South Africa: This South African River Has a Bacteria Count Off the Charts - a Natural Filter Is Cleaning It for Watering Food Gardens

The Stiebeuel River in Franschhoek, South Africa, is facing severe pollution due to inadequate sanitation and drainage systems in the nearby Langrug informal settlement. Home to about 26,000 residents, the area struggles with ageing and overloaded infrastructure. The river, once a site for bathing, now serves as a dumping ground for waste and contains high levels of E. coli bacteria, ammonia, and phosphorus.

Researchers at the University of Cape Town's Future Water Institute and the Water Hub in Franschhoek are experimenting with nature-based water treatment systems to address this issue. They have repurposed old drying beds from a former wastewater treatment plant into filter beds filled with small stones, biochar, and coarse sand. These natural filters effectively remove pollutants from the river water, making it safe for irrigation purposes within five days.

After filtering, the water contains no E. coli bacteria and has seen an 85% to 95% reduction in ammonia and phosphorus levels. The treated water is then used to irrigate vegetable gardens managed by young women from the informal settlement, fostering skills development and small-scale enterprise opportunities. The remaining water is safely discharged back into the river.

This nature-based treatment system, which doesn't require electricity or expensive equipment, could be a valuable resource for municipalities facing challenges with rising electricity costs, deteriorating infrastructure, and limited technical skills. It also offers a local source of treated water for farming and other uses, particularly in areas affected by drought and climate change.