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Putting Cow Poop To Good Use


Everybody poops. Cattle poop a lot. This poop is a big problem for farms that have large herds of livestock, mainly because this poop, if not controlled, emits large amounts of methane into the air. Methane is a gas that the Environmental Protection Agency (EPA) has classified as a greenhouse gas, and a potentially harmful one at that. As this easy-to-understand Penn State article explains, the earth has a natural supply of greenhouse gases that are trapped in the atmosphere and help keep the Earth’s surface warm. But as industrialization boomed, as it continues to do, more greenhouse gases (termed for their warming effects similar to a greenhouse you might have in your backyard) increased the already naturally occurring levels found in the atmosphere. The emission of greenhouse gases is one of the causes of global climate change, and reduction of those emissions is a top priority on President Obama’s “let’s make-Earth-a-better-place” to-do list.

Carbon dioxide and methane are the most common greenhouse gases increasingly trapped in the earth’s atmosphere, causing all sorts of problems for climate, ecosystems, and ozone integrity. And while these gases can both occur via natural and man-made sources, the EPA specifically targets livestock manure as a top source of emitted methane, citing that livestock in the United States emit twenty percent of all of the country’s methane emissions. One-fifth of all emitted methane into the air in the US comes from cow farts and, well, poop! (The rest comes from other industrial practices like fracking and gas pipe leaks.) But is there a way to harness this methane in order to not only help the environment but also the profit margins of dairy farms? Mais, oui!

manure lagoon

This is a manure lagoon.| Photo credit: azcentral.com

Large cattle herds produce literally tons of waste. This waste is pumped into acres-large “manure lagoons” which are just what they sound like—huge, watery puddles of chewed-up-and-pooped-out waste that emits not only millions of metric tons of methane per year but a stink that stings the nostrils and can actually cause headaches and other health problems. Some dairy farms in California and Arizona are smelling less stink, however. Dairy farmers with an entrepreneurial spirit (and an extra million dollars to spend on equipment) have found a profitable use for cow manure, their most reliable byproduct. With the help of large machines called digesters that help ferment the waste, these farmers are turning their waste products into renewable energy by capturing the methane into pipes instead of allowing it to emit into the air. Once captured, the methane is an odorless (thank goodness) natural gas, and a profit item for the farms.

In an article posted on azcentral.com, Curt Kaminer—director and manager of the environmental firm Chaple Street Environmental—noted that, “[a]s long as the cows are pooping, we are producing power.” And this is good news for environmentalists and, well, any breathing being living on this planet. Not only does the system of turning manure into renewable energy aid in efforts to reduce greenhouse gas emissions and help reduce the odor from the manure lagoons, but it also helps dairy farm operations run a little smoother. The “digesters” (the “key to converting waste”) separate and extract water from manure, which the farmers can use in their fields, while at the same time create fertilizer-grade manure which is spread on feed crops. Thus, the circle of dairy farm life continues. And the captured methane? Farmers can sell this gas to energy companies in return for “energy credits” and profit to put toward the costly energy requirements to operate a dairy farm. These credits essentially allow farmers to get paid for producing renewable energy and ultimately reducing greenhouse gas emissions.

In his article for the Visalia Times-Delta, reporter Don Curlee cautions that the use of technology like these manure digesters is “still in its infancy, but destined to grow.” The price of the digester technology might be cost-prohibitive for some smaller dairy farms, too, but larger farms that can make the million-dollar investment will be able to profit immediately from the thousands of tons of poop that is a normal part of everyday life on a dairy farm. After all, it happens.

Michelina DelGizzi

Michelina DelGizzi, MS, MPH, is a writer and caseophile based in Boston and Lafayette, La.