DrinkingDisinfection by-products (DBPs) pop up when chemical disinfectants, like chlorine, mix with natural stuff, bromide, or iodide in source water. Small drinking water systems often face a bigger DBP risk because they don’t have the fancy monitoring and treatment big utilities do. We’ve found over 700 DBPs so far, but the EPA’s Stage 2 rule only covers a few. Luckily, we can use predictive models, looking at things like precursor levels, disinfectant dose, pH, temperature, and contact time. These models help operators guess how many non-regulated DBPs are forming so they can act fast.

Author Full Names: Guilherme, Stephanie; Rodriguez, Manuel J.
Source:ENVIRONMENTAL MONITORING AND ASSESSMENT, 189 (11):10.1007/s10661-017-6296-5NOV 2017
Language:English

Abstract: Only trihalomethanes (THMs) and haloacetic acids (HAAs) are regulated in drinking water. Most DBPs, though, aren’t. We don’t know much about these non-regulated DBPs, especially in small water systems (SWS). It’s a tricky situation because SWS are actually more likely to have DBP issues since they can’t always afford the right treatment to get rid of DBP precursors. Plus, DBP tests are expensive, so SWS struggle to really know what’s in their water. This study aimed to estimate non-regulated DBP levels in SWS using simple, everyday measurements. Since there wasn’t much info on non-regulated DBPs in SWS, we ran a sampling program in 25 SWS across two Canadian provinces. We checked out five DBP families: THMs, HAAs, haloacetonitriles (HANs), halonitromethanes (HNMs), and haloketones (HKs). We then built multivariate linear mixed regression models. These models estimate HAN, HK, and HNM levels based on water quality at the treatment plant, regulated DBP concentrations, and leftover disinfectant levels. The models worked well, with R-2 values from 0.77 to 0.91, depending on the compounds and conditions (like season and treatment type). We checked these models with a separate database, and it showed they could likely work for similar SWS in North America.

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Source: Water Feed