Florida city to use sludge-to-energy gasifier

By Lisa Gibson
Posted June 2, 2009, at 12:26 p.m. CST

Sanford, Fla., will be the first municipality in the country to convert wastewater sludge to energy using MaxWest Environmental Systems Inc. gasification technology. The resulting syngas will be used to power the city's sludge dryer at the South Water Resources Center.

The city is leasing the equipment over the next 20 years from MaxWest, which will operate the system, and expects to save about $9 million on natural gas alone during that time. "That's the beauty of this project," said Charlie Turner, Sanford utility plant manager. "We didn't buy this. It's going to be a lot easier for us." The payments are about the same as the cost of purchasing natural gas, he added. Savings could amount to much more, as the city plans to look into using other feedstocks for the gasifier in the future, and possibly to produce electricity. "That would be very exciting," Turner said. "Who knows how much we could save."

Turner hopes the gasifier will be up and running in the next week. "We are just completing construction," he said. "We haven't actually run the unit except to test." The gasifier will consume about 30 to 40 cubic yards of biosolids-the end product of a sewer plant-per day to start with, working toward more. The facility will run 24 hours a day, producing 7 million British thermal units of renewable thermal energy per hour, according to MaxWest. Turner hopes other cities in the region eventually will contribute their wastewater sludge and other waste materials once the project expands.

MaxWest's gasification technology takes biosolids and feeds it into an enclosed primary gasifier to produce syngas. In a continuous integrating process, the syngas is oxidized in an enclosed thermal oxidizer to produce renewable thermal energy.

Besides saving the city money, the technology will be beneficial in disposing of dried residuals, which has been met with opposition from the public. Community members seem to be embracing the new process, Turner said. While Sanford is the first to commit to the gasifier, MaxWest is in discussions with other municipalities and industries in the U.S. and Canada, according to the company. The Sanford site will be a showcase for the technology, demonstrating is effectiveness, MaxWest says.
"We've got big hopes," Turner said. "We want it to be successful."