Answering the call

Portland, Oregon, considers itself to have a progressive approach to waste diversion. So when the regional government that serves Portland and 27 other jurisdictions in the area passed a recycling ordinance requiring all dry discarded material to be processed for recovery, Waste Management (WM) responded in kind.

The Houston-based firm, with a major presence in the region, designed what it calls an environmentally friendly facility with some of the most sophisticated technologies available to sort materials for recycling. Eight years later, the Tualatin Valley Waste Recovery (TVWR) continues to refine its processes, contributing substantially to the region’s recycling rate.

Matt Stern, Pacific Northwest-British Columbia area recycling director for WM, says the facility was built to support the regional governing authority, Metro, which had passed the Enhanced Dry Waste Recovery Plan (EDWRP). “They wanted to jump-start additional recycling, so this is what they came up with,” says Stern. “Our facility was built to support that ordinance.”

The ordinance targets wood, metal and cardboard. The WM facility recovers all those materials, along with mixed paper, inerts (dirt, rocks, rubble and concrete) and asphalt shingles.

“They wanted all dry material, whether it was wood, metal, cardboard, paper or construction debris, to be sorted before it got landfilled,” says Stern of Metro’s ordinance. “Their thought was if they jump-start that activity, they would boost their recovery, and they were right.”

Dry waste includes several different categories: discarded materials generated at strip malls from businesses that do not produce food waste, materials placed in roll-off boxes and demolition debris. The waste is characterized as not putrescible, meaning it does not spoil. Commercial businesses and construction, roofing and demolition contractors make up the majority of WM’s customer base for the plant.

EMBRACING MECHANICS

Materials processed for recycling at the WM site go through a mixture of mechanical and manual sorting that Stern says “allows us to target those recoverable items.”

When loads arrive, a floor sort is done to pull out bulky items, such as washers and dryers and large pieces of wood and metal. The remaining materials are loaded onto an infeed conveyor to a finger screen, which separates material larger than 8 inches from material smaller than 8 inches.

Sorters pull out targeted items from the material larger than 8 inches, while the smaller materials are mechanically sorted using a magnet and a fines screen to remove the material smaller than 2 inches from the belt. Then the material travels through a manual sorting area to pull out targeted material from that 2-to-8-inches fraction remaining.

The material between 2 and 8 inches goes through a General Kinematics air knife, which separates the light material from the heavy material. Light material includes items such as paper and plastic bags, while heavy material consists mainly of brick, tile and concrete. The middle fraction is typically wood, and that goes through an Eagle Vizion, Sherbrooke, Quebec, optical sorter. It identifies the wood and shoots it off the belt with an air valve mechanically. The entire system was designed by Sherbrooke OEM, Sherbrooke, Quebec.

“On the spectrum of C&D sorting equipment, this system is toward the higher end of sophistication,” says Stern. He says C&D material typically is manually sorted for the easier-to-sort, bigger target materials, such as wood and metal.

“We’ve taken it a little further with these more mechanical [pieces of equipment],” Stern says. He adds, “We are still looking at other ways to add more mechanical sorting to the system but have not designed anything yet that we are ready to install.”

The facility receives 10,000 tons of material per month that is processed through the system. Another 10,000 tons of material received at the facility are clean loads of metal or wood that require no further processing.

Tanya Stewart, area sales director for WM Pacific Northwest and British Columbia, says customers have embraced the facility and its ability to separate materials. “Recycling is easier for C&D projects because there is no longer a need for separate containers at the job site,” she says.

DEFINING FEATURES

Beyond the mechanical sorting equipment, another defining feature of WM’s recovery facility is its location. It sits on the same property as a landfill. Hillsboro Landfill, also owned and managed by WM, accepts dry materials that cannot be recycled at the recycling center, such as contaminated soil.

When customers arrive at the 390-acre property, they drop off loads to the facility that accepts the material being hauled—either to the landfill or to the recycling facility.

Because many of the materials that arrive to the site are required to be recycled, the co-located recycling operation has extended the life of the landfill. The landfill also uses aggregate as road base from the recycling facility.

The facility’s design elements also are earning distinction. TVWR achieved Leadership in Energy and Environmental Design (LEED) Gold certification for its construction and design. Helping the facility earn the certification were its many energy-saving features, which rival the equipment on the site for sophistication, according to WM.

For example, a translucent roof allows for natural lighting. Rainwater is harvested into a 140,000-gallon tank and reused for cleaning, dust control and fire suppression. Walls are designed to allow fresh air to circulate through the facility at all times to protect air quality.

Stern says what makes the facility and what it does special goes even deeper. “The project is really unique not only because of the waste stream that we are targeting, the equipment we are using and the building we are in, but [also] the incentive to target this portion of the waste stream has been very successful,” he comments.

A SOLID PARTNER

Stern applauds Metro for developing the ordinance and for its forward-thinking commitment to reducing waste.

“They [Metro] had the idea. I am not sure they really knew how successful it would be and how perfect of a public-private partnership it would be,” Stern says. “They didn’t know what kind of investment was going to happen.”

“I am not sure [Metro] really knew how successful it would be and how perfect of a public-private partnership it would be.” – Matt Stern, WM Pacific Northwest- British Columbia area recycling director

He adds, “It worked because companies like Waste Management invested in that infrastructure.”

Stern recalls during construction of the facility in 2008, the crashing economy raised major concerns over whether investing millions of dollars would pay off.

“Now looking at it with the benefit of hindsight,” he says, “it is clear that this structure—where you have a supportive regulatory entity providing an incentive for infrastructure development [coupled with] construction and growth from the private sector—that model, I think, can work.”

The author is editor of Waste Today and can be reached at ksmith@gie.net. A version of this article first appeared in the July/August issue of Construction & Demolition Recycling, a sister publication.