By TREY CHRISTY
trey.christy@newssun.com
SEBRING -- Since the Highlands County owned and operated asphalt plant opened in October, the Road and Bridge Department has paved or resurfaced six miles of the county's roads.
That number may not seem like a lot, but with each mile consisting of 650 tons of asphalt, and each ton using two gallons of fuel oil, that's more than a few taxpayer dollars -- roughly $20,000 -- in fuel alone.
The plant was opened at the landfill with the hope of harnessing the landfill's methane gas as a fuel source, which would essentially knock that cost down to $2,000.
The plant started using methane to churn out asphalt on Monday.
Gencor Industries Inc., which sold the county the plant, has been working around "computer issues" and started an air testing phase on Tuesday, said Ken Wheeler, director of solid waste for the county.
"They got it resolved last Thursday afternoon and today was the first day they could actually do some productions," Wheeler said Monday. "(Monday and Tuesday was) the first full air emissions test."
Testing air emissions is required by the Environmental Protection Agency.
The goal was to burn methane from the landfill all day during the testing process.
"I'm ready for this to happen and I know there are a lot of other people also," said Kyle Green, superintendent of the Road and Bridge Department. "This will kind of be the turning point or the do or die for the methane plant."
For Green's department, having the asphalt plant is already paying off.
"We can make it and lay it cheaper that what we can get from the private sector," he said. "It is a little cheaper, but the accessibility and availability far outweigh the other criteria."
He admitted that the price is still in the range of how much he can get the asphalt from the private sector, but the county will be saving $4 or $5 a ton, or roughly $3,000 per mile, when the plant uses methane.
"It's just one of those good feelings. We knew we could do it," Wheeler said about being able to use the methane. "There were some glitches, but Gencor engineers got it worked out and it's running fine."
The methane from the landfill can easily be used up in one day, but it is replenished over time.
"We are able to shut down our flare the night before and the concentration of methane increased," Wheeler said. "Then we draw it off during the day in the higher concentration."
The plant is able to run at different production speeds, further compensating for the amount of methane available in one day.
"We can vary how many tons (of asphalt) come out to match our landfill gas capacity," Wheeler said. "We can slow it down, adjust it, and get the most from the landfill gas and minimize the use of fuel oil."
The maximum rate of production is 200 tons per hour. That can be cut to 50 tons per hour if necessary.
Asphalt consists of asphalt cement bonded to sand, stone and "screenings," or very coarse sand. The fuel is used to dry the materials before they are bonded to the asphalt cement.
Currently the landfill produces enough methane to aid production of 1,060 tons of asphalt per day, Wheeler said.
With just under 1,000 miles of paved roads in Highlands County, the plant count effectively be used to pave every road in the county in three-year cycles.
"Typically you will get 20 to 25 years out of a road," Wheeler said. "So if we wanted to do it on a 25-year life cycle we would need to pave 40 miles every year."
If the plant produced 650 tons of asphalt each day it was open -- enough to pave one mile of road -- it could operate less than once a week using methane as the major fuel source.
Tuesday, February 17, 2009 - www.newssun.com/0218-tc-aspalt-plant