【作者】 胡琼；

【导师】 于晓华；

【作者基本信息】 北京交通大学 ， 市政工程， 2009， 硕士

【摘要】 磷是重要的矿产资源,在现有社会循环中,单向流动、不可再生,所以人类对磷的利用方式是不可持续的。如何从污水中回收磷,实现磷资源的可持续性利用的研究和实践受到水工业界、磷工业界和政府的高度重视。磷酸铵镁(MAP)结晶法和磷酸钙(CP)沉淀法是从污水中回收磷酸盐的两种主要方法。在回收磷的工艺体系中,pH值是影响两种方法回收磷的重要因素之一,而不同pH值条件下有机酸等对磷酸铵镁结晶反应和磷酸钙沉淀反应的影响复杂,尚未有明确机理对其作出解释。本实验根据实际养猪废水成分,配制废水,进行模拟实验,观察反应过程,测定反应后溶液中N、P、Ca、Mg指标,分析结晶、沉淀产物的结构、形态和成分,对比研究不同pH值条件下有机酸(除特殊说明外,文中有机酸指乙酸、丁二酸和柠檬酸)及其浓度对MAP结晶法和CP沉淀法回收磷的影响。实验室模拟养猪废水批次实验表明：1.乙酸、丁二酸和柠檬酸对MAP结晶沉淀反应和CP沉淀反应中磷的最终去除率都有一定的影响,而且这种影响依次增强,氮、镁、钙的去除率与磷的去除率变化趋势基本一致,但变化趋势较平缓。2.乙酸、丁二酸和柠檬酸对MAP结晶沉淀反应达到平衡的时间影响依次增大,不同pH值条件、不同种类和浓度的有机酸对MAP结晶沉淀反应达到平衡的时间影响效果不同；而这些有机酸浓度条件对CP沉淀反应反应速率没有明显影响。3.乙酸、丁二酸和柠檬酸对MAP结晶沉淀反应产物的形态的影响依次增大,乙酸和柠檬酸对MAP晶体产物的结构、成分没有影响,丁二酸对结晶产物的结构有一定影响,但对其成分影响不大；除柠檬酸对CP沉淀产物的结构和成分有一定的影响以外,有机酸对CP沉淀反应沉淀产物的形态、结构、成分没有明显影响。4.不同的pH值、有机酸和酸浓度条件下,MAP晶体在钢铁等材料上吸附固着性能远大于CP沉淀在钢铁等材料上的吸附固着性能；而且同等条件下,MAP的沉降性能要好于CP的沉降性能。更多还原

【Abstract】 Phosphate is a very important mineral resource which obeys the rule of unidirectional flow in the material cycle process and it is non-renewable, however, the existing phosphate using method is unsustainable, so the research and practice for using phosphate in a sustainable way and recovering phosphate from wastewater draws high attention of the water industry, the phosphate industry and the government. Magnesium ammonium phosphate (MAP) crystallization and calcium phosphate (CP) precipitation recovering phosphate from wastewater are two main phosphate recovery technologies.The system’s pH value is one of the most important factors of the MAP and CP technologies, however, the systematic influence mechanisms of organic acid on the MAP and CP reaction under different pH values is unknown. Batches of simulation experiments were carried out by preparing wastewater with reference to the composition of the swine wastewater, the experiments’phenomena were observed, the N, P, Ca/Mg indexes were measured and the crystallization/precipitation products were analyzed, so as to compare the different influences of organic acids(acetate, succinate and citric in order) under different pH values on phosphate recovery by MAP crystallization and CP precipitation.Batches of synthetic swine wastewater experiments’results showed that:1. Solution organic acid concentration has some influence on the final removal efficiency of phosphate, and the influence increases accordingly, the final removal efficiency trend of the reaction system’s N/Mg/Ca keeps consistent with that of phosphate while more gentle.2. Solution organic acid concentration has some influence on the MAP crystallization equilibrium time and the influence increases accordingly, the influence on the MAP crystallization equilibrium time changes under different pH values and organic acid concentrations. However, it has little influence on the CP precipitation reaction rate.3. Solution organic acid concentration has increasing influence on the product morphology of MAP crystallization; succinate acid has some influence on the products texture while acetate acid and citric acid have little influence both on their texture and components. However, organic acid concentration has almost no influence on the product morphology, texture and components of CP precipitation except that citric acid has a little effects on the product texture and components.4. It was also observed that the MAP’s adsorption capacity on steel materials (under different pH values, organic acids and their concentration) is much better than that of CP under the same reaction conditions, and it is also embodied on the settling ability of these two products.更多还原