Design of an <b>A</b>utomatic <b>G</b>ray<b>W</b>ater <b>R</b>euse <b>M</b>anagement <b>S</b>ystem (A.G.W.R.M.S)

This project report presents the design of an automatic graywater reuse management system tailored for Ugandan households to mitigate the pressing issue of freshwater scarcity. The system integrates advanced electrical and mechanical components to autonomously collect, treat, and redistribute graywater generated from domestic sources such as sinks, showers, and laundry.

The report begins with a comprehensive review of global and regional water recycling practices, emphasizing Uganda’s gradual shift towards water reuse as a response to water scarcity, urbanization, and population growth. The project’s primary objective was to develop a solar-powered, cost-effective, and autonomous graywater recycling unit. Specific goals included the CAD-based design of the system, the development of a solar power sizing model, and the performance optimization of the prototype.

The system employs a combination of sensors (pH, turbidity, flow rate, and water level), solenoid valves, microcontrollers (Arduino Mega), and brushless DC pumps to facilitate automated water treatment and monitoring. Additionally, the solar energy subsystem comprising PV panels, battery storage, and an inverter was sized and simulated using MATLAB Simulink to ensure uninterrupted operation. Extensive mathematical modeling was conducted to analyze the energy consumption of individual components, the relationship between water quality parameters and power usage, and overall system efficiency. Flow simulations and automation behavior were modeled in MATLAB to validate the logical sequence of operations and quantify energy requirements. The system demonstrated potential for 185.13 Wh/day energy use, prompting the integration of a 50W solar panel and a 24Ah battery to meet daily demand.

This graywater management solution supports non-potable reuse applications such as irrigation and toilet flushing. Its design leverages locally available materials and scalable technology, making it feasible for deployment in resource-constrained environments. Ultimately, the system contributes to water conservation, lowers utility costs, and promotes sustainable urban development in Uganda.