The state has opened a public comment period for what could be the state’s first landfill licensed to accept low-level radioactive waste that accumulates during oil and gas production.
Secure Energy Services is requesting the permit for its 13-Mile Landfill, which lists an address in Williston on its permit application materials.
Naturally occurring radioactive materials are part of North Dakota’s shale layers, which also include layers that house oil and gas. NORM comes up as solid wastes in varying amounts whenever crude oil and natural gas are extracted. This materials settles out into tank bottoms as a kind of sludge that must be removed before Bakken light sweet crude can be sent to market.
Processing these wastes concentrates them a little more than they were, causing them to become “technologically enhanced.” Hence the waste is referred to as TENORM.
North Dakota has not had any landfills for this material. Most of it has been going across the state line to facilities in northeastern Montana.
In 2016, the North Dakota Department of Health decided to raise the threshold for radioactive materials in landfills to 50 picocuries per gram. The previous limit was 5. The new level was based on the recommended maximum exposure levels for worker safety at facilities that handle TENORM.
A few entities, including Secure Energy, applied for the new radioactive materials permits in 2016, but none were approved. Secure Energy actually submitted their proposal three times before it was accepted.
Solid Waste Program Manager Diana Trussell said it is not unusual for the process to take time, and require multiple submissions.
“We want to get it right before we go out there with it and make sure the site is truly ready to accept what they are proposing to do,” she said.
Among the restrictions, Secure Energy will not be allowed to accept more than 25,000 tons of TENORM material in any given year.
The wastes must be tested prior to being accepted, to verify that they are below the required threshold. These wastes are kept in a holding area while the test is conducted. If the material is higher than allowed, the company that brought it must remove it and then take it to an approved landfill for such wastes out of state.
Another key point in the Secure Energy permit is proper construction of pits for the TENORM. The pits must include appropriate liners to prevent the material from moving off-site.
The company will also be required to monitor the air upwind and downwind of the facility as well as groundwater. The leachate from the pits must be collected and tested at least quarterly as well.
The state can also, at any time, require additional monitoring if needed.
The company must have a dust control plan, and the pits must be covered at least once a day by a minimum of 1 foot of non-TENORM waste.
When the pit is full, its final cover must measure at least 10 foot from the surface of the topsoil. The top three feet of this required cover includes an 18-inch clay liner at least 3 feet below the surface that has been compacted appropriately to prevent penetration by water. If the slope is greater than 15 percent, that liner must be 5 foot down instead of 3. Above the liner, a clay-rich layer is required for the root zone, and above that, there must be at least 6 inches of topsoil to establish native grasses.