Abstract
Though various efforts have been performed toward establishment of a resource-cycle oriented society, the landfill site is still prerequisite as a basic infrastructure for waste management. However, construction of new landfill site is extremely difficult mainly due to the financial problem or NINPBY problem. Recently, a new method, which can reproduce landfill capacity at an existing landfill site, is paid to attention. In this method, landfilled waste is dug up from the landfill site in order to reproduce the new space. Then the waste is physically selected, and it is carried to the melting facility. The waste, which is dug up from the landfill, is finally melted into slag and utilized as construction materials. This method, however, might require additional energy use and cause larger CO2 emission compared with the case in which a new landfill is constructed.
From the global viewpoint, this study aims to estimate the green house gas emissions from the operation of above method. Results indicated that the melting process caused significant amount of CO2 emission due to the fuel consumption and pyrolysis gasification of the waste. On the other hand, methane gas, whose global warming effect is 21 times larger than CO2, is not generated from the landfill site so that digging up of landfilled waste and its melting prevents degradation of organic matters in the waste. Therefore, it was suggested that the method of reproducing landfill capacity is preferable to be applied to the anaerobic landfill site in which waste was directly landfilled without incineration.
