The municipal solid waste incineration ash from the Fukushima Prefecture includes radioactive Cs. There is a need to grasp the basic physical properties of this ash, determine the leaching properties of radioactive Cs, and examine leaching suppression methods in order to continue to advance appropriate disposal techniques. For this purpose, we carried out material sampling from a municipal solid waste incineration plants in the Fukushima Prefecture in summer and winter. We then conducted tests on the samples. Results showed that the radioactive Cs leaching suppression method for mixing clay minerals at weight ratio of 5 to 20％ can become an effective safety measure.
To develop a new wastewater treatment system using soil, artificial soil aggregates were produced using a stirring granulation method. The water purification performance of artificial soil aggregates was evaluated under high-speed treatment conditions. Artificial soil aggregates contained high levels of organic matter and phosphorus removal capacities compared to earthworm cast aggregates and silica sand. However, the purification performance of sawdust mixed artificial soil aggregates was relatively low, which was likely due to the formation of a thick biofilm. The purification performance of iron powder mixed artificial soil aggregates decreased when excessively aerated, which was likely due to the production of excessive iron oxides around them. Zeolite mixed artificial soil aggregates had higher levels of ammonia and nitrogen removal capacities. Although artificial soil aggregates displayed the same nitrogen removal rate as conventional soil-based systems, further studies are needed to improve its nitrogen removal capacity.