Date of Completion


Embargo Period



Dr. Karl Guillard, Dr. Cristian P. Schulthess

Field of Study

Plant Science


Master of Science

Open Access

Open Access


Bioremediation and Phytoremediation Systems for Breaking Down Total Petroleum Hydrocarbons (TPH) in Contaminated Sandy Soil


The applications of bio- and phytoremediation systems were used to breakdown low-level total petroleum hydrocarbons (TPH) in a contaminated sandy soil. The overall aim was to determine which soil regimes, amendments, and plant species enhance the breakdown of TPH. The first project included planted mixtures of cool and warm-season grasses with different willows, mono and intercropped with various fertilizer and carbon additions. The second project introduced different soil regimes of saturation, intermittent oxygenation, installment of aboveground covers, as well as the addition of switchgrass and fertilizer. The reduction of TPH in both projects was measured by using gas chromatography, and indigenous microbes quantified by bacterial colony-forming units (CFU). Phytoremediation of low-level TPH contamination was observed in treatments with cool and warm seasons grasses and/or willow combinations, or through fertilization of the soil with NPK. The statistical analysis indicated that having plant species present with a fertilizer amendment was the most efficient method for breaking down aged TPH. There was no statistical significance between grasses and willows in their efficiency to degrade hydrocarbons. Furthermore, during the second experiment bioremediation was more advantageous than phytoremediation when the freshly spiked contaminant was added to sandy soils. Optimizing the system with soil amendments (soil moisture, air supply, and fertilizers) generated favorable conditions for breaking down TPH.

Major Advisor

Dr. Julia Kuzovkina