Ali, SM, Kim, JE, Phuntsho, S, Jang, A, Choi, JY & Shon, HK 2018, 'Forward osmosis system analysis for optimum design and operating conditions.', Water research, vol. 145, pp. 429-441.View/Download from: UTS OPUS or Publisher's site
Low energy consumption and less fouling propensity of forward osmosis (FO) processes have been attractive as a promising water filtration technology. The performance of this process is however significantly influenced by its operating conditions. Moreover, these operating parameters have both favourable and adverse effects on its performance. Therefore, it is very important to optimize its performance for efficient and economic operation. This study aims to develop a software to analyze a full-scale FO system for optimum performance. A comprehensive theoretical framework was developed to estimate the performance of FO system. Analysis results were compared with the experimental results to validate the models. About 5% deviation of simulation results and the experimental findings shows a very good agreement between them. A novel optimization algorithm was then developed to estimate the minimum required draw solution (DS) inlet flowrate and the number of elements in a pressure vessel to attain the design objectives (i.e. desired final DS concentration and recovery rate at a specific feed solution (FS) flowrate). A detailed parametric study was also conducted to determine the optimum operating conditions for different objectives. It showed that for a specific design objective, higher recovery rate can be achieved by increasing the DS flowrate and number of elements in a pressure vessel. In contrast, lower final concentration can be obtained by lowering the DS flowrate and increasing the number of elements. Finally, a MATLAB based software with graphical user interface was developed to make the analysis process easier and efficient.
Kim, JE, Phuntsho, S, Ali, SM, Choi, JY & Shon, HK 2018, 'Forward osmosis membrane modular configurations for osmotic dilution of seawater by forward osmosis and reverse osmosis hybrid system.', Water research, vol. 128, pp. 183-192.View/Download from: UTS OPUS or Publisher's site
This study evaluates various options for full-scale modular configuration of forward osmosis (FO) process for osmotic dilution of seawater using wastewater for simultaneous desalination and water reuse through FO-reverse osmosis (RO) hybrid system. Empirical relationship obtained from one FO membrane element operation was used to simulate the operational performances of different FO module configurations. The main limiting criteria for module operation is to always maintain the feed pressure higher than the draw pressure throughout the housing module for safe operation without affecting membrane integrity. Experimental studies under the conditions tested in this study show that a single membrane housing cannot accommodate more than four elements as the draw pressure exceeds the feed pressure. This then indicates that a single stage housing with eight elements is not likely to be practical for safe FO operation. Hence, six different FO modular configurations were proposed and simulated. A two-stage FO configuration with multiple housings (in parallel) in the second stage using same or larger spacer thickness reduces draw pressure build-up as the draw flow rates are reduced to half in the second stage thereby allowing more than four elements in the second stage housing. The loss of feed pressure (pressure drop) and osmotic driving force in the second stage are compensated by operating under the pressure assisted osmosis (PAO) mode, which helps enhance permeate flux and maintains positive pressure differences between the feed and draw chamber. The PAO energy penalty is compensated by enhanced permeate throughput, reduced membrane area, and plant footprint. The contribution of FO/PAO to total energy consumption was not significant compared to post RO desalination (90%) indicating that the proposed two-stage FO modular configuration is one way of making the FO full-scale operation practical for FO-RO hybrid system.
Kim, JE, Phuntsho, S, Chekli, L, Choi, JY & Shon, HK 2018, 'Environmental and economic assessment of hybrid FO-RO/NF system with selected inorganic draw solutes for the treatment of mine impaired water', Desalination, vol. 429, pp. 96-104.View/Download from: UTS OPUS or Publisher's site
© 2017 Elsevier B.V. A hybrid forward osmosis (FO) and reverse osmosis (RO)/nanofiltration (NF) system in a closed-loop operation with selected draw solutes was evaluated to treat coal mine impaired water. This study provides an insight of selecting the most suitable draw solution (DS) by conducting environmental and economic life cycle assessment (LCA). Baseline environmental LCA showed that the dominant components to energy use and global warming are the DS recovery processes (i.e. RO or NF processes) and FO membrane materials, respectively. When considering the DS replenishment in FO, the contribution of chemical use to the overall global warming impact was significant for all hybrid systems. Furthermore, from an environmental perspective, the FO-NF hybrid system with Na 2 SO 4 shows the lowest energy consumption and global warming with additional considerations of final product water quality and FO brine disposal. From an economic perspective, the FO-NF with Na 2 SO 4 showed the lowest total operating cost due to its lower DS loss and relatively low solute cost. In a closed-loop system, FO-NF with NaCl and Na 2 SO 4 had the lowest total water cost at optimum NF recovery rates of 90 and 95%, respectively. FO-NF with Na 2 SO 4 had the lowest environmental and economic impacts. Overall, draw solute performances and cost in FO and recovery rate in RO/NF play a crucial role in determining the total water cost and environmental impact of FO hybrid systems in a closed-loop operation.
Volpin, F, Fons, E, Chekli, L, Kim, JE, Jang, A & Shon, HK 2018, 'Hybrid forward osmosis-reverse osmosis for wastewater reuse and seawater desalination: Understanding the optimal feed solution to minimise fouling', Process Safety and Environmental Protection, vol. 117, pp. 523-532.View/Download from: UTS OPUS or Publisher's site
© 2018 Institution of Chemical Engineers To enhance the seawater desalination energy efficiency forward osmosis – reverse osmosis (FO-RO) hybrid system has recently been developed. In this process, the FO “pre-treatment” step is designed to use seawater (SW) as draw solution to filter the wastewater (WW) while reducing the seawater osmotic pressure. Thereby reducing the operating pressure of the RO to desalinate the diluted SW. However, membrane fouling is a major issue that needs to be addressed. Proper selection of suitable WWs is necessary before proceeding with large-scale FO-RO desalination plants. In this study, long-term experiments were carried out, using state-of-the-art FO membrane, using real WW and SW solutions. A combination of water flux modelling and membrane characterisation were used to assess the degree of membrane fouling and the impact on the process performance. Initial water flux as high as 22.5 Lm−2 h−1 was observed when using secondary effluent. It was also found that secondary effluent causes negligible flux decline. On the other hand, biologically treated wastewater and primary effluent caused mild and severe flux decline respectively (25% and 50% of flux decline after 80 hours, compared to no-fouling conditions). Ammonia leakage to the diluted seawater was also measured, concluding that, if biologically treated wastewater is used as feed, the final NH4+ concentration in the draw is likely to be negligible.
Chekli, L, Kim, JE, El Saliby, I, Kim, Y, Phuntsho, S, Li, S, Ghaffour, N, Leiknes, TO & Kyong Shon, H 2017, 'Fertilizer drawn forward osmosis process for sustainable water reuse to grow hydroponic lettuce using commercial nutrient solution', Separation and Purification Technology, vol. 181, pp. 18-28.View/Download from: UTS OPUS or Publisher's site
© 2017 Elsevier B.V. This study investigated the sustainable reuse of wastewater using fertilizer drawn forward osmosis (FDFO) process through osmotic dilution of commercial nutrient solution for hydroponics, a widely used technique for growing plants without soil. Results from the bench-scale experiments showed that the commercial hydroponic nutrient solution (i.e. solution containing water and essential nutrients) exhibited similar performance (i.e., water flux and reverse salt flux) to other inorganic draw solutions when treating synthetic wastewater. The use of hydroponic solution is highly advantageous since it provides all the required macro- (i.e., N, P and K) and micronutrients (i.e., Ca, Mg, S, Mn, B, Zn and Mo) in a single balanced solution and can therefore be used directly after dilution without the need to add any elements. After long-term operation (i.e. up to 75% water recovery), different physical cleaning methods were tested and results showed that hydraulic flushing can effectively restore up to 75% of the initial water flux while osmotic backwashing was able to restore the initial water flux by more than 95%; illustrating the low-fouling potential of the FDFO process. Pilot-scale studies demonstrated that the FDFO process is able to produce the required nutrient concentration and final water quality (i.e., pH and conductivity) suitable for hydroponic applications. Coupling FDFO with pressure assisted osmosis (PAO) in the later stages could help in saving operational costs (i.e., energy and membrane replacement costs). Finally, the test application of nutrient solution produced by the pilot FDFO process to hydroponic lettuce showed similar growth pattern as the control without any signs of nutrient deficiency.
Kim, J, Blandin, G, Phuntsho, S, Verliefde, A, Le-Clech, P & Shon, H 2017, 'Practical considerations for operability of an 8″ spiral wound forward osmosis module: Hydrodynamics, fouling behaviour and cleaning strategy', Desalination, vol. 404, pp. 249-258.View/Download from: UTS OPUS or Publisher's site
A better understanding of large spiral wound forward osmosis (SW FO) module operation is needed to provide practical insight for a full-scale FO practical implementation desalination plant. Therefore, this study investigated two different 8″ SW FO modules (i.e. cellulose tri acetate, CTA and thin film composite, TFC) in terms of hydrodynamics, operating pressure, water and solute fluxes, fouling behaviour and cleaning strategy. For both modules, a significantly lower flow rate was required in the draw channel than in the feed channel due to important pressure-drop in the draw channel and was a particularly critical operating challenge in the CTA module when permeate spacers are used. Under FO and pressure assisted osmosis (PAO, up to 2.5ï¿½bar) operations, the TFC module featured higher water flux and lower reverse salt flux than the CTA module. For both modules, fouling tests demonstrated that feed inlet pressure was more sensitive to foulant deposition than the flux, thus confirming that FO fouling deposition occurs in the feed channel rather than on the membrane surface. Osmotic backwash combined with physical cleaning used in this study confirmed to be effective and adapted to large-scale FO module operation.
Kim, JE, Phuntsho, S, Chekli, L, Hong, S, Ghaffour, N, Leiknes, TO, Choi, JY & Shon, HK 2017, 'Environmental and economic impacts of fertilizer drawn forward osmosis and nanofiltration hybrid system', Desalination, vol. 416, pp. 76-85.View/Download from: UTS OPUS or Publisher's site
© 2017 Environmental and economic impacts of the fertilizer drawn forward osmosis (FDFO) and nanofiltration (NF) hybrid system were conducted and compared with conventional reverse osmosis (RO) hybrid scenarios using microfiltration (MF) or ultrafiltration (UF) as a pre-treatment process. The results showed that the FDFO-NF hybrid system using thin film composite forward osmosis (TFC) FO membrane has less environmental impact than conventional RO hybrid systems due to lower consumption of energy and cleaning chemicals. The energy requirement for the treatment of mine impaired water by the FDFO-NF hybrid system was 1.08 kWh/m 3 , which is 13.6% less energy than an MF-RO and 21% less than UF-RO under similar initial feed solution. In a closed-loop system, the FDFO-NF hybrid system using a TFC FO membrane with an optimum NF recovery rate of 84% had the lowest unit operating expenditure of AUD $0.41/m 3 . Besides, given the current relatively high price and low flux performance of the cellulose triacetate and TFC FO membranes, the FDFO-NF hybrid system still holds opportunities to reduce operating expenditure further. Optimizing NF recovery rates and improving the water flux of the membrane would decrease the unit OPEX costs, although the TFC FO membrane would be less sensitive to this effect.
Kook, S, Kim, J, Kim, SJ, Lee, J, Han, D, Phuntsho, S, Shim, WG, Hwang, M, Shon, HK & Kim, IS 2017, 'Effect of initial feed and draw flowrates on performance of an 8040 spiral-wound forward osmosis membrane element', Desalination and Water Treatment, vol. 72, pp. 1-12.View/Download from: UTS OPUS or Publisher's site
© 2017, Desalination Publications. All rights reserved. This study investigated the effects of initial feed (20–50 L/min) and draw flowrates (2–5 L/min) on 8040 spiral-wound FO element performances in serial configuration for a forward osmosis and reverse osmosis (FO-RO) hybrid system employing single element-based tests. Average J w,ave values for varying feed and draw flowrates were found to be 20.93, 19.38 and 18.71 LMH at E1, E2 and E3 (first, second and third elements in a serial configuration), respectively, with averaged diluted draw concentrations of 12.55, 7.88 and 5.77 g/L (initial conc. = 35 g/L). The draw stream dilution was not governed by J w,ave but by the initial draw flowrates at the inlet that governs the retention time of the draw water body in the element. To sum up the performance results, it was concluded that initial draw flowrate is found to govern the performances of FO elements in series in terms of both production of diluted draw stream, determined by the averaged water flux of the FO element, J w,ave , and the degree of draw stream dilution. Specific energy consumptions (SECs) of RO were estimated with varying RO feed concentrations (i.e. diluted draw concentration); it was observed the efficiency of SEC reduction by the dilution significantly decays after a critical RO recovery rate. This study successfully provides a valuable insight for feasible application of the FO-RO hybrid system.
Phuntsho, S, Kim, JE, Hong, S, Ghaffour, N, Leiknes, TO, Choi, JY & Shon, HK 2017, 'A closed-loop forward osmosis-nanofiltration hybrid system: Understanding process implications through full-scale simulation', Desalination, vol. 421, pp. 169-178.View/Download from: UTS OPUS or Publisher's site
© 2016 Elsevier B.V.This study presents simulation of a closed-loop forward osmosis (FO)-nanofiltration (NF) hybrid system using fertiliser draw solution (DS) based on thermodynamic mass balance in a full-scale system neglecting the non-idealities such as finite membrane area that may exist in a real process. The simulation shows that the DS input parameters such as initial concentrations and its flow rates cannot be arbitrarily selected for a plant with defined volume output. For a fixed FO-NF plant capacity and feed concentration, the required initial DS flow rate varies inversely with the initial DS concentration or vice-versa. The net DS mass flow rate, a parameter constant for a fixed plant capacity but that increases linearly with the plant capacity and feed concentration, is the most important operational parameter of a closed-loop system. Increasing either of them or both increases the mass flow rate to the system directly affecting the final concentration of the diluted DS with direct energy implications to the NF process. Besides, the initial DS concentration and flow rates are also limited by the optimum recovery rates at which NF process can be operated which otherwise also have direct implications to the NF energy. This simulation also presents quantitative analysis of the reverse diffusion of fertiliser nutrients towards feed brine and the gradual accumulation of feed solutes within the closed system.
Chekli, LM, Phuntsho, S, Kim, JE, Kim, JH, Choi, JY, Choi, JS, Kim, SH, Kim, JH, Hong, SK, Sohn, JS & Shon, HK 2016, 'A comprehensive review of hybrid forward osmosis systems: Performance, applications and future prospects', Journal of Membrane Science, vol. 497, no. 1, pp. 430-449.View/Download from: UTS OPUS or Publisher's site
Forward osmosis (FO) has been increasingly studied in the past decade for its potential as an emerging low-energy water and wastewater treatment process. However, the term “low-energy” may only be suitable for those applications in where no further treatment of the draw solution (DS) is required either in the form of pretreatment or post-treatment to the FO process (e.g. where the diluted DS is the targeted final product which can be used directly or simply discarded). In most applications, FO has to be coupled with another separation process in a so-called hybrid FO system to either separate the DS from the final product water or to be used as an advanced pre-treatment process to conventional desalination technologies. The additional process increases the capital cost as well as the energy demand of the overall system which is one of the several challenges that hybrid FO systems need to overcome to compete with other separation technologies. Yet, there are some applications where hybrid FO systems can outperform conventional processes and this study aims to provide a comprehensive review on the current state of hybrid FO systems. The recent development and performance of hybrid FO systems in different applications have been reported. This review also highlights the future research directions for the current hybrid FO systems to achieve successful implementation.
Phuntsho, S, Kim, JE, Johir, MAH, Hong, S, Li, Z, Ghaffour, N, Leiknes, T & Shon, HK 2016, 'Fertiliser drawn forward osmosis process: Pilot-scale desalination of mine impaired water for fertigation', JOURNAL OF MEMBRANE SCIENCE, vol. 508, pp. 22-31.View/Download from: UTS OPUS or Publisher's site
Majeed, T, Sahebi, S, Lotfi, F, Kim, JE, Phuntsho, S, Tijing, LD & Shon, HK 2015, 'Fertilizer-drawn forward osmosis for irrigation of tomatoes', Desalination and Water Treatment, vol. 53, no. 10, pp. 2746-2759.View/Download from: UTS OPUS or Publisher's site
Kim, J, Jeong, K, Park, MJ, Shon, HK & Kim, JH 2015, 'Recent Advances in Osmotic Energy Generation via Pressure-Retarded Osmosis (PRO): A Review', ENERGIES, vol. 8, no. 10, pp. 11821-11845.View/Download from: UTS OPUS or Publisher's site
Kim, J, Phuntsho, S, Lotfi, F & Shon, H 2015, 'Investigation of pilot-scale 8040 FO membrane module under different operating conditions for brackish water desalination', Desalination and Water Treatment, vol. 53, no. 10, pp. 2782-2791.View/Download from: UTS OPUS or Publisher's site
Two spiral wound forward osmosis membrane modules with different spacer designs (corrugated spacer [CS] and medium spacer [MS]) were investigated for the fertilizer-drawn forward osmosis (FO) desalination of brackish groundwater (BGW) at a pilot-scale level. This study mainly focused on examining the influence of various operating conditions such as feed flow rate, total dissolved solids (TDS) concentration of the BGW feed, and draw solution (DS) concentrations using ammonium sulfate ((NH4)2SO4, SOA) on the performance of two membrane modules. The feed flow rate played a positive role in the average water flux of the pilot-scale FO membrane module due to enhanced mass transfer coefficient across the membrane surface. Feed TDS and DS concentrations also played a significant role in both FO membrane modules because they are directly related to the osmotic driving force and membrane fouling tendency. CS module performed slightly better than MS module during all experiments due to probably enhanced mass transfer and lower fouling propensity associated with the CS. Besides, CS spacer provides larger channel space that can accommodate larger volumes of DS, and hence, could maintain higher DS concentration. However, the extent of dilution for the CS module is slightly lower.
Majeed, T, Phuntsho, S, Sahebi, S, Kim, J, Yoon, JK, Kim, K & Shon, H 2015, 'Influence of the process parameters on hollow fiber forward osmosis membrane performances', Desalination and Water Treatment, vol. 54, no. 4-5, pp. 817-828.View/Download from: UTS OPUS or Publisher's site
Continued efforts are made in improving the performance of the low-cost forward osmosis (FO) membrane process which utilizes naturally available osmotic pressure of the draw solution (DS) as the driving force. Selection of a suitable DS and development of a better performing membrane remained the main research focus. In this study, the performance of a hollow fiber forward osmosis (HFFO) membrane was evaluated with respect to various operating conditions such as different cross-flow directions, membrane orientation, solution properties, and solution flow rates (Reynolds number). The study observed that operating parameters significantly affect the performance of the FO process. FO comparatively showed better performance at counter-current orientation. NaCl, KCl, and NH4Cl were evaluated as DS carrying common anion. Properties of the anionic part of the DS were found important for flux outcome, whereas reverse solute flux (RSF) was largely influenced by the properties of DS cationic part. FO was operated at different DS and feed solution (FS) flow rates and FO outcome was assessed for varying DS and FS Reynolds number ratio. FO showed better flux outcome as Re ratio for DS and FS decreases and vice versa. Results indicated that by adjusting FO processes conditions, HFFO membrane could achieve significantly lower specific RSF and higher water flux outcome. It was observed that using 2 M NaCl as DS and deionized water as FS, HFFO successfully delivered flux of 62.9 LMH which is significantly high compared to many FO membranes reported in the literature under the active layer-DS membrane orientation mode.
Sahebi, S, Phuntsho, S, Kim, JE, Hong, S & Shon, HK 2015, 'Pressure assisted fertiliser drawn osmosis process to enhance final dilution of the fertiliser draw solution beyond osmotic equilibrium', JOURNAL OF MEMBRANE SCIENCE, vol. 481, pp. 63-72.View/Download from: UTS OPUS or Publisher's site
Kim, J, Phuntsho, S & Shon, H 2013, 'Pilot-scale nanofiltration system as post-treatment for fertilizer drawn forward osmosis desalination for direct fertigation', Desalination and Water Treatment, vol. 51, no. 31-33, pp. 6265-6273.View/Download from: UTS OPUS or Publisher's site
The integration of the fertilizer-drawn forward osmosis with nanofiltration (NF) has been investigated to evaluate the performance of NF process as a post-treatment. The primary objective of this study is to optimize the operating conditions such as feed flow rate and feed concentration, while producing fresh water including low nutrient (N) concentration can be directly used for irrigation. Investigation of operating parameters at the pilot-scale level focused on specific water flux and ammonium sulphate rejection. Results from this study showed that NF process applied as the post-treatment can effectively reject the N concentration more than 90%. Although other factors such as the applied pressure and the cross-flow rates played a certain role in the performance of the pilot-scale NF process, the influence of the feed concentration was more significant on the specific water flux and N rejection.
Chekli, LM, Shon, HK, Phuntsho, S, Kim, J & Cho, J 2015, 'Draw Solutes in Forward Osmosis Processes' in Shon, HK, Phuntsho & Zhang, T (eds), Forward Osmosis: Fundamentals and Applications, American Society of Civil Engineers, USA, pp. 85-113.View/Download from: UTS OPUS or Publisher's site
This chapter provides insight into the selection of suitable draw solutions (DS) and reviews different DS characteristics affecting the performance of forward osmosis (FO) processes. Although some commercial applications of FO technology exist, the development of an effective large-scale process is currently limited due to the lack of both suitable DS and membrane. The success of most FO applications also relies on how the DS can be recovered from the produced water. Therefore, in commercial FO processes, such as FO followed by reverse osmosis seawater desalination, emergency drinks and osmotic dilution are used without a DS recovery system—a simple and energy-saving solution. Research is still needed to develop more suitable DS to achieve full-scale commercialization of the FO process.
Phuntsho, S, Kim, J, Majeed, T, Lotfi, F, Sahebi, S, Park, S & Shon, HK 2015, 'Fertiliser-Drawn Forward Osmosis Desalination for Fertigation' in Shon, HK, Phuntsho, S, Zhang, TC & Surampalli, RY (eds), Forward Osmosis: Fundamentals and Applications, American Society of Civil Engineers, Reston, Virginia, USA, pp. 395-426.View/Download from: UTS OPUS or Publisher's site
This chapter explains the concept of the fertilizer-drawn forward osmosis (FDFO) desalination process and evaluates the potential of fertilizer solutions as draw solutions (DS). Different types of fertilizers are used to grow crops, and hence understanding what types of fertilizers are more suitable for the FDFO desalination process and how to screen and assess suitable fertilizer candidates for use as DS in the FDFO desalination process is important. FDFO desalination adds value to irrigation water and provides more opportunities for improving the efficiencies of water and fertilizer use. The major limitations of the FDFO desalination process are the challenge of meeting the irrigation water quality standards in terms of nutrient concentrations, which limits the direct use of FDFO product water for fertigation. Several options are discussed that could be integrated with the FDFO desalination process to reduce the final nutrient concentration closer to an acceptable limit.
Kim, J, Phuntsho, S, Chekli, L & Shon, H 2016, 'Environmental and economic assessment of fertilizer drawn forward osmosis and nanofiltration hybrid system for desalination of mine impaired water for irrigation', 26th Annual Meeting of the North American Membrane Society, NAMS 2016, pp. 13-14.