Veolia Voice: Turning waste into a resource

As Australia begins to develop energy from waste facilities, it’s crucial to explain how they work, and how Veolia leads the way with our expertise in operating these advanced, state of the art facilities around the world.

Veolia’s global operations and 170 years of experience put us at the forefront of technical knowledge for environmental services, especially in energy from waste operations. These facilities have long been recognised as an alternative to landfill, a way to recover more precious metals and aggregates, and generate a renewable form of energy.

Veolia operates more than 65 energy from waste facilities across the globe, and soon there will be more. Veolia will be operating two in Western Australia, is co-developing one in Maryvale, Victoria, and proposing for another in Tarago, New South Wales.

Modern energy from waste facilities employ advanced technologies that take residual (non-recyclable) waste and turn it into energy through a safe, and highly efficient engineered process. This diverts this waste from landfill - enabling greater recovery of ferrous and non-ferrous metals (including precious ones), higher capture of emissions and the conversion of captured heat into a renewable form of energy.

Continuous innovation in this field has led to the development of highly efficient systems that maximise energy recovery while minimising environmental impact.Their progression into Australia’s resource management mix highlights that this technology has been recognised as safe, and approved by regulators nationally.

WHAT IS INVOLVED?

High-tech processes see residual waste combusted in a highly controlled environment, with forced air injection that maximises the effectiveness of reducing emissions at the combustion stage (known as clean combustion), and using post-combustion processes and air cleansing equipment.

An additional element is the recovery of energy from the combustion process through a purpose built industrial boiler (water tubes creating steam).

Beyond the generation of energy, these facilities also facilitate the recovery of the valuable materials as byproducts during the process, including:

• Bottom ash; non-combustible material (also known as inert) such as minerals, stones, grit, glass and rocks that can be recycled into aggregates for use in the construction industry or in road base;
• Ferrous and non-ferrous metals: These metals are separated and extracted from the bottom ash, enabling their recycling into new metal products, contributing to a circular economy.
• Air pollution control residues (APCr); fine dust is filtered, captured and managed on site - so air pollutants (heavy metals, dioxins) are captured and filtered out of the combustion gases before exhaust through the stack. APCr are then stabilised to reach a non-hazardous threshold to be disposed of in a specialised cell or landfill. Under a specific stabilisation method, APCr can be disposed of in a non-hazardous landfill (general solid waste).

BOTTOM ASH

The construction sector in Australia is capable of becoming a significant consumer of “non-renewable materials”, and the increased use of bottom ash presents an opportunity for the industry to adopt a more circular approach in line with the federal government’s net-zero emissions target.

By processing bottom ash from non-recyclable waste, we can recover essential secondary aggregates and ferrous/non-ferrous metals that would otherwise go to waste. This reduces reliance on virgin resources, minimises environmental impact, and decreases carbon emissions. Bottom Ash can constitute up to 20% of the incoming residual, making it a significant contributing factor in diverting waste from landfills and achieving improved resource recovery outcomes.

TAKEAWAYS FROM VEOLIA UK

The recycling of ash from energy from waste into construction materials like gravel has been a well-established practice in the United Kingdom for many years, regulated under the UK Standard Rules SR2012 No. 13. Studies show that more than half of the ash generated from energy from waste facilities across Europe is repurposed and used in the construction industry.

This widespread reuse of bottom ash, in compliance with the UK environmental permitting regulations, highlights its value as a sustainable resource and helps reduce the need for new raw materials in construction projects, supporting a more circular economy.

Internationally, various beneficial reuse options have been identified for bottom ash aggregate, including:

• Road base and structural platform construction: it can be utilised as a durable and cost-effective base material for road construction and structural platforms.
• Pipe bedding and drainage material: its properties make it suitable for use as a bedding and drainage material for pipe installations.
• Aggregate in concrete or bitumen mixes: it can be incorporated as an aggregate component in the production of concrete or bituminous mixes for construction applications.
• Brick/paver production: it can be used as a raw material in the manufacturing of bricks and pavers, contributing to the circular economy and reducing the demand for virgin resources.

We can already see this in action globally at some of Veolia’s facilities in the UK and Belgium where we take bottom ash from residual mixed waste and process it into secondary aggregates for various construction projects. The material is processed through magnetic separation devices, including overband magnets and eddy current separators, to extract the metals. Metals can be recycled through specific mechanical treatment.

What remains is sampled and graded for its suitability in construction applications. Our UK facility expects to supply around 50,000 tonnes per year of this material.

Recycling bottom ash in this fashion presents many environmental benefits: 

• It avoids landfilling; 
• It reduces the carbon footprint of waste management by producing a valuable secondary aggregate locally;
• It has many useful applications because of its good mechanical properties, such as cement bound materials, utility trench backfill, a capping layer for site development, road base in road construction, structure filling and temporary piling mats.

THE MARYVALE EFW PROJECT

In a major step towards Australia’s progress for a truly circular economy, EPA Victoria approved the development of the state's first $8 million Bottom Ash Recycling facility in 2022. The innovative facility, part of the Maryvale Energy from Waste (EfW) plant, will efficiently and safely process bottom ash, recovering metals for recycling and producing an inert recycled aggregate suitable for use in road construction as a sustainable alternative to traditional asphalt. By allowing approximately 60,000 tonnes of aggregates and 6,000 tonnes of metals to be recycled annually, the facility strengthens the environmental credentials and circular economy alignment of the Maryvale EfW project.

AIR POLLUTION CONTROL RESIDUE (APCr)

Technology also exists to ensure  better resource recovery and sustainability outcomes by using APCr (known as ‘fly ash’) - which is created during the combustion process - to safely and permanently lock away any contaminants, while transforming it into a valuable resource.

APCr is a byproduct generated during the energy-from-waste combustion process. These residues contain fine particulate matter and contaminants, such as heavy metals and dioxins, that are captured and filtered out of the combustion gases before being released through the stack.

The stabilisation of APCr involves techniques that immobilise and encapsulate the contaminants. Additionally, innovative technologies exist to ensure better resource recovery and sustainability outcomes by using APCr to safely and permanently lock away any contaminants while transforming it into a valuable resource.

While the management and disposal of APCr must adhere to stringent environmental regulations and best practices, the exploration of beneficial reuse opportunities through advanced treatment technologies offers promising avenues for resource recovery and circular economy principles. However, any such applications must undergo rigorous testing and meet all relevant safety and performance standards before implementation.

SUMMARY

Globally, Veolia has experience in the design, build and financing of new energy from waste facilities, as well as the associated technology. With our commitment to a more circular economy, and the preservation of resources wherever possible,  supporting the introduction of best practice energy from waste facilities into the Australian market has been a strategic focus for our business.

As part of our operations, we maintain key global performance targets to ensure all of our assets are regularly maintained and as necessary, replaced, adhering to the highest standards for health, safety and environmental management.

We want to ensure the best environmental outcomes, so we recover as much value from these materials as possible.