Forward osmosis (FO) as a novel membrane separation technology has recently been
investigated in various water treatment applications. The natural mass transfer process
between two solutions driven by the osmotic pressure difference leads to many
operational advantages in the FO process, such as low energy consumption and minimal
fouling problems. It makes FO a feasible technology for the treatment of produced water
(PW). Although previously, the treatment of PW using FO has been investigated, osmotic
backwashing (OB) is not systematically examined for water flux recovery of the PW fouled FO membranes. Moreover, the cleaning of FO membranes used for the
simultaneous treatment of different PW streams was never previously attempted. In this
study, OB was thoroughly investigated for the cleaning of PW-fouled FO membranes.
Also, FO membrane chemical cleaning using SDS and NaOH solutions was examined
too. To investigate OB, the cleaning efficiency of a 60 min OB cleaning protocol was
examined under different FO operating modes in (5 x 20 h) experiments using synthetic
desalter effluent as FO feed solution (FS) and 1.2 M NaCl solution or water-oil separator
outlet (WO) as draw solutions (DS). The AL-FS (active layer facing FS) mode
outcompeted the AL-DS (active layer facing DS) mode, achieving a flux of 12.9 LMH
and 80.1% water reclamation when using WO as a DS. Therefore, this FO configuration 5
was selected when evaluating the cleaning protocols. Moreover, after evaluating different
OB methods, the 30 min OB protocol achieved the highest system efficiency rate of 95%
and was studied for the treatment of real PW streams. The SDS and NaOH chemical
cleaning methods achieved flux recovery rates of 99% and 98% by the end of the third
treatment cycle, respectively, outperforming the 89% flux recovery rate of the optimized
OB protocol. Although the investigated cleaning methods were able to restore the system
performance, a substantial increase in RSF was observed due to mainly irreversible
colloidal fouling. This study demonstrates the feasibility of OB and chemical cleaning in
restoring FO system performance for the simultaneous treatment of PW streams
| Identifer | oai:union.ndltd.org:kaust.edu.sa/oai:repository.kaust.edu.sa:10754/670228 |
| Date | 07 1900 |
| Creators | Alamoudi, Talal |
| Contributors | Ghaffour, NorEddine, Biological and Environmental Science and Engineering (BESE) Division, Pinnau, Ingo, Vrouwenvelder, Johannes S., Saqib Nawaz, Muhammad |
| Source Sets | King Abdullah University of Science and Technology |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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