The incinerator at the Dillingham landfill has been clean-burning trash for a little over a year now.
While it’s doing a good job of cutting down the volume of material that gets buried in limited cell space, it’s not proving as cost efficient to operate as hoped.
The Pennram incinerator needs diesel fuel to operate, mainly to get up to temperature.
Then the burning waste can heat the machine to keep burning more waste, but how well that works depends on what trash is going in.
Public Works Ken Morton director broke down the costs for the city council at a recent workshop.
“So in the first year of operation, the incinerator has consumed about fifty thousand gallons of fuel oil,” Morton said. “(That) works out to about 200 gallons a day, and at the current bid prices, it’s a little over $400 a day to run it, and about $100,000 per year in fuel to operate it.”
That’s way past what the city had hoped it would spend when it started shopping for an incinerator in 2014.
Models that burned that much diesel were deemed to costly to operate.
The Pennram model, however, was supposed to operate on 60 to 70 gallons of diesel per day, and maybe less when the waste stream was high.
A company technician recently audited Dillingham’s unit, and told Morton part of the problem is with Dillingham’s trash.
“In general our waste has a higher moisture level, and has a lower thermal value as well,” Morton said. “He made the comment that our waste stream seems to have a higher percentage of household waste in it than he’s used to seeing, and less commercial waste. And as a result it does not create as much heat when it burns.”
The other problem with the waste stream is Dillingham is not doing a good job of sorting out what’s not supposed to go in.
“There’s glass, there’s aluminum, there’s cans,” he said. “We pull out a surprising number of propane cylinders; they seem designed to jam up the conveyor system.”
The glass melts and can block the burners.
Aluminum melts and can fill the air injection ports.
These problems bring the burning efficiency down, and every time the incinerator has to be turned off, it takes dozens of gallons of diesel to get back up to temperature.
“The lack of sorting of the refuse is a substantial challenge to its operation,” he said.
A lot of the trash that comes in from a local refuse company has not been sorted, and it’s also been compacted, making it more challenging on the staff to sort.
Most other bagged garbage isn’t coming in separated either.
Morton suggested when landfill rates come up for renewal next year, the city consider incentivizing better trash habits.
“If you show up for example with your trash and you do the Boy Scout’s honor that it doesn’t have aluminum cans, doesn’t have glass, it would be beneficial for that to be reflected as a much lower price than if somebody brings in waste that does not have that assurance,” Morton said. “I’d like to encourage to where we’d could get a balance that’ll run through the incinerator better, and that which does not, we’ll run that to the open cell.”
Public Works is still looking at other variable, such as how many hours a day and days a week it should operate outside of the summer peak, when even at 24 hours a day it couldn’t keep up with the incoming trash.
There’s a tough balance between paying staff to keep it running and paying for fuel to restart it after stopping.
Burying trash isn’t cheap either.
Morton estimates it can take about 20 cubic yards of covering material per day, at a cost of roughly $225 per day.
He said the landfill’s active cell should have space through the the winter.
Work on an expansion cell is underway.
Morton said he would keep crunching the numbers and look for more options on how to best burn and or bury the town’s trash.