American Society of Civil Engineers


Modeling the Effect of Ozonation on Acid Yellow 17 Dye in a Semi-Batch Bubble Column


by Laura W. Lackey, (Mercer University School of Engineering, Department of Biomedical and Environmental Engineering, 1400 Coleman Avenue, Macon, Georgia 31207 E-mail: lackey_l@mercer.edu) and Richard O. Mines, Jr., (Mercer University School of Engineering, Department of Biomedical and Environmental Engineering, 1400 Coleman Avenue, Macon, Georgia 31207 E-mail: mines_ro@mercer.edu)
Section: Environmental Engineering, pp. 1-9, (doi:  http://dx.doi.org/10.1061/40792(173)322)

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Document type: Conference Proceeding Paper
Part of: Impacts of Global Climate Change
Abstract: A pilot-scale ozonation process employing a semi-batch column was used to study the removal of acid yellow dye 17 from synthetic wastewater in a semi-batch bubble column. The effect of initial dye concentration on system performance was evaluated. This study utilized an 11.12-L, clear, PVC column that was filled with 8-L of tap water tainted with the acid yellow 17 dye for each experimental run conducted. Ozone was supplied to the system by sparging the gas through three porous stainless steel filters fixed in the reactor 0.15-m from the bottom of the column. The ozone supply rate was held constant at 3.78 L/min. Acid yellow 17 dye concentration (measured-as-A400), chemical oxygen demand (COD), five-day biochemical oxygen demand (BOD5) and the quantity of ozone utilized was measured as a function of ozonation time during each experimental run. Results indicate that ozonation is very effective at removing acid yellow 17 dye from synthetic textile wastewater. The biodegradability of the dye in the synthetic wastewater was evaluated by monitoring changes in BOD5 with respect to COD. The initial BOD5:COD ratio was 0.0083 and over time increased by an order of magnitude to a maximum ratio of 0.126 at 30 minutes. These results indicate that the biodegradability of the wastewater increased with an increase in ozonation time. Two-film theory was used to kinetically model the gas-liquid reactions occurring in the reactor. Modeling results indicated that during the first 10 to 15 min of ozonation, the system could be characterized by a fast, pseudo-first order regime. By combining a differential mole balance on the gas phase ozone concentration within the reactor with film theory, this initial period of the ozonation reaction was successfully modeled. With continued ozonation, system kinetics transitioned through a moderate then to a slow regime. Successful modeling of this period required use of a kinetic equation corresponding to a more inclusive condition. Model results are presented.


ASCE Subject Headings:
Water treatment
Ozonization
Acids
Wastewater management
Dyes