Humans, automation keep new recycling center humming along
November 11, 2012 - Updated: November 12, 2:32 p.m.
Homeowners and businesses are into their second month of the area’s largest single-stream recycling effort after Spokane City Hall spent $3.4 million to buy thousands of the new 64-gallon blue recycling carts.
So far, the results prove one thing: Area residents are throwing more items into the new carts. That’s exactly what government officials and the operator of the new recycling facility on the West Plains were counting on.
A single-stream system lets residents toss a greater variety of recyclable items into taller carts. The older system required residents to separate and sometimes bag recyclables, then place them into 18-gallon curbside bins.
The new system means residents can easily recycle much of their household waste that used to go into the trash.
The first step in a cost-effective single-stream system was the opening of the new Waste Management MRF, or “murf” – the industry term for a materials recycling facility.
Houston-based Waste Management invested close to $18 million to build the new 50,000-square-foot center just west of the regional Waste-to-Energy Plant on Geiger Road. The company paid for the project without any public money.
Waste Management calls it the SMaRT – Spokane Material and Recycling Technology – Center.
It began processing solid waste Oct. 4. By the end of the month it had processed 4,000 tons, coming from Spokane, Spokane Valley, Liberty Lake, Airway Heights, Coeur d’Alene, Post Falls and Sandpoint.
“The name of the game in solid waste is to get more single-stream bin participation,” said Chaz Miller, a director with the National Solid Waste Management Association.
Giving customers access to single-stream recycling provides a range of benefits, Miller said. Not only can customers cut their garbage bills; the system reaps profits for companies like Waste Management and cuts operating costs for budget-strapped cities.
Before October, Spokane residents and businesses were putting about 1,000 tons of recyclables into curbside bins each month. In October, Spokane’s monthly load grew by 250 tons.
That’s just the beginning, according to Matt Stern, Waste Management’s director of recycling operations for the Northwest.
As it expands, the recycling facility will be able to process more than 100,000 tons per year, Stern said. That extra waste will come from across the region.
Other areas, including Richland and some cities in Montana, are looking to do the same, Stern said.
How it works
The West Plains MRF relies on a crew of 35 employees who run the automated equipment that separates and bundles piles of glass, metals, aluminum, paper and other materials.
The facility now operates one 10-hour shift. As cities bring more truckloads to the tipping dock, the goal is to run two 10-hour shifts, with four hours set aside for cleanup and maintenance.
After trucks dump the collected waste at the back of the plant, an automated feeder begins to push and collect the piles into a drum feeder. That system starts lifting material onto a conveyor system that rises about 20 feet off the plant floor.
The horizontal conveyor – about 28 inches wide – travels from the back wall of the plant along a long side wall.
Next, a team of four workers presort the fast-moving stream, which goes by at 6 feet per second.
Their job is to remove items that don’t belong, tossing them into bins or sorting tubs on either side of the belt.
Any plastic bags are plucked off the belt and fed into overhead suction tubes that whisk them out of the system. The bags make up about 5 percent of processed material that ends up as residue with no value.
The presorters also remove Styrofoam, wires, chains or medical waste that sometimes show up in the stream.
“We get a variety of things people shouldn’t be putting in,” Waste Management’s Stern said. It’s common to have to remove diapers, car batteries, plants and clothing.
“They have to all be pulled off,” Stern said, adding that the presence of nonrecyclable items is just part of the business.
The previous curbside system didn’t have that problem. Truck drivers hand-sorted the items in the bins, removing those items that weren’t processed by Spokane Recycling and Pacific Steel & Recycling, where the city formerly took recyclable waste.
With single-stream containers, the burden falls on Waste Management’s expensive automated systems and its workers, Stern said.
After presorting, the material goes through a number of disk screeners. The sturdy plastic disks rotate constantly, mechanically separating flat cardboard and paper items from containers and cans.
The flatter items, such as cardboard, paper and newsprint, bounce upward and are pushed onto one belt. The heavier containers fall onto another belt, ending up on another conveyor.
Stern said that’s the key principle behind the automation: “The whole process is generally a continuing refinement in separating two- from three-dimensional items,” Stern said.
Over the next 15 to 20 minutes, the materials on belts keep moving across the building.
At nearly every step workers stand next to the belts, watching and removing items that don’t belong.
The equipment, when it works correctly, keeps taking some items off the belt, creating smaller groups of aluminum, tin, steel, cardboard, paper and plastic.
Since PET (polyethylene terephthalate) plastic – the kind used to bottle most sodas and liquids – has a higher recycled value, it’s segregated from other plastics.
When the plastics conveyor reaches a point in the facility halfway from the starting point, it passes over an optical scanner.
The scanner sends precisely timed infrared beams from below the belt, trying to spot items made of clear PET plastic.
When it spots one, it sends a signal to another device a few feet forward along the belt. The signal causes pressurized air to blow upward, blasting the PET item onto a secondary conveyor belt.
All the separate streams finally fall from the conveyors down chutes into 30-foot-long metal containers, or bunkers.
A plant operator monitors the loads going into the bunkers. When a container is filled, the system will automatically move it toward baling machines in a corner opposite from where the items first entered the building.
Once baled, the bundles of paper, plastic, metal or cardboard are shuffled outside toward the shipping dock. Depending on where prices are best, Waste Management sends them to locations across the region, Stern said.
He said the West Plains site, one of more than 100 single-stream facilities it operates, can process about 250 tons of recyclables per 10-hour shift.
In addition to saving natural resources by diverting more items into reprocessing, Spokane’s contract to send more material to Waste Management makes sense for city taxpayers, said Spokane’s solid waste director, Scott Windsor.
The city has a 10-year contract with Waste Management. In exchange, Waste Management has exclusive rights to the city’s roughly 65,000 residential customers. Those residents are not required to use the larger single-stream bins.
Spokane’s business and commercial customers can choose to use the city’s waste management service or any other private recycler in the area.
City residents aren’t paying any more than they did for the smaller bins. Many residents, Windsor said, are cutting their monthly garbage collection bill by downsizing to a smaller, less expensive brown bin for items that are not recyclable.
Windsor expects the single-stream effort to increase the city’s recyclables collection by about two-thirds.
Since the city switched to compactor trucks for hauling recyclables, Windsor said he’s reduced those routes from 15 to 11, allowing workers to be reassigned to other jobs.
Waste Management charges the city a $67.20 per ton processing fee.
But the city can still make money because Waste Management has agreed to pay the city 75 percent of the recycled value of each ton – a figure that can fluctuate due to changing prices for recyclables.
This year, recycled material at the West Plains MRF fetches an average of $135 per ton. The city should net roughly $34 per ton as its share, Windsor said.
“I’m also saving about $100 per ton that I don’t have to take anymore to the incinerator. So the real saving is more like $135 per ton,” he said.
The MRF system processes
11 pounds of recyclables per second