Resin is being changed in the per- and polyfluoroalkyl substances (PFAS) treatment plant located at the Katherine Water Treatment Plant as part of routine maintenance to ensure that PFAS continue to be effectively removed.
Senior Engineer Water and Wastewater Treatment at Power and Water, Skefos Tsoukalis, said the interim pilot treatment plant has been successfully operating in Katherine since October 2017 and has treated over 400 million litres of groundwater.
“The treatment process is in three stages,” Mr Tsoukalis said.
“Groundwater passes through a filter for pre-treatment while removing organic matter. An antiscalant is then added to reduce the amount of calcium in the water.
“The water is then passed through a series of filters containing a synthetic resin. These small plastic beads of resin have a unique chemical holding capacity that removes PFAS from the water.
“The filtered water is then blended with the treated Katherine River water. A small amount of chlorine is added to keep your water safe all the way to your tap.”
When the resin becomes fully saturated with PFAS, it is removed and replaced with new resin.
“We monitor the resin to determine when it has become saturated and requires changing,” Mr Tsoukalis said.
“We anticipated it would be within 12 to 18 months of use and the resin is now due to be replaced.
“This process will take place over the next week while water use is low. We will fill the storage tanks to capacity to maximise our supply capability during the changeover.
“The PFAS treatment plant will be taken offline and river water will be used to maintain the water supply for the duration of the maintenance work.”
The ten cubic metres of resin will be stored securely onsite before half is safely transported by Defence to RAAF Base Tindal for regeneration. PFAS extracted in the process will be later disposed of at an authorised interstate facility. The other half of the resin, which is non-regenerable, will be transported by Defence to a licensed waste facility interstate for destruction, in accordance with state and federal environmental regulations.
Since the interim pilot treatment plant has been operational, based on regular testing results, there have been no detectable levels of PFAS in Katherine’s treated water supply derived from Power and Water’s facilities.