【作者】 田文德；

【导师】 李伟光；

【作者基本信息】 哈尔滨工业大学 ， 市政工程， 2013， 博士

【摘要】 过量富磷污水排入收纳受体已经被公认为是引起水体富营养化最重要的原因，随着日益严格的国家城市污水排放标准，磷的去除备受关注。从经济高效、节能环保的角度出发，生物除磷无疑是最佳的选择，不但可以节省大量的化学除磷药品消耗，同时也避免了经化学处理后污泥的二次污染，最重要的是生物法具有可持续性。而我国现有的多数污水处理厂仅靠生物除磷已经难以达到最新排放标准中较严格的出水磷浓度（＜0.5mg/L），尤其是目前很多城市污水中碳源不足，污水中C、N、P的比例严重失调，很难实现同时除磷脱氮的目的，鉴于此，寻求一种能在此环境下具有高效、低耗的生物除磷技术迫在眉睫，而反硝化除磷技术似乎提供了这样的可能性，然而工程上的应用甚少。本研究以反硝化除磷理论为基础，在A/O工艺的基础上通过添加两个选择器开发了两级生物选择反硝化除磷脱氮工艺（BBSNP工艺），解决了传统A/O和A²O工艺中污泥回流携带的硝酸盐对厌氧释磷的影响，通过缺氧区反硝化除磷菌的一碳两用解决了同时脱氮除磷碳源不足的问题，并且可有效控制污泥膨胀的发生。本文系统的研究了BBSNP工艺的常温和低温下处理实际城市生活污水的反硝化除磷脱氮效能，并采用FISH和DGGE等分子生物学手段跟踪了系统不同时期的菌群结构及其多样性，分析了主要功能菌群结构和同期处理效果之间的动态关联，并考察了BBSNP工艺运行的主要影响因素。结果表明：BBSNP最适宜的运行参数为污泥回流比100%、混合液回流比150%、硝化液回流比200%、DO1.0¹.5mg/L；常温下BBSNP工艺对低C/N比的城市污水处理效果较好，平均COD、氨氮和总磷的去除率分别为89%、90%和97%，出水可达到我国《城镇污水处理厂污染物排放标准》的一级A标准，而低温时COD和磷的去除效果较好，但脱氮效果较差；缺氧池中COD浓度在不超过50mg/L的情况下，不会引起普通的反硝化细菌与DPAO竞争，而且缺氧段硝酸盐氮量和缺氧吸磷量呈较好的线性关系，平均每消耗1mg NO₃^--N约吸收1.8mg TP，此参数可作为BBSNP系统反硝化除磷的一个重要参数。鉴于BBSNP工艺中主要的除磷菌为DPAO，因此本研究深入研究了DPAO在厌氧/缺氧和厌氧/好氧环境下的除磷特性、主要影响因素、竞争规律及其代谢特征。研究结果表明：乙酸为碳源时，DPAO在厌氧/缺氧环境下的反硝化除磷是通过PAO I、 PAO II和DGAO合作实现的，表现为PAO I和DGAO可以把硝酸盐还原为亚硝酸盐， PAO II可以利用亚硝酸盐为电子受体反硝化吸磷，而PAO I可同时利用硝酸盐和亚硝酸盐进行反硝化吸磷；Mg/Ca摩尔比对厌氧/缺氧环境下DPAO污泥EPS凝胶的形成影响较大，当Mg/Ca摩尔比≥5.0时，EPS凝胶受到严重破坏不能为聚磷菌提供较好的载体，从而导致除磷效果恶化；不同温度厌氧/好氧环境下Accumulibacter子群内部的竞争不影响系统的除磷效果，而且高度富集Accumulibacter的反应器中厌氧P/HAc比明显低于PAO模型中的比值, PAO模型有待修正；低温不但可以抑制GAO的生长，也可在短期范围内抑制PAO II的繁殖，但长期运行下PAOII比PAOI更具有竞争优势，且低温下污泥中较高的藻酸盐类EPS使污泥呈形态规则、粒径较大、机械强度很强的颗粒污泥；无论污泥中聚磷是否受限，PAO II厌氧环境下都可显现GAO的代谢特征，好氧环境下只表现为PAO的代谢特征； PAOI在厌氧和好氧环境下都不能表现为GAO的代谢特征，而是保持PAO的代谢特征。更多还原

【Abstract】 Excessive phosphorus-rich waste water discharged into the river has beenconsidered to be the most important reason to cause―eutrophication‖, withincreasingly stringent discharge standards of national urban sewage, phosphorusremoval was highly concerned. From cost-effective, energy saving andenvironmental friendly point of views, biological phosphorus removal is the bestoption, since not only it can save the consumption of considerable chemicals, butalso can avoid the secondary contamination of the chemical sludge, expectially itpossess biological sustainability. However, the majority of our existing waste watertreatment plants can’t achieve the latest phosphorus discharge standard （＜0.5mg/L）.In particular, a lot of urban waste water characteristic with inadequate carboncource, resulting in the imbalance of C, N and P, thus it is different to achievesimultaneous nitrogen and phosphorus removal. Considering this, it is most pressingmatter of the moment to explore a high efficiency, low consumption biologicalphosphorus removal technology, luckly denitrifying dephosphatation technologyseemingly could offer the possibility though marginal engineering applications.On the basis of the denitrifying dephosphatation theory and A/O process,Bi-Bio-Selector for Nitrogen and Phosphorus removal process （BBSNP process）was developed. It can effectively solve the effect of nitrate in recycled sludge onanaerobic phosphorus release, and achieve simultaneous nitrogen and phosphorusremoval through denitrifying phosphorus accumulating organisms （DPAO）so-called―dual use of the carbon source‖. Moreover, this process can effectivelycontrol sludge bulking.In this study, denitrifying phosphorus and nitrogen removal performance ofBBSNP process was systematically studied with real urban wastewater at room andlow temperatures, the population distribution and microbial diversity of differentperiods were traced by molecular biology methods（FISH and DGGE）, dynamicassociation between the main functional bacterium was evaluated and the mainrunning factors were also studied. The results show that the most suitable operatingparameters in BBSNP process were100%of SRT,150%of mixed liquor recycle ratio,200%of nitrified liquor recycle ratio and DO of1.0¹.5mg/L; the COD,nitrogen and phosphorus removal efficiency of BBSNP process treating low C/Nwastewater at room temperature was89%、90%and97%, respectively, which canmeet the Grade A standards of urban sewage treatment plant emission standards（GB18918-2002）. However, nitrogen removal peformance was highly influenced bylow temperature. In addition, less than50mg/L of anoxic COD concentration didnot cause the competition between ordinary denitrifying bacteria and DPAO, anoxicnitrate and anoxic P-uptake have a good linearship,1mg NO₃^--N consumptioncorresponding to1.8mg TP absorbtion, which can be used as one of the importantparameter in BBSNP system.The main phosphorus accumulating organisms in BBSNP process are DPAO,Hence, phosphorus removal characteristics, main influencing factors, competitionrules, sludge characteristic and metabolic stoichiometry of DPAO were furtherinvestigated in anaerobic/anoxic and anaerobic/aerobic environments. Theexperimental results show that anoxic denitrifying dephosphatation inanaerobic/anoxic environment contributed by the cooperation of PAO I, PAOII andDGAO when acetate as carbon source, where PAO I and DGAO reduced nitrate tonitrite, thus both PAO I and PAO II can use nitrite as electron acceptor of anoxicP-uptake, PAO I also can directly utilize nitrate as well. Mg/Ca molar ratios havesignificant impact on the formation of EPS gel, when the molar ratio of Mg/Ca≥5.0,the sludge can not provide a good carrier for the growth of DPAO/PAO since EPSgel formation has been severely damaged, resulting in the deterioration ofphosphorus removal. Under both room and low temperature, the competitionbetween Accumulibacter subclades do not influence the phosphorus removalefficiency, however, the anaerobic P/HAc ratios in so highly enrichedAccumulibacter cultures are significantly lower than in PAO models,suggesting thePAO model should be modified. In addition，low temperature have potentiality tosuppress the proliferation of GAO, and to some extent inhibit PAO II undershort-term conditions, while PAOII have a competitive advantage than PAOI underlong-term conditions. The granule sludge in low temperatue produced considerableamount of alginate-like EPS, which makes the gradule sludge regular morphology,big particle size and stronger mechanical strength. Regardless poly-phosphate is limited or not, PAO II can behave as GAO metabolism anaerobically and behave asPAO metabolism aerobically, but PAO I always behave PAO metabolism （not GAOmetabolism） under both anaerobic and aerobic conditions.更多还原