음식물쓰레기의 호기성 퇴비화 전과 후의 세척에 따른 염분도와 퇴비화효율 비교

Comparison of Salinity and Composting Efficiency by Washing before and after Aerobic Composting of Food Wastes

This study was performed to evaluate the effects of washing food wastes before aerobic composting on temperature, pH and salinity, and the effects of washing after composting on salinity of sample mixtures. Weight ratios of food wastes to water in washing were 1:0(Control), 1:1(W-1), 1:2(W-2), 1:3(W-3) and 1:0(N-4), respectively. Ratios of food wastes to wood chips in reactor of Control, W-1, W-2, W-3 and N-1 were 5kg:0L, 5kg:5L, 5kg:5L, 5kg:5L and 5kg:5L, respectively. Reactors were operated for 24 days with 1 hour stirring by 1 rpm and 2 hours of forced aeration per day. The increase in the ratio of water to food wastes resulted in the increase of the maximum reaction temperature and the shortening of the high temperature reaction period. The increase in the ratio of water to food wastes also resulted in faster reaching to the lowest pH and then to the steady state of pH 9.0. The final salinities of Control, N-1, W-1, W-2 and W-3 were 1.04%, 0.92%, 0.78%, 0.64% and 0.53%, respectively. The salinities of the N-1 samples which were washed by the weight ratios (water:N-1) of 1:1, 2:1 and 3:1 after composting were 0.72%, 0.61% and 0.51%, respectively. Therefore, washing food wastes before aerobic composting is more efficient method than that after aerobic composting.