Nature-based solutions for sustainable wastewater reuse: treatment wetlands for irrigation at Ndiebene Gandiol School, Senegal

ABSTRACT Access to safe sanitation and wastewater reuse in rural Sub-Saharan Africa remains a critical challenge, impacting both public health and socio-economic development. This study presents the implementation of a decentralized treatment system using constructed wetlands with Typha and Vetiver plants for wastewater treatment and irrigation reuse at Ndiebene Gandiol School in Senegal. The treatment system comprises a septic tank followed by two horizontal subsurface flow wetlands. Over ten months of monitoring, the system demonstrated high pollutant removal efficiency, achieving over 90% reduction in Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD5), and Suspended Solids (SS). Additionally, fecal coliform levels were reduced to below 200 CFU/100 mL, and helminth eggs were completely eliminated. The treated effluent meets World Health Organization guidelines for restricted irrigation, ensuring safe and sustainable water reuse. The project emphasizes the use of locally sourced materials and strong community engagement, promoting long-term operational sustainability in resource-limited settings. Beyond improving sanitation, it enhances school environments by creating green spaces and supporting sustainable water management practices. This initiative provides a scalable and cost-effective model for decentralized sanitation, with significant potential for replication in other rural schools across the Sahel region.