Commission Learns of New Landfill Bioreactor Tech

On Feb. 26, an official from Michigan visited the Flathead County Commission to give a presentation about a landfill bioreactor that uses sewage to help degrade waste.

Matthew Williams, the landfill director for St. Clair County in Michigan, explained how his county has integrated a septage bioreactor into one section of its landfill, which has led to increased waste degradation rates and stopped any sewage land application in the county.

Williams’ hearing came after a workshop series held by Citizens for a Better Flathead last week, which also featured Te-Yang Soong, the vice president of engineering at CTI and Associates of Detroit.

St. Clair County has about 160,000 residents, with roughly 30 percent of them on a sewer system. The rest use septic systems.

During their commission hearing, Williams discussed how the Smiths Creek Landfill has integrated the bioreactor into its landfill services. Trucks haul the septage to the landfill, where it is unloaded and stored underground until it is processed on site, solids removed, and then taken by closed pipes to one section of the landfill.

The fluid is injected into the dry garbage pile, which Williams said has increased degradation rates through moisture and microbial action, and has increased gas production in that part of the landfill.

The gas is then collected and sold to a gas-to-energy company, resulting in about $750,000 for the county per year, he said. That one section of the landfill, equaling about eight percent of the total waste, is producing 40 percent of the total gas produced there.

Flathead County currently runs a gas-to-energy program, in which the landfill gas collected is sold to Flathead Electric Cooperative.

Williams said his county paid for the bioreactor system through grants and loans, including a $13 million dollar loan which was reduced to $8 million through green project loan forgiveness, and a new $6 million loan that was cut in half through loan forgiveness.

The Michigan landfill also charges septic haulers five cents per gallon discharged at the landfill.

Dave Prunty, Flathead County’s solid waste director, said after the presentation that the science behind the septage bioreactor is exciting and it’s interesting to learn about cutting-edge technology in the solid waste sector, but a project like this would incur significant costs.

If Flathead County were to pursue such a project, Prunty said, the Solid Waste Board, the commission, and the health department would likely need a reason, such as wanting to eliminate land application for treated sewage.

Were that the case, then the county would probably start with approaching the Department of Environmental Quality about the project.

“They’re the body that oversees us and this is such a reversal of the technology, the dry-tomb theory, that certainly they’re going to be providing input on what a system like this might do up here,” Prunty said.

The “dry-tomb” approach means sealing garbage away from all air and water. Injecting septage into the dry garbage is a new concept, he said.

“I do think the solid waste industry is exploring this, a lot of the big companies are putting money into researching this,” Prunty said.

As for the Flathead potentially considering a bioreactor such as this, Prunty said there would have to be many more steps, including feasibility studies, before something like this could be a reality.

“It’s still a huge expense,” Prunty said.