Defence employs PFAS removal technology at Qld site

A wastewater treatment plant has been constructed at the Army Aviation Centre in Oakey, Queensland to remove PFAS (per-and poly-fluoroalkyl substances) from contaminated groundwater. Installed by OPEC Systems, the plant will use OPEC’s Surface Active Foam Fractionation (SAFF) technology to process up to 250,000 L of PFAS-contaminated groundwater per day.

Developed and independently tested by NATA laboratories and PFAS experts over several years, the SAFF system combines water treatment, water polishing and waste minimisation stages to remediate PFAS-contaminated water.

OPEC Systems Managing Director Pete Murphy said, “PFAS remediation technology is in its infancy worldwide, and we have worked extremely hard to create an effective homegrown solution to an international problem.

“We know there is intense global interest in what the Australian Department of Defence is doing with PFAS remediation and I’m immensely proud that our team has delivered such an elegant and effective solution.

“Using the principles of green chemistry, our goal was to create a system which produced minimal waste with zero environmental harm. The strength of our approach is we have leveraged the natural physiochemistry of PFAS molecules to engineer a system which is fast, efficient, sustainable and cost-effective.

“SAFF is a modular and expandable technology which can continuously treat large water volumes using minimal energy or additives. We believe this combination will be a game changer for sustainable large-scale PFAS remediation.”

PFAS are manufactured chemical pollutants found predominantly in a now-discontinued firefighting foam. They have also been used worldwide since the 1950s to make products that resist heat, stains, oil and grease, and water.

In order to remove PFAS, the SAFF multistage process includes:

• Pre-treatment — the installation of groundwater extraction wells, adjustment of water chemistry to optimise PFAS extraction efficiencies, and removal of cross-contaminants and dissolved and suspended solids.
• A multistage, continuous flow, foam fractionation procedure to rapidly remove 99% of target PFAS contaminants from the influent.
• Application of vacuum and solar heat processes to create a PFAS-rich, hyper-concentrate semisolid.
• Use of final polishing technologies to remove the remaining estimated 1% of PFAS in the treated water.
• Safe return of clean water to the environment following final analysis.
   

Murphy continued, “The two aspects of SAFF technology that distinguish us from other approaches are the use of foam fractionation, which exploits the inherent predisposition of PFAS compounds to adhere to specifically sized micro bubbles; and the introduction of a patented vacuum extraction system, which successfully harvests the vast majority of foaming PFAS compounds from the surface of the foam fractionator prior to applying ionic exchange polishing resins.”

Waste minimisation practices are incorporated on site at each stage of PFAS treatment to help achieve zero waste objectives. In addition, the system incorporates solar technology to drive efficiency, minimise waste and reduce energy consumption.

With the capacity to treat systems varying in size from 500 L/h to 100,000 L/h, or more if required, the technology has shown it can remove over 99% of longer-chain PFAS molecules within 2–3 min, with longer processing times and supplementary polishing systems allowing PFAS-contaminated water to be restored to below new Australian drinking water guidelines and, in many instances, below the limits of detection.

The wastewater treatment plant will operate for a 30-month trial period.

Image supplied by OPEC Systems.