Extensive environmental investigations at RAAF Base Williamtown commencing in 2014 identiﬁed per- and polyﬂuoroalkyl substances (PFAS) contamination in ground and surface water that migrated offsite, resulting in restrictions on the use of ground and surface water for surrounding properties. To mitigate the long-term impacts of the PFAS contamination, the Department of Defence (Defence) identiﬁed two groundwater source areas for active management: the former ﬁre training area (FFTA) within the Base, and the Southern area which extends both on and off Base, to the south of Lake Cochran.
ECT2 were contracted to install and operate multiple water treatment systems to assist Defence in managing PFAS contamination on and in the vicinity of the Base, including groundwater treatment systems for the FFTA and the Southern area. Given the volume of groundwater that required treatment, a critical challenge was not only to ensure that the selected water treatment technology would reduce PFAS levels in treated water to health based guidance values (HBGV) established for drinking water, but to do so in an environmentally sustainable way, minimising waste generation that would require further management.
In order to meet the established performance and sustainability objectives, ECT2 designed, fabricated, delivered and installed two groundwater treatment systems, employing the company’s proprietary SORBIXTM RePURE regenerable resin. The treatment system for the FFTA source area was designed and fabricated in two 53-foot shipping containers, and the Southern area treatment system was designed and fabricated inside a single modiﬁed 53-foot shipping container. In addition, a system to enable the regeneration of the SORBIX RePURE resins from both groundwater treatment systems, as well as in an ECT2 surface water treatment system on the Base, was housed in a 40-foot shipping container.
The resin is regenerated using ECT2’s patented technology, which involves a speciality brine ﬂowing through the resin to remove PFAS from the resin beads. Removing PFAS from SORBIX is only possible due to ECT2’s extensive research and the development of the speciality brine. Without the exact brine mixture, PFAS would remain adhered to the resin beads. Following removal of PFAS from SORBIX, the PFAS laden brine is processed through ECT2’s regenerant recovery and SuperloadingTM process. This regeneration process allows SORBIX to be conﬁdently reused rather than sent for subsequent treatment using thermal desorption or landﬁlled for future generations to contend with.
The FFTA treatment system has been operational since July 2018. The regeneration system has been operational since September 2018, and the Southern area treatment system has been operating since April 2019. The groundwater treatment systems manage ﬂows of in excess of 25 L/sec allowing 2.1 million litres of water to be treated daily, and the ability to regenerate resin results in approximately one litre of waste being generated for each one million litres of water treated. By mid March 2020, the groundwater treatment systems had treated over 830 million litres of groundwater, and the regeneration system had conducted 17 regenerations of media that would have otherwise been sent offsite for further treatment and disposal.
There have been no exceedances of the established criteria in treated water.