Detailed Summary of Groundwater Contamination Countermeasures in Koto Ward, Tokyo

Detailed Summary of Groundwater Contamination Countermeasures in Koto Ward, Tokyo

In 1999, in the Kameido and Sunamachi areas of Koto-ku, Tokyo, benzene concentrations in groundwater reached 2.0 mg/L, 200 times the environmental standard (0.01 mg/L), and trichloroethylene (TCE) was found to be seriously contaminated, exceeding 2.4 mg/L, 80 times the standard (0.03 mg/L). In response to this, the Ministry of the Environment (MOE) announced the use of microorganisms. In response, the Ministry of the Environment established guidelines for the introduction of bioremediation, a purification technology using microorganisms, and several companies cooperated to promote the cleanup, with Nittobo providing oxygen supply equipment and Kaneka supplying degradation accelerators. By injecting oxygen and nutrients (0.5 kg of phosphoric acid and 0.2 kg of nitric acid) into the soil, the project has proven effective in reducing benzene concentrations by 90% in one month and TCE concentrations by 85% in three months, The new technology is also effective in other areas of To
kyo.