The city of St. Petersburg has a $2.5-million federal grant to design a waste-to-energy facility. The new $42-million plant will turn 35,000 tons of sewage a year into natural gas and clean, high-grade fertilizer.
"This gas will be cleansed, and then used to run gas generators which will then power our treatment plants, thereby offsetting several million dollars in electricity expenses," the city's Mike Conners explained.
Conners added excess natural gas might be used to fuel the city's 73 sanitation trucks.
"Next week we will have two compressed natural gas trucks arrive at our sanitation shop and we will monitor how well they perform over the next six months," Conners said. "If they perform as expected, we are then going to commit over a multi-year period to convert our fleet from running off of diesel to run off of compressed natural gas."
He estimated that could save the city an additional $3 million a year.
Currently, the wastewater sludge is trucked to farm fields and used as fertilizer. But concerns about stormwater runoff have spawned new environmental rules, effective January 1, 2013.
"The new regulations are eventually going to eliminate that disposal operation altogether," Conners explained.
St. Petersburg will be granted some leniency since it is developing an alternative disposal method.
The new process will leave some solids but Conners does not foresee environmental constraints.
"When you digest sludge, you're essentially burning off all of the volatiles," he continued. "So you're separating the bad stuff from the remaining good, organic stuff."
Conners predicted the fertilizer will be made available to the public free of charge.
The design phase of the project should take a year and a half, followed by two to three years of construction.
FOX 13 / WTVT-TV
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