The waste-to-energy technology, which will go on line early next year, is a downdraft gasification plant that will cleanly convert up to 64 tons per day of blended waste wood, scrap tires and sewer sludge into a fuel gas that will generate up to 300Kw of electricity. The generation of this power will provide for the plant’s internal power needs as well as contribute electricity to the wastewater treatment plant where it will be located.

“This is not incineration or burning,” Lebanon Mayor Philip Craighead explained. “There is no smoke or odor. The feedstock material is broken down at very high temperatures in a sealed vessel, and about 95 per cent of what goes into the gasifier comes out as the fuel gas.” (The remaining 5 per cent to 10 per cent of material exiting the gasifier is a high-carbon biochar that can be recycled or sold for agricultural or industrial uses.)

Tom Stanzione, PHG Energy president, said the Lebanon waste-to-energy project will deploy what his company believes is the world’s largest downdraft gasifier, adding: “This is the same basic technology we utilized in all our previous designs, and we have upgraded capacity and power density to accomplish a lot more gasification in what is not a lot more space.”

The 'large frame' gasifier, as the company refers to it, has been vetted through a rigorous testing process for more than two years at PHG Energy’s research facility. A standard PHG Energy gasifier can convert up to 12 tons of feedstock per day to fuel gas, while the Lebanon model will process up to 64 tons per day without substantially increasing the footprint of the plant, the company stated.
 

The waste-to-energy plant is projected to keep more 8,000 tons of material out of landfills each year – the equivalent of a line of trucks over 4 miles long. Carbon dioxide emissions will be reduced as well, keeping more than 2,500 tons out of the atmosphere each year. According to the Environmental Protection Agency, that equates to the CO₂ produced annually to provide electricity to 312 homes, or the annual Greenhouse Gas Emissions from over 450 passenger vehicles.

Funding of the $3.5 million capital cost has been obtained through a federal program that awards bond subsidies to local projects that conserve energy. Those Qualified Energy Conservation Bonds are allocated through the Tennessee Department of Environment and Conservation (TDEC), and repay communities about 70 per cent of interest expense.
 

The Lebanon waste-to-energy project will mark the 14th gasifier installation for PHG Energy. The company’s first municipal installation was commissioned in Covington, Tennessee, in 2013. Prior deployments of the thermo-chemical process were for industrial brick manufacturing clients to replace natural gas usage by cleanly converting wood waste to what is called producer gas or synthetic gas.