Development of a low-cost waste water treatment and recycling unit at car wash stations in Uganda.

Abstract

Car washing has been identified as a major consumer of water and generator of waste water, leading to environmental pollution and increased expenditure on fresh water. However, this issue has not received much attention in Uganda. The study examines the development of a low-cost waste water treatment and recycling unit for Uganda’s car wash industry to address water conservation and pollution mitigation challenges. A quasi-experimental design was used to study 10 car wash stations in Kampala, with a focus on analyzing waste water pollutants such as Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), Total Dissolved Solids (TDS), turbidity, oil and grease, and detergents. A prototype treatment system, utilizing a sandgravel-charcoal filter, was tested to determine its effectiveness in reducing contaminants to meet National Environment Management Authority (NEMA) standards. Results demonstrated significant reductions in TSS, oil, grease, and COD, supporting the system's suitability for reusing treated water within car wash operations. Economic analysis projected a positive Net Present Value (NPV) of approximately 11 million Ugandan shillings over three years, indicating financial viability for car wash operators. The system’s affordability, simplicity, and scalability make it a promising solution for small-scale car wash businesses and potentially other waterintensive industries. Key recommendations include government support for eco-friendly technologies, industry implementation of water recycling practices, and further research into alternative local filtration materials and system automation to enhance pollutant removal and user-friendliness