One point twenty-seven million tons. That’s how much garbage was added to Orchard Ridge last year alone. The landfill is located in the Village of Menomonee Falls. Of the 85 licensed operations in Wisconsin, Orchard Ridge is the largest.
On an average day 400 to 600 trucks haul in garbage from four counties – Ozaukee, Washington, Waukesha and Milwaukee.
But, how much more waste can the 23-year-old landfill hold? And what will become of the site once it is full?
Those are questions that listener Helen submitted to WUWM’s Beats Me. She’s been watching the landfill grow while commuting from Cedarburg to Milwaukee and wonders about the site’s future.
WUWM’s Susan Bence ventured up the side of the ridge with landfill manager Steve Meyer to answer Helen’s questions. "Right now we’re sitting on about 110 feet of trash, roughly, from top to bottom,” he explains.
That’s a tad taller than a 10 story building.
Meyer says Orchard Ridge is highly engineered. During its construction, crews followed prescribed excavation plans and lined the pit with at least four feet of DNR-approved material.
There’s no denying risks exist. The decomposing waste produces methane, a flammable gas that can explode.
But, Meyer says Waste Management, the company that owns the landfill, monitors the methane and captures it to create power. “We have a gas-to-energy plant on site and we’re producing enough power that goes out on the open grid for about 15,000 homes 24/7.”
In comparison, by the end of 2017, Wisconsin will reach 85 megawatts of solar energy capacity, which enough to power 11,500 households.
Meyer says the Orchard Ridge landfill will continue to produce methane decades after its active landfill days end, so the monitoring will also continue.
He says Waste Management keeps a watchful eye to prevent decomposing fill from leaching into the groundwater. During the landfill’s construction, Mayer says, work crews installed monitoring wells strategically throughout the landfill. “They figure out which way the aquifer flows and that’s where they place these wells… Twice a year they get monitored and all of that water gets sent to a lab.”
Groundwater monitoring will also have to continue for decades after the landfill is capped.
As for biosoil, or soil that’s been contaminated with gas or diesel fuel, Meyer considers it a resource. "We clean that material up, add some fertilizer to it and just let it sit. I usually like to build 20,000 ton piles and then after about 6 months, we’ll get it tested,” he explains. “If it comes back clean, we can use it for beneficial reuse like berms."
Meyer estimates that he can squeeze a couple more years’ worth of waste onto the landfill before it's capped.
Waste Management says its goal for when Orchard Ridge retires in a couple years is to create a park-like look at the landfill.
But that doesn't mean you'll see a canopy of trees popping up on the slope. “You can’t sink a pole in there or put any structure on there would require a footing that penetrated the cap,” public affairs manager Lynn Morgan explains. “You wouldn’t plant trees here either because the roots would penetrate the clay cap.”
However, the closure of Orchard Ridge won't mean the end of operations there.
Waste Management owns a total of 724 acres at the Menomonee Falls site and plans to tap into 45 acres of it after Orchard Ridge reaches capacity to create a new landfill. There are already three retired landfills on the property, two of which are superfund sites - Omega Hills North and Lauer I.
The DNR is looking over the company’s feasibility study to construct a new landfill, and is expected to release the plan for public comment any day.
Waukesha County Environmental Action League is keeping an eye on the plan. The local environmental group worries about increased stress more landfill could place on the region’s air, land and water.
As for question asker Helen, she’s happy to know more about the landfill that she has wondered about for a long time.
Have an environmental question you'd like WUWM's Susan Bence to investigate? Submit below.