Performance of a seawater-driven forward osmosis process for pre-concentrating digested sludge centrate: organic enrichment and membrane fouling

Vu, Minh T.; Ansari, Ashley J.; Hai, Faisal I.; Nghiem, Long D.

doi:10.1039/c8ew00132d

Cited by 12 publications

(8 citation statements)

References 33 publications

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“…Flushing the fouled membrane using DI water constitutes the first strategy. A cross-flow velocity (CFV) of 20 cm/s was chosen in our flushing experiments, which is similar to the CFV used by Mi and Elimelech and Vu et al The flow direction was not altered during membrane cleaning. The other two cleaning strategies for OARO focus on osmotic backwashing using different feed and draw solutions.…”

Section: Methodsmentioning

confidence: 99%

Exploring the Limitations of Osmotically Assisted Reverse Osmosis: Membrane Fouling and the Limiting Flux

Peters

et al. 2022

Environ. Sci. Technol.

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Osmotically assisted reverse osmosis (OARO) has shown great potential for low-cost and energy-efficient brine management. However, its performance can be significantly limited by membrane fouling. Here, we performed for the first time a comprehensive study on OARO membrane fouling, explored the associated fouling mechanisms, and evaluated fouling reversibility via simple physical cleaning strategies. First, internal membrane fouling at the draw (permeate) side was shown to be insignificant. Flux behavior in short-term operation was correlated to both the evolution of fouling and the change of internal concentration polarization. In long-term operation, membrane fouling constrained the OARO water flux to a singular, common upper limit, in terms of limiting flux, which was demonstrated to be independent of operating pressures and membrane properties. Generally, once the limiting flux was exceeded, the OARO process performance could not be improved by higher-pressure operation or by utilizing more permeable and selective membranes. Instead, different cyclic cleaning strategies were shown to be more promising alternatives for improving performance. While both surface flushing and osmotic backwashing (OB) were found to be highly effective when using pure water, a full flux recovery could not be achieved when a nonpure solution was used during OB due to severe internal clogging during OB. All in all, the presented findings provided significant implications for OARO operation and fouling control.

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Section: Methodsmentioning

confidence: 99%

Exploring the Limitations of Osmotically Assisted Reverse Osmosis: Membrane Fouling and the Limiting Flux

Peters

et al. 2022

Environ. Sci. Technol.

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“…At this point, the drop in the water flux under the AL-DS mode was quicker, which might be explained due to the combination of dilution and more intense membrane fouling. This observation could be due to the active and SL structure, leading to more severe concentration polarization in the FO mode, which has been investigated in previous works(Ibrar et al, 2020;Vu et al, 2018).Exp3 and Exp4 studied the effect of the flow rate of DI water in the cleaning cycle on the FO process in AL-DS & AL-FS modes. The 40 o C DI water flow rate in the cleaning process was increased to 3 LPM in Exp3 and Exp4.…”

mentioning

confidence: 86%

Brine reject dilution with treated wastewater for indirect desalination

Khanafer

Ibrahim

Yadav

et al. 2021

Journal of Cleaner Production

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The forward osmosis (FO) process was suggested as a pretreatment to a multi-stage flashing (MSF) plant to reduce the environmental impact of brine discharge and the chemicals used.Yet, there is no study investigating the performance of the FO process pretreatment to the MSF plant using tertiary sewage effluent (TSE) as a feed solution. Combining MSF brine with the TSE generates a considerable permeation flux, reducing the membrane area and capital cost. This study evaluated the performance of the FO process for indirect desalination of the MSF brine, considering membrane fouling, cleaning, required membrane area and the specific power consumption. The FO process used a thin-film composite (TFC) membrane to dilute the brine reject from the MSF plant by the TSE and hence converting waste solutions into a feasible water resource. A considerable high water flux (±35 L/m²h) was generated and slightly decreased throughout each experiment's 4 cycles. An enhancement in the water permeability was observed in the FO tests with a prefiltration of the brine reject and the wastewater with 20µm and an osmotic backwash cleaning of the used membrane. The prefiltration of the draw and feed solutions was effective in minimizing the impact of fouling.Maximum power consumption of 0.007 kWh/m³ was consumed in the forward osmosis process without prefiltration and decreased to 0.006 kWh/m³ in the FO process. The proposed FO system successfully diluted the brine reject' divalent ions, reducing their concentration to 43% in some cases. Depending on the FO membrane orientation, the TSE feed solution resulted in a 276% to 473% reduction in the number of FO elements required in the FO process compared to the seawater feed solution.

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“…The draw solution plays a pivotal role in the FO operation by providing the driving force for separation. In Forward Osmosis, water transport across a semi-permeable membrane is due to the osmotic pressure gradient between the draw solution side and the feed solution side [53]. The basic principle is that the osmotic pressure of the draw solution must be higher than the feed side to promote transport of water across the semi-permeable membrane [53,54].…”

Section: Fundamentals Of the Fo Separationmentioning

confidence: 99%

Organic Fouling in Forward Osmosis: A Comprehensive Review

Yadav

Ibrar

Bakly

et al. 2020

Water

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Organic fouling in the forward osmosis process is complex and influenced by different parameters in the forward osmosis such as type of feed and draw solution, operating conditions, and type of membrane. In this article, we reviewed organic fouling in the forward osmosis by focusing on wastewater treatment applications. Model organic foulants used in the forward osmosis literature were highlighted, which were followed by the characteristics of organic foulants when real wastewater was used as feed solution. The various physical and chemical cleaning protocols for the organic fouled membrane are also discussed. The study also highlighted the effective pre-treatment strategies that are effective in reducing the impact of organic fouling on the forward osmosis (FO) membrane. The efficiency of cleaning methods for the removal of organic fouling in the FO process was investigated, including recommendations on future cleaning technologies such as Ultraviolet and Ultrasound. Generally, a combination of physical and chemical cleaning is the best for restoring the water flux in the FO process.

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Performance of a seawater-driven forward osmosis process for pre-concentrating digested sludge centrate: organic enrichment and membrane fouling

Abstract: This study demonstrated the potential of seawater-driven forward osmosis for enriching organic matter in digested sludge centrate.

Cited by 12 publications

References 33 publications

Exploring the Limitations of Osmotically Assisted Reverse Osmosis: Membrane Fouling and the Limiting Flux

Exploring the Limitations of Osmotically Assisted Reverse Osmosis: Membrane Fouling and the Limiting Flux

Brine reject dilution with treated wastewater for indirect desalination

Organic Fouling in Forward Osmosis: A Comprehensive Review

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