The Lowdown on Landfills

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You’ve just swallowed your last sip of Dr. Pepper as you crumple the wax paper from your cheeseburger. You gather the  paper napkins, plastic straw and a few burnt fries among other things. After you toss this waste and leave your tray, more than likely, you never think about this trash again.

We’ve all heard about the local landfill on the outskirts of town, but most of us are unaware of its inner-workings and effects on the surrounding areas. Americans generate an average of 4.6 pounds of trash daily per person. So, where does it go?

Let’s get to the bottom of what really goes on behind a landfill’s gates.

The Purpose of a Landfill

Of the estimated 251 million tons of consumer solid waste generated each year in the U.S., approximately 32.5 percent of the trash is recycled or composted, 12.5 percent is burned and the remaining 55 percent is buried in landfills.

Currently, there are 3,091 active landfills and more than 10,000 old municipal landfills in the United States. Photo: Kid-at-art.com

According to the EPA, as of 2007, there are 1,754 active landfills in the U.S. Photo: Kid-at-art.com

According to the EPA, municipal solid waste landfills (MSWLFs) are “publicly or privately owned, new, existing, or lateral expansions of landfills that receive household waste (including hazardous household waste), and that may also receive other types of RCRA Subtitle D wastes, such as commercial solid waste, non-hazardous sludge, and industrial solid waste (including exempt hazardous waste from CESQGs).”

The landfill is a structure built on top of the ground, or in a shallow pit,  in which trash is confined and secluded from groundwater, air and rain.

The bottom of the landfill is lined while the top is repeatedly covered with soil. A landfill uses clay liners to isolate trash, while a municipal solid waste (MSW) landfill can use synthetic or clay liners.

The purpose of a landfill is to isolate waste from its surrounding environment, preventing water contamination and contact with air. However, landfills are not built to decompose trash.

How a Landfill is Built

There are strict regulations on where a landfill can be built and how it can operate. The process always starts with a proposal. If approved, an environmental study must be done on the prospective spot in order to determine various environmental factors:

  • The necessity of the area of land for the landfill
  • The composition of the underlying soil and bedrock
  • The flow of surface water over the site
  • The impact of the proposed landfill on the local environment and wildlife
  • The historical or archaeological value of the proposed site

Footing the Bill

In most cases, building landfills is the responsibility of the local government. Once the environmental impact study is completed, permits must be obtained from the local, state and federal governments. The cost of building a landfill varies according to location, application fees and engineering cost.

For example, a MSW landfill in Kentucky will run approximately $500,000 to $1 million for the application and design engineer cost, but this fee doesn’t include the construction of the landfill liner. That will cost $75,000 per acre. Generally, the money is raised from taxes or municipal bonds. So, it’s possible that funding for the landfill could come from taxpayers’ pockets. But the upside to using public funding is local approval is required in order to continue with the construction of the landfill.

How a Landfill is Operated

Landfills must be open and available every day. While the majority of its customers are municipalities, commercial and construction companies, residents are also permitted to use the landfill in most cases.

The bottom of a landfill is lined with high density polyethylene (HDPE) plastic to protect the surrounding environment. Photo: eia.doe.gov

The bottom of a typical landfill is lined with high density polyethylene (HDPE) plastic to protect the surrounding environment. Photo: eia.doe.gov

A typical landfill is divided into 17 sections (or stations), each having a specific purpose. The landfill’s entrance has a recycling center with dedicated containers for specified materials. Generally, the recycling area is open to residents and is free to use.

Customers with larger trash loads are sometimes charged to dispose their trash. These are generally construction, demolition or commercial companies.

These customers must have their trash weighed and are required to pay a tipping fee based on the weight of their waste. Tipping fees can range from $10 to $80 per ton.

Tipping fees are a large part of the overall operating budget of a landfill. Household hazardous waste (paints, pesticides and other chemicals) is banned from the landfill, but there may be a drop-off station for these items.

Some paints can be recycled, and some organic chemicals can be burned. The remainder of the landfill is lined with supply structures. These usually consist of soil for the landfill, a runoff collection pond, leachate collection ponds and a methane station.

Impact on the Environment

Landfills present potential threats to both the environment and human health. Although landfills are lined to protect the surrounding environment, malfunctions can still occur. According to U.S. Geological Survey, because chemicals and gasses pass through the liner and its plastic tubes, they become brittle, swell and breakdown. As a result, not only is leakage possible, it’s almost inevitable.

The bioreactor landfill is a developing advancement that will help preserve the surrounding environment. Photo: EPA.gov

The bioreactor landfill is a developing advancement that will help preserve the surrounding environment. Photo: EPA.gov

Those working or living around a landfill with leakage face threats such as an increased risk of cancer and birth defects due to hazardous airborne releases from chemicals in both active and inactive landfills, according to a report by G. Fred Lee & Associates, an environmental consulting firm.

Leakage isn’t the only problem landfills encounter. Because they are lined with high density polyethylene (HDPE) plastic, waste decomposes at a much slower rate.

The decomposition process for waste in landfills extends for decades. This results in the evaporation of available space.

Advancements for the Future

Thankfully, it’s not all bad news. The waste management industry is working to correct these problems with the development of bioreactor landfills. These landfills use liquid and air to enhance microbial process, accelerating the decomposition process.

Bioreactor landfills may be more beneficial to the environment in comparison to today’s traditional landfills. They will provide a decrease in long-term environmental risks as well as alleviate landfill operating and post-closure costs. Bioreactor landfills could extend the lifespan of an average landfill by as much as 20 years.

Currently, Waste Management is researching both bioreactor landfills and how to extend the life of current landfills. According to its Web site, Waste Management is including expansions that are probable at 62 landfills. The estimated average remaining life of Waste Management’s current landfills is 35 years.

“Waste Management continues to lead the industry in solutions that impact the future of solid waste management, such as Next Generation Technology,” the Web site states. “This alternative approach accelerates the decomposition of waste in landfills so that it occurs within years rather than decades.”

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