Elution control of radioactive cesium in MSWI fly ash using water repellent treatment

Abstract

Radioactive cesium found in municipal solid waste incineration (MSWI) fly ash can be easily eluted through contact with environmentally sourced water, such as rainwater. Dissolution suppression treatment of radioactive cesium, such as through cement solidification or geopolymer solidification, has been previously studied. Treatment through solidification requires the addition of a fixation agent, which results in an increase in the volume of fly ash following solidification. It is likely that the level of security at the landfill site will be high. In an attempt to simply suppress the elution of water-soluble radioactive cesium from MSWI fly ash without an increase in volume, we examined a water-repellent treatment method using four types of water repellents. Our results indicate that when the incinerated fly ash is impregnated and mixed with a commercially available water repellent, such as a silane-based oligomer, an alkyl alkoxysilane compound, or a fatty acid, it is possible to suppress the elution of radioactive cesium without a corresponding increase in fly ash volume.