连续流SNAD工艺处理猪场沼液启动过程中微生物种群演变及脱氮性能

Bacterial Community Shifts and Nitrogen Removal Characteristics for a SNAD Process Treating Anaerobic Digester Liquor of Swine Wastewater (ADLSW) in a Continuous-Flow Biofilm Reactor (CFBR)

为了实现合建式连续流同步部分亚硝化、厌氧氨氧化和反硝化SNAD(simultaneous partial nitrification,ANAMMOX,and denitrification)工艺处理实际猪场沼液,保持温度为(30±1)℃,控制溶解氧(DO)为(0.4±0.1)mg·L^-1,首先通过逐步提高模拟进水氨氮浓度来实现SNAD工艺的启动,然后实现SNAD工艺处理实际猪场沼液的稳定运行.同时,采用高通量测序和实时定量PCR(qPCR)技术对反应器启动前后及沼液替换成功时关键生物种群进行分析.结果表明,150 d左右可实现SNAD工艺的启动, 298 d完成实际沼液的替换,其出水(NO-3-N+NO-2-N)/ΔNH+4-N小于0.11,对NH+4-N和TN的平均去除率为63.26%和55.71%.高通量测序结果表明,绿弯菌门(Chloroflexi,相对丰度50.78%)、变形菌门(Proteobacteria, 13.34%)、浮霉菌门(Planctomycetes, 9.26%)是沼液替换成功时污泥中的优势菌门;主要优势脱氮菌属Nitrosomonas的相对丰度由启动前1.55%增加到1.98%;两类具有厌氧氨氧化(ANAMMOX)功能菌CandidatusBrocadia和CandidatusKuenenia的相对丰度分别从启动前0.01%和未检出(<0.01%)增加到4.66%和4.18%;Denitratisoma作为主要的反硝化菌,丰度由启动前未检出(<0.01%)增加到2.06%.qPCR结果表明,与接种污泥相比,沼液替换成功后AOB、ANAMMOX菌和反硝化菌的含量均有明显增加.将SNAD工艺用于实际猪场沼液处理,可实现高效稳定脱氮,节约后续处理成本.

To realize a simultaneous partial nitrification, ANAMMOX(anaerobic ammonium oxidation), and denitrification(SNAD) process treating anaerobic digester liquor of swine wastewater(ADLSW) in a continuous-flow biofilm reactor(CFBR), we first gradually increased the influent ammonium(NH+4-N) concentration, and then enhanced the ADLSW ratio in the influent during operation;dissolved oxygen(DO) was controlled at(0.4±0.1) mg·L^-1 by adjusting the air flow rate, and the temperature was kept at(30±1)℃. Meanwhile, high-throughput sequencing and quantitative PCR(polymerase chain reaction) techniques were used to analyze the bacterial community shifts and the amount of dominant nitrogen removal bacteria. The results demonstrated that a successful start-up of the SNAD process was accomplished in 150 d, and replacement of the actual biogas slurry was completed in 298 d. The effluent(NO-3-N+NO-2-N)/ΔNH+4-N value was less than 0.11, and the average removal rates of NH+4-N and TN(total nitrogen) increased to 63.26% and 55.71%, respectively. Moreover, high-throughput sequencing results demonstrated that the dominant microbial populations at phylum level were Chloroflexi(with a relative abundance of 50.78%), Proteobacteria(13.34%), and Planctomycetes(9.26%). The relative abundance of Nitrosomonas increased from 1.55% to 1.98%. In addition, the relative abundance of CandidatusBrocadia and CandidatusKuenenia increased from 0.01% and(<0.01%) to 4.66% and 4.18%, respectively, and the relative abundance of Denitratisoma increased from(<0.01%) to 2.06%. Meanwhile, qPCR analysis showed that the amounts of ammonia-oxidizing bacteria, ANAMMOX, and denitrifying bacteria increased significantly compared with the inoculated sludge. An efficient and stable nitrogen removal rate can be achieved, and the follow-up processing cost can be reduced, by application of the SNAD treatment process for ADLSW.