Aethon draft discharge permit draws wide criticism

The Wyoming Department of Environmental Quality (WDEQ) has received more than 450 public comments on a draft renewal permit. If passed, the permit would allow...
The Wyoming Department of Environmental Quality (WDEQ) has received more than 450 public comments on a draft renewal permit. If passed, the permit would allow operator Aethon Energy to discharge greater volumes of produced water per day from the Moneta Divide field to surface waters.
The public comment period closed July 5, and WDEQ will take several months to assess both technical critiques of Aethon’s permit application and modelling report. Health and safety concerns from residents and businesses downstream of discharge points will also need to be considered.
Since the field came online in the 1960s, produced water has mainly been discharged to the Alkali Creek about 40 miles above the Boysen Reservoir, from which flows the Class-I designated Wind River. However, the renewal application contains a request to expand discharge volumes in line with plans to drill more than 4,000 new wells at Moneta Divide.
Under its current permit, Aethon discharges about 1 million gal/d of water. A portion of this must be treated at the 1.64 million-gal/d Neptune reverse osmosis plant to ensure water does not exceed TDS load limits of 908 tons per month.
The draft permit expands the authorized TDS limit to 2,161 tons per month and adds a monthly chloride limit of 719 tons. WDEQ’s statement of basis provides three different discharge volume scenarios indicating how much water Aethon would have to treat at each level. At 8.27 million gal/d, the highest volume considered, the company would have to treat nearly 5.83 million gal/d of its produced water to remain within load limits. At 2.86 million gal/d, the lowest volume considered, the company would theoretically not have to treat any water, assuming chloride levels were lower than 2,000 mg/L.
Critics say the expansion would violate the Clean Water Act and Wyoming’s environmental quality standards. Bill DiRienzo, head of WDEQ’s water discharge program, maintained to Water in Oil that the increased discharge is unlikely to pose pollution risks because a share of the water will be treated, something that will be restricted by Aethon’s current treatment capacity.
Several environmental groups dispute claims that greater produced water volumes will not degrade surface waters. They are also challenging the legality of the permit’s renewal and expansion based on load limits set prior to WDEQ’s existence and grandfathered in when the department established discharge regulations in 1979.
“[Grandfathering] was a policy that applied to allow for the transition period back in the 70s when the Clean Water Act was first adopted,” Sharon Buccino, land division and nature program senior director at the National Resources Defense Council (NRDC), told Water in Oil. “Aethon wasn’t operating at that point in time, and they’re also asking for a dramatic increase in the amount of discharge, so it’s not just grandfathering what’s already been happening by somebody who has been the operator for a long time.”
To be eligible for grandfathering, Aethon must show that its discharge provides a benefit to local landowners and wildlife. However, according to a June letter submitted by an NRDC-led coalition, the operator did not provide such evidence and failed to demonstrate that its untreated discharge does not contain chemicals from oil and gas operations or offer adequate information regarding the effectiveness of the treatment process for the rest of its discharge.
If the expanded permit is not granted, Aethon would face significant development delays at Moneta Divide and need to find alternatives for the greater volumes of water it would be producing. Expanding its Neptune facility is one option but, as DiRienzo pointed out, that would entail significant investment.
Other options include contracting third parties to truck the water to disposal facilities, finding a site appropriate for deep well injection – an endeavor in which former operator Encana was unsuccessful – or using more recycled water in field operations. Though the company is currently recycling produced water, field reuse would not be able to accommodate the larger volumes that would be produced.

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