CAREER: Microbial fuel cell technology for large-scale wastewater treatment

PI: Lars Angenent

NSF

Summary:

Conventional aerated wastewater treatment facilities consume substantial amounts of electricity to purify our domestic wastewater.  Anaerobic digestion of wastewater has been touted as the alternative to aerated systems, because energy is produced in the form of biogas while simultaneously purifying wastewater.  However, the diluted nature and the cold temperatures of domestic wastewater have limited the utilization of anaerobic digestion.  Microbial fuel cells (MFCs) can convert wastewater into useful energy - electricity.  They can do so at dilute organic concentrations and at low operating temperatures.  Therefore, MFC technology is an exciting and promising solution for treating wastewater.  To date, only very small MFCs have produced electricity because of fundamental limitations to scale-up.  My research program aims to address the limitations of current MFC technology by advancing the scientific understanding.

I will integrate MFC research and an educational program that has as one of its goals to help close the achievement gap between minority, urban high school students and their more affluent suburban peers.  I have proposed to use MFC systems as bait to capture the students' interest and imagination while teaching them the basic sciences.  Another goal is to train undergraduate and graduate students to solve environmental problems by integrating the latest molecular tools into engineering solutions.

Specific objectives.  I proposed three specific objectives in my research program: (i) to predict the effect of MFC configurations on power output; (ii) to ascertain the selection process for a microbial community in the cathode, which enhances electron flow; and (iii) to understand how operating conditions can alter the molecular properties of anode biofilms.  My background, combining reactor engineering and molecular biology, placed within the technology-intensive research environment of Washington University in St. Louis, gives me the unique position to achieve these objectives.

Broader impacts.  This work will directly promote the application of MFCs for large-scale wastewater treatment and bioelectricity production.  In addition, the conceptual framework of the research, the novel research tools, and the teaching program can be applied to other environmental engineering problems and other avenues of inquiry.  Two high school science teachers and numerous high school students will benefit from visiting our campus and being an integrated player in our research program.  The educational program targets teachers, and thus students, from school districts with a high percentage of minority students in the larger metropolitan area of St. Louis.  The proposed program broadens the participation of underrepresented groups in the process of scientific discovery.  Two doctoral students will enjoy a multi-disciplinary research and teaching milieu, which will give them the tools to solve complex environmental problems.  The combined research and educational program will contribute to a much needed paradigm shift in society and engineering: to treat waste not as a waste but as a resource.

Intellectual merit.  The scientific program aims to tackle a problem that is complex because it manifests at two scales: (i) a microbial scale; and (ii) a chemical/physical scale.  The interaction between the two scales is dependent on the transport and growth rates of cells and the transport and diffusion of electrons, protons, cations, and intermediate molecules, and therefore the differences between the two scales must be understood.  Our program will study both scales and their interactions by concurrent studies of bioreactor configuration and biofilm modeling (engineering), biofilm behavior (microbial ecology), bacterial metabolism (biochemistry), and genomic approaches (biology).  Such an interdisciplinary approach to problem solving can be applied to other multi-scale problems in biological systems.