The Effects of Coagulation, Ozonation, and Biodegradation on the Activated Carbon Adsorption of Aquatic Humic Substances
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Harrington, Gregory W. The Effects of Coagulation, Ozonation, and Biodegradation On the Activated Carbon Adsorption of Aquatic Humic Substances. 1987. https://doi.org/10.17615/p2kx-0596APA
Harrington, G. (1987). The Effects of Coagulation, Ozonation, and Biodegradation on the Activated Carbon Adsorption of Aquatic Humic Substances. https://doi.org/10.17615/p2kx-0596Chicago
Harrington, Gregory W. 1987. The Effects of Coagulation, Ozonation, and Biodegradation On the Activated Carbon Adsorption of Aquatic Humic Substances. https://doi.org/10.17615/p2kx-0596- Last Modified
- February 28, 2019
- Creator
-
Harrington, Gregory W.
- Affiliation: Gillings School of Global Public Health, Department of Environmental Sciences and Engineering
- Abstract
- The United States Environmental Protection Agency is currently in the process of adding or lowering the maximum contaminant levels of many organic compounds, including trihalomethanes (THMs). As a result, many water treatment facilities are expected to consider the use of processes such as ozone oxidation and granular activated carbon (GAC) adsorption. Since these processes are quite expensive, accurate design of these systems for the removal of humic substances, the precursors of THMs, is essential. This work examined the effects of bench scale coagulation, ozonation, and biodegradation processes on the adsorption of aquatic humic substances obtained from a swamp lake in southeastern Virginia. The equilibrium adsorption behavior was described by dividing each humic mixture into several fictive components and ideal adsorbed solution theory (IAST) was then used to find the Freundlich parameters and initial concentration of each component. IAST was found to provide adequate descriptions of humic substance adsorption, even though many assumptions in the model were not considered to be valid for humic solutions. This multicomponent adsorption model was used to show that compositional changes were responsible for increased adsorbability upon coagulation and for decreased adsorbability upon ozonation and biostabilization. Unfortunately, systematic changes in the IAST parameters were not found to occur with increasing ozone dose, thereby implying that accurate prediction and design of combined ozone and GAC systems may be difficult. However, a normalized adsorption isotherm showed some promise in this regard although the technique may not be applicable to kinetic systems. External mass transfer characteristics of humic solutions were examined with a mini-column adsorber. The free liquid diffusion coefficient was found to increase upon coagulation while no significant changes were observed after ozonation and biostabilization. Internal mass transfer characteristics were examined with a pore and surface diffusion model. The overall mass transfer rate was found to increase after coagulation and after ozonation and biostabilization. However, tests with three different ozone doses showed no change in mass transfer rates with ozone dose. In addition, the techniques used in this work were not found to be capable of describing the mechanism of humic substance diffusion.
- Date of publication
- December 1987
- DOI
- Resource type
- Rights statement
- In Copyright
- Advisor
- DiGiano, Francis A.
- Singer, Philip
- Miller, Cass T.
- Degree
- Master of Science in Environmental Engineering
- Academic concentration
- Water Resources Engineering
- Degree granting institution
- University of North Carolina at Chapel Hill
- Graduation year
- 1987
- Language
- Deposit record
- 4229e0fb-b010-4ede-aa50-9d4a2f0726fb
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