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Chlorinous flavors are a leading cause of customers' dissatisfaction with drinking water. Potential differences in chlorine perception were investigated by conducting sensory testing experiments in France and Spain to assess consumers' sensory sensitivity (chlorine flavor detection threshold and supra-threshold intensity) as well as their liking of and acceptability for chlorinated solutions. In both countries, two groups of panelists were constituted based on their water drinking habits (tap vs. bottled water). Chlorine flavor detection threshold was found to vary depending on countries (0.17 mg/L Cl-2 in France and 0.56 mg/L Cl-2 in Spain). Taking into account that mean flavor detection thresholds were found in agreement with chlorine residuals delivered at tap, it is likely that habituation may explain sensitivity differences between countries. This hypothesis is supported by results showing no significant sensitivity difference at detection threshold levels, but significant differences between tap water and bottled water consumers at supra-threshold levels (flavor intensity). In addition, consumers' liking and acceptability for chlorinated water was found to be in agreement with sensitivity: the higher the sensitivity the lower the acceptability for chlorinated waters. Thus, French consumers or bottled water drinkers showed a lower appreciation of chlorinated water solutions and were especially less inclined to accept chlorinated water as drinking water delivered at tap

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The internal corrosion of cast iron and steel pipes is one of the main issues that drinking water distribution operators are facing. This study evaluated the relevance of 10 known corrosion indices according to their estimate of corrosion rate and iron particle release for 20 different water qualities. Pilot-scale contact trials were run over 45 days using cast iron and steel coupons. Corrosion rate was measured by coupon weight-loss and by an online linear polarization rate probe. Particle release was monitored by an online turbidimeter. The results showed that none of the indices properly predicted the level of risk associated with each water and that corrosion and particle release were not correlated. Two novel indices were developed to predict the corrosion and particle release risks independently of each other. The corrosion index showed a strong linear correlation with the corrosion rate of cast iron and slightly less reliable results for steel. The Particle Emission Index presented good correlation with turbidity in waters following contact with cast iron. These two indices thus showed interesting potential as tools to limit internal corrosion risks for metal pipes in water distribution networks.

To mitigate pipe and water quality degradation in distribution, treatment targets were established to continuously control the corrosion potential of drinking water towards cement, lead and iron materials at a 225 MLD surface water treatment plant. Indicators were identified to estimate the corrosion potential of water for each of the 3 materials: the Langelier Saturation Index (LSI) for cement, pH for lead and a novel corrosion index for iron. Linear Polarization Resistance (LPR) probes equipped with cast iron and lead electrodes provided direct and continuous measurements of actual lead and iron corrosion rates for finished water. Corrosion control was achieved by adjustments to caustic soda doses. The set-point for finished water pH was determined with a site-specific algorithm using online values for temperature, pH, and conductivity as surrogate for calcium and alkalinity. Over the 7 months of implementation, measured iron corrosion rates were maintained well below the established threshold of 50 μm/year. Lead corrosion rates varied from 20 to 40 μm/year with higher levels occurring when pH dropped below 7.5. The full-scale experience validated a treatment strategy and demonstrated the feasibility of using LPR probes for online monitoring of corrosion potential on drinking water matrices.