Optimization of UV-C pulsed radiation strategy for a high-efficiency portable water sterilizer

In many places of the world, the lack of municipal facilities for water sanitation and purification makes self-treatment at a familiar scale, the only realistic solution to ensure continuous access to drinking water. In this context, UV disinfection treatment is a portable and efficient alternative to conventional methods, however, its power need is hindering its implementation in remote off-grid households. This work presents a portable water sterilizer device using UV-C LEDs, conceived for its direct implementation in isolated rural communities. Pulsed radiation operation has been studied as strategy to reduce the device energy demand. Most relevant parameters affecting the device operation and performance, namely voltage, radiation time, frequency and duty cycle; are thoroughly studied using the Design of Experiments methodology to optimize energy consumption and Escherichia coli removal from polluted water. The optimal conditions, found for pulsed radiation, showed a noteworthy reduction of 68 % of the energy consumption while improving the sterilization effectiveness, compared with continuous radiation. Furthermore, the efficiency of sterilization of the optimized prototype was benchmarked against a commercial device using river water samples. The presented prototype achieved higher E. coli disinfection effectiveness using a fraction of the energy consumption. All in all, the presented water sterilization device is an example of a technological improvement which uses energy efficiency as key developing driver while achieving performance requirements. Thus, contributing to the creation of affordable and efficient technological solutions to promote global access to drinking water.