In Situ Remediation of Petroleum Hydrocarbons at Rail Depot, Bristol, UK

Estimated Reading Time: 2 minutes

Surface petroleum hydrocarbon contamination had resulted from historic and on-going leaks at a train maintenance depot near Bristol, where trains were stabled overnight. REGENESIS was asked to design a remedial approach for a hotspot treatment of this contamination within one of the rail tracks.ORC Advanced Socks were installed in wells for the treatment of the dissolved phase contaminants in groundwater. The quick application showed the ease
 of installation, with only validation of the groundwater required to provide evidence of treatment. The ORC Advanced provided a >90% reduction in the groundwater within the hotspot area.

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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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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.

Efficient Application of Combined Amendments Reduces PHC Concentrations Below Washington MCTA Levels

Estimated Reading Time: 3 minutes

Project Highlights

  • In Situ injection application of PlumeStop® Liquid Activated Carbon™ and ORC Advanced® brings closure to facility identified as Leaking Underground Storage Tank (LUST) site
  • REGENESIS® Remediation Services (RRS) used a multi-point approach to efficiently inject the combined amendments, completing the application within 24 hours
  • PHCs in groundwater and soil reduced below Washington Department of Ecology’s Model Toxics Control Act (MTCA)
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Project Summary

An active gas station in Bothell, Washington was listed as a LUST site by the State of Washington Department of Ecology after two subsurface investigations detected petroleum hydrocarbon (PHC) impacted soil and groundwater. Entering into the state’s Voluntary Cleanup Program (VCP) in 2001, the site continuously failed to meet regulatory requirements defined in the MTCA, despite several years of cleanup efforts using a soil vapor extraction (SVE) system and an air sparge (AS) system to remove contaminant concentrations from beneath the site. Charged with remediation, Antea® Group partnered with REGENESIS to implement a solution, which included in situ injection applications of PlumeStop and ORC Advanced technologies.

REGENESIS injected approximately 200 gallons of PlumeStop using strategically placed point locations to rapidly reduce contaminant concentrations. Direct Push Technology (DPT) was employed to advance injection points throughout the treatment zone. The following day, the solution was increased, for a total of 835 gallons of PlumeStop solution (as applied with water) injected within the targeted treatment interval to deliver the full volume of remediation ammendment and complete the application on schedule. A total of nine (9) PlumeStop DPT injection points were cleared to 5 ft. bgs pre-injection.

Additionally, 120 lbs. of ORC Advanced were applied in cleared boreholes via a backfilling method, which involved drilling to the target depth, retracting the rods and pouring the ORC Advanced slurry down open boreholes to approximately 5 ft. bgs in order to properly abandon points.

Technology Description

PlumeStop – An innovative groundwater remediation technology designed to address the challenges of excessive time and end-point uncertainty in groundwater remediation. PlumeStop is composed of very fine particles of activated carbon (1-2μm) suspended in water through the use of unique organic polymer dispersion chemistry. Once in the subsurface, the material behaves as a colloidal biomatrix binding to the aquifer matrix, rapidly removing contaminants from groundwater, and enhancing permanent contaminant biodegradation.

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

During the course of the injection and at the end of the application, increases in groundwater levels, ORP (oxidation reduction potential), and dissolved oxygen were observed in monitoring wells in the treatment area. The successful application of both technologies was achieved within approximately 24 hours, despite the challenging glacial till geology known to the region. With field modifications, RRS was able to not only mitigate surfacing issues by switching to injection via injection-well application, but also achieve the desired distribution of the remediation substrate in the subsurface. The first quarter sampling results indicate that the contaminant concentrations are at non-detect. Following monitoring events over the next three quarters, this site will be closed and issued a No Further Action (NFA) from the Washington Department of Ecology.

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.

Remediation of Impacted Groundwater on a Busy Construction Site, UK

Estimated Reading Time: 2 minutes

REGENESIS was asked to provide a remedial solution to mitigate against the off-site migration of the contaminated groundwater. We designed a PlumeStop barrier and was subsequently employed as subcontractor on the works. The barrier injections were made along the downgradient boundary of the site, targeting the groundwater in a gravel formation at 2 – 5m BGL. On this site, PlumeStop was co-injected with ORC-Advanced to enhance the aerobic biodegradation processes in the subsurface.Read More

Contaminant Concentrations at an Active Gas Station Reduced by 90% Using PersulfOx® and ORC Advanced®

Estimated Reading Time: 2 minutes

REGENESIS Uses an Outside-In Application to Push 30-Year Old LUST Case to Closure in Remote Region of Arizona

Project Highlights

  • Innovative “Outside-In” approach incorporated injection design working from perimeter of the treatment area first, and progressively working toward the center
  • First event application completed within seven days with a second event completed in nine days the following month without disruption to active site
  • Closely managed injection wells to ensure proper distribution and avoid surfacing
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Project Summary

An active gasoline station in Springerville, AZ was listed as a hazardous Leaking Underground Storage Tank (LUST) site by the state of Arizona. After 30 years of unsuccessful remediation using a number of approaches, REGENESIS Remediation Services (RRS) was contacted to perform two separate injection events approximately one month apart. Both events included injections at 15 injection points over a range of depths. The first round of injections included a combination of PersulfOx and ORC Advanced. The second round of injections contained only PersulfOx.

During both injections PersulfOx and ORC Advanced were successfully applied within the treatment area and at the targeted treatment interval of 18 to 60 ft. bgs. Low to moderate injection pressures and application flow rates were observed at each of the injection well locations, indicating good distribution of the amendments. Increases in dissolved oxygen, conductivity, pH, and oxidation-reduction potential were observed, indicating good distribution and influence of the PersulfOx and ORC Advanced remediation chemistry.

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.

Results

Since the two injections have been completed, three rounds of groundwater monitoring have been performed. Benzene concentrations have been reduced by 90% to 20 μg/L. A closure request has been submitted by the client awaiting regulatory approval.