AWWA ACE65336

Research has shown a greater potential for polymer materials to impact taste and odor thantraditional metal pipes. These materials leach odorous compounds that when detected byconsumers negatively influence their perception of water quality at the tap (McGuire, 1995;Dietrich, 2006). Polymer pipe materials, which consist of the polymer and additives, leachvolatile (VOCs) and semi-volatile organic (SVOCs) compounds to water which impact eitherwater quality, sensory quality, or both (Anselme et al., 1985; Rigal and Danjou, 1999; Khiari et al.1999; Skjevrak et al., 2003; Marchesan and Morran, 2004). Plumbing materials can alsoconsume residual disinfectant in drinking water, which can lead to changes in tastes and odor andincreased growth or microorganisms. Repeated studies demonstrated that leaching of polymeradditives, organic compounds, and oxidation of the surface of the pipe during extrusion leads toperceptible odors in drinking water. Water utilities strive to avoid sensory problems in thedrinking water because aesthetics play a critical role in consumers perception of both the qualityand safety of drinking water. Thus, if premise plumbing can impact taste and odor at the tap,utilities and consumers want to know this so that they can plan accordingly in the materialschosen for plumbing.This interdisciplinary research performed comprehensive testing of piping materials underrealistic drinking water quality conditions. A unique aspect was that both chemical and consumer-assessedsensory characteristics of water in contact with new materials were determined. Copperand five polymer (cPVC, HDPE, PEX-a, PEX-b, epoxy lining) pipe materials from commercialsources were investigated for their propensity to leach organic chemicals, consume disinfectants,and alter water quality. Replicate seven (7) foot lengths of 3/4 inch (internal diameter) pipes weretested. All pipe materials were certified according to National Sanitation Foundation (NSF-61)standards. The Utility Quick Test (Schweitzer et al., 2002), a standard leaching protocol for newmaterials, was conducted at room temperature using a low alkalinity water of pH 7.8-8 with nodisinfectant, 2 mg/L chlorine, or 4 mg/L monochloramine. Three consecutive cycles of fill andflush were used, with a 72-96 hour period between flushes. A trained human panel used FlavorProfile Analysis (Standard Method 2170) to assess odors. SPME-GC-MS was used to detect andidentify organic compounds. Chlorine and monochloramine were determined using the DPDmethod; TOC was measured with a Seivers low TOC instrument. Includes 12 references.



Keywords: Odor; Pipes; Polymers; Taste; Organics; Water Quality; Standards; Leaching; Linings; Oxidation