CHEYENNE, Wyo. (AP) — A well being drilled at the HollyFrontier Corp. refinery in Cheyenne will assess whether the company will be able to dispose of selenium-tainted wastewater by injecting it deep underground.
The company has been discharging the wastewater into Crow Creek, a small stream that meanders through Cheyenne and south into Colorado. Selenium levels in the wastewater have been averaging several times higher than the state's standard for selenium in surface water, according to the state Department of Environmental Quality.
If the geology is conducive to injection, the well will be permitted as a type allowed to dispose of either hazardous or nonhazardous waste, said John Passehl, underground injection supervisor for the Department of Environmental Quality.
In this case, the selenium concentrations are below the level considered hazardous but too high for Crow Creek, which the state has deemed impaired for its selenium levels. The selenium pollution is a byproduct of oil refining.
"It's basically nonhazardous effluent. Nothing you'd want to drink, of course. It allows people to get rid of waste that they otherwise would have to treat to high standards," Passehl said.
Refinery manager Kevin Burke and Julia Heidenreich, a spokeswoman for Dallas-based HollyFrontier, did not return messages seeking comment.
Long-term exposure to high levels of selenium in drinking water can cause hair and fingernail loss and circulation problems, according to the U.S. Environmental Protection Agency.
The well is being drilled by a large, petroleum-industry-type rig at the refinery site. The pilot well will be drilled to a depth of 6,100 feet.
How much wastewater the well might inject underground isn't known yet. The amount will depend on the local geology and how the testing goes, Passehl said.
A nearby city wastewater treatment plant releases a much smaller amount of selenium into Crow Creek, according to a consultant's report for the Department of Environmental Quality earlier this year.
The treatment plant is unable to clean up the refinery wastewater, said Bill DiRienzo, Wyoming Pollutant Discharge Elimination System manager.
"The city can only accept so much selenium from them," DiRienzo said.