Evaluation of Ozonation, Enhanced Coagulation, and Biofiltration for the Control of Disinfection By-Products in Drinking Water
Public Deposited- Last Modified
- February 27, 2019
- Creator
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Chaiket, Thom
- Affiliation: Gillings School of Global Public Health, Department of Environmental Sciences and Engineering
- Abstract
- Pilot-plant studies were conducted at the Indianapolis Water Company's White River Filtration Plant to assess the effectiveness of ozonation, enhanced coagulation, and biofiltration in controlling disinfection by-products in the filtered water. Nine experiments were conducted; operating variables included point of ozonation with respect to coagulation, pH of ozonation and coagulation, ozone dose and bromide conditions. Performance was assessed by monitoring pertinent water quality parameters and the reduction of trihalomethane (THM4) and haloacetic acid (HAA9) formation potentials under uniform formation conditions (UFC). The results showed that White River water was not amenable to TOC removal by coagulation. Ozonation, biofiltration, and adjustment of pH did not enhance TOC removal efficiency. None the less, a significant amount of THM4 and HAA9 precursors were removed, with overall removals as high as 66% and 81% respectively. Coagulation and ozonation were equally effective in removing precursors, and biofiltration was found to be more effective with ozonation placed after coagulation and settling. The relative reduction in DBP formation potentials tracked the relative reduction in UV absorbance; This parallel provided insights into the high DBP removal despite low TOC removal. From the regulatory standpoint, all operations were capable of producing filtered water that met Stage I requirements under UFC conditions. As for the effects of bromide on DBP speciation, bromo-substituted THMs and HAAs accounted for up to 90% and 50% in the irrespective classes when the water was spiked with 200 μg/L of bromide. Additional data analysis found significant correlation between the molar ratios CHBrCl2/CHCl3 and BrCl2AA/Cl3AA, and CHBrCl2/CHCl3 and BrClAA/Cl2AA.
- Date of publication
- August 1999
- DOI
- Resource type
- Rights statement
- In Copyright
- Advisor
- Weinberg, Howard
- DiGiano, Francis A.
- Singer, Philip
- Degree
- Master of Science in Environmental Engineering
- Academic concentration
- Environmental Engineering
- Degree granting institution
- University of North Carolina at Chapel Hill
- Graduation year
- 1999
- Language
- Deposit record
- 56f7e058-1c97-4774-9946-7afdcd8e0e36
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