Montalban Oil and Gas Operations has submitted an underground injection control permit application for the conversion of two existing wells.

The permit application is reviewed by the U.S. Environmental Protection Agency, which is accepting public comment on the application through Jan. 24.

The application is to convert two existing Class II underground injection control wells in Pondera County to Class 5 disposal wells.

The wells will be used for injection of industrial wastewater received from the Montana Renewables fuels refinery in Great Falls into the Madison Formation, according to the EPA.

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The EPA is proposing to approve Montalban’s request to convert the existing wells that Montana Renewables would use to inject wastewater generated from renewable feedstocks, which may include but aren’t limited to vegetable oils, animal fats, distiller’s corn oi and used cooking oil, according to the EPA.

If approved, injection will occur into the Mississippian Madison Aquifer formation at depths between 3,428 and 3,538 feet below the ground surface. An aquifer exemption is also proposed in connection to this injection well to expand a previously approved aquifer exemption for the entirety of the Madison formation, according to the EPA.

The wastewater comes from washing crop and beef tallow products, according to Montana Renewables, before they can use them to produce biofuels at the Great Falls facility.

According to Montana Renewables, the washwater is “non-hazardous, non-corrosive and does not contain radioactive materials,” and would then be delivered to Montalban injection wells in Pondera County.

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Montana Renewables said the feedstocks have to be cleaned of organic impurities before use. Those impurities include phosphorus and nitrogen, common salts such as calcium, potassium, sodium and magnesium, and other non-toxic materials.

The company built a pretreatment unit that uses a water-based process mixing feedstock with water and a weak acid, typically citric acid, to remove the impurities, then is pH-neutralized for discharge, according to Montana Renewables.

The company uses city water for the washing and it doesn’t come in contact with any toxic or hazardous materials in the process, according to the company.

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Montana Renewables said water samples have been independently tested to confirm it meets the federal permit requirements and isn’t hazardous.

Currently, Montana Renewables is transporting the washwater to EPA-permitted wells out of state and the company said that using wells in Montana will reduce rail transport and carbon dioxide emissions and keeps economic benefits in the state.

Montalban has advised that based on prior use at their wells, they can handle a capacity of at least 1,750 barrels daily or 73,500 gallons daily, according to Montana Renewables. Each water truck carries 150 barrels or 6,300 gallons and Montana Renewables said they expect a dozen daily trucks.

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Montana Renewables is working with the City of Great Falls and a consultant to complete a treatability study to determine if the washwater can be sent to the city’s water treatment plant. Once the study is complete, the company intends to submit a discharge permit to the city, according to Montana Renewables.

Montana Renewables plans to use the wells until a city discharge permit is approved or another option for onsite processing has been implemented.

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Documents from Montana Renewables and the EPA state that the injection wells won’t impact groundwater.

The public can submit comments to VelRey Lozano by email at lozano.velrey@epa.gov or by phone at 800-227-8917, extension 312-6128 or 303-312-6128.