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AZO DYE BIODEGRADATION AND INHIBITION EFFECTS ON AEROBIC NITRIFICATION AND ANOXIC DENITRIFICATION PROCESSES

LI, JIN
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1006802895

Abstract Details

2001, PhD, University of Cincinnati, Engineering : Environmental Engineering.
The main objective of this research was to study the fate of acid orange 7(AO7), a common azo dye, under aerobic nitrifying and anoxic denitrifying conditions and its inhibitory effect on these wastewater treatment processes. With the growing understanding of the influence of nutrients on the balance of the ecosystem, nutrient removal from wastewater has become increasingly important. Biological nitrification and denitrification processes are the "key processes" when dimensioning wastewater treatment plants for nutrient removal. Both macroscale and microscale approaches were employed in this research. At microscale, microelectrode techniques were developed and used to study concentration profiles of interest in microbial biofilms in situ. The fabrication and evaluation of a suite of microelectrodes, including ammonium, nitrate, pH, dissolved oxygen and redox potential, were described. Microelectrodes were applied to study the development of an aerobic/anoxic biofilm and the results provided new evidences on the spatial stratification of microbial activities during each stage of the biofilm development. In addition, the impact of AO7 on nitrifying and denitrifying biofilm microprofiles was also monitored using microelectrodes. The responses of microorganisms to different AO7 toxicity levels were demonstrated in situ. The microbial activities measured using microelectrodes provided key information to bridge the gap between experimental observations and mathematical models. At macroscale, a series studies was performed to understand the fate of AO7 under aerobic nitrifying, anoxic denitrifying and anaerobic conditions in both biofilm and activated sludge systems. AO7 was found to be recalcitrant under aerobic conditions in both biofilm and activated sludge systems. The extent of AO7 removal in aerobic treatment processes was dependent on the biomass adsorption capacities. Under anaerobic conditions, AO7 was decolorized, and acclimated sludge was shown to be more efficient than unacclimated sludge. The presence of nitrate was found to inhibit AO7 decolorization under anoxic conditions. Batch reactors and continuous flow reactors were run to investigate the impact of AO7 on microbial nitrification and denitrification processes in both biofilm and activated sludge systems. The microbial responses to toxic shock were found to be different in the two systems. Enzyme inhibition models were applied to characterize the inhibitory mechanisms of AO7 on microbial activities. The results provided improved understanding of the complexity of inhibition phenomena in biological wastewater treatment systems.
Dr. Paul Bishop (Advisor)
1 p.
BIOFILM; MICROELECTRODE; NITRIFICATION; AZO DYE

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Citations

  • LI, J. (2001). AZO DYE BIODEGRADATION AND INHIBITION EFFECTS ON AEROBIC NITRIFICATION AND ANOXIC DENITRIFICATION PROCESSES [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1006802895

    APA Style (7th edition)

  • LI, JIN. AZO DYE BIODEGRADATION AND INHIBITION EFFECTS ON AEROBIC NITRIFICATION AND ANOXIC DENITRIFICATION PROCESSES. 2001. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1006802895.

    MLA Style (8th edition)

  • LI, JIN. "AZO DYE BIODEGRADATION AND INHIBITION EFFECTS ON AEROBIC NITRIFICATION AND ANOXIC DENITRIFICATION PROCESSES." Doctoral dissertation, University of Cincinnati, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1006802895

    Chicago Manual of Style (17th edition)

ucin1006802895
© 2001, all rights reserved.
This open access ETD is published by University of Cincinnati and OhioLINK.