【作者】 鲍林林；

【导师】 张杰；

【作者基本信息】 哈尔滨工业大学 ， 市政工程， 2008， 博士

【摘要】 建立社会用水的健康循环是解决我国水危机、实现水资源可持续利用的根本途径。在实现水系统健康循环的基本策略中,建立城市范畴上的再生水供应系统是重中之重。寻求经济、可行的再生水生产技术是我国水处理领域面临的首要问题。近年来反硝化除磷理论的提出给我们提供了新的思路和视角,以其“一碳两用”、“节能环保”的优势越来越受到人们的关注。针对这一现状,本课题以实际生活污水为处理对象,对反硝化聚磷菌的特性及反硝化除磷工艺展开深入研究。A2N双污泥同步除磷脱氮工艺是反硝化除磷理论的典型工艺。本研究以实验室内现有的A2N双污泥工艺系统为基础,对反硝化聚磷菌的生物特性进行深入研究,同时针对A2N双污泥工艺中存在的问题,提出一种改进工艺,并考察了改进工艺对生活污水的处理效能,以期寻求一种经济、可行的再生水生产技术。通过A2N双污泥系统的微生物研究发现:反硝化聚磷污泥和普通好氧聚磷污泥在性状上极为相似,内源物质聚β羟基丁酸和聚磷在厌氧/缺氧的交替过程中有着和厌氧/好氧相同的变化规律;系统中同时存在着两类聚磷菌,一类是可以同时以氧和硝酸氮为电子受体的聚磷菌,另一类是只能以氧为电子受体的聚磷菌。为了进一步研究反硝化聚磷菌的特性与生物多样性,对以氧、硝酸盐氮和亚硝酸盐氮为电子受体的生物除磷系统进行对比研究。研究发现,亚硝酸盐氮对聚磷菌好氧和缺氧吸磷的抑制浓度分别为0.88mgN/gVSS和6.72 mgN/gVSS;在以硝酸盐氮为电子受体的反硝化除磷基础上采用逐渐增加亚硝酸氮浓度的方法驯化聚磷污泥,可以增加污泥对亚硝酸盐氮的适应性,并最终可以选择亚硝酸氮作为唯一电子受体,但其除磷效率远低于以氧和硝酸盐氮为电子受体的除磷系统,同时发现除磷系统生物群落结构随着电子受体的变化而改变,聚磷菌种类具有多样性。通过一系列的试验对反硝化吸磷过程中的一些重要影响因子进行了考察。碳源类型对反硝化除磷影响较大。碳源的长期试验结果表明,以丙酸钠和乙酸钠为碳源的除磷系统除磷效率相当,以葡萄糖作为唯一碳源,造成了除磷系统的崩溃。DGGE分析结果显示,以乙酸钠和丙酸钠为碳源的系统生物群落结构极为相似,以葡萄糖作为唯一碳源造成了除磷系统生物群落结构的彻底改变,以Micropruina glycogenica为代表的典型聚糖菌在系统中富集起来。反硝化聚磷菌属于低温耐冷菌,低温的短期冲击对缺氧吸磷的影响并不大,10℃~20℃为反硝化除磷的高效段。增大污泥系统的MLSS,可以提高缺氧初期的反硝化吸磷速度和最终的吸磷总量,但单位污泥的吸磷量没有提高反而减小。针对A2N工艺运行中存在的问题,提出改进型A2N工艺,考察了改进工艺对生活污水的处理效能,并对影响系统运行的主要因素进行了探讨。在进水C/N比较低的情况下(3.5~5.5),改进A2N双污泥系统对COD、NH4+-N、TN和TP的平均去除率分别为80.93%、97.44%、81.46%和68.2%。其中COD、NH4+-N和TN的去除效果比较理想,达到国家《城镇污水厂污染物排放标准》(GB18918-2002)一级A排放标准,达到了回用水要求。系统对TP的去除有待于进一步提高,出水平均值为0.94 mg/L,达到一级B排放标准。和传统的A2N双污泥反硝化除磷工艺相比,改进A2N工艺流程更为简洁,在NH4+-N和TN的去除上更具优势,在大多数时间内出水NH4+-N甚至可以达到零排放,由于好气滤柱生物膜内微环境引起的自养脱氮效应,在硝化液回流比一定的情况下,TN的去除率稳定而且高效。但由于改进的A2N工艺除磷效率抗冲击性较差,再加上好气硝化滤池内“二次释磷”现象的影响,改进的A2N工艺的除磷效率低于传统的A2N工艺。更多还原

【Abstract】 Establishment of a healthy social cycle for water utilization is a fundamental way to solve water crisis and achieve sustainable use of water resources in China. According to the strategy of the healthy water cycle, the establishment of the reclaimed water supply system in urban areas is the top priority. The most important issue we faced is to seek an economic and feasible renewable water production technology for wastewater treatment. In recent years the theory of denitrifying phosphorus removal provides us some new ideas and perspectives and attracts more and more people’s attention, with its advantage of "dual-use carbon" and "energy conservation and environmental protection". In response to this status, this study focus on the characteristics of denitrifying phosphate-accumulating organisms and the performance of denitrifying phosphorus removal process for treating municipal sewage.A2N process is a typical process of the theory of denitrifying phosphorus removal.In this study, the characteristics of denitrifying phosphate-accumulating organisms was investigated. At the same time, for the existing problems of the A2N process, an improved process was proposed and its performance for treating municipal sewage was investigated in order to seek an economic and feasible technoloty for the renewable wastewater production.Microbial study on A2N process showed that the character and variation of intracellular substances PHB(Poly-β-Hydroxybutyric acid) and Poly-p(Poly-phosphate) were similiar between denitrifying phosphorus accumulating sludge and common aerobic phosphorus accumulating sludge. Two kinds of phosphorus accumulating organisms (PAOs), one used O2 as electron acceptor, the other used O2 or NO3--N, were both found in the anoxic tank of A2N process.To study the characteristic and diversity of denitrifying phosphorus accumulating organisms (DPAOs), three phosphorus removal reactors with different electron acceptors of O2, NO3--N and NO2--N were carried out respecitively. The results showed that nitrite inhibits both aerobic and anoxic phosphorus uptake, and the threshold for aerobic and anoxic phosphate uptake were 0.88mgN/gVSS, 6.72 mgN/gVSS, respectively. With a stepwise increasing of NO2--N concentration in the influent, DPAOs were gradually accommodated to utilize NO2--N as electron acceptor, but its phosphorus removal efficiency was lower than that of O2 and NO3--N as electron acceptors. The results of DGGE targeting 16SrRNA gene indicated a significant shift in microbial community with different electron acceptor conditions.Furthermore, batch experiments were carried out to study the factors affecting the denitrifying phosphorus removal. Carbon sources had a great effect on phosphorus removal. Long-term experiments showed that propionate-fed system had similar phosphorus removal efficiency with acetate-fed system, when glucose was used as the sole carbon source, it would result in the deterioration of the phosphorus removal system. DGGE analysis showed that propionate-fed system had similar biological community structure with acetate-fed system, glucose as the sole carbon source caused the biological community structure changed radically and a novel glycogen accumulating organisms (GAOs), Micropruina glycogenica have proliferated. DPAOs were low-temperature-resistant bacteria, short-term temperature changes had little effect on denitrifying phosphorus removal. With the increase of MLSS, the quantity and rate of denitrifying phosphorus removal increased, while the specific phosphorous uptake quantity decreased.Long-term experiments showed that modified A2N process was applicable for low C/N wastewater treatment. When the influent C/N ratio ranged among 3.5~5.5, the mean removal efficiency of COD、NH4+-N、TN and TP were 80.93%、97.44%、81.46% and 68.2%, respectively. The COD、NH4+-N and TN removal were excellent in the modified A2N process, which met the standards of urban wastewater treatment plant pollutant discharge (GB18918-2002) - level A discharge standards, and achieved the reclaimed water demand. The mean final effluent TP concentration was 0.94 mg/L,achieved level B discharge standards, and the TP removal efficiency could be further improved.As compared with the traditional A2N process, the modified A2N process was simpler and more efficient on NH4+-N and TN removal. NH4 +-N could even achieve zero discharge at most of the time. When the nitrified recycle ratio was constant, TN removal rate was stable and efficient because of the nitrogen loss in the biofilter. However, due to the poor stability and "the second phosphorus release" in the biofilter, the phosphorus removal efficiency in modified A2N process was lower than that of the former A2N process.更多还原