Enhanced Aerobic Biodegradation and In Situ Chemical Oxidation Used to Remediate Difficult Geology

Project Highlights

  • Significant cost savings to client achieved using enhanced aerobic biodegration and In Situ Chemical Oxidation (ISCO)
  • Highly successful project, despite difficult caliche soil (sedimentary rock) found specifically in desert regions
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Project Summary

An active service station in downtown Las Vegas, Nevada was contaminated with high levels of BTEX, TPHg, and TPHd in the soil and groundwater.

REGENESIS® partnered with Antea® Group, a leading environmental firm, to complete three ISCO injections. For the first injection, approximately 310 lbs. of PersulfOx® and 45 lbs. of ORC Advanced® were mixed with 211 gallons of water at a 15 percent solution for a total of 226 gallons of solution injected per well.

A total of 3,100 lbs. of PersulfOx, 450 lbs. of ORC Advanced, and 2,260 gallons of solution were injected during the second and third injection events. The injection pressures ranged from 35 to 40 pounds per square-inch (psi) with flow rates ranging from 6 to 10 gallons per minute. Closely monitoring flow rates and injection pressure allowed REGENESIS to successfully apply the products without any surfacing occuring.

Technology Description

PersulfOx is an advanced in situ chemical oxidation (ISCO) reagent that destroys organic contaminants found in groundwater and soil through abiotic chemical oxidation reactions. It is an all-in-one product with a built-in catalyst which activates the sodium persulfate component and generates contaminant-destroying free radicals without the costly and potentially hazardous addition of a separate activator. The patented catalyst enhances the oxidative destruction of both petroleum hydrocarbons and chlorinated contaminants in the subsurface.

ORC Advanced is an engineered, oxygen release compound designed specifically for enhanced, in situ aerobic bioremediation of petroleum hydrocarbons in groundwater and saturated soils. ORC Advanced provides remediation practitioners with a significantly faster and highly effective means of treating petroleum contaminated sites.


Reduction of BTEX After PersulfOx and ORC Advanced Injection
Following three ISCO injection events, significant reductions in BTEX compounds continue to be observed in source area groundwater monitoring well MW-12. A reduction from 7,400μg/L to 250μg/L and declining was observed. Additionally, increased sulfate concentrations persist in groundwater at monitoring well MW-12 following the injections, indicating that groundwater geochemical changes are still occurring as a result of the injection of PersulfOx, and ORC Advanced. As a result of the rapid successful reduction of BTEX, TPHg, and TPHd, the client will be petitioning for “No Further Action”.

About the Consultant

Antea Group is a multinational environmental consulting firm that combines innovation with integrity, integrates local support with global perspectives and unites technical expertise with superior project management to deliver results focused sustainable business solutions for clients worldwide. Antea Group’s experienced environmental management professionals accommodate client-specific goals, stakeholder expectations and regulatory requirements by providing comprehensive strategies designed to reduce environmental footprints, mitigate safety risks, protect against engineering failures and minimize social impacts.