使用済み紙おむつのマテリアルリサイクルのライフサイクルインベントリ分析

抄録

Background and Objective. As Japan’s population has aged, the amount of disposable diapers discarded has steadily increased. At present, disposable diapers from households are incinerated as general waste and disposable diapers from care facilities and hospitals are incinerated as business or industrial waste. Current recycling methods for disposable diapers include thermal recycling and material recycling. However there are many problems with recycling process such as sanitary issues of diapers caused by the attached waste and problems on separating them. As a result, recycling of disposable diapers is primarily conducted at waste-power generation plants and not at other garbage processing plants. Technology to extract recycled pulp from used disposable diapers is currently being developed with the goal of creating a recycling system that would allow disposable diapers to be produced from recycled disposable diapers. In this study, we carried out a life cycle assessment (LCA) for a water-based recycling system and existing incineration disposal methods for disposable diapers.
Evaluation Objective and Analysis Method. The reduction of environmental load was evaluated by calculating carbon dioxide emissions with an LCA method. The evaluation begun after disposable diapers being transported to the recycling plant, and ended when they were broken down into different materials and were ready for secondary reuse. The comparison target is incineration and landfill disposal on the assumption that this is the traditional treatment for used disposable diapers. The functional unit is the annual amount of used disposable diapers delivered to the recycling plant.
Conclusions. Carbon dioxide emissions were lower in the water-based recycling system as compared with disposal by incineration. For this type of recycling business to be sustainable, however, payability is the most significant problem. From a standpoint of continuity and development of recycling, it will be very important to construct a stable collection system of used disposable diapers. A subject for future study is to quantitatively show the effect of expanding the recycling area.