包埋反硝化填料强化二级出水深度脱氮性能研究及中试应用

Research on Denitrification Performance of Enhanced Secondary Effluent by Embedded Denitrification Filler and Pilot Application

利用包埋广谱性高效反硝化填料处理城市污水厂二级出水,可有效降低出水总氮(TN)浓度,本研究共分为两部分,D1阶段研究了包埋反硝化填料对污水厂二级出水的适应性、TN去除效果、稳定运行及填料反冲洗的工况条件;D2阶段研究了填料在中试条件下稳定运行1 a脱氮性能的变化,并通过高通量测序和荧光定量分析(q PCR)手段,研究对比了包埋填料运行前后微生物种群的变化规律.通过研究发现,包埋反硝化填料在水温为(24±1)℃、pH为7.1、HRT为1 h和填充率为10%,投加乙酸钠保证碳源充足的条件下稳定运行7 d,即可适应二级出水水质,实现出水总氮<5 mg·L^-1.通过对比研究不同水力停留时间(HRT)对填料TN去除效果的影响,得出适宜的HRT为30 min,填充率为10%的运行条件,在7.2 m3·d^-1的进水条件下经过1 a的稳定运行,TN去除率最高可达到90.42%,出水总氮可稳定在5 mg·L^-1以下.通过对比反冲洗效果,确定了反冲洗强度为5.2 L·(m2·s)^-1,周期为每3 d进行一次.高通量测序和荧光实时定量PCR分析结果表明,运行前后填料上反硝化功能菌属的丰度及拷贝数都有了明显增长,这说明细菌在包埋条件下可实现良好的自我生长.

The use of an embedded broad-spectrum high-efficiency denitrification filler to treat secondary effluent from municipal wastewater treatment plants can effectively reduce total nitrogen(TN)concentration of the effluent.This study consists of two parts.The D1 stage studies the adaptability of the secondary effluent based on the embedded denitrification,removal effect of total nitrogen,stable working conditions,and backwashing conditions;In the D2 stage,the change in the nitrogen removal performance of the filler under the condition of a year-long stable operation was studied.The variation in the microbial population before and after the operation of the embedded packing was studied by high-throughput sequencing and real-time quantitative PCR detecting system real-time(q PCR).In this research,the embedded denitrification filler had a water temperature of(24±1)℃,pH:7.1,hydraulic retention time(HRT):1 h,and filling rate:10%.Sodium acetate was added to ensure stable operation for seven days.Under adequate carbon source conditions,the filler can adapt to the quality of secondary effluent water and achieve effluent TN<5 mg·L^-1.By comparing and studying the effect of different HRT on the removal of filler TN,it is concluded that HRT is 30 min and the filling rate is 10%.After a year of stable operation under 7.2 m3·d^-1 influent conditions,the TN removal rate can reach 90.42%,and the total nitrogen in the effluent can be stabilized below 5 mg·L^-1.In comparison with the backwashing effect,the backwashing strength was 5.2 L·(m2·s)^-1,and the cycle is three days long.High-throughput sequencing and real-time quantitative PCR analysis results show that the abundance and copy number of denitrifying functional genus in the filler before and after the operation exhibited significant changes,which indicated that the bacteria could achieve good self-growth under embedding conditions.