Combined Remedy Leads to Site Closure

Estimated Reading Time: < 1 minute

Case study highlights:

  • Significant contaminant reductions achieved in both the source area and core plume
  • 8-10 weeks of time saved compared to alternative approaches
  • $500,000 saved in project costs compared to alternative Electrical Resistance Heating (ERH) approach being considered

This case study reviews an active Underground Storage Tank (UST) case with the Arizona Department of Environmental Quality (ADEQ), where the site needed to meet ADEQ closure levels quickly in order to seek risk-based closure as part of a property transaction. After performing remedial assessment activities, the consulting firm Antea Group selected a combined remedy approach from REGENESIS, which included soil mixing using RegenOx® and H2O2 in the source zone and ISCO injections using PersulfOx® in the core plume. The solution from REGENESIS achieved ADEQ Closure levels for the site and now Antea Group is seeking a risk-based closure.

Combined Remedy Chosen for FDEP Innovative Technologies Program

Estimated Reading Time: < 1 minute

Case study highlights:

  • An in situ combined remedy approach that was chosen as the most technically-feasible and cost-effective strategy in a competitive bid scenario for the Florida Department of Environmental Protection’s Innovative Technologies Program
  • High level of site complexity – flowable fill layer present over the treatment area, difficult geology (i.e., clays and limestone), and close proximity to structures, utilities and a roadway
  • Use of PlumeStop, RegenOx, and ORC Advanced to successfully address a large BTEX plume

A former gas station site in Taylor County Florida had undergone prior remedial efforts over the years. The Florida Department of Environmental Protection (FDEP), through its Innovative Technologies Program, engaged the environmental consulting firm, Advanced Environmental Technologies LLC (AET) to design an alternative combined remedial approach employing PlumeStop®, RegenOx® and ORC Advanced®, to sorb, degrade, and destroy the existing petroleum contaminant plume. Prior to full-scale implementation, treatment of this site began with a thorough Design Verification Testing (DVT).

RegenOx Application Quickly and Efficiently Lowered Diesel Range Organics (DRO) to Below ADEC Requirements

Estimated Reading Time: 2 minutes

Project Highlights

  • Two applications of RegenOx® reduced contaminants to a level below the Alaska Department of Environmental Conservation (ADEC) standards to protect against migration to groundwater
  • Completed in 8 weeks, restoring agriculture viability
  • Soil was safely and efficiently cleaned preventing fuel from contaminating a nearby sensitive receptor
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diesel remediation

Project Summary

A Hydaburg site in Alaska, owned by Alaska Power and Telephone, previously housed diesel fuel generators and is now being converted into a hydro-electric plant. The land was contaminated by a diesel fuel spill requiring remediation. Approximately 1,000 cubic yards of soil were impacted and the starting concentrations of DRO were approximately 1 500 ppm. The goal was to reduce concentrations to below the ADEC standard of 230 ppm.

Due to the cold weather encountered during this project and the sensitive infrastructure in the area, it was important that the technology work effectively in less than ideal conditions. Also, the technology could not be corrosive nor generate excess heat. RegenOx, produces minimal heat and pressure, is non-corrosive, and works well at any temperature above freezing making it ideal for this project. Additionally, RegenOx is a chemical oxidant which quickly and effectively destroys a range of contaminants-in this case, DRO. The soil was screened with a trommel and RegenOx was mixed in a cement truck before being sprayed onto the soil. RegenOx was applied twice, with the applications spaced a week apart. This site required 20 lbs of RegenOx per cubic yard, in total 20,000 lbs.

Technology Description

RegenOx is a percarbonate-based in situ chemical oxidation technology that rapidly destroys petroleum hydrocarbons and chlorinated contaminants through powerful chemical reactions. It directly oxidizes contaminants while a catalytic component generates oxidizing free radicals to destroy the target compounds.

Results

After two applications of RegenOx, the concentrations of DRO went from 1,500 ppm to below 125 ppm, satisfying the ADEC requirement of below 230 ppm, within 8 weeks. After the remediation treatment, the soil was spread out, grass was planted and is now growing at the Hydaburg site, attesting to the renewed health of the soil.

Remediation of Chlorinated Hydrocarbons at Manufacturing Facility, UK

Remediation of Chlorinated Hydrocarbons at Manufacturing Facility, UK

Estimated Reading Time: 3 minutes

AECOM successfully applied a phased treatment train solution for chlorinated solvents under an operational manufacturing facility. After an initial Dual Phase Extraction (DPE) phase, REGENESIS and AECOM devised a remedial design based on the updated Conceptual Site Model including In Situ Chemical Oxidation (ISCO) using RegenOx®, and Enhanced Reductive Dechlorination (ERD) using HRC®, to treat the residual contamination in groundwater.
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Innovative Combined Amendment Approach Successfully Applied to Treat PHC Levels

Estimated Reading Time: 2 minutes

Project Highlights

  • Site previously treated with a series of RegenOx® and ORC Advanced® amendments significantly reduces plume concentrations. Remaining hot spot was then treated with turn-key injection application of PersulfOx® and ORC Advanced technologies bringing closure to facility
  • Successful turn-key treatment of offsite hot spot completed within five days
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antea

Project Summary

An active gas station, identified by the State of Washington Department of Ecology as one of five LUST sites within one mile of Vancouver’s three groundwater monitoring wells, had entered into the state’s Voluntary Cleanup Program (VCP) in 2006 subsequent to shutdown of the onsite air-sparge/vapor extraction (AS/VE) system. This system had historically been employed at the site to supply oxygen for remedial purposes and address subsurface contamination that was first discovered beneath the dispenser islands in 1993. While prior applications of RegeneOx and ORC Advanced were effective in mitigating onsite contamination, PHC levels remained above MTCA criteria offsite hindering achievement of regulatory closure.

Antea® Group—the environmental consulting firm charged with remediation—partnered with REGENESIS® to implement a remedial strategy and technical design, which included the turn-key injection application of PersulfOx and ORC Advanced technologies to address petroleum hydrocarbons (PHCs) using an in situ chemical oxidation (ISCO) and enhanced aerobic remediation approach. The hot spot injection application included one event of PersulfOx coapplied with ORC Advanced, using direct push technology (DPT) injection points throughout the 3200 sq. ft. treatment area through 40 DPT injection points.

Technology Description

RegenOx – An injectable two-part advanced in situ chemical oxidation (ISCO) reagent that combines a solid sodium percarbonate-based alkaline oxidant (Part A) with a liquid mixture of sodium silicates, silica gel and ferrous sulfate (Part B), resulting in a powerful technology that treats and destroys a wide range of target contaminants including both petroleum hydrocarbons and chlorinated compounds.

PersulfOx – An advanced ISCO reagent and all-in-one product with a built-in patented catalyst destroys organic contaminants found in groundwater and soil through abiotic chemical oxidation reactions.

ORC Advanced – An engineered, oxygen-release compound designed specifically for enhanced, in situ aerobic bioremediation of petroleum hydrocarbons in groundwater and saturated soils. ORC Advanced produces a controlled release of molecular oxygen accelerating aerobic biodegradation processes up to 100 times f aster than natural degradation rates.

Results

For the final application event, following five on-site working days, REGENESIS completed the hot spot application process during which 9,753 lbs. of PersulfOx and 2,240 lbs. of ORC Advanced were applied to the designated treatment area. First quarter sampling results post-application showed concentrations below MTCA criteria. Following three quarters of monitoring, remediation of this site will be complete.

About the Client

Antea Group is an international engineering and environmental consulting firm specializing in full-service solutions in the fields of environment, infrastructure, urban planning and water. With more than 3,000 employees in over 100 offices around the world, Antea Group serves clients ranging from global energy companies and manufacturers to national governments and local municipalities.