Degradation Rates for Petroleum Hydrocarbons Undergoing Bioventing at the Meso-Scale |
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Authors: | Alamgir A Khan Richard G Zytner |
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Institution: | School of Engineering , University of Guelph , Guelph , Ontario , Canada |
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Abstract: | ABSTRACT Bioventing can be effective for the remediation of soil contaminated with petroleum hydrocarbons. However, implementing laboratory results in field scenarios is difficult due to the lack of scale-up factors. Accordingly, laboratory bioventing experiments were undertaken at the meso-scale and then compared with previously completed micro-scale tests to evaluate the important scale-up factor. The developed meso-scale system holds 4 kg of soil, with bioventing conditions controlled from a nutrient, airflow, and water content perspective. Three soils were tested, and categorized as loamy sand, silt loam, and a mixture. Results over a 30-day period showed a two-stage degradation pattern that encompassed first-order degradation rates as compared with the single-stage first-order degradation rate determined in the micro-scale study. For the first stage (0–8 days), the degradation rate for loamy soil was 0.598 day?1, with the silty soil at 0.460 day?1, and mixed soil at 0.477 day?1. After 8 days, the degradation rate constant for the loamy soil dropped to 0.123 day?1, with the silty soil dropping to 0.075 day?1, and the degradation rate for the mixed soil dropping to 0.093 day?1. Comparison of the measured degradation rate values with the results from the micro-scale experiments gave scale-up factors varying from 1.9 to 2.7 for the types of soil considered in the current study. These differences in degradation rates between the two scales show the importance of scale-up factors when transferring feasibility study results to the field. |
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Keywords: | biodegradation rate bioremediation gasoline scale-up factor soil remediation TPH |
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