Can bacteria create green energy?

Most people would turn up their noses at anything to do with sewage. Hyung-Sool Lee smells opportunity.

“We need to do something for our future generations.  We need to change our traditional manner of dealing with waste-water treatment,’’ says Lee, an assistant professor in the Department of Civil and Environmental Engineering.  Lee also heads the Waterloo Environmental Biotechnology Lab, which looks at ways of getting more out of waste-water treatment than cleaner water and sludge.

Bug battery

Lee is currently looking at developing a microbial electrochemical cell - basically a bug battery that captures the electric power generated as bacteria metabolize waste.

Thriving on generous amounts of air pumped into waste treatment tanks, bacteria feed on suspended wastes in a typical waste-water treatment system. Undigested solids settle on the bottom of the system as sludge, and cleaner water heads down a pipe to the nearest stream.

As a profitable producer of large amounts of electricity, the microbial cell may not work, Lee says. But if the concept can be flattened into small wafers and stacked, it could lead to portable biological batteries that run on drops of organic material.

The large-scale cell can also be altered to produce such useful byproducts as hydrogen peroxide.

Human health applications

And, Lee adds, work with bacteria widens the possibility of other discoveries, including enzymes that may break down harmful deposits in another important circulatory system -- the human body.

Lee’s lab is also working on two other research projects:

• An anaerobic membrane reactor to break down waste using bacteria that function without pumped-in air. Lee estimates it costs about $1.5 billion a year in Canada to keep treatment plants aerated.

• A nutrient recovery system that operates much like a home water softener in that it runs water through a mineral core and has solution tank to recharge the core. The purpose is to recover nitrogen from the outgoing flow of cleaner water.

“My research philosophy is to learn nature, and to get nature to help us,’’ Lee says. “If we make bacteria happy, then bacteria can make us happy, too.”