산처리에 의한 정수슬러지 감량화

Abstract

The acidic treatment of waterworks sludge released organic materials as well as inorganics such as Al, Fe and Mn. Through solubilization as mentioned above, the content of suspended solids reduced by 18% at final pH 3.5. It also increased the thickening efficiency and dewaterability of sludge. However overdosing of H2SO4 made dewaterability deteriorated. It showed that the optimal condition of acidic treatment be as follows; 5.5㎖ dose of H2SO4(97%)/ sludge, final pH 3.5 and reaction time 15minutes. Under these conditions, reduction efficiencies of sludge through thickening and dewatering were 57% and 92.2% respectively and then 7.8% of raw sludge released as cake compared to 10.5% without acidic pre-treatment. Therefore, mass of dewatered cake decreased by 26% through acidic treatment. Water content of dewatered cake was reduced from 71% to 62% due to this treatment. The changes of sludge properties including particle size, zeta-potential and bound water by acidic treatment appear to be important keys in assesment of sludge dewaterability improved.