【作者】 王冰；

【导师】 韩洪军；

【作者基本信息】 哈尔滨工业大学 ， 市政工程， 2011， 博士

【摘要】 分段进水脱氮工艺是近年来国内外学者较为关注的一项新兴的污水处理技术。本研究将生物流化床的理念引入到分段进水脱氮工艺中,将分段进水工艺与生物膜法相结合,使该系统具备高效脱氮、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,并通过理论分析、试验研究及模型推导等手段,对流化床分段进水工艺的脱氮效能进行深入的研究。该工艺所具有的较高的脱氮效能及简单灵活的操作方式,使其适宜作为对原有污水处理厂的提标改造及对脱氮效能有较高要求的新污水处理厂的建造方案。本研究通过对四级三相式生物流化床分段进水工艺的启动及运行,得出该工艺具有较好的脱氮效能及对有机物的去除能力,并通过试验证明了在相同进水水质和运行条件下,四级三相式生物流化床分段进水工艺的脱氮效能要高于流化床A/O工艺。在等比例进水条件下,改变进水碳氮比、水力停留时间、碳源类型及污泥回流比,系统均表现出较好的脱氮效能,TN去除率最高可达88.9%,且好氧区出现了明显的同步硝化反硝化现象,并从进水方式和生物膜结合的角度分析了该工艺的脱氮机理。在考察流量分配对于系统脱氮效能的影响时,通过理论推导,得出了碳氮比与最佳进水分流比的关系,计算出当碳氮比为4、6、8、10、12时,对应的最佳进水分流比分别为0.59、0.88、1.18、1.47和1.76,并且计算出各最佳进水分流比对应的理论脱氮率。从理论和试验角度,分析了采用最佳进水分流比在系统脱氮效能上体现的优势。通过试验验证了进水分流比对于系统脱氮效能、硝化及反硝化性能的影响。不同进水分流比条件下,系统对于氨氮的去除率均达到93.4%以上。随着进水分流比的增加,系统所能达到的总氮去除率也随之增加,最高可达92.6%。在不同进水分流比条件下,好氧区硝化速率的变化趋势是沿程降低的,且进水分流比越大,这种降低的趋势越快。在进水分流比较低情况下,反硝化反应会受到碳源的影响,在进水分流比较高情况下,出水硝酸盐氮主要来自于最末段进水。因此采用较高的进水分流比利于提高系统的脱氮效能。在四级三相式生物流化床分段进水工艺影响因素的分析中,还考察了缺好氧区容积比例、污泥回流比、溶解氧浓度及填料填充率这几种因素。试验结果表明: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增强系统反硝化性能,从而提高TN去除率;污泥回流比对于系统脱氮效能的影响并不显著,从节能低碳的角度考虑,50%的回流比较为合适;将好氧区溶解氧浓度控制在1.5～2.0mg/L,可以在保证脱氮效能的前提下,减弱溶解氧对反硝化作用的影响;兼顾运行效果和填料的一次性投加费用,30%的填充率是比较合适的。采用显微镜及扫描电镜技术,观察系统启动及正式运行阶段活性污泥及生物膜的微生物组成和形态特征,并分析了反应器内的微生物特性及微生物固定化机理。四级三相式生物流化床分段进水工艺的生物相较为丰富,该系统表现出较高的生物活性,且污泥产率仅在0.136～0.311kgMLSS/kgCOD之间变化,低于常规活性污泥法工艺。最后,以经典活性污泥法动力学模型为基础,对四级三相式生物流化床分段进水工艺的底物降解动力学、硝化和反硝化动力学进行研究;并建立了同步硝化反硝化动力学模型;提出并推导了附着微生物停留时间的表达式。综合以上研究成果,可以将四级三相式生物流化床分段进水工艺运用到实际工程的新建及改造中去,并通过调节各运行参数以实现系统的最佳工况,在投入最小的运营及改造成本条件下,使出水水质达到国家排放标准。更多还原

【Abstract】 Step-feed nitrogen removal process, as a new sewage treatment technology, was concerned by scholars domestically and abroad in recent years. The idea of step-feed nitrogen removal process combined with biological fluidized bed was introduced in this study. In fact, there were many advantages, such as high nitrogen removal efficiency, saving the return facility, no external carbon source, improving the system resistance and increasing the concentration of activated sludge. The nitrogen removal mechanism and nitrogen removal efficiency of fluidized bed step feed process were studied in a deep and scientific way. This process could be used in the reconstruction project of original wastewater treatment plant and construction of new plant because of its high nitrogen removal performance and simple and flexible operation.The removal efficiency of three-phase biological fluidized bed step-feed process was studied. This process had good removal ability of nitrogen and organism. As a result, the experiment result showed that when the influent water quality and the operating conditions were equivalent, the denitrification efficiency of the three-phase biological fluidized bed with four step-feed process was higher than the fluidized bed A/O process. When the influent proportion of each segment was equal, the system showed a well nitrogen removal efficiency with the change of influent C/N ratio, HRT, carbon type and sludge return ratio. The removal rate of TN reached up to 88.9%. It showed that the simultaneous nitrification and denitrification phenomenon happened in the aerobic zone. The nitrogen removal mechanism was studied from the way of influent and biofilm.The influence of flow distribution on nitrogen removal performance was studied. Through theoretical derivation, the relationship of C/N radio and the best influent split ratio was concluded. When the C/N rate was 4, 6, 8, 10 and 12, the best influent split ratio was 0.59, 0.88, 1.18, 1.47 and 1.76. The theoretical nitrogen removal rate under best influent split ratio was calculated. The advantages of best influent split ratio was analyzed from the theoretical and experimental point of view. The influence of influent split ratio on nitrogen removal, nitrification, denitrification and nitrification rate of aerobic zone was verified. Under different influent split ratio, ammonia nitrogen removal rate could reach to 93.4% or more. With the influent split ratio increased, the TN removal rate also increased, up to 92.6%. Under different influent split ratios, the nitrification rate was lower along the trend, and the greater the influent split ratio was, the faster the nitrification rate decreased. Under low influent split ratio, denitrification would be affected by carbon source. On the other hand, under influent split ratio, the effluent nitrate-nitrogen was mainly from the last aerobic zone. Therefore, the application of higher influent split ratio helped to improve the denitrification efficiency. Influence factors such as volume ratio, sludge return ratio, DO concentration and carriers filling rate were also investigated. The results showed that the flow distribution played a significant role in nitrogen removal performance. When the best influent split ratio was adopted, denitrification could be enhanced and TN removal efficiency could be improved by maximizing the share volume of anoxic zone. Sludge return ratio was not significant for the nitrogen removal performance of the system. Based on the perspective of low-carbon energy, 50% was appropriate. DO concentration in aerobic zone was controlled in 1.5～2.0mg/L to avoid denitrification environment being destroyed. Take the operating results and one-time investment cost into consideration, 30% of the filling ratio was more appropriate.By using microscopy and SEM technology, Microbial composition and morphology of activated sludge and biofilm during start-up stage and formal running stage. Microbial characteristic and mechanism of microbial immobilization were analyzed. The micro-organisms of the process showed good treatment effect and strong resistance to shock load. The sludge production was in the range of 0.136～0.311kgMLSS/kgCOD, that was lower than which of conventional activated sludge process.Finally, based on the classic dynamic model of activated sludge, substrate hydrolysis kinetics, nitrification kinetics and denitrification kinetics of three-phase biological fluidized bed step-feed process were studied. Dynamic model of SND was established. Attachment microorganism retention time was proposed and its expression was derived.Based on the above results, three-phase biological fluidized bed step-feed technology can be applied to actual projects. System operational parameters was adjusted to achieve the best working conditions. Under the condition of minimum cost, make sure the effluent quality meet the national emission standards.更多还原