SPE Projects, Facilities & Construction
Volume 4, Number 1, March 2009, pp. 1-8

SPE-111515-PA

Engineered Wetland Design and Applications for On-Site Bioremediation of PHC Groundwater and Wastewater

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DOI  More information 10.2118/111515-PA http://dx.doi.org/10.2118/111515-PA

Citation

  • Wallace, S. and Davis, B. 2009. Engineered Wetland Design and Applications for On-Site Bioremediation of PHC Groundwater and Wastewater. SPE Proj Fac & Const  4 (1): 1-8. SPE-111515-PA.

Discipline Categories

  • 2.5.7 Remediation

Summary

Engineered wetlands are an emerging technology for the on-site bioremediation of petroleum hydrocarbon-contaminated (PHC) water. The engineering optimization of natural treatment processes shows that engineered wetlands are a viable alternative to mechanical remediation systems.

An engineered wetland incorporates a horizontal subsurface flow gravel bed reactor, lined with an impermeable liner and equipped with a Forced Bed Aeration™ system to enhance oxygen delivery. Design parameters include biodegradation rate coefficients for petroleum hydrocarbons such as benzene, toluene, ethylbenzene, and xylenes (BTEX), flowrate, hydraulic residence time, and influent and required effluent concentrations.

Three field-scale applications of this technology in North America are presented. The first application is at a pipeline terminal with contact wastewater containing BTEX and ammonia. A horizontal subsurface flow engineered wetland with Forced Bed Aeration™ and a design flowrate of 1.5 m3/d treats BTEX and ammonia to non-detect concentrations at 40% and 80% of the gravel bed length, respectively. The second application is at a former refinery, where a cascade aerator and surface flow wetland (for iron removal) and horizontal subsurface flow engineered wetland with Forced Bed Aeration™ were constructed in 2003 to treat 6,000 m3/d of BTEX-contaminated extracted groundwater. This system reduces benzene concentrations from 300 µg/L (influent) to <10 µg/L (effluent), and is incorporated into a Robert Trent Jones-designed golf course. The third application is at a former refinery where high ferrous iron concentrations (40 mg/L) favor an alternative design. This system, currently being commissioned, treats 1,060 m3/day of iron and BTEX-contaminated extracted groundwater using a cascade aerator, sedimentation pond, surface flow wetlands, and vertical flow oxic limestone drains. Engineered wetlands are achieving performance goals in field-scale applications, and are a robust and sustainable alternative to mechanical remediation systems.

© 2009. Society of Petroleum Engineers

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History

  • Original manuscript received: 16 June 2008
  • Meeting paper published: 15 April 2008
  • Revised manuscript received: 19 August 2008
  • Manuscript approved: 20 August 2008
  • Published online: 5 March 2009
  • Version of record: 5 March 2009