How to Recover Soil from Mixed Wastes? Separability of Soil and Wastes

In disasters such as tsunamis and floods, a large proportion of disaster waste is a mixture of soil and other materials, which needs to be effectively separated for material recovery and utilization. In this study, pilot-scale and laboratory tests using rotary and vibrating screens were performed on soil–wood chips’ mixtures. In addition, soil modifiers—quicklime (CaO) and MgO-based material—were also used to improve the separability of the mixtures. In the pilot-scale and the laboratory tests, the percentage passing turned from decreasing to increasing around the plastic limit of soil. The rotary screens could result in better separation efficiency compared to the vibrating screen. The addition of 1% for quicklime and 5% for MgO by dry mass can be expected to improve the separation efficiency even under conditions that cause significant aggregation.