污水生物脱氮工艺有机物分配模式及机理研究

Nitrogen is mainly removed by biological aerobic/anoxic process for municipal sewage treatment. However, the lack of carbon source in municipal sewage limits the denitrification process and results in a low removal efficiency of total nitrogen. Thus, in this study, a new gradient utilization process of the different forms of the organic matters in wastewater during the biological nitrogen removal process will be developed and discussed. First, the particulate organic matters and dissolved organic matters will be flocculated /adsorbed by activated sludge, and then these Nitrogen is mainly removed by biological aerobic/anoxic process for municipal sewage treatment. However, the lack of carbon source in municipal sewage limits the denitrification process and results in a low removal efficiency of total nitrogen. Thus, in this study, a new gradient utilization process of the different forms of the organic matters in wastewater during the biological nitrogen removal process will be developed and discussed. First, the particulate organic matters and dissolved organic matters will be flocculated/adsorbed by activated sludge, and then these particulate organic matters are converted to dissolve organic matters for denitrification by ultrasound or hydrolysis acidification techniques. The effects of process parameters will be studied and the mechanisms of gradient utilization of organic matters will be discussed. Based on the analysis of the mass flow of organic matters, the regulatory mechanism of the priority utilization of organic matters in wastewater as the carbon source during denitrafication will be in-depth studied to improve the nitrogen removal efficiency and reduce the cost particulate organic matters are converted to dissolve organic matters for denitrification by ultrasound or hydrolysis acidification techniques. The effects of process parameters will be studied and the mechanisms of gradient utilization of organic matters will be discussed. Based on the analysis of the mass flow of organic matters, the regulatory mechanism of the priority utilization of organic matters in wastewater as the carbon source during denitrafication will be in-depth studied to improve the nitrogen removal efficiency and reduce the cost of wastewater treatment. The research topics include: (1) the hydrolysis acidification process of particulate organic matters; (2) the design of hydrolysis acidification reactor and species analysis of the hydrolysis acidification products; (3) the development of a continuous flow reactor for biological nitrogen removal researching; (4) the relationship between the dynamic changes of the microbial communities structure and the reactor performances; (5) the optimization of distribution mode of organic matters in the biological nitrogen removal system. The results of this study will provide a new technology and scientific basis to solve the widespread problem in China ? the lack of carbon source in municipal sewage for denitrification.

生物法是目前城市污水中氮的主要脱除方法，但我国城市污水普遍存在碳源不足的问题。本课题旨在研究污水中不同形态有机物在生物脱氮系统中实现梯级利用的有机物分配模式及其机理，探讨利用活性污泥的絮凝吸附作用对污水中颗粒态有机物和溶解性有机物进行有效分离，并采用超声、水解酸化等措施强化颗粒态有机物转变为可作为反硝化碳源的溶解性有机物的新方法，在物质流分析的基础上，深入研究污水中有机物优先用作反硝化碳源的分配调控机制，以提高污水生物脱氮系统出水水质并降低污水处理成本。主要研究内容包括：(1)污水中有机物形态分析及颗粒态有机物强化水解酸化过程研究；(2)颗粒态有机物水解反应器运行策略及水解酸化产物形态分析；(3)污水中有机物梯级利用反硝化系统构建及过程优化；(4)不同运行策略下反应器内微生物群落结构及演替变化研究；(5)有机物在生物脱氮系统中分配模式的模型建立及优化。研究成果能够为解决我国普遍存在的污水脱

在目前污水生物反硝化脱氮过程中，碳源不足是脱氮效率不高的主要原因，我国许多城市污水厂都面临此问题，成为地方减排的难点之一。为了不增加成本，本研究通过水解酸化将絮凝吸附污泥中的有机物释放出来，增强颗粒态有机物向溶解态的转变，减少其他过程中有机物的消耗（包括有机物转化为剩余污泥），可提高BNR过程中有机物的总利用率，从而有效提高脱氮效率。本项目通过对生物絮凝污泥进行常规水解酸化，发现有机物在水解时间为6h时即可充分释放出来。比较了初沉污泥、剩余污泥和絮凝污泥的水解酸化效果，得出絮凝污泥是水解酸化获取碳源最佳底泥选择。温度为35℃时，不但可以为脱氮除磷系统提供较多的SCOD，而且又可避免系统氮、磷负荷过高。利用Eastman模式对絮凝污泥水解酸化动力学模式进行研究，确定了水解速率常数kh的取值，为实验中设计水解池水力停留时间提供参考。构建连续流生物脱氮装置并进行污水生物脱氮研究，以生物絮凝吸附工艺出水为生物脱氮系统的进水，在前置反硝化池以生物絮凝吸附工艺出水中溶解性有机物作为反硝化碳源，利用水解酸化产物作为二级反硝化池的反硝化碳源；在物质流分析的基础上，优化有机物在生物脱氮系统中的分配模式，建立水解酸化反应器和生物脱氮系统的耦合机制，并建立污水处理系统的物料平衡分析方法。生物絮凝-水解酸化-A2/O组合系统在脱氮的同时也伴随着除磷，综合脱氮及反硝化除磷来考虑，最佳污泥回流比和最佳混合液回流比分别为300%和80%。该研究提高了污水中有机物作为碳源的利用率，可减少污水处理系统中氧的需要量，可有效提高污水生物脱氮系统出水水质并降低污水处理成本，为低 C/N 比污水的生物脱氮提供新的理论和技术支持。该资助项目成果已在刊物发表论文8篇，其中SCI论文3篇。