Injection of strong chemical oxidants into the subsurface to mineralize organic contaminants in place. Common oxidants include sodium and potassium permanganate, sodium persulfate, hydrogen peroxide (Fenton's), and ozone. Used for chlorinated solvents, petroleum hydrocarbons, and select PAHs.
In-Situ Chemical Oxidation delivers oxidant directly to the contaminant in soil pores and groundwater, avoiding excavation and pump-and-treat. The oxidant is mixed with carrier water and injected through direct-push points or permanent wells, sometimes paired with recirculation or fracturing to improve distribution.
Oxidant choice depends on the target contaminant, geochemistry, and required radius of influence. Permanganate is stable and persistent, well suited to chlorinated ethenes (TCE, PCE, DCE). Activated persulfate generates sulfate radicals capable of attacking a wider range of contaminants including benzene and 1,4-dioxane. Fenton's reagent is fast and aggressive but short-lived. ISCO performance is governed by oxidant demand of the soil matrix, contact between oxidant and contaminant (often the binding constraint), and rebound from back-diffusion out of low-permeability zones.
Also known as: ISCO, in-situ chemical oxidation.
In-Situ Chemical Oxidation (ISCO): treatment approach
In-situ chemical oxidation: injection of a chemical oxidant — permanganate, persulfate, or Fenton's reagent — directly into contaminated soil or groundwater to destroy dissolved-phase organic contaminants without excavation.
An ex-situ soil treatment process that heats contaminated soil to volatilize and separate organic contaminants from the soil matrix, after which the liberated vapors are captured and treated, usually in a high-temperature oxidizer.
A thermal desorption configuration where the heat source contacts the soil directly inside the rotary unit, delivering high heat-transfer efficiency and supporting higher treatment temperatures.
A thermal desorption configuration where heat is conducted through the wall of the treatment vessel without combustion gases contacting the soil, producing a concentrated, lower-volume vapor stream suitable for condensation and recovery.
Treatment that heats contaminated soil and groundwater in place, typically with electrical resistance, thermal conduction, or steam injection, to volatilize and recover contaminants without excavation. Used where excavation is impractical or where the contaminant zone sits beneath active infrastructure.