In Situ Soil Remediation

Treatment technologies and design solutions for contaminated soil

Soil remediation requires selecting treatment technologies that match the contaminant type, soil characteristics, and site conditions. In situ soil remediation treats contamination directly in place—eliminating the need for excavation, reducing costs, and minimizing disruption to site operations.

Hepure supports environmental consultants with both specialized remediation products and technical design guidance to develop effective soil treatment strategies across a wide range of contaminants.

Featured Visual: Representative visual for in situ soil treatment planning and field application.

Core Soil Remediation Technologies

In Situ Chemical Oxidation (ISCO) for Soil

Chemical oxidation is one of the most effective approaches for treating contaminated soil, particularly in source areas.

• Common oxidants: potassium permanganate, sodium permanganate, activated persulfate, and hydrogen peroxide.
• How it works: strong redox reactions degrade organic contaminants into less harmful compounds.
• Target contaminants: chlorinated solvents (TCE, PCE, DCE), petroleum hydrocarbons, PAHs, phenols, and certain pesticides.
• Why it works well in soil: solid forms can be blended directly into soil matrices, reactions are fast on contact, and treatment performs well in heterogeneous subsurface conditions.
• Typical applications: soil blending, in situ injection (low or high pressure), direct application in excavation zones, and source-area treatment.

Zero Valent Iron (ZVI) for Soil Remediation

ZVI provides abiotic chemical reduction, breaking down contaminants without relying on biological processes.

• How it works: ZVI donates electrons to contaminants, driving dechlorination of solvents, reduction of metals, and stabilization of polyatomic anions such as nitrate and sulfate.
• Target contaminants: chlorinated solvents (CVOCs), certain metals, nitrate, and sulfate.
• Key advantages: no dependence on microbial activity, minimal formation of harmful byproducts, and long-term subsurface reactivity.
• Application methods: soil mixing, blending, and in situ injection for high-concentration source zones.
• Product focus: Ferox Flow for distribution and longevity, and Ferox Target for fast-reacting applications.

Enhanced Bioremediation in Soil

Bioremediation leverages naturally occurring microorganisms to degrade contaminants.

• Aerobic bioremediation: calcium peroxide releases oxygen and supports treatment of petroleum hydrocarbons.
• Anaerobic bioremediation: electron donors such as emulsified vegetable oil (EVO) and sodium lactate promote reductive dechlorination of chlorinated solvents.
• Key advantages: cost-effective, sustainable, suitable for large treatment areas, and often effective as a polishing step after primary treatment.

Selecting the Right Soil Remediation Approach

Site Factors That Drive Technology Selection

Broadly, soil remediation strategies fall into two families: clean-up technologies, which destroy or remove contaminants, and stabilization technologies (also called containment), which lower a pollutant’s mobility and bioavailability. Both can be performed in situ or ex situ using physical, chemical, or biological processes — and Hepure supplies chemistries for both paths. Choosing correctly comes down to five site factors, typically documented in a detailed site assessment:

The soil matrix. Soil type (the percentages of sand, silt, and clay), fractured rock or sediment, and the degree of heterogeneity determine how amendments can be delivered and how they will distribute.

The contaminant profile. General categories include chlorinated volatile organic compounds (CVOCs), petroleum hydrocarbons, metals, inorganics, pesticides, PAHs, and PFAS. Some categories can be addressed with a single technology — CVOCs and metals, for example — while others require combined approaches. See our contaminants treated guide for chemistry-by-contaminant matching.

Concentration and mass. Many remedial methods perform best at lower concentrations; others are designed for elevated concentrations or free product. Source areas and dilute fringes rarely want the same treatment.

Remedial goals. Reaching TCLP standards requires a vastly different approach than removal for site closure. Define the finish line before selecting the route.

Matrix geochemistry. The most overlooked parameter: major cations and anions, mineral content, pH, buffering capacity, ion exchange capacity, salinity, and ORP. These interactions can be complex — arsenic stabilization, for instance, depends on the right pH and Eh conditions plus adequate iron and sulfate, which shift with bacterial activity. Geochemistry frequently decides whether a textbook technology works at your site.

Selection framework adapted in part from Lombi, E., & Hamon, R. E. (2005), Remediation of Polluted Soils, Encyclopedia of Soils in the Environment, Elsevier.

Integrated Soil Treatment Strategies

Many sites benefit from combining technologies:

• ISCO for rapid contaminant reduction
• ZVI for sustained treatment of residual contamination
• Bioremediation for long-term polishing

This integrated approach improves both short-term performance and long-term site closure outcomes.

Hepure Soil Remediation Solutions