Solar disinfection of water for diarrhoeal prevention in southern India

Abstract

Aims: To evaluate the efficacy and acceptability of solar irradiation in the prevention of diarrhoeal morbidity in children under 5 years of age, in an urban slum in Vellore, Tamil Nadu. Methods: A total of 100 children were assigned to receive drinking water that had been subjected to solar disinfection in polyethylene terephthalate bottles. One hundred age and sex matched controls were also selected. Both groups were followed by weekly home visits for a period of six months for any diarrhoeal morbidity. At the end of the follow up period, the acceptability of the intervention was assessed by interviews, questionnaires, and focus group discussions. Results: There was significant reduction in the incidence, duration, and severity of diarrhoea in children receiving solar disinfected water, despite 86% of the children drinking water other than that treated by the intervention. The incidence of diarrhoea in the intervention group was 1.7 per child-year, and among controls 2.7 per child-year, with an incidence rate ratio of 0.64 (95% CI 20.48 to 0.86). The risk of diarrhoea was reduced by 40% by using solar disinfection. In qualitative evaluation of acceptability, most women felt that solar disinfection was a feasible and sustainable method of disinfecting water. Conclusions: Solar disinfection of water is an inexpensive, effective, and acceptable method of increasing water safety in a resource limited environment, and can significantly decrease diarrhoeal morbidity in children.

Drinking water and sanitation: household survey for knowledge and practice in rural area, Magudanchavadi, Salem district, India

“…11 Alternative pointof-use disinfection methods such as solar water treatment, point-of-use chlorination and storage of water in narrowmouthed vessels need to be explored. 18,19,20,21 Considering the contamination of all water samples at the household level, end-user disinfection is likely to be more effective in such settings. 22 However, such methods may not be sustainable over longer periods or may not be costeffective in rural India.…”

How valuable are environmental health interventions? Evaluation of water and sanitation programmes in India

“…For households that boiled their water, we relied on previously reported estimates of the cost of boiling water 27,35 (i.e. the estimated cost of boiling 5 litres was 27 Indian rupees (Rs), or US$ 0.68) and assumed 5 litres of boiled water per day provided enough drinking water in these households.…”

Optimizing the solar water disinfection (SODIS) method by decreasing turbidity with NaCl

“…The effectiveness of the SODIS method at decreasing diarrheal incidence has also been investigated in epidemiological intervention studies and has proven to be credible: a decrease in diarrhea incidence by as much as 86% has been observed (Centre for Disease Control 2008; Graf et al 2010;Meierhofer 2006;World Health Organization 2002). The method has shown to be particularly effective at reducing diarrhea in children under the age of five (Conroy et al 1995;1999;Graf et al 2010;Rai et al 2010;Rose et al 2006).…”