Treating Natural Gas Storage Produced Waters Using Constructed Wetland Treatment Systems

Johnson, Brenda M. ¹, Ober, Laura E. ², Castle, James W. ², and Rodgers, Jr., John H. ¹

¹Clemson University, Department of Forestry and Natural Resources, Clemson, South Carolina

²Clemson University, Department of Geological Sciences, Clemson, South Carolina

Natural gas storage produced waters vary widely in chemical constituents and concentrations.  An economically viable approach is needed to treat these waters for either discharge or reuse.  Specifically designed, modular pilot-scale constructed wetland treatment systems were built to treat natural gas storage produced waters with salt concentrations ranging from nearly fresh to hyper saline.  Both organic and inorganic constituents were targeted for treatment in these systems.  The performance of these pilot-scale constructed wetland treatment systems was measured against National Pollution Discharge Elimination System permit limits.  The modular approach allowed flexibility to deal with the wide ranging concentrations of organics and inorganics (salts and metals) found in the various natural gas storage produced waters.  Pilot-scale systems provide data regarding the feasibility of this approach for treating gas storage produced waters of various compositions.  Constructed wetland treatment systems are reliable, flexible in design, and can be built, operated, and maintained at lower costs compared to the current treatment methods of reinjection and chemical treatment.  Robust constructed wetland treatment systems designed to treat organics and inorganics are a viable approach for treating natural gas storage produced waters from a variety of gas storage fields.