=======================Electronic Edition========================
RACHEL’S HAZARDOUS WASTE NEWS #109
—December 26, 1988—
News and resources for environmental justice.
——
Environmental Research Foundation
P.O. Box 5036, Annapolis, MD 21403
Fax (410) 263-8944; Internet: erf@igc.apc.org
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THE CATCH-22S OF LANDFILL DESIGN.
The waste hauling industry knows that all landfills will
eventually leak because their own industry trade journals are now
telling the story. WASTE AGE is the main magazine for the waste
industry. The editors of WASTE AGE are not sympathetic to
environmental groups. For example, it was in WASTE AGE’S columns
that you may have read,
“The NIMBY [not in my back yard] syndrome is a public health
problem of the first order. It is a recurring mental illness that
continues to infect the public.
“Organizations that intensify this illness are like the viruses
and bacteria which have, over the centuries, caused epidemics
such as the plague, typhoid fever, and polio.
“….It is time solid waste management professionals stopped
wringing their hands and started a campaign to wipe out this
disease.” (WASTE AGE, Mar., 1988, pg. 197.) Clearly WASTE AGE is
no friend of the grass roots environmental movement. Yet it has
been publishing articles that say what we’ve been saying all
along: the security and safety of landfills is dependent upon the
landfill cap, and the landfill cap is inevitably destroyed by
natural forces.
WASTE AGE has run a series of articles over the past two years
saying why landfills will inevitably leak, and suggesting that
the only solution to the problem is perpetual maintenance of the
closed landfill. Since humans have no experience maintaining
anything in perpetuity, perpetual maintenance is an untested and
unproven, and, one can only say, silly non-solution. If we took
it seriously, perhaps we would develop a large army of landfill
maintainers whose only job in life will be to maintain the toxic
garbage left behind by their parents and their parents’ parents
and their parents’ parents’ parents and so on for generation
after generation.
Despite the silly suggestion that perpetual maintenance of
landfill caps is a way out of our present garbage problem, these
articles contain much good information about why landfills leak.
Remember, a landfill is nothing more than a bathtub in the ground
(perhaps, in the case of a double-lined landfill, one bathtub
inside another). A bathtub will leak if its bottom develops a
hole, or it can simply fill up with water (for example, rainfall)
and leak over its sides. Either way, a landfill can contaminate
the local environment. Therefore, a “cap” is placed over the
landfill when the landfill is full. The “cap” is supposed to
serve as an umbrella to keep rain out, to keep the bathtub from
spilling over its sides.
Writing in WASTE AGE, Dr. David I. Johnson and Dr. Glenn R.
Dudderar of the Michigan State University Department of Fisheries
and Wildlife, have argued,
“There is evidence that the engineered integrity of a cap will
not be maintained over the landfill’s extended life.” (This is
somewhat fancy language for “All landfills will eventually leak.”)
Johnson and Dudderar go on to say, “Regulations may require
bonding for five to 20 years. Yet from a biological and
geophysical point of view this time period is a totally
inadequate maintenance requirement.” (Translation: It may take
nature more than 20 years to destroy a landfill cap, but nature
has all the time in the world, so you’d better be prepared to
maintain a landfill for the long haul–forever.)
Catch 22 #1: A landfill cap is intended to be impermeable–to
keep water out. This means water is supposed to run off the
surface. But this, in turn, invites soil erosion. “But in the
runoff process, cap soil will be carried with the runoff, causing
sheet and rill erosion and, ultimately, gullying of the cap.”
When you get gullies in the cap, it’s all over.
Other physical forces working constantly to destroy a landfill
cap are freezethaw and wet-dry cycles. Soil shrinkage during dry
weather can cause cracks. Rain penetrates the cracks. In winter,
rain freezes to ice and expands, widening the cracks. And so on,
year in, year out, century after century. The cracks not only let
in water, they also provide pathways for plant roots and for
burrowing animals.
Catch 22 #2: To minimize soil erosion, and to minimize changes
due to wet-dry cycles, you need to establish vegetation on the
cap. However, plants maintain their physical stability, and they
gather water and nutrients, through roots, which can penetrate a
landfill cap, destroying the cap’s integrity. Furthermore, plants
provide cover (and food) for burrowing animals, which then burrow
into the cap, destroying it.
A study of a solid radioactive waste landfill reveals that mice,
shrews, and pocket gophers can move 10,688 pounds (5.3 tons) of
soil to the surface per acre per year. “Similar activity would
have a dramatic impact on landfill cap integrity,” Johnson and
Dudderar observe. Burrowing animals of concern include
woodchucks, badgers, muskrats, moles, ground squirchipmunks,
gophers, prairie dogs and badgers. Clay presents little barrier
to such animals; “synthetic liners, measured in mils [of
thickness], are not likely to impede these same mammals,” Johnson
and Dudderar observe. Non-mammals are also a problem: crayfish,
tortoises, mole salamanders, and “a variety of worms, insects and
other invertebrates” can make holes in a landfill cap.
Earthworms alone can have a devastating impact on a landfill cap.
Earthworms pass two to 15 tons of soil through their digestive
tracts per acre per year. “The holes left as they move through
the soil to feed increase water infiltration,” Johnson and
Dudderar comment. They give evidence that worm channels allowed
plant roots to grow to a depth of nine feet in Nebraska clay
soils.
In a section called “The fundamental dilemma,” Johnson and
Dudderar sum up:
“At this point you may well say: ‘If we plant, we’re encouraging
plant and animal penetration of the clay cap. If we don’t plant,
we get erosion or freeze-thaw destruction of the cap.’
“Unfortunately, that is one of the fundamental dilemmas left us
by the normal processes of change in the natural world, be they
the progressive conversion of a grassy field to a forest or the
utilization of cracks in concrete sidewalks by ants and
dandelions.
“This same successional development process, so intensively
studied in the ecological literature, will detrimentally affect
long-term landfill integrity.” So there you have it, right from
the pages of Waste Age: the forces of nature, left to themselves,
will destroy landfill caps, the key element intended to prevent
landfills from leaking.
What hope is there? Perpetual care. A perfectly silly idea. What
reasonable hope is there? None whatsoever. All landfills will
eventually leak. Happy new year.
For further information, see: David I. Johnson, “Caps: The Long
Haul,” WASTE AGE March, 1986, pgs. 83-89; David I. Johnson,
“Capping Future Costs,” WASTE AGE August, 1986, pgs. 77-86; David
I. Johnson and Glenn R. Dudderar, “Can Burrowing Animals Cause
Groundwater Contamination?” WASTE AGE March, 1988, pgs. 108-111;
see also David I. Johnson and Glenn R. Dudderar, “Designing and
Maintaining Landfill Caps for the Long Haul,” JOURNAL OF RESOURCE
MANAGEMENT AND TECHNOLOGY, Vol. 16 (April, 1988), pgs. 34-40. Dr.
Johnson [phone 517/353-1997] and Dr. Dudderar [phone
517/353-1990] are with Department of Fisheries and Wildlife,
Michigan State University, East Lansing, MI 48824.
–Peter Montague, Ph.D.
Descriptor terms: landfilling; caps; capping; failure
mechanisms; failure modes;