Dr. Catherine Kirkland, research seminar - Investigations of biofilms in wastewater treatment
- Wednesday, March 27, 2019 from 3:00pm to 4:00pm
- Roberts Hall, 218 - view map
Multi-scale investigations of biofilms in subsurface and wastewater treatment applications
Dr. Catherine M. Kirkland, Montana State University
The interdisciplinary research discussed in this seminar focuses on investigations of beneficial biofilms at multiple scales for environmental engineering applications, including subsurface biofilm barriers for bioremediation, biomineralization to seal wellbore leakage pathways, and wastewater treatment. The talk will describe research applying low-field nuclear magnetic resonance (NMR) to detect 1) biofilm accumulation and 2) biomineralization in a radial-flow sand bioreactor. The NMR probe was also used detect biofilm accumulation and removal in a field study at an engineered field site in Butte, MT. The 275 kHz borehole NMR tool recorded changes in the T2 relaxation distribution where faster relaxation indicated biofilm accumulation in pore spaces. Conversely, the changed mineral surface of the biomineralized sand lead to an increase in T2 relaxation times.
Continued work on biomineralization has focused on up-scaling microbial growth methods for field application in subsurface wells. Three successful demonstrations have been performed recently: two were conducted in a water injection well to seal a leakage pathway accessing a high permeability thief zone located 30 – 50 feet above the perforations, and the third was performed in the presence of CO2-affected brine to seal a channel in well cement with applications for ensuring long-term geologic storage of carbon. These successful demonstrations bring this environmental biotechnology closer to commercialization where great potential exists to reduce emission of fugitive gases to the atmosphere and protect aquifers from hydrocarbon contamination.
Recent work explores the structure-function relationship in aerobic granular sludge (AGS), a biological wastewater treatment innovation comprised of spherical aggregates of biofilm. Since each granule (~2 mm) can simultaneously remove carbon, nitrogen, and phosphorus from wastewater due to substrate and oxygen gradients across the granule, AGS allows utilities to vastly reduce costs without sacrificing treatment efficiency. High field magnetic resonance imaging (MRI) at 950 MHz and 250 MHz identified micro-scale heterogeneous internal structures within granules where T2 relaxation rates and diffusion coefficients vary, but which do not appear to correspond directly to different redox zones. Ultimately, these results may help improve modeling for optimization of AGS wastewater treatment process design.
Finally, the talk will address future research efforts aimed at 1) identifying the origin and purpose of structural features observed with MRI in AGS granules and 2) applying low-field NMR to collaborative biofilm and biofilm-mineral research projects across the Department and the College.
Dr. Catherine Kirkland is an Assistant Research Professor in Civil Engineering, associated with the Center for Biofilm Engineering (CBE) and the Energy Research Institute, working on advanced mineral precipitation strategies to seal leaky wellbores. She is also in active collaboration with partners at TU Delft to study the morphology and activity of aerobic granular sludge sampled from full-scale Dutch wastewater treatment plants. She earned a PhD in Environmental Engineering from Montana State University as a member of the CBE and the College of Engineering Magnetic Resonance Lab. She was previously employed for nearly 5 years at Genesis Engineering, Inc where she worked primarily on subdivision plat applications, floodplain and septic permitting, and stormwater design.
- Civil Engineering