The main Hanford landfill for contaminated material from the nuclear site’s environmental cleanup has reached a new milestone, 17 million tons of waste disposed of since it opened in 1996.
The Environmental Restoration Disposal Facility in central Hanford accepts waste with hazardous chemical and low level radioactive contamination.
“Reaching 17 million tons of material disposed at ERDF shows the excellent cleanup work being done at the Hanford Site,” said Mark French, the Department of Energy project director.
It is the largest disposal facility in the DOE cleanup complex. Its 70-foot-deep disposal area covers roughly the same area as 52 football fields, although some areas are already full.
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The central Hanford landfill has been called the heart, backbone and hub of Hanford cleanup, according to the Environmental Protection Agency, a Hanford regulator.
It prevents Hanford waste from contaminating the groundwater, which moves toward the Columbia River, said Jeff Armatrout, director of waste operations for Washington Closure Hanford, which operates the landfill for DOE.
Most of the waste in the landfill now comes from cleanup of the 220 square miles along the Columbia River, where the groundwater may be just 30 feet below the surface. At the central Hanford landfill, more than 200 feet of soil and rock sits above the groundwater.
Much of the threat to the groundwater comes as precipitation or other water carries contamination deeper into the ground.
At ERDF, a lining system below the landfill collects any water that has filtered through the landfill, picking up contamination. The water can come from precipitation or the water sprayed in the landfill to keep down dust and prevent the airborne spread of contamination as waste is placed.
Now filled sections are temporarily covered with a heavy duty plastic cover and about a foot of soil. On top of it grows native grasses that soak up some of the precipitation and keep the wind from blowing away the soil.
Decades from now when more Hanford cleanup is completed, the landfill will be permanently capped.
“It’s an engineered landfill to prevent anything getting out for thousands of years,” Armatrout said. Much of the radioactivity in the contamination will have decayed by then.
About 85 percent of the waste in the landfill now is contaminated soil, much of it dug up near Hanford’s nine reactors that together produced plutonium for the nation’s nuclear weapons program from World War II through the Cold War. Contaminated cooling water used in the reactors was often dumped into the ground.
The landfill also holds debris from demolished buildings and from burial grounds. During Hanford’s early days holes were dug and contaminated waste buried, sometimes not far above groundwater. In addition to radioactive contamination, the waste may include hazardous chemicals, such as mercury, asbestos, beryllium, chromium or lead that may need to be treated at ERDF before disposal.
The landfill is designed to be expanded as needed and has capacity now for about 1.6 million tons of additional waste. It is designed in cells, or disposal areas, that were initially in pairs 500 feet wide and 1,000 feet long. More recent “supercells” are the size of two earlier cells.
Hanford officials anticipate that the next addition to the landfill could be designed in about 2018, with the landfill expanded the next year.
Now cells seven and eight are topping out, supercell nine is full except for the top 30 feet and supercell 10 has space available to about 45 feet deep.
Waste disposal is expected to slow by midsummer when much of the cleanup along the Columbia River is completed by Washington Closure. By July about 80 containers a day could be brought to the landfill, down from a peak of 854 containers a day in spring 2011 when the Hanford budget was boosted by economic stimulus money. Containers hold about 20 tons of waste.
Next year disposal might ramp up again as cleanup shifts from near the river to central Hanford.
Washington Closure’s contract expires at the end of September, with no word yet on whether it will be renewed to finish up some of the remaining cleanup along the Columbia River.
CH2M Hill Plateau Remediation Co. is expected to be the main user of the landfill in the future as the focus of cleanup is planned to shift from the area along the river to its work to clean up central Hanford. Its contract includes a provision allowing operation of ERDF to be passed to it after Washington Closure’s work at Hanford has been completed.
Now ERDF employs up to 150 workers and requires 70 trucks to haul waste from across Hanford to the landfill.
Keeping radiation and other contamination under control is not a problem, Armatrout said. It’s the traffic at the landfill that is a challenge, requiring some careful choreography at busy times.
“(The) concern is keeping the people safe from heavy vehicles,” he said.
In addition to 75 vehicles, there may be 30 “yellows” — bulldozers, graders, dump trucks and other heavy equipment — at the landfill.
“The team at ERDF can be proud of their amazing safety record,” he said.
The waste transport drivers have driven 25.5 million miles with just two accidents serious enough to record with the Department of Transportation since ERDF opened. That’s equivalent to about 100 trips to the moon, he said.