Australia ranks among countries with the world’s highest per capita consumption of coffee, with over 1.3 million cups sold every day.
Researchers from Swinburne University of Technology have developed a method for creating bricks from used coffee grounds, which could dramatically reduce the carbon footprint of Australia’s construction industry.
Their project has reached a commercial milestone with an IP licensing deal with Green Brick to bring the product to market, with the support of Hampton Capital.
The low-emission bricks are made by blending used coffee waste from cafes and restaurants with clay, then adding an alkali activator.
Traditional brick manufacturing is energy-intensive and relies heavily on high-temperature kilns powered by fossil fuels.
The process being implemented by Swinburne’s researchers requires the bricks to be baked at temperatures below 400 degrees Celsius, 80 percent lower than traditional firing temperatures.
“It’s lighter on energy, faster to produce, and designed to reduce electricity-related CO₂ emissions by up to 80 percent per unit,” Dr Yat Wong, who led this project at Swinburne, says.
The research team claims that the bricks offer double the Australian minimum standard for strength too.
“For the last century, materials have been judged by one thing: cost per square metre, but in the next chapter, we’ll judge them by carbon, transparency, and circularity. And those metrics favour a whole new kind of product,” Green Brick’s founder Philip Ng says.
Repurposing coffee waste
YouGov data suggests that 66 percent of Australians are avid coffee drinkers, consuming the beverage daily or almost every day.
Australia reportedly generates approximately 75 million kilograms of ground coffee waste every year. Globally, 10 billion kilograms of spent coffee grounds are generated annually.
Most of the coffee ground waste ends up in landfills, where it emits methane, a greenhouse gas.
Two years ago, RMIT University said that its team developed a technique to make concrete 30 percent stronger by turning waste coffee grounds into biochar, using a low-energy process without oxygen at 350 degrees Celsius.
Last year, RMIT teamed up with Macedon Ranges Shire Council to conduct a world-first coffee concrete footpath trial.
Demonstrating its suitability for large-scale infrastructure projects, Major Road Projects Victoria (MRPV) and project contractor BildGroup last year used concrete mixed with biochar as a replacement for river sand in the Pakenham Roads Upgrade.
For that project, Earth Systems converted five tonnes of spent coffee grounds – about 140,000 coffees – into two tonnes of useable biochar, which has been laid into the 30-metre cubed footpath along McGregor Road in Pakenham.
Read more: Researchers convert low-grade clay into sustainable cement
