Development of pilot-scale electrokinetic remediation technology to remove 60Co and 137Cs from soil

Pilot-scale electrokinetic remediation equipment suitable to the geological characteristics of South Korean nuclear facility sites was developed for the remediation of radioactive soil. The optimal experiment conditions were chosen through pilot-scale electrokinetic remediation experiments, and the experimental results are presented. The removal efficiencies of Co2+ and Cs+ from artificially contaminated soil after 15 days were 98.4 and 94.9, respectively, and the generated effluent volume was 3.4 ml/g. The removal efficiencies of 60Co and 137Cs by nitric acid were increased by 3.1% and 2.0% more than those by acetic acid. Moreover, when nitric acid instead of acetic acid was used, it had an advantage of a reducing electricity consumption due to its higher electrolytic conductivity. The higher the radioactivity concentration of the soil was, the more the removal efficiencies of 60Co and 137Cs were increased. Namely, the removal efficiencies of 60Co and 137Cs from the soil of high concentrations were increased by 14.4% and 3.8% more than those from the soil of low concentrations. The larger the particle size of the soil was, the more the removal efficiency of 137Cs increased. Namely, the removal efficiency of 137Cs from the soil of an average 1.4 mm particle size was increased by about 2.3% more than that from the soil of an average 0.7 mm particle size. Also, the removal efficiencies of 60Co and 137Cs by the application of an electric current of 15 mA/cm2 were increased by 1.4% and 4.4% more than those by the application of 10 mA/cm2. Therefore, the total removal efficiency of 60Co and 137Cs from the radioactive soil of about 2000 Bq/kg was 95.8% by an electrokinetic remediation by the application of an electric current of 15 mA/cm2 for 55 days.