iWWD - Waste-to-Energy Plant Provides Renewable Energy Source

Cost: $3.5 million
Location: Lebanon, Tenn.
Year: 2017-12-13
Size: 25,000 sq ft
Owner: Lebanon, Tenn.
Designers: Aries Clean Energy
Contractor: Applied Chemical Technology, Rose Construction, Groce Electric

Lebanon is a small but growing city in Middle Tennessee, just outside Nashville. According to a special census conducted in 2016, it is home to 32,732 people, an increase of nearly 20% over the 2010 population of 26,190.

Such growth reflects a healthy municipality, but it also can put a strain on local resources. A landfill that Lebanon uses to dispose of its municipal waste was nearing its capacity, so city officials looked into building a waste-to-energy plant that would reduce the amount of waste hauled to landfills and create a renewable energy source for the city’s wastewater treatment plant (WWTP).

Early economic projections for the plant were not encouraging, but when city officials expanded its scope to include hauling in waste from elsewhere—including local industries and other municipalities—and entered into a public/private partnership with Aries Clean Energy, the plant became a reality.

The innovative downdraft gasification plant opened in October 2016. It converts up to 64 tons of wood waste, scrap tires and biosolids per day into syngas, which is used to produce 1.8 kWh of electricity annually for the WWTP. The gasification plant’s process is projected to eliminate 2,500 tons of carbon emissions and keep thousands of tons of wood, sludge and tires out of landfills each year. In addition, it produces a carbon-rich biochar that will eventually be sold for a profit.

“The impact of the gasification plant has been very positive for Lebanon,” said Lebanon Mayor Bernie Ash. “We have business and industry leaders making inquiries and visits to see the facility. We encourage them to investigate this process to reduce their carbon footprints and landfill volumes.”

This initiative has garnered positive media attention from all over the world and reflects an ongoing commitment by the city to sustainable living. Lebanon also offers commuter rail service, employs natural gas-powered public works vehicles, and recently installed solar panel arrays to further reduce energy costs at municipal facilities.

“The Lebanon residents are proud to be part of a forward-thinking community that takes concern for our environment and lowers our energy costs at large,” said Sarah Hason, business development director for the City of Lebanon. “The gasification initiative has helped the Department of Economic Development as a recruitment tool, not only from the digital media exposure, but also the success of our private/public partnership with Aries Clean Energy.”

In addition to iWWD’s Top Projects recognition, the waste-to-energy plant was awarded the Tennessee Governor’s Environmental Stewardship Award for Energy and Renewable Resources.

“Statewide and national recognition by one’s peers for the waste-to-energy plant is reaffirming to say the least,” Ash said. “Lebanon is recycling and using renewable energy because it is the right thing to do. We are glad to serve as a working example of what can and should be done. The real winners here are the citizens of Lebanon who, because of this, live in a cleaner and greener community.”