Researchers at the University of Stuttgart, Germany, have developed a new eco-friendly building material: bio-concrete made from human urine. Using a process called biomineralisation, bacteria mixed with sand are flushed with calcium-rich urine, solidifying the mix into a durable concrete alternative. The material, tested under the “SimBioZe” project, could cut emissions and water use compared to conventional cement. Early samples have shown promising strength, with lab tests ongoing to improve performance using real human waste. The method aims to enable a circular value chain, turning wastewater into both construction material and fertiliser. A pilot project is planned at Stuttgart Airport, where researchers will process collected urine into usable products. Currently in the second phase focusing on optimisation and real-world testing. The innovation could reshape sustainable construction.