The combination of beer, wastewater, microbes, fuel cells, high-school students and teachers sounds like a witches’ brew for an old-fashioned, illicit 1960s beach party.
Instead, these are the components that constitute the heart and soul of a new high-school science curriculum being developed by researchers at Washington University and two St. Louis area high-school teachers.
Lars Angenent, Ph.D., assistant professor of energy, environmental & chemical engineering, has received a $400,000 Career Grant from the National Science Foundation to develop microbial fuel cell (MFC) kits and an accompanying book of physics, chemistry and biology lessons. Eventually, he hopes to make them available to high-school science teachers as an exciting, visual, hands-on way to teach science.
As part of the grant, he will be working with Victoria L. May, assistant dean for Science Outreach in Arts & Sciences and director of the University’s Science Outreach program.
Using MFC technology, Angenent is treating wastewater donated by local brewery Anheuser-Busch Cos. Inc. and creating electricity in a six-liter device a bit bigger than a thermos. He uses a mixed medium containing thousands of organisms and optimizes environmental conditions to select for a bacterial community with improved electron transfer in anode biofilms, thereby increasing the electron transfer rate.
In addition, he plans to work with a single-culture biofilm to allow a full understanding of how to use operating conditions to manipulate electron transfer in anode chambers.
“Anheuser-Busch is supporting us not with money, but with wastewater, of which they have an ample supply,” Angenent said. “They’re very happy to be working with us because they have a keen interest in biofuels and bioenergy.”
Angenent also is working with teachers from the Hazelwood School District in north St. Louis County, one of the districts in the University’s Science Outreach program, to develop a curriculum using MFC.
“As a teaching tool, the MFC can enable the teaching of physics, chemistry and biology, all the while making the science exciting,” Angenent says.
“Students will actually be able to see the electricity their MFC is creating. If their MFC is being fed bacteria and sugars correctly, it will turn a light-emitting diode on. Imagine the excitement of that,” he said.
Angenent said that MFC technology offers advantages for converting waste to energy because the microbial fuel cells can operate using the dilute organic waste streams typical of domestic wastewater treatment plants and at low operating temperatures.
Angenent uses a carbon-based fiber on which biofilm grows, allowing him to connect two electrodes in the anode and cathode chambers with a conductive wire.
In contrast, in a hydrogen fuel cell, a membrane separates the anode and cathode chambers. When hydrogen meets the anode electrode, it splits into protons and electrons, with protons going across the membrane to the cathode chamber and electrons passing over the wire between electrodes to create a current. Oxygen is added to the cathode chamber, and on the electrode there is a reaction of electron plus proton plus oxygen to form water. Catalysts, such as platinum, are needed on both electrodes to promote the reactions.
“We are doing basically the same thing as is done in a hydrogen fuel cell with our microbial fuel cell,” Angenent said. “We’ve found that the bacteria on the anode electrode can act as the catalyst instead of platinum.”
With the Career Grant funding, Angenent intends to advance the conversion to electricity by predicting the power output of various configurations of microbial fuel cells by ascertaining the selection process for the microbial community in the cathode, thereby enhancing the electron flow, and by understanding how operating conditions can affect the biofilm at the anode.
The research will be integrated with an educational component that will engage students from the Hazelwood district and encourage them to consider careers in science and engineering.
The educational component will include the development of two new courses. One will be in bioprocess engineering for undergraduate and graduate students and will focus on how to transform waste into useful products. The second will be a molecular biology techniques laboratory class.
In addition to the two new courses, a program that engages high-school students in the science and engineering of microbial fuel cells has been established. Erin Roades and Brett Barron, chemistry/biology teachers at Hazelwood Central High School, are working on MFC kits.
They will bring their classes of 100-120 students onto campus once or twice each academic year to teach them using MFC lessons. Over the next two summers, Roades and Barron will compile a curriculum with the MFC as the centerpiece.
The lab classes will be conducted on the University campus, providing high-school students who might not have the opportunity a chance to learn about MFC and experience higher education. And from what Angenent and the teachers learn during the on-campus classes, teaching kits will be developed and refined that will allow extension of the hands-on learning to other high schools.
“We want to make the kits and curriculum available to a larger network beyond our Outreach connections,” Angenent said. “This way a rural school miles away from a University can still use the kits and concepts.”