Osmotically-Assisted Reverse Osmosis (OARO) membrane solutions and technologies for the concentration of highly saline streams
- Persons involved: Onur Kaan Aydın (PhD), Gerrald Bargeman (promotor), Sander Haase (co-promotor)
- Duration: 2024-2028
- Funding: TKI Energie & Industrie, via project Odysseus formed by the consortium UTwente, Nobian, Shell, Lenntech, Colubris and ISPT
Introduction
Highly saline wastewater is produced by multiple industries including the oil and gas industry, chemical industry, desalination industry, and pharmaceutical industry. Often, the effluent forms a brine and has a high (>55 g/L) content of dissolved solids with the main component being sodium chloride [1]. As brine discharge is costly and has negative effects on the environment [2], and because the salt and water in the brine are valuable resources for recycling, it is desired to recover both water and salt from the brine. However, conventional thermal methods of brine separation are highly energy intensive [3]. Moreover, membrane separation methods such as high pressure RO cannot be applied due to the excessively high transmembrane pressures that are required to overcome the osmotic pressure difference between the highly saline concentrate and the clean permeate (water) [4]. Osmotically assisted reverse osmosis (OARO) is a potential alternative technology that lowers the required transmembrane pressures by utilizing a saline draw solution on the permeate side [5]. OARO will be explored further as an alternative method for recovering water and salt from saline wastewater streams by concentrating brine up to saturation levels (25w%).
Key words
Desalination, Membrane, Brine, Osmotically Assisted Reverse Osmosis
Technological/Scientific challenges
Known challenges for OARO involve the high pressure requirements for certain operational domains, flux losses due to concentration polarization [6], and scaling and fouling. However, none of these issues are unique to OARO, and methods utilized in other membrane processes for the management of the same problems will be applied.
Research goals/questions
The aim of this study is to investigate, design and optimize an OARO brine separation process capable of concentrating salt solutions into saturated brine. The process also should have a specific energy consumption that can compete with mechanical vapor recompression (<20 kWh/m3). For this purpose, both lab- and module-scale experiments will be performed.
Figure: Brine Reflux OARO Cascade Splitting Salt Solution [5].
References
- A. Panagopoulos, “Study and evaluation of the characteristics of saline wastewater (brine) produced by desalination and industrial plants,” Environmental Science and Pollution Research, vol. 29, no. 16, pp. 23736–23749, Apr. 2022, doi: 10.1007/s11356-021-17694-x.
- A. Panagopoulos, K. J. Haralambous, and M. Loizidou, “Desalination brine disposal methods and treatment technologies - A review,” Science of the Total Environment, vol. 693. 2019. doi: 10.1016/j.scitotenv.2019.07.351.
- L. M. Vane, “Water recovery from brines and salt‐saturated solutions: operability and thermodynamic efficiency considerations for desalination technologies,” Journal of Chemical Technology & Biotechnology, vol. 92, no. 10, pp. 2506–2518, Oct. 2017, doi: 10.1002/jctb.5225.
- A. Anvari et al., “What will it take to get to 250,000 ppm brine concentration via ultra-high pressure reverse osmosis? And is it worth it?,” Desalination, vol. 580, p. 117565, Jul. 2024, doi: 10.1016/j.desal.2024.117565.
- G. Bargeman, “Creating saturated sodium chloride solutions through osmotically assisted reverse osmosis,” Sep Purif Technol, vol. 293, p. 121113, Jul. 2022, doi: 10.1016/j.seppur.2022.121113.
- Y. K. Chong, D. F. Fletcher, and Y. Y. Liang, “CFD simulation of hydrodynamics and concentration polarization in osmotically assisted reverse osmosis membrane systems,” Journal of Water Process Engineering, vol. 57, p. 104535, Jan. 2024, doi: 10.1016/j.jwpe.2023.104535.