In Situ Groundwater Remediation

Technologies, design, and treatment solutions for groundwater cleanup

In situ groundwater remediation treats contaminated groundwater directly within the aquifer—without pumping it to the surface. Reagents are delivered into the subsurface to destroy, transform, or immobilize contaminants in place.

Compared with traditional pump-and-treat systems, in situ methods are typically less costly, faster to implement, better suited for long-term plume management, and less disruptive to site operations. Those advantages have made in situ remediation the preferred approach for many groundwater cleanup projects across the United States.

Featured Visual: Representative visual for selecting and implementing in situ groundwater treatment technologies.

Core In Situ Remediation Technologies

In Situ Chemical Oxidation (ISCO)

ISCO uses injected oxidants to chemically destroy organic contaminants in groundwater.

• Common oxidants: potassium permanganate, sodium permanganate, activated persulfate, and hydrogen peroxide.
• Best applications: chlorinated solvents (TCE, PCE, DCE), petroleum hydrocarbons, and source-zone treatment requiring rapid mass reduction.
• Key advantages: rapid contaminant destruction, effectiveness in high-concentration zones, and flexible injection approaches.
• Permanganate note: permanganate-based ISCO is especially effective for chlorinated solvents and can remain active for weeks to months.

In Situ Chemical Reduction (ISCR)

ISCR uses reducing agents to transform contaminants into less harmful compounds.

• Primary technology: zero valent iron (ZVI).
• How it works: ZVI promotes abiotic reductive reactions, breaking down chlorinated solvents and reducing metals.
• Applications: CVOCs, soluble metals including hexavalent chromium, and polyatomic anions such as nitrate and sulfate.
• Deployment methods: direct injection into contaminated zones or installation as permeable reactive barriers (PRBs).
• Performance: passive, long-term treatment ranging from 3 to 15+ years.
• Additional ISCR reagent: calcium polysulfide for metals stabilization, especially chromium.

Enhanced Bioremediation

Bioremediation enhances naturally occurring microbial processes to degrade contaminants.

• Anaerobic bioremediation: targets chlorinated solvents and uses electron donors such as emulsified vegetable oil (EVO) and sodium lactate.
• Aerobic bioremediation: targets petroleum hydrocarbons and uses oxygen-release compounds such as calcium peroxide.
• Key advantages: cost-effective, sustainable, and well-suited for polishing or long-term treatment prior to monitored natural attenuation.

Adsorption-Based Treatment (PFAS & Recalcitrant Compounds)

Some contaminants—especially PFAS—do not readily degrade chemically or biologically. Activated carbon forms a subsurface adsorption zone that captures contaminants as groundwater flows through.

• Solutions: colloidal activated carbon (CAC) for in situ injection and granular activated carbon (GAC) for barrier systems.
• Best applications: PFAS plume stabilization, long-term risk reduction, and sites requiring immediate exposure control.

Integrated Treatment Approach

Many successful remediation strategies combine technologies:

• ISCO for rapid source treatment
• ISCR or bioremediation for long-term plume management
• Activated carbon for containment and risk reduction

This “treatment train” approach provides both immediate impact and long-term performance.

Groundwater Remediation Product Families