Study On Phosphorus Removal Effect Of Water Body In Mushroom Lake Reservoir Based On Electrochemistry

Phosphorus is an important factor in controlling eutrophication of water bodies.In recent years,the phosphorus content in Mushroom Lake body is seriously exceeded.As the phosphorus-containing sewage continuously enters the reservoir,it exceeds the self-purification capacity of the water body,and the water body is eutrophicated.This thesis selects the mushroom lake reservoir as the main research object,exploring the pollution status of the mushroom lake reservoir and the effect of electrochemical phosphorus removal,and explores the optimal level of electrochemical dephosphorization recovery of struvite according to the sediment generated during the experiment.Field sampling surveys were conducted from July 2017 to November 2017,and the detection values were analyzed,and the mushroom lake water was evaluated in combination with the survey data.In the laboratory,the effect of electrochemical phosphorus removal was simulated by simulating mushroom lake water,and the effects of current density,initial pH and electrode plate material on electrochemical phosphorus removal were investigated.Orthogonal experiments were designed to explore the optimal levels of phosphorus removal and recovery of struvite.The experimental mechanism and product analysis were carried out by XRD and SEM,and the optimal conditions obtained by the experiment were subjected to real wastewater phosphorus removal experiments.The main conclusions are as follows:(1)The results of Mushroom lake water quality evaluation showed that the comprehensive pollution index of Mushroom Lake body in 2012-2016 was greater than 2.0,which is seriously polluted.The 2013-2014 Mushroom Lake body was mildly eutrophic,and the eutrophication index of Mushroom Lake in 2016was greater than 70,and eutrophication was severe.(2)In the low-concentration phosphorus removal experiment,the aluminum plate and the magnesium plate are more suitable for the neutral and weakly alkaline water bodies;the iron electrode has a large adaptability to the pH value of the water body.At pH=3,the iron plate pair Phosphorus removal rate is 11%higher than that of aluminum plates and magnesium plates.Electrolysis at a current density of 10 mA/cm~2for 30 min,the removal rate of phosphorus by the three anode plates was more than 90%,but the phosphorus removal rate of the magnesium plate was higher than that of the aluminum plate and the iron plate by 4.7%and 2.7%,respectively.And within the electrolysis time of 20 min,the removal rate of phosphorus by the magnesium plate reached 94.8%.(3)In the high concentration phosphorus pollutant removal experiment,the phosphorus removal efficiency of the aluminum plate under acidic conditions is lower than that of the neutral and weakly alkaline water bodies;after the magnesium plate is electrolyzed to 30 minutes,at pH=3,pH=7 The phosphorus-containing water with pH=9 can achieve a removal rate of more than 90%.At pH=3,the removal rate of phosphorus by the iron plate is 6%higher than that of the aluminum plate.When the current density is 15mA/cm~2,the removal rate of phosphorus by the three plates can reach more than 95%,but within 30 min of electrolysis,the removal effect of phosphorus on the magnesium plate is obviously higher than that of the aluminum plate and the iron plate.(4)The removal mechanism of phosphorus by three kinds of plates mainly through electroflocculation,but in the process of removing high concentration of phosphorus from magnesium electrode,it is mainly electrochemical precipitation.A large amount of magnesium ammonium phosphate precipitated during the electrochemical precipitation process,achieving the purpose of recovering phosphorus.(5)The use of magnesium plate electrochemical dephosphorization to recover struvite,the results show that the optimal purity level of magnesium ammonium phosphate can be obtained by electrolysis for 120 min under the condition of voltage of 7 V and initial pH of 8;at the same time,the voltage is 7 V,initial The optimum phosphorus removal rate was obtained by electrolysis at pH 8 for 180 min.(6)Using magnesium electrode to carry out the actual wastewater experiment of mushroom lake,the experimental results show that after 30 minutes of electrolysis,the removal rate of phosphorus pollutants is over 90%,and it meets the second-order reaction kinetics.