Experts at the CSIR have contributed to a new book highlighting the potential of constructed wetlands as sustainable nature-based solutions. The publication, titled, “Constructed Wetland Technology as a Nature-Based Solution for Sustainable Municipal Wastewater Treatment in the Western Indian Ocean region”, showcases the role of these systems in improving water quality along the region’s coasts.
Launched during the Western Indian Ocean Marine Science Association (WIOMSA) Symposium in Kenya from 28 September to 3 October 2025, the book was compiled by lead author and editor Richard Joseph Kimwaga from the University of Dar es Salaam, with contributions from the Nairobi Convention, University of Dodoma and the CSIR.
A major scientific contribution came from the CSIR, whose experts co-authored the first chapter on coastal and marine pollution in the Western Indian Ocean (WIO) region. The chapter was written by CSIR principal researchers Prof. Susan Taljaard, Steven Weerts and Dr Brent Newman, together with Sumaiya Arabi from the Department of Forestry, Fisheries and the Environment. The opening chapter establishes the scientific and policy context for managing coastal waters, underscoring why nature-based solutions, such as constructed wetlands, are essential for addressing escalating pollution pressures on coastal and marine ecosystems.
The CSIR-led team provides a comprehensive overview of the extent, magnitude and nature of coastal and marine pollution in the WIO region. Their analysis links pollution patterns to hydrographic features, ecosystem distribution, dominant pollution sources and the impacts of contaminants on ecological integrity and human health.
Their findings show that sectors directly contributing to coastal and marine pollution include urban development, tourism, agriculture, forestry, fisheries, aquaculture, industry, mining, marine transport and energy production. “Key problems stemming from pollution include microbiological contamination, nutrient enrichment, marine litter (including plastics) and suspended sediment loading,” says Taljaard.
Weerts emphasises the scale of the challenge: “The region’s combined coastline stretches close to 20 000 km across Somalia, Kenya, Tanzania, Mozambique, South Africa, Madagascar, Comoros, Réunion, Mauritius and Seychelles. All these countries are experiencing rapid urbanisation and population growth along their coastal zones.” These dynamics, the experts show, have intensified pollution linked to inappropriate disposal of municipal wastewater, contaminated urban and agricultural runoff, livestock operations and industrial effluents.
Newman notes the practical importance of the publication: “This book is critical for learning from real-world scenarios and can guide efforts to minimise the impacts of microbiological and nutrient contamination in aquatic environments. Many human diseases in coastal areas are water-borne and directly associated with poor water quality.”
Across its 10 chapters, the book presents regional insights into the design, function, operation and maintenance of constructed wetlands, explaining how these green technologies remove pollutants and offer scalable, affordable wastewater treatment options. Although not a formal design manual, the book distils nearly 30 years of evidence-based experience with constructed wetlands in the WIO region.
“It is a resource built on decades of technical data and practical innovation, using the latest approaches and concepts,” says Weerts. “The scientific and technical stories shared provide valuable insights into municipal wastewater treatment experiences across the region.”
The publication underscores the CSIR’s long-standing role as a key scientific partner in advancing sustainable, nature-based wastewater solutions for the WIO region – a contribution that continues to shape policy, practice and future innovation.
