Web‐Based Applications to Simulate Drinking Water Inorganic Chloramine Chemistry

Abstract

Two web-based applications (WBAs) relevant to drinking water practice are presented to simulate (1) inorganic chloramine formation and stability, including an example inorganic chloramine demand reaction for organic matter, and (2) breakpoint curves. The model underlying both WBAs is a well-established inorganic chloramine formation-and-decay model. The WBAs were developed to be freely accessible over the Internet as web pages (https://usepaord.shinyapps.io/Unified-Combo/ and https://usepaord.shinyapps.io/Breakpoint-Curve/), providing drinking water practitioners (e.g., operators, regulators, engineers, professors, students) with learning tools to explore inorganic chloramine chemistry in an interactive manner without requiring proprietary software or user modeling expertise. The WBAs allow the user to specify two side-byside simulations, providing a direct comparison of impacts associated with changing simulation conditions (e.g., free chlorine, free ammonia, and total organic carbon concentrations; pH; total alkalinity; and temperature). Once completed, the user may download simulation data to use offline. The WBAs' implementation, validation, and example simulations are described.

UV Photolysis of Mono- and Dichloramine Using UV-LEDs as Radiation Sources: Photodecay Rates and Radical Concentrations

“…The experimentally obtained values were consistent with (<10% difference) those predicted by the web-based model developed by Wahman (Figure S5). 43 Note that the Wahman model also yielded predictions of the dynamic behaviors of NHCl 2 and NCl 3 resulting from NH 2 Cl self-decay (Figure S5a). Similarly, the Wahman model allowed simulation of the pH-dependence of NHCl 2 self-decay, which also indicated corresponding behaviors of NH 2 Cl and NCl 3 that resulted from NHCl 2 selfdecay (Figure S5b).…”

Real-Time Measurements of Gas-Phase Trichloramine (NCl3) in an Indoor Aquatic Center

“…57 Solution pH may also be relevant as it influences the distribution of the inorganic chloramines. 58,59 The gas-phase CO 2 concentration increased with swimmer counts, following a similar trend as that of the gas-phase NCl 3 concentration. Sudden rises and gradual decays in gas-phase CO 2 concentrations were observed at the beginning and end of the preliminary and final races on November 22 and 23, with peak concentrations between 903 and 922 ppm in the bulk air during the sessions.…”

“…In general, Henry’s law constants display temperature dependence that can be described by the Van’t Hoff equation . Solution pH may also be relevant as it influences the distribution of the inorganic chloramines. , …”

Review of chloramine decay models in drinking water system

“…The advantage of this model is that it can be used as a process control simulator by generating various process scenarios such as monochloramine decay under different dosing conditions, different initial chlorine and ammonia concentrations, and different chlorine to ammonia ratios. Wahman 79 developed web based applications (WBAs) to simulate inorganic chloramine chemistry in drinking water system. The application is based on the reaction schemes proposed by Jafvert and Valentine 18 and Vikesland et al 12 and the NOM reactions proposed by Duirk et al 10 Under plug flow condition, the WBAs assumes that chemical additions are immediately and completely mixed with no localized concentration gradients.…”

“…Wahman 79 developed web based applications (WBAs) to simulate inorganic chloramine chemistry in drinking water system. The application is based on the reaction schemes proposed by Jafvert and Valentine 18 and Vikesland et al 12 and the NOM reactions proposed by Duirk et al 10 Under plug flow condition, the WBAs assumes that chemical additions are immediately and completely mixed with no localized concentration gradients.…”