【作者】 陈杰云；

【导师】 张智；

【作者基本信息】 重庆大学 ， 市政工程， 2013， 博士

【摘要】 目前，城市污水处理厂普遍存在因污水中碳源匮乏而导致脱氮除磷效果不稳定等问题，对生态环境的影响日趋严重。在这种情况下，开发优化碳源有效利用和强化脱氮污水处理工艺技术十分必要。研究将分段进水工艺与好氧生物膜法相结合，使该系统具有节省内回流设施、无需外加碳源、提高系统抗冲击负荷能力及增加系统生物量等优点，通过理论分析、中试试验结合小试试验研究等手段，对组合工艺处理效能进行了系统的研究。以期该工艺在高效脱氮污水领域的应用推广和类似工艺的污水厂升级改造提供指导。为确保组合工艺反应器整体处于推流状态，通过示踪剂流态实验对反应器的结构进行了改造，同时通过Fluent软件进行模拟，证实改造后的反应器推流状态明显，为实现后续生化试验提供了合适的反应器流态。通过对HRT、温度、进水流量分配比、污泥回流比及缺好氧区容积比等因素对组合工艺处理效能影响的研究，系统研究组合工艺的特点和优势，优选合理的参数取值范围。发现组合工艺系统相对于单纯活性污泥系统抗击外界冲击能力明显。在低HRT的情况下，采取增加曝气和减少排泥的措施提高系统的脱氮效果，对于TP采取化学方式予以去除；对于温度的变化，为了保证较好的处理效果，主要采取调整污泥浓度和DO浓度来实现。根据试验城市污水水质条件分析，得到分段进水分配方式为逐级递减。污泥回流比对组合工艺脱氮影响不大，从不影响脱氮效能又能减少能耗的角度出发，采用50%~100%的回流较适宜。在采用最佳进水分流比的前提下，尽量扩大缺氧区所占容积可以提高系统TN去除率。组合工艺好氧区出现了明显的同步硝化反硝化现象，通过小试实验可以发现，各级好氧区的同步硝化反硝化脱氮效能存在明显差别，第一级脱氮效果最佳，第二级次之，第三级最差。同时发现投加填料有助于同步硝化反硝化脱氮能力的提升。在综合考虑各水质指标处理效果情况下，中试反应器在采取梯级曝气溶解氧搭配为0.5mg/L、1.0mg/L、1.5mg/L的工况下运行时，反应器的同步硝化反硝化能力得到了最合理的发挥，并从进水方式和生物膜结合的角度分析了组合工艺的脱氮机理。采用显微镜镜检技术观察系统运行阶段活性污泥及生物膜的微生物组成和形态特征，发现组合工艺的生物相较为丰富，活性污泥与生物膜污泥生物相存在一定的差异，并分析了反应器内的微生物特性及微生物固定化机理。组合工艺在试验期间污泥的表观产率基本上在0.12～0.21kgMLSS/kgCOD之间，明显低于常规活性污泥法。采用环境扫描电镜结果显示污泥絮体及生物膜内外均存在供物质交流的孔洞和通道，为组合工艺系统同步硝化反硝化的发生创造了物质和环境条件。组合工艺反应器各级活性污泥及生物膜上微生物的SOUR和DHA均呈下降趋势，生物活性还受温度和碳源的影响，系统的污泥活性与所处环境中的有机质浓度呈正相关关系。通过对系统菌群多样性指数和相似性分析，每一级的活性污泥和生物膜多样性指数相比较，生物膜的多样性指数高于活性污泥，说明生物膜中的微生物种群更为丰富。同时生物膜样品的相似性明显高于活性污泥，这与生物膜中微生物菌群的多样性更高有关。多级A/O+好氧生物膜组合工艺是一种节能、高效和稳定的污水处理工艺，可运用到新建及改造的实际工程中，并通过调节各运行参数以实现系统的最佳工况，提高出水水质。更多还原

【Abstract】 At present, the prevalent problems in urban sewage treatment plants of nitrogenand phosphorus removal unstable caused by lack of carbon source have influenced onthe ecological environment increasingly serious. In this case, it is necessary to developand optimize the effective utilization of the carbon source and integrate nitrogen andphosphorus removal wastewater treatment technology. The advantages of the systemcombining step-feed process with aerobic biofilm are saving internal reflux facilities, noexternal carbon source, improving system resistance to impact load and increasingsystem biomass, etc. By the means of theoretical analysis, pilot tests combined withsmall scale tests, a systematic study on the performance of the combined process iscarried out to hope to provide guidance of promoting the application in the field oflow-carbon source area and upgrading sewage plants of similar processes.In order to ensure the combined-process reactor in the state of the plug-flow aswhole, the structure of the reactor has been transformed through flow patternexperiments, providing a suitable reactor flow pattern for subsequent biochemical tests.Through the research of HRT, temperature, influent flow distribution ratio, sludgerecycle ratio and anoxic zone volume ratio impacting on the combined process efficacy,the study researchs on the features and advantages of the combined processsystematically, optimizes reasonable range of parameter values. It is found that theefficiency against external shock of the combined process system was more obviouscompared with purely activated sludge system. In the case of low HRT, the measures ofincreasing aeration and reducing sludge can improve denitrification effect of the system,and TP can be removed by chemical approach; temperature changes can be mainlyachieved by adjusting the sludge concentration and DO concentration in order to ensurebetter treatment effect. Through analyzing test urban sewage water conditions, it is foundthat the segmented water distribution pattern is progressively decreasing. The sludgereturn ratio made little influence on denitrification of the combined process, and thereturn ratio of50%to100%is more appropriate in view of not affecting thedenitrification performance and reducing energy consumption. Under the premise ofbest water diversion ratio, maximizing the anoxic zone ’s volume can improve system TN removal.Obvious simultaneous nitrification and denitrification phenomenon appeared in theaerobic zone of th combined proces, it can be found that simultaneous nitrification anddenitrification performance of all levels of aerobic zone differs significantly, the firstlevel best, the second stage, followed by the third level worst. Dosing filler enhance theability of simultaneous nitrification and denitrification. In the case of the treatmenteffect of the overall consideration of various water quality indicators, pilot reactortaking the cascade aeration dissolved oxygen with0.5mg/L,1.0mg/L,and1.5mg/Lrunning condition, simultaneous nitrification reactor denitrification capacity has beenfully played, and the study analyzed denitrification mechanism from the angle of thewater way combined with biofilm.Using microscope microscopic examination technology, through observingmicrobial composition and morphological features of activated sludge and biofilm in therunning stage of the system, it is found that the biofacies are abundant of the combinedprocess,and biofacies of biological activated sludge and biofilm sludge are different,then the study analyzed microbial feature in the reactor and microbial immobilizationmechanism. During the test,sludge observed yield of the combined process are basicallybetween0.12and0.21kgMLSS/kgCOD, significantly lower than the activated sludgeprocess. Environmental scanning electron microscope results showed that holes andchannels for the exchange of substances existe in the floc and biofilm, and they createthe material and environmental conditions for simultaneous nitrification anddenitrification of combined process systems. SOUR and DHA of activated sludge andbiofilm of the combined process reactor showed a downward trend, biological activity isaffected by temperature and carbon source, and the sludge activity is proportional toorganic matter concentration in the environment.Through system flora diversity and similarity analysis,comparing biofilm diversityindex of each level of the activated sludge with the biofilm, diversity index of biofilm ishigher than the activated sludge, indicating that microbial populations in the biofilm aremore rich. Simultaneously, similarity of biofilm samples is significantly higher than thatof activated sludge, caused partly by higher diversity of the microbial flora in thebiofilm.Process combining Multi-level A/O with aerobic biofilm is an energy-saving, efficient and stable wastewater treatment process, it can be applied to new constructionand renovation projects, by adjusting the various operating parameters to achieve thebest conditions, and improving water quality.更多还原