음식폐기물 산발효액 내 존재하는 유기산은 산업 원료로 가치가 있으나 분리 비용이 높은 문제점이 있다. 본 연구에서는 저에너지 유기산분리를 위해 전기투석공정에서 산발효액 내 유기산의 이동현상과 운전조건 (전압, 희석율, pH) 간의 상관관계를 연구하였다. 아세트산과 부틸산으로 주로 구성된 음식물 산발효액 원액 (COD 기준 유기산 67.3 %) 을 실험실 규모 전기투석기를 사용하여 분리전압을 5 V ~ 12 V로 변화시켰을 때, 분리전압 8 V에서 최대 유기산 회수율 (COD 기준 89.4 %, 순도 86.8 %) 을 보였으며, 이 때 분리에 사용된 에너지는 0.286 kWh/kg-COD of VFAs로 나타났다. 전기투석과정에서 분자량 차이에 따른 유기산 간의 이동현상 차이는 발견되지 않았다.

Batch cultivations were performed to evaluate the influences of the initial pH condition on mesophilic and thermophilic acidogenic fermentation with food waste recycling wastewater. In both conditions of mesophilic and thermophilic fermentation, TVFAs production rates were maximized at the initial pH 7 condition as 0.15 and 0.23 g TVFAs/L·hr, respectively. And pH was also maintained stably between 6 and 7 during 72hr acidogenic cultivation at both conditions. However, predominant VFA components were different according to reaction temperature conditions. In mesophilic condition, propionic acid which has low conversion efficiency to methane was accumulated up to 1,348 mg/L while acetic and butyric acid were predominant in thermophilic condition. Therefore, thermophilic acidogenic fermentation was superior for the effective VFAs production than mesophilic condition. From the DGGE analysis, the band patterns were different according to the initial pH conditions but the correlations of the each band were increased in similar pH conditions. These results mean that microbial communities were certainly affected by the initial pH condition. Consequently, the adjustment of the initial pH to neutral region and thermophilic operation are needed to enhance acidogenic fermentation of food waste recycling wastewater.