Determination and implementation of an onsite management system for motor-vehicle wash effluents: A field-scale commercial application toward sector sustainability

Abstract

The global upsurge of vehicle wash enterprises is allied to the production of large wastewater volumes. This effluent contains organic and inorganic compounds which can cause environmental pollution. Upscaling the laboratory-scale systems for motor-vehicle wash wastewater (MVWW) treatment to field-scale commercial application is essential for enabling the circular economy framework, meeting the United Nations' 2030 Agenda. In this study, 98 research publications on MVWW treatment technologies were scrutinized for bibliometric-meta analysis. After, a practical treatment option was identified and designed for implementation in a Ugandan motor-vehicle wash station and a comprehensive economic evaluation was performed. A continental outlook on MVWW quality showed that its major pollutants include oil-greasy compounds, surfactants, and suspended solids. Results showed that a hybrid system consisting of coagulation/flocculation/sedimentation and sand/gravel filtration was identified as the most practical treatment method for implementation in motor-vehicle washing stations. The final effluent of the field-scale integrated treatment system contained turbidity = 2 ± 0.0 NTU, chemical oxygen demand (COD) = 18.9 ± 0.6 mg/L, surfactants = 3.2 ± 0.3 mg/L, supporting onsite recyclability in motor-vehicle washing activities. The integrated system demonstrated a profitability scenario with a benefit-cost ratio (B/C) > 1 and a payback period of 2.7 years. Implementing the hybrid system for onsite MVWW treatment could fulfil targets of sustainable development goals related to; water conservation, water recycling and reuse, and environmental protection.