The use of a solar simulator device to standardize microbiological decontamination of contaminated water by solar disinfection by the SODIS and MB/SODIS protocols

Abstract

AbstractConsuming microbiologically‐contaminated water is the primary cause of many water‐borne diseases and deaths worldwide. Governments aim at providing drinking water for vulnerable populations, especially through low‐cost interventions. Therefore, the solar disinfection (SODIS) of such pathogens provides a simple and cost‐effective way to obtain good quality water. In this procedure, PET bottles are filled with contaminated water and exposed to sunlight for 1–2 days. To accelerate decontamination, methylene blue (MB) dye added as a photocatalyst, boosts singlet oxygen generation upon absorbing red‐band sunlight. This study explores the use of a Sunlight Simulator (SSL) device to research and standardize the SODIS method with a vital dye as MB. PET bottles were filled with artificially‐contaminated water with Streptococcus epidermidis and Deinococcus radiodurans Gram‐positive bacteria, Escherichia coli and Salmonella typhimurium Gram‐negative bacteria, or bacteriophage λ as well. In all experiments, 50 ng/mL MB ensued a synergistic lethal effect after SSL exposure. The results indicate that bacterial and bacteriophage inactivation can be achieved in shorter times with MB‐SSL treatment compared to SSL without MB. In this sense, when compared to previous sunlight‐SODIS results, the SSL source is a reliable tool to study the parameters of both SODIS and MB‐SODIS protocols, and also a feasible tool to afford assays whenever there are unfavorable climate conditions.