Effectiveness of Shimizu PFAS Soil Remediation Technology confirmed in the U.S.

― high PFAS removal efficiency of 99% achieved by soil washing ―

  • Engineering
  • Environment

June 28, 2024

Through laboratory-scale testing in Texas, Shimizu Corporation (President: Kazuyuki Inoue) recently confirmed that its soil washing technology can remove 99% of per- and polyfluoroalkyl substances (PFAS) from contaminated soil in the U.S. The tests are being conducted in cooperation with U.S. engineering firm, Los Alamos Technical Associates, Inc. (LATA) and Amarillo College since June 2023. Test results have indicated the validity of Shimizu technology for PFAS-contaminated soil remediation, and a small-scale field test is now being planned to demonstrate the effectiveness of the technology.

PFAS are a large group of synthetic compounds that exhibit both hydrophobic and hydrophilic, surfactant-like properties. They have been used in a wide variety of products, such as coatings and fire extinguishing foam because of their heat resistance and ability to repel both water and oil. However, due to their resistance to natural degradation in the environment, concerns have been raised about their persistence and accumulation in the environment and living organisms. For these characteristics, PFAS have been dubbed “forever chemicals” and their regulations are being tightened worldwide.

The U.S. is one of the leading countries for the regulation of PFAS, i.e., PFOS/PFOA, two of most well-known PFAS compounds, have been designated as hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA, also known as the “Superfund” act), which is expected to lead emerging demand for PFAS-contaminated soil remediation.

Shimizu’s soil washing technology includes particle size separation by which contaminants are concentrated, as well as flotation – a process which enhances the quality of the cleaned soil through the attachment of contaminant-bearing particles separated from the soil, to the surface of air bubbles rising in water. Cleaned soil can then be reused for backfilling and other purposes. The greatest advantage of soil washing is that it reduces the amount of soil requiring further cleanup, such as incineration, resulting in lower overall treatment costs.

In anticipation of future demand, Shimizu has been developing PFAS-contaminated soil remediation technology since fiscal 2021, by adapting its proprietary technologies to the characteristics of PFAS. During laboratory-scale testing in the U.S., 99% PFAS removal from both contaminated soil and soil washing process water, has been successfully confirmed.

Moving forward, Shimizu is currently planning a small-scale field test to demonstrate the validity of its technology, followed by PFAS-contaminated soil remediation projects in the U.S, as well as Japan.

≪For Reference≫

Laboratory-scale testing of PFAS-contaminated soil washing technology in the U.S.

Laboratory-scale testing in progress
Laboratory-scale testing in progress
Flotation test
Flotation test
Laboratory-scale testing results
Laboratory-scale testing results

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