TranslateIn Situ Geochemical Stabilization (ISGS)
IET's Proprietary, Exclusively Licenced Technology for NAPL Remediation
What is ISGS?
In Situ Geochemical Stabilization (ISGS) involves the use of modified sodium permanganate (NaMnO₄) developed for in-situ treatment of non-aqueous phase liquids (NAPL). When ISGS reagents are added to a contaminated aquifer, they react with organic (and certain inorganic) constituents of interest present as soil residues (such as NAPL or ganglia).
How It Works
Permanganate and other proprietary reagents are selected based on the particular characteristics of each site and are mixed on-site to form an aqueous solution that can be injected into an aquifer either through existing wells or by direct pressure technology.
As the solution migrates through the treatment area, it oxidizes the contaminants, resulting in partial mass removal. The ISGS technology also reacts with the contaminants in the treated area, coating the NAPL surfaces with stable mineral precipitates that reduce mass flow.
The Process
Various reactions associated with ISGS processes serve to physically crust NAPL and rapidly reduce aquifer permeability. This stabilizes NAPL remnants and accelerates remediation by naturally attenuating dissolved contaminants and components of the contamination plume through source stabilization and flow reduction.
Key Benefits
Environmental Protection
Prevents contaminants from leaching into the environment
In Situ Application
Application and treatment can be done in situ, minimizing site disruption
Cost-Effective
Can be more cost-effective and efficient than conventional stabilization methods
ISGS Technology in Action
Injection Equipment
State-of-the-art direct push and well injection systems for precise ISGS reagent application
Field Application
ISGS treatment being applied at active remediation sites with minimal disruption
NAPL Stabilization
ISGS coating NAPL surfaces with mineral precipitates to reduce contaminant flux
Fixed Well Injections
Using existing wells or newly installed injection points
Direct Push Injections
Mobile direct push technology for rapid site treatment
When chlorinated solvents, coal tar, creosote, and heavy crude oil are released into the environment, they frequently exist as Dense Non-Aqueous Phase Liquids (DNAPL) and represent a long-term secondary source of contamination.
Physical removal or in-situ remediation of DNAPL is not always practicable due to:
- Depth of contamination
- Complex aquifer geology
- Presence of physical surface structures
- Other site-specific limitations
In these cases, ISGS stabilization prevents or slows harmful chemicals from contaminated soil, sediment, and sludge from leaching into the environment. The contaminants are chemically immobilized underground, making them less likely to be released into the environment.
Treatment Approaches for MGP and Creosote Sites
Specialized solutions for dense non-aqueous phase liquid (DNAPL) contamination
ISGS - Preferred Approach
In Situ Geochemical Stabilization (ISGS) is IET's preferred treatment for MGP and creosote sites, offering superior DNAPL encapsulation and containment.
ISS - Complementary Approach
In Situ Stabilization (ISS) with Portland cement provides effective DNAPL stabilization in accessible areas where soil mixing is practical, while ISGS addresses sites with constraints limiting ISS implementation.
Why ISGS for MGP and Creosote Sites?
MGP and creosote sites present unique challenges with dense DNAPL contamination that requires both source area control and aqueous phase treatment. ISGS technology provides superior performance by physically encapsulating NAPL deposits while simultaneously destroying dissolved-phase contaminants, resulting in faster remediation timelines and significant cost savings compared to traditional pump & treat systems alone.
