10/19/2021 (2) - Laserfiche WebLink

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Kim ey>Morn Page 14 Recently, the EPA issued the proposed revisions to the LCR (Lead and Copper Rule Revision) that proposed removal of calcium as a water quality parameter for corrosion control. This development deviates from corrosion indices, such as LSI and CCPP as being indicators of corrosion control, due to their reliance on calcium hardness to yield scale -forming water. In its place, parameters like alkalinity, dissolved inorganic carbonate (DIC), and orthophosphate residual are considered for enhancing corrosion control. Orthophosphate inhibitors are used to generate a protective film on the inside of distribution and customer plumbing, while also providing alkalinity to resist pH changes. From January through March 2021, IRCU has received customer complaints regarding water quality aesthetics. These complaints are variable in description of color, smell, and taste. The complaints were reviewed throughout the system and incorporated in the water system model to understand if there was a direct relationship with water age. This exercise was inconclusive, as the complaints were random in location and inconsistent with regards to description and water age. However, one common theme from some of the customer complaints is the presence of turbidity (cloudiness, haziness) in the finished water and the ability to reduce this turbidity through flushing of the distribution mains nearby and the customer's plumbing. In one instance, IRCU sampled the water that was flushed from the hydrant and discovered elevated concentrations of calcium, magnesium, iron, and aluminum. Each of these constituents listed is present in the lime slurry statement of content and may have attributed to the water quality discovered. It appears that some areas within the system, in addition to dead end runs, turbidity appears to concentrate until it reaches the customer's residence, where the complaint will ensue, and subsequent flushing will restore water quality in the area. This appears to be a consistent theme for complaints through the system. In effort to address these complaints, IRCU is in the process of evaluating system flushing program. Since 2014, IRCU has conducted water quality sampling (approximately once every 3 months) from the six (6) DBP sampling locations in the distribution system. These sampling locations vary in terms of water age, and locations range from Gifford to the Roseland areas. The water quality parameters tested for consist of calcium, alkalinity, pH, temperature, chlorine residual, and pH. Noteworthy trends include the following: 1. IRCU's ability to increase alkalinity concentrations at each of the six locations. This has translated to less variable pH values measured during the respective sampling events. 2. Decreasing pH throughout the system. The data indicates finished water is trending from the goal of —8.3 towards 8.0. This pH reduction may have attributed to the increase in Lead and copper 90th percentile values discussed herein. The following graphs are provided for each of the six (6) sample locations to demonstrate the trends described herein: 74