磷酸铵镁法处理模拟氮磷污水的研究
发布时间：2019-05-16 21:56
【摘要】：氮磷的大量排放一方面导致水体污染,另一方面导致磷资源的流失。磷酸铵镁法作为目前从废水中回收氮磷最有效的途径之一,得到了广泛的研究。磷酸铵镁法应用于污水处理的限制因素主要包括两点,一是投加镁源而增加的处理费用;二是由于磷酸铵镁法是物化方法,对氮磷浓度较低的废水处理效果较差。如何提高磷酸铵镁法对较低浓度氮磷废水的处理效果是目前研究的难点和关键。本文在分别研究了Mg Cl2·6H2O溶液、Mg SO4溶液、Mg O固体和(Mg CO3)4·Mg(OH)2·5 H2O固体作为外加镁源所需要的最佳反应条件的基础上,考察了磷酸铵镁法用于去除高氮低磷污水中的正磷酸盐的可行性,同时综合考虑处理效果和经济因素得出最佳的镁源;重点研发了用于磷酸铵镁法脱氮除磷的一体化流化床反应器,在研究流化床反应器的最佳运行参数的基础上,通过实验比较验证了流化床反应器采用磷酸铵镁法对低浓度氮磷污水去除效果的强化效能,研究得出如下主要结论:(1)单因素实验结果表明,Mg Cl2·6H2O溶液和(Mg CO3)4·Mg(OH)2·5H2O固体作为最好的可溶性镁源和难溶性镁源,最佳的反应条件分别是p H=10.5,搅拌30min,搅拌速度为100r/min,n(Mg)∶n(N)=1.1,n(P)∶n(N)=1.0;p H=8,搅拌1.5h,搅拌速度为120r/min,n(Mg)∶n(N)=1.3,n(P)∶n(N)=1.0;对应的氨氮、正磷酸盐的去除率分别为82%、92%和80%、84%。(2)氨氮和正磷酸盐的进水浓度分别为100 mg/L和70 mg/L是磷酸铵镁法所需要的较小浓度,分别投加Mg Cl2·6H2O溶液和(Mg CO3)4·Mg(OH)2·5H2O固体作为镁源,并在两种镁源各自的最佳控制条件下进行反应,氨氮和正磷酸盐的去除率分别为30.5%、80.6%和25.0%、73.3%。虽然投加Mg Cl2·6H2O溶液的氮磷去除效果略好于投加碱式碳酸镁固体,但投加Mg Cl2·6H2O溶液会造成二次污染,并且需要更高的p H值等因素,选择碱式碳酸镁作为最佳镁源。实验结果也证明以磷酸铵镁的形式去除高氮低磷污水中的正磷酸盐,是可行的。(3)以(Mg CO3)4·Mg(OH)2·5 H2O固体为镁源,设计p H值、氨氮浓度、正磷酸盐浓度的三因素三水平正交实验,结果表明,影响氮磷去除率的因素的主次顺序为:p H值正磷酸盐浓度氨氮浓度,综合考虑氨氮和正磷酸盐的去除率,选择p H=9,N=200mg/L,P=50mg/L做为正交实验的最优组合。(4)以(Mg CO3)4·Mg(OH)2·5 H2O固体为镁源,用一体化流化床反应器处理模拟氮磷污水,实验结果表明HRT越小,正磷酸盐的去除率越大,随着反应时间的推移,不同HRT对应的正磷酸盐的去除率逐渐接近,选择HRT=10min做为流化床反应器的最佳水力停留时间。(5)与实验室小试实验相比,虽然由于流化床反应器中水流的作用破坏后期形成的较大磷酸铵镁晶粒,导致流化床反应器对氮磷去除率的优势只体现在在反应开始后的前30分钟,但是流化床反应器取样位置越低,颗粒粒径越大、沉降性能越好,并且都大于同条件下烧杯对比实验的颗粒粒径。
[Abstract]:On the one hand, the discharge of nitrogen and phosphorus leads to water pollution, on the other hand, it leads to the loss of phosphorus resources. Magnesium ammonium phosphate process, as one of the most effective ways to recover nitrogen and phosphorus from wastewater, has been widely studied. The limiting factors of magnesium ammonium phosphate process in wastewater treatment mainly include two points, one is the increased cost of adding magnesium source, the other is that magnesium ammonium phosphate method is a physicochemical method, and the effect of magnesium ammonium phosphate method on wastewater treatment with low concentration of nitrogen and phosphorus is poor. How to improve the treatment effect of magnesium ammonium phosphate process on low concentration nitrogen and phosphorus wastewater is the difficulty and key of current research. In this paper, the optimum reaction conditions for Mg Cl2 路6H2O solution, Mg SO4 solution, Mg O solid and (Mg CO3) 4 Mg (OH) 2 路5H2O solid as added magnesium source have been studied. The feasibility of removing orthophosphate from high nitrogen and low phosphorus wastewater by magnesium ammonium phosphate method was investigated, and the best magnesium source was obtained by considering the treatment effect and economic factors. An integrated fluidized bed reactor for nitrogen and phosphorus removal by magnesium ammonium phosphate method was developed. On the basis of studying the optimum operating parameters of the fluidized bed reactor, The enhancement efficiency of ammonium magnesium phosphate method for the removal of low concentration nitrogen and phosphorus wastewater in fluidized bed reactor was verified by experiments. The main conclusions are as follows: (1) the single factor experimental results show that, Mg Cl2 路6H2O solution and (Mg CO3) 4 Mg (OH) 2 路5H2O solid were the best soluble magnesium and insoluble magnesium sources. The optimum reaction conditions were pH 10.5, stirring for 30 min and stirring speed of 100 r / min, respectively. N (Mg): n (N) = 1.1, n (P): n (N) = 1.0; PH 鈮，
本文编号：2478581
[Abstract]:On the one hand, the discharge of nitrogen and phosphorus leads to water pollution, on the other hand, it leads to the loss of phosphorus resources. Magnesium ammonium phosphate process, as one of the most effective ways to recover nitrogen and phosphorus from wastewater, has been widely studied. The limiting factors of magnesium ammonium phosphate process in wastewater treatment mainly include two points, one is the increased cost of adding magnesium source, the other is that magnesium ammonium phosphate method is a physicochemical method, and the effect of magnesium ammonium phosphate method on wastewater treatment with low concentration of nitrogen and phosphorus is poor. How to improve the treatment effect of magnesium ammonium phosphate process on low concentration nitrogen and phosphorus wastewater is the difficulty and key of current research. In this paper, the optimum reaction conditions for Mg Cl2 路6H2O solution, Mg SO4 solution, Mg O solid and (Mg CO3) 4 Mg (OH) 2 路5H2O solid as added magnesium source have been studied. The feasibility of removing orthophosphate from high nitrogen and low phosphorus wastewater by magnesium ammonium phosphate method was investigated, and the best magnesium source was obtained by considering the treatment effect and economic factors. An integrated fluidized bed reactor for nitrogen and phosphorus removal by magnesium ammonium phosphate method was developed. On the basis of studying the optimum operating parameters of the fluidized bed reactor, The enhancement efficiency of ammonium magnesium phosphate method for the removal of low concentration nitrogen and phosphorus wastewater in fluidized bed reactor was verified by experiments. The main conclusions are as follows: (1) the single factor experimental results show that, Mg Cl2 路6H2O solution and (Mg CO3) 4 Mg (OH) 2 路5H2O solid were the best soluble magnesium and insoluble magnesium sources. The optimum reaction conditions were pH 10.5, stirring for 30 min and stirring speed of 100 r / min, respectively. N (Mg): n (N) = 1.1, n (P): n (N) = 1.0; PH 鈮，
本文编号：2478581
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