Laboratory Efficacy and Disinfection by-Product Formation of a Coagulant/Disinfectant Tablet for Point-of-Use Water Treatment

• Main Authors: Félix Légaré-Julien, Olivier Lemay, Ulysse Vallée-Godbout, Christian Bouchard, Caetano C. Dorea
• Format: Article
• Language: English
• Published: MDPI AG 2018-11-01
• Series: Water
• Subjects: coagulation; decentralized; disinfection by-products; emergency water treatment; flocculation; household; NaDCC; point-of-use
• Online Access: https://www.mdpi.com/2073-4441/10/11/1567

Coagulant/disinfection products (CDPs) are a point-of-use (POU) water treatment technique that can improve microbial quality, reduce turbidity, and produce a free chlorine residual (FCR), serving as a potentially effective option for decentralized water treatment in a variety of contexts, including humanitarian emergencies. A novel CDP with a sodium dichloroisocyanurate-based disinfectant was evaluated with regard to its laboratory water treatment efficacy and generation of disinfection byproducts (DBPs). The CDP water treatment performance was assessed relative to bacteriological (<i>E. coli</i>) humanitarian water quality objectives, World Health Organization recommendations for evaluating POU water treatment options, and available DBP regulations and guidelines. At least 4 log₁₀ <i>E. coli</i> reductions, for a &#8220;highly protective&#8222; status with regard to bacterial reductions, were attained in the tested conditions. Treated waters were consistently below 10 MPN/100 mL with regard to <i>E. coli</i> concentrations, with the majority of samples showing no detectable <i>E. coli</i>. For most conditions, target FCR values were not attained. Treated water turbidity levels were mostly between 5 NTU and 10 NTU. DBP levels were below the regulatory and health-based targets for both families of DBPs studied. This study has served to identify the performance envelopes of the CDP tested under challenging conditions.