The project will advance the development of a novel membrane technology based on zwitterionic copolymers that can reject key constituents from produced water while maintaining immunity to detrimental and irreversible membrane fouling. These membranes can remove nanoscale oils, greases, colloidal material, heavy metals and dissolved organic molecules without removing salts and dissolved solids, making filtration of highly saline waste streams practical and cost-effective. The project will both optimize the membrane technology for the demanding operational parameters of produced water treatment and verify performance with actual samples in a representative environment and at a commercially significant scale in the Permian Basin.

Zwitterco, Inc. – Woburn, MA 01801
Advisian, a Worley Company – Houston, TX
The Asatekin Laboratory at Tufts University – Medford, MA
Heartland Water Technologies – Hudson, MA
The Brackish Groundwater National Desalination Research Facility (BGNDRF) – Alamogordo, NM
Daniel Shannon – Houston, TX

The complexity of the chemical composition of produced water has historically constrained management strategies to reinjection for disposal or reuse within the oilfield. However, disposal restrictions, fresh water scarcity, and high water-cuts amidst a deficit in disposal capacity and water transport infrastructure are forcing operators to evaluate technologies that enable reuse outside of the oilfield, a practice that is often considered prohibitively expensiveThe complexity of the chemical composition of produced water has historically constrained management strategies to reinjection for disposal or reuse within the oilfield. However, disposal restrictions, freshwater scarcity, and high water-cuts amidst a deficit in disposal capacity and water transport infrastructure are forcing operators to evaluate technologies that enable reuse outside of the oilfield, a practice that is often considered prohibitively expensive.

The proposed project will demonstrate that ZwitterCo’s membrane technology is an improvement over conventional pre-treatment on the fully burdened cost per barrel. This technology focuses on the economically favorable removal of the constituents that would otherwise handicap further treatment efforts like ion exchange, electrocoagulation, and membrane or thermal desalination. For desalination, a prerequisite for recycling produced water in most non-oilfield applications, ZwitterCo pretreatment could enable cost-efficiencies seen in mature zero liquid discharge (ZLD) applications and accelerating the adoption of these technologies in the oilfield and the standardization of beneficial reuse. If successful, this project will demonstrate that produced water can be treated to levels supporting economic beneficial reuse of the water.

• ZwitterCo has demonstrated phenomenal results with their commercial-grade filtration elements. The membrane technology had extremely high recoveries and full membrane recovery upon mild cleaning. These tests were run on multiple challenging applications (e.g., dairy wastewater, manure, bioprocessing).
• ZwitterCo has demonstrated extremely high (99%) water recovery and complete membrane cleanability using actual produced water at a pilot site in Alamogordo, NM, using spiral-wound membrane elements. Total runtime exceeding 500 hours was shown with two 168-hour operation runs at >95% uptime. With process optimization, all water quality objectives were accomplished.
• The ZwitterCo team completed its survey of Permian market conditions and final techno-economic analysis (TEA). As part of this exercise, various desalination pretreatment technologies, both non-membrane and membrane options including ZwitterCo’s, were compared based on levelized capital and operational costs and filtration performance as measured by expected post-treatment water quality. Furthermore, costs associated with total treatment of produced water to desalinated water capable of beneficial use outside of the oil sector were compared across different combinations of pretreatment and desalination technologies. Disposal and transportation costs of produced water, the process concentrate, and desalinated water were also estimated, and the total cost of treatment, disposal, and transport were compared to industry opinions on economic viability determined in our market survey. This holistic analysis indicates both the potential market interest and economic viability of ZwitterCo membrane treatment of produced water, especially when paired with membrane distillation.
• In addition to the TEA, end use applications for desalinated produced water were evaluated based on criteria including water demand, need, environmental and health risks, and proximity to current well activity. Top candidates were determined to be cooling water for local gas fired power plants, cropland irrigation in local irrigation districts, and surface water augmentation to meet the interstate Pecos River compact. Additional applications evaluated but determined to be of low likelihood for implementation included potash mining extraction, rangeland watering, road spreading for dust control, and municipal water use. A final TEA was submitted to the Department of Energy on May 31, 2022.
• Benchtop temperature tolerance was performed on the Mark I copolymer membrane. Chemicals for producing replicable synthetic produced water were procured and synthetic produced water was made up for testing. Testing charters were completed for upcoming work on chemical, synthetic produced water, and temperature tolerance testing. Characterization of three new polymer blend membranes began with scanning electron microscopy (SEM), permeance, and dye rejection analysis.

ZwitterCo has completed all technical work for this project and is currently compiling final reports for Department of Energy review.

$1,249,999.00

$312,501.00

NETL – David P. Cercone (david.cercone@netl.doe.gov or 412-386-6571)
ZwitterCo, Inc. – Christopher Drover (cdrover@zwitterco.com or 617-682-6846)

Final Technical Report  (September 2022)