Reverse Osmosis Desalination Research Articles

An innovative optimal 4E solar-biomass waste polygeneration system for power, methanol, and freshwater production

Modern polygeneration systems have increased the flexibility of production in energy systems. In this paper, a polygeneration system for producing power, freshwater, and methanol using solar and waste resources is defined. By using waste heat recovery in Brayton, Steam Rankine, organic Rankine, and Kalina systems, power has been produced in the proposed system. Methanol is also provided by using CO2 capture from exhaust flue gases and hydrogen produced by Proton Exchange Membrane electrolyzer. The integration of microbial fuel cells, multi-effect distillation, and reverse osmosis desalination has been used for muddy seawater recovery and freshwater production. The proposed system has been analyzed using energy, exergy, exergeoeconomic, and exergoenvironmental (4E) analyses for three biomass fuels. The Multi-Objective Dragonfly Algorithm, Multi-Objective Thermal Exchange Optimization, Multi-objective Salp Swarm Algorithm, and Multi-Objective Water Cycle Algorithm have been used for the optimization of the whole system. In the end, the studied system has been modeled hourly. In this research, machine learning has been used to facilitate modeling the desalination sector, CO2 capture sector, and methanol production sector. Also, it has played a significant role in reducing optimization run time. The modeling results show that Municipal solid waste is the most economical fuel for the study system with a payback of 4.28 years. Date palm waste has also caused fewer environmental impacts than other fuels. The comparison of the results of optimization indicates that Multi-objective Salp Swarm Algorithm is the fastest method for system optimization and can lead to 4.04% and 7.16% improvement in the system cost and environmental impact rate. In general, the energy and exergy efficiencies of the system in the optimal state are calculated as 29.25%, and 23.59%, respectively. The total optimal production of electricity, methanol, and freshwater in the whole system is calculated at 62.86 MW, 1820.78 kg/h, and 63.88 kg/s, respectively. The dynamic analysis of the proposed system also showed that the production of methanol throughout the year will be higher using Municipal solid waste fuel than other fuels.

Wave energy potential analysis in the Kenitra-Atlantic coastal area (Morocco): First results

Waves generated by winds can transport a large amount of energy across the oceans with little loss. This paper explores the satellite-based data to assess the wave energy potential of Kenitra-Atlantic coastal area (Morocco), with an overall purpose of supporting the plans for developing and using wave energy, and provide guidance about the appropriate applications of wave energy of the Kenitra coastal area. Kenitra is important harbour and industrial city in Morocco. Various indexes, including the temporal distributions of wave parameters and wave energy fluxes, the occurrence of the effective significant wave height and wave energy flux, the variability and frequency of the wave status, were calculated from satellite measured weekly wave data, covering about 3 years (June 2019-November 2022) period. Results indicated that the area is characterized by moderate energy compared to South Africa, the most energetic site in the continent, with average wave significant wave of 1.6 ± 0.7, average wave period of 8.4 ± 2.4 s, average wave energy flux of 11.7 ± 14.0 kW m−1 and with the rate of variability of 28–45%. High energy above the threshold (> 10 kW m−1) for viable electricity production, applying turbines directly powered by waves, occurs only during the northern hemisphere winter (December–March). Hence, for off shore Kenitra, the study recommends other applications for wave energy other than electricity production through wave powered turbines, such as, reverse osmosis membrane-based electricity production technology, desalination, irrigation and water pumping for marine culture, mini-hydro and recreational. Subsequently, future studies may focus on the socio-economic viability of these wave energy applications and on developing other low energy demanding applications.

Solar energy utilization in desalination power plan

A steam power plant (PLTU) uses demin water to generate 3x350 MW of electrical energy. Reverse Osmosis Desalination system is used to treat the 190 m3/hour of desalinated water that is produced from seawater. Solar energy will replace the 225.41 kW of electrical energy required for the RO desalination pump in order to lessen pollution and the greenhouse effect caused by PLTU. The PLTU is situated in Pelabuhan Ratu Sukabumi, West Java. This region has a solar radiation potential of 3.189 kWp/day/m2 and a deployment space for PV modules of 6,167 m2, divided into two zones: the ground and the roof. The needs analysis is carried out by utilizing software simulations that estimate the power requirements of desalination pumps and the potential of electrical energy from solar radiation based on land availability. According to the modeling findings, PLTS can produce 1024 MWh/year of electrical energy with 1,458 pieces of 450 Wp PV modules and 5 units of 120 kW inverters.

Desalination Pretreatment Technologies: Current Status and Future Developments

Pretreatment of raw feed water is an essential step for proper functioning of a reverse osmosis (RO) desalination plant as it minimizes the risk of membrane fouling. Conventional pretreatment methods have drawbacks, such as the potential of biofouling, chemical consumption, and carryover. Non-conventional membrane-based pretreatment technologies have emerged as promising alternatives. The present review focuses on recent advances in MF, UF, and NF membrane pretreatment techniques that have been shown to be effective in preventing fouling as well as having low energy consumption. This review also highlights the advantages and disadvantages of polymeric and ceramic membranes. Hybrid technologies, which combine the benefits of conventional and non-conventional methods or different membranes, are also discussed as a potential solution for effective pretreatment. The literature that has been analyzed reveals the challenges associated with RO pretreatment, including the high cost of conventional pretreatment systems, the difficulty of controlling biofouling, and the production of large volumes of wastewater. To address these challenges, sustainable hybrid strategies for ceramic membrane-based systems in RO pretreatment are proposed. These strategies include a thorough assessment of the source water, removal of a wide range of impurities, and a combination of methods such as adsorption and carbon dioxide with a low amount of antiscalants. Furthermore, the suggestion of incorporating renewable energy sources such as solar or wind power can help reduce the environmental impact of the system. A pilot study is also recommended to overcome the difficulties in scaling ceramic systems from laboratory to industrial scale. The review also emphasizes the importance of conducting an effective assessment to suggest a treatment for the brine if needed before being discharged to the environment. By following this framework, sustainable, energy-efficient, and effective solutions can be recommended for pretreatment in desalination systems, which can have significant implications for water scarcity and environmental sustainability.

Calcium Sulfate Crystallization in Presence of Fluorecent-Tagged Polyacrylate and Some Refinement of Scale Inhibition Mechanism

Deposits of calcium sulfate scale on the surfaces of industrial equipment in distillation facilities, reverse osmosis desalination plants, in oil and gas industries lead to significant clogging of pipes and membranes and to a serious increase in production costs. For the mitigation of scale formation, the wide spectrum of antiscalants is applied. The present work is dedicated to the study of calcium sulfate deposition from supersaturated aqueous solutions in the presence of polyacrylic antiscalant with fluorescent marker (naphthalimide fragment) PAA-F1, which provides traceability of the scale inhibitor and a better understanding of its efficacy. A paradoxical phenomenon is being described here. Antiscalant causes a change in the crystal phase from bassanite to gypsum, significantly reduces the amount of deposit, but does not reveal the presence of its molecules either at the kink, step, or at selected edge sites of deposited crystals. Contrary to the predictions of the theory, it either stays in the aqueous phase, or forms its own separate phase Ca-PAA-F1. It is demonstrated that the antiscalant does not block the surfaces of calcium sulfate nuclei or crystal surfaces, but rather the foreign particles of nanodust with particle sizes around 1 nm, naturally occurring in any aqueous solution. As a result, the number of calcium nucleation sites is reduced, and the rate of scale formation decreases without any apparent antiscalant–scale interaction. On the grounds of the current experiment, the substoichiometric effect of scale inhibition obtained an alternative, quite stoichiometric explanation.

Thermo-Economic Assessment of Photovoltaic/Thermal Pan-Els-Powered Reverse Osmosis Desalination Unit Combined with Preheating Using Geothermal Energy

Recently, the reverse osmosis (RO) process is widely used in the field of desalinating brackish water and seawater to produce freshwater, but the disadvantage of using this technology is the increase in the rates of electrical energy consumption necessary to manage these units. To reduce the rates of electrical energy consumption in RO desalination plants, geothermal energy and photovoltaic/thermal panels were used as preheating units to heat the feed water before entering RO desalination plants. The proposed system in this study consists of an RO desalination plant with an energy recovery device, photovoltaic/thermal panels, and a geothermal energy extraction unit. To evaluate the system performance, three incorporated models were studied and validated by previous experimental data. The results indicated that incorporating the geothermal energy and photovoltaic/thermal panels with the RO desalination plants has positive effects in terms of increasing productivity and reducing the rates of specific power consumption in RO desalination plants. The average saving in the specific power consumption for utilizing the thermal recovery system of PV panels and geothermal energy as preheating units reached 29.1% and 40.75% for the treatment of seawater and brackish water, respectively. Additionally, the economic feasibility showed the saving in the cost of freshwater produced from the RO desalination plants for incorporating both geothermal energy and photovoltaic panels with a thermal recovery system with reverse osmosis desalination plants of up to 39.6%.

Trends and future outlooks in circularity of desalination membrane materials

Reverse osmosis desalination is one of the most important and increasingly popular technologies to augment available water resources. Central to the technology is a thin-film-composite polyamide membrane capable of separating pure water from seawater or brine. Since its conception and initiation, the membrane industry has followed a linear life-cycle scheme. However, increasing production costs of fossil-based materials and more stringent environmental regulations drive the initiatives to adapt to a circular economy of membrane materials. In this perspective, we briefly summarize the pressing issues in the state-of-the-art membrane industry, then discuss the opportunities in future technology innovations with a focus on sustainable membrane manufacturing and recycling, and lastly provided an outlook for future membrane design and fabrication towards a circular economy.

Metal organic frameworks (MOFs) for the removal of dissolved silica before reverse osmosis desalination

Freshwater scarcity in many arid regions necessitates brackish water desalination via reverse osmosis (RO). One of the key obstacles to lowering the cost of RO freshwater is scaling or fouling on the RO membrane caused by dissolved silica in the brackish water. Herein, a robust metal organic framework (MOF) material was produced with green production methods. During column tests, the MOF demonstrates a high and selective affinity toward silicic acid from the dominant species in brackish water (e.g., Cl-, SO42-, HCO3-, Ca2+, Mg2+). Further lab-scale desalination tests showed over 80% of the 10–15 µm sized stone-like scales on the membrane were reduced while a 28.1% increase in the permeate flux was observed compared to the RO membrane without MOF treatment. Plus, two regeneration methods based on the properties of the selected MOFs were developed and evaluated.

Economical study for hydrogen production from seawater using renewable energy in Egypt

AbstractThis study looks into the possibilities of hydrogen production in the north coast and red‐sea Zone, Egypt, to conver renewable energy to hydrogen (power to gas). The main purpose is to estimate the power needed for each kg of hydrogen production from seawater using renewable energy and then the quantity of desalinated seawater needed to cover this cost. We will discuss different scenarios; the main two scenarios are photovoltaic (PV) solar with reverse osmosis (RO) desalination and concentrating solar power (CSP) with multi‐effect desalination (MED).

Reduction of Energy Consumption of Brackish Water Reverse Osmosis Desalination System Via Model Based Optimisation

Reverse Osmosis (RO) process is being engaged to yield fresh water from brackish water sources. However, the RO process is characterized by its high specific energy consumption (SEC) owing to high-pressure pumps. The current study focuses on reducing the SEC of the brackish water RO desalination plant using model-based optimization practice. The inlet conditions of RO process such as the feed pressure, flow rate (individual membrane module and total plant) and temperature, have a substantial influence on the performance indicators namely, water productivity, product concentration and SEC. Therefore, the optimisation of this study has been directed to determine optimal inlet conditions within feasible limits to minimise SEC. Arab Potash Company (APC) brackish water RO desalination plant has been considered as the case study. The optimal inlet conditions have resulted in a significant energy saving of 27.97% depending on the set of decision variables being considered at a fixed brackish water feed concentration.

Selective lithium separation from desalination concentrates via the synergy of extractant mixtures

Seawater reverse osmosis (SWRO) desalination plants generate high volumes of concentrates, which contain, in addition to major salts, some elements of growing interest in minor concentrations. This is the case of lithium, highly demanded in the battery industry. In this work, the separation of Li+ from model SWRO brines has been evaluated by obtaining Li+ extraction curves with the combination of extractants DBM•TOPO and FDOD•TOPO, proving that both mixtures are capable of extracting Li+ under basic pH conditions, due to the keto-enolic tautomerism of the β-diketones. Li+ extraction values of 95.4 % for DBM•TOPO (pH = 12.2) and 100 % for FDOD•TOPO (pH = 9.0) were achieved. This behaviour was verified by the FT-IR analysis of the sample before and after the Li+ extraction. Finally, the selective separation of Li+ against other cations, such as Na+, K+, Mg2+, Ca2+ and Sr2+, present in the model brines at higher concentrations, was determined. Under mentioned experimental conditions, these cations are not extracted, reaching to Li+ selective separation close to 100 %. This study shows the first results on the selective extraction of lithium in complex SWRO brines, fostered through promising extractants mixtures showing a synergic effect towards Li+ in such multicomponent matrices.

Investigation of a reliable and sustainable stand-alone hybrid energy system for freshwater supply: a case study

ABSTRACT Hybrid renewable energy system-based reverse osmosis desalination has been identified as a reliable and sustainable solution for supplying potable water to the off-grid communities. In this respect, this study proposes a stand-alone hybrid energy system comprising solar PV, wind turbine, diesel generator, and a battery bank to power a reverse osmosis desalination plant. The proposed hybrid system is optimised using a novel metaheuristic optimisation technique named salp swarm algorithm (SSA) to minimise the three objective functions: levelised cost of energy (LCOE, $/kWh), life cycle emissions (LCE, CO2 kg-eq/yr.), and the excess energy (EE, kWh/yr.). Moreover, the performance of the novel algorithm is scrutinised using the benchmark solutions achieved from the widely utilised non-dominated sorting genetic algorithm II (NSGA-II) and particle swarm optimisation (PSO) techniques. In addition, the study also investigates the effects of water demand and the loss of power supply probability on the techno-economic performance. The results reveal that SSA outperforms NSGA-II and PSO algorithms towards achieving Pareto optimality hence provides financially rewarding solutions. The LCOE for the optimal HES is 0.179 $/kWh, and the LCE is 5921 CO2 kg-eq/yr. with an EE of 402 kWh/yr., whereas the cost of water for this system is 1.37 $/m3.

Pumping-Induced Feed Water Quality Variation and Its Impacts on the Sustainable Operation of a Brackish Water Reverse Osmosis Desalination Plant, City of Hialeah, Florida, USA

Brackish water reverse osmosis (BWRO) desalination of groundwater is believed to be a sustainable method of providing municipal utilities with a high-quality supply in regions where freshwater sources are stressed and not sustainable. A key aspect of water management is the ability to evaluate an aquifer containing brackish water to ascertain future pumping-induced water quality changes and their impacts on the facility operation and economics. The city of Hialeah, Florida, has operated a BWRO facility for the last 9 years. The facility has a maximum design capacity of about 88,000 m3/d but is currently operating at about 33,000 m3/d. The facility was designed to treat water with a TDS of up to 10,000 mg/L. A detailed hydrogeologic investigation, including groundwater solute-transport modeling, suggested that the salinity of the source water would remain under 10,000 mg/L of TDS during the 30-year life expectancy of the facility. However, after 9 years of operation, it was found that the rate of salinity increase was much higher than predicted (27.5%), at the low rate of 33,000 m3/d. If the faculty was operated at the maximum capacity, the ability of the plant to treat the source water might be between 5 and 10 years. The conceptual model used to guide the solute transport modeling was not accurate for this site because it did not incorporate the apparent enhanced leakance through the basal confining unit below the aquifer. The greater leakance was likely caused by undetected, irregularly distributed fracturing of the underlying confining dolostones. The facility will require a major redesign to upgrade the process to be able to treat seawater at a TDS significantly above 10,000 mg/L in the future, should that occur. While the change will be costly, with a high capital cost to change the process, increased energy consumption, and overall higher water treatment cost, it is still more sustainable and has less environmental impact compared to other alternatives (e.g., treating tidal sources of seawater). The use of electricity from nuclear or solar generation could mitigate the environmental impacts of higher power consumption.

Energy Efficiency Optimization in Onboard SWRO Desalination Plants Based on a Genetic Neuro-Fuzzy System

This work presents a novel intelligent control system based on a Genetic Neuro-Fuzzy tool to optimize and improve the performance of a seawater reverse osmosis desalination plant (SWRO) on board a marine vessel. This investigation pays special attention to minimizing energy consumption to improve the energy efficiency of this marine installation. The system analyzes measurements of different variables—seawater pH, seawater conductivity, permeate flow rate, permeate conductivity, and total energy consumed—in order to provide the most appropriate value of permeate flow rate control and operating pressure of the high-pressure pump (HPP). This intelligent method allows the plant to achieve output values nearer to the desired setpoints set by the plant operators.

Study on Cavitation of Port Plate of Seawater Desalination Pump with Energy Recovery Function

To address the problem of low integration and efficiency of reverse osmosis desalination system, an energy-recovery type incurve multiple acting pump is developed with integrated functions of a high-pressure pump, energy recovery device and booster pump. In order to determine its flow range and suppress cavitation generation, a mathematical model of the port plate is established, combining the realizable k-ɛ turbulence model and the Schnerr-Sauer cavitation model to obtain the internal flow field characteristics of the port plate. The effects of different rotational speeds and inlet pressures on cavitation were analyzed to obtain the gas volume fraction distribution rules. The design is based on the pressure and mass flow monitoring test device to verify the numerical calculation results. The results show that the experimental and simulation data match accurately, and with the increase in speed and the decrease in inlet pressure, the cavitation phenomenon becomes serious and the flow coefficient is reduced. The optimal working speed of the pump in this paper is 520 r/min and the output flow is 200 L/min. Compared with conventional products, the volume is reduced by more than 40%.

Numerical study on the energy consumption characteristics of a novel integrated pump-motor unit for SWRO desalination system

Energy recovery device (ERD) is a critical component in seawater reverse osmosis (SWRO) desalination systems, which recovers hydraulic energy from the high-pressure brine and effectively reduces system energy consumption. In this thesis, a novel integrated seawater desalination pump-motor energy recovery device (ISPM-ERD) without the slipper/swashplate interface is proposed to further reduce energy consumption and improve system integration, which is able of concomitantly achieving seawater pressurization and energy recovery. A co-simulation multibody dynamic model with rigid-flexible coupling is applied to precisely examine the internal power loss of ISPM-ERD, especially volumetric loss and mechanical loss of the key lubricating interface. Besides, the influence of shaft rotational speed and working pressure on the power loss and overall efficiency of ISPM-ERD are comparatively investigated. In addition, a performance study of the presented ISPM-ERD is carried out based on the co-simulation model, which reveals the energy recovery efficiency and specific energy consumption (SEC) of ISPM-ERD under various operating conditions. The results indicate that the proposed ISPM-ERD is sufficient to meet the needs of the small-scale SWRO systems, whose energy recovery efficiency is more than 90.1 % in the 3.0–7.0 MPa operating pressure range and the SEC of freshwater production is 2.94 kW·h/m3 under rated working conditions.

Novel high-throughput screening platform identifies enzymes to tackle biofouling on reverse osmosis membranes

Biofouling is a ubiquitous problem in many industrial systems including reverse osmosis (RO) desalination units where the biofilm impedes the water flow. It is essential to develop novel cleaning methods that are non-damaging and environmentally friendly. The most promising cleaning agents are enzymes, which can selectively cleave the components that stabilize the biofilm. However, biofilm-degrading enzymes are often difficult to identify due to the unknown matrix composition and lack of effective screening methods. To overcome this, a flexible screening platform was developed to evaluate enzyme treatment on fouling removal directly on RO membranes. The developed platform was used to identify enzymes that could degrade biofilms on fouled RO membranes. The membrane biofilms were destabilized by a range of enzyme groups, most effectively by proteases, lipases, DNase, cellulolytic enzymes, and pectin-degrading enzymes. The most effective enzyme formulations could clean the membranes more effectively than conventional chemical cleaning agents, removing 45 % of the biofilm compared with 0 %–19 % for the chemicals (p ≤ 0.001), indicating that enzymes have the potential to replace or complement chemical cleaning. The screening platform thus proved a potent tool for systematically studying biofilms and could be applied to combat biofilms in many other applications.

In-situ coating of Fe-TA complex on thin-film composite membranes for improved water permeance in reverse osmosis desalination

Post-modifications of thin-film composite (TFC) reverse osmosis (RO) membranes have been extensively studied to improve the overall separation performance. However, new approaches have yet to be explored not only to achieve better separation efficiency, but also to reduce the overall manufacturing cost. In this work, a ferric-tannic acid (Fe-TA) complex is post-coated onto the bare TFC membranes in an in-situ stepwise process. By optimizing the concentrations of Fe3+ and TA, the resulting membrane can achieve a water permeance of 3.58 L m−2 h−1 bar−1 (LMH bar−1) and a salt rejection of 98.37 % at 20 bar for brackish water desalination, owing to the improved surface hydrophilicity, roughness and additional water pathways. Moreover, the optimal membrane also exhibits comparable performance in seawater desalination and boron removal. This new approach of modification shows potentials to be integrated into the current roll-to-roll membrane fabrication process.

Field Evaluation of UF Filtration Pretreatment Impact on RO Membrane Scaling

Pretreatment of reverse osmosis (RO) feed water of high mineral scaling propensity was evaluated with respect to downstream RO membrane scaling, for two different feed pretreatment configurations. The pretreatment schemes included (i) media sand filtration, followed by a hydrocyclone (HC) and (ii) a hydrocyclone, microfilter, and a UF module, where both configurations included mesh screens for added protection. The first pretreatment configuration reduced the source water turbidity to ~0.5 NTU, while treatment that included UF feed yielded turbidity of <˜0.1 NTU; both pretreatment strategies provided feed water turbidity within the range recommended for RO desalination. Membrane scaling tests, with the pretreated water without antiscalant dosing, using a plate-and-frame RO unit and a membrane monitoring system, provided real-time membrane surface images that were quantified with respect to the progression of mineral scaling. RO desalting of source water pretreated with the first configuration revealed flux decline that was 75% greater and scale coverage (primarily gypsum) a factor of approximately eight higher relative to desalting of UF-treated source water. The results suggest that RO desalting of high mineral scaling propensity water can significantly benefit from added UF treatment to achieve feedwater turbidity to well below the typically recommended 0.5 NTU upper limit.

Modified Whale Optimization Algorithm based ANN: a novel predictive model for RO desalination plant

In recent decades, nature-inspired optimization methods have played a critical role in helping industrial plant designers to find superior solutions for process parameters. According to the literature, such methods are simple, quick, and indispensable for saving time, money, and energy. In this regard, the Modified Whale Optimization Algorithm (MWOA) hybridized with Artificial Neural Networks (ANN) has been employed in the Reverse Osmosis (RO) desalination plant performance to estimate the permeate flux (0.118‒2.656 L/h m2). The plant’s datasets have been collected from the literature and include four input parameters: feed flow rate (400‒600 L/h), evaporator inlet temperature (60‒80 °C), feed salt concentration (35‒140 g/L) and condenser inlet temperature (20‒30 °C). For this purpose, ten predictive models (MWOA-ANN Model-1 to Model-10) have been proposed, which are capable of predicting more accurate permeate flux (L/h m2) than the existing models (Response Surface Methodology (RSM), ANN and hybrid WOA-ANN models) with minimum errors. Simulation results suggest that the MWOA algorithm demonstrates a stronger optimization capability of finding the correct weights and biases so as to enable superior ANN based modeling without limitation of overfitting. Ten MWOA-ANN models (Model-1 to Model-10) have been proposed to investigate the plant’s performance. Model-6 with a single hidden layer (H = 1), eleven hidden layer nodes (n = 11) and the thirteen search agents (SA = 13) produced most outstanding regression results (R2 = 99.1%) with minimal errors (MSE = 0.005). The residual errors for Model-6 are also found to be within limits (span of − 0.1 to 0.2). Finally, the findings show that the screened MWOA-ANN models are promising for identifying the best process parameters in order to assist industrial plant designers.