The historical use of fire-fighting foam containing various per- and polyfluroroalkyl substances, commonly known as PFAS, at the Royal Australian Air Force (RAAF) Base Williamtown led to groundwater and stormwater contamination at the base. The Australian Department of Defence (Defence) needed to quickly identify the right technology to address this challenge, which was compounded by tightening PFAS regulatory requirements, an aggressive schedule and strict waste disposal limits.
Defence contracted ECT to tackle this difficult project because of its regenerable ion exchange resin technology and experience delivering turnkey, modular solutions to address similar PFAS challenges.
For phase 1 of the project, ECT designed, fabricated, assisted with delivery and installation, and performed startup/commissioning and operation of a 50-gallon per minute (192 liters per minute) PFAS removal system. ECT designed the system to treat stormwater with influent PFAS concentrations in the range of 1 to 120 parts per billion. Actual influent PFAS concentrations have been at the lower end of this range, averaging 7,500 parts per billion. The system consists of pretreatment filtration to remove iron and solids, followed by PFAS removal using multiple vessels in series (lead/lag configuration) containing ion exchange resin.
Two vessels filled with ECT’s Sorbix A3F resin were initially specified to provide consistent compliance with the original target limits of 0.5 ug/l for PFOS + PFHxS, and 5 ug/l for PFOA. The Australian Commonwealth Department of Health subsequently lowered drinking water quality standards by roughly an order of magnitude to 0.07 ug/l and 0.56 ug/l, respectively, before the system was delivered to Williamtown. After the treatment system was delivered, the treatment objective was lowered even further to LOR (i.e., less than the limit of reporting) for all 22 monitored PFAS. ECT adjusted to the changing treatment goals by adding two polish vessels at the tail end of the existing treatment train. Each of the polish vessels contains Sorbix LC1, a specialized resin that effectively removes an array of PFAS compounds, including the more difficult to remove short-chain compounds.
The treatment system was designed and fabricated in the U.S., and delivered to the site, installed and started up in less than 14 weeks after the contract was signed. Adherence to this tight schedule was made possible largely by two primary factors:
- ECT installed the treatment system inside international shipping containers to facilitate ease of transport, mobility/flexibility and rapid onsite readiness (i.e., “plug and play”). By fabricating and testing the system in its central shop, ECT ensured quality construction and performed operational debugging, which translated directly into saving time and money on the startup.
- Defence accelerated the delivery schedule by five weeks by air-freighting the system from Westover Air Force Base in Chicopee, Massachusetts, to Australia in a C17 Globemaster III transport plane.
The Phase 1 treatment system started up smoothly in June 2017 and has consistently achieved less than limit of reporting for all PFAS of concern. Phase 2 of the project will consist of installing a larger, 200-gallon per minute (750 liters per minute) PFAS removal system, which will include a resin regeneration system, to treat site groundwater at one of the identified source areas on the site, possibly the former Fire Training Area.