【作者】 杨杰；

【导师】 张杰； 李冬；

【作者基本信息】 北京工业大学 ， 土木工程， 2016， 硕士

【摘要】 水孕育了生命,是人类赖以生存的根本。我国是一个人均水资源缺乏的国家,加上工业的发展,城市化的推进,大量的氮、磷排入水体,水污染问题日趋严重。生活污水中的氮、磷元素是水体富营养化的主要元凶。传统生物脱氮除磷技术虽然对氮、磷有一定的去除能力,但是存在脱氮与除磷污泥龄的矛盾、能耗高、需要投加额外碳源、污泥产量高等诸多问题。反硝化除磷技术能够同步的去除氮和磷,从根本上解决了脱氮除磷的矛盾,与传统工艺相比,可减少30%的曝气量、50%的碳源消耗量、50%的污泥产量,适用于低C/N生活污水的处理。在现有的反硝化除磷技术中,在进水磷浓度较高时,去除能力低下,常需要借助化学除磷。本课题采用将缺氧后置的SBR反应器,通过控制曝气强度与时间,先在好氧段去除部分磷的同时进行硝化反应,再进行反硝化除磷,既保证了磷的高效去除,也保留了反硝化除磷技术的诸多优点。以污水厂二沉池污泥为接种污泥,先以短污泥龄驯化PAOs,再引入缺氧段,延长污泥龄,在39 d即可实现全程硝化-反硝化除磷,COD、TP、NH₄⁺-N、TN去除率分别为92.9%、98.4%、100%和87.6%。结果表明,C/N对系统氮磷去除有一定影响:C/N短暂的降低幅度不超过17.65%时,氮磷去除效率并没有明显变化;当超过33.3%时,脱氮除磷性能下降,但伴随着运行时间的延长,出水COD浓度减少,反硝化除磷菌（DPAOs）在PAOs比例也会提升,这在一定程度上弥补了DPAOs反硝化脱氮效率的下降。周期实验显示,pH值与DO可以作为厌氧释磷结束与周期结束的实时控制参数,大大缩短反应时间,降低曝气能耗。批次实验结果表明,以硝酸盐为电子受体的DPAOs占PAOs的比例在C/N=6与4时分别为67.3%与85.9%。为进一步提高系统的脱氮除磷能力,研究了短程硝化与以亚硝酸盐为电子受体反硝化除磷的实现及处理效果。结果表明,通过限氧条件下的排泥策略,可以实现常温低氨氮下的短程硝化与反硝化除磷,呈现出了良好的脱氮除磷效果,出水满足且部分优于《城镇污水处理厂污染物排放标准》（GB 18918-2002）一级A标准。批次实验显示,以亚硝酸盐为电子受体的反硝化除磷在总聚磷菌中的比例可达70%。研究发现,过长的缺氧反应时间会对磷的去除有负面影响,宜控制在亚硝酸盐反应完毕为止;曝气方式仅影响氮的去除,总曝气量不变,采取强度前高后低的曝气策略,控制适宜的曝气强度,可提高氮的去除效果。最后,考察了短程硝化-反硝化除磷系统处理实际生活污水的运行效能。结果表明,系统对COD、TP、NH₄⁺-N与TN表现出较好的去除性能,去除率分别能达到83.8%、94.6%、100%和79.1%。尽管可利用有机碳源有所减少,但DPAOs仍能保证系统污染物的去除,这适宜于低C/N生活污水的处理。研究发现,虽然实际生活污水水质条件复杂,限氧条件下的排泥策略依然可以维持稳定的短程硝化。更多还原

【Abstract】 Water gives birth to the life, and it is fundamental to the survival of humans. China is a country lack of water resources. With the development of industry and the propulsion of urbanization, a large amount of nitrogen and phosphorus is discharged into the water, the problem of water pollution becomes worse and worse. Nitrogen and phosphorus in sewage is the main culprit of eutrophication. Although the nitrogen and phosphorus removal in traditional biological technology can reach a certain level, there are some issues, such as the contradiction of the sludge age between nitrogen removal and phosphorus removal, high energy consumption, the need of adding additional carbon source, high sludge production, etc. Denitrifying phosphorus removal technology can remove nitrogen and phosphorus simultaneously, which solves the contradiction of the removal between denitrification and phosphorus fundamentally. Compared with the traditional process, denitrifying phosphorus removal technology can reduce 30% aeration rate, 50% carbon source consumption and 50% sludge production, and it is suitable for low influent carbon-nitrogen ratio（C/N） sewage treatment. However, for the current denitrifying phosphorus removal technology, the removal of phosphorus is very low when the influent phosphorus concentration is high. Then the help of chemical phosphorus removal is often needed. This subject adopted a post-anoxic SBR reactor. With the control of aeration intensity and time, we achieved denitrifying phosphorus removal in anoxic period by realizing nitration and removing some phosphorus in aerobic period, which maintained the advantages of the denitrifying phosphorus removal technology, and ensured the efficient removal of phosphorus.The sludge was taken from the second pond in sewage plant. The denitrifying phosphorus removal process was launched in 39 days by firstly shortening the SRT to enrich poly-phosphate accumulating organisms（PAOs）, and then extending the SRT and introducing the anoxic phase. COD, TP, NH₄⁺-N and TN removal efficiency were 92.9%, 98.4%, 100% and 87.6%, respectively. The results showed that the influent C/N affect nitrogen and phosphorus removal efficiency to some content. There was no obvious change on nitrogen and phosphorus removal efficiency when the decrease of C/N was below 17.65% in a short term. When it exceeded 33.3%, the system had a bad performance on both nitrogen and phosphorus removal, but in the long run, the effluent COD concentration fell, and the proportion of denitrifying phosphorus accumulating organisms（DPAOs） in PAOs increased, which supplemented the removal efficiency of decline to some extent. The cycle test indicated that p H and DO can be the real-time control parameters which decided whether the anaerobic phosphorus release and the cycle ended or not. The reaction time and energy consumption of aeration could be reduced significantly. Batch experiment indicated that the proportion of DPAOs with nitrate as electron acceptor in PAOs was 67.3% and 85.9% when C/N was 6 and 4, respectively.In order to further improve the ability of nitrogen and phosphorus removal efficiency, the realization of nitritation and denitrifying phosphorus removal by nitrite pathway was investigated. The results indicated that nitritation and denitrifying phosphorus removal in low concentration of ammonia water at normal temperature was established with the strategy which discharges sludge in the condition of limited oxygen. This system showed a good denitrifing phosphorus removal efficiency, the effluent meeted and partly exceeded the first class level A of Discharge standard of pollutants for municipal wastewater treatment plant（GB18918-2002）. According to the batch experiments, the ratio of DPAOs which took nitrite as electron acceptor in total PAOs could reach 70%. Studies indicated that overlong anoxic reaction time had negative effects on phosphorus removal, and it should be stopped when the nitrite was completely consumed. Aeration mode only affected the removal of nitrogen. With the adoption of the aeration strategy of higher at the beginning and then lower, and control of appropriate aeration intensity with total oxygen changeless, nitrogen removal efficiency could be improved.Finally, we investigated the efficiency of nitritation- denitrifying phosphorus removal system treating actual sewage. The results showed that the system showed a good performance of removing COD, TP and NH₄⁺-N and TN, whose removal rate could reach 83.8%, 94.6%, 100% and 79.1%, respectively. Although the available organic carbon source decreased, DPAOs still could guarantee the pollutant removal in the system, which was more suitable for low C/N sewage treatment. It was found that although the actual sewage water was complex, sludge discharge in condition of limited oxygen could still maintain the stability of nitritation.更多还原