Design and Modeling of a Solar-Powered Water System for Real-Time Microbial Detection and Treatment

Abstract

<ns5:p> Background Access to safe drinking water remains a persistent challenge in low-resource settings such as Ishaka Municipality, Uganda, where surface and groundwater sources are frequently contaminated and access to reliable electricity is limited. This study presents the design, modeling, and performance evaluation of a solar-powered hybrid water treatment system integrated with a biosensor-based microbial detection unit, enabling autonomous operation and real-time water quality monitoring for decentralized applications. Methods A total of 384 water samples were collected from springs, wetlands, wells, and tap sources and analyzed for key physicochemical and microbial parameters, including turbidity, pH, and indicator organisms. The proposed system integrates sedimentation, activated carbon filtration, reverse osmosis, and solar thermal disinfection to achieve multi-barrier treatment. Hydraulic and filtration performance were modeled using fluid flow and porous media principles, while microbial inactivation was described using first-order kinetic models. The photovoltaic subsystem was evaluated through detailed loss modeling, incorporating temperature effects, partial shading, and inverter inefficiencies to assess overall system reliability. Results Baseline results indicated significant contamination, with <ns5:italic>Escherichia coli</ns5:italic> concentrations reaching 210 CFU/100 mL and turbidity values up to 146 NTU. The hybrid system achieved over 95% removal of contaminants, complete elimination of <ns5:italic>E. coli</ns5:italic> , and compliance with World Health Organization drinking water standards. Solar thermal disinfection provided a 4–6 log reduction in microbial indicators. The integrated biosensor demonstrated rapid response times (45–90 seconds) and strong correlation with laboratory biochemical oxygen demand measurements (R <ns5:sup>2</ns5:sup> = 0.89–0.94). The photovoltaic subsystem maintained a performance ratio of 0.84–0.88, consistently meeting 100% of operational energy demand under varying environmental conditions. Conclusion These results demonstrate that the proposed system provides an effective, energy-autonomous solution for decentralized water purification with real-time monitoring capability, offering significant potential for improving access to safe drinking water in rural and resource-limited environments. </ns5:p>