From flush to flash, how septic systems could help power your home

Feb 27, 2014

A garbage compactor at the Flathead County Landfill.
Credit Flathead County Solid Waste

The Flathead County Landfill currently has a gas-to-energy project where methane gas is collected to power a generator instead of being burned off.

Waste management officials recently learned more about how to use the waste from septic tanks to make trash decompose faster, and produce more energy.

St.Clair County in Michigan has about 50,000-septic tanks- residences or businesses not hooked up to a sewer system and therefore using septic tanks to collect their waste.

Those tanks need to periodically be pumped.

The Landfill Director for St. Clair County Matthew Williams said a law banning septic haulers from field application of septage in winter months was one reason the County Landfill became the first septage bioreactor landfill project in the United States.

“It’s the marriage of two needs; we need to get that garbage decomposed, and take the benefit of the off-gas, septic haulers need a clean, easy place to put that septic tank waste, that’s environmentally safe,” Williams said.

The Smiths Creek Bioreactor Landfill Project started operating in 2008.

Basically, the landfill receives septage from haulers, it gets injected into the garbage. Williams said the trash is able to decompose 5-to-7-times faster, and produces more methane gas, and more energy for their generator.

To compare, Flathead County has 90,000 to St. Clair’s 170,000 people, and about half as many septic systems.

Flathead County Landfill Director Dave Prunty said for septage to be used at the Flathead Landfill the county would first need to work with the state Department of Environmental Quality on permitting.

Prunty said part of this would involve proving that adding septage wouldn’t cause problems.

“The biggest potential to impact groundwater or surface water is the introduction of water; whether that’s falling out of the sky, or we’re putting more water in there into the waste. So, the theory has always been that water is your enemy within a landfill. Now, this is a 180 degree change.

The next step would be the capital investment necessary to build a septage receiving facility and install pipes. This could come from disposal fees, waste fees, grants, or any combination thereof.

Williams came to the Flathead along with a representative from the engineering firm St. Clair County partnered with on their septage bioreactor project. They presented to county officials including the Solid Waste Board and County Commissioners and were sponsored by the Waste Not Project and the state Department of Environmental Quality.