輸送手段を考慮した都道府県間廃棄物移動モデルによるエネルギー消費量とCO<sub>2</sub>排出量の推計

Abstract

Objective. The waste transportation between regions causes various problems such as the transfer or increase of environmental loads. For example, the amount of waste to treat increases in the receiving regions and the energy consumptions and CO2 emissions which are accompanied with the waste transportation increases. The main transportation means of waste is by truck, however, countries or areas which are surrounded by bodies of water such as Japan, waste transportation by ship occupies the great importance. In this study, we shall try to construct a waste transportation model with more practical and detailed assumptions than the preceding study (Kagawa, Kondo 2007) by assuming the multiple means of transportation. In this model, we shall consider the energy consumptions and the environmental loads that are necessarily accompanied with the waste transportation between regions.Results and Discussion. Based on the related statistical data, we construct an interregional waste transportation model, especially for industrial waste for the intermediate treatment which occupied about 90% of the total amount of waste. First, we compile the amount of interregional waste transportation from a departure to a destination for every combination of prefectures in Japan; which is expressed as a matrix whose row sectors are waste types and column sectors are transportation means. Next, we estimate the distance matrices between prefectures for each transportation means. Then, by multiplying the amount of transported waste by the transportation distance, the amount of transported waste based on freight ton-kilometers is calculated. Finally, from these values we can estimate specific energy consumptions and CO2 emissions originated from waste transportation. The estimation results show us that generally the waste is transported among neighborhood prefectures. The construction wastes and the waste plastics are typical examples and about 75% of these types of waste are moved by truck. On the contrary, such wastes as dust and cinders are transported by ship for great distance. In freight ton-kilometers basis, the Chubu block exports large amount of waste to other blocks. On the contrary, the Kyushu block imports large amount of waste from other blocks. Exports from the Kanto, Chubu and Kinki blocks to the Chugoku block are also large. The Hokkaido and Kanto block also import wastes from the Hokkaido, Kanto, and Chubu blocks. Dust is exported from all blocks to the Shikoku and Kyushu blocks. With respect to the means of transportation the exports by ship to the Kyushu block are significantly large. We find that about 92% of energy consumptions and CO2 emissions are attributed to the transportation by truck, although the freight based on ton-kilometer by truck and by ship are about 56% and 44%, respectively.Conclusions. In this study, we constructed an interregional waste transportation model by assuming the multiple means of transportation. The results of estimation show that energy consumptions and CO2 emissions accompanied with interregional waste transportation are, largely, depend on truck transportation. It is clearthat the change of the transportation system is fundamentally important for the reduction of environmental loads. Our next objective will be the estimation of the impact of the transportation of the industrial waste for landfilling. Consideration of other environment loads such as NOX, SOX and SPM, and the scenario analysis for various choices of waste transportation system are also important. We will also try to apply this model to the interregional waste input-output analysis.