TranslateDiverse Environmental Remediation Approaches Explained
No single technology works on every site. IET deploys six core in-situ treatment approaches — ISCO, ISCR, bioremediation, EZVI, ISGS, and NAPL treatment — and regularly combines them for the most cost-effective, durable site closure.
In-Situ Chemical Oxidation (ISCO)
Chemical oxidants injected underground destroy organic contaminants through oxidation reactions.
ISCO introduces powerful chemical oxidants — activated persulfate, potassium permanganate, or catalyzed hydrogen peroxide — directly into contaminated subsurface zones. The oxidants react with organic contaminants (TCE, PCE, BTEX, petroleum hydrocarbons), breaking molecular bonds and converting them to carbon dioxide, water, and mineral salts. IET's patented ferric iron-activated persulfate formulation provides sustained oxidation for 12–24+ months after a single injection event, preventing contaminant rebound. IET has performed ISCO at hundreds of sites across all contaminant types.
In-Situ Chemical Reduction (ISCR)
Reductive amendments chemically transform or immobilize contaminants through electron transfer reactions.
ISCR uses reducing agents — zero valent iron (ZVI), ferrous sulfate, or combined formulations — to chemically transform halogenated organic compounds and immobilize heavy metals. Rather than oxidizing contaminants, ISCR reduces them, removing chlorine atoms from chlorinated solvents and converting toxic Cr(VI) to immobile Cr(III). ISCR is particularly effective for mixed plumes containing both chlorinated solvents and metals, and for sites where oxidizing agents may mobilize sensitive site-specific contaminants.
Enhanced Bioremediation & Bioaugmentation
Electron donors and microbial cultures stimulate biodegradation of chlorinated solvents and petroleum by native or introduced microorganisms.
Enhanced bioremediation (ERD) injects electron donor substrates — emulsified vegetable oil (EVO), molasses, or IET's Provect ERD formulations — that stimulate indigenous anaerobic bacteria to sequentially dechlorinate TCE → DCE → vinyl chloride → ethene. Bioaugmentation adds specialized KB-1® or SDC-9® microbial consortia when native organisms are insufficient. Bioremediation is often the most cost-effective long-term approach for dilute chlorinated solvent plumes and is frequently combined with ISCO for source zone mass reduction followed by biological polishing.
Emulsified Zero Valent Iron (EZVI)
Oil-encapsulated ZVI provides both chemical reduction and long-term electron donor for DNAPL source zones.
EZVI is a patented technology developed by NASA and exclusively licensed by IET for DNAPL source zone treatment. An oil-water emulsion encapsulates nano-scale zero valent iron particles, creating a delivery system that partitions into NAPL-phase contamination while also releasing hydrogen as a long-term electron donor for bioremediation. The dual mechanism — immediate chemical reduction of chlorinated DNAPL + sustained biological dechlorination — makes EZVI particularly effective at deep DNAPL source zones where other technologies struggle to achieve complete destruction.
In-Situ Geochemical Stabilization (ISGS)
Modified permanganate solutions are mixed directly into NAPL-impacted soils, destroying soluble mass and stabilizing residual NAPL.
ISGS (licensed exclusively by IET from Evonik) applies modified permanganate reagents through large-diameter soil mixing or HDD injection into NAPL source zones. As the oxidant migrates, it destroys dissolved-phase organics while chemically weathering NAPL residuals — reducing viscosity and flux into groundwater. The MnO₂ precipitate formed during oxidation, combined with other mineral species in the ISGS formulation, accumulates at the NAPL front to further reduce long-term contaminant flux. IET performed the first-of-its-kind HDD-based ISGS injection at a NJ Superfund site.
NAPL Source Zone Treatment
Aggressive source treatment strategies for free-phase DNAPL and LNAPL that drive dissolved-phase plumes.
NAPL (non-aqueous phase liquid) source zones are the primary driver of persistent dissolved-phase groundwater plumes. IET deploys a hierarchy of NAPL treatment approaches based on NAPL type, volume, and depth: For chlorinated DNAPL (TCE, PCE pools): EZVI, high-concentration ISCO, or ISGS. For petroleum LNAPL (gasoline, diesel free product): Bioremediation, ISCO, or combined SVE + in-situ treatment. For complex tar/creosote: ISGS soil mixing with permanent well networks for long-term dissolved-phase management.
Quick Comparison
| Technology | Mechanism | Timeline | Best Contaminants |
|---|---|---|---|
| ISCO | Chemical oxidation | Weeks–months | TCE, PCE, BTEX, DNAPL |
| ISCR | Chemical reduction | Months–years | Chlorinated solvents, Cr(VI) |
| Bioremediation | Microbial degradation | 2–5 years | TCE, PCE, petroleum |
| EZVI | Chem reduction + bio | 1–3 years | Chlorinated DNAPL |
| ISGS | Oxidation + stabilization | Months | NAPL, coal tar, creosote |
| NAPL Treatment | Combined/site-specific | Variable | Free-phase DNAPL/LNAPL |
Common Questions
Not Sure Which Approach Fits Your Contamination?
IET's free AI Site Assessment Tool evaluates your site data and recommends the most appropriate technology combination.
