by Joni Astrup
Great River Energy achieved a milestone in October 2011 for the first time in the history of the garbage-to-electricity project in Elk River: It didn’t send any garbage to a landfill.
While plant officials can’t promise they’ll never have to landfill again, for the past six months nothing has been landfilled.
“Since September we’ve been working really hard to hold it at zero landfilled. We’ve been really happy with that,” said Steve Vrchota. He is the leader of plant operations at Great River Energy’s Resource Processing Plant in Elk River.
Garbage from Sherburne County and surrounding counties has been processed into fuel since the project went online in 1989. Currently about 250,000 tons of garbage a year from Sherburne, Anoka and Hennepin counties are trucked to the processing plant at 10700 165th Ave. in Elk River. There it is sorted, recyclable materials are pulled out, and the garbage is processed into a fluffy fuel known as refuse-derived fuel or RDF. That RDF is then trucked to the Great River Energy power plant at 17845 Highway 10 in Elk River, where it is burned to generate electricity.
The power plant produces 33 megawatts of electricity — enough to provide power to about 25,000 homes.
Changes at the plant
For the first 20 years of the project, about 83 percent of the garbage that came into the processing plant was turned into RDF, Vrchota said. Four percent was recycled (primarily steel and aluminum) and 12 percent ended up being landfilled. It included a dense residue that was left after processing as well as bulky items like mattresses and pallets.
But all that began changing after Great River Energy purchased the processing plant in April 2010.
Great River Energy began implementing changes to reduce the amount of garbage that was landfilled and increase the amount of RDF produced and recyclable metals sold.
“Most of the solutions actually came from all of the people who already work in here (at the processing plant),” Vrchota said.
As a result of the changes, now 94 percent of the garbage becomes RDF. More recyclable metals are being pulled out of the waste stream and diverted from the landfill.
What made this possible?
One of the changes was adding a bulky waste shredder. Great River Energy initially rented one and then bought its own unit, which became fully operational in March. It shreds things like mattresses, box springs and pallets. Shredding allows the plant to recycle things like steel in those bulky materials and process the rest into little pieces of RDF.
The change is saving Great River Energy more than $300,000 a year.
Tim Steinbeck, Elk River Resource Recovery Project manager, said by putting bulky materials in the bulky waste shredder, they can reduce the size of those materials so they will go through the processing plant. “We can remove the metals out of it so we have a higher percentage of metal recovery. And we avoid all of that material going to a landfill,” Steinbeck said.
Another change is a new ferrous metal cleanup system. This material previously contained about 65 percent steel and was sold for about $90 a ton. Now the product contains 85 percent steel and sells for about $250 a ton. Between not having to landfill material and getting a higher rate, the net increase in revenue to the project is approximately $1 million a year. About 7,800 tons of ferrous metal are recycled a year.
A third change is residue reprocessing. This is the residue left after the garbage is processed into RDF. In the past it was landfilled at a cost of about $500,000 a year. Now it is run through the plant a second time. As a result more of the residue is turned into RDF and more metals are recovered. What’s left has enough valuable metals concentrated in it that it can be sold rather than landfilled.
The fourth change involves aluminum recovery. Fine tuning the system has allowed the plant to pull out more aluminum from the garbage and increase revenue by about $150,000 year.
Some materials that used to be landfilled are now being recycled including license plates, aluminum and stainless steel pots and pans as well as brass and copper in faucets, stainless steel sinks, and copper and steel found in motor windings from mixers, hand drills and so forth. More copper and heavy ferrous are also being recycled.
“It helps us with our costs, and you’re not sending useful material to a landfill,” Vrchota said.
He said they can’t guarantee they won’t ever send anything to a landfill again, “but we’re certainly trying to do our best to get as close to zero (material landfilled) as possible,” he said.
Plant looks at recycling golf balls
Ever wonder what happens to that golf ball you toss in the trash?
Chances are it ends up in a large container at Great River Energy’s Resource Processing Plant in Elk River, which turns area garbage into a fuel used to produce electricity.
“We get about a hundred a week,” said Steve Vrchota, leader of plant operations at the plant.
The golf balls are being collected and efforts are underway to find a place to recycle them.
About Great River Energy
•Great River Energy (GRE) is a consumer-owned, not-for-profit electric utility.
•GRE is owned by its 28 member cooperatives for which GRE generates and transmits electricity. The members are located in the outer-ring suburbs of the Twin Cities up to the Arrowhead region of Minnesota and down to the farmland region in the southwestern portion of the state.
•GRE’s member cooperatives distribute electricity to approximately 645,000 homes, businesses and farms.
•GRE is the second largest electric power supplier in Minnesota and one of the largest generation and transmission cooperatives in the country.
•To learn more about the Elk River Resource Recovery Project, go to www.youtube.com/watch?v=XQ5jIwyz6nI to see a seven-minute video.
Source: Great River Energy