Fertilizer-drawn Forward Osmosis Research Articles

Evaluation of a novel fertilizer-drawn forward osmosis and membrane contactor hybrid system for CO2 capture using ammonia-rich wastewater

Chemical absorption is widely employed to capture carbon dioxide (CO2) for addressing climate change. While monoethanolamine (MEA) currently dominates as an absorption solvent, utilizing ammonia-rich wastewater offers advantages such as reduced costs, high absorption capacity, and the generation of ammonium carbamate. This study proposes an innovative fertilizer-drawn forward osmosis (FDFO)-membrane contactor (MC) hybrid system for economically and sustainably mitigating CO2 emissions using ammonia-rich wastewater. First, ammonia-lean synthetic wastewater was concentrated through an FDFO system, using three fertilizers (KCl, monoammonium phosphate, and diammonium phosphate) as draw solutions. While KCl achieved a 45% ammonia dilution, diammonium phosphate yielded the highest concentration approximately 49%. Also, MCs were assessed for CO2 absorption under various operational conditions. Increased liquid concentration and flow rates improved CO2 capture efficiency, whereas higher CO2 flow rates and concentrations resulted in an adverse effect. Furthermore, a simulation study of a hybrid FDFO-MC system was conducted to evaluate the feasibility and potential of the system. The results indicated that the FDFO-MC hybrid system has the potential to efficiently remove CO2 if sufficient concentration and flow rate of ammonia-rich solution was secured at the FDFO outlet. This innovation addresses CO2 emissions and wastewater challenges, adhering to circular economy principles.

Fabricated magnetic adsorption – Forward osmosis membrane hybrid system for hydroponic irrigation from rich arsenic–containing heavy metal water stream

Solidification of soluble arsenic from extremely acidic water and direct use of recovery water have been the major challenges in global water management, with the urgent need for new treatment system development. Thus, magnetic adsorption – fertilizer drawn forward osmosis (FDFO) hybrid system with a novel adsorbent and fertilizer mixture to solve the drawbacks of each process was developed with the ultimate goals of metal removal and direct reuse for hydroponic irrigation. Magnetic metal-organic framework-based adsorbent (CMM) was synthesized with various promising capabilities, i.e., wide pH range efficiency, strong pH adjustment, good stability, fast adsorption (1 h), and oxidation (40 min), high capacity (175 and 126 mg/g for As(III), As(V)), strong magnetization (75 emu/g), complete separation by a magnet, excellent interference-tolerance and reusability. In the FDFO system, a massive water volume (50 times higher than the initial draw solution with suitable nutrients for hydroponics irrigation with acceptable NaCl levels was obtained for the first time up to now. However, low As(III) rejection (50%) required the FDFO process to improve more. After integrating with magnetic adsorption, nearly 100% of As was removed. The pH of feed solutions adjusted from extremely acidic to close to neutral conditions further solidified metal by precipitation and membrane separation processes, leading to almost no detection of metals in the final draw solution. Also, favorable nutrients and excellent reusability were obtained. This hybrid process would generally offer an environmentally sustainable and high efficiency for decontaminating As-containing heavy metal water for hydroponic irrigation.

Towards enhanced performance of fertilizer-drawn forward osmosis process coupled with sludge thickening using a thin-film nanocomposite membrane interlayered with Mxene scaffolded alginate hydrogel

Forward osmosis (FO) offers the potential for sustainable wastewater reuse and enhance water resource sustainability and resiliency. However, low performance of FO membranes due to the high structural parameter and poor fouling resistance limits their widespread implementation. Structural parameter minimization of substrates and modulation of the surface structures of polyamide nanofilms are crucial to achieve enhanced FO performance. Herein, a novel thin-film nanocomposite (TFN) FO membrane supported with Mxene scaffolded alginate hydrogel interlayer is fabricated. It is found that the incorporation of the hydrophilic and high surface energy alginate hydrogel@Mxene interlayer sandwiched between polyamide nanofilms and microporous substrate minimizes the structural parameter by creating abundant tortuous paths leading to minimized internal concentration polarization. Meanwhile, the nanoconfinement effect induced by the interlayer enabled the formation of lumpy network of bubble wrap-like textured polyamide structures on the membranes. Subsequently, the resulting membranes exhibited enhanced water flux of up to 45.6 LMH in PRO mode using 1.0 M NaCl as the draw solution, while the lower surface roughness bestowed the membranes with the minimal fouling propensity which resulted in more than 80% of the water recovery. Additionally, the integration of the fertilizer-drawn forward osmosis process with sludge thickening successfully enabled the dilution of a 2 M KCl fertilizer solution by 2.4 times after 12 h operation, while simultaneously concentrating the sludge from the MLSS of 2000 mg L−1 to 5183 mg L−1. This work provides important insightful concepts to inspire the development of advanced TFN-FO membranes with good overall performance suitable for sustainable water reuse using osmotically driven membrane processes.

Effects of feed solution chemistry on membrane scaling in fertilizer-drawn forward osmosis process for sustainable agricultural reuse

Scaling formation on the forward osmosis (FO) membrane surface is a critical problem in fertilizer-drawn forward osmosis (FDFO). In this study, the effect of feed solution chemistry on scaling formation in the FDFO process was investigated. The results revealed that the flux decline ratio (FDR) increased with the pH of the feed solution owing to the acceleration of reverse salt flux (RSF) diffusion. FDR decreased as the temperature of the feed solution increased. Higher temperatures in the feed solution hinder membrane scaling by interrupting the RSF from the draw to the feed solution. Calcium has higher reactivity than magnesium, and it has a higher potential for forming scales on the membrane surface than magnesium in the FDFO process. The flux was not fully recovered by physical cleaning, but 87 % of the water flux was recovered using chemical cleaning using an acid solution (HCl). This study provides information on membrane scaling in the FDFO process for wastewater treatment applications.

Novel organic draw solution in forward osmosis process for fertigation: performance evaluation and flux prediction

Fertilizer-drawn forward osmosis (FDFO) has received a lot of attention for its potential for producing fertigated water for agriculture purposes. To minimize the use of chemical-based fertilizers and support sustainable organic agriculture, this work investigated the separation performance of FO membrane for different feed concentrations (FS) of brackish water using microalgae Spirulina platensis as an organic fertilizer draw solution (DS). Different feed solution concentrations were investigated ranging 3–20 g/L NaCl, with various draw solutions of spirulina ranging 280–440 g/L. The performance was measured by water flux and recovery. The results showed that using spirulina as a draw solution is a promising solution for fertigation purposes. The results showed that Na+ in feed solution is concentrated by 41%, Cl- by 36%, and spirulina is diluted by 20% for feed salinity 5000 mg/L. The highest flux obtained with different feed solution 3000/5000/10,000/20,000 mg/L were 9/6/4.5/7 for draw solution concentration of 360/360/400/420 g/L. The calculated specific reverse solute flux (SRSF) JS/JW varies from 0.1 and 0.8 for different explored FS/DS concentrations. Flux decline and the down-time was investigated for the highest flux observed, showing 290 min of operation before cleaning action is required.

Investigating the performance of hydroponic nutrient solutions as potential draw solutions for fertilizer drawn forward osmosis.

This research project aims at investigating the performance of hydroponic nutrient solutions as draw solutions for desalination using the fertilizer drawn forward osmosis (FDFO) process. Six different lettuce and leafy greens hydroponic nutrient stock solutions were prepared according to the literature and used in this study and tested on a bench-scale forward osmosis unit as draw solutions for the process. The feed solution for the process was deionized water mixed with NaCl in different concentrations, to represent different salinities of brackish groundwater. The draw efficiency of each solution was measured based on water flux, specific reverse solute flux, water recovery, and salt rejection. It was concluded that of the six tested nutrient solutions, the "Resh Florida, California" solution is the recommended solution to be used as draw solution for fertilizer drawn forward osmosis, due to its high performance in terms of water recovery (15.75%), flux (11 L/m2/h), salt rejection (92%), and SRSF (highest recorded SRSF for a specific ion (SO42-) was 7.3g/L), as well as its low cost, relative to the other highly performing draw solution "Chekli" ($1.07/L vs. $3.73/L).

Effects of Feed Solution Chemistry on Membrane Scaling in Fertilizer-Drawn Forward Osmosis Process

Effects of Feed Solution Chemistry on Membrane Scaling in Fertilizer-Drawn Forward Osmosis Process

Exploring the limitations of forward osmosis for direct hydroponic fertigation: Impact of ion transfer and fertilizer composition on effective dilution

There is a need for water reuse technologies and applications to minimize the imminent water crisis, caused by the world population growth, the reduction of freshwater resources and the increasing water pollution. Fertilizer-drawn forward osmosis (FDFO) is a promising process capable of simultaneously extracting fresh water from low-quality sources as feed water (e.g., wastewater or greywater), while diluting fertilizer solutions for direct fertigation, avoiding the demand for freshwater for irrigation. Achieving an adequate level of dilution for direct fertigation is a key element to be evaluated for the implementation of FDFO. This study assessed the performance of the forward osmosis process to dilute fertilizer solutions to be applied directly in hydroponic systems. Experiments were carried out under conditions close to osmotic equilibrium to evaluate the process performance up to the maximum dilution point. Tests were carried out with individual and blended fertilizers (i.e., (NH4)2HPO4 or DAP, and KNO3) used as draw solution (DS) and with deionized water or individual salts (NaCl, MgCl2, Na2SO4, MgSO4) in the feed solution (FS). Water fluxes and reverse salt fluxes indicated that both fertilizer DS composition and concentrations play a fundamental role in the process. Suitable nutrient concentrations to be directly applied without further dilution for N, P and K (119, 40, 264 mg.L−1 respectively) were obtained with deionized water as FS and blended DAP (0.025 M) and KNO3 (0.15 M) as DS. However, important fertilizer losses from DS to FS were observed, being the highest for NO3− (33–70% losses from DS to FS). The presence of salts in FS decreased the water fluxes and the DS dilution due to the osmotic equilibrium caused by a greater loss of nutrients from DS to FS (up to 100%), compared with tests using just deionized water as FS. This study points out the potential limitations of the FDFO process, due to the high solute fluxes and low water fluxes in conditions close to osmotic equilibrium.

Inorganic scaling in the treatment of shale gas wastewater by fertilizer drawn forward osmosis process

In this study, fertilizer drawn forward osmosis (FDFO) process was applied for the treatment of shale gas wastewater. The forward osmosis (FO) experiments with simulated shale gas wastewater and real shale gas wastewater were carried out, respectively. The effects of reverse salt diffusion on the inorganic fouling to the membrane surface was systematically investigated. Two commercial FO membranes were selected and the optimized operating conditions were evaluated. It was found that calcium sulfate scaling can be alleviated by optimizing the operating parameters, including increasing flow rate and decreasing temperature. Furthermore, the Aquaporin FO membrane, which has lower reverse salt flux and less surface charge potential, exhibited lower fouling tendency. Under the optimal operating conditions, the effects of reverse salt diffusion on the barium sulfate scaling were also analyzed. The presence of calcium ions can alleviate barium sulfate scaling, while sodium chloride will aggravate the barium sulfate scaling. In addition, the scaling behavior of real shale gas wastewater was further explored. Inorganic scaling phenomenon seriously affected the FO membrane performance and lower pH had beneficial effect on recycling the real shale gas wastewater. The present study provided both theoretical fundamentals and industry applicable practices for implementing FO technology in the treatment and resource recovery of shale gas wastewater.

Evaluating Fertilizer-Drawn Forward Osmosis Performance in Treating Anaerobic Palm Oil Mill Effluent.

Fertilizer-drawn forward osmosis (FDFO) is a potential alternative to recover and reuse water and nutrients from agricultural wastewater, such as palm oil mill effluent that consists of 95% water and is rich in nutrients. This study investigated the potential of commercial fertilizers as draw solution (DS) in FDFO to treat anaerobic palm oil mill effluent (An-POME). The process parameters affecting FO were studied and optimized, which were then applied to fertilizer selection based on FO performance and fouling propensity. Six commonly used fertilizers were screened and assessed in terms of pure water flux (Jw) and reverse salt flux (JS). Ammonium sulfate ((NH4)2SO4), mono-ammonium phosphate (MAP), and potassium chloride (KCl) were further evaluated with An-POME. MAP showed the best performance against An-POME, with a high average water flux, low flux decline, the highest performance ratio (PR), and highest water recovery of 5.9% for a 4-h operation. In a 24-h fouling run, the average flux decline and water recovered were 84% and 15%, respectively. Both hydraulic flushing and osmotic backwashing cleaning were able to effectively restore the water flux. The results demonstrated that FDFO using commercial fertilizers has the potential for the treatment of An-POME for water recovery. Nevertheless, further investigation is needed to address challenges such as JS and the dilution factor of DS for direct use of fertigation.

Investigating sustainable management of desalination brine through concentration using forward osmosis

A fertilizer drawn forward osmosis (FDFO) process was tested for the concentration of synthetic brine using an industrial-grade fertilizer ammonium sulfate (NH4)2SO4 as the draw solution (DS), NaCl-based synthetic brine as the feed solution (FS), and a commercial forward osmosis (FO) membrane. A bench-scale investigation and a pilot-scale investigation were carried out. By using the highest possible concentration of the DS with a fixed concentration of the FS, the brine generated by reverse osmosis (RO) desalination plants was simulated. The aim of this investigation, performed in batch mode, was to assess the feasibility of using the FDFO process with the tested DS to concentrate the brine by extracting water to dilute the DS. While the main aim of the investigated process was achieving the maximum possible volume reduction of the brine, the resulting DS was further diluted to reduce the nutrients’ concentration in the diluted DS to the acceptable levels producing fertilized water that can be used for fertigation. The investigation showed that the proposed process using the tested fertilizer resulted in an average water flux of 8.01 l/h/m2, and a volume reduction of the brine of around 12%.

Effect of Membrane Fouling on Fertilizer-Drawn Forward Osmosis Desalination Performance.

Fertilizer-drawn forward osmosis (FDFO) has garnered immense attention for its application in the agricultural field and its potential to reuse wastewater sustainably. Membrane fouling, however, remains to be a challenge for the process. This study aims to investigate the influence of membrane fouling on the performance of the FDFO process. Synthetic wastewater (SWW) and multi-component fertilizer (MCF) were used as feed solution (FS) and draw solution (DS) with cellulose triacetate (CTA) forward osmosis (FO) membrane orientation. The performance was evaluated through water flux (WF), percentage recovery and percentage of salt reject. The WF declined from 10.32 LMH (L/m2·h) to 3.30 LMH when ultra-pure water as FS was switched with concentration FS indicating the dependence of the performance on the type of FS used. Accelerated fouling experiments conducted to verify the fouling behavior showed a decline in the water flux from 8.6 LMH to 3.09 LMH with SWW and 13.1 LMH to 3.42 LMH when deionized water was used as FS. The effects of osmotic backwashing and in situ flushing as physical cleaning methods of the foul membrane were studied through water flux and salt recovery percentage. Both cleaning methods yielded a WF close to the baseline. Osmotic backwashing yielded better results by eliminating foulant–foulant and foulant–membrane adhesion. The cleaning methods were able to recover 75% of phosphate and 60% of nitrate salts. Scanning electron microscopy (SEM), atomic force microscopy (AFM) and Fourier transform infrared (FTIR) results validated the effectiveness of the methods for the physical cleaning of foul membranes. This study underlines the importance of the FS used in FDFO and the effectiveness of osmotic backwashing as a cleaning method of FO membranes.

On-Site Treatment of Shale Gas Flowback and Produced Water in Sichuan Basin by Fertilizer Drawn Forward Osmosis for Irrigation.

Fertilizer drawn forward osmosis (FDFO) was proposed to extract fresh water from flowback and produced water (FPW) from shale gas extraction for irrigation, with fertilizer types and membrane orientations assessed. The draw solution (DS) with NH4H2PO4 displayed the best performance, while the DS with (NH4)2HPO4 resulted in the most severe membrane fouling. The DS with KCl and KNO3 led to substantial reverse solute fluxes. The FDFO operation where the active layer of the membrane was facing the feed solution outperformed that when the active layer was facing the DS. The diluted DS and diluted FPW samples were used for irrigation of Cherry radish and Chinese cabbage. Compared to deionized water, irrigation with the diluted DS (total dissolved solid (TDS) = 350 mg·L-1) promoted plant growth. In contrast, inhibited plant growth was observed when FPW with high salinity (TDS = 5000 mg·L-1) and low salinity (TDS = 1000 mg·L-1) was used for irrigation of long-term (8-week) plant cultures. Finally, upregulated genes were identified to illustrate the difference in plant growth. The results of this study provide a guide for efficient and safe use of FPW after FDFO treatment for agricultural application.

Synergistic effect of amino-acids and metal salts as draw solutions to enhance the performance of fertilizer-drawn forward osmosis

Blended amino-acids–metal-salts were introduced as novel fertilizer draw solutions. The synergic effects resulted in higher water flux than the sum of their individual fluxes.

Sustainable fertilizer-drawn forward osmosis for the vegetable industry in reducing liquor from vegetable waste

ABSTRACT Forward osmosis has been widely used due to its advantages such as low energy consumption and low membrane fouling. Conventional treatment of vegetable industry wastes leaving the liquor an additional puzzle. The objective of this study is to evaluate the feasibility of reducing energy consumption by using forward osmotic membrane technology to concentrate vegetable liquor. In this research, the suitable draw solutes’ condition was investigated, results showed 1 M ammonium sulphate could reach 7.21 LMH water flux and it was chosen as the draw solution for concentrating vegetable liquor, then the long-term FO performance was compared with theoretical water flux showing that the difference of water flux decrease is caused by the organic matter. Further identification of the major foulant via a control variable method using simulated vegetable liquor leads to anthocyanins as the major foulant. This novel application of the fertilizer drawn FO process provided an environmentally friendly solution to the vegetable industry, which would potentially transform an industry into a sustainable cyclic economy.

Understanding the organic micropollutants transport mechanisms in the fertilizer-drawn forward osmosis process

We systematically investigated the transport mechanisms of organic micropollutants (OMPs) in a fertilizer-drawn forward osmosis (FDFO) membrane process. Four representative OMPs, i.e., atenolol, atrazine, primidone, and caffeine, were chosen for their different molecular weights and structural characteristics. All the FDFO experiments were conducted with the membrane active layer on the feed solution (FS) side using three different fertilizer draw solutions (DS): potassium chloride (KCl), monoammonium phosphate (MAP), and diammonium phosphate (DAP) due to their different properties (i.e., osmotic pressure, diffusivity, viscosity and solution pH). Using KCl as the DS resulted in both the highest water flux and the highest reverse solute flux (RSF), while MAP and DAP resulted in similar water fluxes with varying RSF. The pH of the FS increased with DAP as the DS due to the reverse diffusion of NH4+ ions from the DS toward the FS, while for MAP and DAP DS, the pH of the FS was not impacted. The OMPs transport behavior (OMPs flux) was evaluated and compared with a simulated OMPs flux obtained via the pore-hindrance transport model to identify the effects of the OMPs structural properties. When MAP was used as DS, the OMPs flux was dominantly influenced by the physicochemical properties (i.e., hydrophobicity and surface charge). Those OMPs with positive charge and more hydrophobic, exhibited higher forward OMP fluxes. With DAP as the DS, the more hydrated FO membrane (caused by increased pH) as well as the enhanced RSF hindered OMPs transport through the FO membrane. With KCl as DS, the structural properties of the OMPs were dominant factors in the OMPs flux, however the higher RSF of the KCl draw solute may likely hamper the OMPs transport through the membrane especially those with higher MW (e.g., atenolol). The pore-hindrance model can be instrumental in understanding the effects of the hydrodynamic properties and the surface properties on the OMPs transport behaviors.

Performance and energy consumption evaluation of a fertiliser drawn forward osmosis (FDFO) system for water recovery from brackish water

Agriculture consumes approximately 70% of total freshwater worldwide. With limited freshwater resources, alternative water resources are required. This study investigated the performance of a fertiliser drawn forward osmosis (FDFO) system for water recovery from synthetic brackish water with repeated use of a cellulose triacetate (CTA) FO membrane under varying fertiliser draw solution (DS) concentrations (0.5, 1 and 2 M KCl); membrane orientations (FO vs PRO) and flow rates (100, 200 and 400 mL/min); with the corresponding effects on the specific energy consumption (SEC). Results demonstrated a robust CTA membrane with no damage. An increased DS concentration from 0.5 to 1 M KCl contributed to a three-fold increase in flux, followed by a 30 to 50% increase for 2 M KCl and a reduced SEC. Membrane orientation and flow rate had insignificant effects on performance, however, flow rate contributed to an SEC increase. FO mode at a lower flow rate combined with a higher DS concentration produced the lowest possible SEC. The study illustrated a potential lower energy process for water recovery from synthetic brackish water whilst at the same time producing a diluted fertiliser that could potentially be used for fertigation.

Brackish water desalination for agriculture: Assessing the performance of inorganic fertilizer draw solutions

Fertilizer drawn forward osmosis (FDFO) is a cost-effective technology for brackish water desalination. The diluted fertilizer draw solution can be used to supply nutrients to crops instead of separating it from the desalinated water. This work evaluates the performance of the FDFO using four fertilizer draw solutions with various concentrations (1.0, 1.5, 2.0 mol/L) and a polyamide thin film composite (TFC) FO membrane for brackish water desalination. The results revealed that KCl fertilizer draw solution achieved the highest water flux and adequate reverse salt flux as compared to other fertilizer draw solution. The mixture KCl + KNO3 and KH2PO4 fertilizer draw solution generated the lowest water permeation and reverse salt flux. KH2PO4 draw solute promoted the growth of salt scaling which affected the membrane productivity in terms of water flux. The negatively charge of the membrane surface was responsible for precipitation of salt on the selective layer. This influenced the performance and resulted in low water permeation and minimum loss of nutrients in the fertilizer draw solution. The advantage of FDFO is in not needing a recovery step to reconcentrate the draw solution, instead using diluted draw solution as a supplement to irrigation water via fertigation.

Impact of reverse nutrient diffusion on membrane biofouling in fertilizer-drawn forward osmosis

Biofouling in fertilizer-drawn forward osmosis (FDFO) for water reuse was investigated by spiking pure bacteria species Pseudomonas aeruginosa PAO1+GFP and using three different fertilizers KNO3, KCl and KH2PO4 as draw solutions. The performance of FO process for treating synthetic wastewater was assessed and their influence on the membrane fouling and in particular biofouling was evaluated relative to the type of different fertilizers used and their rates of reverse diffusion. FO performances using KNO3 as draw solute exhibited severer flux decline (63%) than when using KCl (45%) and KH2PO4 (30%). Membrane autopsy indicated that the mass of organic foulants and biomass on fouled membrane surface using KNO3 as draw solute (947.5mg/m2 biopolymers, 72µm biofilm thickness and 53.3mg/m2 adenosine triphosphate) were significantly higher than that using KCl (450mg/m2 biopolymers, 33µm biofilm thickness and 28.2mg/m2 ATP) and KH2PO4 (440mg/m2 biopolymers, 35µm biofilm thickness and 33.5mg/m2 ATP). This higher flux decline is likely related to the higher reverse diffusion of KNO3 (19.8g/m2/h) than KCl (5.1g/m2/h) and KH2PO4 (3.7g/m2/h). The reverse diffused potassium could promote the organics and bacterial adhesion on FO membrane via charge screening effect and compression of electrical double layer. Moreover, reverse diffused nitrate provided increased N:P nutrient ratio was favorable for the bacteria to grow on the feed side of the FO membrane.

Evaluation of fertilizer-drawn forward osmosis for coal seam gas reverse osmosis brine treatment and sustainable agricultural reuse

The fertilizer-drawn forward osmosis (FDFO) was investigated for treating coal seam gas (CSG) produced water to generate nutrient rich solution for irrigation. Its performance was evaluated and compared with reverse osmosis (RO) in terms of specific energy consumption (SEC) and nutrient concentrations in the final product water. The RO-FDFO hybrid process was developed to further improve FDFO. The results showed that FDFO has the lowest SEC followed by the RO-FDFO and RO processes. The final nutrient concentration simulation demonstrated that the RO-FDFO hybrid process has lower final concentration, higher maximum recovery and lower nutrient loss than the stand alone FDFO process. Therefore, it was suggested that the RO-FDFO is the most effective treatment option for CSG produced water as well as favourable nutrient supply. Lastly, membrane fouling mechanism was examined in CSG RO brine treatment by FDFO, and the strategies for controlling fouling were critically evaluated. KNO3 exhibited the highest flux decline corresponding to the highest reverse salt flux, while the most severe membrane scaling was observed with calcium nitrate, primarily due to the reverse transport of calcium ions. To control membrane fouling in FDFO process, both physical flushing and chemical cleaning were examined. Membrane cleaning with citric acid of 5% resulted in a complete flux recovery.