PFAS is everywhere in the environment and top of mind for environmental consultants. In this issue of Pathways, you’ll find the latest insights and technology options for PFAS characterization and remedial strategies. As always, we welcome your feedback and suggestions for future topics.
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Effective PFAS remediation requires a holistic approach. A remedial strategy for plumes may not be optimal for the source zone.
Thermal conductive heating (TCH) is a promising technology for the remediation of highly concentrated PFAS-contaminated source zones. TCH can be applied either in situ or ex situ in specially constructed piles and involves the insertion of heaters into the contaminated media (soil, sludge, sediment, soil washing fines, etc.), and the application of heat to the subsurface to reach the temperatures that can volatilize and thermally degrade the PFAS, typically 350 to 400C.
Source zone treatment via TCH has advantages over other PFAS remediation technologies. One being that TCH can treat the complete range of target as well as non-target PFAS compounds, today's and tomorrow’s regulated contaminants. TerraTherm’s approach for TCH also incorporates innovative high-temperature thermal treatment of extracted vapors to essentially eliminate discharge of PFAS compounds to the atmosphere and meet stringent air emission standards. Importantly, the complete destruction of PFAS compounds provided by TCH, eliminates long-term liabilities of other treatment approaches based on in situ stabilization or excavation and landfill disposal.
Check out recent thermal treatment of PFAS research or view webinar on treatment strategies for high concentration of PFAS in source zones.
Even with successful source zone treatment of soil, PFAS groundwater concentrations remain a concern. How can you cost-effectively address the groundwater plume? ColloidalChem is a group of high mobility and low pressure, injectable colloidal activated carbon products designed to target difficult-to-treat contaminants like PFAS. ColloidalChem +Anchor is a patented injectable colloidal activated carbon with an integrated enzyme technology to control mobility in permeable reactive barrier applications.
These amendments are easily injected with our Pathfinder™ technology, the industry’s first fully automated injection system, into transmissive zones contributing to PFAS Flux.
Data collected in our R&D lab indicates that ColloidalChem can meet EPA’s proposed MCLs. Additionally, Cascade can anchor the high mobility ColloidalChem within the PRB with ColloidalChem +Anchor technology. This anchoring technology is critical to the efficacy of PRBs for higher seepage velocities, which is typically the case in transmissive flux zones.
Pictured left to right: ColloidalChem™ for Department of Defense testing a sample of the injectable colloidal activated carbon product ColloidalChem, 55-gallon drums of ColloidalChem ready for injection.
Watch the webinar to learn about contaminant flux characterization and design optimization testing for PFAS plume treatment.
How do you manage PFAS vapor emissions during thermal treatment?
Evaluating PFAS vapor emissions has been an emerging topic of interest in the environmental community and TerraTherm’s recent research has investigated this question. In a bench scale study thermally treating PFAS spiked sand at 350C for 7 days, TerraTherm proved the effectiveness of a vapor treatment catalytic media combined with 0.1N sodium hydroxide to further neutralize the vapor stream. Vapor samples collected after these two vapor treatment steps on the bench scale resulted in non-detect concentrations of target PFAS compounds. Furthermore, using a combustion ion chromatography (CIC) technique to close the fluorine mass balance and track the fate of fluorinated compounds in our experiment, we discovered that approximately 42% of the fluorine mass (not in the form of target PFAS) remained in the soil while 46% was captured in the vapor catalytic treatment media. The 0.1N sodium hydroxide treatment step captured an additional 12% of fluorine mass, leaving less than 0.01% of mass in the vapor emissions. TerraTherm is optimistic that these bench scale results can be replicated on a larger field scale, and research proposals and partnerships are underway to further characterize vapor emissions from thermal remediation systems.
Do you have a question for our team? Ask it here and we’ll answer in an upcoming issue.
Meet Kellie, your new Client Services Manager!
With over eight years of experience as an environmental consultant and a licensed geologist in Washington, Kellie brings a wealth of knowledge and expertise to our team.
As your go-to person for seamless access to combined remedies, Kellie is committed to ensuring your projects run smoothly from concept to completion.
Reach out to her with your drilling, site characterization and remediation questions at [email protected].
The key to designing permeable reactive barriers (PRBs) for PFAS will be understanding the PFAS flux leaving the site. Our WaterlooAPS™ technology is a complete direct push subsurface data collection platform, combining high-quality discrete sampling capability with continuous, real-time hydrostratigraphic logging.
The WaterlooAPS has successfully defined PFAS flux during site characterizations. The data collected helps consultants make informed decisions on the best technical approach for the treatment of PFAS plumes emanating from source areas or at property boundaries.
Our Aquifer Drilling and Testing (ADT) fleet is home to one of three shallow draft lift boats on the East Coast. The rig pictured above has passed multiple OVID inspections and has been customized with multiple moon pools for mud rotary, CPT, and Sonic operations.
A lift boat is a self-elevating vessel with a crane and open deck space. Lift boats serve as a stable platform for overwater drilling, allowing crews to operate in shallow water with little interruption from the changing tide.
The NYC-based crews specialize in mud rotary, direct push, CPT, and sonic drilling technologies, providing valuable subsurface information. With their advanced equipment, they can determine important data such as depth to water and bedrock, formation type, blow counts, and more.
Watch this webinar to learn more about overwater drilling or read this case study to get an idea of how overwater drilling supports critical infrastructure projects.
June 1-2, 2023
