Hongting Zhao and George F. Vance. Renewable Resources, University of Wyoming, 1000 E. University Ave., Laramie, WY 82071-3354
Coalbed methane (CBM) development in the Powder River Basin (PRB) of Wyoming and Montana has increased dramatically in the past 10 years. Management of co-produced CBM sodic water is a major environmental challenge because of its quantity and quality, as well as serious effects on soil properties. The potential utilization of a synthetic zirconium phosphate (ZrP) was examined in this study. It has a cation-exchange capacity (CEC) as high as 6.67 mmol/g. It is found that that one metric tonne (1,000 kg) of Zr-P could remove all the Na+, Ca2+ and Mg2+ and K+ in 220,000 L (~58,000 gallons or 1,400 barrels) of a surrogate CBM water with an initial Na+ of 411 mg/L and a sodium adsorption ratio (SAR) of 30. The spent ZrP can be easily regenerated for reuse without loss of its capacity. The column performance could be well described by a two-parameter model. The use of ZrP would be beneficial if the CBM water contains high amount of HCO3- and CO32-, it not only remove Na+ from water but also reduce the amount of HCO3- and CO32- in water. By coupling the ZrP treatment process with other water treatment processes to further adjust the water quality to desired one (i.e., SAR < 10), it would appears to be an effective and potentially promising technology for maximizing the beneficial use of poor-quality CBNG in the Powder River Basin, Wyoming. Ongoing studies are to optimize the water treatment techniques.