Research On Treatment And Resourcing Of High Concentration Phosphorous Wastewater In Bentazone Cyclic Complex

In recent years,the depletion of phosphorus resources,the phosphorus crisis and the eutrophication of water bodies have received more and more attention.The treatment technology of phosphorous wastewater has also begun to develop in the direction of phosphorus removal and phosphorus recovery.For enterprises,it is not only necessary to recover phosphorus from wastewater to meet national emission standards,but also to treat the recovered phosphorus and turn the recovered phosphorus from hazardous waste into available resources.Based on the phosphorus-containing wastewater from Bentazon production,the optimal conditions of phosphorus recovery by calcium chloride method,magnesium chloride method and struvite crystallization method were studied by single factor experiment At the same time,the effect of sodium chloride in waste water on phosphorus recovery by three methods was investigated.Although the methods of calcium chloride and magnesium chloride have better phosphorus recovery,but the precipitates obtained from phosphorus recovery have poor water solubility and low agricultural value,and the struvite crystallization method does not have very good phosphorus recovery,and the precipitates of ammonium magnesium phosphate are obtained It is a good slow-release fertilizer with good agricultural value.Therefore,the struvite crystallization method was selected to treat the phosphorus-containing wastewater of Bentazon,and the struvite crystallization method was optimized by adding calcium chloride.Then,the resource utilization of the treated sediment was studied.The main contents are as follows::(1)The results of simulated wastewater experiments show that the recovery of phosphorus by calcium chloride generally does not need to control the temperature.It can be carried out at room temperature.The equilibrium time of reaction is about 10 min.The experiment results in the best condition for recycling phosphorus by calcium chloride: p H is 10.0,The molar ratio of Ca2+:PO43-is 1.5:1.(2)The experimental results of simulated wastewater show that the recovery of phosphorus by magnesium chloride generally does not need to control the temperature.It can be carried out at room temperature.The equilibrium time of reaction is about 10 min.The experiment results in the best condition for recycling phosphorus by magnesium chloride: p H value is 9.5,The molar ratio of Mg2+:PO43-is 2:1.(3)The results of simulated wastewater experiments show that the recovery of phosphorus by Ammonium chloride and magnesium chloride method generally does not need to control the temperature.It can be carried out at room temperature.The equilibrium time of reaction is about 1min.The experiment results in the best condition for recycling phosphorus by Ammonium chloride and magnesium chloride method: p H value is 9.5,The molar ratio of Mg2+:NH4+:PO43-is 1.2:1:1.(4)Sodium chloride in wastewater will affect the effect of recycling phosphorus.When the concentration of sodium chloride is less than 1g/L,the calcium chloride method will produce the same ion effect,which is conducive to the recovery of phosphorus.When the concentration of sodium chloride is greater than 1g/L,Salt effect,As a result,the recovery rate of phosphorus decreased.Magnesium chloride and Ammonium chloride and magnesium chloride method produced only salt effect.(5)Under the optimum condition of phosphorus recovery rate,the waste water containing phosphorus from Bentazon can be treated by struvite crystallization method.The recovery rate of phosphorus can reach over 95%,but By adding calcium ion to optimize the crystallization process of struvite,the recovery of phosphorus can reach 99%.The optimum conditions for phosphorus recovery are: p H value is 9.5,the molar ratio of Mg2+:Ca2+:NH4+:PO43-is 1.2:0.1:1:1,the reaction time is 10 min,Generally do not need to control the temperature,room temperature can be carried out(6)by using struvite crystallization method and calcium chloride method to remove phosphorus,the sediment has been proved to have the function of weeding and promoting plant growth through pot experiment.