Client: City of Darwin
Value: $13.2 million across the entire project
Location: Shoal Bay Waste Management Facility, Darwin, Australia
Located in Australia, the Shoal Bay Waste Management Facility receives more than 180,000 tonnes of waste each year from 164,000 residents who live in the greater Darwin region. Due to the region’s rainfall, the facility also generates large volumes of leachate. This wastewater must be treated and kept out of the surrounding environment, which includes ecologically important eucalypt woodland, coastal wetlands and wildlife habitats.
In 2019, the City of Darwin awarded the Water and Carbon Group (WCG) a $13.2 million contract to design, construct, and operate a leachate treatment plant solution for the Shoal Bay facility. During early studies of the leachate contaminants, it was discovered that per- and poly-fluoroalkyl substances (PFAS) were present in the leachate. To address the PFAS contaminants an alternative treatment solution was needed in conjunction with the conventional biological treatment processes.
Challenge of PFAS
PFAS is a significant pollution challenge all over the world that poses a significant risk to human health and the environment. Often dubbed the ‘forever chemical’, PFAS chemical chains do not break down easily and as a result they are now found in the environment and detected in sewage treatment plants and landfill facilities’ wastewater.
Along with PFAS, other chemicals and contaminants are usually present in leachate from these facilities. Therefore, PFAS removal from heavily contaminated leachate has previously been thought to be too difficult and too expensive to treat.
The City of Darwin and WCG worked together to lead the way in designing an effective and affordable world-first treatment solution which incorporates the LEEF System®.
PFAS removal solution
The Shoal Bay Leachate Treatment Plant uses a Low-Energy Evaporative Fractionation (LEEF) system to remove PFAS from leachate captured onsite. The LEEF System® was designed to extract regulated PFAS contaminants from contaminated water using minimal energy, no chemicals, or consumables.
At Shoal Bay, and in most circumstances, the leachate did not require pre-treatment before foam- fractionation was utilized to remove more than 99% of PFAS contaminants. The removed PFAS was then concentrated into a separate waste stream and passed through a solar array for distillation and further concentration.
The LEEF System® will treat 50 megalitres of leachate each year at the Shoal Bay Leachate Treatment Plant, with the wastewater going through further steps as part of a zero discharge, closed loop solution.
Treating PFAS contaminated leachate
The October 2022 commissioning of the LEEF System® at the Shoal Bay Waste Management Facility is understood to be the first permanent, low-energy, chemical-free solution to treat PFAS contaminated leachate in the world.
The sustainable, innovative PFAS solution has supported City of Darwin’s 2030 Waste and Resource Recovery Strategy and helped fulfil the municipality’s vision to protect the environment from toxic leachate.
The LEEF System® at Shoal Bay is designed to process up to 140,000 litres of leachate a day. However, the modular nature of the system means it could be scaled up to meet higher demand if necessary.
Since commissioning, the LEEF System® is successfully helping meet regulatory environmental licence requirements.
Contact us for more information or a demonstration of the LEEF System® at your site.