Seawater Desalination Plant Research Articles

Assessment of the economic viability, environmental, and social impacts of green hydrogen production: an Algerian case study

The impacts of climate change are real and in many parts of the world testify to its harsh reality, including rampant extreme weather events, droughts, heat, wildfires, and flooding which have recorded in places which have not experienced them in recent memory. In the quest to avert such events, there is a growing awareness and demand for sustainable processes and operations. Today, sustainability encompasses a balance between ecological footprint and human development index, taking into consideration economics, the green environment, safety, quality, ethics, diversity and inclusion (D&I), and communities. This article presents some steps that have been taken by Algeria to balance energetic autonomy and sustainable development, and a case study on green hydrogen production employing membrane processes. Algeria’s objective to join the global fight against climate change is to develop its green hydrogen base. Given its resources, including available solar and wind power, seawater desalination plants, building capacity, and its favorable location, it is developing its green hydrogen economy to supply hydrogen, especially to Europe. This presents an opportunity for other developing nations, especially in Africa, to gain from this experience.

Evaluation of suitable sites for concentrated solar power desalination systems: case study of Mauritania

It is imperative to address the critical problem of water scarcity in sub-Saharan Africa, especially in light of the aggravating effects of climate change brought on by the extraction of fossil fuels. In order to ensure the availability of drinkable water in these places, this research proposes integrating concentrated solar power (CSP) with desalination systems (DS). Present research is focused on identifying and evaluating potential locations for DS/CSP implementation within Mauritania by employing a comprehensive, multi-criteria decision-making framework. This framework synthesizes mathematical approaches from multi-criteria analysis with geospatial analysis techniques, considering a range of factors including environmental impact, economic viability, demographic demands, and climatic conditions. Research findings reveal that 10% of the Mauritanian, approximately 103070 km2, presents optimal conditions for the deployment of DS/CSP facilities. The study delineates the coastal regions as prime candidates for seawater desalination plants, while the densely populated southeastern areas are identified as suitable for brackish water desalination systems. Conversely, the less inhabited northern territories hold the potential for decentralized brackish water desalination plants. Hence this study provides a holistic approach for DS/CSP systems installation to manage water scarcity as well as energy security issues in Mauritania. And also provides basis for formulating future policies in the region.

Enhancing remineralization in seawater desalination: Optimizing reagent injection for improved water quality at AL HOCEIMA plant

The water quality produced by reverse osmosis is aggressive and highly demineralized, making it unsuitable for direct use and consumption as a source of drinking water. For this reason, the remineralization stage plays a crucial role in the treatment of desalinated water, and its improvement will be necessary to solve the problem of the aggressiveness of the water treated at the AL HOCEIMA seawater desalination plant. This improvement involves injecting three reagents into the limewater saturator, to obtain lime water that ensures the turbidity of the treated water is less than or equal to 1NTU, TAC, equal to 8°F. These reagents are polyelectrolyte, ferric chloride, and sodium silicate. The results show that adding polyelectrolyte and ferric chloride reduces turbidity to an acceptable level for the plant. However, it should be noted that ferric chloride has significant effects on other treated water parameters. These findings underscore the importance of optimizing remineralization processes to meet water quality standards effectively.

A novel system based on a series of ORCs to recover cryogenic energy from the LNG regasification process for power and freshwater production

Seawater desalination emerges as a feasible solution to solve the issues related to the freshwater scarcity generated by climate change. In the meantime, the energy transition promotes using Liquid Natural Gas (LNG) as a cleaner fuel. Usually, it is stored near marine areas at 113 K, therefore the recovery of part of the exergetic cold potential for freshwater production appears very appealing. In light of this, this study evaluates the energy and exergy performances of an innovative seawater desalination plant supplied by the cryogenic power released in the LNG regasification process. Specifically, three Organic Rankine Cycles (ORCs) arranged in series, operating between the seawater (hot source) and LNG (cold source) thermal levels, are investigated. Seawater releases heat to promote the evaporation of proper low-boiling fluids, cooling down to −5.62 °C and forming a two-phase mixture consisting of 50 wt% of pure ice and brine, so that the same liquid phase is employed for ice transportation in post-treatment devices. Simultaneously, the LNG is preheated by the low-boiling fluids’ condensation heat, allowing for the limitation of the thermal energy required for the phase change. Power generation is obtained by turboexpanders located between vaporizers and condensers. Eighteen different ORC configurations using diverse working fluids were analysed assuming steady-state conditions and ideal transformations. Considering a regasification terminal with a capacity of 8 billion Sm³ per year, the maximum power production amounts to 11.24 MW, recovering 13.33% of thermal exergy and producing 137.5 kg/s of freshwater. When desalination is privileged, 149.9 kg/s of freshwater can be produced, generating a power output of 7.02 MW with an exergetic recovery efficiency of 8.32%.

Modelling and optimising of MED-TVC seawater desalination plants assisted with electric heaters

One major issue with MED-TVC systems, a widely used thermal-based desalination technology, is their high energy consumption and carbon emissions. This underscores the importance of optimising and integrating these thermal-based desalination technologies with sustainable energy systems to utilize their waste heat and enhance the performance of these plants effectively. This research aimed to optimize and address the environmental challenges of MED-TVC desalination plants in areas with insufficient sunlight, unstable weather conditions, and limited economic resources. To this end, a model of an electric heater for generating thermal energy coupled with an optimized MED-TVC desalination plant was proposed. The MED-TVC section was optimized by incorporating an additional ejector in the final stage of MED-TVC demonstrating an increase of over 11 % in evacuating non-condensable gases from the last effect and increasing the product water by up to 14.89 %. Regarding the design of the electric heating elements used in electric heaters, the use of one-plus-two U-tubes with helical baffles was more efficient than multi-layer U-tubes with segmental baffles as improved the pressure loss of the thermal fluid by 25 % and increased the heat transfer coefficient of the heating elements to 18 %. The power section was also equipped with an off-grid system to provide the necessary power for the equipment of the proposed model. In the economic analysis of employing a parabolic trough solar collector and electric heaters, not only were the direct costs of the electric heaters almost equal to just 40 % of the direct costs of the parabolic trough solar collector approach but also the required thermal fluid was 50 % of the solar case.

Integration of CaO2/Fe2+ and ultrafiltration acts as multiple-workfunctions pretreatment for seawater desalination during harmful algal blooms

This study employed calcium peroxide/ferrous iron (CaO2/Fe2+) as an innovative pretreatment strategy for seawater reverse osmosis (SWRO) operation during harmful algae blooms (HABs). CaO2/Fe2+ showed improved coagulation performance compared to conventional coagulation (Fe3+ coagulant). The dynamic dominance of foulants between micro-particles and algal organic matters (AOMs), due to the different dosages of CaO2/Fe2+, was found to be crucial in reducing ultrafiltration (UF) fouling. As a result, the optimal dosage of 0.05 mM/0.1 mM of CaO2/Fe2+ achieved a higher reduction of 71.6 % of modified fouling index (MFI) compared to conventional coagulation (38.1 % via 0.1 mM Fe3+). Specifically, CaO2/Fe2+ demonstrated a greater capacity to remove micro-particles across size ranges of 1–5 μm and various AOMs (i.e., biopolymer and humics) in algae-laden seawater compared to conventional coagulation. This resulted in reduced flux decline and less accumulation of algal cells, proteinaceous substances and humics on membrane surfaces, which were validated through Optical-Photothermal Infrared Spectromicroscopy (O-PTIR) with sub-micron resolution. Additionally, CaO2/Fe2+ reduced dissolved Fe3+ in UF permeate, and generated combined chlorine simultaneously with disinfection effects on marine algae (evidenced by O-PTIR and Raman spectroscopy). Thus, it would reduce fouling of subsequent SWRO membranes. Overall, CaO2/Fe2+ presents a multiple-workfunctions pretreatment method for HAB mitigation in seawater desalination plants.

Design of SWRO Desalination Plant for Nuclear Research Center

Libya has an infinite water resource available inthe coastal towns and cities being located on Mediterranean Sea with 1950km coast. Therefore, the need for desalinatedwater for Nuclear Research Center NRC located in Tajurais currently about 1200 m3/day. To cover the center presentand future water needs for research and developmentactivities, two thermal sea water desalination plants have been assembled in the site. One of the plants uses MultiStage Flash technology and the other one uses Multi EffectDesalination technology with capacity of 1200m/day eachone. Detailed design for 1200m3/day seawater reverseosmosis SWRO unit is carried out using ROSA S oftware to make the technical comparison with other MSF and MEDunits. The unit labeled an S W30XLE-440i by the results ofthe Software is selected since it required the lower feedpressure of 55.5bar and highest salt recovery of 45% with total dissolved solid of 190ppm. From the technical point ofview, the study showed that SWRO required lower seawater inlet flow rate than MSF and MED. The unitsefficiency are 43%, 10.5% and 25% for SWRO, MSF, andMED, respectively. Further the Product quality TDS 190ppm for RO unit is suitable for drinking water, whilethose of MSF and MED 50ppm. Energy consumption asheating steam is not required for the S WRO unit; however,a steam flow rate 7.3m 3/hr is required by MSF and MEDunits. These make SWRO unit friendlier to the environment and most proper technically under these situations.

Feasibility study of hybridizing a solar power plant with a small modular reactor for seawater desalination

The article discusses the technical and economic analysis of a seawater desalination plant, where the power source is a hybrid of solar and nuclear energy, as they are considered the cleanest energy sources compared to fossil fuel power plants. The source of nuclear energy in this study is a small modular reactor (SMR). This plant also uses a hybrid of seawater desalination systems: either a reverse osmosis plant with a multi-effect distillation (RO + MED) unit, or a reverse osmosis plant with a multi-stage flash distillation (RO + MSF) unit. Small modular reactors can be used for other applications besides generating electricity, as they produce high-temperature steam which can be used in many industrial processes such as hydrogen production and seawater desalination. Small modular reactors are also considered to be more cost effective, safer, more flexible and have a greater number of applications compared to high power reactors. The analysis is based on calculating the cost of producing of one cubic meter of fresh water using this hybrid desalination plant and comparing the results with those of desalination plant integrated with a power plant that uses exclusively nuclear energy as a source of thermal and electrical power, which uses the VVER-1200 reactor. Also, this study studies the impact of the degree of hybridization, that is, the ratio of power used from solar energy to power used from nuclear energy, on the cost of desalination of one cubic meter of water, as well as on the quality of the desalinated water.

Hydration Characteristics of Slag-Ca(OH)2-Al2O3 Binder in a 60 °C Curing Environment with Brine as Mixing Water

Recently, research results on PC-based or alkali-activated slag cement (AASC) using seawater as mixing water have been reported. Unlike seawater, reverse osmosis brine (brine) is waste discharged into the ocean from seawater desalination plants. There is a need to develop new and effective methods of disposing or utilizing brine to reduce marine pollution, protect marine ecosystems, and increase marine plant construction. However, research on cement or concrete using brine as a mixing water is very limited. Brine has almost the same composition as seawater, and the ion concentration is 2–4 times higher. Therefore, it is believed that new methods of using brine can be investigated and developed based on existing research and experimental results on seawater. The effects of brine and aluminum oxide (AO) on activated slag with calcium hydroxide (CH) were investigated for hydration and mechanical properties. 5% and 10% of CH were used, and samples using fresh water (FC) were prepared at the same time for comparison with brine. The slag sample without CH has a low initial (1 and 3d) strength of about 10 MPa for both FC and brine, but increases rapidly from 7d. Incorporation of CH was effective in improving the mechanical performance of FC and brine samples. In addition, the brine sample exhibited higher strength than the FC sample because it formed fewer C3AH6 phases that cause volume instability than the FC sample and affected the hydration promotion of slag particles. And more calcite phases were observed in the brine samples than in the FC samples. Through this study, the possibility of using brine as a building material was confirmed. In addition, the effect of chloride ion adsorption of slag mixed with AO and CH on the physical properties and mechanical performance of the hydration reaction was confirmed.

Integrated water quality and performance assessment of seawater desalination plants along two coasts in Egypt

This study aims to assess feedwater, brine, and drinking water quality related to eight full-scale Egyptian seawater desalination plants. Collected water quality records from plants on the Mediterranean and Red Seas were monthly analyzed to identify different physical, chemical, and biological parameters during 2022. Statistical analysis and water quality indices (WQIs) approaches were applied to evaluate the various water quality states based on the available international and Egyptian guidelines. Analyzed seawater quality properties showed compliance with the most operating permissible limits except for high concentrations of turbidity, fats, oils, and greases, total bacteria in one plant, and iron, manganese, and silica in another plant. The monthly measured Weighted Arithmetic WQI classified 71 % and 100 % of desalination plants as having “Excellent” water rank according to the standard limits of the World Health Organization and the Egyptian Water Quality Standard, respectively. However, 65 % and 52 % of desalination plants were projected into the “good” water quality rank based on the Canadian Council of Ministers of the Environment WQI for the same guidelines. The results indicate that the feed intake type and the location of a desalination plant can optimize its performance efficiency, minimize contamination sources, and mitigate the potential environmental impacts of brine.

Integration study of a reverse osmosis desalination plant in a hydroelectric pumping station

The archipelagos of Macaronesia (Canary Islands, Azores, Madeira and Cape Verde) have isolated energy systems (IES). This makes the island systems dependent on themselves for energy production. In the case of an island like Gran Canaria, energy production is mainly obtained from: a) Wind and solar energy, 19 % of the total energy produced, b) Energy obtained from the burning of fossil fuels in the energy production equipment of the existing power plants. Thermal power plants, 81 % of the total energy produced. It is necessary to find a solution to the current production system, which is already partially obsolete and must be renewed and/or dismantled, in order to avoid "Zero Energy", which implies a change in the production cycle. In addition, the incorporation of the "Chira-Soria" pumped-storage hydroelectric power plant into the Gran Canaria electricity system represents another, even more important, change in the dynamics followed up to now. Basically, this plant, hydraulically stabilized by means of a seawater desalination plant, incorporates energy storage by storing water at high altitude to be turbined under the right conditions. The new situation with this incorporation will be analysed and the option of integrated operation in the overall energy system of Gran Canaria will be assessed.

Improving Reliability in Al Hoceima Seawater Desalination Plant by Failure Modes, Effects, and Criticality Analysis Model

Improving Reliability in Al Hoceima Seawater Desalination Plant by Failure Modes, Effects, and Criticality Analysis Model

Wear Behaviors of the Surface of Duplex Cast Steel after the Burnishing Process.

Duplex steel and cast steels have a wide range of applications in many industrial sectors, for example, oil extraction, printing, petrochemical industry, energy-exhaust gases desulphurization systems, seawater desalination plants, and the shipbuilding industry. The machine elements can be produced with different techniques, which determine the operational properties. A material with the same chemical composition made as a casting will have worse mechanical properties than, for example, a forged element. This depends on the microstructure, its fragmentation and its morphology. However, the costs of casting are lower than, for example, forging, and, in addition, not all shapes obtainable in the casting process can be made using metal-plastic working methods. This article presents research results concerning the influence of the burnishing process on the properties of the duplex cast steel surface layer. The purpose of the research was to verify the impact of static pressure roller burnishing (SPRB) parameters on the wear of the surface layer of duplex cast steel. The subject of the research was cast steel in the GX2CrNiMoN22-5-3 grade-according to PN-EN 10283:2019-that was burnished using 15 variants of technological parameters. Then, the samples were subjected to surface wear tests using the INSTRON 8874 device. On the basis of the observed wear appearances, the acting wear mechanisms are defined and evaluated according their contribution to the wear behavior. Detailed information about the wear phenomena will help industries to minimize their maintenance losses related to surface wear. The possibility of shaping surface properties by mechanical burnishing is part of the current direction of surface engineering development. This technology, combined with a high-potential material such as duplex cast steel, makes it possible to increase wear resistance.

Non-target screening and prioritization of organic contaminants in seawater desalination and their ecological risk assessment

The impact of desalination brine on the marine environment is a global concern. Regarding this, salinity is generally accepted as the major environmental factor in desalination concentrate. However, recent studies have shown that the influence of organic contaminants in brine cannot be ignored. Therefore, a non-targeted screening method based on comprehensive two-dimensional gas chromatography-quadrupole mass spectrometry (GC × GC-qMS) was developed for identifying organic contaminants in the desalination brine. A total of 404 compounds were tentatively identified from four seawater desalination plants (three reverse osmosis plants and one multiple effect distillation plant) in China. The identified compounds were prioritized based on their persistence, bioaccumulation, ecotoxicity, usage, and detection frequency. Twenty-one (21) compounds (seven phthalates, ten pesticides, four trihalomethanes) were then selected for further quantitative analysis and ecological risk assessment, including compounds from the priority list along with substances from the same chemical classes. Ecologically risky substances in brine include diisobutylphthalate and bis(2-Ethylhexyl) phthalate, atrazine and acetochlor, and bromoform. Most of the contaminants come from raw seawater, and no high risk contaminants introduced by the desalination process have been found except for disinfection by-products. In brine discharge management, people believed that all pollution in raw seawater was concentrated by desalination process. This study shows that not all pollutants are concentrated during the desalination process. In this study, the total concentration of pesticide in the brine increased by 58.42%. The concentration of ∑PAEs decreased by 13.65% in reverse osmosis desalination plants and increased by 10.96% in the multi-effect distillation plant. The concentration of trihalomethane increased significantly in the desalination concentrate. The change in the concentration of pollutants in the desalination concentrate was related to the pretreatment method and the chemical characteristics of the contaminants. The method and results given in this study hinted a new idea to identify and control the environmental impact factors of brine.

Experimental and theoretical investigations of the anti-corrosion film derivated from bio-based melatonin on AA5052 aluminum alloy surface

In this work, the effect of the bio-based melatonin (MEL) on the corrosion inhibition of AA5052 aluminum alloy in 3 wt% NaCl solution has been studied by weight-loss experiments, electrochemical measurements and surface analysis. MEL inhibits the corrosion of AA5052 aluminum alloy in 3 wt% NaCl solution very well, resulting in a positive shift of the corrosion potential and the pitting potential. The corrosion inhibition efficiency reaches 71.76% at 2 mM MEL. The FT-IR, SEM, XPS and theoretical calculation are used to investigate its corrosion inhibition mechanism. It indicates that MEL coordinates with Al3+ ions via its N (9) atom and O (10) atom to form a surface complex film. This protective film retards the corrosion of AA5052 aluminum alloy significantly. This biomolecule is a promising anti-corrosion additive to protect aluminum alloys heat-exchange in seawater desalination plant.

Cost Studies of Reverse Osmosis Desalination Plants in the Range of 23,000–33,000 m3/day

The analysis of energy consumption in reverse osmosis desalination plants is the most important and relevant factor to study, because this parameter indicates the level of efficiency and competitiveness of the plant. The direct consequence of the high specific energy consumption (SEC) of a desalination plant in the production of water is one of the main obstacles to the exponential expansion of this technology worldwide. The methodological procedure used to carry out the work is based on the analysis of energy consumption, maintenance costs, staff, membranes, and reagents of three desalination plants with a production of more than 23,000 m3/day located in the Canary Islands (Spain); all data are obtained from real analyses collected “in situ” from 2015 to 2018. One of the main objectives of the current research on desalination plants is to reduce the SEC of seawater desalination plants (SWRO), incorporating energy recovery systems (ERS) and high efficiency pumps (HEP), and to implement different operational configurations with the aim of minimizing the energy requirements necessary to obtain a good product quality at minimum production cost.

Cost-based optimization, feasibility study, and sensitivity analysis of forward osmosis/crystallization/reverse osmosis with high-temperature operation for high-salinity seawater desalination

Seawater desalination plants using reverse osmosis (RO) in high temperature and high-salinity conditions, such as in the Middle East, face challenges such as limited achievable recoveries and high energy costs. This study evaluated the economic feasibility under seawater and high-salinity conditions by introducing a forward osmosis/crystallization/reverse osmosis (FO/Cry/RO) hybrid process. The optimization results were then used to compare the specific water cost (SWC), specific energy consumption (SEC), recovery, and permeate quality of the hybrid process with two different draw solutes and a conventional seawater RO process. In addition, a sensitivity analysis was conducted to determine how individual process parameters and operating conditions affect the economic feasibility of the proposed process under seawater and high-salinity conditions. The FO/Cry/RO hybrid process achieved a higher recovery with a lower SWC and SEC as the feed concentration increased compared to the conventional RO process. Utilizing waste heat further increased the economic advantages of the proposed process. In addition, much higher permeate quality can be obtained depending on the type of draw solute. The results of this study revealed that the proposed hybrid system outperformed the conventional RO process in terms of both energy efficiency and cost-effectiveness for seawater desalination under high-temperature and high-salinity conditions.

Thermochemical modeling and performance evaluation of freeze desalination systems

Freeze desalination (FD) is a method in which saline water is cooled below its freezing point and freshwater is separated from the brine in the form of ice crystals. FD is relatively insensitive to the salinity of the feed solution, making it suitable for desalination of high concentration brines such as the brine rejected from the seawater desalination plants. The design of the FD system and the thermochemical behavior of the brine upon freezing are critical factors in the energy performance of this method. To date, thermochemical properties of the concentrated seawater during cooling, such as the threshold of formation of ice and salt-hydrates and their corresponding cooling load of formation, are not well known. Likewise, the optimal configuration of the FD system to achieve the maximum energy efficiency has not been investigated. This work provides comprehensive data about the cooling load of freezing of concentrated brine rejected from seawater desalination plants along with the threshold of formation of ice and salt-hydrates backed-up by validation. Furthermore, the optimal configuration of the FD system is identified and the effects of the compressor isentropic efficiency and effectiveness of the system's heat exchangers on the work consumption of the FD system were investigated.

A Case Study of a Reverse Osmosis Based Pumped Energy Storage Plant in Canary Islands

Gran Canaria, due to its status as an island, has an isolated energy system (IES). This has made it dependent on itself for energy production, which is basically obtained from: (a) Wind and solar energy, which equals 19% of the total energy produced, (b) Energy obtained from the burning of fossil fuels in the energy production equipment of the existing thermal power stations, which equals 81% of the total energy produced. A solution must be found to the current production system, which is already partially obsolete and is due for renewal and/or decommissioning, in order to avoid “Energy Zero”, which means a change in the production cycle. In addition, the incorporation of a pumped hydroelectric energy storage plant “Chira-Soria” into the Gran Canaria electricity system represents another, even more important, change in the dynamics followed up to now. Basically, this plant, which is hydraulically stabilized by means of a seawater desalination plant, incorporates energy storage by storing water at high altitude to be turbined under appropriate conditions. The new situation will be analyzed with this incorporation and the option of an integrated operation in the overall energy system of Gran Canaria will be considered.

Bio-inspired design of next-generation ultrapermeable membrane systems

Ultrapermeable membranes (UPMs) have the potential of improving water production efficiency. However, operating at high water fluxes will intensify concentration polarization and membrane fouling. Inspired by the V-formation of birds in nature we propose a transformative membrane module that enables a doubled mass transfer coefficient with a moderately increased friction loss coefficient. Moreover, we present a practical technological pathway for the UPM systems to achieve 338% improvement of average water flux and 18% energy savings relative to state-of-the-art seawater desalination plants. The work makes it practical to operate at a high average water flux of 84 L m−2 h−1 with a controlled concentration polarization for the UPM systems. It breaks through the module development bottlenecks for the next-generation UPM systems and has enormous potential application for alleviating water scarcity crisis in the coming decades.