Page 6 - Vol34No7 MarchApril2017
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LEBANON By Scott McRae
Blending Waste and Generating
Clean, Sustainable Power
The City of Lebanon (population The new plant began the commission- the treatment plant was
33,000) has embarked on a path forward ing stage in October of 2016 and will able to retire a very
to becoming more sustainable and provide nearly 200 kilowatts of clean power hungry digestor
environmentally conscious in its overall power for the wastewater treatment plant unit since the sludge is
waste disposal methods and reducing (half the total load) while diverting at being sent directly to the
its dependence on commercial landfills least 32 tons per day of waste material gasification unit.
as the primary option. Keeping the away from local landfills.
solutions financially self-sustaining was a In addition to
mandatory part of the project. A Partnership to Solve a Problem providing green
electricity, the facility
The city’s initial meetings with PHG Forming a public/private partnership has also supported
Energy in nearby Nashville led them to with local industries was key in making the growth of a partner, Rockwood
consider and implement the first stage the system financially attractive, according Recycling. Rockwood, located near the
of an overall waste-to-energy strategy: to PHG Energy spokesman and Chief plant, is fully engaged in the process and
combining municipal sewer sludge, Operating Officer Chris Koczaja. “Local receives the wood pallets and crates as
wood waste from local industries and companies were paying to have wood well as the tires. It grinds the materials
scrap tires from Wilson County into waste hauled to landfills. We developed a and prepares them to a 1" to 2" size
a biomass feedstock for gasification process whereby they paid tipping fees to needed for proper gasification.
and the conversion of resulting syngas the city to take the wood, lowering their
to electrical power utilizing Organic costs and providing excellent feedstock for There were additional good surprises
Rankine Cycle generators. our downdraft gasification plant.” Wilson in the feedstock gathering process. As
County decided that several hundred tons word spread to local industries that they
Mayor Bernie Ash has been excited of scrap tires they were paying to have could dispose of their wood waste in a
as the project has continued to exceed hauled away each year could also be sent green manner, the city found that there
expectations, especially from the to the gasification blend at considerable were more sources than needed to meet
financial perspective. The original intent savings. its 32 tons per day requirement. The
was for the project to break even. The proposed circle of outreach reduced from
project will actually create a positive The gasification plant is located on 42 miles to 22 miles. This saved the City
revenue stream for the city. “As this the site of the city wastewater treatment of Lebanon time and money when it
facility has come together, it has been facility, and the power produced is came to hauling materials for recycling.
a positive aspect for Lebanon as we are utilized “behind the meter” to offset The city made the decision to do its own
seeing visitors from across the nation as power previously purchased from the hauling, an additional savings that was
well as internationally,” said Ash. local utility. As an added financial bonus, not in the original business plan.
6 TPW March/April 2017
