The public often believes that landfills and dumps are the same. This is not the case. A dump can be described as an open hole where trash is buried irresponsibly with virtually no monitoring or cover, while a landfill is a carefully constructed and monitored structure which acts as a final disposal option for waste. Landfills are mandated to isolate the waste from the environment and take all actions to keep the environmental effects to a minimum.
Before landfill construction can begin, the best possible site for the landfill must be chosen. Site selection is based on surroundings. Landfills should not be placed on land with a significant groundwater supply, land that houses a plethora of wildlife, or land that contains artifacts of any kind. Once the location is found, a permit from the state authorities is requested. If the permit is approved, design and construction can begin.
Two methods of landfill design exist: trench and area. The trench method was historically used because it is very cheap to implement, but is difficult to use today because of strict regulations and requirements. In this method, a small trench is simply filled with waste. Today, we use the area method which requires liners, landfill gas collection systems, and leachate collection systems. This method is very accommodating to the growing, but necessary, regulations put forth by the EPA.
The basic building block in area landfill construction is the cell. A cell is a small dug out area which is typically filled with one days worth of waste from the community that the landfill serves, however some landfills choose to build large cells and fill them over time. Each cell is lined with material – clay or plastic, depending on the landfill – to keep the environmental impacts of the decomposing waste to a minimum. At the end of the day, the waste is tightly compacted in the cell and covered with soil. A series of these aligning cells make up a lift.
Once these lifts are full, a final cover of soil is placed to cap and seal this inactive portion of the landfill. The cap works to keep water out and contain gas. The final allows for maintenance and monitoring of leachate, gas, and groundwater, but prevents the lift from breaking apart and keeps the waste from dispersing.
Landfills all around the country are working hard to keep our world safe and clean, but landfilling waste should act as a last resort for disposal. So many materials can be recycled and reused, and many of these same materials can take decades to decompose in a landfill. Why not start recycling today?