15 October 2009
Sewage the new 'black gold'
A Massachusetts-based Ethanol company and a recycling company out of Israel formed a partnership to use sewage as a feedstock for making ethanol.
These days, more and more companies are finding that sewage is a veritable “black gold.” In recent years, sewage sludge has been mined for electricity, fertilizer, fish food, and gasoline. And while others have worked to produce ethanol from municipal solid waste, sewage from wastewater has been a relatively unmined ethanol source.
Technology Review reported the cellulosic ethanol company Qteros, in Marlborough, Mass., and Applied Cleantech (ACT) are combining technologies to turn sewage into ethanol biofuel. According to the companies, the process could produce high-quality biofuel while cutting down on monthly bills at wastewater treatment plants.
Jeff Hausthor, Qteros cofounder and senior project manager, said the recycling process uses solids from wastewater treatment as its primary feedstock—a material that facilities usually pay to have trucked away to landfills or used as fertilizer. “Given the feedstock has a negative cost, it is going to save every municipality money while they’re generating energy from something they needed to throw out before,” said Hausthor.
Sewage makes sense not just from an economic standpoint but also from a scientific one, according to Jim McMillan, a principal biochemical engineer at the National Renewable Energy Laboratory who is not involved in the project. One of the major steps in cellulosic ethanol production involves breaking down plant matter and separating cellulose from its tough lignin shell, either by mechanically shearing the material or by treating it with harsh chemicals. In contrast, the sewage that streams in from sewer pipes contains plant matter that is high in cellulose and low in lignin.
For related information, go to www.isa.org/environment.