Research Scientist II
Colorado State University
Dr. Andrea Hanson is a Research Scientist II at Colorado State University in the Department of Civil & Environmental Engineering. Andrea earned her Ph.D. in biochemistry and microbiology (2015) and B.S. in biochemistry and molecular biology (2009). Andrea’s research integrates microbial physiology & ecology, biogeochemistry, analytical chemistry, and engineering principles to understand the fate of contaminants in natural and engineered systems. She is currently working in collaboration with industry sponsors and academic colleagues to develop solutions for addressing substituted nitroaromatic compounds, per- and polyfluoroalkyl substances, 1,4-dioxane, perchlorate, and oil & gas produced water.
Combining Chemical and Biological Oxidation for Sustainable Treatment of Chloronitrobenzene in Anoxic Groundwater
Chloronitrobenzenes (CNBs) are chemical intermediates resistant to natural attenuation in anoxic environments. Advanced oxidation processes (AOPs) offer rapid responses to protect human and environmental health when potentially threatened by contaminants such as CNB, however, achieving mineralization is not often energy- and cost-efficient. Here we evaluated the applicability of combining an AOP (i.e. electrochemical oxidation) with biodegradation to mineralize CNB. We elucidated pathways and kinetics of CNB under varying electrolytic treatment conditions and identified multiple ring hydroxylation and ring opening products (e.g., dicarboxylic acids) that became increasingly harder to chemically oxidize as treatment time progressed. When AOP-treated water samples collected at different stages of electrochemical oxidation were exposed to microbial cultures derived from rhizosphere soil, ring opening products were completely consumed, whereas oxygenated ring products persisted. Our findings demonstrate that combining targeted chemical oxidation with biodegradation is an appealing approach for treatment of CNB-contaminated groundwater and likely other aromatic compounds.