In partnership with RMIT University, Intelligent Water Networks (IWN) and Greater Western Water, South East Water is helping to prove PYROCO, an RMIT innovation, that has improved the efficiency of biochar production. Biosolids are a by-product of wastewater treatment and once converted into biochar, is a valuable resource for industry, particularly agriculture. The unique pyrolysis technology is a game changer for industry across the globe.
The challenges biosolids pose to industry
As a wholly owned subsidiary of South East Water, Iota is supporting commercialisation of solutions by the utility’s research and development arm.
Eamon Casey, Technical Director at Iota, explained how water authorities are acting to strengthen the circular economy while protecting the environment from the impacts of microcontaminants.
“Most treatment facilities manage sludge waste through drying, stockpiling and transporting to be used for land spreading. A deepening understanding of the impacts of microcontaminants on the environment has driven water authorities to look for alternatives,” said Casey.
“Water authorities in Australia, the UK, the EU, and parts of the US have the same challenge. They must be conscious of the environmental implications of perfluoroalkyl and polyfluoroalkyl substances, microplastics and other emerging contaminants and they are looking for an alternative,” said Casey.
RMIT has worked with South East Water over the last five years to develop a more efficient pyrolysis approach with low energy requirements. PYROCO offers water authorities a carbon positive approach for managing biosolid waste.
PYROCO a game changer for industry
IWN represents the interests of the Victorian water industry. In mid-2021, South East Water, Greater Western Water and IWN operated a PYROCO pilot plant with a capacity of 1 tonne per day.
RMIT developed PYROCO, an innovative efficient reactor, the first of its kind in Australia.
PYROCO has a number of benefits that differentiate the technology from other reactor systems. One of the game changers is that it’s very efficient at converting organic material into high-quality biochar.
PYROCO is highly energy efficient. As utilities seek to achieve climate neutral footprints, the technology facilitates carbon sequestration, enabling utilities to operate beyond carbon neutral, into carbon negative, including the opportunity for carbon offsets.
“Gases and biosolids meet within the reactor on a fluidised bed at 600-700 degrees Celsius, and the biosolids become biochar in milliseconds. Gases discharging through the top of the reactor are reused,” said Casey.” We can produce enough biochar without needing external energy beyond the pilot light,” said Casey.
Contaminants in biosolids including PFAS and microplastics are a problem reducing the option for conventional land spreading. The PYROCO pilot plant produces biochar with no detectible PFAS.
There is also a reduction in waste volume, a diversion of waste from landfill, and reductions in the transport cost and emissions associated with land spreading.
The process delivers a high value biochar suitable for a variety of industrial applications beyond traditional agricultural use.
The PYROCO plant is highly portable given its modularised design and small footprint. This is especially advantageous for regional water authorities with smaller stockpiles, as it is more efficient to move the plant rather than the stockpile, from site to site.
“The disposal of biosolids is a challenge across the water industry. South East Water is continually looking for ways we can work with others to create innovative solutions to protect our environment and help our customers and community. This technology is scalable, a key benefit of the solution for urban and regional water utilities,” said South East Water’s Managing Director, Lara Olsen.
Australia’s future biochar landscape
South East Water Senior Research Scientist and Centre Deputy Director (Industry) for the Australian Research Council Training Centre for the Transformation of Australia’s Biosolids Resource, Aravind Surapaneni has been working on this technology for years. His work on feedstock for pyrolysis, the organic inputs into pyrolysis including food waste and garden waste from compost screening, is key to the development of optimal biochar.
PYROCO is unique in that it can accommodate varied feedstocks such as organics or outputs from agriculture. That will make it attractive for regional organic networks.
“If you understand your feedstock, you can make the right biochar. We spent three and a half years working towards a pilot plant at Greater Western Water’s Melton Recycled Water Plant in Melbourne,” said Surapaneni.
“We thank Greater Western Water for getting involved and providing their Melton site. We successfully demonstrated the technology and are now building a commercial demonstration plant. It’s scheduled to be ready by the end of 2023.”
Innovative technology brings with it economic opportunities as well. “It is an Australian homegrown technology,” Surapaneni said.
“This emerging thermal technology space is new for the water industry. The next generation of chemical engineers will need training in new techniques and methodologies. Biochar is the next important development for the water industry in Australia, North America, and Europe.”
He commented that there would be opportunities for the industry to expand as more market segments learn about the benefits of biochar. Currently, Australia is a net importer of biochar.
South East Water’s Research and Development Manager, David Bergmann agrees. He talked about the different grades of biochar.
“The biochar we are creating through pyrolysis has an incredible pore structure. It has capacity to hold things within that structure,” he said. “We know it contains nitrogen, phosphorus, nutrients, and trace elements useful for agriculture.”
While the ability to create biochar’s suited for different industries is an opportunity, Bergmann is also looking at activated carbon. Biochar can be manufactured into activated carbon where there is a potential opportunity for use in filtration applications
“Early research suggests Biochar has potential use as a binding agent in road base and as a cement replacement. We believe that a road base adhesive is a viable short-term solution. If we were to create high carbon biochar, there are additional use cases in sodium-ion batteries,” said Casey.
Bergmann added that a natural by-product is hydrogen, which has a high value.
Where to from here?
South East Water and Iota are building a larger scale PYROCO plant designed to process up to 3,000 tonnes of biosolids a year, producing approximately 500 tonnes of biochar.
Iota, a wholly owned subsidiary of South East Water, is excited by the technology and is uniquely placed to support South East Water to realise PYROCO’s value for industry.