The researchers mixed the heat-treated soil with individual samples of glucose, sucrose, cellulose, lactate, potato starch and molasses. Fermentation of both glucose and sucrose with the heat-treated soil under slightly acidic conditions in the absence of oxygen produced high concentrations of hydrogen gas. Releasing the gas continuously during glucose processing resulted in 43 percent more hydrogen than when the gas was released intermittently.
Logan notes that wastewater from confectioners, canneries, sugar refineries, and other industries are rich in glucose and sucrose. "The conversion of the chemical energy in these sugars to electricity in fuel cells via hydrogen gas, provides a method for wastewater treatment and renewable energy production in one step. The greatest savings at treatment plants may result from reducing costs for aerators since aeration is the major operational expense at most wastewater treatment plants," says the Penn State researcher.
In addition, methane could also be generated via the same process and from the same materials to provide an additional source of clean energy for fuel cells.
Logan says, "Both hydrogen and methane production via fermentation could save money spent on aeration while at the same time making a wastewater treatment plant into a local power plant."
Van Ginkel notes that, "Generating hydrogen by fermentation is not new. Batch fermentation was used during World War II to produce industrial solvents for ammunition production. Small amounts of hydrogen produced early in the fermentation process were not recovered.
However, the industry later switched to steam reformation of petroleum to produce these industrial solvents when oil was cheap.
"Now, that oil has become more expensive, more efficient ways to generate hydrogen, for example the continuous fermentation processing method, may help us cross the barrier to realizing hydrogen
Contact: Barbara Hale