Fish waste may hold the answer
By Becky Bohrer
Associated Press
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.
Photos by Becky Bohrer • Associated Press
Water is being pumped from coal-bed methane wells in rural northern Wyoming to John Woiwode's tilapia farm. About 1,300 of the pink fish delight in the water — flipping, flopping and pooping in it.
Researchers are raising a pink variety of tilapia in wastewater from coal-bed methane wells in Wyoming for a project using fish manure for crop irrigation. As for the fish itself, there is a demand for it as food.
It's the squiggles of poop that interest researchers like Woiwode, who want to see if the waste could help make the water into a more usable asset.
"The implications are profound," said Woiwode, who has spent the past several years studying the role that fish could play in alternative uses for methane wastewater. "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."
Woiwode's previous work, in greenhouse tests, showed promise. It indicated that when plants receive methane wastewater containing fish manure, it could help promote growth, increase uptake of sodium into plant tissue and even change the structure of the soil, improving water infiltration.
This is key, he said, because one of the leading concerns with saltier water is that it can harm soil and growing conditions, essentially gumming up or sealing off topsoil. But if water not used by the plants can percolate below the root zone and move the sodium farther down — as the tests using fish manures indicated — this isn't an issue, he said.
"Once it's past the root zone, you have productive soil that can be sustainable for an indefinite period of time," Woiwode said.
He's planning to expand the work to field tests near Sheridan this summer to see if the results can be replicated in heavy clay soils. Researchers plan to plant eight species — some of them salt-loving, others not. A range of water treatments, including spring water and raw methane wastewater, also will be applied.
"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 — has been what to do with 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, the water can be salty, and if not treated or monitored closely, could damage crops or soil, some experts and conservationists say.
Some companies are treating the water or soil so farmers and ranchers can use it for irrigation. But that can be very expensive.
Researcher John Woiwode is experimenting with how different crops are affected by methane wastewater when its composition is made beneficial by fish manure.
Other options include discharging the water into streams, which requires a permit; building livestock ponds; and keeping it in large pits. Jill Morrison, an organizer with the Powder River Basin Resource Council, a conservation group, said it is difficult to deal with all the water, given the sheer volume of it and the rate of development in the mineral-rich region.
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.
For Woiwode's project, thousands of gallons of coal-bed methane water are being taken from wells dotting a ranch and transferred to the fish facility. A 15-foot-wide tank that is home to most of the fish there is heated to 83 degrees for optimal growing conditions, he said. Their waste ultimately is stored in a lined pit outside, which also contains excess methane wastewater, for use on the test plots.
Dan Smith, interim director of the university's Sheridan Research Extension Center and an agronomist involved with the project, said researchers have several goals. Those include seeing whether fish manure minimizes salt buildup in soils irrigated with methane water and which crops could be grown, or perhaps thrive, by that method.
Marathon Oil Co. operates the wells being tapped for the project, and the company's Dave Searle said the firm is as interested as anyone in the results.
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 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 of tilapia were eaten in the U.S. last year, but just a fraction of that was produced domestically, he said.
