Regulated disinfection byproduct formation over long residence times

Divergent Fate and Roles of Dissolved Organic Matter from Spatially Varied Grassland Soils in China During Long-Term Biogeochemical Processes

“…The alteration of DBP-FP and toxicity was strongly correlated with the variations in DOM quantity ( P < 0.001) (Figure S21). The chlorine reactivity of DOM were positively correlated to the SUVA 254 and HMW fraction ( P < 0.001) (Figure e), since the compounds with higher aromaticity and larger molecular size are more reactive to form THMs and HAAs. , The STHM-FP and SHAA-FP were also positively correlated with the relative abundance of VHMW (PVHMW) and RIII (PIII) compounds ( P < 0.05), respectively (Figure e), as the >30 kDa compounds and the fulvic acid compounds can be THM and HAA precursors. , These results emphasized that the biogeochemical processes of DOM would result in variations in the FP and toxicity of DBPs and the chlorine reactivity of DOM. Importantly, the impacts of grassland soil DOM on drinking water quality and safety would change over long periods of biogeochemical processes in water environments, and the effects are different for the high-HS and low-HS regions (Figure f).…”

Trihalomethane, haloacetic acid, and haloacetonitrile behaviors in water heater storage tanks

“…The lower normalized HAA formation during the control studies relative to that of TTHM was expected because the formation kinetics was faster for HAAs than for THMs, thus more of the relative HAA formation occurred over the 24 h in the distribution system. 43,44 Based on the average initial chlorine residual of 0.7 mg L −1 and a reactivity of 15 μg HAA5 mg −1 chlorine from Kennedy et al, 56 the estimated additional HAA5 formation during the control studies would be 11 μg L −1 until the chlorine residual was consumed. This is consistent with our findings where the measured results at all three temperatures yielded an average additional HAA5 formation of 12 μg L −1 .…”

“…This has been demonstrated in several other studies at pH 8. For example, Kennedy et al 56 reported an increase in the concentration of TTHM and HAA5 by factors of 2.0 and 1.5, respectively after 56 days when the temperature was increased from 10 to 22 °C. Dickenson 58 found an increase in the concentration of TTHM and HAA5 by factors of 1.7 and 1.3 respectively after 5 days when the temperature was increased from 20 to 30 °C.…”

Environmental isotopes (δ18O–δ2H, 222Rn) and electrical conductivity in backtracking sources of urban pipe water, monitoring the stability of water quality and estimating pipe water residence time

“…The residence time of pipe water, the infiltration of exogenous substances, in the case of negative pressure in the pipes, as well as the mixing of water from different sources could lead to changes in the water quality. A longer residence time often leads to a greater probability of water contamination within the pipe network (Tinker et al, 2009;Sekozawa et al, 2013;Zlatanović et al, 2017;Geng et al, 2021;Kennedy et al, 2021). Thus, water residence time in pipe network is a variable of interest for urban water utilities; it can be determined by using methods such as hydraulic models (Tinker et al, 2009), chlorine decay model (Bhadula et al, 2021;Geng et al, 2021), or, to a lesser extent, by measuring trihalomethane, a by-product of the chlorine-organic matter interaction (Sekozawa et al, 2013).…”