title: Passive remediation of coalbed natural gas co-produced water using zeolite.
abstract: Coalbed natural gas (CBNG) co-produced waters can contain sodium (Na(+)) concentrations that may be environmentally detrimental if discharged to receiving bodies of water or applied to land surfaces. A field demonstration and companion laboratory studies were conducted to evaluate the use of a Bear River zeolite (BR-zeolite) for mitigating impacts associated with Na(+) in CBNG waters. Bench-scale kinetic and adsorption isotherm studies were performed to determine both the rate and extent of sodium Na(+) adsorption and assess the effects of bicarbonate (HCO3(-)) and chloride (Cl(-)) anions. Results of these studies showed that the adsorption of Na(+) on BR-zeolite followed the Langmuir adsorption model with maximum adsorption equal to 21 and 18 g Na(+)/kg zeolite with 0.0012 and 0.0006 L/mg Langmuir coefficients (KL) for sodium bicarbonate and sodium chloride, respectively. The kinetics study indicated that the sorption of Na(+) was inversely related to the size of the zeolite particles with significantly greater adsorption for smaller particles. The field demonstration evaluated the effectiveness of BR-zeolite for mitigating infiltration losses from Na(+) in CBNG waters. The field site utilized 12 open boreholes, each installed to a depth of approximately 1.8 m. Each borehole was lined with a 3.0 m long, 15 cm diameter schedule 40 PVC pipe and fitted with an automatic data logging pressure transducer for measuring water levels over time. The BR-zeolite was found to mitigate much of the deleterious effect that high sodium adsorption ratio (SAR = 27 (mol/m(3))(1/2)) CBNG co-produced water had on soil permeabilities.
authors.affiliation: Department of Civil and Architectural Engineering, University of Wyoming, 1000 E. University Avenue, Laramie, WY 82071-2000, United States.
authors.forename: Shashidhar
authors.initials: S
authors.lastname: Belbase
authors.forename: Michael A
authors.initials: MA
authors.lastname: Urynowicz
authors.forename: George F
authors.initials: GF
authors.lastname: Vance
authors.forename: Mohan B
authors.initials: MB
authors.lastname: Dangi
mesh_terms: D052918:Environmental Restoration and Remediation / Q000379:methods*; D007700:Kinetics; D059206:Natural Gas; D018508:Water Purification / Q000379:methods*; D017641:Zeolites / Q000737:chemistry*
chemical_list: D059206:Natural Gas; D017641:Zeolites
keywords: Co-produced water; Coalbed methane (CBM); Groundwater infiltration; Hydraulic conductivity; Sodium adsorption ratio (SAR)