Answering the call

Portland, Oregon, is known for its progressive approach to waste diversion. So when the regional government that serves Portland and 27 other cities and counties 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 strong presence in the region, pulled out all the stops with an environmentally friendly facility design and some of the most sophisticated technologies available to sort out materials for recycling. And eight years later, the facility, Tualatin Valley Waste Recovery (TVWR), continues to refine its processes, contributing substantially to the region’s recycling rate.

Matt Stern, area recycling director, WM, Pacific Northwest-British Columbia, says the facility was built to support the regional governing authority, Metro, passing the Enhanced Dry Waste Recovery Plan (EDWRP). “They wanted to jumpstart 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 Waste Management 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 jumpstart that activity, they would boost their recovery, and they were right.”

Dry waste includes everything from 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.

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 out 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 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 brick, tile and concrete. The middle fraction is typically wood, and that goes through an Eagle Vizion 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 towards the higher end of sophistication,” says Stern. He adds C&D material is typically manually sorted for the easier-to-sort, bigger target materials like wood and metal.

“We’ve taken it a little further with these more mechanical [pieces of equipment],” says Stern, adding, “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 and require no further processing.

Tanya Stewart, area sales director WM-Pacific Northwest and British Columbia, says customers have embraced the facility and its ability to separate materials for them. “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 a customer arrives at the 390-acre property, he or she drops off loads to the facility that accepts the material being hauled—either to the landfill or to the recycling facility.

Because much 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 are also distinguishing. 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.

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 and walls are designed to allow fresh air to circulate through the facility at all times to protect air quality.

But Stern says what makes the facility and what it does so 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 the incentive to target this portion of the waste stream has been very successful,” says Stern.

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,” recalls Stern. “They didn’t know what kind of investment was going to happen.”

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

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

“I don’t know that we could have seen what the future held at the time. Now looking at it with the benefit of hindsight, 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 Construction & Demolition Recycling and can be reached at ksmith@gie.net.