There have been a number of eco trends in the housing industry lately from net-zero homes to smart homes and using recycled materials.
But the latest creation of turning biosolids into brick could (not literally) be on the nose with a university team developing a way to recycle the world’s stockpiles of treated sewage sludge and boost sustainability in the construction industry.
Biosolids are a by-product of the wastewater treatment process that can be used as fertiliser, in land rehabilitation or as a construction material.
According to lead investigator associate professor Abbas Mohajerani, from RMIT University, around 30 per cent of the world’s biosolids are stockpiled or sent to landfill, using up valuable land and potentially emitting greenhouse gases, creating an environmental challenge.
Now a team at RMIT University has demonstrated that fired-clay bricks incorporating biosolids could be a sustainable solution for both the wastewater treatment and brickmaking industries.
Published recently in the journal Buildings, the research showed how making biosolids bricks only required around half the energy of conventional bricks.
“As well as being cheaper to produce, the biosolids bricks also had a lower thermal conductivity, transferring less heat to potentially give buildings higher environmental performance,” said professor Mohajerani.
The EU produces over 9 million tonnes of biosolids a year, while the United States produces about 7.1 million tonnes. In Australia, 327,000 tonnes of biosolids are produced annually.
“The study found there was a significant opportunity to create a new beneficial reuse market - bricks,” he said.
“About five million tonnes of the biosolids produced in Australia, New Zealand, the EU, US and Canada currently go to landfill or stockpiles each year. Using a minimum 15 percent biosolids content in 15 percent of bricks produced could use up this five million tonnes.”
Professor Mohajerani said the research sought to tackle two environmental issues – the stockpiles of biosolids and the excavation of soil required for brick production.
“More than three billion cubic metres of clay soil is dug up each year for the global brickmaking industry, to produce about 1.5 trillion bricks,” professor Mohajerani, a civil engineer in RMIT’s School of Engineering, said.
“Using biosolids in bricks could be the solution to these big environmental challenges. It’s a practical and sustainable proposal for recycling the biosolids currently stockpiled.”
Biosolids can have different chemical characteristics, so the researchers recommended further testing before production.