 Where
there are animals, there is animal waste, and as the growth of
industrial farming concentrates thousands of animals on
increasingly fewer farms, it produces massive amounts of animal
waste on relatively small plots of land. When too much waste is
produced in one place, there’s no safe, cost-effective way
to either use it productively or dispose of it. While government
regulation and better waste management practices can make a
difference and should be encouraged for existing farms, the
problem of livestock waste will never end so long as we rely on
concentrated industrial farms to produce our food.
Mountains of Manure
The USDA estimates that more than 335 million tons of “dry
matter” wastes are produced annually on farms in the
United States, representing almost a third of the total
municipal and industrial waste produced every year.i
What’s more, animal feeding operations annually produce
about 100 times more manure than the amount of human sewage
sludge processed in US municipal wastewater plants.ii
One dairy farm with 2,500 cows produces as much waste as a city
with around 411,000 residents.iii Unlike human waste,
however, in most cases the law does not require that livestock
waste is treated.
At farms where animals are allowed to graze on pasture,
much - if not all - of their manure is excreted directly onto
the land, serving as a fertilizer and recycling nutrients back
into the soil. On industrial livestock farms, however, animals
drop their manure in the houses where they live. From there, the
manure must be cleaned out, transported, and stored, each step
of which can negatively affect the environment. Simply
cleaning out livestock houses can waste vast amounts of
water—a dairy operation that utilizes an automatic
“flushing” system can use up to 150 gallons of water
per cow per day.vi
Manure is usually stored for many months, often in giant
outdoor pits known as “lagoons.”vii As it
decomposes, the manure emits harmful gases such as ammonia and
hydrogen sulfide.viii Meanwhile, these lagoons often
leak or rupture, polluting the surrounding soil
and water systems. One study conducted by North Carolina State
University in 1995 estimated that as many as 55% of the manure
lagoons on hog farms in that state were leaking enough to cause
environmental damage.ix Even without leaks, manure
lagoons are so fragile that major storms often result in
overflows. Perhaps most famously, in 1999, the majority of North
Carolina’s manure lagoons spilled over into waterways
during Hurricane Floyd,, leading to widespread water
contamination. What made matters even worse was that North
Carolina, like most states, requires no treatment of animal
waste.x
Since manure is produced on factory farms in excess of
what can safely be absorbed by the farm’s soil, it is often shipped to
neighboring farms for use as fertilizer. Unfortunately, manure
is quite heavy, so transporting it both consumes large amounts
of fuel (needed to power the trucks that
haul it) while at the same time contributing to air pollution.xi
Once the manure arrives at its destination, it is sprayed
onto farm fields as fertilizer. Under the current system of
animal production, however, there is always more manure
available than can possibly be absorbed by the soil as
fertilizer. In fact, studies show that between 1982 and 1997, as
industrial agriculture grew, the US experienced a 64 percent
increase in the amount of manure that could not be absorbed by
our soils.xii This practice is not only harmful to
the soil, but can also result in contamination of human drinking
water and lead to serious public health problems.
Animal Waste, the
Environment, and Human Health
People often believe that animal manure is harmless, but in
truth it can be quite hazardous. Factory livestock facilities
pollute the air and release over 400 separate gasses, mostly due
to the large amounts of manure they produce.xiii The
principal gases released are hydrogen sulfide, methane, ammonia,
and carbon dioxide.xivgasses can be dangerous air pollutants that threaten both
the environment and human health. Nitric
oxides are also released in large quantities from farms through
manure application,xv and are among the leading
causes of acid rain.xvi
The risks of lagoon leakage, overflows, and illegal
discharge of waste also pose a direct threat to the quality of soil and water
systems. A report for the U.S. Geological Survey documented over
one thousand spills and dumps of animal waste in the ten
Midwestern states it surveyed over the course of three years.xvii
Manure from leaky lagoons or saturated farm fields has also been
known to enter public water sources and infect humans.xviii
For example, a study of waterborne disease outbreaks from 1986
to 1998 conducted by the Centers for Disease Control
demonstrated that in every case where the pathogen could be
identified, it most likely originated in livestock.xix
Among the many minerals usually present in high
concentrations in animal waste are phosphorous and nitrogen,
which can cause a range of ecological problems like fish kills
or a loss in biodiversity.xx
The ammonia present in manure waste can be converted to nitrates
in water systems,which in turn can cause sickness and even death
in humans.xxi These include dangerously low
blood-oxygen levels in babies (known as “blue-baby
syndrome”), spontaneous abortions, and possibly cancer.xxii
The storage of animal waste under industrial livestock
facilities and in manure tanks also poses a direct health risk
to both animals and humans. Since animal waste is often stored
directly beneath the barns in which the livestock live,
livestock commonly die from poor ventilation that allows for the
buildup of toxic gases inside confinement facilities.xxv
What’s more, manure pits have been known to claim the
lives of farm workers, and between 1992
and 1997 at least twelve workers died due to asphyxiation by
manure gases and drowning while trapped in manure lagoons.xxvi
The gases in livestock facilities can also pose other risks to
workers; for example, methane is highly flammable, and if not
vented properly from manure tanks it can cause explosions.xxvii
Regulation and Technology
in Managing Waste
Until recently, there has been very little regulation of animal
waste. Federal law changed in 2002 to require large livestock
facilities to apply for National Pollutant Discharge Elimination
System permits for their waste discharge. Although this still
leaves it up to the individual states to define and enforce
pollution guidelines, it is a step towards tighter regulation of
agricultural waste.xviii The Environmental Protection
Agency also has the right to prosecute those who discharge
animal waste illegally under the Clean Water Act, xxix
although these cases are brought infrequently and regulation of
animal waste in the US still lags far behind much of the rest of
the world. For instance, Denmark, Japan, the Netherlands, Sweden
and the United Kingdom all have programs to ensure that no more
animal waste is applied to soil than can be absorbed as
fertilizer.xxx
Apart from regulation, there are some other innovations
that may help control the potential problems associated with
animal waste. Researchers have discovered that adding sodium
carbonate—a mineral commonly found in laundry
detergents—to manure can dramatically decrease the amount
of the harmful bacterium E. Coli O157:H7 present.xxxi
There are also feed additives for cattle—including one
derived from a type of seaweed which is already widely used in
human foods and cosmetics—that can significantly reduce
the amount of this dangerous strain of E. Coli in cattle manure.xxxii
Another proven and simple way to reduce the presence of
E. Coli in cattle manure is the method of sending them out to
graze on pasture, and taking them off of industrial feed made of corn and other grains.
While feed additives are a creative way to address some
problems, ultimately they do nothing to address the fact that
too much waste is being produced in areas that are too
concentrated. Eliminating E. Coli bacteria does nothing to
address the problems of harmful gases or the presence of
nitrogen and phosphorous in the manure. While methane digesters
can partially reduce the discharge of harmful gasses, they
can’t eliminate the solid waste which still must be stored
and discharged, nor do they protect against leaks or overflows
that can contaminate water supplies.
What You Can Do
It’s clear that the best way to deal with industrial
agriculture’s mountains of manure is to de-concentrate the
animals and likewise de-concentrate their waste. Sustainable,
pasture-based systems allow for the animals to distribute their
waste in amounts that the soil can absorb, without using large
quantities of water for washing or fuel to power trucks for
transportation and spraying. By shopping at small, local
sustainable farms and supporting pasture-based methods of waste
management, we can all encourage change and promote healthier
and more environmentally-friendly farming.
- Use the Eat
Well Guide! Find local farms, stores, and restaurants serving
sustainably-raised meat and dairy products by entering your zip
code.
- If you live near a factory farm and
want to do something about the problems it creates, organize a
local group and read the GRACE Factory Farm Project’s Guide
to Confronting a CAFO.
Did You Know?
- Dairy cows in confined feeding
operations throughout the US produce more than two billion
pounds of manure nitrogen per year.xxxiii
- The most recent Census of
Agriculture shows that there were almost 95.5 million cows and
calves in the United States in 2002.xxxiv There were
also about 60.4 million hogs and pigs,xxxv each
producing waste every day.
For More Information
Sources
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