城市污水处理厂颗粒碳源回收及活性初沉系统作用机制研究

Based on the situation of carbon source shortage during sewage treatment process in cities of low carbon nitrogen ratio problem, this project is to calculate the material moving and energy moving by using CFD system, and analysis the sedimentations characteristics of matter in different water fluctuation and HRT. Based on the rules of flowing deformation for states-of-matter in traditional primary system, the program aimed to discuss the utilization of carbon source in input water and its loss during the whole system of sewage treatment, and also present the characteristics of granular microorganism for organics degradation and hydrolysis. Besides, the program is to discuss the quantity of carbon source in primary system, and comprehend the rules of carbon source and its multiplication in the whole system, as well as evaluating the recyclability of granular carbon source in primary system; the program also will be verified the ferment effect of primary sludge and the release potential of carbon source in primary system, analyzing the influence factors of carbon source release and recycle during primary sludge fermentation, as well as revealing the fermentation mechanism of primary sludge and microbial species distribution; The program will be improved the elutriation and fermentation of primary sewage, and innovated recycle model of carbon source, establishing the activated primary system tentatively, along with building the system of carbon source material balance, as well as improving the capacity of carbon source in primary system. In brief, the program will be realized the maximized utilization and multiplication of carbon source during sewage treatment process by continuous technological test, and will be provided sufficient technical support for carbon source reclamation and sewage reduction.

针对低碳氮比城市污水处理过程碳源不足的问题，借助计算流体动力学（CFD）分析初沉系统的物质流动和能量流动，解析不同水力波动和停留时间初沉系统物质沉降特性；依据传统初沉池物质相流变规律，分析污水处理厂进水碳源利用和传统初沉系统碳源流失状况，解析颗粒态慢速生物降解有机物水解转化特性，掌握初沉系统中碳源赋存状况，揭示系统中碳源禀赋规律，评价初沉系统颗粒碳源回收性能；探明初沉污泥发酵效果与碳源释放潜力，分析初沉污泥发酵碳源释放与回收影响因素，揭示初沉污泥发酵机制与微生物种群分布规律；完善初沉污泥碳源淘洗发酵机理，创新碳源原位回收利用模式，初步构建活性初沉系统，深度挖掘初沉系统碳源潜力，建立系统碳源物料平衡体系。基于以上研究成果，通过连续工艺试验实现城市污水处理过程内部碳源活性增殖和最大化利用。研究成果不仅在理论上有重要意义，而且对污水处理碳源高效回收利用以及污泥减量化资源化也将提供有力的技术支撑。

项目针对目前城市污水碳源含量不足以及传统初沉池中碳源流失影响污水脱氮除磷的问题，开展城市污水中颗粒态物质沉降性能与初沉池碳源的回收潜力研究。.实验研究结果表明，初沉池对污水中SS、TCOD的去除率分别为56.7±7.73%、43.71±5.42%，该部分颗粒物质的沉降是碳源流失的主要因素。对颗粒态物质的可生物降解性进行检测，结果表明污水中易生物降解有机物含量较低，仅占进水COD的13.1%，而慢速生物降解有机物占51.4%，由此可知，对污水中慢速生物降解有机物进行高效回收，并加速其向易生物降解有机物的转化可充分挖掘碳源的回收潜力。.本研究尝试构建了一种新型活性初沉池系统，组合搅拌淘洗和污泥发酵工艺，分别控制初沉池机械搅拌速率60 rad/min、污泥回流比5%~10%、污泥停留时间2天，研究结果表明，通过机械搅拌可有效减小污水中颗粒态物质的粒径，从而降低颗粒态物质的沉降速度，同时污泥发酵作用可显著提高污水中优质碳源（SCOD、VFA）的含量，增加了Bacteroidetes、Clostridium、Lachnospiraceae等功能性微生物种群的分布丰度，将该技术应用于西安市第四污水厂，对其初沉池进行改造，改造后初沉池出水中的SCOD和VFA分别提升了25~35%和55~65%，显著提升了脱氮除磷效果。