A Green Technique for Cleaning Contaminated Soil TOWA CONSTRUCTION Co.,Ltd. IP

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TOWA CONSTRUCTION has developed an eco-friendly, plant-based method that renders a poisonous chemical compound harmless

Hexavalent chromium is a poisonous and carcinogenic compound that was a significant problem in Japan a generation back. Thanks to a solution from Hokkaido-based TOWA CONSTRUCTION Co., Ltd., other nations with developing industrial sectors can avoid the pollution caused by this chemical in an environmentally friendly way.

President Kotaro Arase of TOWA CONSTRUCTION watched the local building market grow smaller and realized that he needed to diversify into new business. Arase had learned about a novel plant-derived substance that had potential for removing contaminants from soil and wondered if there was some way he could use it for the March 2011 disaster–afflicted Fukushima Prefecture.

TOWA CONSTRUCTION’s Director, Masaaki Muroyama, who spent nearly two years in Fukushima on radiation-related research and development with the newly established Environmental Division of TOWA CONSTRUCTION, explains that “unfortunately, the substance had no effect on radiation, but after subsequent research and development back in Hokkaido, I discovered that it did affect hexavalent chromium.” Hexavalent chromium ( Cr(VI) ) is a poisonous and carcinogenic compound that was a significant problem in Japan about 40 years ago, when it contaminated soil in former factories and other industrial sites.

TOWA CONSTRUCTION Co., Ltd.’s Cr(VI) detecting agent is stable and can remain in the soil for long periods of time

The product can be added to any material that has been contaminated with Cr(VI)

Natural Chemistry

After mixing the substance with Cr(VI), the subsequent chemical reaction not only changed the compound to harmless trivalent chromium, it did so quickly and efficiently as well. Muroyama enlisted the help of expert Takayuki Asano to become the company’s Environmental Technology Advisor, and together the two set out to identify the specific chemical reaction involved.

Although Towa cannot divulge much about the origin of the substance or its chemical mechanism as they have not yet filed for patent protection, they see great potential in its quick ability to convert Cr(VI) and the fact that it is a plant-based compound. “Since it is natural it has less of an impact on the environment compared to competing chemical products,” says Asano. Towa’s product is also stable and does not oxidize, meaning it can stay in the soil and prevent the recurrence of Cr(VI).

Cleaning Up Industrial Sites Overseas

According to Asano, soil pollution involving Cr(VI) has largely been dealt with in Japan now. Consequently, Towa is focusing its attention on neighboring China, where contaminated land from past factories still remains untreated. They expect the Chinese government to pass regulation that limits contaminants in the soil, prompting efforts to clean up and restore soil conditions. After a number of laboratory experiments in Japan, TOWA CONSTRUCTION plans to conduct its first field test of the substance on a patch of land in the Chinese city of Shenyang later this year.

The company has been working quickly to reach out to this new market. Having developed the product in October 2014, they started exhibiting soon after at environmental-related trade shows in China in 2015, in hopes of partnering with local trading companies. TOWA CONSTRUCTION is also collaborating with other Hokkaido companies to provide package solutions for environmental products overseas. Muroyama adds that while China is their foremost market, they are considering other nations with large industrial areas such as Vietnam. “We're open to meeting demand wherever it is needed,” he says.

Based on interview in February 2016

TOWA CONSTRUCTION Co., Ltd.’s Masaaki Muroyama, Director (left) and Takayuki Asano, Environmental Technology Advisor (right)