Optimizing solar disinfection: Cost-effective solutions with simple collectors

Abstract

Access to safe drinking water remains a critical global challenge, especially in low-income regions. Solar water disinfection (SODIS) offers a sustainable and low-cost treatment alternative, though its implementation is often limited by long exposure times and low treatment capacity. This study investigates the use of simple flat collectors (featuring one-, two-, or three-sided flat reflectors) as a cost-effective means to enhance SODIS performance, as compared with the widely used compound parabolic concentrators (CPC). Over 1300 collector configurations were evaluated using a ray tracing simulation tool, considering solar incidence, latitude (0°–50°), and varying cloud cover. The collectors were assessed under two criteria: yearly solar dose and yearly solar dose per unit of projected area. Results show that, under the first criterion, one-sided and two-sided flat collectors can surpass the performance of a standard CPC at higher latitudes, despite being much cheaper and easier to fabricate. Under the second criterion, all simple collectors outperform the CPC, highlighting their superior efficiency in terms of space usage. Experimental validation through actinometry and E. coli inactivation confirmed the simulated predictions. However, achieving such performance requires precise geometric design tailored to the target location. This study demonstrates the potential of well-designed, simple collectors to provide an affordable and efficient alternative for decentralized water disinfection.