Hygroscopic method application and realization for demineralization of sea and salted water

Seawater desalination is a vital source of drinking water, especially in coastal and remote areas. However, its sustainability is constrained by the high energy requirement. The need for fresh water supplies continues to rise due to its intensive use in many development sectors, such as agriculture and industry, as well as the continued increase in population. This has led to the idea of using nuclear power in seawater desalination to reduce the stress on the main electrical grid and enhance sustainable. The paper's goal is to optimize a reverse osmosis (RO) desalination plant to produce 100,000 m3 of fresh water daily. The best membrane is selected by testing 10 FilmTec membranes, with a focus on achieving optimal product quality (TDS) while maintaining an acceptable level of specific energy consumption (SEC). The study aims to address the challenge of delivering potable water by designing and modeling a standalone desalination plant powered by small modular reactors (SMRs). According to ROSA's analysis, the optimal RO desalination unit consists of two stages with a total of 175 membranes. The FilmTec SW30XHR-400 is identified as the best option based on superior water quality. This membrane has a specific energy consumption of 5.17 kWh/m3 and a low TDS of 141.4 mg/L. The total power consumption of the RO plant is approximately 21.5 MW; therefore, the KAREM-25 MWe reactor has been selected to be coupled with the RO desalination plant.

Membranes are widely used in industrial separation processes, particularly for gas separation and desalination processes. To develop membrane materials with improved permeability, selectivity can achieve more energy-efficient membrane separations and reduce costs. Since composite membranes offer improved performance, the aim of this research is to develop polymer-based composite membranes with improved performance for gas separation and water desalination applications. First, in order to obtain a composite membranes with high chlorine tolerance, a carbonaceous poly(furfuryl alcohol) (PFA) composite membrane was synthesized at a low temperature carbonation by formation and post-treatment of a thin PFA layer on porous polymer substrates. The carbonaceous PFA membrane exhibits high selectivity and excellent chemical stability in seawater desalination. The low-temperature carbonization method developed in this study is promising for developing a wide range of other carbonaceous polymer composite membranes for water desalination. Next, in order to apply PFA to other applications, understanding the effects of polymerization conditions on the properties of the PFA composite membrane is required. The PFA membrane was fully characterized in terms of microstructure and separation properties. Suitable synthesis conditions for the preparation of PFA composite membranes with smooth surfaces and uniform structure were (1) FA/ H2SO4 molar ratios: 74-300, (2) polymerization temperatures: 80-100°C and (3) solvents: ethanol and acetone. The preparation conditions were also optimized. The PFA composite membrane prepared with a FA/ H2SO4 molar ratio of 250, a polymerization temperature of 80°C and with ethanol as the solvent exhibited the highest H2/N2 ideal selectivity (αH2/N2=24.9), and a H2 permeability of 206 Barrers. This work led to a better understanding of the effect of the preparation procedures on the membrane performance. In order to investigate the effects of the incorporation of molecular sieve nanoparticles on the membrane structure and membrane performance, silicalite-poly(furfuryl alcohol) (PFA) mixed matrix composite membranes were successfully synthesized based on the best synthesis condition obtained previously. The silicalite-PFA mixed matrix composite membrane with 20% w/w silicalite loading had a high ideal selectivity (αo2/N2= 3.5 and αco2/N2= 5.4) and a good permeability (Po2= 821.2, Pco2= 1263.7, PN2= 233.3 Barrers) at room temperature. This membrane can be a good candidate for oxygen enrichment applications. Finally, in order to investigate the effects of the incorporation of silicalite nanocrystals on the desalination property of polyamide membranes, silicalite nanocrystals were also incorporated into polyamide matrix to synthesize silicalite-polyamide mixed matrix membranes. With an increase in the loading of silicalite nanocrystals, the water flux of silicalite-polyamide mixed matrix composite membranes increased whereas the salt selectivity significantly decreased. The silicalite-polyamide mixed matrix composite membrane prepared from TMC-hexane with 0.5% (w/v) silicalite had water flux of 2.7×10-6 m3/m2·s and NaCl rejection of 50% at a feed pressure of 34.5 bar which 2000 ppm salt solution was used as the feed. The silicalite-polyamide mixed matrix composite membrane is promising for developing high water flux composite membranes for water desalination. In this research, composite membranes with improved permeability, selectivity and chemical resistance were successfully synthesized for desalination and gas separation. For desalination, carbonaceous PFA composite membranes with high chlorine tolerance and silicalite-PA mixed matrix composite membranes with high salt rejection and water flux were successfully obtained. For gas separation, an optimized composite membranes PFA synthesis condition was found and silicalite-PFA mixed matrix composite membranes with high O2/N2 separation were successfully synthesized.

Hybrid membrane system for desalination and wastewater treatment : Integrating forward osmosis and low pressure reverse osmosis

The transition from fossil fuels to renewable energy sources is imperative to mitigate climate change and achieve sustainable development goals (SGDs). Hydrogen, as a clean energy carrier, holds great potential for decarbonizing various sectors, yet its production remains predominantly reliant on fossil fuels. This study explores a novel approach to sustainable hydrogen production by integrating offshore wind energy with reverse osmosis (RO) desalination technology. The proposed configuration harnesses offshore wind power to energize both a RO desalination system and water electrolysis unit. Initially, the wind energy powers the RO desalination process, purifying seawater, and then desalinated water is directed to water electrolysis system for generating green hydrogen directly from seawater. The resulting renewable hydrogen holds potential for diverse applications, including marine industries, and can be transported onshore as needed. The RO system is configured to treat 20 kg s−1 of seawater with a salinity of 35 000 ppm, aiming for a high recovery ratio and reduced freshwater salinity. A pressure exchanger (PX) is integrated to recover energy from high‐pressure brine stream and transfer it to the low‐pressure feed water, thus reducing the overall energy consumption of the RO process. The concentrated brine extracted from RO desalination is proposed to be utilized for the production of sodium hydroxide that can further pretreat incoming seawater and enhance the effectiveness of the filtration process by mitigating membrane fouling. This pressure exchanger increases the energy efficiency of the RO system from 63.1% to 64.0% and exergetic efficiency from 13.9% to 18.2% increasing the overall first and second law efficiencies to 37.9% and 33.5%. By leveraging offshore wind power to drive RO desalination systems, this research not only addresses freshwater scarcity but also facilitates green hydrogen generation, contributing to the advancement of renewable energy solutions and fostering environmental sustainability.

Desalination is probably the only means for fresh water supply to countries in decertified climate. The majority of GCC counties rely on desalinated water for fresh water supply to major cities. Over 70% of the desalinated water in the GCC comes from thermal desalination plants including Multi Stage Flash (MSF) and Multi Effect Distillation (MED). The new trend in the desalination plant in the GCC is 30% Reverse Osmosis (RO) and 70% thermal. However, these percentages vary from one to another country depending on feed water quality and expertise. For example, Oman Sea has lower salinity than the Gulf water and hence Oman uses more RO for desalination than MED and MSF. This decision is also driven by economy as RO process less energy intensive and hence the produced water is less expensive as compared to thermal plants. On the contrary, Qatar and Kuwait use more MSF followed by MED due to the high salinity and low quality feed water. This is also because trials of RO in both Qatar and Kuwait were not successful because of the problems of membrane fouling and restrict pre-treatment requirements due to the quality of the water intake.The advantages of RO over thermal technologies are well known in terms of lower energy consumption and the cost of produced water; but are not yet taken advantage of in the GCC zone. One of the reasons is blamed on high feed water salinity and bad water quality; other reasons such as lack of experience, red tides and reliability are contributed to the dominance of thermal plants. However, field experience showed that good pretreatment and optimized RO design may overcome the problems of high feed salinity and bad water quality. Several RO plants, such as Fujairah in UAE, are good examples of a working RO technology in the harsh water environment. Good RO design includes design and optimization of both pretreatment and post-treatment. Field experience showed that most of RO plants failure was due to inefficient pretreatment which resulted in providing low quality water to the RO membrane that caused fouling. Fouling, including biological and scaling, can be handled once an efficient pretreatment process is available. Recent advances in pre-treatment techniques include the combination of Forward Osmosis (FO) with RO among other methods. Recent studies by the authors including commercial implantations have shown that the combination of FO with RO addresses the most technical challenge of RO process and that is fouling, which results in lower energy consumption and less chemical additives. Experience showed fouling in FO process in reversible, i.e. can be removed by backlashing while fouling in conventional RO process is irreversible.In this study, the feasibility of integrating FO with RO process for the desalting of the Gulf water in Qatar is presented. The results are expressed in terms of specific energy consumption, process recovery, produced water quality, chemical additives and overall process cost.The implementation of RO for desalination is not only reducing the cost of desalination but also the environmental impact. More R&D should be done to provide useful data about RO application and suitability for the Gulf water. The R&D should be focused on laboratory to market development of RO technology using rigorous lab scale and pilot plant testing program.

Purpose: review of existing technologies and methods of seawater desalination for drinking water supply. Discussion. Based on modern research methods using statistical data and a review of domestic and foreign literature, a review of methods and technologies for desalination and desaltation of highly mineralized natural waters was carried out. The use of sea water for domestic purposes is impossible due to the high content of minerals, however, after desalination, such water can be used for drinking. The choice of technologies and methods of desalination is primarily determined by the quality of source water, as well as the requirements for the quality of treated water, plant productivity and technical and economic calculations. For the drinking water supply purposes, the most efficient and cost-effective method is desalination using reverse osmosis technology, used for both sea and groundwater with high salinity. Reverse osmosis technology has significant advantages over thermal desalination, especially when applied to small-scale plants of small domestic water supply systems. The use of reverse osmosis plants will significantly increase productivity of drinking water output per watt of electricity consumed. Conclusions. The introduction of modern technologies and careful attention to water consumption play a significant role in maintaining water balance in different countries. The most cost-effective and efficient method is seawater desalination using reverse osmosis plants. Despite the fact that water desalination and desaltion plants are very expensive, the conservation of natural waters is a priority nowadays.

This paper explores the application of genetic algorithms (GA) for optimal design of reverse osmosis (RO) water desalination systems. While RO desalination is among the most cost and energy efficient methods for water desalination, optimal design of such systems is rarely an easy task. In these systems, salty water is made to flow at high pressure through vessels that contain semi-permeable membrane modules. The membranes can allow water to flow through, but prohibit the passage of salt ions. When the pressure is sufficiently high, water molecules will flow through the membranes leaving the salt ions behind and are collected in a fresh water stream. Typical system design variables for RO systems include the number and layout of the vessels and membrane modules, as well as the operating pressure and flow rate. This paper explores models for single and two-stage RO pressure vessel configurations. The number and layout of the vessels and membrane modules are regarded as discrete variables, while the operating pressures and flow rate are regarded as continuous variables. GA is applied to optimize the models for minimum overall cost of unit produced fresh water. Case studies are considered for four different water salinity concentration levels. In each of the studies, three different types of crossover are explored in the GA. While all the studied crossover types yielded satisfactory results, the crossover types that attempt to exploit design variable continuity performed slightly better, even for the discrete variables of this problem.

Triggered by the Kyoto Protocol and by the aggravation of freshwater scarcity, environmental impacts should soon become key decision criteria for the planning of potable water supply projects, especially when advanced systems such as seawater desalination are at stake. In order to foster the transition of the water industry towards sustainable practices, the present work proposes an integrated design approach dedicated to potable water supply that targets both economic and environmental objectives. At first, the current industrial practices (Chapter I) and the technical characteristics of potable water supply systems (Chapter II) are analyzed via the modeling of the process units used for potable water supply: pumping systems, conventional water treatment processes (e.g. clarification, filtration, disinfection) and advanced water treatment processes (e.g. membrane processes, thermal processes). Using the ISO 14040 standardized Life Cycle Assessment (LCA) method, Chapter III presents the development of a performance indicator that assesses the environmental impacts generated through all stages of the life cycle of potable water supply (i.e. from cradle to grave): from the construction of the potable water treatment plant, to its operation and decommissioning. This LCA-based indicator provides a holistic overview of all potential environmental impacts (e.g. green house gases (GHG) emissions, impacts on ecosystems and on human health). It allows to stress out the impact sources and the penalizing steps within potable water supply (Chapter IV): The production of electricity and chemicals required by the potable water treatment plant is highlighted to generate respectively 75% and 15% of the total impacts generated during the life cycle of potable water supply. Different potable water supply scenarios (e.g. potable water supply from ground water, from surface water, seawater desalination, water import from distant water resources) are benchmarked, in order to identify the best solutions as a function of the local context (e.g. type of electricity supply, topographic conditions, feed water quality). Based on the results of the environmental assessment, Chapter V proposes measures for the improvement of the industrial practices of the water sector, targeting energy and chemicals management, electricity sourcing and effluent disposal. Within the same perspective, Chapter VI details an optimization method for the design of the reverse osmosis (RO) membrane process, i.e. the key treatment process for desalination and wastewater reclamation. This method systematically synthesizes RO process configurations and evaluates their performances on economical (total annualized costs), technical (energy requirement, water conversion rate) and environmental criteria (GHG emissions). Evolutionary algorithms are then used to optimize the design of these configurations (process layout and operating conditions) and to identify those featuring the best trade-offs between economical costs and environmental impacts. As case study, the optimization method is applied on a brackish water reverse osmosis (BWRO) desalination project. The characteristics of the optimal BWRO process configurations are calculated as a function of the project constraints (e.g. economical and technical settings, minimum potable water quality), in order to illustrate how this method may support process engineers for the design of desalination plants.

A systematic measurement of ions and 2H/1H, 7Li/6Li, 11B/10B, 18O/ 16O, and 87Sr/86Sr isotopes in feed-waters, permeates, and brines from commercial reverse osmosis (RO) desalination plants in Israel (Ashkelon, Eilat, and Nitzana) and Cyprus (Larnaca) reveals distinctive geochemical and isotopic fingerprints of fresh water generated from desalination of seawater (SWRO) and brackish water (BWRO). The degree of isotope fractionation during the passage of water and solutes through the RO membranes depends on the medium (solvent-water vs. solutes), chemical speciation of the solutes, their charge, and their mass difference. O, H, and Sr isotopes are not fractionated during the RO process. 7Li is preferentially rejected in low pH RO, and B isotope fractionation depends on the pH conditions. Under low pH conditions, B isotopes are not significantly fractionated, whereas at high pH, RO permeates are enriched by 20 per thousand in 11B due to selective rejection of borate ion and preferential permeation of 11B-enriched boric acid through the membrane. The specific geochemical and isotopic fingerprints of SWRO provide a unique tool for tracing "man-made" fresh water as an emerging recharge component of natural water resources.

Seawater desalination in China: Retrospect and prospect

Change of editorial structure at Social Science & Medicine

Removal and Recovery of Phosphonate Antiscalants

The integration of desalination plants and mineral production

Performance evaluation of reverse osmosis desalination plant: A case study of Wadi Ma'in, Zara and Mujib Plant

A feasibility study of a small-scale photovoltaic-powered reverse osmosis desalination plant for potable water and salt production in Madura Island: A techno-economic evaluation