Study On Removal TP In Municipal Wastewater With CaF₂-CaCO₃

Phosphate in some industrial wastewater and municipal wasterwater is the main reason of eutrophication of reservoirs.How toå’¯er the phosphate has been the important task of protecting the waters.This Paper studied on the removal of phosphate in modal wasterwater and municipal wasterwater with analytically purificated fluorite and calcium carbonate.Fluorite- Calcium carbonate removed the phosphate from model wastewater effectively.The phase of Batch tests studied the effect on the quantity of Fluorite added,reactive time and the pH in inffluent.The results showed that when the quantity of fluorite was 0.84 gram per 100 millilitre,the concentration of total phosphate in inffluent was 10 mg/L,under pH 6-9 condition and within 20 minutes,the residual phosphate from effluence was belower limitation tested(0.02mg/L) and was less than National Wastewater Discharge Standard significantly,the efficiency rate of phosphate removal was more than 99%. The mechanism of phosphate removal included the precipitation and adsorption,where the former was main.Fluorite-Calcium carbonate was effective to remove the total phosphate from municipal wasterwater.Patch tests studied the effect on the amount of Fluorite added,Calcium Carbonate added,mixing rate to remove the efficiency of TP removal.When the quantity of Fluorite was 2.52g/L,mixing rate was between 180r/min and 280r/min,the quantity of Calcium Carbonate was between 9.00g and 18.00g,the TP in influent was under 20mg/L within 10 min,the TP in effluent reached below 1.0mg/L and the efficiency rate of phosphate removal was about 97%.The mechanism was composed of precipitation , adorption and some biologic action together.Column results of Fluorite-Calcium Carbonate in treating the municipal wastewater showed that they were effective to remove the phosphate fromwastewater.In early phases,the concentration of phosphate in in influent was very low,which was less than that of National Wastewater Discharge Standard and with the increase in the volumn of wasterwater treated,the efficiency in treating the wastewater went worse and worse.The quantity of fluorite added kept power relation with the volumn of wasterwater treated,the quantity of phosphate removal,the life of the test materals,the ratio of the quantity of Fluorite added and the quantity of phosphate remoral.For tester used,the best ritio of the mass of Fluorite,the mass of Calcium Carbonate and the mass of filter medium was 25.20(g):22.50(g):1000(g).The mechanism was involved of precipitation , adorption,fitration and some biologic action together.The residual amount of Fluorin was between 6mg/L and 7mg/L,during the static tests and during the dynamic tests. The residual amount of Fluorin was divided into three phases:(1) about 3mg/L in early time;(2)about 2.5mg/L in middle time;(3)about 1mg/L in late time.For discharge from municipal wastewater, the residual Fluorin had little effect on the water quality.It is an effective method to use the Fluorite-Calcium Carbonate in treating the wastewater with phosphate.The method is on initial phases studied now,which has an applicable sense to analyse the test results.