Produced water (PW), or water associated with crude oil extraction, is the largest
oily wastewater stream generated worldwide. The reuse and reclamation of these
important water volumes are critical for more sustainable operation in the oilfield.
Ceramic membrane filtration is a promising technology for PW treatment;
however, fouling is the major drawback for a broader application. Fouling leads to
higher resistance to flow, reducing membrane lifetime, and ultimately leading to
higher capital expenditures and operating expenses. Further understanding of the
interactions between PW foulants and the ceramic materials is needed for
designing fouling control strategies and cleaning protocols for ceramic
membranes. This work explored different techniques to characterize, visualize,
and quantify the submicron PW contaminants content and its adsorption
interactions with metal oxides. We visualized and characterized submicron oil
droplets in oilfield PW samples by applying suitable advanced microscopy
techniques. For the first time, crude oil droplets as small as 20 nm were found in
oilfield PW together with other submicron contaminants. The adsorption studies
performed by quartz crystal microbalance with dissipation (QCM-D) showed that
the interactions of organic surface-active compounds with the metal oxides are
driven by the nature of the surfactant and not by the surface properties. This has
implications in the selection of the ceramic membrane material, wherein electrostatic interactions should not be taken as the only predicting factor of
adsorption and fouling during PW treatment. Furthermore, our results suggested
that the more fluid or viscoelastic-like the contaminant layer, the more difficult
the cleaning process from the metal oxide. It demonstrates that the mechanical
property of the attached films is a crucial factor in designing appropriate cleaning
protocols for ceramic membranes. Finally, QCM-D and advanced microscopy
techniques were applied to analyze adsorption and cleaning of contaminants in a
complex Bahraini PW into alumina as a case study. Bacteria were found to attach
irreversibly on the alumina surface, promoting nucleation points for calcium
precipitates. The protocols developed in this work are suitable for understanding
membrane fouling phenomena in the micron scale and could be implemented
before filtration pilot testing to save time and expenses at larger scales.
Date of Award | Nov 2020 |
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Original language | English (US) |
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Awarding Institution | - Biological, Environmental Sciences and Engineering
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Supervisor | NorEddine Ghaffour (Supervisor) |
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- Produced Water
- Membrane Fouling
- Metal Oxide
- Microscopy
- QCM-D
- Adsorption