In spite of best efforts, the Portland metropolitan region still generates more than one million tons of garbage per year. That garbage has to go somewhere, and it is Metro’s responsibility to manage that garbage in a manner that protects the environment, protects people’s health, and gets good value for the public’s money.

As the Metro Council considers this year where to send the region’s garbage starting in 2020, landfills remain the most readily available, and likely the least expensive, option for getting rid of trash. This article explores the history of how the region has used landfills over the past few decades, how landfills are used today, and what the future may hold.

A brief history of landfills

For many years, garbage was disposed of in more than 50 landfills located throughout the region. Many of those landfills are on places now occupied by homes and retail businesses. Bridgeport Village in Tualatin sits on top of an old landfill. So does the Home Depot store in Oregon City. There’s a former landfill site in Oaks Bottom. In many cases, these former landfills, though used for other purposes, must still be monitored and managed for extraction of landfill methane that generates from buried and decaying waste.

As landfills closed over the years, new options were needed to accept the region’s garbage. In the late 1980s, as the Metro Council was looking for new places to go, Waste Management, Inc., identified a location for a new landfill in Gilliam County, south of the town of Arlington, and about 150 miles east of Portland, on which to build a new landfill.

That landfill, Columbia Ridge Landfill, now takes a majority of our region’s “wet” garbage (the smelly stuff from households and businesses, as opposed to “dry” waste like construction and demolition debris), arriving by truck from various waste transfer stations in our region. Riverbend Landfill, which is also owned by Waste Management and located near McMinnville, also receives a significant percentage of this region’s waste.

Metro’s contract with Waste Management, which requires 90 percent of the region’s wet garbage, destined for a general-purpose landfill, to go to a Waste Management-owned landfill, expires at the end of 2019. Metro could continue to send garbage to landfills and is considering other options for getting the most out of the region’s waste.

Where waste goes, and how it is managed

Landfills are not solely final repositories for buried waste. Garbage deposited at a landfill is covered daily with dirt or other material to reduce odor and the presence of vermin. After garbage is covered, landfills are managed to capture methane from decaying garbage and put that methane to use for heat, fuels or to generate electricity. At Columbia Ridge, the captured methane is used to generate about 12.8 megawatts of electricity, which is sold to Seattle City Light and can power 12,500 homes, according to Waste Management officials.

In 2014 the Portland metropolitan region provided about 480,000 tons of wet waste received at Columbia Ridge Landfill. Most of the other waste coming to Columbia Ridge arrives by rail from Seattle and Kitsap County, Wash.

Landfill owners do not see a landfill merely as a final burial site for waste, but as a facility that supports other technologies for capturing more value from waste.

“Our aspirational goal is zero-waste,” said Jackie Lang, communications manager for Waste Management. “Every ton of waste is a basket of resources. We try to convert those resources into new products.”

Other landfills nearby

Waste Management isn’t the only company with landfills within a four-hour drive of Portland. Waste Connections, Inc., whose local operations are headquartered in Vancouver, Wash., owns and operates the Wasco County Landfill in The Dalles and Finley Buttes Landfill near Boardman. Republic Services, based in Wilsonville, owns and operates Coffin Butte Landfill in Adair Village, north of Corvallis, as well as Roosevelt Regional Landfill in Roosevelt, Wash., across the Columbia River from Arlington.

Finley Buttes, which has 510 acres permitted to receive waste but has used only 90 acres so far, receives most of its waste from Clark County, which arrives via barge sent up the Columbia River. That landfill generates about 4.6 megawatts of electricity from the methane that is extracted, and it also provides heat for a local agricultural business.

Wasco County Landfill is a smaller facility that mostly receives industrial and other clean-up waste from outside the county, along with regular garbage from The Dalles, Hood River and nearby communities.

Dean Large, sales manager with Waste Connections, sees landfills as the most appropriate place to deal with contaminated waste. “I think landfills should be the repositories for lots of contaminated materials currently allowed to remain in place. There’s a high chance of groundwater contamination if you leave it under asphalt in an urban setting [rather] than taking it to a landfill,” which has liners and other barriers to prevent soil and groundwater contamination.

Coffin Butte Landfill receives between 1500 and 2500 tons of waste each day from 14 counties in Oregon, including a small amount of waste from the Portland metropolitan region. It has 184 acres permitted to receive waste and generates 5.6 megawatts of electricity through a gas-to-energy plant. It is also adjacent to a compost facility, Pacific Regional Compost Facility, also owned by Republic Services, that receives mixed food scraps and yard debris from the greater Portland area as well as Marion County.

There are few neighbors to Coffin Butte, which is in a rural area and near the EE Wilson Wildlife Area. Brian May, western regional manager for Republic Services, has seen a lot of changes to the facility over the past decade, with increased recovery of food scraps and greater waste reduction generally. Looking to the future, “I think there’s more potential for increased recovery.”

Roosevelt Regional Landfill receives about 9,000 tons of waste per day, or two and a half million tons per year, nearly all of which arrives by rail from places as far away as Alaska, California and Montana. The landfill generates between 21 and 22 megawatts of electricity from the landfill gas that the waste creates, enough to power between 25,000 to 30,000 homes, according to Don Tibbets, general manager of the landfill.

“The generation is substantial due to the volume of gas brought in,” said Tibbets. “We have higher energy output due to the efficient gas collection,” which he noted captures 98 to 99 percent of the landfill methane generated by the decaying waste.

What the future holds

This year the Metro Council is considering options and choices for where to send the region’s garbage after 2019. With more than 100 years of landfill capacity available to the region, landfills are likely to be at least a part of any approach. There are other technologies that will be considered, and those technologies will be described in further detail in the coming weeks.

What is clear is that the landfills of today are more than simply burial grounds for the stuff people throw away. New efforts and investments are being made to harness more of the energy resource that garbage provides in a landfill. “Landfills that are managed correctly and responsibly are a resource,” said Tibbets.

Large added that he hopes recycling and waste reduction efforts will continue to improve, a sentiment shared by his competitors as well. “Hopefully we won’t use landfills 100 years from now.”