Multistage osmotically assisted reverse osmosis process for concentrating solutions using hollow fiber membrane modules

Nakagawa, Keizo; Togo, Norihiro; Takagi, Ryosuke; Shintani, Takuji; Yoshioka, Tomohisa; Kamio, Eiji; Matsuyama, Hideto

doi:10.1016/j.cherd.2020.07.029

Cited by 18 publications

(9 citation statements)

References 21 publications

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“…With minimum liquid discharge (MLD), the energy required for concentrating wastewater is still high, typically 20-25 kWh of electrical energy per m 3 of feedwater treated [19]. Novel technologies potentially able to accomplish MLD and ZLD include osmotically assisted RO (OARO) and variations of OARO [20]. However, such technologies are not yet introduced into commercial practice mainly because of the high cost.…”

Section: Environmental Considerations For Desalinationmentioning

confidence: 99%

Renewable Energy Desalination for Island Communities: Status and Future Prospects in Greece

2022

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Energy and water are two of the most important components required to ensure prosperity and sustainable development to societies. This paper aims to review the status of renewable energy desalination for Greek islandic communities, deployed in two axes. The first one reviews the desalination systems state of the art technological solutions, their energy needs, how renewable energy may be employed and finally the cost of renewable energy desalination is investigated. The second axis focuses on Greek islands per se, where the current situation is investigated, potential solutions for meeting the water needs are evaluated, all leading to the proposal of a methodology towards designing an appropriate and applicable approach in addressing the water needs. Finally, a discussion takes place on how such options might be further deployed, particularly regarding the impacts they may produce for the livelihood and the future prosperity of the pertinent communities, and at the same time supporting the energy transition towards the EU Green Deal goals.

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Section: Environmental Considerations For Desalinationmentioning

confidence: 99%

Renewable Energy Desalination for Island Communities: Status and Future Prospects in Greece

2022

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“…Specifically, OARO uses bilateral RO membrane modules, in which spacers are needed on both sides of the membrane to simultaneously maintain channel structures and enhance mass transfer coefficients. , For mitigating the parasitic energy consumption resulting from the cross-flow streams in the module, loose spacers are required. However, loose spacers would cause severe membrane deformation under the applied hydraulic pressure that significantly compromises membrane performance. , Because of the absence of robust bilateral spiral wound RO membrane modules, hollow fiber membrane modules have been used in pilot studies. , However, these cellulose triacetate (CTA) hollow fiber membranes have very low water flux because of the inherent low permeability of the CTA active layer and the large structural parameter of the membrane which induces significant internal concentration polarization . The low water flux of such modules will require a very large membrane area, which will significantly increase the capital cost.…”

Section: Implications and Outlookmentioning

confidence: 99%

“…33,34 Because of the absence of robust bilateral spiral wound RO membrane modules, hollow fiber membrane modules have been used in pilot studies. 35,36 However, these cellulose triacetate (CTA) hollow fiber membranes have very low water flux because of the inherent low permeability of the CTA active layer and the large structural parameter of the membrane which induces significant internal concentration polarization. 37 The low water flux of such modules will require a very large membrane area, which will significantly increase the capital cost.…”

Section: ■ Implications and Outlookmentioning

confidence: 99%

Comparison of Energy Consumption of Osmotically Assisted Reverse Osmosis and Low-Salt-Rejection Reverse Osmosis for Brine Management

Wang

Feng

Chen

et al. 2021

Environ. Sci. Technol.

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Minimum and zero liquid discharge (MLD/ZLD) are emerging brine management strategies that attract heightened attention. Although conventional reverse osmosis (RO) can improve the energy efficiency of MLD/ ZLD processes, its application is limited by the maximum hydraulic pressure (ΔP max ) that can be applied in current membrane modules. To overcome such limitation, novel RO-based technologies, including osmotically assisted RO (OARO) and low-salt-rejection RO (LSRRO), have been proposed. Herein, we utilize process modeling to systematically compare the energy consumption of OARO and LSRRO for MLD/ZLD applications. Our modeling results show that the specific energy consumption (SEC) of LSRRO is lower (by up to ∼30%) than that of OARO for concentrating moderately saline feed waters (<∼35,000 mg/L TDS) to meet MLD/ZLD goals, whereas the SEC of OARO is lower (by up to ∼40%) than that of LSSRO for concentrating higher salinity feed waters (>∼70,000 mg/L TDS). However, by implementing more stages and/or an elevated ΔP max , LSRRO has the potential to outperform OARO energetically for treating high-salinity feed waters. Notably, the SEC of both OARO and LSRRO could be 50% lower than that of mechanical vapor compressor, the commonly used brine concentrator in MLD/ZLD applications. We conclude with a discussion on the practicability of OARO and LSRRO based on membrane module availability and capital cost, suggesting that LSRRO could potentially be more feasible than OARO.

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“…Most recently, CTA-HF membranes have been applied to demonstrate the OARO application because of its high pressure resistance similar to the RO membranes (>70 bar) and the preferable HF configuration which allows two solutions to be introduced at both sides of the membrane [ 34 , 35 ]. Norihiro Togo et al performed OARO concentration tests using a pilot-scale CTA-HF membrane module and a theoretical calculation based on the test results.…”

Section: Current Development In Cta-hf Membranesmentioning

confidence: 99%

“…Cellulose triacetate (CTA)-based hollow fiber (HF) membrane is therefore one of the commercially successful semipermeable membranes that has a long historical development due to its reliable excellent performances especially for drinking water production from seawater. In addition, recently, because of the versatile demands in energy consumption and environmental concerns about brine discharge as mentioned above, CTA-based HFs have caught attention for the usage of different methods, such as forward osmosis (FO) [ 23 , 24 , 25 , 26 ], pressure-retarded osmosis (PRO) [ 11 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ] and brine concentration (BC) [ 34 , 35 ] for the emerging technologies. Because their applications require optimum characteristics individually, different strategies for designing the membrane and module are required in spite of using the same CTA material.…”

Section: Introductionmentioning

confidence: 99%

Cellulose Triacetate (CTA) Hollow-Fiber (HF) Membranes for Sustainable Seawater Desalination: A Review

et al. 2021

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Cellulose triacetate (CTA)-based hollow fiber (HF) membrane is one of the commercially successful semipermeable membranes that has had a long progress since the time the excellent semi-permeable feature of cellulose-based polymers was found in 1957. Because of the reliable and excellent performances, especially for drinking water production from seawater, CTA-HFs have been widely used as reverse osmosis (RO) membranes, especially in arid regions. In this review, recent developments and research trends on CTA-HF membranes for seawater reverse osmosis (SWRO) plants were presented. A flux analytical model, an optimization strategy for chlorine injection without losing salt rejection performance, and a module of current high performance CTA RO membranes along with its plant operation data were updated in this paper. Furthermore, a newly developed CTA-HF membrane for brine concentration (BC) application (called BC membrane) was also addressed. Finally, RO/BC hybrid operation was introduced as an effective SWRO desalination technique that enables minimizing the volume of brine disposal from the RO plant by increasing the recovery ratio and the subsequent amount of produced freshwater, without an additional energy input.

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Multistage osmotically assisted reverse osmosis process for concentrating solutions using hollow fiber membrane modules

Cited by 18 publications

References 21 publications

Renewable Energy Desalination for Island Communities: Status and Future Prospects in Greece

Renewable Energy Desalination for Island Communities: Status and Future Prospects in Greece

Comparison of Energy Consumption of Osmotically Assisted Reverse Osmosis and Low-Salt-Rejection Reverse Osmosis for Brine Management

Cellulose Triacetate (CTA) Hollow-Fiber (HF) Membranes for Sustainable Seawater Desalination: A Review

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