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Combined Remedies Replace Costly Mechanical Remediation Systems
RegenOx® and ORC® Advanced Treat MTBE/TBA at Five Active California Service Stations
Project Highlights
- In Situ chemical oxidation (ISCO), enhanced aerobic biodegradation replaced costly mechanical remediation systems.
- Underground infrastructure required extra precaution when applying remediation reagents on each site.
- Site closure or review of site closure at all five service stations
Project Summary
Five sites in Orange County, CA were selected for remediation using ISCO and enhanced aerobic biodegradation. All of the selected sites were gasoline service stations that were contaminated with low levels of hydrocarbons methyl tertiary butyl ether (MTBE) and elevated levels of the MTBE biodegradation daughter product tertiary butyl alcohol (TBA). The initial remediation approach consisted of soil vapor extraction, air sparging and dual phase extraction; however, contaminant concentrations remained elevated, impeding regulatory closure.
The decision was made to transition from mechanical-based remediation systems using a combination of ISCO and enhanced aerobic biodegradation to achieve site closure criteria with various regulatory agencies.
Remediation Approach
Initial mass reduction was achieved using mechanical systems, however concentrations remained too high for regulatory closure. The goal was to reduce the remaining levels of petroleum hydrocarbons, MTBE and TBA using RegenOx and ORC Advanced. The service station included up to three direct-push injection applications of the reagents into areas where underground infrastructure was present on each site. RegenOx and ORC Advanced are both highly compatible with subsurface infrastructure so it was more of a challenge from a physical injection vantage. O&M strategy required monitoring of REDOX and microbial shifts. All five sites have been closed or under review for closure under the local regulatory agencies.
Advanced Formula Oxygen Release Compound (ORC Advanced®) is a proprietary formulation of food-grade, calcium oxyhydroxide that produces a controlled-release of molecular oxygen for periods of up to 12 months upon hydration.
Technology Description
RegenOx is an advanced chemical oxidation technology that destroys contaminants through powerful, yet controlled chemical reactions and not through biological means. This product maximizes in situ performance while using a solid alkaline oxidant that employs a sodium percarbonate complex with a multi-part catalytic formula.
ISCO Treatment Achieves Closure on Arizona Superfund Site
Benzene Contamination Treated to Non-Detect with Single PersulfOx® Application
Project Highlights
- Previous remediation attempts included soil vapor extraction coupled with groundwater pump and treat/air sparging.
- PersulfOx was applied via gravity-feed through existing remediation wells.
- Single application of PersulfOx resulted in benzene reductions of 1,000 ug/L to non-detect.
- Site closure achieved
Project Summary
Persistent benzene contamination at an Arizona Superfund Site kept the state regulatory agency from closing the site. The City of Tucson maintenance yard contained low residual concentrations of benzene around 1,000 ug/L in a single well. An initial remediation approach used soil vapor extraction coupled with groundwater P&T and air sparging, however results did not meet site closure criteria.
When considering alternatives, the State of Arizona wanted to be efficient by using the existing remediation wells. As a result, Regenesis worked with the state to design a PersulfOx application using the existing infrastructure. Regenesis worked with the state to design and assist with the application of PersulfOx® using the existing remediation wells. After one application, benzene contamination levels were non-detect in the offending well and site closure was achieved.
Remediation Approach
The treatment approach was a trial by the State of Arizona to apply PersulfOx via gravity-feed directly into the existing remediation wells to target residual benzene concentrations. By using the existing in situ infrastructure, the cost of the one-time PersulfOx application was less than $15/cubic yard.
Technology Description
PersulfOx is a sodium persulfate-based chemical oxidation technology which destroys both hydrocarbon and chlorinated solvent-type contaminants in the subsurface. PersulfOx contains a built-in catalyst which activates the persulfate component and generates contaminant-destroying free radicals without the need for the addition of a separate activator.
Dissolved-Phase Petroleum Hydrocarbons in Clay Treated with Enhanced Aerobic Biodegradation Using ORC® Advanced
Site Closure Pending Post-Treatment at California Retail Store Location
Project Highlights
- Dual-phase extraction had been used on-site, however BTEX contamination concentrations remained high.
- Enhanced aerobic biodegradation using ORC Advanced applied via directinjection into clay soils.
- Post-ORC Advanced Application, BTEX groundwater concentrations below 10 ug/L.
Site closure pending.
Project Summary
The Cambria General Store in Central California had a history of petroleum hydrocarbon contamination. Dual-phase extraction had been used in the past to treat the site and a total of 130 pounds of petroleum hydrocarbons were removed. However, contamination levels remained above regulatory levels. Contaminant concentrations included: benzene at 310 ppb, toluene at 8,000 ug/L, ethylbenzene at 2,700 ug/L and xyelene at 12,000 ug/L. THPg levels were measured as high as 14,000 ug/L on-site. The site was successfully treated with ORC Advanced which reduced BTEX groundwater concentrations below 10 ug/L. Site closure is pending.
Remediation Approach
ORC Advanced was used to treat the residual dissolved-phase groundwater to California’s low threat groundwater levels. It was applied to two areas within a 1,200-square-foot treatment area. A total of 14 injection points were used to apply a total of 3,000 pounds of ORC Advanced with injection spacing of 7.5 feet on center.
Technology Description
ORC Advanced is a proprietary formulation of food-grade, calcium oxy-hydroxide that produces a controlled-release of molecular oxygen for periods of up to 12 months upon hydration. This newly available source of oxygen is available for aerobic microorganisms to metabolize along with the unwanted petroleum hydrocarbons.
Regenesis Remediation Services™ – LNAPL Recovery at an Active Gas Station
Combined Treatment Remedies Reduce Contamination Concentrations at Michigan Service Station
Regenesis Remediation Services (RRS) was contracted to remediate a residual LNAPL and dissolved-phase petroleum plume from historic gasoline and diesel fuel releases at an active service station. RegenOx PetroCleanze™ (PetroCleanze) was chosen as the primary remediation technology to facilitate the recovery of residual LNAPL and chemically oxidize contaminants without negatively impacting sensitive infrastructure.
The design called for three (3) application events using PetroCleanze, with Oxygen Release Compound (ORC®) Advanced applied during the final application event in a down-gradient plume cut- off barrier, to promote the enhanced aerobic biodegradation of dissolved-phase petroleum hydrocarbons. Eight (8) injection/extraction wells and 28 direct-push technology (DPT) injection points were used to apply the remediation reagents in the silty-sand aquifer and smear zone. Vacuum extraction was conducted between PetroCleanze applications to recover residual freephase petroleum hydrocarbons liberated from the soils. Reagent distribution monitoring confirmed PetroCleanze was present throughout the targeted source area during each application event.
Prior to the first PetroCleanze application event, no measurable free product was observed at this site since 2006. Less than twenty-four hours after the first PetroCleanze application event, LNAPL up to three inches thick was observed in four of the eight wells. After completing the third application and extraction event, LNAPL was not observed in any wells on site, and BTEX concentrations in groundwater were showing reductions for the first time since the fuel releases first occurred. A total of 2,160 pounds of RegenOx PetroCleanze and 1,120 lbs. of ORC Advanced were injected.
Regenesis Remediation Services™ – LNAPL Recovery & In Situ Chemical Oxidation
Combined Treatment Remedies Reduce Contamination Concentrations at a Former Service Station
Regenesis Remediation Services (RRS) was contracted to remediate a dissolved-phase and residual LNAPL petroleum hydrocarbon plume resulting from historic petroleum fuel releases at a former service station. RegenOx® PetroCleanze™ (PetroCleanze) was chosen as the primary remediation technology in addition to Oxygen Release Compound (ORC®) Advanced, to facilitate recovery of residual LNAPL and chemically oxidize contaminants without negatively impacting sensitive infrastructure. ORC Advanced was applied during the second PetroCleanze application to promote the enhanced aerobic bioremediation of dissolved phase petroleum hydrocarbons.
Eighteen direct-push injection points were used to apply the reagents in the silty sand aquifer and saturated soil over the course of two application events. Vacuum extraction was conducted after each PetroCleanze application to recover residual free-phase petroleum hydrocarbons liberated from the soils. Reagent distribution monitoring during the application events confirmed PetroCleanze was present across the targeted source area. Remediation chemistry was applied via direct-push injection points with a bottom-up approach from 5 to 15 feet below ground surface (bgs). A total of 4,470 pounds (lbs.) of RegenOx PetroCleanze and 720 lbs. of ORC Advanced were injected throughout the course of the two applications.
Regenesis Remediation Services™ – LNAPL Recovery with RegenOx®
Remediation of Residual LNAPL and a Dissolved-Phase Plume at a Former Gasoline Service Station
Regenesis Remediation Services (RRS) was contracted to remediate a residual LNAPL and dissolved phase petroleum plume from a historic fuel release at this former gasoline service station. RegenOx PetroCleanze™ (PetroCleanze) was chosen as the primary remediation technology to facilitate recovery of residual LNAPL and chemically oxidize contaminants without negatively impacting sensitive infrastructure.
Twenty-six (26) direct-push injection points were used during each of the four (4) application events to apply the remediation chemistry in the sandysilt aquifer and smear zone soils. Vacuum extraction was conducted after each PetroCleanze application to recover residual free-phase petroleum hydrocarbons liberated from the soils. Reagent distribution monitoring confirmed PetroCleanze was present across the targeted source area during each application event. Direct-push injection points were advanced using a bottom-up approach between 25 and 20 feet below ground surface (bgs). The injection interval focused on the highest concentrations of contaminants identified in the upper saturated soils and smear zone soils. A total of 13,230 pounds of PetroCleanze were injected via DPT injection points over the course of the project with low pressures and moderate flow rates.
Regenesis Remediation Services™ – PersulfOx® Treats Petroleum Hydrocarbons
In Situ Chemical Oxidation and Enhanced Aerobic Biodegradation Remediate Underground Storage Tank Site
Regenesis Remediation Services (RRS) was contracted to design and implement an in situ chemical oxidation (ISCO) treatment plan to remediate a diesel gas plume from a former leaking underground storage tank (UST) on a residential farm property. The defined treatment area comprised approximately 5,280 square feet (ft2), and the treatment of the gas plume included three application events using
PersulfOx®, with the final application immediately followed by an application with Oxygen Release Compound Advanced (ORC® Advanced). A total of 5,840.6 pounds of PersulfOx and 2,589 pounds of ORC Advanced were injected during the course of the project.
Utilizing PersulfOx remediation chemistry to distribute throughout the subsurface, 91 direct-push injection technology (DPT) injection points were advanced every 100 ft2 over the course of three application events. ORC-A was applied in 53 discrete DPT injection points approximately every 100 ft2. RRS utilized both expendable points and retractable screen-tip injection tooling to apply the PersulfOx and ORC Advanced at discrete intervals across the vertical treatment interval from 8 to 12 feet and 8 to 16 feet below ground surface (bgs) within the sandy saturated soils. Low pressures and moderate application rates were utilized to apply the remediation chemistry at up to four (4) injection point locations simultaneously. RRS personnel performed real-time reagent distribution diagnostics to optimize the distribution of the material.
Former Service Station Treated on Native American Reservation Land
Combined Remedies Used to Remediate BTEX Contamination
Project Highlights
- Enhanced Aerobic Bioremediation and In Situ Chemical Oxidation used to treat high BTEX levels on-site
- Previous remediation activities included soil excavation but contamination persisted
- One application area located in lot used for beef cattle on reservation land and special approvals were required
- Project was state-funded by Pollution Liability Insurance Agency (PILA) of Washington but regulated by Region 10 EPA resulting in extensive coordination between both agencies
Project Summary
This Wapato, Washington site was a former gas station with historical releases dating back to at least 1995. It is located on a Native American Reservation so the site is regulated through Region 10 of the EPA.
The initial remedial activities consisted of excavation of source area soil but contamination remained. Considering the persistent contamination, the goal of the site was to reduce the remaining concentrations to meet regulatory goals.
Remediation Approach
A combied remedies strategy was devised for this site, including in situ treatment in three separate areas. Two areas were treated with both PersulfOx® and ORC® Advanced.
The third area was an empty lot that was used for ranging beef cattle. The client had concerns about how the treatment might affect the cattle, so only ORC Advanced was applied to this area because it is both insoluable and non-toxic. Because the entire site was located on reservation land it required special approvals by the tribal irrigation office before the injections could occur. A total area of 4,100-square-feet was treated for high levels of BTEX. Monitoring is ongoing.
Technology Description
ORC Advanced is a proprietary formulation of food-grade, calcium oxy-hydroxide that produces a controlled-release of molecular oxygen for periods of up to 12 months upon hydration.
PersulfOx is a sodium persulfate-based chemical oxidation technology which destroys both hydrocarbon and chlorinated solvent-type contaminants in the subsurface. PersulfOx contains a built-in catalyst which activates the persulfate component and generates contaminant-destroying free radicals without the need for the addition of a separate activator
PersulfOx® ISCO Remediation Reduces BTEX F1 & F2 Concentrations at Alberta Municipal Affairs Site
ISCO Solution Results in Cost Savings and Treatment Area Reduction at Former Service Station
Project Highlights
- In Situ Chemical Oxidation (ISCO) used as a cost-effective alternative to excavation remediation methods
- In Situ treatment using direct push resulted in reduction in treatment area
- ISCO solution met time and budget goals
Project Summary
BTEX contaminated soil was found at an Alberta Municipal Affairs (AMA) site. The former service station located in Central Alberta, Canada had left a petroleum leak creating a smear zone with F1 and F2 concentrations at the source of the plume. Since the AMA site had limited funding and time constraints, a persulfate-based ISCO solution using PersulfOx was recommended to significantly reduce high petroleum concentrations in the soil and groundwater. This site marked the first time the engineering firm working with REGENESIS had employed an ISCO solution, having used excavation remediation methods as their recommended approach in the past. An expedited remediation plan was created and included multiple rounds of PersulfOx injections to treat the site.
Remediation Approach
PersulfOx was applied in seven existing monitoring wells. Working with the engineering firm, using direct-push injection of PersulfOx, REGENESIS strategically focused the application around two of the existing monitoring wells. Due to the saturated soil type and an increased risk for surfacing, precise application-volume monitoring was required. After the first round of two applications was completed, overall contaminant concentrations decreased.
REGENESIS Solution Applied
PersulfOx is a sodium persulfate-based chemical oxidation technology which destroys both hydrocarbon and chlorinated solvent-type contaminants in the subsurface. PersulfOx contains a built-in catalyst which activates the persulfate component and generates contaminant-destroying free radicals without the need for the addition of a separate activator.
Results
The REGENESIS ISCO plan incorporating direct-push injections of PersulOx significantly reduced the level of BTEX contaminant concentrations following the first round of application. The PersulfOx solution effectively addressed the plume in the saturated smear zone, while meeting the goals of the project, as well as the client’s time and budget constraints.
Former Paint Manufacturing Facility Treated for MIBK, BTEX
RRS Implements Cost-Effective, Turn-Key Remediation in Low-Permeability Soils
Project Highlights
- Soil and groundwater impacted with both BTEX and MIBK.
- Low-permeability soil was of a concern to the client, however very little surfacing was witnessed post-injection.
- Regenesis Remediation Services (RRS) finished the project in half the time and nearly half the cost of competing firms.
Project Summary
Site operations at a former paint manufacturing facility in Northern California caused soil and groundwater to be impacted with MIBK and BTEX compounds. The site was under an order for clean-up through the regional water quality board and the treatment was designed to use in situ chemical oxidation (ISCO) to reduce contaminant mass in the source area before transitioning to MNA.
Remediation Approach
Comprised of what the consultant described as “San Francisco Bay Muds” or essentially clay soil with sand stringers, the site had challenging geologic conditions. At first, the client was apprehensive about the ability to inject PersulfOx® into the tight soils without surfacing. However, a turn-key approach was devised during the design of this project, with an emphasis on minimizing product application costs and addressing any possible surfacing issues. A total of 29,644 pounds of PersulfOx was applied by RRS in two applications, through a total of 58 directpush points and 2 injection wells at the site. The product was applied at a 20% solution for a total injection volume of 15,691 gallons.
The injections were completed in half the time and nearly half the cost of what other injection contractor firms proposed. The capabilities of the RRS team, trailer and ability to manifold and inject into four points at one time resulted in significant time and cost savings for the client. Monitoring is ongoing.
Technology Description
PersulfOx is a sodium persulfate-based chemical oxidation technology which destroys both hydrocarbon and chlorinated solventtype contaminants in the subsurface. PersulfOx contains a built-in catalyst which activates the persulfate component and generates contaminant-destroying free radicals without the need for the addition of a separate activator.
RRS is a dedicated team of scientists and engineers whose primary function is to provide environmental engineering and consulting firms with specialized groundwater and soil remediation planning, design, verification and application services.
