Demonstration of Drying Sewage Sludge Containing Radioactive Materials for Storage and Transport

Due to the accident at Tokyo Electric Power Company’s Fukushima Daiichi Nuclear Power Plant, radioactive materials were detected in sewage sludge, and Horikawa-Cho Sewage Treatment Plant, which is located in Fukushima city, had been forced to store sewage sludge within the site. The Ministry of the Environment was implementing a project to reduce the storage space volume of the stored sludge and to stabilize the sludge properties by drying sewage sludge, so that it can be easily transported outside of the site. These drying facilities operated from April 2013 to October 2014. The total volume was about 7,726 tons and the weight was reduced to one-fifth. The average radioactive concentration of the dried sludge is 44,000 Bq/kg (=44 Bq/g) and the maximum is 252,000 Bq/kg (=252 Bq/g). Now, the dried sewage sludge is stored in the Aeration Tanks, which are not currently in use for the sewage treatment system. And transport to the incinerating facility is continuing.