【作者】 王刚；

【导师】 杨凤林；

【作者基本信息】 大连理工大学 ， 环境工程， 2017， 博士

【摘要】 近年来,以厌氧氨氧化过程为核心的生物脱氮技术已成为低C/N废水处理领域的研究热点。由于厌氧氨氧化细菌倍增时间长(11天),并且对有机物、溶解氧和亚硝氮等环境因素非常敏感,导致了厌氧氨氧化技术存在反应器启动周期长、工业化应用局限性大等问题。针对上述问题,本文以污泥消化液为处理对象,设计以同时亚硝化、厌氧氨氧化和反硝化(SNAD)为核心技术的低能耗旁侧污水处理工艺,启动国内第一个基于SNAD技术的脱氮实际工程,旨在解决厌氧氨氧化技术工业化应用的瓶颈,重点研究厌氧氨氧化过程的快速启动及SNAD 一体式生物脱氮工艺的可行性,并且对SNAD系统的最佳运行条件、微生物菌群变化以及实际工程的启动策略进行详细的研究。取得的创新研究成果包括以下几点:(1)通过实验得出,储存在4℃下的厌氧氨氧化污泥活性恢复速度要比常温储存的污泥快,并且恢复过程中的污泥沉降性、粒径等性状也优于常温储存的污泥。添加了 0.1 g/L氧化石墨烯的污泥活性恢复速度要比未添加的快,并且污泥的颗粒化程度高,沉降性好。(2)通过响应曲面优化法获得了间歇曝气SNAD-MBR工艺的最佳运行条件:进水C/N=0.42-0.55、曝气周期(开/关)=1min/(2.5-3.1)min 和空气流量=0.48-0.51 L/min。在最佳运行条件下,总氮和COD的去除率分别达到92.4%和98.1%,建立了一种适合亚硝化细菌、厌氧氨氧化细菌和反硝化细菌耦合脱氮的反应器型式和运行控制模式。在最佳运行条件下,SNAD系统中厌氧氨氧化过程去除了进水总氮的76.1%,反硝化过程去除了进水总氮的19.0%和进水COD的95.0%。在形成的SNAD颗粒中,菌群的空间分布受DO浓度影响。FISH(fluorescence in suit hybridization)结果显示亚硝化细菌多分布在颗粒外部以便于利用氧气,而厌氧氨氧化细菌和反硝化细菌大都分布在内部厌氧环境。实验中采用自产气+空气混合曝气的方式实现了对系统低DO浓度的控制,同时高强度的曝气减轻了膜污染,使厌氧膜生物反应器能够长周期稳定运行。(3)成功启动了中试亚硝化-厌氧氨氧化反应器,进水为污泥消化液,通过控制DO浓度 0.3-0.8 mg/L、FA(free ammonia)浓度 0.7-8.4 mg/L 以及 FNA(free nitrous acid)浓度0.02-1.0 mg/L可以实现高效的亚硝化过程,为厌氧氨氧化过程提供稳定的进水。在厌氧氨氧化反应器的启动过程中,投加3.5 mg/L的盐酸羟氨可以加快菌种的活性恢复速度。厌氧氨氧化反应器稳定运行至148天,NRR(nitrogen removal rate)达到1.24 kg N/(m3’d),污泥的 SAA(specificANAMMOX activity)达到 1.01 kg N/(m3`d),厌氧氨氧化反应器的比输入功率为0.065-0.097 kW/m3,菌种呈现出良好的颗粒性。从第0天至第120天,厌氧氨氧化污泥中细胞色素c的含量由0.42±0.10增长至5.77±1.00 μmol/g VSS,颗粒污泥中的细胞色素c含量要高于絮状污泥。高通量测序结果显示,中试反应器中厌氧氨氧化污泥的主要种类为Candidatus Brocdia。在进水氮负荷率(NLR)稳定的前提下,采用大流量低浓度(低HRT,低进水氮浓度)的进水方式可以加快反应器中厌氧氨氧化细菌的增殖速度。(4)基于SNAD-MBBR工艺处理污泥消化液的实际工程启动分为两步:第一步,启动亚硝化-厌氧氨氧化串联式脱氮工艺培养厌氧氨氧化污泥;第二步,待培养得到较多的种泥后启动SNAD 一体式脱氮工艺。厌氧氨氧化过程的启动中,将填料在中试厌氧氨氧化反应器内进行预挂膜后再接种至实际工程反应池中有助于厌氧氨氧化阶段的快速启动及菌种富集,以硝化污泥和厌氧氨氧化污泥作为种泥可以成功地启动厌氧氨氧化过程,并且脱氮性能良好。根据厌氧氨氧化池中的污泥量,逐渐混合SNAD池1的亚硝化污泥与SNAD池2的厌氧氨氧化污泥,启动SNAD 一体式脱氮工艺。经过2个月的调试,SNAD池1和池2的总氮去除率分别达到68%和71%,COD去除率分别达到55%和60%。高通量测序结果显示SNAD池中同时检测到了亚硝化细菌、厌氧氨氧化细菌和反硝化细菌的存在,表明SNAD工艺启动成功。另外,测得反应器池中的厌氧氨氧化细菌主要以Candidatus Brocadia为主。更多还原

【Abstract】 Recently,the biological denitrification technology based on anammox process has been the research focus in the low C/N wastewater treatment.However,anammox activity is susceptible to environmental conditions,such as organic carbon,DO,and NO2--N.The long double time of anammox bacteria(11d)results in long start-up period problem of anammox process.The above problems limit the full-scale application of anammox process.In this study,a low-energy side stream biological treatment process based on simultaneous partial nitrification,anammox and denitrification(SNAD)process was designed to treat sludge digester liquor,which was also aimed to break the bottleneck of anammox industrial application.The first full-scale SNAD reactor for sludge digester liquor treatment was established in China.The fast start-up of anammox process and the feasibility of SNAD prcess were mainly investigated.The optimal operating parameters and change of the microbial community in the SNAD process were studied.The start-up and operation strategy of the full-scale application of SNAD process were detailed introducted.The main innovative research results of this study have been obtained as follows:(1)The activity of anammox bacteria stored at 4 ℃ reactivated faster than the anammox bacteria stored at the room temperature through the contrast experiment,and the sludge characters during the reactivating process,including settleability and particle size,were also better.Adding 0.1 g/L graphene oxide(GO)promoted the reactivation rate of the anammox bacteria and contributed to forming anammox granules which showed good settleability.(2)The operating parameters of the intermittent aeration SNAD-MBR(influent carbon to nitrogen ratio(C/N),alternating aerobic/anaerobic(Tae/Tan)period and air flow)were optimized through response surface methodology(RSM).The optimal operating parameters were:a C/N of 0.42-0.55,a Tae/Tan of 1 min/(2.5-3.1)min and an air flow of 0.48-0.51 L/min.Under these conditions,the TN and COD removal efficiencies was 92.4%and 98.1%,respectively,and indicating that a reasonable control operation model and nitrogen removal process by the cooperation of partial nitrification,anammox and denitrification were established.In the SNAD process,the total nitrogen(TN)removal by anammox process was 76.1%,and the denitrification process contributed to 19.0%of TN removal and 95.0%of COD removal.The spatial distribution of microbial community in the SNAD granules depended on the DO concentration.FISH(fluorescence in suit hybridization)analysis showed that the biomass in the outer part of the SNAD granule was mostly AOB,while ANAMMOX and denitrifiers were in the inner anoxic part.In this study,the recycling gas(air and biogas)sparging for controlling low DO concentration and relieving membrane fouling was successfully operated to realize the long-term operation of the anerobic membrane.(3)A pilot-scale partial nitrification-anammox(PN/A)reactor was successfully started up for sludge digester liquor treatment.An efficient PN process was obtained by controlling the concentration of DO(0.3-0.8 mg/L),free ammonia(0.7-8.4 mg/L)and free nitrous acid(0.02-1.0 mg/L).A stable anammox-suited effluent was obtained through the PN process.During the start-up of anammox process,adding 3.5 mg/L hydroxylamine enhanced the anammox reactivation rate.On day 148,the nitrogen removal rate(NRR)of anammox reactor was 1.24 kg N/(m3 d)and the specific anammox activity(SAA)was 1.01 kg N/(kg VSS.d).The bacteria exhibited improved granule properties at a specific input power between 0.065 and 0.097 kW/m3.The heme c content in the anammox sludge increased from 0.42 ±0.10 to 5.77± 1.00 μmol/g VSS from day 0 to 120.And the heme c content in the anammox granule sludge is higher than that in the flocculent sludge.High-throughput sequencing techniques demonstrated that Candidatus Brocadia was the dominant genus in the anammox reactor.Keeping a constant influent nitrogen load rate(NLR),low hydraulic retention time(HRT)can promote the growth rate of the anammox bacteria.(4)The start-up of full-scale sludge digester liquor treatment process based on SNAD-MBBR was divided into two stages.Firstly,the tandem-type PN/A process were started up for the proliferation of anammox bacteria;secondly,the integrated SNAD process was started up.After biofilm developing on the carriers,the carriers were transfered from the pilot-scale anammox reactor to the full-scale reactor,which was favorable for the fast start-up of full-scale anammox reactor and enrichment of anammox bacteria.The anmmox process with a good nitrogen removal performance was successfully started up by mixing the nitrification sludge and anammox sludge as inoculum.According to the biomass concentration in the anammox reactor,the nitrosation sludge and anammox sludge were gradually mixed to start up the SNAD process.After 2 months,the nitrogen removal efficiency of the SNAD reactor 1 and 2 reached 68%and 71%,respectively,and the COD removal efficiency reached 55%and 60%,respectively.High-throughput sequencing techniques demonstrated the coexistence of ammonia oxidizing bacteria,anammox bacteria and denitrifying bacteria in the SNAD reactor,indicating the successful start-up of the SNAD process.In addition,Candidatus Brocadia was the dominant anammox genus in the SNAD reactor.更多还原