Seawater desalination for agriculture by integrated forward and reverse osmosis: Improved product water quality for potentially less energy

Shaffer, Devin L.; Yip, Ngai Yin; Gilron, Jack; Elimelech, Menachem

doi:10.1016/j.memsci.2012.05.016

Cited by 270 publications

(140 citation statements)

References 35 publications

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“…An FO pilot system with RO regeneration (FO-RO) was used to concentrate low-salinity O&G wastewater [2,18]. FO-RO has also been suggested to be more efficient than RO for seawater desalination [19,20], but other studies have shown that this is unlikely [21,22]. Another FO pilot plant forgoes draw regeneration in favor of "osmotic dilution" [2,18]: the dilution of a pure sodium chloride solution powers the concentration of O&G wastewater.…”

Section: Assessment Of Technologiesmentioning

confidence: 99%

Raising forward osmosis brine concentration efficiency through flow rate optimization

2015

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An exergetic efficiency is defined in order to compare brine concentration processes including forward osmosis (FO) across a wide range of salinities. We find that existing FO pilot plants have lower efficiency than reverse osmosis plants in the brackish and seawater salinity ranges. High salinity FO, in its current form, is still less efficient than mechanical vapor compression. We show that efficiency is the product of FO exchanger and draw regenerator efficiencies, and therefore FO system energy efficiency benefits from improvements to both. The mass flow rate ratio (between draw and feed flow rates) is identified as a crucial parameter in the design of efficient FO systems because of its effect on exchanger efficiency. We demonstrate a method of thermodynamically balancing an FO system by choosing flow rates that lead to equal osmotic pressure differences at both ends of the exchanger, and show the method's potential to increase efficiency by 3-21% based on current system designs.

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Section: Assessment Of Technologiesmentioning

confidence: 99%

Raising forward osmosis brine concentration efficiency through flow rate optimization

2015

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Section: Energy Efficiency and Renewable Energy And Their Industrial mentioning

confidence: 99%

“…Tables Table 1: Hybrid FO--RO systems are demonstrated to produce high quality product water from a va--riety of feed streams with relatively low salinity (e.g., between 500 and 5,000 mg/L) [8, 18--20]. However, if the RO subsystem is the primary means for reconcentrating the draw solu--tion, it both limits the salinity that may be treated due to osmotic pressure limitations of the RO subsystem and is not energetically favorable [20,21].To improve the viability of FO processes for desalination it is preferable to employ alternative means to reconcentrate the draw solution. One alternative method identifies the use of a thermolytic solution consisting of dissolved ammonia and carbon dioxide salts [22,23].…”

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confidence: 99%

Engineered Osmosis for Energy Efficient Separations: Optimizing Waste Heat Utilization FINAL SCIENTIFIC REPORT DOE F 241.3

Hancock¹

2013

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Executive SummaryThe purpose of this study is to design (i) a stripper system where heat is used to strip ammonia (NH3) and carbon dioxide (CO2) from a diluted draw solution; and (ii) a condensation or absorption system where the stripped NH3 and CO2 are captured in con--densed water to form a re--concentrated draw solution.This study supports the Industrial Technologies Program of the DOE Office of Energy Efficiency and Renewable Energy and their Industrial Energy EfficiencyGrand Challenge award solicitation. The study is divided into five primary tasks:• Task 1: Assessment of potential benefits associated with integrated Oasys engi--neered osmosis (EO™) technology into existing water treatment schemes.• Task 2: Selection of operating conditions for pilot design and testing using indus--trial waste heat.• Task 3: Development of a stripper subsystem capable of removing thermolytic solutes to produce high quality product water within the EO system framework.• Task 4: Development of a condensation or absorption subsystem capable of re--capturing draw solution vapor for reuse as draw solution within the EO system framework.• Task 5: Modeling the striper and condenser/absorption system performance us--ing process simulation programs with modified property libraries suitable for Oasys draw solution chemistries.Results from this study show that simulated Oasys draw solutions composed of a complex electrolyte solution associated with the dissolution of NH3 and CO2 gas in water can successfully be stripped and fully condensed under standard atmospheric pressure.Stripper bottoms NH3 concentration can reliably be reduced to < 1 mg/L, even when start--ing with liquids that have an NH3 mass fraction exceeding 6 % to simulate diluted draw so--lution from the forward osmosis membrane component of the process. Concentrated draw solution produced by fully condensing the stripper tops was shown to exceed 6 M--C with nitrogen--to--carbon (N:C) molar ratios on the order of two. Reducing the operating pressure of the stripper column serves to reduce the partial vapor pressure of both NH3 and CO2 in iii solution and enables lower temperature operation towards integration of industrial low--grade or waste heat. Effective stripping of solutes was observed with operating pressures as low as 100 mbar (3--inHg). Systems operating at reduced pressure and temperature re--quire additional design considerations to fully condense and absorb these constituents for reuse within the Oasys EO system context.Comparing empirical data with process simulation models confirmed that several key parameters related to vapor--liquid equilibrium and intrinsic material properties were not accurate. Additional experiments and refinement of material property databases within the chosen process simulation software was required to improve the reliability of process simulations for engineering design support. Data from experiments was also employed to calculate critical mass transfer and system design parameters (such as the height equiva--lent to a theoretical ...

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“…Depending on the source of feed water, however, caution must be taken when it comes to the level of boron (B) and TDS in desalinated water. The B-concentration in irrigation water should be less than 0.50 mg/L, TDS of less than 450 mg/L, and chloride concentration of less than 105 mg/L (Shaffer et al, 2012). Boron in neutral and acidic environments passes through the RO filters and its concentration may reach 2.0 mg/L, which is very toxic to many fruits and vegetables.…”

Section: Opportunities and Challenges Of Adopting Desalination For Agmentioning

confidence: 99%

Use of renewable energy for desalination in urban agriculture in the GCC countries: Possibilities and challenges

Al-Jabri

Ahmed

2018

Jour. Agri. & Mar. Scie.

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The current dependence of the GCC countries on fossil oil and gas is unwise in terms of economic and environmental sustainability. GCC countries must consider the use of renewable energy to cope with price fluctuations of oil and gas in the global market and to lower the emission of green house gases. The demand for food and water in the GCC countriesis increasing due to high growth rate of population. Given the weather conditions and available amounts of natural water resources, the demand on food and water cannot be met unless alternative sources of water are considered. Several studies pointed out that the desalination technology is probably the only option for producing ample amounts of water for food production in arid environments. This work explores the potential of use of desalination technology for producing irrigation water in GCC countries, with special emphasis on experience of the Sultanate of Oman compared with that of Spain. Desalination can always provide a tailored-quality irrigation water at any climatic conditions. The main challenge for considering desalination for agriculture is purely economic; where GCC countries could consider it only if intensive horticulture of high-value cash crops, such as vegetables and flowers in controlled environments, is considered. Disposal of brine water is also a challenge and must be done at an additional cost. Depending on the quality of desalinated water, several studies showed that solar-operated desalination technologies are in a mature stage and economically viable. Therefore, solar energy can make the desalination technology an attractive option to sustain agriculture and food supply in GCC countries.

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Seawater desalination for agriculture by integrated forward and reverse osmosis: Improved product water quality for potentially less energy

Cited by 270 publications

References 35 publications

Raising forward osmosis brine concentration efficiency through flow rate optimization

Raising forward osmosis brine concentration efficiency through flow rate optimization

Engineered Osmosis for Energy Efficient Separations: Optimizing Waste Heat Utilization FINAL SCIENTIFIC REPORT DOE F 241.3

Use of renewable energy for desalination in urban agriculture in the GCC countries: Possibilities and challenges

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