Purifying the Land of Kawasaki - A Story of Urban Renewal and Soil Purification (2007)

Purifying the Land of Kawasaki - A Story of Urban Renewal and Soil Purification (2007)

In the 2000s, soil contamination remaining on former factory sites and reclaimed land emerged as a serious issue in Japan's urban redevelopment efforts. 2003 saw the enforcement of the Soil Contamination Countermeasures Law, which made surveys and remediation measures mandatory, and demand for remediation technologies and facilities increased nationwide. Shimizu Corporation obtained a permit in Kawasaki City in 2005 and installed a large-scale facility capable of processing 960 tons per day. The facility is capable of both on-site and off-site treatment, and can flexibly accommodate large-scale redevelopment projects as well as small-scale construction.

The facility features a combination of various technologies depending on the contaminant. Soil washing and solidification/stabilization are used for heavy metals, while low-temperature thermal desorption at 150-350°C is used for oil contamination, and catalytic oxidation and activated carbon are used to remove volatilized components. Soil gas suction (SVE), air sparging, and permeable reaction walls are utilized for chlorinated organic compounds, and pump-and-treat is used for groundwater contamination. Chemical oxidation (ISCO) is applied for persistent organic matter, allowing optimization according to site conditions.

Emphasis was also placed on sub-processing, with coagulation sedimentation and filtration/activated carbon used to treat cleaning wastewater within standards, and a filter press used in the dewatering process to reduce water content. Consideration was also given to risk communication, including dust and odor countermeasures, logistics management, and resident explanation. Furthermore, quality was ensured through preliminary investigations using CPT and MIP, rapid analysis using PID and GC-MS, and transparency through third-party verification.

The Kawasaki facility was not only an environmental measure, but also an advanced example of linking urban renewal and environmental business. By treating contaminated soil and promoting redevelopment, the project embodied the trend "from brownfield to greenfield," and was a symbolic effort to integrate the environment and the economy.