PetroFix and ORC Advanced Excavation

Estimated Reading Time: < 1 minute

Case study highlights:

  • Success at this site can shape and improve the treatment of other similar sites
  • PetroFix technology allowed Antea Group to design a remediation strategy that was fast, affordable, and highly effective

This case study reviews a former gas station site where Antea Group developed an excavation plan involving PetroFix™ and ORC Advanced® pellets to address contaminant levels following the excavation and removal of contaminated soil. This marks the first site where the remediation plan employs applying a mixture of both PetroFix and ORC Advanced pellets at the base of the excavation along with spray-applying PetroFix to the sides of an excavation pit. Antea Group was tasked with the remediation of the site. Working with the REGENESIS team, Antea Group specified the application of PetroFix in conjunction with the excavation due to the product’s ability to sorb and biodegrade petroleum hydrocarbons. The remediation design called for mixing PetroFix and ORC Advanced pellets into the base of the excavation site and applying PetroFix to the sides of the excavation pit.

In Situ pilot remediation of gasworks impacted groundwater, Stockholm, Sweden

Estimated Reading Time: 3 minutes

Introduction

In the north-east of Central Stockholm, a historical industrial site was earmarked for redevelopment. Part of the site comprised a former gasworks, where historical operations have caused a complex mix of contaminants to impact the surrounding soil, groundwater and shoreline sediments.

The large site is due to be redeveloped in a series of parcels including a road, industrial park, residential homes and schools. Remediation is required to ensure the human health risk is removed as part of the restoration of the site. The impacted groundwater also represents an environmental risk and requires treatment. Risk assessments were used to determine that remediation was required to a depth of 20m BGL. The geology of the site is heterogeneous, comprising a shallow made ground, a clay layer and underlying coarse sands.

The sands are highly impacted with a range of gas works contamination included creosote NAPLs and high levels of benzene. The saturated clays are also impacted with dissolved phase contamination. Due to contaminants, concentrations and superficial geologies, a range of remedial methods would be required to ensure the most appropriate was used in each scenario. Therefore, RGS Nordic engaged REGENESIS to design a series of pilot tests utilising several in-situ methods. The results from these trials would then be used to shape the full-scale remediation strategy for the entire gasworks site area.

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Combined In Situ Remediation Approach and Planning

REGENESIS proposed a pilot-scale combined remediation approach comprising:

  • Enhanced desorption using PetroCleanze to target high concentrations of soil-bound contaminants of concern (COC’s) in the sands,
  • In Situ Chemical Oxidation (ISCO) using both RegenOx and PersulfOx to target medium to high dissolved phase and soil-bound PAHs in the sandy soil, and
  • Enhanced aerobic degradation using ORC-Advanced to target the low dissolved phase benzene and naphthalene concentrations in the clay.

Results

Groundwater samples were collected 3-4 months after the application of REGENESIS remediation products, see graphs 1 to 3. The results are displayed below

Enhanced Desorption using PetroCleanze

>95% reduction in dissolved phase benzene was achieved with the addition of PetroCleanze. The treatment for PAHs was found to be less effective, primarily due to the low baseline PAH concentrations which were below the optimum treatment concentration range for PetroCleanze.

Graph 1– Effect of PetroCleanze application on dissolved Benzene concentrations

ISCO using RegenOx and PersulfOx

>90% reduction in dissolved phase benzene and PAHs was observed using PersulfOx. In the RegenOx trial, dissolved benzene concentrations were found to decrease by 80%, while PAH levels increased slightly, potentially due to large volumes of desorbed COCs being released into groundwater post-treatment.

Enhanced Aerobic Biodegradation using ORC-Advanced

A sustained reduction in Naphthalene and benzene (despite suspected influx into the test area) was achieved using ORC-Advanced in the saturated clay.

Graph 2– Effect of PersulfOx application on PAH concentrations

Conclusion

  • A wide range of contaminant concentrations were treated effectively using a combined in-situ remediation approach.
  • Substantial reductions in COC concentrations were achieved despite the challenging geological setting.
  • The results from the pilot tests show that all areas of the gasworks site can be successfully remediated in-situ using REGENESIS remediation products, providing significant cost savings when compared with conventional techniques

Graph 3– Effect of ORC-A application on PAH concentrations

PlumeStop® and ORC Advanced® Applications Achieve Successful Results in 24 Hours

Estimated Reading Time: 5 minutes

Project Highlights

  • Successful rapid reduction of petroleum hydrocarbon contaminant concentrations in soil and groundwater completed within approximately 24 hours.
  • In Situ injection application of PlumeStop® Liquid Activated Carbon and ORC Advanced technologies assist REGENESIS strategic partner in bringing closure to facility identified as Leaking Underground Storage Tank (LUST) site
  • Petroleum hydrocarbon concentrations (PHCs) in groundwater and soil reduced below Washington Department of Ecology’s (Ecology) Model Toxics Control Act (MTCA)

Project Summary

An active gasoline station in Bothell, Washington was listed as a hazardous Leaking Underground Storage Tank (LUST) site by the State of Washington Department of Ecology (Ecology) after two subsurface investigations detected petroleum hydrocarbon-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 Model Toxics Control Act (MTCA), despite 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 using PlumeStop and ORC Advanced technologies.

Technology Applied

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 expediting permanent contaminant biodegradation.

ORC Advanced (ORC-A) – an engineered, oxygen-release compound designed specifically for enhanced, in situ aerobic bioremediation of petroleum hydrocarbons in groundwater and saturated soils that, upon contact with groundwater, produces a controlled-release of molecular oxygen (17% by weight) for periods of up to 12 months in a single application, accelerating aerobic biodegradation processes up to 100 times faster than natural degradation rates.

Background

Despite the installation of three groundwater monitoring wells (MW-1 through MW-3) in 2002 and five additional monitoring wells (MW-4 through MW-8) in 2003, concentrations of total petroleum hydrocarbons in TPH-g and BTEX in the western portion of the site exceeded the Model Toxics Control Act (MTCA) Method A cleanup levels. In 2004, a soil vapor extraction (SVE) system and an air-sparge (AS) system were installed and by 2005 an estimated 2,076 pounds of total volatile hydrocarbons (TVH) were extracted, with concentrations falling below MTCA Method A cleanup levels for two consecutive quarters. Laboratory analysis of groundwater samples collected during the following two quarters, however, indicated that hydrocarbon compounds in groundwater had increased in several monitoring wells.

Challenge

The AS system was restarted in October, 2005 and operated on an approximate 2-week-on and 2-week-off cycle through February, 2009, when it was shut down based on non-detectable hydrocarbon concentrations in all but one groundwater monitoring well, MW-3. As a remediation strategy to address TPH-g and benzene impacts that remained in well MW-3, sulfate injection was proposed. However, due to high sulfate concentrations observed in the down-gradient monitoring well, MW-9, the sulfate injections were suspended in November of 2012 and evaluations of other chemical injection methods were proposed.

REGENESIS Remediation Services (RRS) recommended PlumeStop injection and completed two soil borings for design verification testing in November, 2015. Soils on-site were primarily sand and gravel, with two, 4-6” clayey silt layers—one at approximately five feet and the other at 10.5 feet below ground surface (bgs). Based on field screening with photoionization (PID), contamination appeared to be concentrated at the 8-9 feet depth interval, a point at which soil increasingly hardens. With results of a laboratory analysis, RRS modified the design, adjusting the vertical treatment interval from 5-12 feet below ground surface to 7-11 feet, with the concentrations and quantities of PlumeStop and ORC-A remaining unchanged.

Solution

REGENESIS Remediation Services (RRS) injected approximately 200 gallons of PlumeStop 6,000 ppm solution into on-site wells IW-1 and SVE-1 December, 2015. Using strategically placed point locations to rapidly reduce contaminant concentrations, Direct Push Technology (DPT) was employed to advance injection points throughout the treatment zone at each respective injection point location. The following day, the solution was increased to 12,000 ppm, 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 chemistry and complete the application on schedule.

A total of nine (9) PlumeStop DPT injection points were cleared to 5 feet below ground surface pre-injection, and during the course of the injection seven (7) point locations were advanced to a depth of 11 feet below ground surface and retracted to a depth of 7 feet below ground surface using 1.50 inch outer diameter (O.D) Geoprobe® injection rods with retractable screen tooling.

Additionally, 120 pounds of ORC-A were applied at approximately 30% solution (w/w) in cleared boreholes via a backfilling method, which involved drilling to the target depth, retracting the rods and pouring the ORC-A slurry down open boreholes to approximately 5 feet below ground surface in order to properly abandon points.

Results

During the course of the injection and at the end of the application, increases in groundwater levels were observed in monitoring wells MW-3 and MW-9 in the treatment area. Additionally, increases in ORP (oxidation reduction potential) were observed in MW-2, MW-3, MW-6, MW-7, MW-8, and MW-9. Increases in dissolved oxygen were also noted post-injection in MW-2, MW-3, MW-6, MW-7, MW-8, and MW-9.

The successful and rapid reduction of petroleum hydrocarbon contaminant concentrations in soil and groundwater was achieved within approximately 24 hours, despite difficulty injecting the material via direct-push injection points. With field modifications, RRS was able to not only mitigate surfacing issues by switching to injection via injection well application but also observe the desired distribution of the remediation chemistry in the subsurface.

In the same way the State of Washington Department of Ecology continues to take steps and implement tools that will streamline the cleanup process even further, REGENESIS recognizes the critical need for cost-effective, sustainable and environmentally sound remediation solutions. Whether pioneering new in situ technologies in the lab or rolling up its sleeves in the field to ensure a successful project outcome, REGENESIS remains committed to advancing the remediation industry for the benefit of its partners as well as for the future of the world at large.

How PlumeStop® Brings Sites to Permanent Closure

PlumeStop rapidly removes contaminants from groundwater and stimulates their permanent degradation. This exciting, turn-key solution offers several key benefits for addressing brownfield site treatment, including:

  • Rapid reduction of dissolved-phase plumes
  • Distribution of widely under low injection pressures
  • Achievement of stringent groundwater clean-up standards
  • Providing a long-term means of addressing matrix back–diffusion
  • Elimination of excessive time and end-point uncertainty associated with 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 expediting permanent contaminant biodegradation. This unique remediation technology accomplishes treatment with the use of highly dispersible, fast-acting, sorption-based technology which captures and concentrates dissolved-phase contaminants within its matrix-like structure. When contaminants are sorbed onto the regenerative matrix, biodegradation processes achieve complete remediation at an accelerated rate, leading to successful site treatment.

remediation case study

Redevelopment of former gas works unlocked by combining technologies

Estimated Reading Time: 5 minutes

Integrated remediation strategy provides rapid and cost-effective clean up

 

Fig. 1 – Remedial works at residential construction site
  • During the construction of multiple residential dwelling it became apparent that a historical gas works had previously occupied the site.
  • A targeted site investigation needed to be completed quickly to identify the areas requiring remedial action, enabling construction to continue in plots outside of the plume.
  • A combined remedial strategy was required to address soil, LNAPL, DNAPL and dissolved phase contamination.
  • The implementation of the treatment had to be completed around partially completed housing and live underground services.
  • The remedial works had to be completed quickly in a manner as to not impact the build program.
  • The strategy needed to provide appropriate protection to both human health and controlled waters.
  • The need to respond and act quickly required excellent communication and good working relationships to be established between the consultant, stakeholders, regulators and multiple specialist remediation contractors and suppliers.
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Remedial Approach

A wide range of remediation technologies were deployed sequentially and in parallel to provide the most rapid and cost effective clean up:

  • Ex situ bio-piling of hydrocarbon impacted soils
  • LNAPL skimming
  • Pump and treat (P&T) of dissolved phase contamination
  • DNAPL pumping and settlement/collection
  • Enhanced abstraction of contaminant mass using PetroCleanze
  • In Situ chemical oxidation (ISCO) using RegenOx, which is compatible with footings and services already in place
  • Accelerated aerobic natural attenuation using ORC Advanced slurry
  • Accelerated aerobic natural attenuation using a pelletised oxygen-release compound (ORC Advanced) placed in the backfill
  • PlumeStop Liquid Activated Carbon injection to install a subsurface activated carbon filter to adsorb and biologically degrade dissolved phase contamination
  • Gas vapour membrane installation

Ex situ treatment

The impacted materials within the unsaturated zones within Plume A and B were excavated and placed in a biopile for onsite treatment (Figure 1). Nutrients were added and the biopile was turned until remedial targets were achieved. The soils were then backfilled under the CL:AIRE Code of Practice. Prior to backfill with the remediated soils, ORC Advanced Pellets were added to the base of the excavation. This provided a source of dissolved oxygen for up to a year, stimulating the growth of an effective aerobic biomass and accelerating the degradation of the petroleum hydrocarbon contamination.

Fig. 2 – Details of Ex-Situ Treatment

In Situ Treatment

The southern part of Plume A was made inaccessible by footings and services; here in-situ treatment was completed accommodate these obstructions without compromising treatment efficacy. Within Plume B, where high levels of contamination had been encountered (Figure 2), several in situ remedial actions were taken as appropriate to concentration, location and sequence in the strategy:

  • REGENESIS injected PlumeStop, a micron-scale colloidal Liquid Activated Carbon substrate along the western margin of the site via direct push to protect the offsite surface water. PlumeStop creates a subsurface activated carbon filter which adsorbs the contaminant influx, which is then degraded by the microbial growth on the carbon biomatrix. Biological degradation was also accelerated through co-application of ORC Advanced and the presence of the pelletised ORC placed in the base of the excavation upgradient, providing a controlled release of oxygen.
  • Where LNAPL and high dissolved phase concentrations were observed, a network of injection boreholes were installed by Rake Remediation/REGENESIS. Many of the wells were installed by removing suspended floors and lifting in a mini-rig to complete the drilling beneath partially constructed dwellings. Through these wells, multiple applications of RegenOx were completed. This in situ chemical oxidant was chosen as it was safe to handle on this busy site and would not corrode services installed at the site, nor would it be detrimental to the concrete footings.
Fig. 3 – Details of In Situ Treatment

  • Following the ISCO, ORC Advanced slurry was injected to enhance the natural attenuation (ENA) of the residual dissolved phase contamination to low levels.
  • In Plume B, high levels of contamination in the form of both L- and DNAPL were encountered. This was removed using a P&T system augmented with PetroCleanze, an inorganic surfactant that uses a high pH, carbonates, silicates and partial oxidation to remove contaminants from soils. The PetroCleanze was injected to produce a temporary desorption event, which once observed, allowed the P&T system to be switched back for a short period to remove the contamination. This process was repeated three times to maximise the efficacy of the P&T and shorten the treatment programme.
  • Once the NAPL was removed, multiple rounds of RegenOx were completed, followed by ORC Advanced via injection through wells.
  • Long term groundwater monitoring programme was put in place to monitor the effectiveness of the clean-up.

Results

The following graphs (Figures 7 and 8) show the variations in concentrations for selected priority contaminants of concern over the monitoring period for Plume A and B. These show a marked reduction in the hydrocarbon dissolved phase concentrations over time, with compliance achieved with the remedial criteria.

Fig. 7 – Plume A: Benzene concentrations over time. (red line = DQRA)
Fig. 8 – Plume B: Aromatic C8-C10 concentrations over time (red line = DQRA)

Conclusion

Complimentary remedial technologies were combined successfully to achieve:

  • Contaminant mass reduction to below remedial targets in the soil and groundwater within 6 months.
  • Protection of onsite and offsite receptors.
  • Written confirmation by the Environment Agency that they ‘agree with (the reports’) conclusions’ and that ‘development may proceed’.
  • Remediation completed on a tight budget – as remediation had not been foreseen by the developer.
  • Ex-Situ remediation of soils and their reuse on site under the CL:AIRE CoP avoided offsite disposal of ~800m3 to landfill.
  • In Situ enhancement of the P&T system, minimising the time, cost and volume of abstraction required.
  • By combining the technologies intelligently, both simultaneously and sequentially, the programme length was minimised – allowing construction to continue within only 6 months.

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).

Integrated remediation at a motorway petrol station in Lombardia, Italy

Integrated remediation at a motorway petrol station in Lombardia, Italy

Estimated Reading Time: 6 minutes

Introduction

A large petrol station located along one of the busiest motorways in northern Italy was undergoing extensive reconstruction, including the demolition of existing buildings, removal of above- and below-ground structures; as well as remediation. The existing underground fuel tanks (USTs) were removed and the contaminated soil surrounding the USTs was excavated to a depth of 5m BGL.

The geology consists of a highly permeable soil comprising sand and gravel to approx. 40m BGL. The average groundwater level is at approximately 4m to 6m BGL, where an extensive contaminant smear zone was observed.

The main excavation was approx. 1,100m2 and 5m deep, with the extent and depth limited by the proximity of the motorway (as well as the presence of groundwater).

The soil at the bottom of the excavation was highly impacted with Total Petroleum Hydrocarbons (TPHs) and BTEX compounds, with concentrations of up to 10,000mg/kg. The groundwater inside the excavation was highly contaminated, with evidence of Light Non Aqueous Phase Liquid (LNAPL) and average concentrations in the range of 500,000μg/L.

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Design Approach & Planning

For any treatment approach on this site, to be effective in improving the groundwater quality, it would have to be able to address this secondary source in addition to treating the residual dissolved contamination. The remedial approach also needed to be rapid and effective, in order to allow for immediate back filling. This was because a delay in the construction program would result in a loss of income if the petrol station was not opened on time.
REGENESIS and the Environmental Consultant created an intelligent treatment strategy that took these challenges on board. The remediation approach comprised:

Phase I: Removal of the main contaminant mass present in the saturated soil. This was achieved via Enhanced Chemical Desorption using PetroCleanze, followed by physical abstraction using a vacuum tanker;

Phase II: In Situ biodegradation of the residual dissolved contamination over a period of 9 to 12 months following back fill, via Enhanced Aerobic Biodegradation using ORC Advanced.

PetroCleanze has been developed by REGENESIS to enhance the desorption of contaminants from soil, so that these can be recovered by physical treatment systems. It provides a cost-effective solution for the in-situ treatment of saturated contamination and smear zones. This allows physical treatment systems to be more effective over a shorter period of time, lowering asymptotes and reducing rebound due to ongoing desorption from the smear zone.

When applied in excavation areas, application is quick and desorbed contaminants can be recovered really easily. Usually two to three application and abstraction rounds are required to remove the bulk of the contamination. PetroCleanze is an inorganic technology and therefore avoids introducing a large oxygen demand (as occurs with using surfactants) and promotes enhanced biological degradation of the residual contamination.

PetroCleanze has been developed by REGENESIS to enhance the desorption of contaminants from soil, so that these can be recovered by physical treatment systems. It provides a cost-effective solution for the in-situ treatment of saturated contamination and smear zones. This allows physical treatment systems to be more effective over a shorter period of time, lowering asymptotes and reducing rebound due to ongoing desorption from the smear zone.

When applied in excavation areas, application is quick and desorbed contaminants can be recovered really easily. Usually two to three application and abstraction rounds are required to remove the bulk of the contamination. PetroCleanze is an inorganic technology and therefore avoids introducing a large oxygen demand (as occurs with using surfactants) and promotes enhanced biological degradation of the residual contamination.

Phase I – Enhanced Desorption and Extraction

  • Before application, the excavation was divided in seven segments, leaving some pathways for excavator passage. For each segment, a specific PetroCleanze application dose was defined.
  • PetroCleanze was applied in each sub-area through the dig and mixed directly with the remaining impacted soil. Due to the high contaminant mass present in some of the areas, LNAPL appeared on the water in less than one hour after the first application (the photos shown overleaf were taken 30 minutes after application).
  • The LNAPL was subsequently removed by selective pumping using a vacuum tanker.
  • Repeated soil mixing and desorbed LNAPL removal took place over the following days across the whole area (for a maximum of 3 cycles in the most contaminated areas).
  • The repeated soil-mixing allowed for ongoing desorption and removal of the contamination without the need to add more PetroCleanze. This process was continued for all the sub-areas until no more recoverable free phase was present.
  • Finally, a short period of de-watering was completed to remove part of the residual dissolved phase contamination, with water samples taken before and after.

Phase II – Enhanced Aerobic Natural Attenuation

Following the initial excavation and enhanced desorption treatment, an ORC Advanced application was completed. This targeted the residual dissolved phase contamination. The ORC Advanced provided a controlled release of dissolved oxygen in order to stimulate and maintain enhanced aerobic biological degradation of the groundwater contamination for 9-12 months from the single application. This meant that the excavation could be immediately back filled and the construction continued. The remediation of the dissolved phase contamination therefore continued in situ, with no further operational costs and no disruption to the build programme.

To optimise the application process onsite, a pelletised version of ORC Advanced was chosen. This is because they can be applied directly in the excavation without the need for pre-mixing with water. The Pellets also minimise dust formation during application. The pit application was cost-effective, as it did not require additional equipment to be used on site and the application and mixing was safe, quick and straightforward.

Results

  • The remediation activities were completed in approximately 40 days on site, which included the product applications, soil mixing, selective pumping and final pump and treat.
  • During this period, more than 400L of petroleum hydrocarbon LNAPL was successfully recovered, as well as approx. 100m3 of highly contaminated groundwater with TPH concentrations in the 100,000-1,000,000μg/L range.
  • In addition, 280m3 of contaminated groundwater was removed during the final pump and treat activity (before the ORC Advanced application).
  • During desorption and removal, no increase in dissolved phase concentrations was seen in the wells immediately downgradient of the excavation, or on the site boundary. This showed that all desorbed contaminants were successfully extracted during the treatment process.
  • Subsequent groundwater monitoring shows a significant decrease in concentrations, avoiding any potential delay to the construction programme. The figure below shows the petroleum hydrocarbon concentrations for each sub-area at baseline (blue), during treatment (orange) and after pump and treat (grey).

Conclusion

  • The site was remediated on time without disruption to the construction program through the use of enhanced desorption and removal, followed by in situ enhanced aerobic biological degradation.
  • An integrated remedial approach was created to target each contaminant type/phase, through excavation of impacted soils, enhanced desorption and extraction of LNAPL and high levels of TPH in the groundwater contamination, to biological degradation of the residual dissolved phase contamination.
  • Treatment was limited to the target area with the remediation works producing no increase in downgradient contaminant concentrations.