Abstract
Life cycle CO2 evaluation of kitchen garbage treatment in a house using Johkasou was conducted to compare the impacts of two scenarios. First one is a present case in which kitchen garbage is incinerated with other domestic waste and treats domestic wastewater in Johkasou, and second case is a simultaneous treatment of domestic wastewater and kitchen garbage in household Johkasou. In the second case, disposer was used for kitchen garbage and newly developed Johkasou for this case was used. Potential contributions of these two cases to CO2 emission in the processes of waste treatment and domestic wastewater treatment were assessed by LCA. A case of a simultaneous treatment of kitchen garbage and domestic wastewater decreased in transportation amount of domestic waste and net CO2 emission was reduced by 7.8％ (39.9 kg－CO2 house－1 year－1). Because transportation of domestic waste influences CO2 emission to a greater degree than in Johkasou sludge transportation, a simultaneous treatment process of kitchen garbage and domestic wastewater can reduce more LCCO2 when the transportation distance of domestic waste is long.
