Researchers at the University of Stuttgart have developed a novel cement-free bioconcrete using human urine. DPA Trends News has reported that the team’s recipe mixes sand and a bacterial powder in moulds, where it is rinsed with urine for a period of days. This converts the urine’s urea content into calcium carbonate crystals. This reportedly results in faster hardening than concrete produced using conventional cement, ending in a block with a compressive strength of 60MPa. This makes the resulting bioconcrete blocks suitable for use in load-bearing masonry or as paving materials. 26,000l of urine produced 1m³ of bioconcrete.

Toilet systems producers Arwinger and Kompotoi supported the research, with prospective partners for collaborations including Stuttgart Airport and local festivals in Baden-Württemberg.