Technology assessment of solar disinfection for drinking water treatment

Poor access to safe drinking water is a major sustainability issue for a third of the world’s population, especially for those living in rural areas. Solar disinfection could be the choice of technology considering the abundant sunlight exposure in infrastructure-limited regions. However, despite recent technological advances, it remains unclear which solar disinfection option is more broadly applicable and reliable, enabling the most efficient use of solar radiation. Here we examine the potential of five most typical solar-based, point-of-use water disinfection technologies, including semiconductor photocatalysis to produce hydroxyl radical, dye photosensitization to produce singlet oxygen, ultraviolet irradiation using light-emitting diodes powered by a photovoltaic panel, distillation using a solar still and solar pasteurization by raising the bulk water temperature to 75 °C. The sensitivity analysis allows us to assess how pathogen type, materials property, geographical variation in solar intensity and water-quality parameters interactively affect the effectiveness of these technologies under different scenarios. Revealed critical challenges point to the large gap between idealized materials properties and state of the art, the risk of focusing on select pathogens that show maximum inactivation effectiveness and the failure to consider uncertainties in water quality and geographical variations. Our analysis also suggests future pathways towards effective solar disinfection technology development and real-world implementation.