The City of Johannesburg (CoJ), in collaboration with the Scaling Urban Nature-based Solutions for Climate Adaptation in sub-Saharan Africa (Suncasa) project and its partners, has unveilved a new nature-based eco-filter system aimed at improving water quality in the Juksei river.

Installed in the upper Jukskei river catchment, the eco-filter system will help address persistent water pollution challenges in the river, including mocrobial contamination, excess nutrients, organic waste and heavy metals.

The CoJ notes that this system provides accurate monitoring data, demonstrating the potential of the system to improve water quality, while supporting the irrigation of women-led community gardens at the Victoria Yards precinct in Johannesburg’s inner city.

Designed to function like a natural wetland, this eco-filter system enables continuous water quality monitoring to generate long-term datasets to assess performance and inform evidence-based decisionmaking.

The CoJ adds that this data will help document progress – highlighting both successes and ongoing challenges in catchment management, while supporting learning and replication in other parts of Johannesburg and across sub-Saharan Africa.

“The city is transitioning from reactive approaches to proactive, innovative solutions that restore the health of our urban rivers. The eco-filter system marks a significant step in integrating nature-based solutions with smart monitoring technologies.

“We view this as a scalable model for strengthening urban water resilience, aligned with our broader goals of ecological restoration, climate adaptation and sustainable service delivery,” says CoJ water management and biodiversity director Daniel Masemola.

The eco-filter consists of modular 800 ℓ units arranged in a series of ecological treatment cells, supporting both anaerobic and aerobic processes for water purification. While its primary function is to support biophysical monitoring of the Jukskei river, it also delivers tangible benefits to the local community by supplying water for the irrigation of community gardens in the area.

The eco-filter system was developed through a collaboration between ecological engineering consultancy Isidima Design and Development, non-profit organisation Water for the Future, engineering advisory company Zutari and the University of Johannesburg.

Independent think tank the International Institute for Sustainable Development and Suncasa bioremediation lead Richard Grosshans notes that this eco-filter system offers an innovative approach to improving water quality.

“Although the system is not designed to make the Juksei river potable or resolve catchment-wide pollution on its own, it serves as a visible and monitored bioremediation solution that reduces pollution loads and demonstrates the value of integrated green infrastructure. This model has strong potential for replication in other cities,” Grosshans says.