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What is in-situ chemical oxidation (ISCO)?

In-situ chemical oxidation (ISCO) is an environmental remediation technique where chemical oxidants such as persulfate, permanganate, or hydrogen peroxide are injected into contaminated soil and groundwater to destroy organic contaminants like TCE, PCE, and petroleum hydrocarbons in place — without excavation.

What contaminants can IET remediate?

IET specializes in TCE remediation, chlorinated remediation, and comprehensive environmental treatment. We remediate chlorinated solvents (TCE/trichloroethylene, PCE/perchloroethylene, DCE, vinyl chloride), petroleum hydrocarbons (BTEX, gasoline, diesel, MTBE), heavy metals (chromium, lead), NAPL, DNAPL, PAHs, creosote, and mixed contamination using ISCO, ISCR, bioremediation, EZVI, and ISGS technologies.

How long does environmental remediation take?

Remediation timelines vary by technology and site conditions. ISCO can achieve significant contaminant reduction in weeks to months. Enhanced bioremediation typically requires 2–5 years of active treatment. IET's patented ferric iron-activated persulfate provides sustained treatment lasting over 2 years to prevent contaminant rebound.

What states does IET provide environmental drilling services?

IET provides environmental and geotechnical drilling services nationwide including Pennsylvania, Ohio, North Carolina, South Carolina, Texas, Florida, New Jersey, New York, Virginia, Georgia, Tennessee, Indiana, Illinois, and more. IET operates 50+ specialized rigs including CME, Geoprobe, AMS, and barge drilling equipment.

What is in situ chemical oxidation (ISCO)?

In situ chemical oxidation (ISCO) is an environmental remediation technique where chemical oxidants such as persulfate, permanganate, or hydrogen peroxide are injected directly into contaminated soil and groundwater to chemically destroy organic contaminants — without excavation. ISCO converts hazardous compounds like TCE, PCE, and BTEX into harmless end products such as carbon dioxide and water.

What contaminants can ISCO treat?

ISCO effectively treats chlorinated solvents (TCE, PCE, 1,1,1-TCA, carbon tetrachloride), petroleum hydrocarbons (BTEX, gasoline, diesel, heating oil), PAHs, MTBE, phenols, and SVOCs. IET's ferric iron-activated persulfate system is particularly effective at treating DNAPL source zones and dissolved plumes.

How long does ISCO remediation take?

ISCO typically achieves significant contaminant reductions in weeks to months — much faster than biological methods. IET's patented ferric iron-activated persulfate technology also supports sustained secondary bioremediation for over 2 years after injection, preventing contaminant rebound that plagues conventional ISCO.

What is persulfate activation and why does it matter?

Persulfate activation converts stable persulfate into powerful free radicals (sulfate radical SO₄•⁻ at 2.60V) that destroy contaminants. IET uses ferric iron activation, which simultaneously generates ferrate (Fe⁶⁺ at 2.20V) for a multi-oxidant attack on contaminants. This patented approach also generates iron and sulfate that sustain biological treatment for years after the initial injection event.

What is contaminant rebound and how does IET prevent it?

Contaminant rebound occurs when concentrations rise again after ISCO treatment ends, as contaminants desorb from the aquifer matrix. IET's ferric iron-activated persulfate technology uniquely prevents rebound by generating iron and sulfate that serve as electron acceptors for bacteria — sustaining biological degradation for over 2 years after injection.

How much does ISCO remediation cost?

ISCO costs vary by site size, contaminant type, depth, and geology. Small source-area treatments may run $50,000–$150,000; larger plume treatments can exceed $500,000. IET provides free site evaluations and cost estimates. Call 888-721-8283 or use our AI Site Assessment Tool to get started.

Does IET provide ISCO services nationwide?

Yes. IET has completed ISCO remediation projects in over 40 states including Pennsylvania, Ohio, North Carolina, New Jersey, Texas, Florida, Illinois, Indiana, Tennessee, Georgia, and many more. We operate 50+ injection rigs and can mobilize nationwide.

Remediation Technology

Persulfate Activation & ISCO Remediation Services — In Situ Chemical Oxidation

IET's patented ISCO technologies rapidly destroy TCE, PCE, BTEX & petroleum contaminants in soil and groundwater — achieving site closure faster with sustained bioremediation to prevent rebound. Request a free evaluation.

How ISCO Chemical Oxidation Works

ISCO involves the injection of chemical oxidants into contaminated soil and groundwater to chemically convert hazardous contaminants into non-hazardous or less toxic compounds, primarily carbon dioxide and water.

The process accelerates the natural oxidation process, achieving in months what might otherwise take decades through natural attenuation.

ISCO Oxidant Types

Permanganate: Effective for chlorinated solvents and PAHs
Hydrogen Peroxide: Rapid oxidation of petroleum hydrocarbons
Persulfate: Long-lasting oxidant for sustained treatment
Ozone: Powerful oxidant for rapid response
Ferrate (Fe⁶⁺): Supercharged iron species generated by IET's ferric iron-activated persulfate system — dual-action oxidant and coagulant with 2.20V oxidation potential for direct contaminant destruction and simultaneous aquifer improvement

Target Contaminants

Petroleum Hydrocarbons

• BTEX compounds
• Gasoline
• Diesel fuel
• Heating oil

Chlorinated Solvents

• TCE / PCE
• 1,1,1-TCA
• Carbon tetrachloride
• Chloroform

Other Compounds

• PAHs
• MTBE
• Phenols
• SVOCs

Key Advantages

Rapid Treatment

Achieves significant contaminant reduction in weeks to months, much faster than biological methods.

In Situ Application

No excavation required - treatment occurs underground with minimal site disruption.

Complete Destruction

Converts contaminants to harmless end products rather than transferring them elsewhere.

Cost-Effective ISCO

Reduces long-term monitoring costs and accelerates site closure timelines.

Advanced Persulfate Chemistry & Multiple Oxidation Mechanisms

IET employs ferric iron-activated persulfate technology that generates multiple powerful oxidants simultaneously, providing superior contaminant destruction and long-term performance through sustained secondary bioremediation.

Activation Mechanism

S₂O₈^-2 + Fe⁺³ → Fe^{(+4 to +6)} + SO₄^2- + SO₄^2-•

Ferric iron activation generates supercharged iron (ferrate) and persulfate radicals

Persulfate Radical (SO₄•^-)

Primary oxidant - powerful free radical with 2.60V oxidation potential

Ferrate (Fe⁺⁶)

Supercharged iron species with 2.20V potential - direct contaminant oxidation

Persulfate (S₂O₈^-2)

Extended oxidation capacity - 2.01V potential for long-term treatment

Oxidation Potential Comparison

Oxidant	Oxidation Potential (Volts)
Fluorine (F₂)	2.87
Hydroxyl radical (OH•)	2.80
Persulfate radical (SO₄•^-)	2.60
Ferrate (Fe⁺⁶)	2.20
Ozone (O₃)	2.08
Persulfate (S₂O₈^-2)	2.01
Hydrogen peroxide (H₂O₂)	1.78
Permanganate (MnO₄^-)	1.68
Chlorine (Cl₂)	1.49

Yellow highlighted rows: Multiple oxidants generated simultaneously by IET's ferric iron-activated persulfate system

Practiced ISCO Chemistries

Activated Persulfate: Ferric iron activation for multiple oxidants

Permanganate: Direct oxidation with long persistence

Peroxides: Hydroxyl radical generation

Combined Oxidation: Persulfate + peroxide synergy

⚠️Contaminant Rebound: A Critical ISCO Challenge

The most significant problem with conventional ISCO is contaminant rebound. Research analyzing 59 chlorinated-solvent sites shows that most ISCO treatments achieve initial contaminant reduction but experience rebound within a few years when oxidants are exhausted and contaminants desorb from the aquifer matrix.

Contaminant rebound comparison chart: Enhanced Bioremediation vs ISCO Chemical Oxidation — temporal concentration records from 59 chlorinated solvent DNAPL sites (McGuire et al 2006)

Source: McGuire et al (2006) - Analysis of 59 DNAPL sites showing Chemical Oxidation (right) exhibits more rebound than Enhanced Bioremediation (left)

IET's Solution: Enhanced Bioremediation Through Ferric Iron Chemistry

IET's ferric iron-activated persulfate technology manages rebound through sustained secondary biological treatment lasting >2 years:

Iron as Terminal Electron Acceptor: Ferric iron (Fe³⁺) accepts electrons from facultative bacteria, reducing to Fe²⁺ which can reactivate persulfate in redox cycling
Sulfate as Electron Acceptor: Generated sulfate (SO₄^2-) supports sulfate-reducing bacteria for long-term contaminant degradation
Degradation Intermediates as Electron Shuttles: Oxidation products and humic acids facilitate Fe³⁺ reduction to Fe²⁺, sustaining treatment
Pyrite Formation: Ferrous iron + sulfide → FeS₂ (pyrite) provides reactive sites for contaminant precipitation and long-term removal
Multi-Year Longevity: Iron remains active for years (vs oxygen release compounds exhausted in months)

Persulfate Resources

Explore our comprehensive resources on persulfate-based oxidation technologies, including case studies, technical documentation, and patented innovations.

IET's ISCO Approach

Our experienced team designs customized ISCO programs based on site-specific conditions, contaminant types, and remediation goals. We conduct thorough site characterization, treatability studies, and pilot testing to optimize oxidant selection and delivery methods.

With over 28 years of experience and 1,500+ remediation events, IET delivers proven ISCO solutions that achieve regulatory closure efficiently and economically.