In 2016, environmental investigations at the Army Aviation Centre, Oakey, identiﬁed per- and polyﬂuoroalkyl substances (PFAS) contamination in both ground and surface water. The contaminated water had migrated offsite over time which resulted in restrictions on the use of ground and surface water for surrounding properties. To mitigate the long-term impacts of the PFAS contamination, the Australian Department of Defence (Defence) implemented active groundwater remediation activities to treat the water, beginning in 2017.
ECT2 was contracted by Defence to design, fabricate, and operate a water treatment system to reduce PFAS contamination in groundwater below the Base and minimize contaminated groundwater from migrating to surrounding properties. The surrounding properties include residential properties where water is extracted via bores for domestic purposes as well as for irrigation and stock watering. When the need for water treatment first arose, there were limited proven technologies available to remove PFAS from groundwater. Shortly after contract award, the regulatory guidelines changed from the interim guidance values of 0.5µg/l PFOS and 5 µg/L PFOA to 0.07 µg/L sum of PFOS+PFHxS and 0.56µg/l PFOA.
The water treatment system was fabricated inside a 40-foot shipping container and transported to the site for installation in July 2017. The treatment system has been operational since September 2017 and as of May 2021, has treated over 173 million litres of water with no exceedances of the treated water criteria. The treated water is then reinjected into the aquifer, and used for irrigation and in construction related activities such as dust suppression. Since operations commenced in 2017, less than 3 IBCs of waste has been generated and the treatment system has averaged >99% uptime when operating 24/7.