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Remediation of a Former Builder’s Yard, Bedfordshire, UK
Case study on the cost-effective treatment of TPH and PAH at a brownfield site in the UK. Read More
ORC Advanced® and PersulfOx® Application Reduces BTEX, TPHg, and TPHd at an Active Service Station in Las Vegas
Significant cost savings to client achieved using enhanced aerobic biodegration and In Situ Chemical Oxidation (ISCO)Read More
Contaminant Concentrations at an Active Gas Station Reduced by 90% Using PersulfOx® and ORC Advanced®
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
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.
State-Funded Cleanup of Former Service Station on Reservation Land
Enhanced Aerobic Biodegradation and In Situ Chemical Oxidation Provides Safe Approach to Remediate TPH-g and BTEX
Project Highlights
- Extensive coordination was required between state-funded Pollution Liability Insurance Agency (PILA) of Washington and US EPA Region 10
- Combined remedy approach using ORC Advanced® and PersulfOx® provided a safe solution for land used to raise livestock
Project Summary
The site located in Wapato, Washington is a former gas station situated on Reservation Land with historical releases dating back >20 years. The site is regulated through US EPA Region 10 and was previously an empty lot used for ranging cattle.
Initial remedial activities included excavation of source-area soil, however persistent contamination remained. Concerns were raised regarding how amendments might affect livestock. As a result, the remediation approach needed to be environmentally benign. The revised remedial plan included Enhanced Aerobic Biodegradation (ORC Advanced) and In Situ Chemical Oxidation (PersulfOx) to reduce the remaining concentrations and meet regulatory goals.
Technology Description
PersulfOx is a chemical oxidant that rapidly reduces the mass of the contaminants. This chemical consists of 90% sodium persulfate and 10% catalyst powder. PersulfOx is very effective in rapid oxidation of petroleum hydrocarbons in both soil and groundwater.
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
An integrated treatment strategy was devised, which included injections in three separate areas. Two areas were treated with PersulfOx and ORC Advanced. The third area was treated with ORC Advanced only.
The by-products of ORC Advanced and PersulfOx are both insoluble and non-toxic, making the application safe and effective. Consequently, there were no issues relating to the landowner’s concern for amendments affecting livestock. A total area of 4,100 ft2 was treated for high levels of BTEX and TPH-g. Monitoring is ongoing.
LNAPL Remediation in a Chalk Aquifer under a Residential Property
with BRD Environmental Ltd
Introduction
After completion of the redevelopment of former industrial land into residential properties, significant Total Petroleum Hydrocarbon (TPH) contamination was discovered in the groundwater and smear zone under the gardens and parking area. The TPH comprised diesel and heating oil, with up to 40mm of Light Non- Aqueous Phase Liquid (LNAPL) evident in the monitoring wells.
The original source of contamination (an above-ground storage tank) was removed during redevelopment; however, residual contamination had migrated into a lower chalk aquifer and after the discovery of LNAPL present within chalk fissures above the water table, remedial action was required.
Figure. 1 On site RegenOx® injections using a direct push injection rig
Figure. 2 Total TPH Concentration in Boreholes BH13 and BH14
Method
The two most highly contaminated boreholes, BH13 and BH14, were located in a back garden and a car parking space. As space was restricted and to minimise the impact of works on residents, an in situ remedial technique was deemed the only viable option.
RegenOx® is an In Situ Chemical Oxidation (ISCO) reagent capable of treating high concentrations of a broad range of soil and groundwater contaminants including both petroleum hydrocarbons and chlorinated solvents.
The alkaline nature of RegenOx enabled its use within the chalk aquifer without adverse matrix reaction.
The ability of RegenOx to deal with both LNAPL and dissolved phase contamination avoided the use of ‘pump and treat’ equipment onsite. This minimised both operational and disposal costs and negated the requirement for bulky equipment on the site. Applications were completed using a small direct- push injection rig (Figure 1). This meant that the resident’s parking area could be reinstated at the end of each working day, so that they could park overnight as usual.
The RegenOx injections were completed in three events at two week intervals during June and July.
Results
A 99% reduction of TPH concentrations occurred rapidly in boreholes BH13 and BH14 following the injection works, with LNAPL no longer observed on the site.
Conclusion
A short campaign of RegenOx applications at the site completely removed any LNAPL and reduced TPH concentrations by 99% in a chalk aquifer and regulatory closure was achieved within a short period.
At £55,000 for the product and application work, the project was extremely cost effective, avoiding the use of operational and disposal costs on the site. The in situ nature of the works avoided disturbing or inconveniencing residents living on the site.
ISCO and Bioremediation at Former Petrol Station, Pays de la Loire, France
Under a former petrol filling station in the Loire Valley, in France the soil and groundwater was found to be contaminated with petroleum hydrocarbons (primarily BTEX). An integrated in-situ remedial solution has been put in place by a specialist remediation contractor, consisting of 26 PersulfOx injections in the source zone for fast and effective treatment of the most impacted soils and groundwater. ORC Advanced was also applied in the source zone to achieve long term in-situ bioremediation of any remaining petroleum hydrocarbons. In addition, an ORC Advanced barrier has been installed in the downstream plume area, to prevent off-site migration of the contamination.Read More
ISCO and Enhanced Aerobic Bioremediation during Residential Development
Excavation works minimised through the use of RegenOx, ORC-Advanced and ORC-Advanced Pellets, allowing development to continue without interruption.Read More
Chlorinated Solvent Remediation via ISCO at Former Industrial Site in Barcelona, Spain
Due to the target area extending under the footprint of the proposed building and the short build programme, a grid of horizontal injection pipes was installed in the subsurface prior to construction commencing. The grid was then linked to a remote injection location, so that when the new building was constructed, injection was simultaneously completed underneath it. The intention of the remediation was to achieve a rapid and significant reduction of the contaminant concentrations in the groundwater. PersulfOx was selected as the preferred ISCO agent due to its efficiency and capability of moving through the vadose zone into the groundwater, guaranteeing a good distribution.Read More
Pilot Test of ISCO Soils Treatment in Industrial Area, Italy
At a former oil refinery in Italy, leaks from several large Aboveground Storage Tanks (ASTs) had caused the soil to become impacted with fuel. Concentrations of up to 3,000 mg/kg of petroleum hydrocarbons were measured in the unsaturated soil within the immediate vicinity of the ASTs. Read More
Innovative Application of PersulfOx Addresses BTEX Contamination at Former Gas Station Site
Project Highlights
- Innovative remediation plan designed by IRSL to address hydrocarbon plume using PersulfOx® addresses migrating plume
- Cleanup criteria on site was reached with only two injections of PersulfOx
- Direct Push Technology using PersulfOx counters any back diffusion
Project Summary
An active gasoline station in southwestern Ontario exhibited a hydrocarbon plume, which was migrating off site toward commercial buildings, presenting liability concerns for developers. Previous remediation efforts using other oxidants, including base-activated persulphate, did not result in significant reductions, and rebound was a problem, including pH buffering. InSitu Remediation Services, Ltd. (IRSL) was the consulting firm hired to perform the remediation work.
Led by Rick McGregor, IRSL designed an approach that included REGENESIS’® PerfulfOx to address the concentrations in the plume including BTEX ~ 25 mg/L, F1 ~29 mg/L, and F2 ~ 1.5 mg/L. The geology was silty sand with sand lens and a unconfined aquifer. The client’s cleanup goals were F1 0.75 mg/L and F2 0.15 mg/L. Two injections of PersulfOx using Direct Push Technology (DPT) were applied, targeting the sand lens and providing enough mass to allow for diffusion of PersulfOx into the silty sand to counter back diffusion.
Technology Description
PersulfOX and PersulfOX SP promote the rapid and sustained in situ oxidation of a wide-range of organic contaminants. As an advanced in situ chemical oxidation (ISCO) reagent, it destroys organic contaminants found in groundwater and soil through abiotic chemical oxidation reactions.
This turn-key, all-in-one product with a built-in catalyst 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.
With the purchase and proper use of PersulfOx Catalyzed Persulfate, clients gain the benefits of the latest advancements in persulfate technology for environmental remediation. PersulfOx SP was formulated for use on projects specifying the use of persulfate and a separate chemical activation process such as alkaline activation, hydrogen peroxide activation, or iron activation. It can also be used as a follow-on treatment to REGENESIS’ PersulfOx Catalyzed Persulfate technology.
Results
Following the two injections of PersulfOx using direct push technology, cleanup criteria was reached quickly, resulting in two-plus years of sublevel monitoring.
About InSitu Remediation Services
One of Canada’s most experienced remediation companies, InSitu Remediation Services Ltd. (IRSL) has designed, implemented, and maintained soil and groundwater remediation programs in diverse geological environments in North, Central, and South America, Europe and the Middle East. The company offers remediation support services and specializes in ensuring the most efficient use of technical and financial resources, managing shortened remedial time-frames, and mitigating unnecessary technical and financial risk.
Rick McGregor, B.Sc. Geology, M.Sc. Hydrogeology, M.B.A., is president of InSitu Remediation Services Ltd. A respected environmental professional with over a quarter century in environmental assessment and remediation, he has designed and implemented remediation programs across the globe.
