基于磷酸盐还原体系的兼氧MBR气化除磷机制研究

Phosphorus is a kind of non-metallic mineral resource, which is difficult to regenerate. While the contradiction does exist all over the world caused by growing scarcity of phosphorus on the land and high levels of phosphorus lead to eutrophication in water. Traditional biological phosphorus removal which was achieved mainly through the discharge of phosphorus-rich sludge, not only increased the cost of sludge treatment, but hindered the recovery of phosphorus as well. Under this circumstances, another method, that is facultative gasification phosphorus removal based on phosphate deoxidation achieved qualitative transformation of phosphorus forms, reduction of phosphorus-rich sludge and resource of phosphorus-rich water. On one hand, Using the secondary cold trap enrichment, gas chromatography, grading continuous extraction, luciferase method and PCR-DGGE, study is focused on the energetic metabolism pathways and migration law of phosphorus during energetic metabolism under different substrate conditions, proving the phosphine release rule and conversion ways of phosphorus during phosphate deoxidation, and confirming the structure and physiological characteristics of microbial populations participating in the phosphate deoxidation under facultative condition in the facultative MBR. On the other hand, using the regulation of sludge self digestion on sludge characteristics and microbial metabolites, achieve phosphorus-rich sludge reduction and mitigation of membrane fouling processes. Exploring the mechanism of gasification phosphorus removal based on phosphate deoxidation in facultative MBR has significance for expansion of microbial phosphorus theory and achievement of ‘recovering’ phosphorus removal mode with low power consumption and high efficiency.

磷是一种难以再生的非金属矿资源，而全球范围内普遍存在着陆地磷矿产资源日益匮乏与水环境中磷含量过高而导致水体富营养化的矛盾。传统生物除磷主要通过富磷污泥排放实现磷的去除，不仅增加了污泥处理成本，更不利于磷的回收利用。基于磷酸盐还原体系的兼氧气化除磷实现了磷形态质的转化，同时实现了富磷污泥减量化和富磷污水资源化。利用二次冷阱富集、气相色谱、分级连续浸提、荧光素酶法、PCR-DGGE等分析检测手段，研究兼氧MBR系统在不同底物条件下的能量代谢途径及磷在能量代谢过程中的迁移规律，探明磷化氢的释放规律和磷酸盐还原过程中磷元素的转化途径，确定兼氧条件下参与磷酸盐还原反应的微生物种群结构及生理特性。利用污泥自消化对污泥特性和微生物代谢产物进行调控，实现富磷污泥减量化并减缓膜污染进程。探索基于磷酸盐还原体系的兼氧MBR气化除磷机制，对扩充微生物除磷理论，实现低能耗、高效率的“回收型”除磷模式具有重要意义。

全球范围内普遍存在着陆地磷矿产资源日益匮乏与水环境中磷含量过高而导致水体富营养化这一矛盾。将除磷过程由“去除型”向“回收型”转变，使富磷污水成为一种新型“磷矿”成为研究开发的重点。以磷酸盐还原为基础的“气化除磷”技术，是磷在污水处理中系统中从固态和液态向气态迁移转化的一种新途径。本课题以高浓度有机物高磷污水为研究对象，提出了基于兼氧条件下磷酸盐还原的污水除磷新技术，研究不同影响因素对系统的除磷性能的影响，基于试验数据探讨磷形态的转化途径以及磷化氢的产生机制，探讨了以气化除磷技术为基础的磷酸盐还原系统的微生物群落结构及作用机理。在无剩余污泥排放的条件下采用分步提升COD负荷的方式成功构建了兼氧MBR系统，在启动阶段第30天COD和TP去除率分别在92%和45%以上，菌种活性较高，系统运行稳定，反应器在正式运行阶段逐渐检测到磷化氢的生成，此时COD去除率可达到93.24%，TP的去除率可达到47.74%。对兼氧MBR系统正式运行30d后的磷平衡进行研究，系统中每天外源磷的去除量为227.6mg，系统共损失2333.13mg，30天磷化氢的总产量约为578.95 mg/L，大约是系统磷损失量的33%。通过测试分析，兼氧气化除磷系统的磷形态转化途径为Org-P→NaOH85-P→HCl-P→NaOH-P→BD-P→H2O-P。采用16SrRNA测序技术，分别在“门”和“种”分类学水平上研究气化除磷系统微生物群落结构。结合热力学综合分析推测磷酸盐还原系统可能的作用机理，系统通过PTS通路运输葡萄糖，磷酸盐和次磷酸盐代谢通路与细胞的跨膜运输是系统提供H2PO4-的途径，磷酸戊糖代谢通路为系统提供能量，磷脂酰肌醇信号系统与磷酸肌醇代谢通路为生成磷化氢提供了有利的胞内环境。兼氧MBR气化除磷工艺有效的改善了富磷污泥排放及由此产生的二次污染、污泥处理困难等不足，对于高浓度有机物高磷废水不仅有较好的除磷性能，而且降低了处理成本。将磷酸盐还原为PH3，可节约磷源。为新型生物除磷工艺的技术开发和工程实践提供了理论支撑和技术支持，具有重要的现实意义和良好的开发应用前景。