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

What the report says

A Conversation Africa analysis published by AllAfrica says researchers in Franschhoek, about 75 kilometres east of Cape Town, have been testing a nature-based system to clean heavily polluted water from the Stiebeuel River. The river is affected by sewage and contaminated runoff linked to inadequate sanitation and drainage in the nearby Langrug informal settlement, where about 26,000 people live.

The work is being led through the Water Hub, a research site at a disused wastewater treatment plant associated with the University of Cape Town’s Future Water Institute. The team converted old sludge-drying beds into filter beds filled with stones, biochar and coarse sand. Water from the river is pumped through the system without chemical treatment and, after several days, is described as clean enough for irrigation.

According to the article, the system has consistently removed E. coli and reduced ammonia and phosphorus substantially, while also helping to cut some pharmaceutical compounds and microplastics. About 50,000 litres of contaminated water are treated each day, with roughly 3,000 litres reused to irrigate vegetable gardens run by young women from the settlement. The rest is returned to the river.

The piece argues that such decentralised, low-energy treatment could help municipalities facing weak infrastructure, higher electricity costs and limited technical capacity. It also presents the project as an example of how wastewater can be reused locally to support food gardens, livelihoods and water security.