Summary of Activities/Interests
Novel Nitrogen Removal Processes
Biological nitrogen removal is a major research area within the Nerenberg research group. Nitrogen from wastewater treatment plants and from agriculture runoff is a major contributor to the "dead zone" in the Gulf of Mexico, and also has led to widespread eutrophication (degradation) of waters throughout the world. New regulations are forcing wastewater plants to upgrade to nitrogen removal, often at great expense. Our goal is to create novel, cost-effective processes to reduce or eliminate nitrogen discharges, with additional benefits of reduction in energy and chemical requirements. The group has had three main research thrusts within this area:
1) Novel, membrane-based wastewater treatment processes.With funding from the National Oceanic and Atmospheric Administration (NOAA), via the Cooperative Institute for Coastal and Estuarine Environmental Technologies (CICEET), the Nerenberg group has developed a novel process for nitrogen removal from wastewater: the Hybrid Membrane-Biofilm Process (HMBP). The HMBP retrofits cassettes of O2-based MBfRs into activated sludge tanks. Nitrogen is biologically removed, while greatly decreasing energy requirements and chemical inputs. Our bench and pilot scale results suggest the HMBP has great potential for energy-efficient and cost-effective treatment. Research in this area is continuing, with funding from NSF and the WateReuse Foundation, on the fundamentals of biofilm development and detachment on gas-supplying membranes, and technology scaleup.
2) Denitrification of agricultural drainage. The Nerenberg group also is addressing nitrogen runoff from agricultural fields. Funded by a seed grant from NOAA (CICEET), and in collaboration with Dr. Tank's group in Biological Sciences, the group developed a novel biofilm process to enhance denitrification in agricultural headwater streams (drainage ditches), amending the streambeds with elemental sulfur (So). The So particles serve as an electron donor for denitrifying biofilms, greatly enhancing denitrification rates. This simple, inexpensive approach can greatly reduce nitrogen discharges from agriculture.
3) Greenhouse gas emissions from biofilm processes for wastewater treatment. Nitrogen removal processes may release significant amounts of nitrous oxide (N2O), a potent greenhouse gas. Little is known about N2O emission from biofilms. Microsensors for nitrate (NO3-), nitrite (NO2-), and ammonium (NH4+) are critical for this research, but they are not commercially available. We are one of the few labs in the country that fabricate these microsensors. With funding from NSF, we are exploring the kinetics and gene expression of the denitrification pathway as a means to understand potential reduction of exogenous N2O to N2 by denitrifying bacteria. With funding from WERF, we are looking at N2O and methane emissions from MBBR type biofilm processes for wastewater treatment.
Microbial Fuel Cells for Energy-Efficient Water and Wastewater Treatment
Microbial fuel cells (MFCs) are a novel technology that allows conversion of chemical energy contained in biodegradable compounds into electrical energy. MFCs have the potential to greatly increase the energy efficiency of water and wastewater treatment by harvesting energy while degrading contaminants. The research goal is to develop MFC processes for water and wastewater treatment, including nitrogen removal, especially integrating hollow-fiber membranes (HFMs) into the process. With funding from NSF, the Nerenberg group developed a novel and potentially transformational process where the MFC is layered onto air-supplying HFMs. In collaboration with the Verstraete group at the University of Ghent, Belgium, the group has shown that MFCs with a biological cathode can be used to concurrently remove nitrate and perchlorate. This may allow cost-effective drinking water treatment, and also may allow treatment of high-strength perchlorate wastes from military facilities.
Biofilm Treatment Processes for Drinking Water
More efficient water treatment methods are a critical need, especially in light of the poorer quality of water sources and increasing interest in wastewater re-use. Of particular concern are water micro-pollutants (e.g., endocrine disrupting compounds (EDCS), pharmaceuticals and personal care products (PPCPs)) that are not removed by conventional processes. The major research goal is to develop novel MBfR and other biofilm treatment technologies to remove micro-pollutants from water supplies. Our research has focused on biological degradation of perchlorate and bromate, two widespread drinking water micro-pollutants that are an endocrine-disruptor and carcinogen, respectively. Currently, we are collaborating with Dr. Picioreanu at the Delft University of technology (TU Delft) to develop a particle-based biofilm model of a spiral-wound MBfR for drinking water treatment. This model will provide a more basic understanding of the relationship between substrate concentrations, physical configuration of the spacer, biofilm development and detachment, and contaminant removal fluxes.
Novel Platforms for Biofilm Research
Biofilm research is typically limited to platforms where either the structure or function can be monitored non-destructively. The goal of this research is to develop new platforms to study the dynamic structure and function of biofilms relevant to MBfRs or to environmental, industrial, and clinical settings. In collaboration with my colleague Dr. Shrout, my lab has developed a new type of biofilm research platform that allows biofilms to be (1) grown under defined shear and substrate conditions, (2) probed with microsensors to determine substrate gradients and fluxes, and (3) viewed in near real-time using a confocal laser scanning microscope (CLSM). Key innovations in the proposed system include the use of a novel fluorescent protein that does not require molecular oxygen to fluoresce. Ours is the first environmental application of this "anaerobic" fluorescent protein, allowing visualization of target bacteria under denitrifying and other anaerobic conditions. The above platform initially can be used to study (1) biofouling on membrane filtration systems, (2) recovery of biofilms after exposure to disinfectants, antibiotics, heavy metals, or toxic nano-particles, and (3) colonization of established biofilms by pathogenic bacteria.
Ph.D., Northwestern University
M.S.C.E, Wayne State University
B.S.C.E., University of Buenos Aires
Dr. Nerenberg obtained his B.S. in Civil Engineering from the University of Buenos Aires, Argentina, in 1990. He worked as an environmental engineering consultant for eight years, and obtained his Ph.D. from Northwestern University in 2003. After a brief postdoctoral position at Northwestern University, he joined the department of Civil Engineering and Geological Sciences at the University of Notre Dame in 2004. In 2010, he received the National Science Foundation CAREER award for his research on biofilm processes. In 2012, he was the recipient of the Paul Busch award from the Water Environment Research Foundation.
Kelly Martin and Robert Nerenberg (2012). The Membrane Biofilm Reactor (MBfR) for Water and Wastewater Treatment: Principles, Applications, and Recent Developments. Bioresource Technology DOI: 10.1016/j.biortech.2012.02.110.
Joshua Shrout and Robert Nerenberg (2012). Monitoring Bacterial Twitter: Does Quorum Sensing determine the Behavior of Water and Wastewater Treatment Biofilms? Environmental Science & Technology 46(4) 1995-2005. DOI: 10.1021/es203933h.
Brenda Read, Jennifer Tank, and Robert Nerenberg (2011). Stimulating Denitrification in Agricultural Headwater Streams with Elemental Sulfur. Ecological Engineering. DOI: 10.1016/j.ecoleng.2010.12.007
Caitlyn Butler, Peter Clauwaert, Stefan Green, Willy Verstraete, and Robert Nerenberg (2010). Bioelectrochemical Perchlorate Reduction in a Microbial Fuel Cell. Environmental Science & Technology. 44:12:4685-4691. DOI: 10.1021/es901758z.
Caitlyn Butler and Robert Nerenberg (2010). Performance and Microbial Ecology of Air-Cathode Microbial Fuel Cells with Layered Electrode Assemblies. Applied Microbiology and Biotechnology 86:5: 1399-1408. DOI: 10.1007/s00253-009-2421-x.
Leon S. Downing, Kyle J. Bibby, Kathleen Esposito, Tom Fascianella, Ryujiro Tsuchihashi, and Robert Nerenberg (2010). Nitrogen Removal from Wastewater using the Hybrid Membrane-Biofilm Process (HMBP): Pilot Scale Studies. Water Environment Research 82:3: 195-201. DOI: 10.2175/106143009X426103.
Peter Clauwaert, Joachim Desloover, Caitlyn Shea, Robert Nerenberg, Nico Boon, and Willy Verstraete (2009). Enhanced Nitrogen Removal in Bio-Electrochemical Systems by pH Control Biotechnology Letters 31:10:1537-1543. DOI 10.1007/s10529-009-0048-8.
Bhoopesh Mishra, Maxim Boyanov, Shelly D. Kelly, Kenneth M. Kemner, Bruce A. Bunker, Brenda L. Read, Robert Nerenberg, and Jeremy B. Fein (2009). X-ray Absorption Spectroscopy Study of Cd Adsorption onto Bacterial Consortia. Geochimica et Cosmochimica Acta 73:15:4311-4325. DOI: 10.1016/j.gca.2008.11.032.
Kelly Martin, Leon Downingand Robert Nerenberg (2009). Evidence of Specialized Bromate-Reducing Bacteria in a Hollow Fiber Membrane Biofilm Reactor. Water Science & Technology 59:10:1969-1974. DOI: 10.2166/wst.2009.216.
Leon Downing and Robert Nerenberg (2008). Effect of Oxygen Gradients on the Activity and Microbial Community Structure of Nitrifying, Membrane-Aerated Biofilm. Biotechnology and Bioengineering 101:6:1193-1204. DOI: 10.1002/bit.22018.
Leon Downing and Robert Nerenberg (2008). Total Nitrogen Removal in a Hybrid, Membrane-Aerated Activated Sludge Process. Water Research 42:14: 3697-3708. DOI: 10.1016/j.watres.2008.06.006.
Margaret Dudley, Anna Salamone, and Robert Nerenberg (2008). Kinetics of a Novel Chlorate Accumulating, Perchlorate-Reducing Bacterium. Water Research. 42:10-11:2403-2410. DOI: 10.1016/j.watres.2008.01.009.
Robert Nerenberg, Yasunori Kawagoshi, and Bruce E. Rittmann (2008). Microbial Ecology of a Perchlorate-Reducing, Hydrogen-Based Membrane Biofilm Reactor. Water Research. 42:4-5:1151-1159. DOI: 10.1016/j.watres.2007.08.033.