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Water: Industry Effluent Guidelines

Coalbed Methane Extraction (CBM)

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Based on the findings from EPA’s multi-year study of the Coalbed Methane Extraction industry, EPA plans to initiate rulemaking for this industry. Coalbed methane extraction is not currently regulated under the Oil and Gas Extraction category (40 CFR 435); however, EPA considers CBM extraction a potential new subcategory of the Oil and Gas Extraction category. EPA’s decision to initiate rulemaking is largely driven by coalbed methane-produced water discharges that can impact receiving surface waters and soils. Saline discharges from coalbed methane operations can adversely affect aquatic life. Technology options for adequately removing pollutants from produced water are readily available.

EPA’s decision to proceed with a rulemaking was announced in the final 2010 Effluent Guidelines Program Plan. Preliminary estimates based on EPA survey data predict that approximately 47 billion gallons of produced water are pumped annually from coal seams across the country. Approximately 45% of those produced waters are directly discharged to waters of the U.S., for a total national discharge of 22 billion gallons per year. Further information regarding discharges from coalbed methane operations can be found in the report for EPA’s study, "Coalbed Methane Extraction: Detailed Study Report" (PDF). (91 pp, 168MB; EPA-820-R-10-022).

What is Coalbed Methane Extraction?

Methane gas is naturally created during the geologic process of converting plant material to coal (coalification). To extract the methane, coalbed methane operators drill wells into coal seams and pump out ground water. Removing the ground water from the formation is necessary to produce coalbed methane, as the water removal reduces the pressure and allows the methane to release from the coal to produce flowing natural gas. In 2008, 252 coalbed methane operators managed approximately 55,500 coalbed methane wells in the U.S. in 13 distinct regions, called basins.

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What is coalbed methane produced water?

The ground water that has been pumped out of the well, called "produced water," like most ground water found deep below the surface of the earth, has high salinity and can include pollutants such as chloride, sodium, sulfate, bicarbonate, fluoride, iron, barium, magnesium, ammonia, and arsenic.

A single coalbed methane well can discharge thousands of gallons of produced water per day, and may discharge produced water for anywhere from 5 to 15 years. Coalbed methane wells have a distinctive production history characterized by an early stage when large amounts of water are produced to reduce reservoir pressure which in turn encourages release of gas; a stable stage when quantities of produced gas increase as the quantities of produced water decrease; and a late stage when the amount of gas produced declines and water production remains low.

The quantity and quality of produced water varies from basin to basin, within a particular basin, from coal seam to coal seam, and over the lifetime of a coalbed methane well. For example, coalbed methane produced water volumes range from 1,000 gallons per day per well in the San Juan Basin (Colorado/New Mexico) to 17,000 gallons per day per well in the Powder River Basin (Wyoming/Montana). Of the 22 billion gallons of water discharged to surface water each year some has high total dissolved solids.

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How do Coalbed Methane Extraction operators currently manage produced water?

Coalbed methane extraction operators need to dispose of thousands of gallons of produced water per day for each coalbed methane well. Operators can employ a range of options for treatment and management of this wastewater.

Preliminary estimates based on EPA survey data predict that approximately 47 billion gallons of produced water are pumped annually from coal seams across the country. Approximately 45% of those produced waters are directly discharged to waters of the U.S., for a total national discharge of 22 billion gallons per year.

Surface water discharge is most prevalent in three U.S. coalbed methane basins: the Black Warrior Basin in Alabama and Mississippi (11% of total coalbed methane surface discharges), the Powder River Basin in Wyoming and Montana (72% of total coalbed methane surface discharges), and the Raton Basin in Colorado and New Mexico (11% of total coalbed methane surface discharges). Limited wastewater treatment is being done on discharges at present. Discharge to surface water occurs rarely, if at all, in the other major commercial basins.

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Coalbed Methane Extraction industry Detailed Study

Information about data collected and findings of the EPA study of the Coalbed Methane Extraction industry can be found in the final study report, "Coalbed Methane Extraction: Detailed Study Report" (PDF). (91 pp, 168MB; EPA-820-R-10-022). This report includes:

  • Summary of data collection activities (including an industry survey)
  • Technical and Economic Profile of the Coalbed Methane Extraction Industry
  • Environmental Assessment Considerations

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Questionnaires for the Coalbed Methane Extraction industry

In 2009 EPA collected data using two instruments: a screener questionnaire and a detailed questionnaire. The screener questionnaire focused on identifying CBM projects, which are the critical business units within the CBM industry that cannot be identified using publicly available information. A project is defined as a well, group of wells, lease, group of leases, or some other recognized unit that is operated as an economic unit when making production decisions. The detailed questionnaire focused on obtaining detailed data at the project level. EPA received approval for the Coalbed Methane Extraction Sector Survey on February 18, 2009, from the Office of Management and Budget (OMB Control No. 2040-0279). The following forms are provided as a reference on the data it collected from industry.

Detailed Survey

Screener Survey

Federal Register Notice Documents

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Rulemaking Schedule

EPA plans to propose a rulemaking for Coalbed Methane Extraction industry in 2013.

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How to Get Additional Information/Contacts

More information on EPA's Detailed Study on Coalbed Methane Extraction is provided in the following documents.

For additional information regarding Coalbed Methane Extraction effluent guidelines, please see the Coalbed Methane Extraction contacts.

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