Disposing of garbage is not as simple as digging a hole and filling it with refuse. There are strict state and federal regulations that need to be followed.
Virginia Department of Environmental Quality (VDEQ), Prince William County, the Environmental Protection Agency (EPA) and the U.S. Army Corps of Engineers all have regulations pertaining to air quality, water quality and solid waste handling which the County must follow.
“You can’t just open a landfill because you feel like it. It’s highly regulated,” said Fouad Arbid President, Solid Waste Services, LLC, the third-party engineering company overseeing construction of a new section of the landfill called a cell. “There are federal regulations and State regulations that say when you open municipal solid waste landfills, you have to line them with certain minimum liner requirements. We have to control all of the environmental aspects of it.”
The Prince William County Landfill Complex recently completed construction on a new twelve-acre cell to collect garbage for the next three to four years as part of its ongoing operation.
The cells, constructed in 10 to 12 acres, consist of a 12-inch layer of soil at the bottom of the cell, a layer of geosynthetic clay liner which expands to 10 times its volume when liquid hits it. By expanding the clay will fill any small holes that might occur in the final polyethylene liner that covers the soil and the clay liner. The cell system is constructed to block leachate, the liquid that comes from decomposing garbage from going into the ground water and to catch it.
Polyethylene liners have been in use at landfills everywhere for more than 30 years and are reliable. “There have been no complaints that any liners have leaked, when installed properly,” said Sadhu Sandhu Principal Engineer at the landfill.
Gravity forces the leachate, with its contaminants and toxins, into the drainage system that feeds into a 1-acre lagoon at the landfill. The leachate is then pumped from the lagoon to a waste water treatment plant every night.
As the cells fill up, they must be covered nightly with six inches of dirt, or other coverings approved by DEQ, such as tarps, and shredded tires to keep rainwater from getting into the system.
Decaying garbage also produces methane, which is captured by another polyethylene cap placed on top of the garbage as the cell fills up. An 18-inch layer of soil on top of the liner completes the cell. A second system of pipes and underground infrastructure collects the methane and sends it to engines at the landfill that burn it to produce electricity. The electricity produced by the engines is enough to power roughly 7,000 homes.
The closed system keeps the environment safe from all contaminants. “Nothing can escape up. Nothing goes down,” said Sadhu Sandhu Principal Engineer.