Solar disinfection (SODIS) is a simple and low-cost household water treatment (HWT) option used for disinfection of drinking water. In this study, the bacterial inactivation potential of SODIS was evaluated under the solar irradiance observed in different seasons in Bangladesh according to WHO evaluation protocol of HWT, and the SODIS experiments were conducted for both transmissive and reflective reactors using PET bottles and plastic bags. In summer, log reduction value (LRV) more than 5 was observed for the transmissive PET reactors for 6 to 8 hr exposure to sunlight and the treated water complied with the microbial standard of zero colony forming units/100 mL in drinking water. In monsoon and winter, LRV > 4 can be achieved for 16 hr and 8 hr exposure to sunlight, respectively, using reflective reactors. The plastic bag was found to be more effective than PET. A safe exposure time was estimated from the Weibull model to be maintained for SODIS application to achieve 4.0 LRV and also to prevent the re-growth of microorganisms in the treated water. A significant re-growth of microorganisms was observed in the treated water, thus SODIS with other HWT processes can be recommended for use in communities with an unsafe drinking water supply.

太阳能消毒（SODIS）是一种用于饮用水消毒的简单且低成本的家用水处理（HWT）选项。在这项研究中，根据WHO的HWT评估方案，在孟加拉国不同季节观察到的太阳辐射下，评估了SODIS的细菌灭活潜力，并使用PET瓶和塑料袋对透射和反射反应器进行了SODIS实验。在夏季，透射型PET反应器在暴露于阳光下6到8 hr时，观察到对数降低值（LRV）大于5，并且处理后的水符合饮用水中零菌落形成单位/ 100 mL的微生物标准。在季风和冬季，使用反射反应器可使LRV> 4分别暴露于阳光下16小时和8小时。发现塑料袋比PET更有效。根据Weibull模型估计，为SODIS应用可保持安全的暴露时间，以达到4.0 LRV，并防止处理后水中的微生物重新生长。在经过处理的水中观察到微生物大量重新生长，因此建议将SODIS与其他HWT工艺一起用于饮用水供应不安全的社区。