Simultaneous prediction of trihalomethanes, haloacetic acids, haloacetonitriles and haloacetamides using simulated distribution system tests

Abstract

This study analysed the spatial and temporal occurrence of 29 disinfection by-products (DBPs) formed by chlorination and chloramination. Four full-scale treatment works and distribution system locations were sampled and results...

Spatiotemporal Variability in N-Nitrosodimethylamine Precursor Levels in a Watershed Impacted by Agricultural Activities and Municipal Wastewater Discharges and Effects of Lime Softening

“…Many drinking water treatment plants in the United States use free chlorine as the primary disinfectant followed by the addition of NH 3 to convert the residual free chlorine to chloramines. 66,67 Short contact with free chlorine potentially destroys some NDMA precursors, resulting in less NDMA formation after converting the residual chlorine to chloramines. 68,69 Thus, the UFC and FP tests represent moderate to worst-case scenarios, respectively, for NDMA formation, while free chlorine exposure followed by NH 3 addition would result in lower and likely more realistic NDMA concentrations.…”

“…One limitation of this study is that NDMA formation was measured by adding preformed chloramines via the UFC and FP tests. Many drinking water treatment plants in the United States use free chlorine as the primary disinfectant followed by the addition of NH 3 to convert the residual free chlorine to chloramines. , Short contact with free chlorine potentially destroys some NDMA precursors, resulting in less NDMA formation after converting the residual chlorine to chloramines. , Thus, the UFC and FP tests represent moderate to worst-case scenarios, respectively, for NDMA formation, while free chlorine exposure followed by NH 3 addition would result in lower and likely more realistic NDMA concentrations . The obvious trade-off with the free chlorine exposure strategy for preoxidizing NDMA precursors is the formation of halogenated DBPs including regulated compounds.…”

Toxicity warning and online monitoring of disinfection by-products in water by electroautotrophic biocathode sensors

“…Trichloromethane is one of the major components of CDBPs ( Sfynia et al, 2022 ), which is classified as a suspected carcinogen by the American Cancer Society as early as 1976 ( Keysser C. 1976 ), and its carcinogenic effects have been confirmed in animals. Dichloromethane is also a typical CDBPs ( Takahashi and Morita, 2010 ), which belongs to the class 2A carcinogens in the list of carcinogens published by the International Agency for Research on Cancer (IARC).…”

Simultaneous Use of Polyphosphate for Sequestration and Antiscaling

“…Previous studies have demonstrated the effectiveness of simulated distribution tests in evaluating scale formation in a water heater, 34 chlorine decay in distribution systems, 35 and TTHM formation. 36 All of these simulations have limitations, but their results are nonetheless considered useful for system optimization.…”

“…Simulated distribution tests are proposed herein as a useful tool for estimating the impact of phosphates on discoloration as a function of water age in pipe systems without running the risk of full-scale experimentation. Previous studies have demonstrated the effectiveness of simulated distribution tests in evaluating scale formation in a water heater, chlorine decay in distribution systems, and TTHM formation . All of these simulations have limitations, but their results are nonetheless considered useful for system optimization.…”