Could our pee be used to create sustainable alternatives in the building industry? Scientists are testing the possibilities though they need hundreds of litres of urine for their experiments – and are calling on campers in Germany to spend a penny for their efforts. Stuttgart (dpa) – Concrete made from human urine may sound unusual but this is a research project at the University of Stuttgart. Campers at a travel fair have donated litres of their urine in a bid to help build more sustainable structures in future. Researchers at the University of Stuttgart are using their urine to develop a kind of concrete that does not require cement and should be significantly more climate-friendly. Donating not flushing "We build on urine" was what scientists wrote on a display at the CMT travel trade fair to promote donations. They asked campers to pour their urine into collection containers set up by the team led by Professor Lucio Blandini, head of the Institute of Lightweight Structures and Conceptual Design (ILEK). They gathered around 100 litres before the fair ended, says Blandini, thanking in particular some six or seven campers who regularly passed their urine. Nonetheless, the researchers had hoped for more – as urine is a key ingredient in the production of bioconcrete. Conventional concrete consists mainly of sand, water and cement as a binding agent – an adhesive whose production releases enormous amounts of climate-damaging CO2. Now, researchers in Stuttgart have therefore developed bio-concrete: Without cement, but using bacteria instead, in research backed by Arwinger and Kompotoi, two companies specializing in sustainable toilet systems. To make bioconcrete, you take sand with a bacteria-containing powder, fill it into moulds and rinse it with urine for days. The urea in the urine is converted into calcium carbonate crystals. That means the concrete hardens even faster than conventional cement, the scientists say. Industry has large carbon footprint How to reduce the CO2 footprint of concrete is a major concern for the industry. With a share of around 6% to 7% of global CO2 emissions, the global cement industry must "make its contribution to climate protection," says the German Cement Works Association (VDZ). The concrete industry is also looking at processes that could replace cement, says Ulrich Lotz, Managing Director of Betonverbände Baden-Württemberg. "Ecology only comes into play if it is at least economically equivalent, equally priced and perhaps even advantageous," he adds. Cement is the "cheapest adhesive in the world," he notes but the higher the CO2 tax, the more expensive cement becomes. The "charm" of bioconcrete from Stuttgart is the availability of the basic resources, he says. "They cost nothing in themselves." But "capturing" the urine in such quantities requires some infrastructure that is not in place at present. 26,000 litres of urine for 1 cubic metre The test specimens of the bioconcrete from Stuttgart can withstand a pressure of around 60 megapascals. In theory, this already allows initial applications such as concrete blocks for load-bearing masonry, columns or paving stones. In future, the scientists also want to produce components such as beams. However, in order to produce larger pieces of concrete, they need hundreds of litres of the human waste product. Extrapolated to one cubic metre of bioconcrete, the process requires around 26,000 litres of urine. Seeking new sources To obtain such quantities, the researchers are relying on cooperation partners, weighing Stuttgart Airport and festivals so far. They also want to find out what effect it has if there are also residues of medication, drugs or hormones in people's pee. So far, the tests have only been carried out with the urine of men who have donated wee to the institute. The fair visitors were very interested in the project, Blandini says, noting many grinned initially on hearing the words, "We want to build using urine." The following information is not intended for publication dpa kke ho evy xxde arw
(The article has been published through a syndicated feed. Except for the headline, the content has been published verbatim. Liability lies with original publisher.)
