유기성슬러지는 바이오가스를 생산할 수 있는 우수한 원료물질로서 선진국에서는 이를 이용한 에너지 생산이 급증하고 있다. 국내의 경우 음식물쓰레기, 가축분뇨 및 하수슬러지를 대상으로 하는 바이오가스 생산 및 공급을 상용화하는 단계에 있다. 하지만 산업폐기물의 경우 에너지 가용 잠재력은 많으나 활용이 미흡하고, 산업단지에서 발생하는 유기성슬러지를 비롯한 유기성 폐자원은 일부 대규모 사업장에서 자체 에너지화 등을 통해 발생된 폐기물을 활용하고 있으나 대부분의 중･소규모 사업장은 일정 비용을 지불하고 위탁처리하고 있는 실정이다. 일부 대규모 사업장에서 생산된 적은 양의 바이오가스는 자체적으로 소각 또는 보일러용으로만 사용하고 있어 잉여 가스를 이용한 수익창출이 어려운 실정이다. 유럽의 경우 단일 유기성폐기물을 대상으로 처리하기 보다는 생분해성 폐기물을 하나로 통합 관리하는 방안을 적극적으로 추진하고 있다. 따라서 본 연구에서는 유기성폐기물 해양투기 금지에 따른 대안 마련 및 유기성폐기물의 에너지화를 통한 국가 에너지원 확보를 위해 생활계의 음폐수와 사업장의 음료제조업(맥주제조업, 유가공제조업) 폐수처리슬러지를 대상으로 바이오가스화 가능성을 평가한 결과, BMP 실험의 경우 1:9, 3:7, 5:5 비율로 병합 처리한 경우 각각 약 233, 298, 344 CH4 mL/gVS의 메탄가스가 발생하였다. BMP 실험을 통해 생산된 메탄가스의 누적생산 곡선을 Modified Gompertz model과 first order kinetic model에 적용하여 추정한 결과, 메탄생성량은 Modified Gompertz model에서는 238.5, 302.3, 353.6 mL/gVS 발생하였고 first order kinetic model에서는 242.8, 312.5, 365.5mL/gVS로 음폐수와의 혼합비율이 증가할수록 높게 나타났으며, 최대 메탄생성속도의 경우 3:7비율에서 48.2 mL/gVS·day로 최대 메탄생성 속도를 보였다. first order kinetic model의 1차 반응속도상수 k값은 1:9, 3:7, 5:5 비율에 따라 0.32, 0.22, 0.08day-1 나타났다. 1차 반응속도 상수의 경우 음폐수의 혼합비율이 낮을수록 높게 나타났다. Modified Gompertz와 first order kinetic model 모두 실험결과를 잘 모사하였으며, 실험결과와 모의결과의 적합도를 나타내는 상관계수(R2)의 경우 0.92∼0.98으로 높은 상관성을 나타내었다.

According to the elementary analysis on organic wastes, the C/N ratio, a major condition for anaerobic digestion, is 5.40 to 9.23, except for food waste leachate (FWL). Defined by Tchobanoglous’ mathematical biogas prediction model, methane gas and biogas productions increased, depending on the mixing rate of FWL. Furthermore, anaerobic digestion both wastewater sludge and food waste leachate based on the right mixing ratio, increases methane gas productions compared to digesting wastewater sludge alone. In other words, co-anaerobic digestion is more likely to realize biogasification than single anaerobic digestion. We mix food waste leachate and wastewater sludge from the dairy and beer manufacturing industry by the proportion of 1 : 9, 3 : 7 and 5 : 5. It turns out that they produced 118, 175 and 223 CH4 mL/g VS in the dairy manufacturing and 176, 233 and 263 CH4 mL/g VS in beer manufacturing of methane gas. The result suggests that as the mixing rate of food waste leachate rises, the methane gas productions increases as well. And more methane gas is made when co-digesting wastewater sludge and food waste leachate based on the mixing ratio, rather than digesting only wastewater sludge alone. Modified Gompertz and Exponential Model describe the BMP test results that show how methane gas are produced from organic waste. According to the test, higher the mixing rate of food waste leachate is, higher the methane gas productions is. The mixing ratio of food waste leachate that produces the largest volume of methane gas is 1 : 9 for the dairy industries and 3 : 7 for brewery. Modified Gompertz model and Exponential model describe the test results very well. The correlation values (R2) that show how the results of model prediction and experiment are close is 0.920 to 0.996.

The objectives of this research was to evaluate the anaerobic digestibility of waste activated sludge (herein after WAS)and waste beverages (herein after WB) in beverages manufacturing industry using actual plant under various conditions.In this study, anaerobic digestion with WAS and WB were evaluated according to different operating conditions. As thebasis operating conditions for anaerobic digestion, the reaction temperature was controlled at 35 and hydraulic retentiontime 30 days. WAS and WB were mixed at the ratio of 1:0, 9:1, 8:2, 7:3, 5:5, Respectively. The organic loadingrate (herein after OLR) was maintained less than 0.5kgVS/m3·day. Biogas productivity in accordance with VS was fedat the each mixing ratio with WAS and WB was increased from 0.92Nm3/kg VSfeed to 1.28Nm3/kg VSfeed, except mixingratio 5:5 (0.19Nm3/kg VSfeed). Also Biogas productivity in accordance with VS was removed at the each mixing ratiowith WAS and WB was increased from 1.13Nm3/kg VSrem to 1.81Nm3/kg VSrem, except mixing ratio 5:5 (0.35Nm3/kg VSrem). It was judged that pH was reduced with WB addition. From the results, it was judged that anaerobic digestionusing WAS and WB could be feasible.

The objectives of this research was to evaluate the anaerobic digestibility of waste actizvated sludge (WAS) and wastebeverages in beverages manufacturing industry using BMP test under various conditions. Also, the effects of physical(ultrasonic) and biological (lactobacillus) solubilization process on anaerobic digestibility of WAS were thoroughlystudied. The soluble chemical oxygen demand (SCODCr)/total chemical oxygen demand (TCODCr) ratio of WAS was 0.15but the SCODCr/TCODCr ratio after solubilization was increased 17.5% by ultrasonic, 18.8% by lactobacillus respectively.The results of BMP test, methane gas productivity as mixing ratio of WAS and waste beverages were 156ml CH4/gCODCr,164ml CH4/gCODCr and 182ml CH4/g CODCr, respectively 9:1, 8:2, 7:3 before the solubilization of WAS. As themixing ratio of waste beverages increase, VFAs concentration and methane productivity was increased. Also, methanegas productivity as mixing ratio after the solubilization of WAS using ultrasonic and lactobacillus was increased3.3~11.3%, 11.1~15.2% respectively. From the results, it was judged that anaerobic digestion using WAS and wastebeverages could be feasible.