State limits discharge flows from Aethon Moneta gas field

by Angus M Thuermer Jr., WyoFile.com

Wyoming regulators renewed Aethon Energy’s pollution-discharge permit Friday, requiring the company to meet a September 2024 deadline for more restrictive standards for contaminated water pumped from the Moneta Divide gas- and oilfield and discharged into creeks above Boysen Reservoir.

The Wyoming Department of Environmental Quality’s permit for Aethon Energy Operating, LLC limits chloride concentrations in discharges to 230 milligrams a liter. That’s about a tenth of the historic concentrations dumped from the energy field.

Aethon’s previous surface discharge permit did not include chloride limits designed to protect Badwater Creek, into which the effluent flows, as a cold-water fishery.

The existing Moneta Divide field has discharged flows averaging about 2,200 milligrams of chloride a liter, the DEQ wrote in the permit renewal. Aethon had sought to renew its permit as it and Burlington Resources expand the field by 4,250 wells. 

Under the new permit, Aethon must meet the nearly 10-times reduction in pollutants by Sept. 1, 2024. The company had operated a produced-water treatment facility known as the Neptune Plant that enabled it to discharge more water. That plant “has become inoperable due to some ongoing technical issues,” the DEQ wrote.

The four-year delay in meeting new permit requirements will “allow the permittee time to install additional [produced water] treatment capacity and optimize its output,” the DEQ wrote.

Meanwhile, DEQ is reassessing whether Badwater Creek deserves protection as a “Class 2AB” waterway, the protections given a cold-water fishery. 

Aethon did not immediately respond to a request for comment from WyoFile.

The Wyoming Outdoor Council, which has monitored the DEQ process for several years, wrote WyoFile that its own review would “determine whether any further action may be required,” to protect Boysen Reservoir. 

DEQ had proposed in March 2019 to approve Aethon’s request to renew the permit and allow 2,161 tons of “total dissolved solids,” a month in the gas field discharges. Aethon also sought permission to discharge  more than ten times the amount of chloride the DEQ settled on in the permit issued Friday. 

After facing public opposition and agreeing to seek more input, DEQ rejected Aethon’s request and proposed more stringent requirements. The newly issued permit limits the discharge of total dissolved solids, a pollution metric, to 908 tons a month, less than half the amount requested by Aethon.

“The project is not authorized to increase its effluent output during the upcoming permit term,” which is five years, the DEQ wrote Friday. “This permit renewal caps the salt load output at historic levels (908 tons per month),” the DEQ document reads. That limit remains unchanged,” the DEQ wrote, and is allowed to continue under regulations that protect the Class I waters downstream of Boysen Reservoir. The Town of Thermopolis gets its drinking water from the river about 20 miles below the Boysen dam.

Federal and state regulators protected the Wind River below the dam as a Class I waterway in 1979. Discharges from the gas- and oilfield, which was developed starting in the 1960s, have been “essentially unchanged” since the Class I designation, the DEQ wrote.

As such, the 908 tons a month is grandfathered, DEQ said. The energy-field discharges represent “an allowable background condition” that complies with Class I regulations, the permit reads.

The new permit calls for sampling for Benzene, Toluene, Ethylbenzene and Xylene, volatile organic compounds that are hazardous to human health and become gaseous at ambient pressure. It requires new sampling for trace constituents of well-maintenance and hydraulic-fracturing fluids, additives that are not permitted in the discharges.

The new permit requires monitoring for nitrogen and other compounds in support of the Boysen watershed nutrient management plan. It sets limits on the discharges for temperature, total sulfides, Radium 236+228 plus total recoverable Barium. The new permit limits the concentration of sulfates at 3,000 mg/L.

BLM approval

Aethon and Burlington in August won approval from the U.S. Bureau of Land Management to expand the gas- and oilfield across 327,645 acres northeast of Shoshoni. The federal OK did not answer looming questions regarding the disposal of millions of gallons of produced water necessary to enable recovery of underground gas reserves. 

In the new permit, DEQ wrote that Aethon could discharge more produced water “if salts were removed.” The BLM approved a 48-inch diameter pipeline some 20 or so miles to Boysen Reservoir through which produced water might be pumped, providing the company secured a DEQ permit for that option.

Aethon could construct water treatment plants to enable greater discharges.

Meanwhile, Aethon has again applied to the Wyoming Oil and Gas Conservation Commission to allow it to pump produced water underground into the Madison formation. Aethon failed to win that exemption in the past.

The commission recently agreed to a request from the Powder River Basin Resource Council to postpone a hearing on that issue from October until it meets in November according to an email to a Resource Council representative provided by the group to WyoFile.

Expansion would bring in money

Expansion of the energy field between Shoshoni and Casper is projected to produce about 18.16 trillion cubic feet of natural gas and 254 million barrels of oil over 65 years. Development could bring $71 million a year in federal royalties, $57.6 million a year in Wyoming severance taxes, and $70 million a year in county ad valorem taxes, the BLM has said.

Numerous commenters, including local governments in Riverton and Shoshoni and some legislators, have urged the DEQ to approve Aethon’s original permit renewal request, saying rejection would curtail a potential economic boon. 

DEQ responded to those comments saying that “the intent of this permit is not to restrict drilling but to prevent adverse water quality impacts to the receiving waters.”

Added permit restrictions

Aethon Energy already violated environmental regulations as it dumped Moneta Divide oilfield wastewater, the Wyoming Department of Environmental Quality asserted in a letter in December 2019.

DEQ inspectors found black sediment deposits and foam in Alkali and Badwater creeks and free oil at a discharge point above them. Inspectors identified the black muck, which taints more than 7 miles of Badwater Creek, as iron sulfide.

Aethon promised “to operate in compliance with the existing and future WDEQ permits for Moneta Divide,” Stefanie Scruggs, a company vice president wrote WyoFile in an email earlier this year.

The new permit prohibits the discharge of anything other than trace amounts of “floating solids” or foam and prohibits “visible deposits of iron, hydrocarbons or any other constituent on the bottom or shoreline of the receiving water.”

The permit also calls for erosion controls, to prevent the continued gouging of channels by the dumping of produced water from the energy field.