Six Pilot-Scale Studies Evaluating the In Situ Treatment of PFAS in Groundwater
Reduced to Non-Detect
from PFAS with Colloidal
Treatment Solutions for PFAS Plumes
There has been an increasing awareness to the widespread contamination associated with per- and polyfluorinated alkyl substances (PFAS). With a lack of effective remediation options to degrade PFAS, including PFOS, PFAS etc., there is an established need to mitigate or eliminate the risk that these contaminants pose, particularly when it comes to their characteristics of being large, dilute plumes with very low regulatory limits. At the present time, the accepted remediation method is to use pump and treat systems, that usually have exorbitant associated costs. Because we cannot (yet) destruct or degrade PFAS efficiently in groundwater, we need to look at innovative strategies, such as elimination of risk, to address these contaminants.
REGENESIS has developed and field-tested an in situ colloidal activated carbon remedy called PlumeStop®, that can cut off and contain PFAS plumes for many years at PFAS contaminated sites. This solution for PFAS plumes forms a cost-effective means to decrease or avoid the operating and maintenance costs of above-ground treatment systems. We are working with several environmental consultancies, problem holders and universities around the world on the challenges that PFAS poses in the environment and have completed a number of successful, field pilot and full-scale applications with colloidal activated carbon. The short video on the right-hand side explains how it works.
Third-Party Research Article Publications
Three third-party research articles have been published in Wiley’s peer-reviewed Remediation Journal on in situ PFAS treatment solution using colloidal activated carbon. Click the links below for more information and download the research articles:
Six Pilot-Scale Studies Evaluating the In Situ Treatment of PFAS
Author: Rick McGregor (In Situ Remediation Services Ltd.)
- This paper reviews six pilot-scale in situ field studies of an unconfined sand aquifer impacted by both petroleum hydrocarbons and PFAS
- Performance results gathered downgradient of each of the permeable reactive zones are provided, up to 18-months post application
- PlumeStop (colloidal activated carbon) is the only reagent that reduces PFAS to below detection limits *and* prevented contaminant breakthrough
Evaluating the Longevity of a PFAS In Situ Colloidal Activated Carbon Remedy
- This research article uses various visualization and modeling methods to evaluate the in situ remediation of PFAS at a site in Canada. A three-dimensional reactive transport model (ISR-MT3DMS) was used to indicate the CAC remedy implemented is likely to be effective for decades.
- Due to the relatively low cost to implement the CAC, and the ability to adapt the remedy in the future, this remediation approach is deemed to be viable at other PFAS sites.
Treatment of PFAS-Impacted Water Using Colloidal Activated Carbon
Author: Rick McGregor (In Situ Remediation Services Ltd.)
- This third-party research article reviews a site impacted with PFOS, PFOA and other PFAS
- A single application of PlumeStop resulted in a significant reduction
- 18+month post-application data available
- Modeling indicates that the PlumeStop application event should keep the PFAS contained within the source area for decades
- Details of the remedial design approach are provided along with results of its implementation
PFAS Groundwater Remediation Strategies
With PlumeStop, remediation professionals gain a solution that will provide an effective, more economical means of stopping the migration of PFAS plumes, thereby protecting sensitive receptors. There are many possible strategies for the in situ containment of PFAS using PlumeStop. Here are some examples:
Strategy #1: Simple Plume Cut-Off Barrier
In this application, a single barrier of PlumeStop can be applied to limit plume expansion. The purpose of the application is to protect a property boundary from a plume entering or exiting a site. It can also protect receptors such as a well or water body and minimize the plume in order to contain liability.
Strategy #2: Sequence of Barriers
PlumeStop can also be injected as a sequence of multiple barriers designed to progressively eliminate the PFAS plume. The benefits of this approach are that it addresses the entire plume and is particularly suited for large plumes and built up areas with restricted access.
Strategy #3: Localized Receptor Protection
Because PFAS plumes tend to be extremely large and dilute, remediation professionals will likely need to turn to interim measures like this one to protect local receptors. Acting like a “Brita®” filter in the ground, the PlumeStop can be injected around extraction wells to protect them in the event that an entire plume cannot be quickly contained.
Groundwater Treatment of PFAS
To date, the use of traditional means of groundwater remediation of PFAS plumes has proven difficult. Because they are extremely robust compounds, remediation technologies such as in situ chemical oxidation (ISCO) and various forms of bioremediation have been unable to address these contaminants. The most prevalent method at this time is to use an ex situ pump and treat system with activated carbon filters. However, this process can prove very expensive and challenging due to the extremely wide-area, dilute formation of the most common PFAS plumes.
REGENESIS has developed an in situ remediation product called PlumeStop® Liquid Activated Carbon™ that has the potential to solve the challenges faced in the groundwater remediation of PFAS. This technology can be applied under low-pressure injection, which solves the problem of excessive costs incurred with pump and treat systems. Through the use of a proprietary organic polymer dispersion chemistry, the activated carbon achieves high distribution through the subsurface and removes contaminants like PFAS rapidly from groundwater.