Application Of Coal Fly Ash In Phosphate Removal Of Wastewater

Along with the country to environmental protection dynamic's enlargement,the standard'Wasterwater quality standards for discharge to municipal sewers' requires that the total phosphorus content of wastewater discharged into the urban pipe network should be less than 8 mg/L.The phosphorus content in the factory wastewater of a company(NCFC)is about 3 3mg/L.In order to meet the requirements of wastewater discharge standards,the wastewater needs to be treated with phosphorus removal.The power plant in NCFC currently produces more than seventy thousand tons of coal fly ash per annum,of which nearly thirty thousand tons coal fly ash are produced from cyclone furnaces,it contains more than 20%CaO,17.3%Al2O3 and 3.6%Fe2O3.In this present study,an attempt was made to remove phosphorus in wastewater which come from process condensate diluted concentrate and crude product tank dischargeby coal fly ash from cyclone furnace contained high CaO and Al2O3.The characteristics of phosphorus removal by coal fly ash were investigated,including the affection of temperature and time of reaction?initial pH?coal fly ash dosage.The results showed that:In the NCFC's wastewater,73%of the P comes from the process condensate,27%of the P from crude product tank discharge.There is a large amount of organophosphorus in waste water,mainly in the form of methyl phosphate and dimethyl phosphate,Soluble Orthophosphate in wastewater is only 31-35%of TP.NCFC's cyclone furnace coal fly ash is a very effective phosphorus removal agent,the phosphorus removal efficiencyof process condensate diluted concentrate and crude product tank discharge is over 80%.The phosphorus removal rate by coal fly ash depends on the initial pH,temperature and time of reaction,coal fly ash dosage.Experiments show that the initial pH in 6.0 to 6.6,reaction temperature in 55? reaction time is 1 hour,coal fly ash dosage of 10 g/100 ml,can remove 80%phosphorus in wastewater.On the basis of the experimental test,by controlling the reaction end point pH 9.0 to adjust the coal blues dosing quantity,and the reaction temperature of 55?,total phosphorus removal efficiency can reach above 85%.