Demonstration-Scale Constructed Wetlands for Produced Waters, Lightburn Station (Natural Gas Storage and Pumping Facility)

Client: Gas Storage Technology Consortium, U.S. DOE, Dominion Transmission, Inc.

Summary: Innovative designs for dealing with industrial wastewater and stormwater quality are an evolving science. Cardno ENTRIX has teamed with local universities in order to provide clients with innovative and progressive designs utilizing results from active research programs involving treatment wetlands for industrial and domestic wastewater and stormwater.

Cardno ENTRIX is an active team member providing engineering support and technical oversight for demonstration-scale constructed wetlands designed to treat produced waters from gas storage and pumping operations. Water produced by the natural gas recovery process from underground storage features contains hydrocarbons and metals as well as exhibiting high levels of chlorides. Those produced waters are presently transported to off-site treatment facilities at considerable expense. The objective of this project is to verify the results of pilot testing performed at Clemson University and to develop design parameters for a full scale application of constructed wetlands as a low cost, on-site treatment process that can result in an acceptable surface discharge of treated produced waters. Treatment objectives for the wetlands include removal of organics and potentially problematic metals such as copper, zinc, and arsenic from gas storage produced waters containing elevated levels of chloride. Due to the location and elevation of the facility, the wetland will be enclosed in a greenhouse to enhance performance during the colder months. As part of the project team Cardno ENTRIX developed design criteria, collected example vendor information, and obtained prices for the required equipment. Cardno ENTRIX also prepared schematics, engineering drawings, and a construction sequence for the installation of the proposed demonstration-scale constructed wetland system. The system will be constructed during the spring of 2006 and operate through the last quarter of 2006 and first quarter of 2007.