WSU develops new biogas process

RICHLAND — A Washington State University research team has developed a new method to treat sewage sludge and turn it into biogas – methane – that could help reduce the cost of waste treatment and help the environment, according to a WSU press release.

The process involves adding oxygen-rich, high-pressure steam to help break down and convert as much as 85% of the sludge to biogas, which can be burned in the same way natural gas is burned, to generate heat and electricity, the press release said.

Most wastewater treatment plants in the United States utilize an anaerobic digestion process in which bacteria, with no oxygen present, break down sewage waste. However, according to the press release, the process is inefficient and creates a fair amount of sludge, much of which is dried and carted to landfills.

The high-pressure steam is added before anaerobic digestion, the press said, allowing oxygen to act as a catalyst in breaking down complex molecules.

“This is not a very high-tech solution,” said Birgitte Ahring, an engineering professor at WSU. “It’s actually a solution that can be useful even at small scale. The efficiency has to be high or else you cannot warrant adding the extra costs to the process.”

WSU is working with Richland-area clean-tech startup Clean-Vantage to help further develop and commercialize the technology, which was funded through a grant from the U.S. Department of Energy.