City of Darwin, NT
Innovative Leachate Treatment System
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The Initiative
City of Darwin has applied an innovative solution in effectively managing leachate and protecting the local environment. The leachate treatment system is the first in the world treating PFAS in leachate coupled with biological and ecological treatment and zero disposal – a closed loop system Leachate is a toxic liquid generated in landfills, posing a significant management challenge to landfill owners around the world. Leachate contains heavy metals, nutrients, and persistent chemicals such as PFAS. While nutrient and heavy metals can be effectively removed with the current available technology, PFAS removal from contaminated raw leachate is technically challenging often requiring a combination of multiple technologies.
To address the problem of leachate in Darwin’s high rainfall climate, City of Darwin partnered with Water Carbon Group (WCG) to facilitate a research and development project for a chemical free and affordable PFAS removal technology. Following the successful demonstration of the technology, the City of Darwin awarded WCG with a $13.2 million contract to design, construct, and operate the innovative leachate treatment plant, the first of its kind in Australia.
Solution
The Leachate Treatment Plant uses a world first innovation called Low-Energy Evaporative Fractionation (LEEF) system to remove PFAS from leachate. The air bubbles injected in the raw leachate allows PFAS to attach to the bubbles and be skimmed from the water as a foam without chemicals and with minimal energy use.
Treated effluent from the LEEF System® is then further processed via a biological treatment plant which utilises microbes for nutrient removal. Finally, the treated leachate is irrigated onto a Vetiver grass crop growing on the capped landfill, where the roots of the Vetiver plants stabilise the landfill cap and draw up residual contaminants, resulting in zero discharge.
Outcomes
This sustainable, cutting-edge leachate treatment solution supports the City of Darwin’s commitment to protecting the environment.
The leachate treatment system is the first in the world treating PFAS in leachate coupled with biological and ecological treatment and zero disposal – a closed loop system. The plant uses zero chemicals, low energy, processing up to 140,000 litres of raw leachate a day.
The development of the LEEF System® through an intellectual property agreement is an outstanding example of how local government and the private sector can partner to innovate and solve emerging environmental challenges.
About the Category
The ‘Waste Management’ category recognises local government initiatives which:
- improve resource recovery and reduce amounts of waste generated in order to benefit human health, the environment and the economy;
- increase use of recycled material and build demand and markets for recycled products;
- better manage input and output of waste materials, to benefit human health, environment and economy;
- improve information to support innovation, guide investment and enable informed community decisions relating to waste management; and/or
- support the transition to a circular economy by transforming waste into sustainable resources.
Successful initiatives in this award category benefit communities by:
- creating employment opportunities, protecting the environment, and better managing valuable and finite resources;
- recognising the opportunities waste materials can provide and the economic value they retain; and/or
- accelerating the recovery and reuse of community resources.