Oil & Natural Gas Projects
Exploration and Production Technologies
Treatment of Produced Waters using a Surfactant Modified Zeolite/Vapor-Phase
The primary goal of this project is to develop a robust treatment system to
efficiently remove organic constituents from produced water in a cost-effective
manner. The process consists of a surfactant modified zeolite (SMZ) system developed
as part of DOE Contract No. DE-AC26-99BC15221, "Treatment of Produced Oil
and Gas waters with Surfactant-Modified Zeolite," combined with a vapor-phase
bioreactor (VPB) developed as part of this research.
University of Texas at Austin
Department of Civil, Architectural, & Environmental Engineering
Department of Earth & Environmental Science
New Mexico Institute of Mining and Technology
The major accomplishment of this work has been the development of a treatment
process for BTEX (benzene, toluene, ethylbenzene, and xylene) removal from produced
water that can yield complete destruction of the BTEX compounds. SMZ adsorption
followed by regeneration has been demonstrated over multiple cycles without
loss of adsorption capacity. The vapor phase bioreactor is capable of treating
the offgas produced during regeneration and operating over the intermittent
cycles of operation that will be required in small-scale systems.
Reuse of produced water will greatly impact production costs in the oil and
gas industry. Estimated produced-water disposal costs per barrel range from
$0.50 to $4.00, based on such factors as transportation, treatment, and reinjection
costs. In the United States, the average production of produced water is 10
barrels of water for each barrel of oil. The BTEX/VPB technology is being designed
as a robust system to facilitate treatment at water disposal sites, thereby
reducing production costs and providing beneficial reuse of the water.
SMZ is an innovative filtration/sorption medium that has been shown to remove
contaminants such as BTEX from produced waters. Cost-effective operation of
an SMZ requires way to regenerate the SMZ onsite. Air-sparging has proven effective
for regeneration; however, this process generates a moist air stream contaminated
with relatively low concentrations of volatile organic compounds (VOCs), including
BTEX. Because these VOCs are biodegradable and present in dilute concentrations,
a vapor-phase bioreactor can be used to destroy the pollutants generated in
the SMZ regeneration step. In VPBs, microorganisms growing on a fixed packing
media are used to biodegrade organic pollutants found in the waste gas stream
being treated. Products of the biodegradation include carbon dioxide, water,
and new biomass. Once the VPB is developed, a series of laboratory and field-scale
experiments are required to optimize the SMZ/VPB combination specifically for
produced water. Furthermore, evaluation and design of the regeneration method
for the SMZ process has not been fully addressed in previous research but will
be a key component in the success of this project.
In this project, researchers:
- Demonstrated that SMZ can be regenerated over a number of cycles without
loss of sorption capacity for BTEX.
- Demonstrated the capability of a VPB to remove BTEX from multicomponent
- Demonstrated that the VPB system can rapidly recover from downtime, thus
enabling periodic operation during regeneration cycles.
- Quantified BTEX desorption from the SMZ during air-stripping regeneration
and developed a correlation that allows prediction of the time required (number
of pore volumes) to achieve regeneration based on the hydrophobicity of the
compound. (This is an essential task for sizing the VPB system.)
- Designed and constructed the field-scale SMZ/VPB system and associated building
at a field site in McGrath, NM, in cooperation with Burlington Resources Inc.
Current Status (June 2006)
Researchers completed construction of the building and reactors for the field-scale
evaluation of the SMZ/VPB system in August 2005. A change in location from a
site in Wyoming to the McGrath location was made to provide the necessary "pilot"
level data for a larger-scale, long-term, follow-on study that was funded based
on the results of this project. A no-cost extension request has been submitted
to allow researchers to complete the field-scale evaluation and summarize the
results of the testing
Project Start: September 12, 2002
Project End: January 31, 2006
Anticipated DOE Contribution: $783,066
Performer Contribution: $241,176 (24% of total)
Other Government Organizations Involved
Los Alamos National Laboratory
NETL - Jesse Garcia (firstname.lastname@example.org or 918-699-2036)
UT Austin- Lynn Katz (email@example.com or 512-471-4244)
Ranck, J.M., Bowman, R.S., Weeber, J.L., Katz, L.E., and Sullivan, E.J., 2005,
BTEX removal from produced water using surfactant-modified zeolite. J. Environ.
Analysis of waste gas composition in the vapor-phase bioreactor.
Pore volumes of produced water.