Document Type

Thesis - University Access Only

Award Date

2006

Degree Name

Master of Science (MS)

Department / School

Civil and Environmental Engineering

Abstract

Extant respirometry was used to determine the Monod kinetic parameters of acetic acid, sucrose and ethanol. The activated sludge used for the experiments was obtained from a IO-liter bench scale sequencing batch reactor that was fed primary clarifier effluent with sucrose and acetic acid added during certain portions of the testing cycle. Three substrates were used in the extant respirometry tests. These included: acetic acid, sucrose and ethanol. A series of tests were run using each substrate. The yield (Y), maximum specific growth rate (μm), half saturation coefficient (Ks), and maximum specific substrate utilization rate (qm) were determined from the results of each test. The mean yield for acetic acid, sucrose and ethanol were found to be 0.719±0.036, 0.911±0.033 and 0.599±0.104 mg COD/mg COD, respectively. The average yield values for the three substrates tested in the current study were all higher than the typical yield range for wastewater. Ethanol is the only substrate that had some of its values fall within the typical wastewater range. Sucrose had the highest average yield followed by acetic acid, ethanol and wastewater, respectively. Ethanol had the largest range of yield values while the other three had similar ranges-approximately 0.15 mg COD/mg COD for each. The mean Ks for acetic acid, sucrose and ethanol were determined to be 0.280±0.195, 5.901±5.256 and 0.240±0.281 mg SCOD/L, respectively. The acetic acid and ethanol Ks values were significantly lower than sucrose and wastewater. This indicates that acetic acid and ethanol are more readily biodegradable than sucrose and wastewater The mean μm for acetic acid, sucrose and ethanol were found to be 0.041±0.013, 0.158±0.080 and 0.097±0.054 I/hr, respectively. The average μm values for the three substrates tested were all lower than the typical wastewater average values. However, some of the sucrose and ethanol values did fall within the typical range of wastewater values. The mean qm for acetic acid, sucrose and ethanol were found to be 0.058±0.020, 0.171±0.089 and 0.165±0.094 mg SCOD/mg ML SS-hr, respectively. The average qm values for the three substrates tested in the current study were all less than the average value for typical wastewater, although some sucrose and ethanol values did fall within the range of typical wastewater values. Sucrose and ethanol exhibited similar qm values and ranges. Acetic acid had the lowest qm and the smallest range of values. The kinetic parameters obtained for each substrate were determined to be in a reasonable range when compared to each other and to typical wastewater values. Furthermore, the acetic acid results were similar to acetic acid results measured by other researchers.

Library of Congress Subject Headings

Sewage -- Purification -- Activated sludge process

Microbial respiration -- Measurement

Format

application/pdf

Number of Pages

163

Publisher

South Dakota State University

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