Two unrelated waste problems have been building up in parallel in different parts of the same broader industry. Every year, wastewater treatment plants worldwide generate millions of tonnes of biosolids and about 30% of this material ends up in stockpiles or landfills because there are not enough beneficial uses for it. In the meantime, brick manufacturers worldwide extract more than 3 billion cubic meters of clay soil to produce about 1.5 trillion bricks each year, a figure that rises with construction demand. In 2019, researchers at RMIT University in Melbourne decided to explore the connection between these two issues by producing fired‑clay bricks out of sewage sludge, as described in the university’s 2019 news release on recycling biosolids into sustainable bricks.
Mixing biosolids into clay cut the energy needed to fire bricks by nearly half
