Community challenges when using large plastic bottles for Solar Energy Disinfection of Water (SODIS)

Abstract

BackgroundCommunities living in developing countries as well as populations affected by natural or man-made disasters can be left at great risk from water related diseases, especially those spread through the faecal-oral route. Conventional water treatments such as boiling and chlorination can be effective but may prove costly for impoverished communities. Solar water disinfection (SODIS) has been shown to be a cheap and effective way for communities to treat their water. The exposure to sunlight is typically carried out in small volume plastic beverage bottles (up to 2 l). Given the water requirements of consumption and basic personal hygiene, this may not always meet the needs of communities. Recent work has shown 19-L plastic water dispenser containers to be effective SODIS reactors, comparable in efficacy to PET bottles. In this paper we outline the need for studying SODIS in large volumes and discuss 4 main associated challenges.DiscussionApart from clean water needed for consumption, access to adequate water is essential for sanitation and hygiene. Contamination of treated water through unwashed hands or vessels contributes heavily to the spread of water borne pathogens in communities. Traditional water treatments such as boiling and chlorination can be effective but may prove financially burdensome for low income communities. SODIS in large vessels could be used as a simple method to meet water requirements in low income and disaster affected populations. However, there have been some concerns associated with the conventional SODIS method; we identify the main ones to be: (1) cold or cloudy weather; (2) the fear of leaching in plastic bottles; (3) water turbidity, and; (4) community acceptance.SummaryThe application of SODIS in large bottles like WDCs has the potential to be an efficient and cost effective method of disinfecting water, either for consumption until more rigorous water treatments can be put in place, or for sanitation and hygiene to curb the spread of fecal contamination. Further research is needed that can address some of the limitations and challenges associated with the use of large bottles for SODIS.

A Transdisciplinary Methodology for Introducing Solar Water Disinfection to Rural Communities in Malawi—Formative Research Findings

“…By using a transdisciplinary team to achieve codesign and development of the SODIS, the present study has aimed to overcome many of the barriers identified to household water treatment and specifically SODIS uptake through both the final prototype design and the development of supporting materials that are context appropriate and address specific behavioral determinants (Rainey and Harding 2005; Tamas et al 2009; Kraemer and Mosler 2012; McGuigan et al 2012; Mosler et al 2013; Ojomo et al 2015; Borde et al 2016; Keogh et al 2017). Through the use of the theory of change developed by De Buck et al (2018), we collated data and held community discussions that examined the context fully and informed both the actual HWTS design and appropriate promotional techniques to use (Mosler 2012).…”

“…However, despite this, adoption could be described as moderate, with uptake ranging from between 9% to 90% (Rainey and Harding 2005; Tamas et al 2009; du Preez et al 2011). Key reasons for lack of uptake of SODIS have been reported as 1) relatively small volume (2 L) of water per bottle means that numerous bottles need to be used to meet household demand; 2) in cases of high turbidity, filtration may be needed to reduce the turbidity of water preferably to below 30 NTU for effective disinfection, therefore increasing the labor involved; 3) uncertainty about its safety, when people do not believe that water is safe and some have concerns about the possibility of harmful chemicals from PET bottles leaching into the water after long‐term exposure in the sun; 4) the long treatment time to achieve disinfection (≥6 h) when compared to other methods such as chlorination; and 5) lack of integration of behavior change programs that address not only the technical aspects but also contextual and psychosocial factors which may affect uptake and sustained use (Rainey and Harding 2005; Tamas et al 2009; Kraemer and Mosler 2012; McGuigan et al 2012; Mosler et al 2013; Borde et al 2016; Keogh et al 2017).…”

Barriers and Enabling Factors Associated with the Implementation of Household Solar Water Disinfection: A Qualitative Study in Northwest Ethiopia

“…A study by Rainey and Harding in Nepal 26 pointed out that water treatment was a minor aspect of women's concerns and that women's domestic and farming workload was the most common barrier. 36 In this study, the participants revealed that because of personal weakness of family members, some parents paid less attention to HWT. These findings are also supported by William et al's 37 qualitative study findings in Haiti, which indicated that because of negligence, laziness, or belief that water treatment was not essential, individuals did not treat their water at home.…”

“…High turbidity was observed to reduce the effectiveness of SODIS by reducing the effect of sunlight penetration across water depth, thus preventing microbes from inactivation. 14,36 In this study, the participants suggested early morning collection of water from the sources (i.e., "before birds singing" in local speech) because contact of animals with water that disturbs and contaminates the water is less likely and letting the collected water for simple sedimentation at home before filling SODIS bottles to minimize the effect of turbidity.…”

Coupling Extracts of Plant Coagulants With Solar Disinfection Showed a Complete Inactivation of Faecal Coliforms

“…There are also concerns about the use of PET plastic bottles for SODIS water treatment . The toxicological concern of SODIS is about the chemicals that may leach from the plastic into the water as the container material degrades in sunlight . However, Wegelin et al filled PET bottles, exposed them to sunlight for up to 6 h and no photoproducts from plastic could be measured in the treated water at the temperature and UV exposure encountered in field and laboratory tests.…”