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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
In Situ Chemical Oxidation Treats High TPH Concentrations
Over 114,000 Pounds of PersulfOx® Applied to Illinois Manufacturing Facility
Project Highlights
- High levels of TPH and TCE were detected on-site after a suspected cutting oil/degreasing solvent spill.
- Remediation mandated after oil sheen observed in river adjacent to manufacturing facility.
- In Situ chemical oxidation (ISCO) paired with excavation to remediate site.
- Tight treatment deadline met through the use of PersulfOx in 2,204-pound SuperSacks, which were delivered within a few days’ notice.
Project Summary
An Illinois metal fabrication manufacturing facility has been in operation since the early 1900s and is still active today. The use of cutting oils and degreasing solvents lead to high levels of TPH and TCE on-site. The state of Illinois cited the facility for a violation when an oil sheen was observed seeping from the property into an adjacent waterbody. A mechanical oil recovery system was installed and absorbent booms were used to mitigate the oil from reaching the river. ISCO was selected as the remediation approach to address the contamination below the active facility through a series of applications. Additionally, the TCE area was treated with PersulfOx® via injection wells and a soil mixing application.
Remediation Approach
Prior to the start of remediation activities, the primary consultant was removed from the project and a new firm was brought in. The remediation firm placed a tight deadline (a couple of months) to complete the full scope of activities. REGENESIS was able to assist with keeping the project on-deadline through the delivery of 2,204-pound PersulfOx SuperSacks, which were delivered within a few days’ notice. The consultant had a series of injection wells installed inside and outside of the building. PersulfOx was injected into these wells during three applications over a three-month period. Additionally, the TCE area was treated with PersulfOx through a soil mixing application using an excavator. The final step of the remediation plan is to treat the TPH-impacted soils outside the building through excavation, and Oxygen Release Compound (ORC®) Advanced Pellets will be used as a long-term oxygen source for enhanced bioremediation of the residual TPH.
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.
ORC Advanced Pellets are a pelletized version of REGENESIS’ widely used ORC Advanced and are designed specifically for direct application into excavations, tank pits and trenches. This pelletized, dry application material minimizes airborne dust while eliminating the need for specialized equipment and spray water required for powder-slurry applications.
Site Closure Achieved at Colorado Service Station
Benzene Levels Reduced to Below 5 PPB in Clay Soils through Use of ORC® Advanced
Project Highlights
- Benzene concentrations remained on-site despite previous excavation efforts.
- Enhanced aerobic biodegradation using ORC Advanced produced a 99.8% reduction over 12 months.
- Benzene reduced to below detection limits.
- “No Further Action” letter granted in October 2010.
Project Summary
Three underground storage tanks (USTs) were removed at a former tire store as part of corrective measures. Roughly 108 cubic yards of soils were excavated to reduce contamination levels. However, the excavation did not extend below the groundwater interface and residual sorbed contaminant mass remained, resulting in a lingering benzene plume. The client was interested in an in situ approach to reduce the remaining benzene contamination to below the Tier 1 risk based screening level of 5 ppb.
Remediation Approach
A direct-push injection of Oxygen Release Compound Advanced (ORC® Advanced) was chosen to reduce remaining soil and groundwater contamination at the location of the former excavation and well BW-1. Maximum TVPH and benzene concentrations in the prior two years were as high as 2.4 mg/L and 0.48 mg/L, respectively. Due to tighter soils, a 7-footon-center grid pattern with 15 injection points was implemented on-site. ORC Advanced was injected from approximately 6 to 13 feet below ground surface with about 1 foot of the injection interval extending above groundwater in the event of rising water levels. A total of 725 pounds of ORC Advanced was injected for this project.
Despite the relatively tight soils and high potential for contaminant back diffusion, the ORC Advanced treatment resulted in consistent downward trends of benzene contamination. A 96.3% reduction in benzene after only 3 months was observed. By month 12, a 99.8% reduction to below detection limits (The site was granted a no further action letter.)
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.
REGENESIS Remediation Services – LNAPL Treated with Combined Remedies
Active Michigan Service Stated Remediated Through Use of PetroCleanze® and ORC® Advanced
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. PetroCleanze® was chosen as the primary remediation technology to facilitate recovery of residual LNAPL and chemically oxidize contaminants without negatively impacting sensitive infrastructure. ORC® Advanced was also applied with the final PetroCleanze application event and in a downgradient plume cut off barrier to promote the enhanced aerobic bioremediation of the dissolved-phase petroleum hydrocarbons.
Eight injection/extraction wells and 28 direct-push injection points were used to apply the remediation reagents in the silty sand aquifer and smear zone over three application/injection events. Vacuum extraction was conducted between PetroCleanze applications to recover residual free phase petroleum hydrocarbons liberated from the soils. Reagent distribution monitoring confirmed PetroCleanze was dispersed across the targeted source area during each application event.
Prior to the first PetroCleanze application event, no measurable free product was observed on this site since 2006. Less than twenty-four hours after the first PetroCleanze application event, LNAPL was observed in four of the eight wells in the source area at quantities up to three inches thick.
Not more than a sheen was observed in any wells on site after the third injection event. A total of 2,160 pounds of PetroCleanze and 1,120 pounds of ORC Advanced were injected.
Regenesis Remediation Services™ – LNAPL Plume Treated at Iowa Service Station
PetroCleanze and ORC Advanced Remediate Historic Petroleum Hydrocarbon Contamination
RRS was contracted to remediate a dissolved phase LNAPL petroleum hydrocarbon plume petroleum fuel releases at a former service station PetroCleanze® was chosen as the primary remediation technology to facilitate recovery of residual LNAPL and chemically oxidize contaminants without negatively impacting sensitive infrastructure. ORC Advanced was also applied with the final PetroCleanze application enhanced aerobic bioremediation of hydrocarbons.
Eighteen direct-push injection points were used to apply the reagents in the silty sand aquifer and application events. Three vacuum extraction conducted after each PetroCleanze application to recover residual free phase petroleum hydrocarbons liberated from the soils.
Reagent distribution monitoring confirmed PetroCleanze was dispersed across the targeted source area during events.
Direct-push injection points were advanced to 15 feet below ground surface where bottom-up injections were performed to 5 feet. A total of 4,470 pounds of PetroCleanze and 720 pounds were injected.
ORC Advanced® Treats Multiple Plumes and High TPH Concentrations
CASE SUMMARY
Past operations at a former U.S. Navy Base in American Samoa had resulted in total petroleum hydrocarbon (TPH) contamination within the subsurface. Currently occupied by an elementary school, the former military base once stored barrels of petroleum-based fuels for military operations. A hydrocarbon sheen was evident following rain events prompting the need for a remedial investigation to determine the extent of contamination within the subsurface. Soil boring samples revealed elevated levels of TPH-diesel, TPH-gasoline, and TPH-motor oil at concentrations exceeding the cleanup standard. Site investigations did not identify any TPH impact to groundwater.
Access to the site and equipment was very limited thus on-site sampling and remediation was conducted only annually when the school was out of session. As a result, a remedial approach was required in which no operations & maintenance would be necessary. In addition, a technology was needed which would not damage on-site structures, successfully treat low permeable soils, and not disrupt the day to day operations of the elementary school. Enhanced bioremediation using ORC Advanced® was chosen since it did not require on-site maintenance and would effectively treat TPH concentrations within a reasonable timeframe.
REMEDIATION APPROACH
The initial application of ORC Advanced® was applied in 2005 via multiple trenches to address the three identified plumes (Figure 4). ORC Advanced® was mixed with water to form a slurry then placed at the bottom of each trench prior to backfilling (Figure 3). Soil sampling one year later indicated a reduction in TPH levels; however three boring samples remained above the cleanup goal. This was explained by the lack of water available in the subsurface to move the ORC Advanced® radially from the applied trench area. A second application in 2006 was delivered via direct-push injection using approximately 2,000 pounds of ORC Advanced® into a total of 82 injection points (Figure 5 & 6). In 2007, an ORC Advanced® injection application was completed to treat the few remaining hot spots. One last application is scheduled for summer 2008.
RESULTS
Trench Application
The 2005 trench application was successful in reducing TPH concentrations significantly (Table 1). Within the area of highest concentrations (PMA-05), TPH-diesel was reduced from 2,800 milligrams per kilogram (mg/kg) to 1,700 mg/kg, TPH-motor oil declined by 50% and TPH-gasoline was reduced to below the cleanup goal of 50 mg/kg. Of the eight sampled areas, three remained above the Project Action Level – PMA-01, PMA-02, and PMA-05. Although the trench application was successful in reducing concentrations within the immediate application area, the radius of influence was not great enough to remediate the entire plume. Therefore, a follow up application was designed using direct-push technology.
Direct-Push Application
The direct-push application substantially reduced high concentrations of TPH-diesel and TPH-motor oil (Table 2). Most significant was area PMA-05 where TPH-diesel declined from 1,700 mg/kg to below the cleanup goal and TPH-motor oil was reduced from 4,100 to 120 mg/kg, a 97% reduction. An increase in concentrations was observed as a result of the direct-push technique which mobilized residual contamination from the soil. A direct-push injection was completed in July 2007 to address the remaining concentrations of TPH-diesel and TPH-motor oil. A total of 2,500 pounds of ORC Advanced® were applied using the same design layout as the 2006 application (Figure 5). One last application is planned for summer 2008.
CONCLUSION
To date, one ORC Advanced® trench application and two direct-push injections have been completed. The trench technique was effective within the immediate vicinity of the application. However, in order to achieve a better radius of influence, the direct-push technique was more effective. Additionally, the impact and inconvenience to the site from direct-push was significantly less in comparison to the large trenched areas as shown in Figures 2 and 3.
TPH-motor oil has remained above the cleanup goal as seen in Table 2. This can be explained by the fact that the molecular size of motor oil is more significant compared to diesel and gasoline and, therefore, more time is needed to breakdown the molecule. In addition, as a result of the injection, mobilization of residual contamination from the soil caused an increase in concentrations. The July 2007 application is expected to continue the breakdown of any remaining contamination, including motor oil, towards the cleanup goal. Sampling will again be completed in the summer of 2008 along with one final ORC Advanced® application.
Site Closure via In Situ Aerobic Bioremediation of Petroleum Hydrocarbons
Summary
A former fueling facility in Port Coquitlam, BC contained four USTs and accompanying dispensers. The USTs were removed in 1990 after volatile petroleum hydrocarbon (VPH) concentrations were found above regulatory limits. Well BH206 had significant VPH and naphthalene concentrations reaching 13,000 μg/L and 240 μg/L, respectively. In addition, wells BH 303 and BH 205A had concentrations of VPH as high as 5,600 μg/L.
Remediation Approach
Excavation activities removed approximately 1,300 m3 of contaminated soil which were later disposed of at a permitted facility. Following the excavation, a groundwater remediation program was implemented using 1,350 lbs of Oxygen Release Compound (ORC®). An ORC slurry was added to the backfill and injected into the groundwater plume to further reduce VPH concentrations as well as light extractable petroleum hydrocarbons (LEPH). A second application using 500 lbs of ORC Advanced® was applied one year after the ORC application to continue reducing trends of petroleum hydrocarbons.
VPH Time Lapse Shots
Results
As shown in the VPH time lapse shots on the front, VPH reduction occurred across the plume. Approximately, one year after injection VPH declined from 13,000 μg/L to 4,300 μg/L in well BH206 and well BH303 showed a decrease of 80%. Downgradient of the source area VPH was reduced below cleanup goals. Prior to injection, a total of 7 wells had LEPH concentrations above the standard (500 μg/L). By day 510, four wells reached concentrations below cleanup goals. Reduction of naphthalene was also seen across the contaminated area (Table 2). Most notable are the 3 wells that reached the cleanup standard 510 days after injection.
Within 3 years of the initial application, all contaminants of concern were reduced to below the cleanup goals. Concentrations of VPH and LEPH were reduced by 1 to 2 orders of magnitude and naphthalene declined from a high of 280 μg/L to 7.9 μg/L. The site achieved closure approximately 5 years after commencing remedial treatment.
Combined RegenOxTM and ORC Advanced® Application Treats TPH and BTEX
Introduction
Operations at a former car dealership resulted in petroleum hydrocarbon contaminated soil and groundwater. In the source well SB7, groundwater concentrations of total petroleum hydrocarbons (TPH) had increased to 250 parts per million (ppm) and concentrations of benzene, toluene, ethylbenzene, and xylenes (BTEX) were present at more than 400 ppm. In order to reach the TPH site specific target level (SSTL) of 19.2 ppm, a combined remedial approach using chemical oxidation and enhanced aerobic bioremediation was implemented. Injections of RegenOxTM and ORC Advanced® were applied in four separate injection events (Table 1). The combined approach was designed to treat the high concentrations and promote aerobic bioremediation of any remaining residual contamination.
Remediation Approach
The remedial objective was to reduce high concentrations of TPH to below the SSTL of 19.2 ppm. RegenOx was applied in April 2006 and June 2006 across the plume (Figure 1). Both RegenOx and ORC Advanced were applied separately in July 2006 and September 2006. (Table 1)
In Situ Treatment Results
Shortly after the initial RegenOx chemical oxidation treatment, TPH was reduced by an average of 67% (Graph 1). As is typical following the first chemical oxidation application, contaminant rebound occurred after approximately one month. This is primarily a result of rapid desorption of sorbed phase contaminants from soil into groundwater and the 30 day longevity of RegenOx. Three follow up RegenOx injections were applied to continue treatment and eliminate the remaining contamination. Additionally, two ORC Advanced injections were performed to provide a long-term (12 months on average) oxygen source for enhanced aerobic bioremediation.
RegenOx was effective at reducing TPH to below the SSTL in all wells, excluding SB7 (Graph 1) which was located within the source area. However, a reduction of 95% occurred in SB7 within two weeks of the initial RegenOx injection. Rebound was observed in this area throughout the treatment, indicating that sorbed phase TPH was more prevalent around this well. RegenOx reduced the overall TPH loading of the soils and maintained TPH concentrations in groundwater to below 60 ppm. The ORC Advanced applications are expected to further TPH reduction in this area via enhanced aerobic biostimulation beyond the length of the monitoring program.
Conclusion
As a result of the RegenOx applications, concentrations were reduced quickly and cost-effectively within weeks of the injections. It is expected that the remaining concentrations above the SSTL in Graph 1 will be reduced as ORC Advanced continues to release oxygen. Successful closure was achieved due to the overall reduction in TPH concentrations, the observed reduction in contaminant concentrations in the source area, and the expected future reductions from the application of ORC Advanced.
Rapid Reduction of Petroleum Hydrocarbons using ORC Advanced® allows for Redevelopment of Site
Summary
Remedial works at the Former Lama Petroleum site were undertaken in late 2008 as part of the ongoing redevelopment of the Fresh Wharf Estate in Barking UK. The site was to be developed for light industrial use, however, historical oil mixing handling and storage activities performed on the site had resulted in TPH and PAH contamination in the groundwater.
Site investigation works suggested the presence of an approximately 1,000m2 source area in thenorthwestern portion of the site, as well as a downgradient plume area, estimated to be in the region of 6,000m2 extending towards the Handtrough Creek. Phase separated hydrocarbons were detected in the source area where the former above ground storage tanks had been located prior to decommissioning circa 2003. In the downgradient plume area, the maximum dissolved phase TPH concentration was 1,100μg/L (Monitoring Well BH102) and located adjacent to Handtrough Creek.
Remedial Strategy
The remedial objective was to reduce dissolved phase concentrations of Total TPH and PAH in groundwater to the agreed remedial target level of 110μg/L, within 12 months of treatment. A trigger level for further remediation was set at 200μg/L, equating to an 80% contaminant concentration reduction within 42 weeks post treatment. If the trigger TPH concentration was not achieved within 42 weeks after treatment, further options would be undertaken.
The original assessment of remedial options identified that a combination of Pump and Treat (P&T) to target free product in the source area and ORC Advanced® treatment in the groundwater plume would represent the most time‐efficient and cost‐effective remedial solution for the site. However, trial pits advanced in the source area during site clearance works
determined that free product was not present in the groundwater, but was present in discrete bands within the unsaturated made ground. Following this observation, excavation to remove the most impacted soils in the source area was determined to be the most suitable approach and P&T was discarded as an option.
Soil removal works were undertaken at the site in October 2008. ORC Advanced treatment in both the source and plume areas was undertaken in October and November 2008. ORC Advanced was applied using three direct push injection rigs and a separate mixing and pumping unit. The rods were driven to 6mBGL and the ORC Advanced was applied over the impacted saturated zone as the rods were slowly withdrawn to 3mBGL. The application included a total of 813 injection points over 19 drilling days. The dose rates were varied to match the different contaminant concentrations and conditions encountered across the site (Tables 1 & 2). Vibro‐piling works were completed across the site at the same time as the ORC Advanced was being applied and were unimpeded by the direct push equipment.
Results
Following the injection of ORC Advanced, a slight increase in the dissolved phase contaminant concentrations was observed due to the site disturbance from injection and piling works. Both TPH and PAH concentrations then rapidly decreased to below the site specific remedial target values and remained low over the monitoring programme. A 99% reduction in the groundwater concentrations of TPH and PAH was achieved with no rebound. Monitoring results are presented below for well BH102, which was located on the southern site boundary, adjacent to Handtrough Creek.
Conclusion
Following the application of ORC Advanced, TPH and PAH concentrations were rapidly reduced and maintained below the site specific target values without contaminant rebound. The works were completed safely and efficiently and did not hinder the ongoing construction works occurring simultaneously at the site. The low final contaminant concentrations and the lack of rebound resulted in regulatory acceptance of the remediation and development works were completed.
London Olympic Park Environmental Cleanup Uses Bioremediation Technology ORC Advanced® to Treat Hydrocarbons and Expedite Construction
The multi-billion dollar development of the 500 acre London 2012 Olympic Games Park has been one of the largest Brownfields regeneration projects in recent years. Located in Stratford in East London, the site was formerly an industrial estate with uses including: chemical, fertilizer, engineering works, landfills and depots leaving a legacy of soil and groundwater contamination.
The Olympic Delivery Authority (ODA) set strict deadlines for the Olympic facility construction projects. The development included the construction and refurbishment of 16 new major stadia and sports facilities. More specifically, the subsurface foundations for the London Aquatic Centre (LAC) were to be completed by the 27th July 2009 (exactly three years before the London 2012 Olympic Games Opening Ceremony).
The LAC site was contaminated with petroleum hydrocarbons from lubricating oil as a result of historic operations. The first stage of remediation began in November 2007 using dual-phase vacuum extraction (DPVE) to remove the LNAPL, however due to the strict ODA deadlines and integration with construction programmes (starting in April 2008) prolonged use of DPVE was not practical to remediate the dissolved phase hydrocarbon plume. An in situ
solution became the only viable option.
In Situ Enhanced Bioremediation, a widely accepted and well understood natural biodegradation process was chosen to cleanup this portion of the site. This approach
utilizes indigenous microbes to aerobically biodegrade petroleum hydrocarbons in-place. The actual process is facilitated using an injectable, Advanced Oxygen Release Compound (ORC Advanced®). Upon hydration and injection, this powder-like material accelerates aerobic bioremediation by releasing molecular dissolved oxygen for periods up to 12 months on a single application. Without this valuable oxygen supply, the required aerobic bioremediation processes either cease or proceed at very slow rates
The patented Controlled-Release Technology (CRTTM) in ORC Advanced allows for an efficient, long-term release of oxygen which provides optimal conditions for sustained aerobic biodegradation. CRT also saves time and money during implementation by eliminating the need for multiple oxygen release compound applications.
Additionally, ORC Advanced® was applied at the LAC site using direct-push injection. This application approach is highly efficient as it requires no permanent well installation, above-ground piping or mechanical equipment and after application, no operational costs or further site disturbance. Remedial objectives or the Olympic Games Aquatic Centre were satisfied and redevelopment of the site was unhindered by the ongoing in situ remedial work. More importantly, the construction-phase was completed according to the ODA set deadlines.
REGENESIS is proud to have supported environmental consultants, remediation contractors and regulators in successfully delivering the multi-billion dollar, award winning, remediation for The London 2012 Olympic Games.
