化学沉淀法预处理高浓度氨氮废水的研究

【作者】 仝武刚；

【导师】 王继徽；

【作者基本信息】 湖南大学 ， 环境工程， 2002， 硕士

【摘要】 随着工农业的迅速发展，氨氮污染的来源越来越广泛，排放量也越来越大，除了生活污水、动物排泄物外，还有大量的工业废水，如合金废水、炼油废水，以及垃圾渗滤液中的氨氮污染日益严重，而氨氮是造成水体富营养化的重要原因。因此，经济有效地控制氨氮废水技术是环境工作者研究的重大课题。 生物脱氮技术是当前人们研究的热点，但其不足是微生物对外界环境要求高，不易操作，尤其是高浓度氨氮废水需要大量稀释才适合硝化菌生长。本文研究从化学处理角度来去除废水中的高浓度氨氮，就是在氨氮废水中加入镁盐和磷酸盐，它们与氨氮在一定条件下发生反应，生成磷酸镁铵，其溶度积很小，在水中以沉淀物形式存在，这种沉淀物含有氮、磷、镁等植物所需的营养元素，是一种价值比较高的缓释复合肥料。本文先采用化学沉淀法处理模拟高浓度氨氮废水，通过正交试验确定影响因素大小，并对其影响因子逐个分析，得出最佳反应条件：pH值为9.0～10.0，n（Mg）：n（N）：n（P）=（1.1～1.2）：1：1，此时氨氮去除率在90％以上，但溶液中还残留部分磷，并测定沉淀物中的N、P、Mg的百分含量分别为4.7％（以N计）、32.4％（以P₂O₅计）、18.0％（以MgO计）。然后用化学沉淀法处理锰制品厂的高浓度氨氮废水，得出最佳工艺条件：原水（NH₃—N浓度为2 100.0mg／L）在pH值为9.2～9.8，n（Mg）：n（N）：n（P）=（1.2～1.4）：1：1的反应条件下，氨氮去除率达到95％以上，沉淀物测定结果含氮（以N计）5.2％，含磷（以P₂O₅计）34.5％，含镁（以MgO计）19.4％。 研究结果表明：采用化学沉淀法去除废水中的高浓度氨氮技术可行，经济合理，具有推广应用价值。同时沉淀物磷酸镁铵（简称MAP）为有经济价值的缓释氮磷复合肥料。更多还原

【Abstract】 With the agriculture and industry development, the pollution sources of wastewater with ammonia nitrogen become more and more, arid does the amount of discharge, which are from all types of industrial wastewaters, such as, metallurgical plant wastewater and petroleum refinery plant wastewater and landfill leachate, besides domestic wastewater and animal excrement. The key reason of eutrophication is ammonia nitrogen. How to remove ammonia nitrogen from wastewater is an important problem for environment researchers.Most researchers attach importance on biodenitrification, but nitrifying bacteria needs a favorable environment, which is not easy to be controlled. Especially nitrifying bacteria can’t grow in the high strength ammonia nitrogen wastewater. It is studied in this paper how to remove high strength ammonia nitrogen from wastewater by chemical precipitation, that is, magnesium salt and phosphate salt are added into this kind of wastewater, and precipitation occurs at an optimal condition, to produce magnesium-ammonium-phosphate which is an insoluble compound and contains only three nutrients of phosphorus, nitrogen and magnesium. These nutrients are valuable to plants. It is introduced artificial wastewater with high strength ammonia nitrogen is treated by chemical precipitation in the first part of the research, which has several steps: firstly, the sequence of factors is determined by orthogonal experiment, secondly, the effects of the factors are analyzed, at last, ammonia nitrogen removal rate of artificial wastewater is above 90% at pH between 9 and 10, magnesium, ammonium and phosphate molar ratios of (1.1-1.2): 1:1. However, there is residual phosphate in the treated wastewater. The percentage of N, P, Mg in the precipitate are 4.7%(N), 32.4%(P2O5) and 18.0%(MgO) respectively. High strength ammonia nitrogen wastewater from manganese plant is treated by chemical precipitation in the second part. The result is that the removal rate of high strength ammonia nitrogen from wastewater is above 95% at the optimal precipitation condition which is pH between 9 and 10, magnesium, ammonium and phosphate molar ratios of (1.1-1.2):1:1. The percentage of N, P, Mg in the precipitate are 5.2%(N), 34.5% (P2O5) and 19.4%(MgO) respectively.The research shows that the technique removing high strength ammonia nitrogenfrom wastewater by chemical precipitation can be put into practice, and the precipitate is a composite fertilizer.更多还原