Variations of disinfection by-product levels in small drinking water utilities according to climate change scenarios: a first assessment

Abstract

In Québec, Canada, shifts in climate patterns (i.e., rainfall increase) could have consequences on source water quality due to the intensification of surface/groundwater runoff contamination events, leading to a decline in drinking water treatment efficiency and ultimately disinfection by-products (DBPs) formation following treatment. To assess the impacts of climate change (CC) scenarios on DBP formation, a suite of models linking climate to DBPs was used. This study applies three emissions scenarios (B1, A1B and A2) for three 30-year horizons (2020, 2050 and 2080) in order to produce inputs to test several DBP models (total trihalomethanes (TTHMs), haloacetic acids and haloacetonitriles). An annual increase is estimated for all DBPs for each CC scenario and horizon. The highest seasonal increases were estimated for winter for all DBP groups or species. In the worst-case scenario (A2-2080), TTHMs could be affected more particularly during winter (þ34.0%), followed by spring (þ16.1%) and fall (þ4.4%), whereas summer concentrations would remain stable (À0.3 to þ0.4%). Potentially, small water utilities applying only a disinfection step could be more affected by rising TTHMs concentrations associated with CC than those having implemented a complete water treatment process (coagulation-flocculation, filtration and disinfection) with þ13.6% and þ8.2% increases respectively (A2-2080).

Climate Changes and Drinking Water in Sustainable Cities: Impacts and Adaptation

“…The objective is to explore and estimate the impact of future possible variations in temperature and precipitation -associated with climate change scenarios -on the probability of THM4 (total trihalomethanes) concentrations exceeding a specific threshold (80 μg/L (based on the mean annual regulatory threshold from the Quebec, Canada, drinking water regulation) [15].…”

Predicted Impact of Climate Change on Trihalomethanes Formation in Drinking Water Treatment

“…Climatic conditions are changing 1 , and this appears to be altering surface water quality with potential public health implications, especially water treatability in drinking water treatment plants (DWTPs) 2,3 . This becomes particularly evident in regions with extensive peatlands in drinking water catchments where warming effects have been related to increasing dissolved organic carbon (DOC) concentrations, which then impacts water treatability in DWTPs 4–8 . DOC is a precursor for the formation of disinfection by-products (DBPs), some of which are regulated due to public health concerns.…”