Water and wastewater systems currently consume 3% to 4% of all electrical energy production in the United States, and upgrading wastewater treatment (WWT) plants to achieve nitrogen removal may double their energy demands. Nitrogen removal also may substantially increase emissions of nitrous oxide (N2O), a potent greenhouse gas. Biofilm systems are increasingly popular for upgrades to nitrogen removal. A novel biofilm approach is the Hybrid Membrane-Biofilm Process (HMBP), where cassettes of air-filled membrane-supported biofilms (MBfs) are integrated into an activated sludge tank. This eliminates bubbled aeration, potentially saving over 50% of the electrical energy requirements for WWT, while achieving nitrogen removal and potentially minimizing N2O emissions. Biofilms are dynamic systems, where physical dynamics (e.g., detachment) and chemical dynamics (e.g., varying substrate concentrations) can have important effects on biofilm structure, function, and overall performance. The goal of this research is to investigate the dynamic structure and function of biofilms for WWT.
The PI will develop a novel experimental approach that allows the study of physical and chemical dynamics of biofilm system using microsensors, bacteria tagged with a novel anaerobic fluorescent protein, and confocal laser scanning microscopy (CLSM). This allows near real-time analysis of the effects of detachment and shifts in substrate concentrations on the structure and function of biofilms. This technique will be used to study the effect of different modes of detachment (physical dynamic), and how this affects the structure and function of biofilms, especially as they relate to the HMBP process. The PI also will study N2O emissions in biofilms (chemical dynamic), and how they are affected by cycling of oxygen concentrations. Multi-dimensional, particle-based models will be developed to capture the dynamic effects.
This research develops a novel approach to biofilm research. The results will provide a fundamental understanding of the effect of detachment on the structure, function, and overall performance of biofilms. It is the first systematic study of N2O formation in biofilms, and of the dynamic structure and function of biofilms. It uses a novel combination of bacteria tagged with anaerobic fluorescent proteins, CLSM, and microsensors. Finally, it also develops a novel, particle-based, multidimensional model suitable for capturing these dynamic effects on biofilms.
The research will directly impact the understanding of detachment and N2O formation in biofilm systems relevant to WWT, including MBf-based applications. The proposed research platform can be used to study biofilms of clinical, industrial, and environmental relevance, such as biofilm viability after exposure to disinfectants, antibiotics, or heavy metals. The PI will focus on the training and education of Hispanic students to encourage them to pursue careers in science and engineering. High school teachers will be trained to use simple molecular tools and to develop teaching modules with assistance from high school students. A pilot undergraduate research exchange with Chile will be initiated as a means to provide an international research experience to undergraduate and graduate students. Graduate students also will be involved in international research collaborations. REU students will be recruited from Puerto Rico and local universities with large Hispanic populations
