The sanitary landfill method not only stops leakage of leachate and landfill gas to the outside, it also prevents water or air ingress. These methods significantly reduce the environmental contamination of landfills. Recently, landfilling of organic wastes such as sewage sludge and food waste has been forbidden, and landfilled wastes are dried. In addition, the water supply from outside is blocked, and the inside of the landfill remains very dry using the sanitary landfill method. At present, municipal solid-waste landfills have a generalized landfill-gas recovery and energy conversion. However, delayed decomposition of waste due to drying of the landfill will prolong the post-management period and reduce the amount of landfill gas after final disposal, which has a serious impact on the economics. In this study, a leachate recirculation facility was installed at the SUDOKWON landfill site in Incheon to prevent drying of the inside of the landfill. We investigated the effects of leachate recirculation on landfill gas evolution by observing the changes in water content and landfill-gas collection. As a result, the amount of landfill gas collected after recycling the leachate for about 34 months showed an increase of about 71% compared to the control. Therefore, the increase of water content through leachate recirculation greatly influences landfill-gas production, and it can increase the return from the landfill-gas energy project.

핀란드 등의 유럽국가와 미국에서는 이미 오래전부터 매립지로 침출수를 재순환하고 있다. 이들 국가는 크게 두가지 목적으로 침출수를 재순환한다. 첫째, 소규모 매립지의 경우 별도의 침출수 처리시설이 없어 침출수처리 목적으로 매립지 내부로 침출수를 재순환하는 것이고, 두 번째는 건조한 지역의 매립지에서 수분공급을 통한 폐기물 분해활성화를 위해 재순환하는 것이다. 이러한 분해활성화는 매립가스 증산과 매립지 조기 안정화에 기여한다. 이들 국가의 재순환 방법은 단순히 살수차를 이용하여 매립현장에 침출수를 직접 살포하는 방식에서부터, 매립지 내 폐기물 층에 수평형 또는 수직형의 주입시설을 설치하여 매립지 내부로 주입하는 형태의 방식도 적용하고 있다. 국내의 경우, 최근까지 침출수를 매립지로 재순환할 수 있는 법적 근거가 없었으나, 2016년 4월에 그 근거가 마련되었다. 즉 매립지로 반입되는 폐기물의 성상이 하수슬러지 등 유기성 폐기물의 직매립 금지로 인해 매우 건조화 되었고, 또한 복토 기준 강화로 인해 매립지 내부로 우수의 유입도 크게 차단되어 매립지 내부가 많이 건조화 되었다는 것을 정부에서도 인식한 것이다. 본 연구에서는 수도권매립지 제2매립장내 2개블럭에 대하여 침출수 재순환을 통한 함수율 변화와 이에따른 매립가스 포집량 변화를 관찰하여 매립가스 증산에 어떠한 영향을 미치는지 파악하고자 하였다. 이에 3c, 4c 두 개 블록에 침출수 재순환시설을 설치하여 2013년 10월부터 2016년 12월까지 약 24만 m³의 침출수를 재순환하고 매립량 및 매립경과기간이 유사한 3d, 4d 블록과 함께 매립가스 포집량 등을 조사하였다. 그 결과 매립가스 포집량이 순메탄량 기준으로 대조구역 대비 1차년도 28.2%, 2차년도 36.7%, 3차년도에 60.6%의 증가율을 나타낸 것으로 조사되어 침출수 재순환이 매립가스 증산에 크게 영향을 미치며 이를 통해 매립가스 자원화사업에 큰 기여를 할 수 있을 것으로 판단되었다.

In this study, the experiment was carried out to produce methane by applying Semi-Continuous Leachate Recirculation Anaerobic Digestion System fed with source separated food waste from school cafeteria. There were two systems and each system consisted of a bioreactor and a leachate tank. Each bioreactor had a screen near the bottom of the reactor. 2L of Separated leachate was collected to the leachate tank each day by using a tubing pump and the leachate from the leachate tank was pumped to the bioreactor at the upper of the bioreactor. Through this circulation, the leachate having high concentration of VFAs was supplied to the bioreactor. At the beginning of the experiment, food waste/inoculum anaerobic sludge volume ratio was 2:8 that is 9g VS/L of OLR(Organic Loading Rate). Feeding was conducted every two weeks. Initial conditions of bioreactor was 30g VS/2･week and 33g VS/2･week were fed to bioreactor A and bioreactor B, respectively. Average biogas yields of the bioreactor were 0.723m³ Biogas/kg VS added in reactor A and 0.648m³ Biogas/kg VS added in reactor B.

The purpose of this study was to evaluate the applicability of the microbial fuel cell for the combined treatment of food waste water and landfill leachate. Contents of the study was to develop a carbon-containing electrode material radially to maximize microbial attachment. Also to evaluate the electric energy production efficiency by combining the electrode surface coating technology. By using a microbial fuel cell organic matter and nitrogen removal efficiency is evaluated for the food waste water and landfill leachate. BET to evaluate the surface characteristics of the developing electrode (Brunauer Emmett Teller) To evaluate the coating adhesion through measurement and to evaluate the adhesion characteristics micro-organism Weighing. Excellent electrical conductivity in the development electrode platinum, cobalt, by coating a catalyst such as palladium and to evaluate the electric energy generation efficiency. Lab. scale reactor capacity is a 5 L, and to configure the cross-section and the oxidizing electrode as cathode sequentially added.