PhD student recognized for work in groundwater remediation

Veronica Lima Gonsalez received an award for her research paper from consulting firm Geosyntec.
Tufts Department of Civil and Environmental Engineering PhD student Veronica Lima Gonsalez.

Veronica Lima Gonsalez, a doctoral candidate in the Department of Civil and Environmental Engineering was awarded third place in a student paper competition by Geosyntec, which is a consulting and engineering firm that works on problems involving environment, natural resources, and civil infrastructure. Her paper titled “Process-based Model to Describe Treatment of Nitrate-rich Groundwater” offers a framework that engineers may use to improve efficiency when cleaning up groundwater contaminated with nitrate, which often happens in areas with septic systems and fertilizer use. 

In her paper, Gonsalez explores how denitrification in groundwater is an effective way to tackle the problem. The denitrification process involves underground bacteria breaking down nitrate into harmless nitrogen gas. Gonsalez used a detailed computer model to better understand the duration and effectiveness of treatments that aim to stimulate indigenous bacteria using vegetable oil.  For this modeling, she employed the Activated Sludge Model (ASM) framework, which is commonly used to model wastewater treatment facilities where denitrification is engineered to occur, within a model used to describe groundwater flow and transport.

To assess denitrification's effectiveness, Gonsalez utilized data from column experiments using columns filled with soil and groundwater and to which vegetable oil was added. She also compared her detailed model with a simpler one used in groundwater remediation. Her findings revealed that her detailed model outperformed the simpler one, particularly in predicting how long it would take to clean up the nitrate and how much nitrate would remain in the water. By adjusting two parameters in the model, such as the yield coefficients for nitrate and nitrite, she was able to further improve its accuracy.

Gonsalez continues to explore using denitrification to decontaminate groundwater, working under the supervision of Associate Professor Andrew Ramsburg. Gonzalez, Ramsburg and their collaborators have recently published research in Water and Environmental Engineering Science. Gonsalez’s work contributes to our understanding of how to remediate nitrate-contaminated groundwater using carbon sources like soybean oil, and provides a valuable tool for engineers and others involved in designing and implementing cleanup strategies, making them more effective and environmentally sustainable.