-based autotrophic denitrification(PAD)process and improve effluent stability,biofilter reactor(No.1 reactor)depending on sulfur-based autotrophic denitrification(SAD)process filled with pyrite is used as a control,enhanced pyrite-based biofilter reactors(No.2 and No.3 reactors)are respectively established filled with pyrite/limestone and pyrite/sulfur to treat the secondary effluent of municipal wastewater treatment plant.The feasibility of the two enhanced processes is evaluated from the perspective of both removal efficiency and effluent quality,and the microbial community analysis is used to explore the enhancement mechanism of the enhanced processes.The results show that with the reaction temperature of 31-33℃and hydraulic retention time(HRT)of 2.2 h,the total nitrogen(TN)removal efficiencies of the three biofilter reactors are 91.3%(No.1 reactor),84.5%(No.2 reactor)and 100%(No.3 reactor),respectively,the TN concentration of the effluent is less than 5 mg/L;the total phosphorus(TP)removal efficiencies are 91.4%(No.1 reactor),85.0%(No.2 reactor)and 100%(No.3 reactor),respectively,and the TP removal performance is positively correlated with the TN removal performance.The effluent pH of the three biofilter reactors is ranged from 6.8 to 7.6.The sulfate radical production in all biofilter reactors is low and maintains at 4.99-5.91 mg(per mg NO_(3)^(-)-N).The higher relative abundance of Thiobacillus,the core functional bacteria of pyrite-based autotrophic denitrification process,occurs in the No.3 reactor.In conclusion,biofilter reactor filled with pyrite/sulfur can not only achieve fast start-up,but also achieve good nitrogen and phosphorus removal efficiencies,and the effluent quality is stable,which provides a theoretical basis for practical application of SAD technology in advanced treatment of municipal secondary effluent.