基于过程控制与种群优化解析连续流单污泥系统短程反硝化除磷的稳定机制

Compared with conventional biological phosphorus removal and denitrifying phosphorus removal，it is worth noting that more aeration energy and carbon source can be saved when denitrifying phosphorus removal is occurred using nitrite as electron acceptor. In recent years, the research of denitrifying phosphorus removal using nitrite as electron acceptor received the widespread attention, and there are many research results in reports. However, most research carried out using sequencing batch reactor treating synthetic wastewater and limited researchhas been performed in a continuous-flow system treating domestic wastewater. No evdience confirms that the nitrite type denitrifying phosphorus removal can be achieved in continuous flow system and it is short of research on the inhibiting mechanism of NO2--N on phosphous removal. In this project, a continuous-flow single sludge system will be adopted and the stabilization of denitrifying phosphorus removal using nitrite as electron acceptor will be investigated based on the lab-scale experiment. The effects of electron acceptor type on phosphate accumulating organisms will be investigated and the relationship between key parameters and microbial population structure will be established furthermore. The main innovation points are as follows: (1) Aim at the "real domestic wastewater""single-sldge"and "continuous flow system" , the reserch is a pioneering work and the research results will be of great significance on practical application; (2) AOB population will be accumulated and the short-cut denitrifying dephosphatation model will be established based on AOB polulation, the research method is different from previous studies. (3) To optimize the population, process control and biological control will be applied in this study at the same time. It is a novel control method.

与传统生物除磷及反硝化除磷相比，短程反硝化除磷可进一步节约碳源和曝气量，降低运行成本。但目前，大部分研究针对人工废水且采用序批式反应器或双污泥系统，连续流单污泥系统处理城市污水能否实现稳定的短程反硝化除磷，以及亚硝酸盐对除磷是否存在抑制以及抑制机理尚缺少研究，且研究方法也存在一定问题。.本研究拟通过实验室规模试验，采用生物控制的方法筛选优势菌种，在实现短程脱氮基础上，研究亚硝酸型反硝化除磷的实现机制，并建立控制参数变化规律同微生物种群变化的相关关系，以此构建稳定的、以功能菌群主导的短程反硝化除磷模式。主要特色与创新包括: ①以“实际生活污水”，“单污泥”“连续流工艺”为研究对象，属开创性研究，且更具实际意义；②筛选、富集AOB菌群，以AOB功能菌群诱导短程反硝化，并在此基础上实现短程反硝化除磷，不同于以往研究方法；③以种群优化为目的，过程控制与生物控制相结合，这是本项目的特色与重要创新。

为应对严重的水污染问题，污水排放标准越来越严格。污染物的深度去除，通常需要消耗大量的电能并经常性投加大量的化学药剂，这导致间接碳排放量巨大，环境效益降低，违背低碳可持续发展原则。短程脱氮与反硝化除磷是污水处理新工艺，在能源消耗上具有巨大优势，但连续流系统稳定实现短程硝化以及单污泥系统实现反硝化除磷均是目前污水处理领域的难题，两者的耦合也存在难以稳定控制的问题。.针对上述难题，课题采用过程控制与生物控制相结合的方式，针对实际生活污水，重点对短程硝化的稳定实现、短程硝化与反硝化除磷的耦合，以及短程反硝化除磷的种群结构与控制参数之间的相关关系进行研究，得到如下重要结论：（1）SBR实现短程脱氮的控制策略不完全适用于连续流，多点进水系统可通过生物强化或低DO过程控制系统协助实现NO2--N稳定积累。（2）改进型A2/O分段进水系统短程反硝化除磷率达52.8%；短程反硝化实现过程，AOB和DPAOs未受“竞争”菌群NOB和GAOs抑制，AOB和NOB以及PAOs、DPAOs和GAOs未表现出明显竞争和抑制关系，且均有增加趋势；改进系统添加填料，AOB数量和累积稳定性明显提高，短程反硝化除磷性能相应增强。（3）关于NO2--N抑制的研究表明，连续流系统抵抗NO2--N抑制的能力较SBR系统更强，系统在高NO2--N浓度时，DPAOs对NO2--N的耐受性更强，受到的影响比PAOs小；分段进水工艺的结构特性，其更容易实现AOB、NOB、PAOs和DPAOs的平衡共存，而菌种平衡有利于抵抗NO2--N抑制。.上述成果的特色和创新在于：（1）采用实际生活污水，与人工配水存在本质不同；在连续流系统实现短程反硝化除磷，国内外研究较少；（2）过程控制与生物控制结合是先进的控制理论和策略，其有利于功能菌群平衡生长，菌群相互竞争和抑制降低，系统稳定性增强；（3）对现有工艺进行改进，一定程度克服同步脱氮除磷矛盾，系统控制难度大大降低，性能显著提升，成果已形成工艺包可直接应用于实际工程。