Evaluation and optimization of biogasification technology for kitchen waste to promote sound material-cycle society

1. 我们对日本和欧洲的厨余垃圾和牲畜排泄物的生物气化设施进行了调查。开发了能够定量评价生物气化对减轻环境负担和抑制自然资源消耗效果的评价项目。在北海道的三个餐厨垃圾生物气化设施中，我们连续监测了沼气的体积、沼气中甲烷和二氧化碳的浓度、设施的气味、废液和处理水中的BOD、COD、SS、总氮浓度和大肠菌群数量，这些都是生物气化评价项目的组成部分。沼气中的甲烷浓度根据设备的不同而不同，大约在55%到60%之间。一吨厨房垃圾产生的甲烷量约为80至100立方米。由于采用了不同的除臭设备和污水处理设备，恶臭和水污染物的排放水平有所不同。然而，每吨厨房垃圾产生的沼气量以及沼气中甲烷和二氧化碳的浓度，在不同的年代并没有太大的变化。3个设施对废液进行了适当的处理，处理后的废水基本达到国家排放水标准。厨房垃圾产生的甲烷量因垃圾质量的不同而有很大差异。因此，为了提高餐厨垃圾的生物气化效率，居民的合作是必不可少的。我们开发了分离甲烷和二氧化碳的聚合物膜的材料和制造方法。因此，我们获得了实际应用甲烷浓缩装置的一些基本信息，该装置采用膜来根据预期的最终用途控制沼气中的甲烷水平到最佳水平。少

1. We have investigated biogasification facilities for kitchen garbage and livestock excreta in Japan and Europe. The biogasification evaluation items which can evaluates quantitatively the effect of biogasification for reduction of the environmental burden and the restraint of the natural resource consumption were developed.2. At three biogasification facilities for kitchen garbage in Hokkaido, we have continuously monitored the volume of biogas, concentrations of methane and carbon dioxide in the biogas, the odor from the facilities, concentrations of BOD, COD, SS, total nitrogen, and coliform bacteria count in liquid residuum and treated water, all of which is the component of the biogasification evaluation item. The methane concentration in the biogas, which varied according to the facilities, was about from 55 to 60 %. The amount of methane generated from one ton of kitchen garbage was about from 80 to 100 m^3. There were the differences in the level of odor and water pollutants e … More mitted from the facilities as various deodorizing and wastewater-treatment equipments were adopted. However, the amount of biogas from 1 ton of kitchen garbage and concentrations of methane and carbon dioxide in biogas, at each facility did not vary much across the ages. Liquid residuum was properly processed at all of the three facilities, thus their treated waste water amply fulfilled the national standard of discharge water.3. The amount of methane generated from kitchen garbage varied vastly by the quality of garbage. Thus we concluded that the cooperation from the residents to separately discharge the kitchen waste is indispensable in order to improve the efficiency of biogasification.4. We have developed the materials and manufacturing method of the polymer membrane that can separate methane and carbon dioxide. Therefore, we have obtained some fundamental information to practically apply the methane concentrating device that applies the membrane to control the methane level in the biogas to an optimal magnitude according to the intended end-usages. Less