基于信号分子与铁偶联调控下的污泥厌氧释磷机制及以蓝铁矿回收磷技术研究

As a non-renewable resource, the storage of phosphorus is quite limited. Wastewater treatment plants (WWTPs) is one of the most important convergences for phosphorus. Thus, the effective strategy to recover and reutilize pAs a non-renewable resource, the storage of phosphorus is quite limited. Wastewater treatment plants (WWTPs) is one of the most important convergences for phosphorus. Thus, the effective strategy to recover and reutilize phosphorus from sewage/sludge has been widely concerned. However, the key influencing factors and the mechanism of phosphorus release during anaerobic digestion are not quite clear, and also the efficient approach for the phosphorus recovery needs to be further studied. Therefore, the aim of this study is to investigate the effects of key signal molecules, which could regulate the microbial metabolic behavior by quorum sensing effects, on the phosphorus release from sludge during anaerobic digestion by analyzing the variations of signal molecules. Then the microbial community, especially the structure and abundance of phosphorus accumulating bacteria was determined via high-throughput sequencing. The approaches of metagenomics and proteomics are also employed to disclose the regulating mechanisms of signal molecules and iron on the phosphorus release from sludge during anaerobic digestion. Combined with the analysis of the changes in the multivalent iron system to reveal the correlation effect of signal molecules on the surface charge of PAOs, and the mechanism under the coupling regulation. Finally, a new method for rapid separation and efficient recovery of phosphorus through the formation of vivianite is proposed. The key factors and the related mechanisms involved in vivianite formation are illustrated in details. The study provides a new insight to improve the phosphorus release from sludge during anaerobic digestion and simultaneously realize the sustainable utilization of phosphorus, which merited a high academic value and practical significance.

磷作为一种非再生资源，其储藏量极其有限，污水处理厂是自然界中磷循环中转的重要地之一。如何实现污水/污泥中磷的高效回收以实现其可持续利用已广受关注。然而目前有关污泥厌氧消化释磷的影响因素及作用机理尚不明晰，磷的高效回收技术仍有待进一步研究。因此，本项目拟首先通过对污泥厌氧消化系统中关键信号分子（通过群感效应调控微生物的代谢行为）的分析和检测，同时借助高通量测序对聚磷菌种群结构和丰度进行分析；借助宏基因组学和蛋白组学等技术手段，从分子生物学等角度解析厌氧释磷机理，结合多价态铁系的变化分析，进而揭示信号分子对于聚磷菌表面电荷变化的关联效应以及多价态的铁在其变化过程的作用机制与偶联调控方法；通过探究蓝铁矿生成的影响因素及机制，创建快速分离与高效回收磷的新方法。本项目基于污泥厌氧消化释磷控制体系及蓝铁矿磷回收方法研究，对实现磷的永续利用具有十分重要的理论意义和实际应用价值。

利用厌氧消化同步回收剩余污泥中的磷，既有利于磷资源的回收利用，也可增强厌氧消化性能，降低污水/污泥处理成本，但是目前对于基于磷回收为主要目标的厌氧消化释磷机理、控制尚不清楚。本项目首先考察了以蓝铁矿形式回收磷的关键影响因素；考虑到蓝铁矿生成需要大量的铁和磷，是制约其生成的关键影响因素，因此在此基础上研究了厌氧发酵过程中铁和磷释放的主要影响因素和作用机制，接着探索了餐厨垃圾调质对污泥厌氧发酵回收蓝铁矿的影响，进一步探讨了铁和磷释放与挥发性脂肪酸（VFAs）生成的作用机制，最后在此基础上通过长期共发酵实验，利用高通量测序技术和宏基因组分析对于反应过程中微生物群落结构和功能基因变化进行解析，从微生物和基因层面探究FeCl3和餐厨垃圾的协同作用机制。.研究结果表明，pH是影响蓝铁矿形成的主要因素，温度的变化对于蓝铁矿的形成基本没有影响，形成蓝铁矿的最佳条件为Fe/P摩尔比为1.5，pH范围为6.0-9.0，初始PO43-浓度应大于5 mg/L。向剩余污泥厌氧发酵过程中投加FeCl3相比投加铁粉更容易促进Fe和P的释放，其中投加FeCl3以及控制pH为3的反应器释放效果最佳，剩余污泥中分别有78.81%的Fe2+和85.69%的PO43-释放到上清液中。异化金属还原菌Clostridiaceae（40.25%）是FeCl3-pH3反应器中的主要细菌，在诱导铁还原形成Fe2+中起关键作用，从而促进了Fe2+和PO43-的大量释放。剩余污泥中超过82.60%的磷可以通过投加FeCl3和酸性厌氧发酵的方式进行蓝铁矿磷回收。在长期共发酵试验中，在投加餐厨垃圾比例为30%、投加Fe/P=1.5的FeCl3以及不控制pH值条件下，Fe2+（831.32 mg/L）和PO43-（260.43 mg/L）释放效能最好，VFAs（7894 mgCOD/L）产量最高。从蓝铁矿回收的结果来看，回收沉淀物呈蓝绿色，晶体呈分叉状，回收的沉淀物中其主要成分（95.23%）为蓝铁矿。.通过项目的实施，明确了蓝铁矿形成的关键影响因素，解析了剩余污泥厌氧发酵过程中磷释放的途径，探究了污泥厌氧发酵回收蓝铁矿的作用机制，揭示了餐厨垃圾调质对污泥厌氧发酵同步高效回收蓝铁矿和 VFAs 的作用机理。该研究成果为厌氧消化过程回收磷的基础研究及污水处理系统的资源化提供了科学依据和技术支撑。