Within the next five years, sewage and other types of wet waste could produce enough energy to power cars, homes, and factories. A team headed by Ashok Bhattacharya, director of the process technology group at England's Warwick University, has developed a method of pulling hydrogen gas from sludge and other wet biomass-hydrogen that can be used in fuel cells. "The 'wet' is the innovation," he says. Dried wood pulp and other biodegradable stuff has been used to produce hydrogen for years. But according to Bhattacharya, wet biomass yields about twice as much of the gas.
The process begins by harvesting hydrogen from water in the solid waste. Next, carbon monoxide, carbon dioxide, methane, steam, and some hydrogen are extracted. These gases are then fed into a reactor that splits the steam and methane molecules apart to get even more hydrogen. A semipermeable ceramic membrane allows only the hydrogen to pass through. The membrane also provides hydrogen that is 95 percent pure.
The European Union has given Bhattacharya and colleagues a grant of about $3.6 million to build a large-scale prototype of the gasification unit and reactor in either England or Holland. He hopes it will be complete within the next three years. Similar systems could eventually be built right into sewage plants, paper mills, or livestock farms to provide electricity. The next challenge, says Bhattacharya, is to find an economical way to incorporate fuel cell technology and waste-gasification systems into individual homes and residential communities-thus powering our lives with our own waste.
-Sunny Sea Gold