Two teams of chemical engineering students from Ohio University's Fritz J. and Dolores H. Russ College of Engineering and Technology tested their green design skills at the recent WERC Environmental Design Contest, held April 6-9 at New Mexico State University in Las Cruces, N.M.
The Waste-management Education and Research Consortium's contest tasks students with developing environmental solutions and demonstrating them with an operational bench-scale unit.
“The students gained a great deal from the experience,” said Dinos Professor of Chemical Engineering Darin Ridgway, the team’s advisor. “This was both from attacking a difficult open-ended problem from all directions, from dealing with technical, economic, and regulatory aspects, and from interacting with the judges who are mid- to upper-level technical professionals.”
Nineteen teams from universities across the nation competed, with the OHIO team tackling a challenge to remove ammonia from a wastewater stream containing dairy cow waste.
One team designed a two-step process to remove the ammonia, according to team member Courtney Paul, a senior chemical engineering major. In the first step, zeolite, a type of clay, was used to remove the ammonium ions by exchanging them with ions on the surface of the zeolite.
The second step in the design involved "regenerating" the zeolite so it can be used again. To do this, the system flushes a salt-water brine through the zeolite to exchange sodium ions for the ammonium ions. Then, ozone is bubbled through the brine, reacting with the ammonia in the brine to form harmless nitrogen, oxygen and water vapor. The zeolite can then be re-used to clean more wastewater.
The other team investigated the effect of the flow geometry on the power generated from a reverse electrodialysis cell. Energy is generated by flowing streams of different salt concentrations on opposite sides of ion selective membranes. The resulting diffusion of the ions produces an electric current. The team ultimately showed that changing the flow geometry increased the rate of diffusion.
“It was great to see all the different schools and the processes they designed,” Paul said. “Although we did not win anything, the experience itself was worthwhile. WERC is an opportunity for hands-on engineering experience as an undergraduate student.”