본 연구에서는 실험실 규모의 혐기성 소화 실험을 통하여 고온산발효를 거친 음식물찌꺼기 산발효액과 하수슬러지의 적정 혼합비와 유기물 부하율에 따른 반응조 운전특성을 분석하여 실제 플랜트에 적용가능성을 검토하여 얻은 결론은 다음과 같다. 음식물지꺼기 고온 산발효액과 하수슬러지를 혼합하여 반연속식으로 혐기성 소화실험을 실시한 결과 유기물 부하율 3.3 gVS/L.d(혼합비 1:1)에서 최적인 것으로 평가되었는데, 이때 SCOD 제거효율은 평균 74.2%, VS 제거효율은 73.6%, 주입된 VS당 생성된 가스량은 $0.440{ell}/g;Vs_{add}.d$였으며 평균 메탄 함량은 66.5%로 나타났다. 이는 기존에 음식물찌꺼기를 하수처리장의 중온 소화조에서 처리할 때의 유기물 부하보다 높아 효율성, 경제성에서 유리한 것으로 판단되었다.
This study has been conducted for the process of food wastes disposal using surplus capacity of established sewage treatment plant by co-digestion of fermented food wastes and sewage sludge after thermophilic acid fermentation of food wastes. The co-digestion of thermophilic acid fermented food wastes and sewage sludge was performed by semi-continous method in mesophilic anaerobic digestion reactor. It showed great digestion efficiency as the average SCOD and VS removal efficiency in organic loading rate 3.30g VS/L.d. were 74.2% and 73.6%, and the gas production rate and average methane content were 0.440 L/g $VS_{add}.d$ and 66.5%, respectively. Based on the results of this study, the co-digestion of thermophilic acid fermented food wastes and sewage sludge in sewage treatment plant is able to improve treatment efficiency of anaerobic digestion reactor and to dispose food wastes simultaneously, and was proved excellent economical efficiency comparing with any other treatment methods.
