All ETDs from UAB

Advisory Committee Chair

Robert W Peters

Advisory Committee Members

James F Cruise

Joseph J Gauthier

Jason T Kirby

Kathleen M Leonard

Document Type

Dissertation

Date of Award

2012

Degree Name by School

Doctor of Philosophy (PhD) School of Engineering

Abstract

Diesel engines are the work horses of industry and transportation. Pervasive diesel fuel use impacts stormwater, by increasing petroleum releases to surface waters. Sump containment of diesel-adulterated stormwater commonly keeps diesel from contacting surface waters. Once contained, the quandary lies in effective stormwater treatment that allows discharges within the local watershed. On-site treatment of diesel sump water ordinarily involves gravity oil-water separation technologies. These technologies' treatment times range from hours to days. Commonly, they cannot meet National Pollution Discharge Elimination System (NPDES) stormwater discharge standards for oil and grease because they best remove `free' oil not commonly occurring emulsions. Oil-water gravity separation treatment is least effective during intense stormwater run-off events. An on-site, rapid, cost-effective treatment technology of diesel sump water is lacking. This research initiated the determination of sonication's potential to treat diesel laden stormwater. Sonication effectively oxidizes and pyrolyses a broad range of hydrocarbons in aqueous solutions, groundwater and soil. A mass balance, using gravimetry and chromatography, determined the physical-chemical fate of diesel range organics (DRO). The rate of DRO decrease per sonication time was assayed. A preliminary assessment of the cost effectiveness of sonication treatment relative to oil-water gravity separation technology was compiled. Bench scale sonication results from an initial 203 mg/L diesel fuel concentration achieved NPDES oil and grease discharge levels within 10 minutes. Sonication of diesel fuel in water produced carbon monoxide, short-chain hydrocarbon gases, short-chain hydrocarbons in aqueous solution, solid hydrocarbon precipitates, and residual diesel range organics. Sonication was more energy intensive per mass treated than oil-water gravity separation. However, sonication's potential to eliminate peripheral costs required by gravity oil-water separation technology may prove cost effective. This research indicates sonication decreases the concentration of diesel in water through combustion and the lytic and synthetic reactions of diesel range organics. Complex diesel component interactions prevented generation of a predictable rate model. Sonication is 5-1265 times more energy intensive than a belt stripper type oil-water gravity separator. However, sonication may be cost competitive due to the decrease in regulatory and operating costs compared to belt stripper technology. A pilot-scale investigation would better test sonication's treatment potential.

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