As the global community begins to grapple with the transition to a circular economy, it’s important that the energy industry, which has a central role to play in the transition, is involved with helping develop solutions to enable this move. In Tarago Australia, the local community are benefiting from the Woodlawn Bioreactor – a unique facility designed to recover waste resources from putrescible waste in NSW, and effectively turns this into clean energy in the form of biogas.
The Woodlawn Bioreactor is one of the largest purpose-built landfill projects in the world. What was previously a copper, lead and zinc open-cut mine is now filled with putrescible waste diverted from other NSW landfill facilities, including 20 per cent of Sydney’s total putrescible waste.
This waste is then managed using advanced methods that significantly reduce the level of methane emissions released into the atmosphere.
The bioreactor generates electricity by harnessing methane gas, which is created by the decomposing waste, generating useful biogas.
This biogas powers generators producing enough electricity to supply over 10,000 households with power, and at present, the facility is capable of managing consistent rates of waste infilling until the year 2047 at a minimum.
The electricity produced at the conclusion of the filling will supply well in excess of 30,000 homes.
Dealing with waste
Waste is an ongoing issue for local, regional and state authorities in Australia, particularly when it comes to reducing landfill waste in conventional facilities. Operations such as the Woodlawn Bioreactor play a key role in diverting domestic waste from a typical landfill operation and turning it into a sustainable source of energy.
While the Bioreactor became operational in 2004, the technology that powers it is still considered cutting edge in terms of clean energy production for existing waste management facilities.
For each megawatt (MW) of power that the Woodlawn Bioreactor produces, an estimated 0.75 tonnes of physical waste is recycled, meaning that for every tonne of waste deposited at the facility, 1.33MW of clean electricity is produced.
Not only can this be used to power the facility, but also homes and businesses that are connected to the grid.
By dealing with waste and generating clean energy, the Woodlawn facility is meeting its objectives of creating a clean source of energy and recovering resources that would otherwise go unused to create a circular economy.
This is made possible by the many clean energy assets at the facility, including a solar farm and a wind farm. Further, Veolia is undertaking new technology trials at Woodlawn, and has carbon credits which can be purchased through the facility.
The facility’s methods of harnessing energy have changed and developed over the 15 years that it has been operating, with new and improved technology creating exciting opportunities for clean energy generation.
“In the bioreactor, in recent years the site completely re-thought the way we go about extracting our gas,” said Henry Gundry, Woodlawn Eco-Precinct Manager at Veolia.
“We now use a much more collaborative network of pipes focusing on extracting the biogas as it’s being produced. The site has invested heavily in purpose gas extraction systems to minimise the effects of waste settlement to ensure the longevity of the infrastructure.
This has enabled the site to increase its power generation capacity from 1MW in 2008 to the current 7MW in 2019. Exciting times for the power generation business as it looks to expand to 8MW in 2020.
“Over at the power station we’ve invested in gas conditioning units to improve the reliability of the engines and reduce maintenance costs”
“And when it comes to resource recovery, we’ve invested heavily in a mechanical and biological treatment facility that can recover ferrous material out of the waste stream and recover the organic portion as well, meaning we’re able to better work with the materials we do have, which helps to contribute to our circular economy goals.”
This mechanical and biological treatment facility (MBT) was opened in October 2017, after ten years of planning and trials at the Woodlawn Bioreactor site.
Using new technology to separate organics from mixed household waste, the facility is a key component of Veolia’s goal to capture methane with the landfill bioreactor and produce renewable energy.
The $100 million plant took almost two years to construct. As Veolia’s largest MBT in the world, it is capable of processing up to 240,000 tonnes of putrescible waste into organic material annually.
The plant recycles metals, diverting approximately 55 per cent of general waste from landfill. Compost is generated and used to remediate the degraded mine-site, while also reducing carbon emissions and meeting both Australian and NSW Environmental Protection Authority (EPA) standards.
The Woodlawn site also features a 2.5MW solar farm and a wind farm.
The Woodlawn Wind Farm has been operating at the site of the Woodlawn Bioreactor since 2011. Consisting of 23 individual 2.1MW turbines with an installed capacity of 48.3MW, the wind farm produces enough energy to power approximately 32,000 average Australian households each year.
This also represents a saving of approximately 138,000 tonnes of greenhouse gases a year, helping the facility to meet its circular economy objectives and continue to champion sustainability.
The solar element of the site involves a ground mount solar system with NEXTracker single-axis tracker panel technology, which directs solar panels towards sunlight throughout the day to maximise solar energy generation.
The solar farm is a 2.4MW facility, with sun tracker system and 7200 solar PV modules installed to provide energy to the bio-waste reactor at MBT.
“This facility has been running since July 2019, and it’s been a fantastic initiative to offset our electricity usage on site. By offsetting costs and minimising our emissions, it’s been a great inclusion,” said Mr Gundry.
The facility’s future
If the past 15 years of planning and development are anything to go by, the Woodlawn Eco-precinct an expect to see many more technological innovations and environmentally friendly objectives achieved in the coming years.
In early 2019, Veolia sought approval to construct and operate a Solid Recovered Fuel (SRF) facility at the Woodlawn site, which will have a capacity of 50,000 tonnes per annum.
If approved, this $12 million project would divert 37,400 tonnes of residual waste generated at the MBT from landfill, producing SRF material that would be used for energy recovery facilities off-site. It would also generate 25 construction jobs and three new operational roles.
As technology continues to develop and evolve, the Woodlawn facility will continue to look at opportunities to expand and support circular economy initiatives in NSW.
“Looking ahead, we’re very keen on expanding our resource recovery objective, harnessing waste heat and waste CO2, and we’ve got our on-site aquaculture farm which is capturing heat from our landfill biogas engines and we see a real potential avenue to take that forward and use that in food production,” said Mr Gundry.
“They’re big visions, and we’d really love to bring some of them to fruition in the years to come.”