Browsing by Author "Bott, Charles"
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- Electron beam treatment for the removal of 1,4-dioxane in water and wastewaterPearce, Robert; Li, Xi; Vennekate, John; Ciovati, Gianluigi; Bott, Charles (IWA Publishing, 2023-01)Electron beam (e-beam) treatment uses accelerated electrons to form oxidizing and reducing radicals when applied to water without the useof external chemicals. In this study, electron beam treatment was used to degrade 1,4-dioxane in several water matrices. Removal improvedin the progressively cleaner water matrices and removals as high as 94% to 99% were observed at a dose of 2.3 kGy in secondary effluent.1,4-dioxane removal was confirmed to be primarily through hydroxyl radical oxidation. The calculated electrical energy per order was foundto be 0.53, 0.26, and 0.08 kWh/m(3)/order for secondary effluent (Avg. TOC 9.25 mg/L), granular activated carbon effluent (TOC 3.46 mg/L), andultrapure water, respectively, with a 70% generation and transfer efficiency applied.
- Evaluation of preformed monochloramine for bromate control in ozonation for potable reusePearce, Robert; Hogard, Samantha; Buehlmann, Peter; Salazar-Benites, Germano; Wilson, Christopher; Bott, Charles (Pergamon-Elsevier Science, 2022-03-01)Bromate, a regulated disinfection byproduct, forms during the ozonation of bromide through reactions with both ozone and hydroxyl radical. In this study, preformed monochloramine was evaluated for use as a bromate suppression method in pilot testing of wastewater reuse with an average bromide concentration of 422 +/- 20 mu g/L. A dose of 3 mg/L NH2Cl-Cl-2 decreased bromate formation by an average of 82% and was sufficient to keep bromate below the MCL at ozone doses up to 8.6 mg/L (1.2 O-3:TOC). Removal of 1,4-dioxane through ozonation decreased with increasing NH2Cl dose, confirming that monochloramine suppresses bromate formation, at least in part, by acting as a hydroxyl radical scavenger. This may negatively impact oxidation objectives of ozonation in reuse applications. Increasing monochloramine contact time did not improve bromate suppression, indicating that monochloramine probably did not mask bromide as NHBrCl or other haloamines prior to ozonation. However, NHBrCl and NH2Br may be formed from reactions between HOBr and NH2Cl and excess free ammonia during ozonation. NDMA was formed by ozonation at concentrations up to 79 ng/L and was not enhanced by NH2Cl addition.