SHERIDAN, Wyo. — Ever since developers learned how to tap coal seams in the Powder River Basin for natural gas, they’ve struggled with what to do with the brackish groundwater that comes out first. A fish may be the answer.
Water is being pumped from coal-bed methane wells in rural, northern Wyoming to John Woiwode’s tilapia farm in an area where cattle roam. About 1,300 of the small, pink fish now delight in the water — flipping, flopping and pooping in it.
It’s the squiggles of poop that interest researchers like Woiwode, and whether that waste could help make the water into a more usable asset instead of a pollutant.
“The implications are profound,” said Woiwode, who’s spent the past several years studying the role fish could play in alternate uses for methane waste water. “If there’s a potential to get this whole discharge issue shifted from being an industrial pollutant to an agricultural application, this is very significant.”
Previous research found that using fish manure on crops irrigated with methane waste water could promote plant growth, accelerate the rate at which salt-tolerant plants take up salts and help keep soils from being gummed up by harmful levels of sodium. But if water not used by the plants can seep down below the root zone, and carry the sodium with it, the topsoil is not harmed. Tests using fish manure show that it has exactly that effect.
“Once it’s past the root zone, you have productive soil that can be sustainable for an indefinite period of time,” Woiwode said.
“We would hope this would be a win-win-win for all parties,” Woiwode said.
One of the biggest issues surrounding coal-bed methane development — and hindering it, in some cases — is what to do with all the water. To tap coal-bed methane, large amounts of groundwater must be pumped out to ease the pressure holding the natural gas in coal seams. Depending on the area from which it comes, the water can be salty, and if not treated or monitored closely, the water could damage crops or soil, some experts and conservationists say.
Some companies are treating either the water or soil so farmers and ranchers in the basin can use it for irrigation. But that can be a very expensive option.
Larry Munn, a professor of soil science at the University of Wyoming, said there are no easy answers.
“Most of it is suitable for livestock, as drinking water, but the volume required for that is fairly small compared to the amount (being) produced,” he said.
From pit to plots
For Woiwode’s project, thousands of gallons of coal-bed methane water are being taken from wells dotting a local rancher’s land to the fish facility. A 15-foot wide tank that is home to most of the fish there is heated to a comfortable 83 degrees for optimal growing conditions, he says. Their waste ultimately ends up in a nearby lined pit, where it is mixed with more methane water. This will be used on the test plots.
Dan Smith, interim director of the university’s Sheridan Research and Extension Center and an agronomist involved with the project, said researchers have several goals. One is to see whether the fish manure will minimize salt buildup in soils irrigated with methane water. Another is to see which crops could be grown, or perhaps even thrive, using that method.
“This trial here will tell us a little more about how these things will fare in this type of environment,” he said. If it’s successful, it would still have to be adapted to the particular soils in a given area. Soil types vary widely in the basin.
Marathon Oil Co. operates the wells Woiwode is tapping for the project, and the company’s Dave Searle said the firm is as interested as anyone in the results.
“A lot of people, I don’t think, understand how much science we try to explore,” he said.
Rancher Roger Brinkerhoff, who has land involved in the project, said he’s interested in more beneficial uses for the water.
“If the grass comes back, you’re happy,” he said.
If it works, Woiwode said the project could be a winner for all involved. He said it could lead to higher-value irrigated crops for landowners, provide another water disposal option for energy companies and give his company, AquaMatrix International, another way to raise tilapia.
The market for the small fish is huge, he said. More than 200 million pounds were eaten in the United States last year though just a fraction of that was produced domestically, he said.
Woiwode said his company, which, after years of study, developed a method by which fish could be raised in water from methane wells, is interested in tapping the regional tilapia market. Nearby Sheridan College has a fish processing facility that could be used in the effort, he said.
Not that it will be easy, he said. So far, it will take about 1,000 pounds of fish, which weigh 1.5 to 2 pounds fully grown, to provide enough poop to irrigate just an acre of land. But Woiwode said the work should be economically viable in the future if all parties cooperate, and that the project could provide a sound alternative to storing or wasting the water.
“I don’t see it as the be-all and end-all or the silver bullet,” he said. “We’re trying to build an agronomic model.”
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