@article{Ekene Jude Nwankwo_Jonah Chukwuemeka Agunwamba_2021, title={Effect of reactor characteristics on the seasonal effectiveness of solar disinfection: a factorial study}, volume={47}, url={https://watersa.net/article/view/9451}, DOI={10.17159/wsa/2021.v47.i1.9451}, abstractNote={<p>Solar disinfection (SODIS) involves exposing water stored in transparent polyethylene terephthalate (PET) containers to the sun for about 6 h of strong sunlight, after which the water is rendered safe for consumption. This study investigated the seasonal effect of reactor characteristics on the inactivation kinetics/constant of faecal coliforms by conducting a 2<sup>3</sup> factorial experiment, involving two levels of PET bottle size, PET bottle thickness, and PET bottle rear surface, uniquely combined to form 8 SODIS reactors/experimental units. The faecal coliform population of hourly samples taken from the 8 SODIS reactors showed that the inactivation kinetics/constant depends on the irradiation energy and maximum water temperature as dictated by the reactor characteristics. The average rate constant of the reflective reactors (1.37 ± 0.43 h<sup>-1</sup>) was significantly better (<em>p</em> < 0.001) than the absorptive reactors (1.17 ± 0.59 h<sup>-1</sup>) between June and October. The average rate constant of the small PET bottles (1.73 ± 0.65 h<sup>-1</sup>) is significantly higher (<em>p</em> < 0.002) than the large PET bottles (1.46 ± 0.51 h<sup>-1</sup>) from December to May; while the average rate constant of the light PET bottles (1.58 ± 0.64 h<sup>-1</sup>) is significantly better (<em>p</em> < 0.001) than the thick PET bottles (1.41 ± 0.52 h<sup>-1</sup>) year-round. Analyses of results confirmed a two-way interaction effect between PET bottle size and PET bottle thickness and between PET bottle rear surface and PET bottle thickness for periods with average radiation intensity of  450–500 W∙m<sup>−2</sup>. Although container size and thickness were the most significant factors, combining light PET bottles with absorptive rear-surface could extend the applicability of SODIS to regions that fall short of the recommended radiation intensity threshold of 500 W∙m<sup>−2</sup> for 5 h.</p>}, number={1 January}, journal={Water SA}, author={Ekene Jude Nwankwo and Jonah Chukwuemeka Agunwamba}, year={2021}, month={Jan.} }