A simple system that combines washing and sieving contaminated soil to remove radioactive cesium, which could be utilized near the crippled Fukushima No. 1 nuclear power plant, has been developed by a Kyoto University team.
A simple system that combines washing and sieving contaminated soil to remove radioactive cesium, which could be utilized near the crippled Fukushima No. 1 nuclear power plant, has been developed by a Kyoto University team.
The team, led by associate professor Haruhiko Toyohara, said the system should be of great use especially when decontaminating soil containing little clay, such as the topsoil in a house's garden and parks.
The new system will be presented at the September meeting of the Japanese Society of Fisheries Science in Nagasaki, Nagasaki Prefecture.
Toyohara experimented with the system using the soil from a park in Koriyama, Fukushima Prefecture, about 60 kilometers west of the Fukushima No. 1 plant. The soil contains 3,000 to 5,000 becquerels of radioactive cesium per kilogram, with the weight of fine clay in the soil comprising only 4 percent of the total.
When washing the soil through a sieve using a scrubbing brush, about 88 percent of cesium in the soil was transferred to the water. All cesium in the water was then gathered on the bottom of a container using a chemical agent. When sieving the washed soil to remove fine clay, about 99 percent of the cesium initially contained in the soil was eliminated.
The weight of contaminated soil removed through the process--the amount of the soil on the bottom and clay separated by sieving--was reduced to only 5 percent of the total of the original soil.