Search

The release of seawater desalination brine with a salt concentration about two times that of seawater without any treatment may cause serious environmental problems. Moreover, because of the higher concentration of dissolved salts present, the amount of recoverable resources is greater, but the impurities become more difficult to control. In this study, we conducted a three-step process to recover Mg resources from seawater desalination brine with Mg concentration of 2,340 mg/L, and determined the optimal conditions for minimizing the impurities and maximizing Mg recovery efficiency at each step. The process was as follows: (1) pre-precipitation of Mg using paper sludge ash (PSA) (PSA:brine = 1:40) (g:mL), (2) dissolution of Mg using 1.0 M sulfuric acid (H2SO4) corresponding to one-fifth of the brine volume, and (3) precipitation of magnesium sulfate (MgSO4) using ethanol (solution:ethanol = 1:1) (mL:mL). Under the optimal conditions, the reaction efficiencies of the three steps were determined to be 98%, 70.8%, and 88%, respectively, and the overall efficiency of recovering Mg from the seawater desalination brine was 61.1%. The MgSO4 obtained in this study contained no impurities other than Ca, comprising as much as 6.7% of the precipitate. [ABSTRACT FROM AUTHOR]

For the past several decades, we have seen significant improvements in the desalination industry, mostly intended to increase efficiency and reduce the energy consumption of desalination plants but also to improve the reliability, operability, and longevity of membrane systems. Except for introducing pressure exchanger energy recovery devices, most improvements have been incremental rather than disruptive; in most cases they were small adjustments that made a plant more effective, efficient, or reliable. This paper describes a completely disruptive new method of desalinating seawater: subsea desalination. A patented method combining seawater reverse osmosis (SWRO) membranes with subsea technology is well-proven and has been used extensively in the offshore oil and gas industry for decades. The subsea desalination concept places a membrane desalination plant below sea level, obtaining two very immediate and distinctive benefits: (1) higher and consistent feed water quality and (2) hydrostatic pressure from the column of water that provides all the required pre-membrane pressure. In the paper, we will describe the subsea system design and its advantages, which are substantial and game-changing, explaining how the cost of water can be reduced, reliability improved, and environmental benefits enhanced with such a solution. Specific benefits of the membrane configuration will be discussed, describing the system advantage regarding energy consumption, permeate quality and reduced brine salinity. The paper also presents the set-up and results of subsea field tests where it was proved that the reverse osmosis (RO) membranes performed as predicted by the DuPont WAVE design software. [ABSTRACT FROM AUTHOR]

Mining valuable minerals from desalination concentrate is a promising path to improve resource utilization efficiency and reduce the environmental impact. With the rapid expansion of the desalination industry and the improvement of extraction technology, the comprehensive utilization of desalination concentrate is approaching commercial reality. This paper summarized the development status of the desalination industry within and outside China. On this basis, the economic potential of valuable minerals mining from seawater desalination concentrate was estimated. Our results showed that when the in-operation membrane desalination projects in China run at full capacity, the discharge of seawater concentrate is about 1,696,900 m3/d. The high commercial potential chemicals are boron, lithium, and rubidium because of their high concentration and unit price. If continuous production can be achieved, its economic value will be more than desalinated water production. In addition, this paper summarized the extraction technologies of magnesium, potassium, rubidium, boron, strontium, and lithium in desalination concentrate. [ABSTRACT FROM AUTHOR]

Water scarcity is being recognized as one of the main threats that mankind is facing globally. Reverse osmosis membrane technology has developed as a promising technology to address this problem. This increase has been driven as materials are improved and costs dropped. This is especially relevant for Middle East countries (ME), where population is located in arid and semi-arid regions with limited rainfalls and a high degree of evaporation due to the high temperatures the region is exposed to. Therefore, getting a robust element that is able to offer a stable salt rejection even after multiple cleanings is of utmost importance to sustain the population and economic growth of the region. This paper aims at demonstrating the superior durability of FilmTec™ membranes compared to other manufacturers. This superior durability has been reported in a number of desalination plants where FilmTec™ membranes lifetime has exceeded more than 10 years, but a quantification and a reliable comparison of such superior durability compared to other manufacturers in a controlled environment has not been completed to date. In this paper, FilmTec™ SW30XLE elements are exposed together with equivalent commercially available membranes from other suppliers to a durability study to simulate long term operation and to determine the evolution of the membrane specifications over time. Particular focus is paid to the changes in salt rejection. Membrane durability plays a determining role in membrane replacement, which ultimately has a critical impact on the economics of any desalination plant. In this study, it was determined that after a number of cleanings, the salt passage increase over time of the membranes from other suppliers was close to 3.5 times larger than the value experienced by FilmTec™ membranes. More specifically, the salt passage increase experienced by FilmTec™ in the first study was 22%, while the membrane from another supplier showed a 73% increase; and in the second study, FilmTec™ had a salt passage increase of 43% while the membrane from the other manufacturer had a 140% salt passage increase. In a 100,000 m3/d desalination plant, this enhanced durability showed by FilmTec™ elements might represent a 5.5% cost of water decrease in the reverse osmosis stage, and total savings of 1.34 US ¢/m3 in the whole plant, which can be translated into savings of 488,000 USD/y. [ABSTRACT FROM AUTHOR]

Biofouling in reverse osmosis (RO) occurs when bacteria settle in the elements and start building a biofilm. This paper highlights the performance of a new generation of fouling-resistant RO element, the newly developed FilmTec™ SW30XFR-400/34 seawater fouling-resistant membrane element in terms of its biofouling resistance. Additionally, this paper presents a validation of the product at a realistic scenario: the Middle East Red Sea. The validation trials proved the robust performance that this new membrane element shows under harsh biofouling conditions. This membrane element is able to offer 34% lower pressure drop than previous generations with a stable performance in terms of normalized permeate flow and salt rejection. In the validation trials this feature led to a significant reduction of the chemical cleanings (CIP) caused by biofouling; more than 33% reduction of the annual CIP frequency. Additionally, thanks to the membrane chemistry robustness, one of the FilmTec™ brand essence attributes, the product is able to offer advantaged chemical resistance when chemical cleanings are performed. Under the same conditions, where an element from another membrane manufacturer is experiencing 85% increase in salt passage, FilmTec™ SW30XFR-400/34 shows stable performance. [ABSTRACT FROM AUTHOR]

Membrane distillation (MD) is a technology that is emerging as a viable alternative to traditional desalination techniques. This study assessed the feasibility of using the direct contact membrane distillation (DCMD) configuration of MD to desalinate saline water of different concentrations. We considered the feed supply of Arabian Gulf seawater (AGS) sand oil field-produced water and used polypropylene (PP) and polyvinylidene fluoride (PVDF) membranes to consider their performance under different operating conditions, such as channel depth, flow rate, temperature, feed concentration, etc. Their performance was evaluated by determining the water flux relative to the volume of salt rejection. The results showed that the permeate flux increased to 32.4 from 10.1 L/m²·h when the temperature was raised from 45°C to 75°C. Additionally, the permeate flux decreased to13.6 from 27.3 L/m²·h and the reduction in flux was around fifty percent when the concentration of sodium chloride (NaCl) in the feed solution was increased to 26% from 0%. The experimental results obtained using oil field-produced water were highly encouraging. The permeate flux was 11.5 and 12.5 L/m²·h at 80°C and 85°C, respectively. The results indicated the enormous potential of DCMD to treat hypersaline oil field-produced water, with an overall rejection of salts reaching above 99%. In comparison, PP membranes had a higher salt rejection rate but lower water flux, while PVDF membranes had a lower salt rejection rate but higher water flux. This paper presents, for the first time, the results of a laboratory-scale study conducted in the State of Kuwait to treat AGS and oil-produced water using DCMD technology under Kuwait's prevailing conditions. This study's findings will lay the groundwork for conducting pilot-scale studies on AGS and oil-produced water not only in the Middle East region but globally. [ABSTRACT FROM AUTHOR]

The low-temperature multi-effect distillation desalination (LT-MED) is an intriguing and advancing trend in the desalination process. However, calcium carbonate scale (CaCO3) can have lasting adverse consequences in heat-exchange tube in the LT-MED desalination system. It destructively affect the heat transfer and the water production efficiency. CaCO3 exhibit differences in the different environmental factors. Behaviour during operating pressure of LT-MED of calcium carbonate growth are unknown. This paper examines the influence of operation pressure on the precipitation of CaCO3 scale. It demonstrates that the amount of scaling is reduced under pressure. The least amount of CaCO3 scale is formed under the operation pressure of 60 kPa. The distribution probability of large particles of CaCO3 is greater under operation pressure. The operation pressure does not change the CaCO3 structure type. The structure of CaCO3 is still calcite. The molecular dynamics simulation is used to study the formation process of CaCO3 under different operation pressure. The formation mechanism about the CaCO3 scale under different operation pressure in LT-MED is further discussed. These data provide a link between CaCO3 behaviour during the experience of operation pressure. [ABSTRACT FROM AUTHOR]

The ever-increasing demand for producing drinking water from seawater triggered the development of competitive and advanced pretreatment for seawater reverse osmosis desalination plants. Ultrafiltration as a pretreatment has been optimized to compact design utilizing multi-capillary polyethersulfone (PES) membrane, whereas the DuPont™ Multibore™ membrane with seven capillaries has been employed in numerous large-scale applications with proven durability. The next generation of PES membranes has now been developed: a multi-bore PES membrane with 19 capillaries and an inner diameter of 0.7 mm, called DuPont™ Multibore™ PRO, within the recently launched DuPont™ IntegraTEC™ ultrafiltration portfolio. This new membrane geometry enables more membrane surface area per module, decreasing the number of required modules, hence decreasing the overall physical footprint for membrane modules by up to 17%. As a result, less material usage per m2 membrane surface area is needed to have a positive sustainability impact on module production, transportation, as well as end-of-life handling, leading to a significant overall reduction of the CO2 footprint. This study presents the results of the DuPont™ Multibore™ PRO being operated in a surface water and a seawater application. The surface water site is at a river in Germany. The seawater site is located at the Gulf in Qatar. This paper presents results of evaluation tests performed at these two locations with a multi-capillary ultrafiltration membrane. All results show comparable performance in terms of reversible fouling, chemical cleaning pattern, recovery, filtration flux and overall stable operation. At the surface water site, coagulant employed in the same concentration for the DuPont™ Multibore™ with 7 capillaries as for the DuPont™ Multibore™ PRO. Here, the feed water quality fluctuations in terms of turbidity are significantly higher compared to the seawater sites reflecting more stressful operating conditions. Additionally, the organic background level is higher with 5-8 mg/L dissolved oxygen carbon at the river water site. Polyaluminium chloride-based coagulation captures organic components which are then retained by the membranes. Due to the very unfavorable interactions with PES membrane surfaces, the fouling layer of coagulant is completely reversible during backwashes. [ABSTRACT FROM AUTHOR]

A common difficulty with water purification processes using reverse osmosis membranes is biofouling, a phenomenon in which bacteria grow within the apparatus, sometimes as biofilm inside the membrane element. Biofouling reduces the membrane permeability and generates a larger than desirable pressure drop across the membrane, which could also eventually mechanically compromise the membrane element integrity. In industrial scale systems, it is not possible to completely remove the grown biofilm from within the reverse osmosis membrane, even using harsh cleaning conditions. This paper highlights the performance of the FilmTec™ SW30XFR-400/34, the new generation seawater fouling resistant membrane elements. The elements were operated using Red Sea seawater, known for its high biofouling potential. The operational results highlighted the improvement obtained when replacing the heritage FilmTec™ SW30HRLE-400 with the improved SW30XFR-400/34. The results complied over more than 2 y of operation demonstrate that the pressure drop was reduced up to 40% while keeping a stable normalized permeate flow and increased salt rejection. [ABSTRACT FROM AUTHOR]

DuPont has recently released a new and improved digital tool to help plant operators normalize their data. This tool replaces the popular Excel-based data normalization tool that has been in use for over two decades. The new tool is user-friendly and easy to navigate. For a proper system performance assessment and optimization, ultrafiltration (UF) and reverse osmosis (RO) operating data normalization is vital in all systems which treat feed water with variable salinity and/or temperature. FT-Norm PRO (FilmTec™ Normalization of Membrane Systems) is a free online tool that makes the data normalization process simple yet robust enough to allow for effective monitoring of UF and RO systems. This tool helps plant operators explore how variations in feedwater temperature, salinity, or pump pressure can influence a membrane system's apparent productivity and rejection, making it more obvious when a real change in membrane performance occurs. This paper makes the audience to highlight the purpose and importance of data normalization in UF and RO systems, present the recently launched DuPont WaterApp and introduce the key tools to boost desalination plant performance through digital apps. Online tools assist users in quantifying their savings when using membranes with increased durability. Additionally, these tools can calculate the carbon footprint reduction achieved by implementing FilmTec™ dry seawater reverse osmosis membranes. Users can receive recommendations regarding the most suitable pre-treatment technology or membrane type and estimate the savings obtained using the novel DuPont™ B-Free™ pre-treatment technology to reduce biofouling in reverse osmosis systems. A reference plant, Alicante II Seawater Desalination Plant, will be used as an example to showcase the value of the digital apps. Thanks to the durability of the membranes and to correct operation and maintenance, this plant has been operating since 2008 without replacements. [ABSTRACT FROM AUTHOR]

The Episkopi integrated ultrafiltration (UF) and reverse osmosis (RO) seawater treatment plant is located in the district of Limassol (Cyprus) and is operated by MN Limassol Water Company (a consortium of Mekorot Development & Enterprise Ltd., Israel and Netcom Ltd., Cyprus). The plant was designed to produce 40,000 m3/d of permeate with a boron content below 0.5 mg/L and total dissolved solids content below 420 mg/L. The facility uses DuPont™ ultrafiltration (UF) and DuPont™ FilmTec™ reverse osmosis (RO) membranes as core desalination technology and DuPont™ AmberLite™ PWA10 boron selective resin as a polisher to help meet the strict boron quality requirements. The DuPont™ ultrafiltration system consists of 6 UF trains, each with 176 DuPont™ IntegraTEC™ ultrafiltration SFP-2880 modules. UF filtrate is stored in a tank. After the tank, the water passes through 100-micron strainers and feeds 5 seawater reverse osmosis trains. Each of these trains contains 120 pressure vessels with 8 elements. The pressure vessel configuration consists of an internally staged design with 4x FilmTec™ SW30XHR-440i and 4x FilmTec™ SW30HRLE-440i elements each. The system operates in permeate split mode. The rear portion of the RO permeate is sent to an ion exchange system for selective boron removal. The product water is mixed with the front permeate and is finally polished in a remineralization system. The plant was commissioned in 2012 and, after a period in standby, it was put in operation in 2014. During the 11 y of plant operation, the plant operated at variable capacity with some prolonged periods of shutdown. This paper will present the strategy and techniques that were implemented to preserve UF and RO elements during long-term shutdown periods and the performance of both UF and RO membranes during the 11-y period. Additionally, the ultrafiltration system is now experiencing partial renovation using high permeability IntegraTEC™ ultrafiltration SFP-2880 XP (with XP fibers). The benefits of using XP fibers will also be presented. [ABSTRACT FROM AUTHOR]

In order to overcome the problems of low control accuracy and long response time in traditional motion control methods of marine plant protection robot, this paper mainly studies the application of motion simulation in fuzzy control of marine plant protection robot. Firstly, the object motion simulation description algorithm of tree convex polyhedron is used to construct the working environment model of marine plant protection robot, and the marine plants are located by the model. Then, according to the positioning results, the motion equation of the marine plant protection robot is determined, and finally the fuzzy control of the marine plant protection robot is carried out. The experimental results show that, compared with the traditional method, this method has high control accuracy (up to 87%), short response time (up to 8.1 s), high signal strength, strong anti-interference ability and good application effect. It can be further popularized and applied. [ABSTRACT FROM AUTHOR]

The harmful algal bloom (red tides) (HAB) phenomenon is an issue for desalination facilities. This paper reviews the causes and impacts of HABs on desalination plants. Some HABs are linked to the creation of natural pollutants, dissolved oxygen depletion, and other negative consequences. Because desalination facilities are the principal source of freshwater for communities, agriculture, and industry for middle eastern arid nations, the disruption of plant operations by red tide poses a danger to the availability of drinkable water and can constitute an extraordinary HABs impact. Desalination plants are responsible for pollutants added to the Gulf seawater via outfall systems. Consequently, desalination projects must undergo an environmental impact assessment (EIA), considering accepted environmental characteristics and criteria. EIA assesses the potential effects on air, land, and sea water qualities, techniques to mitigate their impact. [ABSTRACT FROM AUTHOR]

The business sector of seawater desalination is composed of three major sectors in the MENA Region and worldwide: public sector, private sector and public–private partnership (PPP). Regardless of the desalination process wither it is based on thermal principles or reverses osmosis principles, the terotechnology had approved itself as a key tool in controlling the whole life-cycle of the process from asset management point of view. The terotechnology which is composed of seven major phases including specification, engineering, manufacturing, installation, commissioning, operation and maintenance and finally the asset obsoleteness or replacement, can be used as tools to govern the desalination business in all its three forms. The objective of this paper is to illustrate how to implement this in practice; how to govern the desalination business through terotechnology, and will be supported with real cases from the public sector, private sector and the PPP sector from independent water and power producers cases wither it is build-own-operate-transfer (BOOT or BOO). [ABSTRACT FROM AUTHOR]

The production of freshwater from seawater using solar energy is a sustainable process for resolving water scarcity problem. For increasing the utilization efficiency of solar energy, the recycle use of the condensation heat released from water vapor is an effective method. This paper reports a solar desalination of seawater using a compact multi-stage membrane apparatus, where the membrane part for desalinating seawater by evaporation and the freshwater collecting part for reusing the condensation heat were densely piled up. In the apparatus, heat transfer and water feeding were significantly improved to increase the performance of longer time operation. A poly(methyl methacrylate) sheet with low thermal conductivity was found to be more suitable than metal sheets with high thermal conductivity for the efficient recycle of the condensation heat from water vapor. The feeding of seawater by siphon mechanism, where seawater was flowed from top to bottom, suppressed the salt deposition to maintain the performance of the freshwater production, while the desalination performance was drastically deteriorated in the multi-stage apparatuses with capillary action for seawater feeding. Using the apparatus, the energy efficiency based on the energy from irradiated sunlight reached more than 200% by the repeated recoveries of the condensation heat. Freshwater was successfully produced from actual seawater with natural sunlight. [ABSTRACT FROM AUTHOR]

Aiming at the difficulty of sampling and monitoring the water quality of seawater aquaculture environment, this paper puts forward the design scheme of on-line monitoring system using unmanned ship as monitoring platform. Unmanned ship loading of water quality monitoring sensors and control equipment, the use of remote control or ways of working independently, with a single point of mobile instead of multipoint distribution measurement, realize synchronous acquisition of the mariculture environment more information. By modular design of the system, the collected water quality information, and to collect the geographic location information of wireless transmission first place machine, PC server receiving and processing data and the results stored in the database. This paper introduces the automatic control system of unmanned ship, presents the data transmission and storage process of the monitoring network, and introduces the water quality data processing of the upper computer. The scheme proved the feasibility through physical construction and experiment. [ABSTRACT FROM AUTHOR]

The self-boosting energy recovery device (SB-ERD) integrated with the booster pump function can reduce the power consumption of small and medium-sized seawater desalination systems. Nevertheless, for SB-ERD, the flow rate and pressure pulsation of HP brine and nonadjustable capacity are presented in the operation process, affecting its further application in seawater reverse osmosis (SWRO) systems. In this paper, the SB-ERD was modified to a miniaturized reciprocating-switcher energy recovery device (MRS-ERD). Then a SWRO experimental test platform equipped with MRS-ERD was built to evaluate operational performance. The experimental results show that the pressure pulsation amplitude of HP brine is maintained at 0.20 MPa, and the flow rate pulsation amplitude is kept only between 0.153 and 0.186 m³/h. At design capacity, the pressure pulsation ratio of HP brine is reduced by 2.41% compared with SB-ERD, and the flow rate pulsation ratio is only 1.5%, which is 4.05% lower than that of SB-ERD, revealing excellent operational stability. Furthermore, under 5.0 MPa and 80%-130% of the design capacity (12 m³/h), the MRS-ERD can run with a constant efficiency above 96.33% and a leakage ratio of 1.3%-2.7%, which is competitive in commercial products. Hence, MRS-ERD exhibits huge application prospects in small and medium-sized SWRO systems. [ABSTRACT FROM AUTHOR]

Renewable energies can benefit the water sector, reducing the cost and the environmental impact of water production. This paper presents a technical and economic assessment of a photovoltaic generation project to supply energy to a grid-connected seawater reverse osmosis (SWRO) desalination plant and of an associated battery energy storage system (BESS) using lithium-ion batteries. It examines the case study of the SWRO desalination plant on Porto Santo Island (Madeira, Portugal). The assessment is supplemented by a sensitivity analysis of several variables. The findings indicate that photovoltaic generation in desalination plants results in a lower levelized cost of energy (LCoE) and reduces the consumption of fossil fuel energy from the electrical grid. This can lead to lower desalinated water costs and greenhouse gas emissions. A feasible rated power range was identified for the photovoltaic plant in this case study, taking the internal rate of return, net present value, payback and LCoE into consideration. The results also point to a higher LCoE when a lithium-ion BESS is used. [ABSTRACT FROM AUTHOR]

Water scarcity is one key challenge mankind is facing. Seawater reverse osmosis desalination is a promising technology to solve it. However, further innovation which needs to go beyond product specifications is needed to decrease the total cost of water while at the same time, improving sustainability footprint. This paper describes a breakthrough step-change in innovation within the desalination industry: transitioning from wet-tested seawater reverse osmosis (SWRO) elements to dry-tested SWRO elements. This new concept has been achieved by DuPont thanks to a cumulation of significant breakthrough in reverse osmosis technology: continuous advancements in membrane chemistry, automated precision manufacturing, single source manufacturing, a robust quality control, and enhancements in testing methods. Dry SWRO elements offer significant advantages over wet elements, given the requirement to monitor and eventually replace preservation solutions for wet membranes. Dry membranes enable longer storage times, lower labor costs and easier longterm warehouse planning. Dry membranes are safer to install due to a 4 kg weight reduction and are easier to handle. From the sustainability point of view, the dry-test SW concept also brings plenty of benefits: (1) Reduces fresh-water consumption as no wet testing is required; (2) Eliminates wastewater generated during wet testing; (3) Significantly reduces energy consumption by skipping wet testing; and (4) the lower membrane weight will significantly decrease the environmental footprint of dry elements, reducing by up to 20% the CO2 generation during transportation. In a large desalination installation supplied with dry SWRO elements, the greenhouse gas emissions reduction equals those generated by a passenger vehicle driving more than 500,000 km. Additionally, dry SWRO elements offer the same water productivity and permeate quality as wet elements. [ABSTRACT FROM AUTHOR]

Water scarcity is a great challenge that has always stimulated research interests to find efficient ways for the production of pure water. In this context, reverse osmosis is considered as the most important and optimized membrane desalination process that currently dominates the desalination market to help meet the growing water needs, specifically in water-stressed countries. This paper reviews the evolution of desalination in Morocco and presents three case studies of desalination plants: Laayoune, Boujdour (seawater desalination) and Khénifra (the first experience of demineralization of brackish surface water in Morocco). Also, the challenges encountered during the operation of the desalination plant. [ABSTRACT FROM AUTHOR]

Low-temperature thermal desalination (LTTD) process uses naturally available ocean thermal gradient that is environmentally friendly with the advantage of minimum maintenance. The process deals with evaporating the warmer surface seawater at low pressures and condensing the resultant vapour using deep sea cold water available at about 350-400 m below sea level. Ministry of Earth Sciences (MoES) - National Institute of Ocean Technology (NIOT) has established LTTD plants with fresh water generation capacity of 1 Lakh Liters Per Day (LLPD) at Agatti, Minicoy and Kavaratti Islands and those plants were being run by UT administration using local manpower. The construction works are in progress for setting up the similar plants in six more islands with a capacity of 1.5 LLPD. In the view of rapidly growing population, tourism activities and to meet the long term needs in remote islands, the design studies were carried out for scaled-up LTTD plants, from 1.5 to 7 LLPD. The studies presented in this paper, facilitate us to instantly identify the size of major components and determine the preliminary cost for implementation for any capacity of the plant up to 7 LLPD, which ultimately results in significant reduction in design lead time. [ABSTRACT FROM AUTHOR]

Solar-driven seawater desalination has emerged as a promising strategy to solve the global water crisis with green energy. In this paper, an ultra-black nylon flocking photothermal material was developed and applied as a solar evaporator. The theoretical analysis of high-efficiency interfacial evaporation was introduced. The performance of the evaporator in terms of evaporation rate and salt resistance was evaluated through the experimental verification method. With the introduction of the ultra-black nylon flocking material, the evaporation efficiency increased by 76.06% for seawater desalination. In the long-term stability test, the average evaporation rate was above 1.20 kg/m2 h. Evaporation and condensation experiments were further carried out using a small solar distiller. The results showed that installing ultra-black nylon flocking material in traditional disc-type solar distiller could increase the water production from the original 2.8 to 7.76 kg/m2 d. Without the condensation chamber, the amount of vapor evaporating out to the ambient environment was up to 10.24 kg/m2 d. Thus, facilitating the steam condensation while improving the evaporation efficiency is of great significance to the broad application of solar desalination. [ABSTRACT FROM AUTHOR]

Maximum permissible concentrations of inorganic elements, including toxic constituents (heavy metals), in drinking water, are established by the World Health Organization (WHO), EU Council Directive 98/83/EC of 3 November 1998, and relevant national regulations. The paper presents an assessment of reverse osmosis SW30 membranes for simultaneous removal of boron, copper, and lithium from two high-mineralized water. The experiments conducted allowed to gain removal up to the following values (retention coefficients): boron (30% and 8%), copper (89% and 69%), and lithium (39% and 8%), in permeates. Despite the quite promising removal ratios gained for copper and lithium, the value of reduction of mineralization, boron, and some of the major ions was insufficient and their concentration values exceeded the parametric value introduced in the mentioned Directive. In concentrates with these three parameters, negligible increases in concentrations were observed. The research work carried out provided that the treatment of high-mineralized water with increased content of microelements with the use of a one-step reverse osmosis system is not an effective enough solution. Due to the unsatisfactory boron removal and mineralization reduction being gained, further studies should be carried out to improve the efficiency of removal of these components, for example, the use of a multistage desalination process or secondary treatment. [ABSTRACT FROM AUTHOR]

The paper deals with the work of the single-stage vacuum fresh water plant usually used on board cargo ships, namely with the influence of the thermodynamics process and of the technological arrangement on the performances. The distillation method has been well known since the ancient civilization, but there is still room for the improvement of the process depending on the selected criterion. Furthermore, the arrangement of the plant, including all control and regulation elements, has an impact on the process running and, after all, on the quality and quantity of the generated distillate as well as on the price of the installation. As a conclusion, a simple mathematical analysis has pointed to the key parameters that have to be monitored during the work as well as to the possible optimal control system, as it has been proved by simulating the work and registering the changes in the stated parameters during variable working conditions. The result of the paper could lead to a simpler and cheaper governing system, to the better quality of the distillate and more operating hours of the equipment. [ABSTRACT FROM AUTHOR]

In order to reduce the energy consumption of seawater desalination, this paper proposes an operation test method of seawater desalination device based on information fusion. Based on the theoretical analysis and calculation of energy consumption of seawater desalination system, the influences of feed water salinity, recovery rate, energy recovery device, high-pressure water pump and other factors on energy consumption and water quality of seawater desalination system are analyzed. An energy-saving integrated desalination process with differential pressure exchange energy recovery device is proposed, and a differential pressure exchange energy source matching with a small desalination system is independently developed. The results show that the produced water quality of the desalination device basically meets the design requirements, and the energy consumption of the motor and pump is only 2.0 kWh/m3 without considering the loss of the motor and pump, which can greatly reduce the water production energy consumption of the system, and has a certain application value. [ABSTRACT FROM AUTHOR]

In the optic of water production with pollution reduction, we treat, in this paper, humidification-dehumidification desalination process, called Seawater Greenhouse (SWGH), using an agricultural greenhouse with solar collectors as a roof, combining irrigation and desalination functions by a low-temperature distillation method. Indeed, two SWGH models were achieved, the first one on a block diagram environment program and the second one on an equations solver program. Thus, we are going to present and analyze the simulation results, provided by these models, made for different parameters and locations, in order to estimate the outlet freshwater amount depending on the site choice. As a conclusion, we will be able to draw a choice technique of the most beneficial environmental, meteorological, and geographic place of SWGH implantation, where a great producible is reachable. And thanks to this technique we have confirmed that Morocco can, technically, be very beneficial for the implantation of this desalination process, given its perfectly adapted climate with a producible exceeding 1,000 L of freshwater per day. [ABSTRACT FROM AUTHOR]

In a previous paper, we proposed the construction of a new seawater intake in order to reduce the temperature range of the feed water, and a pilot plant for testing three types of low energy and high rejection membranes comparing performance and quality in a seawater reverse osmosis (SWRO) plant in the southeast of Spain. The results of the elements are shown. The conclusions of the study may serve as a tool for the decision‐making processes related to membrane replacement and retrofit projects whose designs were based on new high-efficiency membrane configurations in the plant. The selection of the element will be determined regarding the performance and energy costs of the pilot test. [ABSTRACT FROM AUTHOR]

The case study of the Canary Islands (Spain) considered in this paper involves the historical problem of resolving the demand for freshwater. After many years, the focus in the islands turned towards seawater desalination processes to provide safe water for, above all, its citizens, agriculture, and tourism. Due to the high demand for freshwater, the Canary Islands have been a world pioneer in desalination issues, improving the techniques and materials used. While several desalination technologies are available, today the most used worldwide is reverse osmosis. The major drawback of desalination is the high energy cost that the process requires. To this can be added the peculiarities of the electricity generation system in the Canary Islands, which generates more emissions per unit of energy produced compared with the system in mainland Spain. In this study, we selected a desalination plant located on the island of Tenerife, specifically in the municipality of Granadilla de Abona and, after determining its technical characteristics, calculated its ecological footprint. For this, we performed various calculations, including the carbon fixing capacity of forests in the Canary Islands (expressed per hectare) and the total amount of emissions produced in the generation of energy to feed the desalination plant. [ABSTRACT FROM AUTHOR]

The paper presents a numerical study to investigate the solar membrane distillation (SMD) system for seawater desalination using solar energy. The SMD system includes both flat plate collectors and photovoltaic panels. Therefore, the photovoltaic system is used to power electrically the pumps and sensors. The present model has good compatibility of no more than 5% with the experimental air-gap membrane distillation (AGMD) system. It was found that the solar AGMD system is used for the production of 3–5 L/h of distilled water flow. In addition, the energy needed is calculated for the pumps and replaced by two photovoltaic panels, each one has an area of 1.6 m2 using an energy storage battery (12 V, 200 Ah). Besides, the brine that contains the high salt concentration is completely dispensed with this process. Therefore, the energy efficiency of the AGMD module and the collector efficiency values reach 68% and 74% respectively. The solar AGMD system will be studied using TRNSYS and PVGIS programs on different days throughout the year in Ain Temouchent weather, Algeria. [ABSTRACT FROM AUTHOR]

The objective of this paper is to present a methodology to predict vacuum load theoretically and to compare those results with the experimental values for validation especially the non-condensable gas load and escape water vapour load. The primary objective of this paper is to find out the accumulated effect of non-condensable gases on the vacuum load of low-temperature thermal desalination (LTTD) plant. Suggestions to control the NC gas and escape vapour load on the LTTD process were also discussed in this paper. Determination of an exact amount of vacuum load for the plant is significant, since vacuum system alone shares about 31% of total energy demand of the LTTD plant. Load contribution given by the gas mixtures such as escape water vapour, non-condensable gas and air leak in to the system was experimentally measured by conducting suitable experiments in a running plant of 100 m3/d capacity located in the Island of Agatti, UT Lakshadweep group of Islands, India. Study at Kavaratti plant of same capacity showed that the escape vapour rate was equivalent to 0.3% of the freshwater generation rate of the plant, which was used as an input value for Agatti vacuum load calculation for escape vapour rate. On comparison of the experimental results of non-condensable gas release rate of Agatti plant with the published data and predicted values using methodology, an agreement up to 16 and 7.7% was obtained, respectively, under the same operating conditions. Also, an agreement up to 15% was obtained between the experimental results of Agatti plant with that of observed results of Kavaratti for water vapour escape rate from the main process condenser. It was reported in the literature that for MED desalination system, the extraction of vapour from the evaporator unit linked with a removal of 10–20 units of vapour corresponded to every unit mass of NC gases. But in the present study, for the LTTD process, it was measured that the accumulated effect of NC gases for every unit mass resulted in extraction of 1.6 unit mass of vapour (approx) from the process condenser. This low value could be due to low operating temperature range of LTTD process and use of low-temperature deep-sea cooling water from the ocean in the condenser tubes. From calculation, it was noticed that decrease in molecular weight of gas increased the volumetric vacuum load for the same operating conditions and gas mass flow rates. Also, it was observed that the parameters such as operating pressure, duct loss, mass flow rate of feed water influence the total vacuum load of LTTD plant. [ABSTRACT FROM PUBLISHER]

For a consistent and reliable ultrafiltration (UF) membrane operation, the membrane flux level has always been determined conservatively so that fouling rate is controllable, and therefore, chemical cleaning requirements are minimized. A better solution is to prevent the fouling to happen in the first place by modifying the surface properties of the membrane materials. This paper presents novel approaches to improve the fouling-propensity performance of existing UF membranes based on polyethersulfone. More hydrophilic membranes and anti-adhesive membranes were developed by using various novel copolymers as base membrane materials or as an additive in the spinning process. Incorporating these copolymers, improved Multibore® fibers were produced and validated in multiple pilot trials for various applications, namely surface and wastewater purification and seawater reverse osmosis pretreatment for desalination. The paper demonstrates that, for each application, a reduced fouling propensity performance was achieved, allowing the fibers to be operated at a substantially higher flux of up to 30%. This study underscores the importance of chemistry in obtaining low-fouling and high-performance UF membranes by modifying their surface properties. [ABSTRACT FROM PUBLISHER]

Low-temperature thermal desalination is a process which involves evaporation of warm surface sea water at 28–29˚C inside an evaporator which is maintained at a subatmospheric pressure of around 24–27 mbar [abs] and the resultant vapour is condensed in the condenser using deep-sea cooling water (12–13˚C) drawn from a depth of around 350–400 m (approx). Designed heat load and overall heat transfer co-efficient of the condenser are around 3.4 MW and 1,790 W/m² K, respectively, for an inside tube cooling water velocity of 1.25 m/s. The primary objective of this paper is to experimentally study the performance of a shell and tube condenser and to compare it with the HTRI 6.0 results as well as Kern method for the same operating parameters. A comparative study showed that the predicted results of HTRI were in good agreement with experimental values as well as with Kern method. After the comparative study, the reasons for variation in results were identified, reviewed and discussed. Experimental study revealed that the deviation of actual inlet conditions from the design conditions at the plant site greatly influences the condenser performance. It was observed from data analysis that the effect of fouling of deep-sea cooling water on the condenser performance is insignificant. Uncertainty analysis also has been carried out and presented in this paper. [ABSTRACT FROM AUTHOR]

Water security in Qatar is of main concern. Low water pricing in Qatar does reflect the real value of water. The high cost of desalted seawater (DW) calculated in this paper calls for the use of more energy efficient desalting system such as the SWRO system in place of the multistage flash (MSF) and multieffect thermal vapor compression (METVC) methods presently used. Both MSF and METVC use thermal energy of about 270 kJ/m3and pumping energy of 2–4 kWh/m3. In this paper, the mechanical energy equivalent to the thermal energy supplied to the MSF (or METVC) systems is calculated. When added to the pumping energy, it gives the specific consumed energy of more than 20 kWh/m3, compared to 4–5 kWh/m3for SWRO system. Qatar’s ground water (GW) is overexploited, depleted, and quality deteriorated, and thus the demand for DW is on the rise, with the more financial burden. Moreover, DW productions mean more air and marine environment deterioration. The water subsidization by the government should be reviewed, and water demand management should be applied. Wastewater should be treated for reuse to decrease the demand on both GW and DW. The calculated costs of DW at different natural gas price are calculated, and compared with the underestimated cost reported by the government. [ABSTRACT FROM PUBLISHER]

Seawater reverse osmosis (SWRO) is the most cost-effective, practical, and widely used desalting system. Its energy consumption, for Arabian Gulf seawater conditions is in the range of 5–6 kWh/m3. These are less than 1/3 of the equivalent mechanical energy of the thermal desalination systems presently used in Qatar. Besides, these thermal systems consume 2–4 kWh/m3for pumping. Therefore, using SWRO system in Qatar can save up to 75% of the desalination energy cost. For Qatar, current desalting water production using thermal methods is 480 Mm3/year at $0.1–1.2/kWh energy price; the energy cost is at least one Billion US dollars per annum. A SWRO pilot plant is to be built in Qatar prior to building a full size desalting plant (DP) in order to determine site-specific treatment guidelines and to provide a full range of performance information to be used in the design of a full-scale plant. The pilot plant will be tested when the feedwater quality is good, and when there are major storm events or algae blooms exist. Red tide events in 2008–2009 forced many DPs in Gulf Co-operation Countries area to shut down. This paper reviews the SWRO pretreatment process, which depends on local conditions and is the main factor affecting the SWRO reliability. These include the extensively used conventional pretreatment of coagulation–flocculation and granular media filtration (GMF). This is almost necessary for open sea intake. Sever red tide blooms, when occur, cause clogging of GMF, resulted in biological and organic foulants on SWRO membranes, and even DP shut down. So, low-pressure membranes such as ultrafiltration (UF) or microfiltration (MF) can replace or integrated with GMF. Since flotation is more robust than sedimentation (used in GMF) in dealing with high concentration of suspended matter, dissolved air flotation is started to be used as pretreatment. Since it is a new method that met success in several plants, it thoroughly reviewed in this paper when integrated with GMF or membrane treatment. Additionally, the expensive pretreatment with UF and MF is discussed with given examples. Preliminary experimentation with SWRO pretreatment in Qatar was presented. Moreover, energy recovery devices to be used with the pilot SWRO are discussed. Membranes configuration and the equipment to be included are also outlined. [ABSTRACT FROM PUBLISHER]

In this paper, exergoeconomic and exergoenvironmental analyses of a solar vacuum membrane distillation (VMD) desalination system were performed to evaluate the cost of exergy destruction and the environmental impact of each component of the desalination system. The analysis permits the identification and evaluation of inefficiencies in the plant as well as the determination of the most environmental friendly process components and opportunities for design improvements. The results showed that the solar collector has the largest irreversibility and cost of exergy destruction. Therefore, it is a very important component for improving solar VMD plant performance. In addition, it will be profitable to reduce exergy losses in the membrane module even at the expense of increased investment costs since the dominant factor in the total cost rate for this component is the cost of exergy destruction. Whereas, it would be advantageous to reduce capital costs in the condenser since it has a relatively high exergoeconomic performance. On the other hand, exergoeconomic factor and exergy efficiency for the heat exchanger are found to be 49.02% and 96.59%, respectively, indicating that the exergy and exergoeconomic performance of this component is satisfactory. Finally, the results revealed that the largest potential for reducing the overall environmental impact of the solar VMD system is associated with the solar collector, the membrane module, the condenser, and the heat exchanger. [ABSTRACT FROM AUTHOR]

Low temperature thermal desalination process uses an unique technology in which the surface seawater (28°C-29°C) is flash evaporated inside a vacuum flash chamber maintained at a pressure of 25-27 mbar (abs) and resultant vapour is condensed in the condenser using deep-sea cooling water at 12°C-13°C drawn approximately from 350 to 400 m depth. The objective of the present paper is to discuss the effort that has been made to improve the deaeration process using a row of tube bundles with different pitch ratios such as 1.25, 1.5, 2, and 3 which were placed in the entry seawater passage pipeline to the deaerator. Tube bundle is expected to create disturbance in the water and improve the deaeration of dissolved gases (non-condensable; NC). Influence of these tube bundles on the assessment of NC gases release rate is discussed in the present work. A new methodology with two equation model has been developed to determine the deaeration efficiency based on the experimental study is presented in this work. It is observed from the study that the amount of NC gases released from the seawater by bundles influences the escape rate of water vapour from the main condenser. A maximum of 86.4% deaeration efficiency is observed from the experiments. [ABSTRACT FROM AUTHOR]

Reverse osmosis (RO) has developed into one of the most commonly applied technologies for the reduction of the salt content of a feed stream. While it is a widely applied purification process, the market is continuously challenging suppliers for innovation to increase the economics and sustainability. This paper will review and analyse the field performance of Dow FILMTEC™ new high-flow/low-energy seawater reverse osmosis elements—SEAMAXX™. This new seawater RO membrane, which has the highest permeability currently available, is based on innovation related to membrane chemistry. SEAMAXX can be used to increase the recovery of an existing system or to decrease the energy consumption. In either case, the final cost of water is estimated to be between 10 and 15% lower compared to previously available state of the art RO elements. This paper will focus on three different cases studies where the expected performance of SEAMAXX has been validated. Two of these cases correspond to small-size and medium-size pilot trials completed at the Water Technology Center of Dow Water and Process Solutions in Tarragona, Spain. The third experience is a commercial installation which has been in operation with SEAMAXX elements since May 2013. In this particular facility, a retrofit of the RO system was undertaken such that existing 11-year-old FILMTEC membranes were replaced with next generation SWRO membranes. This commercial installation, located in the Canary Islands (Spain) treats the seawater (Atlantic Ocean) well to produce drinking water. In this third case, the performance of the desalination plant will be compared with the performance of the previous elements as well as with the predicted or expected performance of SEAMAXX according to ROSA™(reverse osmosis system analysis) simulation software and DOW™FT-NORM normalization tool. Rejection of dissolved salts and in particular, rejection of Boron has been carefully monitored by regular analysis in Dow’s R&D Lab and in external certified laboratories. After almost one year in operation, the performance of SEAMAXX has been validated through different seasons and different sets of operating conditions, confirming the expected savings in energy consumption. [ABSTRACT FROM AUTHOR]

The removal of dissolved gases such as oxygen from seawater is one of the primary process applied in desalination industries. The effective degasification of dissolved gases remains a challenge in the desalination industry due to several reasons such as removal efficiency, performance, gas selectivity, and others. This paper describes the fabrication, characterization, and degasification performance study of carbon nanotube/polyvinyl chloride (CNT/PVC) nanocomposite membranes. The CNT/PVC nanocomposite membranes were fabricated by immersion precipitation method at 0.01, 0.25, and 0.5 wt.% CNT concentrations in the casting solution. The physicochemical properties of fabricated membranes were studied by Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), contact angle (CA), water uptake, and liquid entry pressure (LEP). The FTIR analysis confirmed the proper dispersion of CNT throughout the membrane. The values of CA, water uptake, and LEP decreased with the increase of CNT concentration in the membrane matrix. The FESEM and AFM studies showed an increase in macrovoid structure and a decrease in surface roughness with increased CNT concentration. The newly fabricated membranes showed excellent degasification performance under the prevalent conditions of the desalination process. [ABSTRACT FROM AUTHOR]

Seawater reverse osmosis (SWRO) has become an important method to solve the water shortage. In order to reduce energy consumption, the energy recovery device is widely used in the SWRO system. In this paper, an electro-hydraulic system is proposed to simultaneously realize raw seawater pressurization and energy recovery. The hydraulic cylinder and seawater cylinder are rigidly connected, and the pressurization and output flow of raw seawater is controlled by coordinating the motion state of the two hydraulic cylinders. The mathematical model of the system was established, and the feasibility and performance of the electro-hydraulic proportional control based pressurization and energy recovery system were verified by means of simulation and experiment. The results show that the pressure and flow fluctuation of raw seawater is small, and the energy consumption of produced water reaches 2.76 kWh/m3, which is lower than that of conventional seawater desalination equipment. [ABSTRACT FROM AUTHOR]

In order to reduce scaling in a multistage flash (MSF) desalination plant, the brine reject can be diluted using forward osmosis (FO) before recycling. In this FO process, the brine is used as the draw solution (DS) and seawater is used as the feed solution (FS). However, the FO process suffers from low water flux owing to membrane fouling. The water flux in FO can be enhanced by reducing the foulant concentration in the FO feed solution (FS). Thus, in this paper seawater, multimedia sand filtered seawater, and ultrafiltrated seawater is being used as feed solution for the FO process. The flowrate of the feed solution was kept constant at 2.0 L/min. However, the flowrate of the draw solution (DS) were tested at 2.0 and 0.8 L/min. When the flowrate of the DS was 0.8 L/min, the highest initial flux of 44.1 L/m2 h were obtained using ultrafiltrated seawater as FS. After the initial run, the membrane was cleaned and during the second run, 83% of the initial flux was recovered using the ultrafiltrated seawater as FS. For ultrafiltrated seawater, the water recovery rate and specific energy consumption was 36.2% and 0.065 kWh/m3, respectively. [ABSTRACT FROM AUTHOR]

Freshwater production from seawater using solar energy is now an essential technology as a countermeasure of global water shortage. We have previously reported a seawater desalination process by membrane permeation of the water. In this process, seawater put on dye modified hydrophobic membrane is vaporized by irradiated light with the modified dyes. The water vapor thus formed penetrates through the membrane, and desalinated water is recovered under the membrane. This paper reports our latest approaches to enhance the performance of the solar desalination of seawater by the membrane permeation. Solvent black 5 (SB5) that absorbs the wide range of sunlight including near-infrared light was effective as a dye used for the desalination process. For scaling-up this process, dye modified membranes were tightly sandwiched between two flanges for holding a large volume of seawater on the membrane. The two-ply membrane system consisting of SB5 modified cellulose membrane on non-modified polytetrafluoroethylene membrane was found to be the best combination for freshwater production from seawater by the irradiation of simulated sunlight. Desalination of actual seawater using natural sunlight was also achieved by the two-ply membrane system. These results indicated that the freshwater production by the solar desalination of seawater with the membrane permeation is a practical countermeasure for global water shortage. [ABSTRACT FROM AUTHOR]

SWCC DTRI adopted a highly ambitious research program in which nanofiltration (NF) membranes operated on pretreated seawater to improve its scaling and fouling potential. NF membrane seawater pretreatment was introduced commercially at SWCC Umm Lujj SWRO plant, where NF and SWRO processes operated at 65% and 50% recovery, respectively, with an overall recovery of 32.5%. Therefore, this paper presents (Part-II) of this project, which deals with NF product as a superior RO feed with the main objective of increasing the water production at Umm Lujj NF/SWRO plant and improve its overall economics. In order to achieve the same, several approaches were adopted which includes long-term performance evaluation of NF membrane seawater pretreatment, SWRO and BWRO processes at recoveries of 90%, 52% and 92%, respectively. The results revealed that Umm Lujj NF/SWRO plant overall recovery can be increased from 32.5% to 44%. [ABSTRACT FROM AUTHOR]

To cope with the large energy consumption in the most commercial desalination processes, along with the growing concern about climatic change resulting in CO2 emission, much effort has been made since almost four decades to use renewable energies to run desalination units. Among the numerous desalination processes driven by renewable energies, the seawater greenhouse received much attention for decentralized production of fresh water. The paper deals with an innovative hybrid approach of seawater desalination that has been explored. It combines a seawater greenhouse (SWGH) with a solar pond to produce more fresh water. Furthermore, it enables a better management of brine, which represents a major issue for all desalination processes. Indeed, the rejected brine of the SWGH will be recycled, by using it in a solar pond as a heat storage plant and a heat source to warm the air to more or less than 70°C at the inlet of the second evaporator of the SWGH. The process scheme and the mathematical and software models of both the classical SWGH and of its hybridization with a solar pond are presented. The calculations show that the fresh water production rate of the new SWGH concept is more than five times higher than of the classical SWGH one. Simulations on different Moroccan sites were realized as a case study, to estimate the added value of the new SWGH model and, at the same time, to compare its profitability in these implantation locations. [ABSTRACT FROM AUTHOR]

Multistage flash (MSF) and reverse osmosis (RO) are the two major desalination technologies currently serving the needs of freshwater in Kuwait. MSF is energy intensive and suffer from low water recovery, while RO desire energy to fulfil its pressure requirement for the process. Thus, globally the scientists are focusing on the innovative desalination technologies which could be operated at low cost and environmentally friendly. In this regard, forward osmosis (FO) is one such emerging technology which can be operated under “Non-Pressure” requirement conditions to reduce the energy/cost of the desalination process. The principle of FO involves flow of the pure water across the semipermeable membrane by maintaining an osmotic pressure gradient between the feed solution (low concentration solution) and draw solution (high concentration solution). Related to this concept, a project was conducted at Kuwait Institute for Scientific Research to fabricate potential and fouling control membranes for the FO desalination. The aim of this paper is to present the important outcomes of the project in fabricating different types of membranes and results related to the high-performance thin film nanocomposite (TFN) membranes obtained in the project compared with commercial FO membranes. The TFN membrane with 0.05 wt.% nanoparticle composition resulted in high flux of vs. the commercial CTA membrane. Therefore, this work concluded that a suitable selection of nanoparticles and their proper modification is essential to fabricate potential membranes for FO application. Further, a nano-based FO membrane showed a potential application in FO desalination compared with commercial FO membranes. [ABSTRACT FROM AUTHOR]

Multistage flash (MSF) and reverse osmosis (RO) are the two major desalination technologies currently serving the needs of freshwater in Kuwait. MSF is energy intensive and suffer from low water recovery, while RO desire energy to fulfil its pressure requirement for the process. Thus, globally the scientists are focusing on the innovative desalination technologies which could be operated at low cost and environmentally friendly. In this regard, forward osmosis (FO) is one such emerging technology which can be operated under “Non-Pressure” requirement conditions to reduce the energy/cost of the desalination process. The principle of FO involves flow of the pure water across the semipermeable membrane by maintaining an osmotic pressure gradient between the feed solution (low concentration solution) and draw solution (high concentration solution). Related to this concept, a project was conducted at Kuwait Institute for Scientific Research to fabricate potential and fouling control membranes for the FO desalination. The aim of this paper is to present the important outcomes of the project in fabricating different types of membranes and results related to the high-performance thin film nanocomposite (TFN) membranes obtained in the project compared with commercial FO membranes. The TFN membrane with 0.05 wt.% nanoparticle composition resulted in high flux of vs. the commercial CTA membrane. Therefore, this work concluded that a suitable selection of nanoparticles and their proper modification is essential to fabricate potential membranes for FO application. Further, a nano-based FO membrane showed a potential application in FO desalination compared with commercial FO membranes. [ABSTRACT FROM AUTHOR]

Quality of product water by seawater reverse osmosis (SWRO) desalination has an impact on consumers' health. In this paper, data of product water were obtained from three full-scale SWRO desalination plants for the benefit of a drinking-water supply system in China. Qualities of this product water were analyzed by 103 items. Moreover, challenges and future research needs of the product water by SWRO desalination were pointed out. The results showed that inorganic chemicals and disinfection by-products accounted for about 42% and 33% of the total measured indicators, respectively. [ABSTRACT FROM AUTHOR]

Fouling is an essential obstacle in seawater treatment. This paper studies the effects of temperature and salinity on fouling characteristics, in particular to reveal scaling crystals that affect the deposition amount with the technique of static deposition in hypersaline seawater. The results show that the deposition amount on the titanium tube surface decreases with increasing salinity at a temperature of 80°C, achieving the highest value at the salinity of 8%. In comparison with that at 80°C, the change trend in deposition amount is different at the temperature of 90°C achieving the largest value at the salinity of 12%. The major composition on the metallic surface is Mg(OH)2 at diverse working conditions. Moreover, CaSO4 and CaCO3 crystals are suspended in the beaker, while bulk crystals eventually deposit at the bottom of the beaker. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to present an overview of the design for both the full-scale and pilot-scale seawater reverse osmosis (RO) pre-treatment plant comprising dissolved air flotation (DAF) and dual-media filtration (DMF) proposed and operating, respectively, at the Ras Al Khair site in Saudi Arabia. This paper will deal with the design implications for a highrate DAF and DMF plant, rated at a net loading of 30m/h and up to 6.5 m/h, respectively, processing a proposed feed flow of approximately 1,010 Ml/d, and then how to replicate this using a pilot plant. In addition, how water conditions such as high salinity and temperature and the physical characteristics of the plant impact the process design. The basic water chemistry requirements and the physics when applying dissolved air will be discussed. In the latter case this involves both the dissolving and the subsequent efficient release as fine micro-bubbles of the air, to ensure that the required level of clarification is achieved ahead of filtration and that an SDI15 of <4 is consistently delivered to the RO plant. [ABSTRACT FROM AUTHOR]

Reverse osmosis (RO) is a widely accepted and applied process for the purification of a variety of raw water sources, especially when there is a need for removing the bulk of the dissolved salts and other impurities present in the feed streams. Since its first applications and references, the technology has progressively been refined and improved, up to the current mature status, where, even if innovations are still to come, a solid base frame exists already. This paper will review and analyze long-term operation data from medium and large-size projects, including two different seawater desalination plants examples. It will focus on the long-term stable and reliable performances of DOW FILMTEC™ RO elements, by comparing the expected performance to the current operation data, with special emphasis on the long life of elements, and thus low replacement rates. These two installations are of particular interest given the time they have been successfully producing the required amount of drinking water. The paper will also evaluate the existing plant designs and contrast them to plant design modifications that would have been applied if those installations were designed with current membrane element technology. [ABSTRACT FROM AUTHOR]

Humidification dehumidification processes have been extensively introduced to the field of desalination. In this paper, a water-heated humidification dehumidification desalination system (HDDS), with open-air and semi-closed seawater water configurations, is proposed to achieve the waste heat recovery. After establishing the energetic and entropic equations of the humidification dehumidification desalination system, the corresponding analysis is accomplished. Furthermore, the dependence of the desalination performance, including the water production and relevant thermal efficiency, to the effectiveness, and cycle ratio are focused. The simulation results show the peak values of water production and gained-output-ratio (GOR) emerge at the balance condition of the humidifier. Nevertheless, due to the acquisition of the negative entropy generation rate, the actual values of water production and GOR are found as 104.64 kg h-1 and 1.98. Based on the parametric analysis, it is found that a lower humidification effectiveness is beneficial to raise the actual desalination performance, while the HDDS performance will be elevated after the increase of the dehumidification effectiveness. Furthermore, the improvement of energy conversion for the current configuration is also proved in response to recover partial brine into the feed seawater. [ABSTRACT FROM AUTHOR]