Environmental Engineering Reference
In-Depth Information
Under the ideal cycle, manure is used to fertilize crops, which are in turn used to feed
the cows. This was the traditional, holistic model used on small family farms. But the
number of small family farms has steadily declined since the Second World War—as of
2002, only 25 percent of US farms were considered family farms—while the number of
CAFOs has steadily risen, due largely to their economies of scale.
Farming is a significant industry. In 2008, US farms held 96 million head of cattle ,
68 million pigs, 9 billion broiler chickens, and 446 million laying hens. Cattle farming
was a $48.6 billion business, while milk production was valued at $34.8 billion, broiler
production at $23.1 billion, and poultry egg production at $8.2 billion. The incentive to
expand these profit centers is large, but they have a significant health and environment-
al cost.
Cows are relentless eaters, and a cow's digestive system, with its series of four stom-
achs, produces a steady stream of manure. Dairy cows are often fed a high-protein
diet, which increases milk production and results in liquid manure that is easier to
spray than solid manure. A single lactating Holstein emits 150 pounds of waste every
day —usually two-thirds wet manure and one-third urine. This is equivalent to the daily
waste of eighteen people. A large farm with four thousand cows will produce some 200
million pounds of manure a year.
Wisconsin had 19 CAFOs in 1992 ; by 2009, the number had leaped to 185, and the
WDNR had 50 new applications under review. In January 2010, state regulators green-
lit Wisconsin's biggest CAFO yet: Rosendale Dairy , a $70 million operation that will
house eight thousand cows and produce 92 million gallons of manure a year—which is
more biological waste than every city in the state other than Madison and Milwaukee
produce in a year.
The largest dairy in the world is hreemile Canyon Farms , a few miles from the
Columbia River, near Boardman, Oregon. The farm promotes itself as “sustainable” and
“green” and claims it contains forty-one thousand head of cattle, though news reports
say the farm contains ity-ive thousand cows and is permitted to contain ninety thou-
sand. This industrial-scale operation is jointly owned by A. J. Bos, of Bakersfield, Cali-
fornia, who runs one of the largest dairy operations in the country, and R. D. Offutt, of
Fargo, North Dakota, one of the largest potato growers in the United States. Threemile
Canyon produces an estimated half a million tons of manure per year.
At times, CAFOs produce so much liquid manure that it overwhelms a farmer's abil-
ity to store it; in that case, he will usually spread it on fields to get rid of it. Not infre-
quently, this excess manure is washed off the land by precipitation. Glen Stahl appar-
ently faced this situation when he sprayed eighty thousand gallons of liquid cattle feces
on the field next to the Tremls' house.
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