Odour reduction interventions for simple pit latrines in rural Ethiopia: a randomized study

Pit latrines are promoted in resource-limited settings, but unpleasant odours may deter their use. In this study, latrines in rural Ethiopia were randomized to the addition of cooking ash, the addition of boiling water or neither. Study staff ranked odour on a 6-point scale before and approximately 24 h after intervention. Following intervention, odour grades were on average 0.2 points lower (95% confidence interval [CI] 0.7 lower to 0.3 higher) in ash-treated latrines and 0.4 points lower (95% CI 0.9 lower to 0.1 higher) in boiled water-treated latrines, although the difference between the three groups was not statistically significant (p = 0.21). Larger studies might detect a smaller difference.