Date of Award
Master of Science (MS)
James Castle, Committee Chair
John H. Rodgers, Jr.
Naphthenic acids (NAs) are a class of thousands of carboxylic acids associated with petroleum degradation. They become dissolved in oil sands process waters (OSPW) during the bitumen extraction process, and the resulting process waters can elicit toxicity to aquatic organisms. NAs are weakly biodegradable, but have half-lives of months to years, making it difficult to treat NAs with bioremediation. Two methods for promoting aerobic degradation (cometabolism and mycoremediation) were investigated as proof of concept for effectiveness in degrading commercial NAs. A reciprocating reactor inoculated with a white rot fungus, Pleurotus pulmonaris, was built and compared to an uninoculated reactor to determine the effects of this fungus on NA degradation. Inoculated reactors were more effective than uninoculated reactors in removing NAs, with zero-order half lives of 32 and 39 hours, respectively. This demonstrated the usefulness of both P. pulmonaris and a reciprocating reactor in promoting aerobic NA degradation. Cometabolic NA degradation using different substrates and substrate concentrations was investigated at bench scale. This study confirmed that cometabolic substrate addition increases NA removal rate in comparison to unamended degradation. It also showed that the concentration ratio of substrate to NAs affects the removal rate of NAs. This has important implications to the design of a constructed wetland treatment system for ecological risk mitigation of OSPW, where wetland detritus may serve as a cometabolic substrate to promote NA degradation.
Muller, Samuel Louis, "Mechanisms for Aerobic Degradation of Commercial Naphthenic Acids" (2016). All Theses. 2450.