城市污水磷的高度去除并资源化中，磷的化学沉淀与活性污泥间的相互作用及优化调控研究

Biological phosphorus removal combined with chemical phosphate precipitation will inevitably become the course of phosphorus high efficient removal and simultaneous reclamation in municipal wastewater treatment plant in our country in the future due to the growing strict regulation on effluent discharge from municipal wastewater treatment plant and the increasing attention attracted by the potential value of phosphorus in the wastewater. Although process of chemical phosphorus deprivation from surplus sludge in BNR system，chemical phosphorus precipitation in tertiary treatment and Phostrip has been developed overseas aimed for high efficient phosphorus removal，it is not known very well about the mutual constraint and promotion of chemical phosphorus fixation and microbe in activated sludge，as well as how to reclaim the phosphate from wastewater to the greatest extent based on chemical phosphate precipitation applied as driving force, and biological phosphate release, luxury uptake as key point. In this project, AO system，A2O system, oxidization ditch and SBR in lab-scale will be applied to investigate the interaction of chemical phosphate precipitation using ferric salt and aluminum salt from bulk liquid and phosphorus enriched slurry sludge on biological system in activated sludge. With different phosphorus deprivation，the metabolism of phosphorus accumulation organism, sludge settlebility and activation，bacteria community, the removal of organic and nutrient substance, effect of chemical phosphate precipitation reagent adding on biological nitrogen removal will be monitored and investigated. The effects of feedback of microbial metabolism and their community on water quality and chemical phosphate removal will also be observed. As a result, we will find out the interaction of chemical phosphate precipitation and activated sludge, and propose some key controlling factors and operation parameters for optimization of the two processes that can supply some guide lines for the design and operation of municipal wastewater treatment plant in the future.

随着排放标准提高及人们对城市污水中磷的潜在价值的日益重视，生物-化学联合除磷工艺将成为我国城市污水处理厂磷的高度去除并实现污水中磷资源化回收的必然选择。尽管国外针对磷的高度去除已开发出污泥化学脱磷、深度处理化学除磷和phostrip等工艺，但对化学磷固定与活性污泥微生物间的相互制约与促进作用，如何能以化学除磷为驱动，以生物释磷与超量摄磷为核心，来最大限度实现磷回收等问题，尚无明确的答案。本课题采用AO、A2O、氧化沟和SBR实验装置，拟研究铁剂和铝剂对污水和高含磷污泥分别进行化学除磷时，磷的化学去除与生物系统间的相互作用。主要考察不同化学磷剥夺、残留化学除磷剂和不溶性磷酸盐对聚磷菌代谢、污泥性能、活性污泥菌群结构、系统对有机物去除和生物脱氮等的影响；微生物代谢和生态结构反馈对水质和磷的化学去除的影响。旨在揭示相互间的作用规律，明确优化调控参数，为我国污水处理厂设计和运行提供理论指导。

目前我国城市污水处理厂普遍采用的生物除磷+深度化学除磷工艺中，污水中的磷主要是通过排出高含磷污泥来实现的。面对日益匮乏的磷资源，这一做法是不可持续的。因此，采用主流生物除磷结合侧流化学联合除磷工艺来高度去除磷并回收污水中的磷资源，就具有明显的优势。但目前对侧流化学磷回收与主流活性污泥微生物之间的相互作用尚了解不多，如何实现化学除磷为驱动、生物释磷与超量摄磷为核心的最大限度磷回收等问题尚无明确的答案。.课题采用A2O和SBR两种实验装置，研究了侧流磷的化学去除与生物系统间的相互作用。.研究表明，（1）高比例的侧流化学磷回收，形成了对PAO的磷化学剥夺，造成了污泥中PAO占比减少，导致了生物除磷能力减弱，又反过来减少了化学磷的可回收量。在已经建立起良好生物除磷的系统中，对不超过入流量30%的厌氧氧段上清液进行化学磷回收（采用铁盐）下，侧流化学磷回收易于进行，短时内对后续生物除磷不会造成不利影响，但长期下还是会降低生物除磷能力。化学磷回收比率越低，这种不良影响就越轻微，甚至还会对生物除磷产生正向的促进作用；（2）生物除磷产生的富含磷污泥难以直接厌氧释磷，不宜对回流污泥实施侧流化学除磷；（3）化学磷沉淀后几个mg/L的残留铁剂对生物系统的影响较小。但长期积累化学不溶性盐类，会对污泥活性产生一定不利影响；（4）暂停侧流化学磷回收后，生物系统可以很快恢复活性，因此可以根据系统实际，灵活采用连续侧流化学磷回收或者间歇性化学磷回收。.课题研究对生物-化学联合除磷回收磷资源的城市污水处理厂工程的设计及运行提供了重要参考。