【作者】 吴鹏；

【导师】 沈耀良；

【作者基本信息】 江南大学 ， 环境工程， 2013， 博士

【摘要】 水体富营养化是太湖流域亟待解决的重大环境问题之一，控制营养元素进入水体是降低水体富营养化风险的有效手段。而城市污水富含大量氮，磷等引起水体富营养化的污染物，故开发一种新型的更加有效的城市污水处理工艺是十分有必要的。为此，结合厌氧折流板反应器（anaerobic baffled reactor, ABR）和膜生物反应器（membrane bioreactor,MBR）各自优势，构建优化组合工艺（CAMBR），以克服传统活性污泥法系统的不足，解决传统MBR工艺存在的问题，减缓膜污染进程，增强其降解有机污染物的能力，同时强化脱氮除磷效果，对进一步提高处理污水出水水质及其实际生产应用具有重要的理论和现实意义。主要研究结果如下：（1）CAMBR工艺历经72天启动成功，ABR各隔室内混合液悬浮固体（MLSS）维持在28g·L^-1左右，好氧池和膜池维持在6g·L^-1左右，污泥浓度，污泥活性和出水水质稳定。启动阶段ABR内出现了最大粒径3mm的厌氧颗粒污泥及MBR内最大2mm的好氧颗粒污泥，标志着反应器成功启动。CAMBR工艺启动后期稳定运行状况下，系统出水化学需氧量（COD）、氨氮（NH₄⁺-N）、总氮（TN）和总磷（TP）的平均浓度分别在32、2.3、13.3和1.22mg·L^-1左右，平均去除率分别达91%、92%、72%和70%。（2）为保证CAMBR工艺良好的出水水质，综合考虑系统运行效果，可以确定工艺的最佳运行条件是水力停留时间（HRT）为7.5h，R为200%以及溶解氧（DO）为3mg·L^-1。在此运行条件下，系统出水COD平均浓度为25.6mg·L^-1，出水NH₄⁺-N平均浓度为0.5mg·L^-1，出水TN平均浓度为10.5mg·L^-1，出水TP平均浓度为0.4mg·L^-1，完全能够满足《城镇污水处理厂污染物排放标准》（GB18918-2002）一级A标准，也符合我国回用水水质标准的要求。（3）整个工艺实现了厌氧反硝化，厌氧释磷，缺氧反硝化除磷，好氧硝化和吸磷等微生物相的有效分离。在HRT为7.5h，R为200%，DO为3mg·L^-1，好氧区MLSS浓度为8000mg·L^-1的条件下，系统对NH₄⁺-N和TN的去除率分别可达99%和80%，其出水NH₄⁺-N和TN浓度平均分别为0.33mg·L^-1和10.6mg·L^-1。好氧池和膜池存在同步硝化反硝化作用，强化了系统脱氮效果。出水TP浓度平均为0.31mg·L^-1，去除率为93%。其中MBR对NH₄⁺-N、TN和TP的强化去除率分别为14%、11%和18%。工艺生物量大，处理功能强，实现了稳定、高效的同步脱氮除磷功效，出水水质优良，满足小规模城镇污水处理的新型、高效、集成式一体化要求。（4）在最佳运行条件下(HRT为7.5h，R为200%，DO为3mg·L^-1)，工艺对进水水质的转换具有较强的适应能力，可对试验的两种实际污水进行有效的处理，出水水质稳定而优良，出水COD浓度低于28mg·L^-1，NH₄⁺-N浓度低于0.6mg·L^-1，TN浓度低于12.6mg·L^-1，TP浓度低于0.42mg·L^-1，完全能够满足《城镇污水处理厂污染物排放标准》（GB18918-2002）一级A标准。不同温度环境下，系统对COD的去除效果很好，TN与NH₄⁺-N的去除效果正相关性良好，当工艺稳定运行之后，总体上出水水质较好。中温环境，工艺出水水质良好。高温环境，TN去除率稳定在70%左右，出水浓度为9mg·L^-1左右；TP去除率为73%左右，出水浓度为0.8mg·L^-1左右。而低温环境，TN去除率仅为57%，出水浓度为15mg·L^-1左右；TP去除率稳定在67%左右，出水浓度为1mg·L^-1左右。故为取得较好的脱氮除磷效果，系统应该采取保温措施。另外，间歇抽吸出水、水力反冲是减缓膜污染和延长膜组件使用寿命的重要措施，但长期运行则需化学药洗以彻底清除微生物代谢产物等不可逆污染物。膜污染与污泥浓度、膜通量、曝气量三种因素密切相关。（5）采用聚合酶链式反应-变性梯度凝胶电泳（polymerase chain reaction withdenaturing gradient gel electrophoresis, PCR-DGGE）和荧光原位杂交（fluorescence in situhybridization, FISH）技术，对CAMBR工艺整个运行过程中系统内的微生物菌群结构动态变化和各区内优势种群进行分析，结果表明：整个试验过程，系统内菌群呈多样性分布，同时优势菌群突出。在同一时期内，各个反应池菌群相似性较高，微生物菌群结构在相对较短的时间内改变不明显，各个隔室通过各自不同的微环境改变微生物的生理状态，使得微生物在不同反应池中能够发挥不同的作用。反应器内硝化菌群和聚磷菌随试验的运行而逐渐增加，有效保证了系统的脱氮除磷效果。在系统最佳运行条件下(HRT为7.5h，R为200%，DO为3mg·L^-1)，系统内三种菌得到了富集，并且占全菌的比例较高，是CAMBR工艺高效脱氮除磷的直接原因。更多还原

【Abstract】 Eutrophication is one of serious environmental problems in LakeTaihu. It is known thatcontrolling nutrient input is the most effective way of reducing the risk of blooms. However,domestic sewage contains abundant phosphorus and nitrogen pollutants that causeeutrophication of water bodies, and it is therefore necessary to identify the optimumbioreactor to treat municipal wastewater effectively. In order to explore a new and efficientwastewater treatment process, the combined ABR-MBR process （CAMBR） with thecharacteristics and advantages of both reactors was optimized and the shortcomings of bothreactors were overcome. It delayed the process of membrane fouling and improved theefficiency of nutrient removal. The studies have theoretical and practical significance onimproving the quality of effluent and its application. The main research results of thisdissertation were shown as follows:（1） During the72days start-up of the system, granular sludge was observed in the ABRand MBR with the diameters of3mm and2mm respectively at the end of start-up. Theaverage MLSS in ABR and MBR were28g·L^-1and6g·L^-1, respectively. The system couldacquire stable removal efficiencies of COD, NH₄⁺-N, TN and TP about91%,92%,72%and70%respectively, correspondingly with an average effluent of32,2.3,13.3and1.22mg·L^-1.（2） In order to ensure the good effluent quality and consider the performance of theprocess, optimal operation conditions with a hydraulic retention time of7.5h at a recycle ratioof200%and dissolved oxygen of3mg·L^-1was shown to achieve higher quality effluent withchemical oxygen demand, ammonium, total nitrogen and total phosphorus of26,0.5,10.5and0.4mg·L^-1, respectively. The effluent quality met the Level-one A criteria specified inDischarge Standard of Pollutants for Municipal Wastewater Treatment Plant （GB18918-2002）.（3） The whole process achieved an effective separation of microorganism’s phases, suchas anaerobic denitrification, anaerobic phosphorus release, anoxic denitrification andphosphorus removal, aerobic nitrification and phosphorus uptake. The average removal ratesof COD, NH₄⁺-N, TN and TP reached93%,99%,79%and92%, respectively,correspondingly with the COD, NH₄⁺-N, TN and TP effluent of24,0.4,10.6and0.31mg·L^-1with a HRT of7.5h at a recycle ratio of200%and DO of3mg·L^-1. The MBR enhancedNH₄⁺-N, TN and TP removal rates of14%,11%and18%, respectively. The process was ableto maintain a stable performance with high quality effluent during the period. The process haslarge biomass and is efficient on pollutants removal. In addition, it satisfies the requirementsof new, efficient and integrated process. Therefore, it is suitable to apply in small-scalemunicipal wastewater treatment plant.（4） The process had a good ability to adapt to the influent shift, and was able to achieve the simultaneous nutrient removal of both two kinds of municipal wastewaters effectivelywith the high quality effluent chemical oxygen demand, ammonium, total nitrogen and totalphosphorus of lower than28,0.6,12.6, and0.4mg L^-1, respectively. The CAMBR had goodremoval efficiencies of COD under different temperature conditions, the removal efficienciesof TN had a positive correlation to NH₄⁺-N, and the effluent quality is good in the stableoperation of the system. Furthermore, the effluent quality of the middle temperature conditionwas the best. In addition, TN removal efficiencies were stabilized around70%with theeffluent concentration about9mg·L^-1, and TP removal efficiency was about73%with theeffluent concentration about0.8mg·L^-1in high temperature environments. While the processoperated in low temperature environment, TN removal efficiency was only57%with theeffluent concentration of5mg·L^-1, and TP removal efficiency of67%with the effluentconcentration about1mg·L^-1. Thus, in order to achieve better nitrogen and phosphorusremoval efficiencies, insulation measures should be taken to keep the process warm.Intermittent pumping water, hydraulic recoil can effectively reduce the degree of membranefouling, but chemical clean is necessary to completely remove irreversible pollutants.Membrane fouling is closely related to three factors of sludge concentration, membrane fluxand aeration rate. Intermittent suction, scouring aeration, regular drug-wash, and on-linehydraulic backwash as a mean of inhibiting membrane fouling, ensure the sustainable runningof the CAMBR system.（5） The polymerase chain reaction with denaturing gradient gel electrophoresis andfluorescence in situ hybridization were used to analyze the structure of microbial communitythroughout the whole experient and the dominant bacterial composition of the activatedsludge in each compartment of the CAMBR. Throughout the process, the microbialpopulation within the system maintained diversity in distribution, while the dominant florawas prominent. During the same period, microbial population in each compartment had highsimilarity, and the structure of microbial community had no significant changes within arelatively short period. The physiological state of the each compartment was changed throughrespective different microenvironments. Thus, microorganisms were able to play a differentrole in the different compartments. The nitrifying bacteria and phosphorus accumulatingorganisms gradually increased with the running of the experiment, guaranteeing the efficiencyof nitrogen and phosphorus removal in the system. The specialized microorganisms, includingnitrifying bacteria （ammonia-oxidizing bacteria and nitrite-oxidizing bacteria）, andphosphorus accumulating organisms, were enriched in this process. The enrichedmicroorganisms in the system were the underlying reason why the CAMBR was efficient fornitrogen and phosphorus removal.更多还原