Proactive Combined Remedies incorporate multiple treatment processes into the remedial design to:

1. Increase remediation effectiveness, reduce clean-up time, and minimize cost;

2. Enhance transfer of contaminants into the aqueous phase for treatment by conventional in-situ remediation technologies; and

3. Accelerate regulatory approval and reduce costs.

paul dombrowski, p.e.
Senior Remediation Engineer

Permanganate (ISCO) + ZVI & EVO (PRB) Combined Remedy

Summary: a private development manufacturing site required
voluntary onsite remediation. TCE, petroleum hydrocarbons, and metals impacted subsurface soils and groundwater to depths of 60 ft bgs. ISOTEC designed and implemented the following combined remedies in parallel with site redevelopment:

Soil excavation: >20,000 tons,

Permanganate ISCO: allowed oxidant advection in limited
access areas,

ZVI + EVO Permeable Reactive Barrier installed via DPT
injections at property boundary,

Coordination between owner, architect, regulatory agency,
and remediation team,

Project achieved conditional Track 1 Cleanup.

In Situ Chemical Oxidation + Enhanced In-Situ Dechlorination

Summary: Combined remediation for groundwater impacted by Carbon Tetrachloride (up to 17 mg/L) & PCE (up to 200 mg/L).


Phase 1: In-Situ Chemical Oxidation with Activated Sodium Persulfate

Achieved 80% to 97% reduction of Carbon Tetrachloride.

Phase 2: Enhanced In-Situ Dechlorination

Carbon Tetrachloride → abiotic dechlorination → Chloroform (CF)

Carbon substrate (ELS)

KB-1 Plus [CF formulation] – cultured on a mg/L concentration of CF

Bacteria degraded CF to dichloromethane & non-toxic products

Persulfate breakdown product (sulfate) reduced to FeS for abiotic dechlorination

In Situ Chemical Oxidation + biosparging

Summary: This combined remedy was implemented to rapidly remediate BTEX impacts from historic UST releases.

Phase 1: Design and Install Three Directionally-Placed Horizontal Remediation Wells Beneath Buildings. 

Phase 2: ISCO with MFR for BTEX Desorption + Oxygen Byproduct (Oxidation).

Phase 3: Biosparging to Remediate Residual BTEX Impacts in Saturated Zones.

bioremediation enhanced with surfactants

Summary: Environmental remediation at a former metal tool manufacturing site conducted to address mineral oil LNAPL, TCE, DCE VC, and petroleum hydrocarbon impacts. The project goal was to accelerate intrinsic bioremediation of subsurface contaminants.

A customized surfactant was added to injected sodium lactate to break up LNAPL, dissolve CVOCs in LNAPL, and utilized LNAPL as an electron donor.      

After application, the site transitioned to Temporary Solution Status with limited monitored natural attenuation. 

surfactant-Enhanced In-situ chemical oxidation

Summary: Surfactants were added to permanganate injected in the source area (3 to 23 ft bgs) for in-situ treatment of PCE impacts in soil and groundwater.

Sequenced downgradient ISCO injections were completed before surfactant injections.


Highest PCE concentrations were rapidly reduced by > 99%, from 7,000 ug/L to 32 ug/L.

In Situ Chemical Oxidation + Enhanced In Situ Dechlorination

Summary: An urban redevelopment site was impacted by chlorinated VOCs in soil and groundwater, including high PCE concentrations in the source area.

ISCO injections utilizing Modified Fenton’s Reagent were applied to desorb contaminants from soil and destroy them via oxidation.

ZVI-ERD injections were then implemented using an ‘outside in’ approach to apply small micron zero valent and glycerol for longer lasting bioaugmentation.