Diseases related to contamination of drinking-water constitute a major burden on human health. Waterborne diseases are of particular concern in populations affected by conflict, natural disasters, famine and mass migrations. In the context of emergencies and disasters that result in large-scale population displacements and densely populated camps, waterborne diseases are a major cause of morbidity and mortality, particularly because the provision of adequate water and sanitation can be fraught with challenges.
The WHO and UNDP estimate that over 1.1 billion people mainly in low income countries lack access to improved water sources and many more lack drinking water. There are approximately 2-3 million drinking water related deaths annually and the figures usually escalate with emergencies following disasters.
A dire need for emergency/ point-of-use (POU) water treatment indeed exists.
Five intervention methods viz; WaterGuard®(Bleach), PUR®(flocculant-disinfectant), Aquatabs® (NaDCC), Micropur®(Ag+) and LifeStraw® membrane filtration were identified as the ones being commonly used. And a highly prospective potential has been identified in MicroSil®(Ag0).
With a clear explanation of the objectives of the work, formal requests for product samples were sent to all the respective product manufacturers. Only two responded and one even provided available published research work on their product. Nonetheless all the tested products were bought off the market from consumer points.
All the treatments were done in accordance with the directions for use as could be available to the consumers. Eschericia coli concentration, free residual chlorine concentration and turbidity of the water were used as criteria for assessing the effectiveness of the respective methods. WaterGuard® and PUR® met the WHO/USEPA 5 log unit bacteriological removal requirement on following the manufacturer?s prescribed directions of use. Aquatabs® failed to satisfy this requirement at the manufacturer?s recommended 30 minutes contact time. But achieved total disinfection (>5 log removal) in 2 hours without doubling the dosage. Micropur®(Ag+) needed a contact time of nearly 24 hours to meet this requirement. At a dosage of 5ppm, MicroSil®(Ag0) gave superior results than Micropur® and obtained total disinfection in 4.5 hours. In their current form, LifeStraw® membranes gave insignificant bacterial removal in the context of this work. But membrane impregnation with MicroSil® greatly improved their performance to nearly 2 log unit removal. Post treatment recontamination was also realised on filtration/storage with a dirty/contaminated filter or container with PUR®, nonetheless, total disinfection was again obtained within an additional 20 minutes following filtration/storage.
Though this work was not designed to compare smell, a difference could still be recognised between the WaterGuard® and the PUR® treated waters. While Aquatabs® did not have any smell effect. Yet no statistical significance was found in the FAC levels that these methods gave.
PUR® gave the best results with turbidity reduction. WaterGuard®, Micropur®, and Aquatabs® have no influence on the turbidity of the water while MicroSil® significantly increased the turbidity. LifeStraw® membranes had the least positive effect on the turbidity.
None of the methods had significant effect on the pH of the water. But notable reductions were observed for WaterGuard® and PUR® in that order. Likewise, PUR® gave the biggest increase in EC followed by Micropur®. WaterGuard® led to a reduction in EC while all the other methods had no significant effect.

In general these emergency interventions were realised to be indeed very expensive in comparison with the conventional treatment methods. Silver based treatments (Micropur® and MicroSil®) were found more expensive amongst them and bleach the most economical.


Auteur: Ronald S. Muenze
Herkomst: CMS, UGent
Referentie: Referentie