Press Releases

Kurita Water Industries Ltd. (Head Office: Nakano-ku, Tokyo; President: Michiya Kadota; hereinafter "Kurita") is pleased to announce that it has developed and started applying the Power Bio E-PLUS^™, a new technology of purifying soil contaminated with volatile organic compounds (VOCs), part of the contaminants in soil and groundwater, without soil excavation.

The Power Bio E-PLUS^™ is a new technology that microbially decomposes and detoxifies VOCs attached on soil after heating them so that they will be dissolved into groundwater. Since it requires no soil excavation for reaching the source of contamination, it allows the purification process to be started even when the factory is in operation. In addition to that, it controls the rebound, which was a drawback with the conventional in-situ purification technology, to clear soil and groundwater pollution in a short time and without fail.

At a location where a factory stands, hazardous chemical substances that were used in the past and wastewater may penetrate the ground from the surface and remain in the soil. Business operators may have to remove these pollutants at the time of extending or renovating the factory building or selling the site. If soil or groundwater underneath the building is polluted, it is difficult to dismantle the building while it is in operation. Instead of removing contaminated soil through excavation, in-situ purification is conducted, such as bioremediation, in which microorganisms are injected into the groundwater to decompose contaminants. Classified as contaminants, VOCs easily permeate the soil and reach deep within the ground. If they reach a low-permeability layer, they are absorbed into the soil and cannot be completely removed by bioremediation. A rebound then occurs, in which VOCs gradually elute into the groundwater. That prolongs the purification period.

Recently developed by Kurita, the Power Bio E-PLUS^™ is a new soil and groundwater remediation technology that combines the electrical resistance heating method^*1 with the KuriAUG bio-powered^® method^*2. The first method features an electric current between electrodes placed in the ground, which heats the soil to elute VOCs absorbed in the soil in the low-permeability layer into groundwater. The second method employs a microbial effect to decompose and detoxify the VOCs dissolved in groundwater.

This technology removes VOCs from soil in the low-permeability layer and controls the rebound after remediation. Consequently, it fulfills the requirements for completion of removal under the Soil Contamination Countermeasures Act. This specifically refers to the maintenance of conformity to the standards for groundwater for two years after purification. In addition, heating of the soil has the effect of stimulating microbial activities. The new technology requires a much shorter purification period compared to the conventional bioremediation technology.

This technology requires no soil excavation for remediation. It means that it is applicable to contamination under the factory building in operation. It also requires no excavation, conveyance or disposal of contaminated soil with heavy machinery. It emits less CO₂ than excavation and remediation.

Going forward, Kurita will combine the Power Bio E-PLUS™ with its own direct sensing technology for identifying the source of contamination and with a simulation technology for predicting the purification period to identify the source of contamination more accurately for optimizing the remediation. It will thus offer reliable soil and groundwater remediation for factories in operation to help further reduce the impact on the environment.

The Kurita Group will offer its original technologies, products and solutions to resolve water and environmental issues and thereby to realize a sustainable society.

• *1A technology of applying electric current between electrodes placed in the ground to heat the soil to a temperature range of 40°C to 80°C and to dissolve in groundwater VOCs absorbed in soil particles. Kurita acquired a license for the electrical resistance heating method and purification equipment from Shimadzu Corporation in May 2021.
• *2 Kurita's original technology of injecting pre-cultured bacteria and nutrients into the ground to decompose and detoxify VOCs. It is applicable to sites where no bacteria that decompose contaminants exist in the ground. It has a shorter purification period than the method of injecting nutrients only.
  For details about this technology, please refer to the related press release below.
  ■ Achieving mass cultivation of degrading microbes that allow for large-scale decontamination of soil and groundwater
  —Enhancing KuriAUG bio-powered methods of purification technology for soil and groundwater, detoxifying even vinyl chloride monomer—

Schematic of application of the Power Bio E-PLUS^™