Study On Struvite Precipitation And Electrocoagulation To Recyle The Coal Chemical Wastewater

Coal chemical wastewater has the characteristics of high concentration,high toxicity and complex composition.It is difficult to meet the national emission standards through simple treatment,but the recovery of coal chemical waste water is an effective way to solve the problem of non-compliance.Coal chemical cooling circulating water contains the main components of ammonia and COD.The purpose of this paper is to quickly and economically remove high concentrations of ammonia nitrogen and COD in the cooling circulating water,so that the wastewater can be reused.The research contentsare as follows:1.The optimum condition forming struvite.When the pH value was around 8.9,the molar ratio of P043-:NH4+:Mg2+ was 1.2:1:1,the time is 20min.The residual nitrogen and phosphorus in water are the lowest,and this method is affected by temperature litlle.when this method is used to treat coal chemical wastewater,ammonia nitrogen removal rate of up to 90%or more.2.Thermal decomposition of struvite was studied.When the struvite was heated under alkali conditions,the temperature was 85℃;the molar ratio of OH-:NH4+ was 1;and heated time was 1.5 hours.The rate of denitrification of struvite was 95%.When we put the pyrolysis product to the coal chemical water,the product can remove the ammonia nitrogen in the waste water again,Which can be recycled coal chemical wastewater.3.The coal chemical industry was electrolyzed by electrocoagulation method,and the COD was reduced by about 20%under the conditions of ionization density of 20 mMA·cm2 and electrolysis time of 20 min.At the same time,the reaction system In the concentration of P,to avoid the struvite in the pipeline precipitationThe combination of struvite and electrocoagulation in the treatment of coal chemical wastewater can effectively reduce the ammonia and COD,so the waste water can be recycled and the cost can be reduced.