Every day, 50,000 litres of polluted water flow from South Africa's Stiebeuel River into natural filter beds, where stones, sand and biochar clean it in 5 days, removing 99% of harmful bacteria and creating water for irrigation

Researchers in South Africa are using a nature-based filtration system to treat polluted water from the Stiebeuel River in Franschhoek. At the Water Hub, old wastewater treatment infrastructure has been adapted with stones, coarse sand, biochar, plants and naturally occurring microbes to remove pollutants. The system treats approximately 50,000 litres of contaminated water each day, with the research reporting 99% removal of harmful bacteria and major reductions in ammonia and phosphate.