Deployment of the Nsu-Pa purification technique: a natural filtration and renewable energy approach using micro turbines

Abstract

Water pollution caused by illegal mining (galamsey) has severely impacted major rivers in Ghana such as the Pra, Ankobra, Birim, Densu, and Tano with toxic chemicals like mercury and cyanide contaminating water sources, farmlands, and aquatic ecosystems. As a result, nearly 60 % of the country's water bodies are polluted, forcing the Ghana Water Company Limited (GWCL) to shut down several treatment plants. This has led to serious health risks, economic hardship, and food insecurity, particularly affecting agriculture and cocoa production. This study presents the Nsu-Pa Purification Technique, an integrated system that combines natural filtration with renewable energy from micro turbines. The system uses the kinetic energy of flowing water to generate electricity that powers the purification process, which occurs in multiple stages. The primary treatment removes scum and sludge. The secondary treatment eliminates toxic substances such as lead, arsenic, and nitrate, significantly improving water quality. Aeration then introduces oxygen to promote bacterial treatment and water stabilization. A monitoring tank with turbidity and pH sensors ensures treated water meets safety standards. Results demonstrate a significant improvement: turbidity reduced from 100 NTU to 4 NTU, pH stabilized from 14 to 7.0, and contaminant reductions of 95 % for lead, 90 % for arsenic, and 85 % for nitrate. These outcomes emphasize the potential of renewable energy-driven purification in combating pollution and restoring clean water access. The proposed system is scalable, sustainable, and adaptable, providing a practical alternative to conventional water treatment methods for Ghana's mining-affected communities.