A novel water treatment device that delivers chlorine automatically via public taps without the need for electricity, was able to reduce child diarrhea by 23% compared with controls.
The randomized trial following more than 1,000 children took place over 14 months in two urban neighbourhoods of Bangladesh and was recently published in The Lancet Global Health journal.
Clean water is still a major problem in poor urban communities in low-income countries, where contamination by bacteria can lead to high rates of diarrheal diseases such as cholera and typhoid. Worldwide, an estimated 1 billion people who have access to piped water are drinking water that does not meet international safety standards.
In this study, the device used a low chlorine dose, which increased taste acceptability and achieved high uptake while still improving drinking water quality.
“Chlorination is one of the cheapest and most widely available methods to make drinking water safe, but poor taste and bad smell of chlorinated water are major barriers to adoption,” said co-author Dr Sonia Sultana from the International Centre for Diarrhoeal Diseases Research, Bangladesh. “Our findings indicate that automated chlorine dosing below the taste detection threshold has the potential to be transformative by ensuring high adoption rates and will hopefully help progress towards the global target of universal access to safe and affordable drinking water.”
The authors say that chlorinating water at the point-of-collection could be an effective, scalable strategy in low-income urban settings to reduce diarrheal diseases.
In this study, researchers used a novel treatment device that automatically dispenses small amounts of chlorine to water from public taps and shared hand pumps. In the device, water flows past solid tablets of chlorine that dissolve into the water to treat it (see infographic above).
Identical dispensers were installed at 100 shared water points in two low-income neighbourhoods in Bangladesh (Dhaka and Tongi) fed by piped water that is delivered intermittently, as is common in low-income settings. Water points were randomly assigned to have their drinking water automatically chlorinated (intervention) or to be treated with vitamin C (control group).
Chlorine residual was detected at the point of collection from shared taps 83% of the time in the treatment group compared to 0% of the time in the control group. E. coli contamination was detected in 15% of tap samples in the treatment group compared with 64% in the control group.
Results showed that, over 14 months, children in the treatment group had substantially less diarrhea than those in the control group (156 cases out of 2,073 child observations [7.5%] vs 216/2,145 [10%]).
The intervention had the largest health benefits among children in Dhaka, reducing diarrhea by 34% compared to 7% in Tongi. The authors speculate that this variation in effect probably resulted from the poorer water quality in Dhaka at the start of the study (e.g., 87% of tap samples in Dhaka were contaminated with E. Coli compared with 50% in Tongi) and because Dhaka receives water that spends much longer travelling through unpressurized pipes, enabling contamination and sewage to seep into the system.
Despite these achievements, the study has some limitations. Diarrhea episodes were based on caregiver-reported data, which might not accurately represent children’s illness, and participants may have drunk water from other sources, although less than 4% of respondents reported doing so.This device is also not a “one-size-fits-all” solution as it does rely on people having access to piped water.
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