On Tuesday, May 17th, Waste Loop employees toured the Waste Management Greater Wenatchee Landfill. Arriving at the Greater Wenatchee Regional Landfill felt very ominous; recordings of crows and ravens played from speakers to prevent scavenging birds from digging to find trash. The wind was blowing, and it was a bright, cold spring day. Our tour was given by Eric, who is the site manager. We walked down a dirt road that circumnavigated the open cell: the active area where trash is exposed and being deposited. From where we were standing, we looked down into a large pit with different trucks and machines driving around. A large vehicle with giant studded wheels and a rake attached to the front, an 836 Compactor according to Eric, drove over the freshly deposited trash and compressed the garbage to achieve maximum density without wasting fuel. The optimal number of passes for the compactor to drive over 2 ft of trash is three times, as this compacts the waste the most without unnecessarily burning fuel. The Greater Wenatchee Landfill has an area of 135 acres that will be filled with garbage. Each cell is 100 feet deep, and the volume capacity of the site is 37 million cubic yards, of which 7 million cubic yards are currently full. The average daily input of trash to this site is 1,000 tons, coming from Chelan, Douglas, and Kittitas Counties. If this rate continues, the landfill will be full and closed in 89 years.
This site has been used for garbage disposal since 1968 when it was operated by Eastmont Disposal and waste was burned. In 1986, Waste Management purchased the site and updated the infrastructure to be a landfill. One of the biggest concerns with a landfill is gas release, specifically methane. Methane is one of the most potent greenhouse gasses with 25 times the heat-holding capacity in the atmosphere compared to carbon dioxide (CO₂). At this site, the cells are lined to prevent gasses from entering the soil, and the cells are under vacuum pressure so methane and other harmful gasses are congregated. After being collected, the gas is burned off at a single torch smoke stack on site. This transforms methane and VOCs (Volatile Organic Compounds, which are chemicals emitted as gasses) into CO₂ gas, which is then released into the atmosphere. To ensure that methane is not leaking out from the landfill, a monitor walks the entire area with a “super sniffer” that detects methane concentrations outside of the allowable range of 500 ppm (parts per million). In the coming years, Waste Management hopes to transform the methane being released by the landfill into compressed natural gas, which would then be used to power all of the WM trucks hauling waste. There is already a program in place for this process in Seattle, but the infrastructure is not yet present at the Wenatchee landfill.
Another big concern with the landfill is the leaching of liquids into the soil and groundwater. Garbage is about 36% liquid, so through compaction, a lot of potentially harmful fluids are expelled. This is mitigated by lining the cells with several layers that collect liquid waste. 3500 pounds of leachate are collected each day, which are sent to a lined leachate pond for evaporation of the water. Harmful contaminants are left behind when the liquid evaporates, and when the landfill is closed, this liner will be disposed of in another landfill. Water quality is tested flowing in and out of the landfill area, and any changes in quality are of huge concern, resulting in immediate action to control the contamination.
When speaking with Eric, we asked about the most prevalent issues he faces while managing the operation of this landfill. One of the first things he mentioned was the spread of garbage from birds and wind. This issue is mitigated by covering the exposed garbage at the end of each day with a tarp or with dirt, and by playing the audio recordings of aggressive birds meant to deter them from digging into the landfill and spreading waste. He also talked about dust and erosion problems. In the active cell, the dirt is exposed to the wind and sun, drying it out and spreading it in the air as dust. To mitigate this, large trucks drive around the open pit spraying down water. Once the cell is closed, the dirt removed to open the pit for trash is reapplied to cover it up. When the cell is dug, the soil profile is inverted, so the deepest soils are at the top of the pile to cover the cell back up. This soil is typically sterile, making it very difficult for plants to establish in these areas. This lack of vegetation also contributes to erosion and dust issues. To help promote a healthy shrub-steppe ecosystem on the property, native plant species are used to revegetate areas. Another way that native plants are supported is through the biocontrol of invasive species; the Knapweed Weevil has been introduced to control invasive knapweed, and American Kestrels are provided boxes to promote their nesting, helping to reduce the population of invasive starlings. These efforts, along with the increased availability of water for wildlife through “guzzlers”, have given the landfill the designation of being certified by the Wildlife Habitat Council.
Once the landfill is closed, it must continue to be monitored for adverse environmental impacts, especially concerning water quality and gas release. When asked about diverting waste from the landfill, one of Waste Loop’s goals, Eric was all for it. He recognized that a landfill is a temporary solution to our mounting waste. He also said that they could transition to a MRF (material recovery facility; essentially a recycling center) if the waste stream transitioned that way. However, right now, there is still the need for a landfill, and Eric is proud to manage this one. Landfills are no longer as present in smaller communities, which he says is a good thing. There are many issues with smaller municipalities managing their own landfills, and a lot of mismanagement of these spaces resulting in higher methane release, groundwater contamination, and more erosion. Waste Management tries to hold their landfills to high standards, making a necessary evil less problematic.