A School-based Trial Protocol in Community Promotion of Solar Water Disinfection (SODIS): A Case Study of Ndagwe Sub County, Central Uganda

Improvement in microbial quality of drinking water by solar disinfection (SODIS) results in reduced diarrheal episodes among users. In this study, a randomized cluster stepped wedge study design was used to assess the use of primary school pupils as community promoters of SODIS technology in Ndagwe sub county, central Uganda. The intervention (SODIS) was introduced to pupils in the different school clusters at different time points throughout the year. Pupils were to only drink SODIS treated water both at school and home during intervention period. The effect of SODIS on prevalence of diarrhea and gastro-intestinal complaints severe enough to cause pupil absenteeism was monitored. In addition to SODIS treatment, the study also assessed a field comparison SODIS efficacy in both glass and PET reactors.

Results revealed that school children were effective promoters of SODIS with community use of the technology improving from 4.9% at baseline to over 60% post-intervention. SODIS also significantly improved microbial quality of water with 61% and 72.7% of all treated samples meeting the 0 CFU/100 mL WHO conformity standard for drinking water for both E. coli and E. faecalis respectively. In comparison, only 13% and 16 % of untreated samples met this standard for both bacteria respectively.

Generally, overall pupil absenteeism due to diarrhea and gastro-intestinal complaints was not significantly associated with SODIS treatment (IRR 0.63 Cl 0.29 to 1.39 p= 0.222). However, absenteeism due to diarrhea and gastro-intestinal complaints was significantly associated with phase of SODIS intervention. In the last phase when all pupils were using the intervention absenteeism significantly (IRR 0.51, Cl 0.31 to 0.83 p=0.012) dropped from a baseline average of 1.9± 2.2 days to 0.2±0.6 days. Finally, no significant difference was found in SODIS efficacy between glass and PET reactors under real field conditions.