Evaluation of semidecentralized emergency drinking water treatment

Abstract

This study evaluates the potential for a novel semidecentralized approach that uses coagulant disinfectant products (CDPs) for humanitarian water treatment, by testing two commercially available products (CDP-W and CDP-T). Their performances were evaluated against the relevant water quality treatment objectives (The Sphere Project) under laboratory conditions, using a standardized testing protocol with both synthetic and natural surface test waters. Tests indicated a satisfactory performance by one of the products (CDP-W) with respect to humanitarian water quality objectives, (i.e., free chlorine residual, pH, and turbidity) that was dependent on initial water quality characteristics. Adequate bacterial inactivation (final thermotolerant coliform concentration of < 1 cfu/100 mL) was always attained and log reductions of up to 5 were achieved. The other product (CDP-T) did not exhibit any measurable coagulation and disinfection properties, indicating the variability of product quality and the need to conduct evaluations such as the ones presented in this study. Such results are of relevance to relief agencies delivering water supply interventions.

Keywords:

• Coagulation
• disinfection
• drinking water
• emergency
• flocculation
• semidecentralized
• supply
• treatment

Acknowledgment

Control Chemicals Ltd. (South Africa) and Oxfam GB are acknowledged for supplying samples of Watermaker and Tigitech, respectively, used in this study. No financial support was given by either product manufacturer. The funders and product manufacturers had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Funding

Océane Eloidin was supported with funds from the Ecole d'Ingénieur du CESI. Parts of this study were supported by a NSERC Discovery Grant. The authors are grateful to Félix Légaré-Julien and Olivier Lemay for help with the laboratory work – both were partially supported by a grant from Ministère de l'Éducation, du Loisir et du Sport. Caetano C. Dorea acknowledges the Visiting Research Fellowship (UNIR) provided by CNPq (Grant 400576/2013-9).