AWWA JAW57695

Taste and odor problems in drinking water are the main cause of consumer complaints. However, one common practice, chlorine disinfection, can actually create additional taste and odor issues. Not only does the chlorine have a strong, distinctive smell, but it masks other odor-producing chemicals. As the water makes its way from the treatment plant to the consumer, the chlorine level drops, and the previously masked odors become noticeable. Two chemicals that chlorine masks are geosmin and 2-methylisoborneol (2-MIB), which cause earthy-musty tastes in finished water, even at extremely low concentrations (nanogram-per-litre levels). Little technical data have been published on the sensory interactions between chlorine and odor compounds. This study provides technically sound proof that chlorine has a masking effect on geosmin and 2-MIB and provides a means of reducing this interference to better quantify these components. This article provides a practical and relatively easy way to reduce chlorine in odor samples, allowing odor testers to more easily characterize a water sample's odor profile. Water utilities can use this information in their daily odor evaluations to identify problems and remedy them before a full-scale odor event occurs. Includes 23 references, tables, figures.