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

1.我们考察了日本和欧洲的厨房垃圾和牲畜排泄物的生物气化设施。建立了能够定量评价沼气对降低环境负担和抑制自然资源消耗的效果的沼气评价指标。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量、沼气中甲烷和二氧化碳的浓度、设施发出的气味、液体残渣和处理后水中的BOD、COD、SS、总氮和大肠菌群的浓度，这些都是沼化评价项目的组成部分。沼气中的甲烷浓度因设施而异，约为55%至60%。每吨厨房垃圾产生的甲烷量约为80至100m^3。气味和水污染物的水平存在差异e…随着各种除臭和废水处理设备的采用，更多的设施被释放出来。然而，在每个设施中，1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年代之间没有太大差异。三个设施的液体残渣都得到了适当的处理，处理后的废水完全达到了国家排放水的标准。厨房垃圾产生的沼气量因垃圾质量的不同而有很大差异。因此，为了提高沼气利用效率，居民的配合对餐厨垃圾的分类排放是必不可少的。我们开发了能够分离甲烷和二氧化碳的聚合物膜的材料和制造方法。因此，我们为甲烷浓缩装置的实际应用提供了一些基础信息，该装置利用膜将沼气中的甲烷水平控制在根据预期的最终用途的最佳幅度。较少

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