department of public works
Source Reduction and Landfills
All of us make solid waste – commonly known as trash or garbage. The waste we make
is managed for us. What we don’t reuse or recycle is burned (sent to an incinerator)
or disposed of (sent to a landfill).
In the U.S., about 32.5% of solid waste is recycled, 12.5% is burned, and 55% is
buried in landfills. The use of landfills has doubled since the 1960s creating a
huge, smelly problem. Let's get to know the modern-day landfill.
- Landfills are built into or on top of the ground. Trash is isolated from the surrounding
groundwater, air, and rain by a bottom liner and a daily covering of soil or other
suitable material.
- Landfills are designed to bury garbage, not break it down. With little oxygen and
moisture available, garbage decomposes extremely slowly. For example, 40-year-old
newspapers with easily readable print have been excavated from landfills.
- Landfills can, do, and will fill up quickly and be forced to close.
What is a Landfill?
A landfill is a large, outdoor site designed for the disposal of waste. There are
different kinds of landfills that accept different material. There are, for example,
construction and demolition debris landfills that can accept only that material.
Other types of landfills include industrial, hazardous waste and land-clearing debris
landfills. But, generally, the trash and garbage that we throw away every day is
disposed of in a municipal solid waste (MSW) landfill. Landfills are a fact of life.
Although waste reduction, reuse, recycling and composting divert large amounts of
MSW from disposal, some waste still must be disposed of in landfills.
Landfills are not just holes in the ground.
In the past, there were few or no regulations regarding landfills. It showed. Many
people remember smelly, unlined dumps that contaminated groundwater and caused other
environmental problems. It’s different today. Modern landfills are well-engineered
facilities that must meet strict U.S. Environmental Protection Agency (EPA) and
S.C. Department of Health and Environmental Control (DHEC) regulations that were
established to protect human health and the environment. All landfills must be approved
(receive a permit) from DHEC. When you think of it this way – and most of us don’t
– garbage disposal is no less an essential public service than police or fire protection.
MSW landfills must be built in suitable geological areas away from faults, wetlands,
flood plains and other restricted areas. The design of landfills includes plastic
liners and other materials like clay to prevent groundwater contamination. Monitoring
is required to test groundwater quality and determine if there is any contamination.
Daily operation of landfills includes compacting (crushing) and covering waste with
several inches of soil or other cover material to reduce odor, litter and control
rodents and pests. Closed landfills must have a final cover that includes a synthetic
cap and a soil layer. Once the landfill is closed, the responsibility of the landfill
operator doesn’t end. Landfill operators must set aside funding to provide environmental
protection during and after the closing of a landfill. In short, today’s landfills
are expensive to design, build and maintain. Beyond the expense, landfills also
are difficult to build simply because the public frequently opposes new construction.
People remember the poor practices of the past and are concerned about their health
and environment as well as property values, noise, odor and traffic if a landfill
is built near their community. But the modern landfill was designed to lessen or
overcome these problems, particularly open dumps and garbage incinerators that polluted
the air.
What's Going On Today?
Nationwide, the number of active MSW landfills has shrunk from nearly 8,000 in 1988
to 1,754 in 2007 according to the EPA. There are thousands of closed landfills.
In South Carolina, there were 18 permitted MSW landfills operating in fiscal year
2008 (July 1, 2007 to June 30, 2008). But what landfills lack in numbers is made
up in size. Landfills are much bigger today than they were in the past. As such,
today’s landfills have a much longer lifespan and frequently accept waste from a
much larger geographical area.
The Myth of Biodegradation
Most of us assume that when we throw something away, it will eventually break down
or decompose in the landfill. You know, a return to nature kind of thing. Well,
not necessarily. It depends on what was thrown away – and a lot of other things.
One of the most recognized research efforts on decomposition – also called biodegradation
– has been the work done as part of the Garbage Project at the University of Arizona.
Researchers mined local landfills to learn about modern civilization. Among their
findings – garbage does not break down in landfills. The Garbage Project discovered
that landfills are a much more static structure and that biodegradation takes a
lot longer than previously thought. Air and water are necessary for biodegradation.
Under normal landfill conditions – that is when the garbage is covered by dirt and
the landfill is relatively dry – the only garbage that truly decomposes are certain
types of food scraps and yard trimmings (banned from MSW landfills in South Carolina)
and even that takes a long time. Hot dogs and pastries, buried as long as 15 years
ago, were still recognizable.
Grass clippings were still green. Newspapers, long thought to be easily biodegradable,
were found in landfills virtually intact after being buried for decades. The bottom
line is this: throwing something away is a lifetime decision in more ways than one.