Infrastructure services firm AECOM announced the launch of DE-FLUORO™, a technology said to effectively and permanently remove per- and poly-fluoroalkyl substances (known as ‘PFAS’) at the CleanUp 2019 site remediation conference which took place 8-12 September in Adelaide.
A number of AECOM technical specialists presented findings from the DE-FLUORO™ trials and the DE-FLUORO™ technology was on display at the firm’s stand.
“The same properties that make PFAS so effective in industrial processes and fire-fighting also make them extremely difficult to eliminate from the environment or waste material,” said Dr. Rachael Casson, AECOM’s director of the International PFAS Program. “To date, PFAS in contaminated groundwater or liquids was either stockpiled or incinerated at a huge cost. Working with the University of Georgia, we have developed a solution that can be set up onsite and eliminates PFAS-concentrated liquids in a sustainable and cost-effective way. We are now able to help our clients to meet the stringent regulatory requirements that govern PFAS contamination.”
Developed in collaboration with the University of Georgia in the United States, AECOM has been trialling the DE-FLUORO™ electrochemical oxidation system for the past 12 months. The successful trials have demonstrated that the DE-FLUORO™ electrochemical approach is capable of destroying a diverse range of PFAS samples. During the trials, DE-FLUORO™ removed PFAS from groundwater taken from two fire-training sites, PFAS-impacted surface water, as well as from PFAS-remediated waste solution and Aqueous Film Forming Foam (AFFF) concentrate. The scientific trials used samples provided by organisations from a range of sectors, including aviation, defence, manufacturing and petrochemicals.
“We have been searching for a way to dispose of this contaminant in a safe and cost-effective way for some time”, said Gavin Scherer, AECOM Australia and New Zealand’s PFAS response leader. “We’d like to thank all of the clients that participated in the trials and enabled AECOM to test the efficacy of the technology. Now we are ready to help them clean up a legacy of PFAS that has built up over decades.”
Produced for industrial purposes since the 1950s, the unique properties of PFAS have been exploited for a vast array of commercial and industrial applications; notably in historical formulations of AFFF, which is used to rapidly extinguish fuel-related fires.
Uncertainty globally, and within Australia and New Zealand, in conjunction with the persistent nature of PFAS has resulted in a higher level of environmental regulatory scrutiny, which is expected to continue — and even intensify — over the next decade.
DE-FLUORO™ trials data
The samples provided for AECOM’s PFAS-destruction trials contained a broad range of PFAS concentrations, from extremely low (parts per billion [ppb]) to extremely high (parts per million [ppm]). The sum of PFAS concentrations in client-supplied samples ranged from 27.3 ppb to 6,380,000 ppb (equal to 6,380 ppm).
Concentrations of ‘regulated PFAS’ (perfluorooctane sulfonic acid [PFOS], perfluorooctanoic acid [PFOA] and perfluorohexane sulfonic acid [PFHxS]) in the samples ranged from 13.4 ppb to 5,837,000 ppb (or 5,837 ppm).
As a press release explains, the above data shows that DE-FLUORO™ destroyed between 90 and 100 percent of the total PFAS mass in the majority of samples treated, as well as between 98 and 100 percent of regulated PFAS mass, in all but two samples.
“We are confident that if we had extended the duration of the trials it would have resulted in DE-FLOURO completely removing 100 percent of PFAS from all samples tested,” commented Mr. Scherer.
The AFFF concentrate product was subject to the least PFAS percentage mass reduction by DE-FLUORO™; however, the greatest reductions in PFAS concentrations were observed for this sample. AECOM notes that this is related to the extremely high pre-treatment concentrations of PFAS (6,380,000 parts per billion) and the limited retention times for the trial.
DE-FLUORO™ treats measurable and unmeasurable PFAS compounds with a range of compound signatures.
DE-FLUORO™ is not limited by PFAS concentration, nor by the presence of other contaminants.
Further tests are underway to confirm that extending the treatment duration would enable DE-FLUORO™ to completely eliminate PFAS.
AECOM has been helping clients to understand and remediate PFAS contamination since 2001 and has worked on over 200 PFAS projects, including environmental and human health-risk investigations at RAAF Base Williamtown and the Army Aviation Centre Oakey.