CHAPTER FOUR
Coalbed Methane Produced Water Management and Beneficial Uses

Coalbed methane (CBM) produced water can be managed as a waste product or put to beneficial use, depending on water quality and quantity, legal and regulatory issues, permitting constraints for discharge and use, the local environment and climate, and economic considerations. This chapter addresses the management of CBM produced water, including options for beneficial use, and provides context for Chapter 5, which addresses effects of CBM produced water on the environment. Chapter 6 reviews specific water treatment options and associated costs for managing CBM produced water.

OPTIONS FOR CBM PRODUCED WATER MANAGEMENT

CBM produced water management includes (1) disposal, storage, or treatment as a waste product of methane recovery or (2) application in one of many beneficial use opportunities, with or without treatment. Several factors, alone or in combination, determine whether CBM produced water is disposed of, stored, treated, and/or put to beneficial use:

  • Produced water quality;

  • Produced water volumes;

  • Reliability of assurances of sustained supply over time;

  • Proximity of location of produced water in sufficient quantities for beneficial use (such as irrigation) to suitable land parcels;

  • Degree of compatibility between produced water quality and potential receiving landscapes, irrigable land parcels, and receiving water bodies;

  • Availability of suitable storage and disposal sites;

  • Legal or regulatory factors concerning the discharge, management, and use of CBM produced water;



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CHAPTER FOUR Coalbed Methane Produced Water Management and Beneficial Uses Coalbed methane (CBM) produced water can be managed as a waste product or put to beneficial use, depending on water quality and quantity, legal and regulatory issues, permit- ting constraints for discharge and use, the local environment and climate, and economic considerations. This chapter addresses the management of CBM produced water, includ- ing options for beneficial use, and provides context for Chapter 5, which addresses effects of CBM produced water on the environment. Chapter 6 reviews specific water treatment options and associated costs for managing CBM produced water. OPTIONS FOR CBM PRODUCED WATER MANAGEMENT CBM produced water management includes (1) disposal, storage, or treatment as a waste product of methane recovery or (2) application in one of many beneficial use op- portunities, with or without treatment. Several factors, alone or in combination, determine whether CBM produced water is disposed of, stored, treated, and/or put to beneficial use: • Produced water quality; • Produced water volumes; • Reliability of assurances of sustained supply over time; • Proximity of location of produced water in sufficient quantities for beneficial use (such as irrigation) to suitable land parcels; • Degree of compatibility between produced water quality and potential receiving landscapes, irrigable land parcels, and receiving water bodies; • Availability of suitable storage and disposal sites; • Legal or regulatory factors concerning the discharge, management, and use of CBM produced water; 

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C O A L B E D M E T H A N E P R O D U C E D WAT E R I N T H E W E S T E R N U . S . • Economics of storage and disposal versus options for treatment and beneficial use; and • Concern on the part of the CBM operator over liability associated with produced water management, including water use, discharge, and transfer. Commercially available water treatment techniques can be employed individually or in combination to attain the water quality to support any beneficial use, but at variable costs ( Veil, 2009; see Chapter 6).1 Disposal and storage options include direct discharge to surface water bodies (depending on produced water quality and quantity and relevant regulations), deep- or shallow-well reinjection and/or storage in surface impoundments, evaporation, and land application. Table 4.1 summarizes the strategies used to manage produced water in the western CBM-producing basins. Two broadly contrasting approaches to produced water management are highlighted in this chapter: (1) the Powder River Basin, where substantial water volumes and relatively low salinity have yielded a variety of options for eventual use of treated or untreated CBM produced water, and (2) the San Juan Basin, where low water volumes and relatively high CBM produced water salinity have made deep-well injection of untreated produced water a standard practice (see Table 2.1; Table 2.2). The volume of water produced annually from Powder River Basin CBM wells is sub- stantially greater than that of any other western basin (see Chapter 2 and Table 2.1). The large number of wells with high water production from relatively shallow depths has thus focused much of the attention regarding management of CBM produced water and its impacts on this basin, particularly the Wyoming portion of the basin where most CBM production currently occurs (Box 4.1). However, as outlined in Chapter 3, within each of the CBM producing basins where water is being brought to the land surface, volume is not the only factor taken into consideration in the context of produced water management. State natural resource and regulatory agency statutes and administrative rules, in addition to U.S. Environmental Protection Agency (EPA) permitting requirements for disposal or beneficial use application, dictate or regulate which disposal and management strategies may be employed by the operators and water management contractors. Existing infrastructure, transportation costs associated with shipment of water, and the present-day value of water all influence the extent to which either treated or untreated CBM produced water is perceived or used as a resource. Because the vast majority of CBM produced water is managed by disposal and storage, very little is currently treated for ben- eficial use. A large majority of the treatment is completed as a requirement for permitted disposal by discharge to surface water. T. Olson and D. Beagle, Exterran Water Management Services, personal communication, August 4, 2009. 1 

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Beneficial Uses TABLE 4.1 Summary of Primary CBM Produced Water Management Strategies in Western Basins Basin Primary Water Management Method Reference San Juan 99.9% reinjected Bryner (2002) Uinta 97% reinjected, 3% evaporated Bryner (2002) Powder 64% surface impoundments, 20% direct D. Fischer, Presentation to the committee, River discharge to streams, 13% for surface Denver, CO, March 30, 2009. (Wyoming) or subsurface irrigation, 3% reinjected Tongue 61–65% direct discharge to streams, Calculated from information provided by A. River 4–5% industrial dust control, 26–30% Bobst, Montana Bureau of Mines and Geology, drainage— for surface and subsurface irrigation, Personal communication, December 21, 2009; of the 5% surface impoundments T. Reid, Montana Department of Environmental Powder Quality, Personal communication, December River 30, 2009; and J. Zupancic, BeneTerra, Inc., (Montana) Personal communication, December 28, 2009. Raton 70% direct discharge to streams, 2% Bryner (2002) (Colorado) surface impoundments, 28% reinjected Raton Nearly 100% reinjected M. Fesmire, Presentation to the committee, June (New 2, 2009; data for 2008 Mexico) Piceance Nearly 100% reinjected; remainder in S.S. Papadopulos & Associates, Inc. (2007); (Colorado) evaporation ponds data through 2006 NOTE: North Dakota is not listed in this table because the state does not currently have any CBM pro- duction. All permitted discharges to ephemeral and perennial drainages in the Montana portion of the Powder River Basin are located in the Tongue River drainage. The Northern Cheyenne tribe has expressed considerable concern about potential impacts of CBM development and produced water management on water resources of the Tongue River drainage (see also Appendix F). Data for water management in this region were pooled from several different sources collected by the committee, each with different levels of detail. Some percentages are thus presented as ranges to reflect the appropriate level of uncertainty. Table 4.2 provides a summary of the most typically used water management methods, treatment requirements and challenges, and possible ancillary benefits. The management methods have been separated very generally into two categories: storage and disposal op- tions and beneficial use options. Note that these categories are not mutually exclusive in that storage and disposal options do have a range of potential ancillary benefits and uses. The remainder of the chapter discusses these methods in detail. 

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C O A L B E D M E T H A N E P R O D U C E D WAT E R I N T H E W E S T E R N U . S . BOX 4.1 CBM Produced Water Management in the Powder River Basin CBM producers in the Wyoming portion of the Powder River Basin store the majority of produced water (about 64 percent) in surface impoundments to allow it to evaporate, to be sprayed into the air to enhance evaporation, or to infiltrate into the shallow subsurface or shallow alluvial aquifers (see figure below; Table 4.1). Twenty percent of the CBM produced water is discharged directly to surface water, either after treatment or without treatment if treatment is not required. Although the CBM produced water in the Powder River Basin generally has the lowest total dissolved solids (TDS) concentrations of all the produced water from the western CBM basins, only 13 percent is put to beneficial use, primarily as managed surface irrigation or subsurface drip irrigation. Use of produced water for subsurface drip irrigation requires an underground injection control (UIC) permit (see Chapter 3), inasmuch as the amount of water applied per unit of land is intentionally controlled to promote drainage below the crop root zone and into shallow alluvial aquifers. Only 3 percent of all Wyoming Powder River Basin CBM produced water is disposed of by deep-well reinjection, which also requires a UIC permit. In the Wyoming por- tion of the basin, 26 million barrels (3,350 acre-feet) of CBM produced water were reinjected in 2008; over the period from 2000 to 2008, 235 million barrels (30,300 acre-feet) were reinjected. In contrast, in 2008 alone in the Wyoming portion of the basin, nearly 77,000 acre-feet of CBM produced water were discharged into surface impoundments, while approximately 15,400 acre feet were directly applied to identifiable beneficial use for irrigation (including managed surface irrigation and subsurface drip irrigation). In the Montana portion of the Powder River Basin, the two principal water management methods are permitted discharge and managed surface irrigation. The majority of produced water (61 to 65 percent) from CBM opera- tions is discharged to surface water bodies, as treated discharge (see figure below); a 2010 Montana judicial ruling now prohibits the discharge of any untreated CBM produced water to any state waters. Managed surface irrigation comprises 26 to 30 percent of the discharge, of which 7 percent is apportioned to UIC subsurface drip irrigation. Impoundments are used for only 5 percent of the CBM produced water in Montana, and recently the Montana Supreme Court has declared the use of impoundments for disposal of CBM produced water to be unconstitutional. Industrial use of the water for dust control constitutes the final 4 to 5 percent of the produced water management. The reason for the differences between the two states regarding the selection of management options for CBM produced water is that Montana currently has only two permitted CBM operations. One of these operations produces more than 95 percent of all produced CBM water in Montana and has a preexisting permit for the discharge of about 61 percent of all its produced water into the Tongue River. Storage and Disposal Options reinJection (deeP-well inJection) CBM produced water in the Raton-New Mexico, San Juan, Piceance, and Uinta Ba- sins is almost exclusively reinjected into deep, geologic formations, as a means of disposal (Table 4.1). This approach is used in these basins because of the characteristically high 

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Beneficial Uses FIGURE Proportional representation of CBM produced water management strategies in the Wyoming and Mon - box 4.1 figure.eps tana portions of the Powder River Basin. The total amount of water produced in the Wyoming Powder River Basin bitmap from CBM extraction in 2008 was approximately 678 million barrels. See also Table 2.1 and Figure 2.8. SOURCES: Adapted from D. Fischer, presentation to the committee, Denver, CO, March 30, 2009; A. Bobst, Montana Bureau of Mines and Geology, personal communication, December 21, 2009; T. Reid, Montana Department of Environmental Quality, per- sonal communication, December 30, 2009; and J. Zupancic, BeneTerra, Inc., personal communication, December 28, 2009. NOTE: Chart for Montana correct until May 2010 when the Montana Supreme Court ruled that all CBM produced water must be treated before discharge to Montana streams and rivers. TDS of the produced water and the relatively low water volume per unit of gas produc- tion (Table 2.1; Table 2.2). Geological formations suitable for reinjection in these basins are also well known from historical data associated with water disposal from traditional oil and gas production wells. Treatment by chlorination to address bacterial contamination is required for UIC purposes for deep-well reinjection of CBM produced water. In some cases, filtration of fine particulate material may be required to minimize structural plugging 

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TABLE 4.2 Commonly Used CBM Produced Water Management Methods, Treatment Requirements and Challenges, and Possible Ancillary  Benefits Management Method Treatment Requirements and Challenges Possible Ancillary Benefits Storage and Disposal Options Subsurface (deep-well) reinjection Chlorination is required by the UIC program to Enhanced hydrocarbon recovery for disposal as Class I, II, or V well addres bacterial contamination Subsurface shallow injection for May require treatment; dictated by UIC permit Aquifer replenishment/storage and/or use as aquifer storage and recovery requirements; may require chlorination, drinking water filtration, pH adjustment Discharge to ephemeral and May require none; dictated by NPDES permit Flow augmentation, habitat restoration, wildlife and perennial streams requirements; could require salinity, sodicity, waterfowl habitat fluoride, barium reductions Surface impoundments Seldom required (Wyoming) Shallow alluvial aquifer infiltration Land-applied disposal through May require pH adjustment; salinity and Rangeland habitat improvement, forage production, water spreading SAR reductions; soil amendments to facilitate shallow alluvial aquifer recharge infiltration Beneficial Use Options Surface irrigation Varies from none to pH adjustment, salinity and Rangeland habitat restoration, streamflow SAR reductions; soil amendments to facilitate augmentation, reduced potential for stream infiltration; ongoing soil quality monitoring dewatering, facilitation of disturbed-lands reclamation (drill sites, coal mining sites, travel corridor reclamation) Subsurface drip irrigation Varies from none to degassing, particulate Shallow alluvial aquifer recharge, salt leaching, filtration, pH adjustment, salinity and SAR increased crop or forage production reductions, chlorination for bacterial control; soil amendments to facilitate hydraulic conductivity

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Livestock watering Dependent on water chemistry, intended Wildlife watering, enhanced forage production, duration of impoundment, opportunity for enhanced rangeland forage utilization as a result of mixing or blending with supplemental water livestock dispersion and reduced travel distances to sources. In some circumstances, elective or water discretionary treatment of water may be voluntarily imposed to lower salinity, reduce concentration of elements known to be toxic or detrimental to livestock health, particularly trace metals Instream flow; habitat Dictated by NPDES permit requirements; may Habitat maintenance, restoration, wildlife-waterfowl- enhancement: treatment and require salinity, sodicity, fluoride, barium fishery habitat, flow augmentation to benefit discharge to streams/wetlands reductions downstream water users Municipal/domestic use, aquifer Dependent on water chemistry and desired Aquifer storage: future municipal and/or domestic storage use, but may require treatment to drinking water supply; metal contaminants may adsorb to water standards; chlorination, particle removal aquifer and lower dissolved concentrations; less filtration evaporative loss than surface reservoir storage Industrial use Varies from no treatment required to reduction Reduced demand for withdrawals from existing water of TDS, bicarbonate, and/or other constituents, supplies and temperature and pH adjustment NOTE: NPDES, National Pollutant Discharge Elimination System; SAR, sodium adsorption ratio; TDS, total dissolved solids. 

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C O A L B E D M E T H A N E P R O D U C E D WAT E R I N T H E W E S T E R N U . S . and facilitate reinjection. Shallow well reinjection is not commonly used in these basins for disposal of CBM produced water but may require treatment under UIC permitting requirements. Although deep-well reinjection is largely used as a disposal method, ancillary benefits may include enhanced hydrocarbon recovery, depending on the formation into which the water is injected, the quality of the produced water, and the water’s age (see Box 2.1). Aquifer replenishment and storage may be an ancillary benefit from shallow-well reinjec- tion, again depending on the formation into which the water is injected (see discussion in Chapter 5). The committee did not find any evidence of adverse effects from deep-well reinjection of CBM produced water and did not know of any cases where shallow-well reinjection was used in the Raton-New Mexico, San Juan, Piceance, or Uinta Basins. discharge to ePhemeral and Perennial streams and surface imPoundments Recalling that the outfall which discharges CBM produced water into a stream or an impoundment usually represents a combination of CBM produced water combined from several CBM wells (a well “pod”) (see also Chapter 3), produced water discharge volumes and concentration of chemical constituents at outfalls may differ from day to day. Treat- ment of the produced water prior to discharge to either ephemeral or perennial streams or impoundments may also be required to meet permitted discharge requirements. The only basins where substantial discharge occurs to ephemeral and perennial streams are the Powder River Basin and the Raton Basin of Colorado. Surface discharge is most common at production wells with high volumes of produced water and low concentra- tions of dissolved solutes (see Chapter 2), although treatment to reduce salinity and other constituents or to manage sodium adsorption ratios (SAR) may be required under the provisions of a state-specific National Pollutant Discharge Elimination System (NPDES) permit. Additional treatment may be required under provisions of an NPDES permit to re- duce fluoride, barium, and/or ammonium concentrations. In many instances in the Powder River Basin, little or no treatment is required to meet NPDES standards because of the low levels of most chemical constituents. Some of the ancillary benefits of discharge of produced water to streams, depending on the quality and timing of the flows, include streamflow augmentation, stream habitat restoration, and wildlife and waterfowl habitat enhancement. Although Table 4.2 identifies possible ancillary beneficial uses associated with discharge of CBM produced water to ephemeral or perennial streams, the committee did not find significant evidence or documentation substantiating intentional streamflow augmentation, habitat restoration, or quantified aquifer recharge using CBM produced water. A substantial majority of the produced water of the Raton Basin in Colorado is cur- rently directly discharged into ephemeral and perennial streams. This practice is due, in part, to the lack of clearly defined regulatory protocols and also because some of the water 

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Beneficial Uses produced in the Colorado portion of the basin is of relatively low salinity, with low TDS concentrations (see Chapter 2). A primary mode for disposal of CBM produced water in the Wyoming portion of the Powder River Basin (64 percent of all CBM produced water; Box 4.1) is discharge of untreated CBM produced water into constructed and existing ponds, constructed storage basins, and lined or unlined impoundments. The purpose of impoundments is primarily to facilitate evaporation or infiltration of produced water into the underlying soil. Ancillary benefits of disposal of CBM produced water in impoundments may be livestock or wild- life watering. In numerous instances in Wyoming, evaporation from these impoundments may be enhanced by atomizing or high-pressure spraying of CBM produced water into the atmosphere above impoundments; atomization cannot occur downstream of the im- poundment and the atomization process is designed to drain atomized water back into the impoundment. Approximately 3,500 impoundments for storage of CBM produced water have been constructed in the Powder River Basin in Wyoming (Fischer, 2005) (see also Chapter 5 for discussion of documented effects to groundwater beneath impoundments). The use of impoundments in other basins is negligible or nonexistent except for temporary storage prior to deep-well reinjection. During the first few years of CBM development in the Wyoming portion of the Pow- der River Basin, operators were permitted either to construct dams in ephemeral channels or modify existing on-channel dams and impoundments for temporary storage of CBM produced water. Recognizing the potential interference of these on-channel impoundments with priority water rights of downstream water rights holders, permitting of impoundments by the State Engineer’s Office may require a bypass around an impoundment to address downstream water rights. In the Powder River Basin, approximately 2,500 impoundments are on-channel (Fischer, 2005). An additional, relatively recent requirement being applied to some off-channel im- poundments is lining with impermeable materials to minimize the amount of water leak- ing from impoundments to shallow alluvial groundwater. Presently, about 200 unlined off-channel impoundments in Wyoming may facilitate infiltration or recharge of underly- ing groundwater (Fischer, 2005). Often, no shallow groundwater is present beneath the impoundments to a depth of several hundred feet so shallow groundwater is thus not recharged or impacted. Specific provisions apply to the location of off-channel impound- ments: they may not be sited within 500 feet of a designated water feature (nor less than 500 feet from the outermost floodplain or shallow channel alluvium), as identified on a U.S. Geological Survey 1:24,000 scale topographic map, including perennial and ephemeral streams, dry washes, marshes, and lakes. New guidelines for construction of impoundments, pre-construction groundwater monitoring, and compliance groundwater monitoring once discharge of produced water into the impoundment has commenced have recently been instituted in Wyoming (see Chapter 3). 

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C O A L B E D M E T H A N E P R O D U C E D WAT E R I N T H E W E S T E R N U . S . The initial quality of water in the impoundments reflects the chemistry of the produced water being discharged to the impoundments, which may or may not have been treated prior to disposal depending upon initial water quality and discharge requirements. However, as numerous studies have shown, impoundment water chemistry generally changes over time, with subsequent increases in salinity and trace element concentration (see Chapter 5). As noted in Table 4.2, some of the proposed ancillary benefits of disposal of CBM produced water in surface impoundments include livestock or wildlife watering, or infiltration to shallow alluvial aquifers. Livestock and wildlife watering are described in the next section under “Beneficial Use Options.” The committee was unable to find documented evidence of measured alluvial aquifer recharge consequent to introduction of CBM produced water to impoundments. land-aPPlied disPosal through water sPreading and managed irrigation During early stages of development of the CBM industry in the Powder River Basin, a technique referred to as “land-applied disposal” was adopted by several of the principal gas and water producers. Land-applied disposal was the term used to describe spreading of large volumes of untreated produced water across agricultural fields using sprinkler irriga- tion systems, with the expectation of increasing rangeland or cultivated forage production while simultaneously disposing of large volumes of produced water. Studies of this practice revealed that the technique was not sustainable in many locations, due to substantial dete- rioration in soil structure caused by the effect of applied salts and sodium on some soils of the basin (see Chapter 5). As a result, operators and water resource managers recognized the need for either preventive or intervention soil management actions, including the use of soil amendments (primarily gypsum as a calcium source and sulfur as an acidifying agent), in order for land-applied disposal to remain sustainable. Subsequently, the technique of land- applied disposal was relabeled as “managed irrigation,” which combines the simultaneous application of amendments2 with water spreading. Irrigation or land spreading of saline-sodic water as a mechanism to use or disperse produced water can be feasible. However, the requirements for management and sustain- ability of this practice are likely to be unachievable in marginally productive areas, in areas where scientific irrigation water management and monitoring have not previously been used, and in areas where irrigated crop production is marginally economical, except when used as a means of water disposal in comparison to water treatment or other water disposal costs. Under careful management, ancillary benefits of land spreading of CBM produced Soil “amendments” such as gypsum and elemental sulfur may be added to agricultural soils to liberate sodium. This 2 release of sodium, accompanied by a supply of calcium, enhances improvement in soil structure, and sodium-affected soils can be restored to agricultural productivity. Soil amendments are sometimes called “soil conditioners.” 00

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Beneficial Uses water are rangeland habitat improvement, increased forage production, and shallow alluvial aquifer recharge. Beneficial Use Options In the arid and semi-arid landscapes of the study area, water, or lack thereof, is often the single most influential factor in land suitability for multiple uses. Under most circum- stances, the addition of water is presumed to result in enhanced landscape quality, whether as a result of increased forage production for livestock and wildlife grazing and habitat, sustained instream flows during dry periods, or sustainability of diverse communities of native plant species. At present, however, little evidence or concerted effort exists to docu- ment that CBM produced water has been put to beneficial use for rangeland, wildlife, or stream augmentation. Although the long-term effects of putting CBM produced water to widespread beneficial use in these specific applications are not known, the next sections describe both known (and practiced) beneficial uses as well as those that are not widely applied or documented. surface irrigation Livestock production is the most economically significant agricultural land use in many locales of the western United States where CBM production has expanded rapidly in the past decade. Most of these areas are characterized by semiarid climates, where evaporative demand far exceeds annual precipitation. Correspondingly, with the exception of stream and river floodplains and mountain valleys, most of the associated landscapes are “rangelands,” dominated by sparsely growing native grasses, forbs,3 shrubs, and drought-tolerant woody plant species. Livestock production is sustained by rangeland and forest grazing, supple- mented by winter feeding of grass and alfalfa hay reserves harvested along stream and river corridors during the summer growing season. Where water of sufficient quantity and quality is available, irrigation has been developed to expand livestock forage production as a source of winter feedstocks. In 2007, Montana and Wyoming produced approximately 6 million tons of hay (for livestock feed) with a gross economic value of nearly $630 million.4 Correspondingly, irrigation is a mainstay of the agricultural industry tied to livestock production in the western United States. Abundant supplies of water with salt concen- trations low enough to meet water quality requirements of irrigated croplands offer the potential to supplement and replace existing water supplies, while doubling or tripling the capacity of arid landscapes to produce feed for livestock. However, neither all water nor all Forbs are herbaceous flowering plants. 3 Statistics are sourced from the National Agricultural Statistics Service, available at www.nass.usda.gov/QuickStats/in- 4 dexbysubject.jsp?Pass_group=Livestock+%26+Animals (accessed January 27, 2010). 0

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C O A L B E D M E T H A N E P R O D U C E D WAT E R I N T H E W E S T E R N U . S . landscapes are of suitable quality to support sustained irrigated agriculture. Water quality, soil compatibility requirements, and agricultural plant tolerances to salinity, including ir- rigation, are provided in Ayers and Westcot (1994). Although the chemical characteristics of CBM produced water vary significantly from discharge point to discharge point, salinity and sodicity are generally the two principal water quality characteristics of significance and concern with respect to irrigation or land-applied disposal of CBM produced water. Concerns have thus been raised regarding widescale potential beneficial use of CBM produced water for irrigation of agricultural crops. Currently, more than 8,000 acres of agricultural cropland, primarily grass and alfalfa, are being irrigated by sprinkler irrigation with CBM produced water in the Powder River Basin. This area comprises approximately 6,000 acres in Wyoming and 2,000 acres in Montana. Only 8 percent of the CBM water produced in the Wyoming Powder River Basin was used for managed surface irrigation in 2008 (approximately 9,167 acre-feet or 71 million barrels; Box 4.1). In Wyoming a permit from the Wyoming DEQ is required for surface irrigation if the produced water is obtained directly from the well head. However, if the produced water derives from a permitted surface impoundment, no permit is currently required for the application of produced water to agricultural fields (Wyoming DEQ, 2009). As noted in Table 4.2, ancillary benefits of using CBM produced water for surface irrigation, under careful management, include rangeland habitat restoration, streamflow augmentation, and reduced potential for stream dewatering (see also Chapter 5 for specific effects). suBsurface driP irrigation A relatively recent development for beneficial use and management of produced wa- ter from CBM production in the Powder River Basin is subsurface drip irrigation (SDI), sometimes also called “horizontal injection.” This system involves uniformly discharging produced water below ground, near the bottom of the root zone in agricultural fields, through a network of buried pipelines. The water is discharged to serve multiple purposes, including cropland irrigation, enhanced salt leaching from the soil profile, disposal of excess produced water, and shallow alluvial aquifer recharge. An SDI system is constructed by installing a network of buried tubing that spreads filtered, treated water uniformly, near the bottom of the root zone. The tubing contains precisely spaced emitters that regulate water flow into the soil. Presently, SDI is being used on irrigated fields ranging in size from 20 to 500 acres. Instead of containment ponds or impoundments, lined surge ponds are built for off- gassing bicarbonate in the produced water. The containment ponds are approximately 2 to 4 acres in area and are about 20 feet deep. The surge pond water level is maintained by the CBM produced water pipeline network. The water is pumped from the surge pond into a small pump house. Degassed produced water is then pretreated according to site-specific 0

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Beneficial Uses chemistry requirements and transported to field valves that release the water to multiple underground tube lines. A 100-acre field may use 3 to 4 million barrels (400 to 500 acre feet) of water in a year. This style of irrigation is employed as a means of increasing crop yields while prevent- ing salt and sodium accumulation in surface soils with a minimum of surface disturbance or surface infrastructure after the subsurface drip system has been installed (BeneTerra, 2010). This style of irrigation has the potential to apply two to three times more water on a particular site than traditional surface irrigation because water is introduced near the bottom of the root zone. Although SDI can be employed year-round and can be scaled to accommodate changing water volumes from CBM wells, the longer-term, finite lifetime of CBM wells and the associated produced water supply are factors to consider with regard to planning these irrigation areas. In the Powder River Basin of Wyoming, SDI is regulated under the UIC program, and permits are required from the Wyoming DEQ; in 2008 about 5 percent of the total amount of CBM water produced was used for UIC SDI (Box 4.1). Monitoring of these SDI areas is being conducted by the USGS and a private company specializing in SDI installation and management. The primary focus of the monitoring efforts has been to determine relationships between SDI water discharge and shallow alluvial groundwater quality. Potential primary environmental and ecological benefits include increased crop or forage production. Although shallow alluvial aquifer recharge may also occur as an ancillary benefit, such recharge is not a specific intention of SDI facilities. The facilities are rather designed to ensure that groundwater and surface waters will not be impaired. livestock and wildlife water suPPlies The capacity of arid and semiarid landscapes to support livestock production is closely associated with the availability, quality, and distribution of livestock-consumable water, although livestock can tolerate a range of contaminants in their drinking water (Ayers and Westcot, 1994). In general, animals can often tolerate elevated levels of salinity if they are allowed the opportunity to gradually acclimate to higher salinity levels and water is avail- able in abundant supply. Water with a TDS level of less than 1,000 mg/L is considered to be suitable as a livestock water source. Water with TDS from 1,000 to 7,000 mg/L can be used as a water source for livestock, although consumption of water having a TDS greater than 5,000 mg/L is often associated with intestinal distress. Produced waters of the Raton, San Juan, Uinta, and Piceance basins typically have TDS concentrations that preclude use of produced waters for livestock watering without treatment or blending with less saline water (see Table 2.2). Numerous CBM projects in the Powder River Basin have created off-channel im- poundments or watering stations to provide untreated CBM produced water as a water 0

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C O A L B E D M E T H A N E P R O D U C E D WAT E R I N T H E W E S T E R N U . S . source for livestock. ALL Consulting (2003) describes an example from the 7 Ranch near Gillette, Wyoming, where livestock are watered from small reservoirs and old heavy-vehicle tires are used as watering tanks. Ancillary benefits of the use of CBM produced water for livestock include enhanced forage production and use by wildlife and waterfowl. instream flow and wetland augmentation A possible ancillary benefit of discharging CBM produced water to streams is enhance- ment of instream flow. As discussed in Chapter 3, instream flow is considered a beneficial use in most western states, and release of CBM produced water to streams, if the quality meets surface water and aquatic life standards, can enhance aquatic environments and increase riparian vegetation, providing habitat for birds and other wildlife. An additional ancillary benefit of instream flow augmentation is increased flow to downstream water users. Discharge of CBM waters to wetlands may also enhance these environments and provide ancillary benefits to waterfowl and wildlife if the water quality meets surface water and aquatic life standards. At present, the only areas where this type of CBM produced water benefit might be realized to any degree are the Powder River Basin and the Colorado por- tion of the Raton Basin. The committee found no referenced evidence that produced water is being managed specifically to achieve these benefits at this time. industrial and municiPal use oPPortunities for Produced water Although constrained by available infrastructure, transportation costs, and costs of treating water, CBM produced water is also a candidate for beneficial or supplemental use in a number of industrial and municipal applications (see Table 4.3). Such industries and municipalities would likely need to be located near methane- and water-producing areas, to assure minimal costs for transporting water. Currently, no CBM produced water in the Powder River Basin of Wyoming is used for municipal or industrial activities other than for dust control at nearby coal mines and on rural graveled roads. The committee is aware of only a few cases in which produced water from any oil and gas activity—not CBM pro- duced water—was used for potable supplies (Stewart, 2006; Stewart and Takichi, 2007; see Box 4.2). As mentioned previously, a small amount of CBM produced water in Montana is used for industrial dust control (Box 4.1). CBM WATER AS A BENEFICIAL COMMODITY? Putting CBM produced water to beneficial use requires an understanding of both quantity and quality issues. Some CBM produced water, for example from the Powder River Basin and some parts of the Colorado portion of the Raton Basin, is suitable for livestock 0

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Beneficial Uses TABLE 4.3 Summary of Industry and Municipal Beneficial Use Options for CBM Produced Water in the Western United States. Sector Beneficial Uses Treatment That May Be Necessarya Coal mining/mineral extraction Dust control, fire control None and suppression, materials transport, mineral processing support, restoration/ reclamation Livestock production/feedlots Livestock watering, cleaning, None management of animal wastes Industrial cooling towers: Facilities cooling TDS, carbonate, bicarbonate coal- and gas-fired electric reduction, pH adjustment generation Vehicle and equipment cleaning Vehicle washing (weed control) None and washing facilities Oil and gas exploration and Facilitating drilling, None extraction waterflooding, secondary recovery, equipment cleaning Fisheries-aquaculture Fish production/rearing areas Managed TDS and constituents, temperature Municipalities Fire control/protection None Municipalities Augmentation of municipal Treatment to regulated standards potable water supplies Whether treatment is necessary is dependent upon the intended use and water quality required for a the use. Presently, for example, treatment of water designated for reclamation/restoration of mined lands or for livestock is not necessary if the quality of the water meets requirements for the desired purpose. In the case of industrial uses and ancillary uses or benefits of CBM produced water, the use of the water is totally elective and any treatment that is imposed is for the purpose of facilitating the use or functionality of the water, but would not be a regulatory requirement. NOTE: The table information indicates opportunities for major industry uses but is not a comprehensive presentation of all possible industrial uses for CBM produced water. Lack of accessibility to and sustain- ability of water supplies for the indicated potential use may limit opportunity for beneficial use. 0

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C O A L B E D M E T H A N E P R O D U C E D WAT E R I N T H E W E S T E R N U . S . BOX 4.2 Making “Bad” Produced Water “Good”: Achieving Augmentation with Water Pro - duced from Oil and Gas Operations—in Wellington, Colorado The potential opportunities for use of produced water are numerous, but few of those opportunities have been realized to any level of significance. One case that represents the extreme in making beneficial use of produced water is that of the community of Wellington, Colorado, and its partnership with an environmental consulting firm from Fort Collins, Colorado. Wellington, a community outside Fort Collins, Colorado has experienced rapid expansion in population over the past two decades, but without similarly increasing the availability of desired municipal water supplies. A combination of drought and senior water rights holders’ demands for water for irrigation have put the city of Wellington in a situation with slowly depleting storages of water in underground aquifers that the city relies on for municipal water. The Wellington project is treating water produced from conventional oil wells as a raw water resource to augment shallow water aquifers to ensure adequate water supplies for holders of senior water rights downstream of Wellington. The process is known as aquifer storage and recovery (ASR). A participating oil company engaged with the environmental consulting firm and Wellington to allow the petroleum operator to increase its oil production, resulting in more produced water than they could adequately manage. The environmental consulting firm agreed to take possession of the “newly produced” water, treat the water, and then use the treated water as an augmentation water source to resupply the aquifer from which Wellington was drawing water for municipal use. The augmentation water mixes with water within the shallow alluvium, down gradient of the Wellington municipal water withdrawal, and subsequently satisfies the water rights of downstream senior water rights holders. One of the unique features of this project, in addition to transforming produced water, which normally would be considered a waste, into “good” water used to satisfy an augmentation requirement imposed on the community of Wellington, is the legal recognition of some produced waters as “new” water, or new water resources for the western United States. In addition, this whole new approach to “produced water” as a beneficial use product and augmentation source of water has tested the premise of the “nontributary” nature of water produced from conventional oil wells, the assignment of ownership of “new” water, and how water resource management and regulatory agencies approach new and novel beneficial use applications of produced water. SOURCES: See Stewart (2006); Stewart and Takichi (2007); Henderson (2007); Veil et al. (2004); and www.netl.doe. gov/technologies/pwmis/techdesc/injectfut/index.html (accessed March 9, 2010). watering and wildlife use and consumption directly after it emerges at the well head with no prior treatment. Other produced water may be of suitable quality for establishing and maintaining wetlands. With current technologies, CBM produced water can be treated to attain the quality necessary to support any beneficial use, but at variable costs. At present, however, water coproduced with CBM has been largely neglected for beneficial use, even where concentrations of dissolved solids and other contaminants are within regulatory guidelines for potable agricultural or livestock use, such as described earlier for parts of the 0

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Beneficial Uses Powder River Basin. With appropriate management, assurances of compatibility between CBM produced water quality, crop sensitivity to salinity, and soil properties, CBM pro- duced water may be used to augment site-specific water supplies for irrigated agriculture in some areas. State regulatory frameworks for environmental management and mineral and water rights have been the greatest influence on the way in which produced water can and has been used in the western states (see Chapter 3). This influence extends to any market value, whether real or perceived, of produced water used for beneficial purposes. Today, western cities look to enhance their water supplies, sometimes at significant cost. The societal and economic costs that may be incurred by not considering CBM water for beneficial use in an arid part of the United States are not usually discussed with regard to CBM produced water management. In concept and on paper, putting CBM produced water to beneficial use would seem to be a desirable and relatively easy objective to achieve. In reality, management or discharge of CBM produced water for the specific purpose of achieving beneficial use is potentially economically burdensome, complex, and challenging. For example, in the case of waterfowl habitat enhancement, either constructing or intentionally augmenting existing ponds and wetland areas by discharging CBM produced water on the landscape typically requires an NPDES permit. The process of preparing and submitting applications for such a permit is both economically burdensome and labor intensive for the applicant. Consideration must be given to the quality of the discharged water, the potential for flooding, seepage to downgradient ephemeral channels or shallow alluvium, alteration in the ecological com- munity resulting from changes in hydrology of the wetland, short- and long-term impacts of discharge on the chemistry of the impounded water, and the longevity or tenure of available supplies of produced water to support waterfowl habitat. Consideration also needs to be given to the potential consequence of discontinuation of the augmentation as CBM production diminishes. Another example might be that of instream flow augmentation and corresponding supplementation of downstream irrigation water sources. Discharge requires an NPDES permit, which might require treatment of discharged water to assure protection of aquatic species. The rigor or level of treatment of water to achieve aquatic species protection may far exceed the treatment level that would be required to support sustainable irrigation—yet both beneficial uses are intended with the same CBM produced water discharge, creating added challenges with regard to permitting, compliance, and economics of managing the CBM produced water. Discharging produced water to an existing stream for the purpose of fisheries enhance- ment could result in blended water that is not of an acceptable quality for downstream ir- rigation uses. The beneficial use opportunity is dictated by the quality in stream. Acceptable quality for one beneficial use may preclude use of the water for other uses, or may even 0

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C O A L B E D M E T H A N E P R O D U C E D WAT E R I N T H E W E S T E R N U . S . impair the water quality with respect to other uses. Each beneficial use has a potentially different acceptable quality—and not necessarily the quality of CBM produced water. Each beneficial use also aligns with a set of criteria, and acceptable or appropriate cri- teria for one beneficial use may be in direct conflict with the criteria for another beneficial use. For instance, in the case of discharging CBM produced water for wildlife habitat en- hancement, research has shown that the chemistry of impounded water changes over time and, consequently, that such water may become deleterious to wildlife health over time. In the case of discharge to a stream to supplement downstream irrigation, existing stream channels reflect a geomorphological evolution, which may be substantially altered by flow augmentation. Additional complications and hindrances are introduced when consideration BOX 4.3 First-Order Estimation of the Market Value of CBM Produced Water Since Production Began in Wyoming Water for domestic use in Denver (as an example) costs on the order of $4,000 per acre-foota for a water right. Lease rates for water with at least a 10-year guaranteed supply sold to urban Denver buyers averaged $5,000 per acre-foot (in 2009 dollars).b As shown in the figure below, the potential value of CBM produced water today, if shipped to Denver, would be on the order of hundreds of millions of dollars per year at current market value. The cost of a 10-inch pipeline needed to move water from Wyoming to Colorado would be about $500,000 per mile. For roughly 400 miles of pipeline (the distance from the CBM producing areas of the Wyoming Powder River Basin to Denver), the approximate cost would be on the order of $200 million. At a supply of 75,000 acre- feet per year, the cost of the pipeline and other related business expenses would be covered inside of one year. These calculations do not include water treatment costs that would have to be borne if the water did not emerge from the well head in the Powder River Basin (or another basin) within regulatory standards for potable water. The energy cost of pumping water at 1,000 gallons per minute (with a lift of about 1,000 feet from the Powder River Basin to Denver would be about $20 per acre-foot assuming a lift cost of 1 cent per kilowatt-hour and 90 percent pump and motor efficiencies).c Even assuming much higher power rates and the construction of pump stations, the power costs appear relatively small. While this type of calculation is intentionally simplistic, it illustrates the value or potential value of a resource, water, which is otherwise largely disposed of in a part of the country that historically suffers from water stress. The complications of this issue are significant and include effects of CBM produced water on groundwater and surface water resources (as discussed in Chapter 5); costs at various parts of the beneficial use chain, including production of the water, water treatment, and any storage or transportation of the water (Chapter 6); the con- sistency or sustainability of the produced water resource supply (Chapter 2); and the regulatory constraints both within and between states (Chapter 3). Of relevance to the discussion is also the fact that CBM produced water has never been considered available for a water right since CBM produced water is not available on a permanent basis. Therefore, CBM produced water at present has no legal ownership that can be assigned or transferred to a vendor which is the current basis for the situation that an operator can treat CBM produced water, but cannot sell it. 0

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Beneficial Uses is given to liability, water rights regulations, and sustainability of supply issues. These cir- cumstances, in addition to the general decrease in volume of CBM produced water over the lifetime of a well, make CBM produced water an uncertainty and only a temporary source of water for beneficial use. This uncertainty contributes to the difficulty of addressing op- portunities for beneficial use. For the purposes of adding some quantitative value to this discussion, the committee attempted to generate a simple answer to the question “What might be the economics of using high-quality CBM produced water as a commodity?” The resulting Fermi calcula- tion illustrates the potential value of the total amount of CBM water produced per year now in the Powder River Basin in Wyoming (see Box 4.3). Fermi-type calculations, even 40 0,00 0,000 30 0,000 350,00 0,000 Value 250,000 Water (acre-ft) 30 0,00 0,000 Dollar Value of CBM Water 200,000 250,0 0 0,000 Acre Feet per Year 200,00 0,000 150,000 150,0 0 0,000 10 0,000 10 0,00 0,000 50,0 00 50,0 0 0,000 0 0 1985 1990 1995 2000 2005 2010 Year of Production FIGURE The blue curve shows to the total acre-feet of CBM produced water from the Wyoming portion of the box 4.2 figure.eps Powder River Basin from the mid-1980s through 2009 (corresponding to the vertical scale on the right-hand side; see Chapter 2). The red curve, corresponding to the vertical scale on the left-hand side of the diagram, shows the calculated potential market value of CBM produced water, if shipped to Denver, using the conservative value of $4,000 per acre-foot for domestic use in Denver for each year. In other words, if all of the produced water from the Wyoming portion of the Powder River Basin in 2009 (about 78,000 acre-feet) was shipped and sold to Denver, the market value of the water would be 78,000 acre-feet x $4,000 per acre-foot = $312 million. This “market value” for the water is greater than the estimated cost of building the water pipeline. See www.waterexchange.com/Deepwater.aspx (accessed March 10, 2010). a See www.bren.ucsb.edu/news/water_transfers.htm (accessed April 27, 2010). b See www.engineeringtoolbox.com/water-pumping-costs-d_1527.html (accessed April 27, 2010). c 0

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C O A L B E D M E T H A N E P R O D U C E D WAT E R I N T H E W E S T E R N U . S . at order-of-magnitude or factor ranges of accuracy, are used to frame issues so they can be easily conceptualized for consideration by different parties in more detail (Harte, 1988; Weinstein and Adam, 2008). The committee emphasizes that Box 4.3 does not provide a comprehensive cost-benefit analysis of potential uses of CBM produced water, but is intended as a tool to facilitate communication about considering options for potential use of CBM produced water as opposed to simply disposing of the water. CHAPTER SUMMARY CBM produced water is currently being managed either as a waste product or as a water resource that can be put to beneficial use, although the management as a waste product far exceeds use of CBM produced water as a beneficial natural resource. Irrespective of which avenue is taken, production, handling, management, and/or disposal of produced water all contribute to the cost of production of CBM (discussed further in Chapter 6). Few instances are reported in the industry or scientific literature wherein CBM produced water constitutes an income stream for energy producers. In concept and on paper, putting CBM produced water to beneficial use would seem to be a desirable and relatively easy objective to achieve. In reality, management or discharge of CBM produced water for the specific purpose of achieving beneficial use is potentially economically burdensome, complex, and challenging. Produced water is a necessary byproduct of CBM extraction, although the amount of water produced per unit of natural gas recovered and the quality of water produced vary significantly among CBM producing basins. Additionally, the amount of water produced per CBM well typically decreases as the life of the well is extended (see Chapter 2). These circumstances make CBM produced water an uncertainty and only a temporary source of water for beneficial use. Thus, although CBM produced water does have a value, and even though its availability is transient, this uncertainty in availability contributes to the difficulty of addressing opportunities for beneficial use. Less than 5 percent of all CBM produced water in the six western states considered here is directly or intentionally beneficially used for irrigation of agricultural lands. With the exception of livestock watering, essentially all other beneficial uses of this water are ancillary or consequential to disposal through discharge—e.g., streamflow augmentation, wildlife and aquatic habitat enhancement, aquifer recharge, and wildlife watering. Nearly 85 percent of all CBM produced water in the Powder River Basin (Wyoming and Montana combined) is disposed of either by storage in constructed impoundments or direct, permitted discharge to ephemeral drainages and perennial streams. This approach to produced water management is driven by large volumes and relatively low salinities of produced water (see Chapter 2) and the regulatory ease and environmental suitability of discharge or storage. 0

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Beneficial Uses This management contrasts with the San Juan, Uinta, New Mexico portion of the Raton, and the Piceance Basins, where essentially all water produced as a consequence of CBM production is disposed of through reinjection to geological formations deep below drinking water supplies or CBM aquifers. This approach to produced water management is driven by small volumes and high salinities of produced water, regulatory ease and envi- ronmental suitability of deep reinjection, and the high costs of treatment to achieve water quality conditions compatible with beneficial use options. The potential economic, ecological, and environment value or benefits of CBM pro- duced water, either in its present state or following necessary treatment, have not been fully evaluated. Intentionally simplistic calculations of the potential economic value of CBM produced water from the Powder River Basin, based on the past 15 years of reported water production, suggest commercial significance of this produced water for municipal purposes. W hile the specific dollar value of the water may change with different input parameters, the intrinsic value of the CBM produced water resides in the fact that it can be used and is irreplaceable. REFERENCES ALL Consulting. 2003. Handbook on Coal Bed Methane Produced Water: Management and Beneficial Use Alternatives. Prepared for Groundwater Protection Research Foundation; U.S. Department of Energy; and National Petroleum Tech- nology Office, Bureau of Land Management. Available at gwpc.org/e-library/documents/general/Coalbed%20Methane% 20Produced%20Water%20Management%20and%20Beneficial%20Use%20Alternatives.pdf (accessed March 4, 2010). Ayers, R.S., and D.W. Westcot. 1994. Water Quality for Agriculture, Irrigation and Drainage. Paper, 29 Rev. 1. Rome, Italy: Food and Agriculture Organization. Available at www.fao.org/DOCREP/003/T0234E/T0234E00.htm (accessed January 27, 2010). BeneTerra. 2010. BeneTerra Subsurface Drip Irrigation for Dispersal of Produced Coalbed Water: The BeneTerra Advan- tage. Pratt, KS: BeneTerra LLC. Available at www.beneterra.com/images/Industries_Served.pdf (accessed January 27, 2010). Bryner, G. 2002. Coalbed Methane Development in the Intermountain West: Primer. Boulder: Natural Resource Law Center, University of Colorado. Available at www.colorado.edu/Law/centers/nrlc/CBM_Primer.pdf (accessed January 27, 2009). Fischer, D. 2005. Potential Groundwater Impacts from Coalbed Methane Impoundments. Presentation to the Wyoming Department of Environmental Quality, Water Quality Division, Third Watershed Stakeholders’ Meeting, Buffalo, WY, November 14. Available at deq.state.wy.us/wqd/wypdes_permitting/WYPDES_cbm/Pages/CBM_Watershed_Permit- ting/Clear_Creek/Clear%20Creek%20Downloads/Clear%20Creek%20Meeting%203/Clear%20Creek%20Don%20Fi scher%20Presentation%2011-14-05.pdf (accessed February 24, 2010). Harte, J. 1988. Consider a Spherical Cow: A Course in Environmental Problem Solving. Herndon, VA: University Science Books. Henderson, K.L. 2007. Utilizing Produced Water Through the Proposed “More Water and More Energy Act of 2007.” Ver- mont Journal of Environmental Law. Available at www.vjel.org/editorials/ED10062.html (accessed January 27, 2010). S.S. Papadopulos & Associates, Inc. 2007. Coalbed Methane Stream Depletion Assessment Study: Piceance Basin, Colo- rado. Prepared in conjunction with the Colorado Geological Survey for the State of Colorado Department of Natural Resources and the Colorado Oil and Gas Conservation Commission. Available at water.state.co.us/groundwater/cbm/ piceance/PICEANCE_DRAFT_FINAL.pdf (accessed February 26, 2010). 

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C O A L B E D M E T H A N E P R O D U C E D WAT E R I N T H E W E S T E R N U . S . Stewart, D.R. 2006. Developing a new water resource from production water. Presentation at the International Petroleum Environmental Conference, San Antonio, TX, October 17-20. Available at ipec.utulsa.edu/Conf2006/Papers/Stew- art_18.pdf (accessed January 27, 2010). Stewart, D.R., and L. Takichi. 2007. Beneficial use of produced water—Water as a valuable byproduct. Presentation at the International Petroleum Environmental Conference, Houston, TX, November 5-9. Available at ipec.utulsa.edu/ Conf2007/Papers/Stewart_74.pdf (accessed January 27, 2010). Veil, J.A. 2009. Regulations and Impediments for Treatment and Beneficial Use of CBM Produced Water. Presentation at the International Petroleum Environmental Conference, Houston, TX, November 2-5. Available at ipec.utulsa. edu/Conf2009/Papers%20received/Veil_Regs.pdf (accessed January 27, 2010). Veil, J.A., M.G. Puder, D. Elcock, and R.J. Redweik, Jr. 2004. A White Paper Describing Produced Water from Production of Crude Oil, Natural Gas, and Coal Bed Methane. Prepared for the National Energy Technology Laboratory, U.S. Department of Energy, under Contract W-31-109-Eng-38. Available at www.ead.anl.gov/pub/doc/ProducedWaters WP0401.pdf (accessed January 27, 2010). Weinstein, L., and J.A. Adam. 2008. Guesstimation: Solving the World’s Problems on the Back of a Cocktail Napkin. Princeton, NJ: Princeton University Press. Wyoming DEQ (Department of Environmental Quality). 2009. Summary of Coalbed Natural Gas Produced Water Treat- ment and Management Facilities, Powder River Basin. Cheyenne, WY. Available at deq.state.wy.us/out/downloads/Pro- duced Water Treatment and Management Facilities, Powder River Basin, April 2009.pdf (accessed March 4, 2010).