### The History and Current Status of Oil-Contaminated Soil Remediation in Sano City, Tochigi Prefecture

### The History and Current Status of Oil-Contaminated Soil Remediation in Sano City, Tochigi Prefecture

**2000s: Establishment and Foundation Building**
In Sano City, Tochigi Prefecture, the joint venture "Solec Tochigi," established by Kashima Road, Nissan Chemical Corporation, and Otosaka Crushed Stone Mining, began its oil-contaminated soil remediation operations. The facility adopted the "Drum Soil Method®," which uses low-temperature heating technology at 200–300°C to efficiently volatilize oil components in the soil. The processing capacity reaches 10–30 tons per hour. The remediated soil is reused as landfill material at quarry sites, contributing to local resource circulation. This technology won the Civil Engineering Society's Environmental Award in 2008 and gained nationwide attention.

**2010s: Expansion of Remediation Demand and Technological Advances**
During the 2010s, the revision of the Soil Contamination Countermeasures Law and strengthened municipal regulations led to active investigations of oil contamination at factory and gas station sites. "Solec Tochigi" saw an increase in contaminated soil intake both domestically and internationally, significantly increasing processing cases. On-site treatment and desalination technology were also advanced, improving efficiency and reducing costs. Major companies such as Kashima Construction began pilot-testing new technologies, advancing industry-wide innovation. These initiatives enhanced the facility's reputation and earned international recognition.

**2020s: Transition to Sustainable Technology**
In the 2020s, efforts to further reduce environmental burdens have progressed, with research advancing in phytoremediation (a technique utilizing plants for remediation) and iron powder-based desalination methods. "Solec Tochigi" has improved traditional methods and adopted new remediation techniques, strengthening its capability to handle large-scale soil contamination. Additionally, a resource circulation model was established, enabling the reuse of remediated soil within the region, expanding contributions to the local community. The facility is recognized as a model initiative for environmental conservation and sustainable development.

**Summary**
"Solec Tochigi" in Sano City, Tochigi Prefecture, has pursued technological innovation and environmental conservation through its oil-contaminated soil remediation projects since the 2000s. Today, it plays a critical role in advancing environmental technology and resource circulation, gaining attention both domestically and internationally. Further development is anticipated through the adoption of new technologies and deeper collaboration with the community.