Development and Current Status of Bioremediation Technology (1999 - 2020s)

Development and Current Status of Bioremediation Technology (1999 - 2020s)

In April 1999, the Ministry of the Environment formulated guidelines for "bioremediation" aimed at groundwater pollution purification. These guidelines recommend technology that utilizes the functions of microorganisms to decompose volatile organic compounds (VOCs) in groundwater, especially harmful substances such as benzene, trichloroethylene (TCE), and carbon tetrachloride. Key target areas included the former industrial areas of Koto Ward, Tokyo, and Takasago, Osaka, where benzene concentrations in groundwater were found to reach 200 times Japan's environmental standards (0.01 mg/L). Therefore, the guideline recommended methods to inject oxygen and nutrients (phosphoric acid, nitrate, and calcium) into the soil to enhance the degradation process by indigenous microorganisms.

In the implementation of this technology, Nitto Boseki provided oxygen supply equipment, and Kaneka, with its microbial culture technology, was involved in the development of decomposition-promoting agents. For example, injecting 0.5 kg of phosphoric acid and 0.2 kg of nitrate into 1 cubic meter of contaminated soil was expected to reduce benzene concentration by up to 90% within a month. Regarding trichloroethylene, a three-month treatment achieved an 85% reduction in the initial concentration. Additionally, future plans included the consideration of using genetically modified microorganisms, with discussions centered on the feasibility of practical application under safety and ethical considerations.

In the 2020s, bioremediation technology has steadily advanced, and new methods have been developed. The National Institute of Technology and Evaluation (NITE) and Taisei Corporation jointly developed a groundwater purification technology using the Dehalococcoides strain UCH007, successfully reducing the purification period by about two months and cutting costs by about 50%. In a specific application example, in an industrial area in Tokyo, the technology reduced trichloroethylene concentration, which was more than 10 times the standard value (0.03 mg/L), to below the standard value in a short period.

Furthermore, research from the National Institute for Environmental Studies reports that bioremediation can be applied to a wide range of pollutants, including petroleum hydrocarbons like benzene and toluene, as well as dioxins and chlorine-based pesticides. The Ministry of the Environment and the Ministry of Economy, Trade and Industry have also formulated "Guidelines for the Use of Bioremediation by Microorganisms" to ensure safe use, promoting appropriate management methods to minimize environmental impact.

In this way, bioremediation technology aims to reduce environmental burdens and improve cost efficiency, with technological innovation and widespread adoption expected to continue in the future.