Biodegradation of petroleum compounds in soil by a solid-phase circulating bioreactor with poultry manure amendments

Abstract

Petroleum compounds account for the vast majority of contaminants in soils. Bioremediation is a widely accepted strategy in degrading these contaminants. This study demonstrates the effectiveness of nitrogenous nutrient (nitrogen) amendments in enhancing biodegradation of petroleum contaminants in soil by using a solid-phase circulating bioreactor (SCB). In a bench-scale SCB, total petroleum hydrocarbon (TPH) concentration (∼ 5000 mg kg^{− 1}) in soil decreased 92% within 15 days. In a scaled-up SCB system containing ∼ 120 kg petroleum-contaminated soil (TPH at ∼ 125,000 mg kg^{− 1}), a degradation rate of 635 mg kg^{− 1}d^{− 1} was obtained from the poultry manure-amended treatment during a 200-day period of operation. Treatments with the same amount of nitrogen (as ammonium nitrate) attained a TPH degradation rate of 469 mg kg^{− 1}d^{− 1} during the same period. Control SCB unit, which was maintained under the same aerobic conditions but not amended with nitrogen, had a TPH degradation rate of 273 mg kg^{− 1}d^{− 1}. Results from this study indicate that SCB can achieve significantly higher degradative rates than conventional landfarming (reported rates < 150 mg kg^{− 1}d^{− 1}) and poultry manure appears to be a preferred nitrogen amendment that can further enhance the biodegradation of petroleum contaminants in soils.

Keywords:

• Bioremediation
• petroleum hydrocarbons
• bioreactor
• poultry waste
• nitrogen amendment

Acknowledgments

We thank Mr. Ron Borgialli and Mr. Joel Mason for fabricating the bench-scale SCB, and Mr. Jesse Newcomer for constructing the scaled-up SCB units. We also thank Longmont Foods (Greeley, CO) for providing the poultry manure. We are grateful to Dr. Jeffrey Morris and Ms. Nennoa Bowsell for their review and edition of this manuscript. Financial support was provided by the United States Department of Energy (DoE) through Western Research Institute's Cooperative Agreement No. DE-FC26-98FT40322 with DoE. Any opinions, findings, conclusions, or recommendations expressed herein are those of the authors and do not reflect the view of the DoE.

This paper was presented at the SETAC Asia/Pacific 2006 conference held at Peking University, China on September 18–20, 2006.