Puresense RO system: a decentralized brackish water treatment framework for coastal communities

Indonesia has deployed numerous government-funded brackish water reverse osmosis (BWRO) and seawater reverse osmosis (SWRO) installations in coastal regions; however, many units fail to operate sustainably due to limited technical capacity, complex maintenance requirements, and the absence of reliable sensing and monitoring systems. Addressing this operational gap, this study develops and evaluates a low-complexity decentralized BWRO–SWRO system equipped with a simplified IoT-based monitoring module designed for stable operation in remote coastal settings. The prototype integrates STM32 control, ADS1115 high-resolution analog acquisition, and ESP-07 telemetry to monitor TDS, pH, temperature, and pressure with minimal sensor load. Testing was conducted using four feedwater sources with different salinity profiles. Results show permeate TDS consistently within 15–45 mg/L, rejection rates of 96–98%, operational pressure stability at 110–120 psi, and recovery ranging from 9–16% depending on feed characteristics. These findings demonstrate that a decentralized RO configuration with simplified instrumentation can deliver high-quality permeate while reducing failure points, operator burden, and maintenance complexity. This work provides a practical engineering approach to improving the reliability and sustainability of small-scale desalination systems in coastal communities.