Soil Mixing for Remediation of Contaminated Sites

Abstract

Soil mixing involves mixing an additive into soil to change the physical or chemical properties of a soil. This geotechnical method is called solidification/stabilization (S/S) treatment when applied for remediation of contaminated soil or sediment. S/S is an established technology for contaminated site remediation. The effectiveness of S/S treatment for a broad variety of soil contaminants is demonstrated by the technology’s high selection rate for remedies at U.S. Superfund sites. According to U.S. Environmental Protection Agency’s 2017 report on Superfund remedies, S/S has been selected for 21% of in situ treatment source control remedies. Most Superfund projects involve contaminated soil. S/S is of increasing interest in in-place or in situ treatment of contaminated soil such as those found at former industrial properties. In situ S/S can prepare “brownfield” sites for redevelopment. S/S treatment protects human health and the environment by immobilizing hazardous constituents within the treated material. Successful treatment is accomplished through physical changes to the soil and often, chemical changes to the hazardous constituents themselves. S/S binding agents are mixed into contaminated soil through a variety of construction techniques including shallow and deep soil mixing. An appreciation of the versatility for the treatment technology can be gained by review of example projects. This paper discusses the principles and application of S/S treatment technology for soil and sediment.