Search

The insufficiency of water resources and the need for potable water constitute a major concern for many countries, especially Morocco, which has experienced a significant increase in water demand due to population growth, economic development, and climatic conditions. To address this issue, Morocco has initiated an ambitious program to establish seawater desalination plants using reverse osmosis technology in semi-arid areas. This study addresses the pressing concern of ensuring the reliability and quality of desalinated water in the Al Hoceima seawater desalination plant, a vital initiative by Morocco to combat water scarcity in semi-arid regions. Employing the Failure Modes, Effects, and Criticality Analysis (FMECA) method, a comprehensive analysis was conducted to identify potential malfunctions compromising water quality and process reliability. Failures were ranked in descending order of criticality, and cumulative criticality was calculated to prioritize improvement actions. The Pareto diagram generated from this analysis helped identify critical failures in the studied system that require prioritized improvement actions. Notably, it was observed that 80% of the criticality corresponded to half of the failures. Consequently, an improvement plan should be developed for 12 out of the 24 predetermined failure modes, focusing on those identified as most critical. Subsequently, an improvement plan was formulated, integrating short-term corrective actions such as optimizing cleaning protocols and medium to long-term preventive measures such as upgrading equipment and implementing redundancy systems. This study contributes novel insights into enhancing process reliability in seawater desalination plants, particularly in semi-arid regions like Morocco, by providing a systematic approach to identify and prioritize potential failures, ensuring the sustainable provision of potable water. [ABSTRACT FROM AUTHOR]

Seawater bittern is obtained as a by-product of the solar salt industry or saline water conversion plants. This product is rich in Mg2+, Cl−, SO42-, K+, as well as Na+ ions. In the present work, we investigated the chemical products of seawater extraction during the conventional evaporation-crystallization process, when plasma is applied over the solution. In the present work, we investigated the chemical products of seawater extraction during the conventional evaporation-crystallization process, when plasma is applied over the solution. Crystal films were formed on the surface, both in the region surrounding the plasma application and far regions. However, the films in the vicinity of the discharge had grain sizes up to 97% smaller than those of natural evaporation. We also observed that the region close to the plasma produces salt with higher Mg/Na and K/Na ratios than in the sedimented salts, indicating greater selectivity of the plasma process. This study adds to the growing body of research that indicates plasma as energy source in the desalination or separation processes. [ABSTRACT FROM AUTHOR]

Since the insertion of urban infrastructure into the risk-taking world of financialisation, techniques for capturing added value from underlying revenue streams, from securitisation and derivatives to the structuring of bond and equity returns, have come to the fore. A value model, based on extraction through interest and dividends paid, as well as multiple fees, in our view, has benefited investors and financial intermediaries alike. Through the example of Carlsbad desalination plant in San Diego, California, the paper sets out to show how a piece of drinking water infrastructure was translated as a value asset to match the needs of institutional investors in the USA and beyond. The geography of value capture and its distribution globally is shown to be not simply financially innovative, but also spatially innovative and perhaps best understood through its topological spaces. [ABSTRACT FROM AUTHOR]

A new single-effect plate-fin desalination unit which utilizes solar or waste energy has been developed. This patented process is applicable for seawater desalination using simple and modular technology. In order to demonstrate the performances of this new process, a laboratory unit was constructed. It is composed of five evaporation cell, condensation cell, and heating cell and cooling cell. In this unit, a relatively large fraction of latent and sensible heat of condensation along with brine is successfully recycled and utilized. Since the falling film evaporation and fins are use, the average distilled water production is 0.5 m3/d. and the yield is about two times greater than that of a conventional single basin solar still with the same thermal energy input. The mean heat exchange coefficient between heating cell and evaporating film was around 2500 Wm-2K-1. The first result concerning the influence of the heating fluid temperature and the heating fluid flow rate are presented. Other factors which influence the freshwater yield are also discussed. [ABSTRACT FROM AUTHOR]

The knowledge of the characteristics of seawater is important for designers and engineers to design and construct a desalination plant with low operational problems. Therefore, establishing a database for Kuwait’s seawater characteristics is considered a crucial tool for researchers seeking to develop and improve desalination technologies for future applications. Because of this fact, this project was proposed to analyze the physical, chemical, and biological characteristics of Kuwait’s seawater at Subiya, Doha, Shuwaikh, Shuaiba, and Az-Zour, and other two locations that belong to the Kuwait Institute for Scientific Research (KISR) as Doha Research Plants (DRP) used as the intake for desalination/distillation research activities. A database on Kuwait’s seawater characteristics at the proposed locations was established. Then, the suitability of the proposed locations for future desalination activities was investigated depending on four fouling indices. The results obtained from the investigation of fouling indices were compared to the result obtained from experimental testing. This paper will summarize the results of the analysis and the experimental work and explore the best location for desalination activity in Kuwait and KISR. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • 3D cathodes provide an enhancement in the electrochemical softening method. • A comparison between a 2D and a 3D cathode is reported for water hardness removal. • Long-term electroprecipitation experiments assess the 3D cathode behaviour with time. • Water hardness is removed by precipitation of calcite, aragonite, and brucite. Abstract The electrochemical softening method to remove hardness from water has not been applied in desalination practice due to a high cathodic area requirement. In this work, the use of a 3D stainless steel wool cathode is proposed to overcome this technical limitation. An extensive comparison between the 3D cathode and a 2D Ti mesh has been presented, showing higher hardness removal for the 3D one. Experiments have been conducted with waters similar to concentrates derived from a brackish water treatment by electrodialysis. In addition, the method has been proved to be efficient for different water compositions in terms of hardness, alkalinity or the presence of an anti-scalant. The main influencing parameters (flow rate and current density) have been studied and it can be concluded that lower flow rates (below 1.2 L h−1) give rise to a better efficiencies and 100 A m−2 is the optimum current density. Moreover, the precipitate was characterised by SEM, EDX and XRD showing that Ca2+ is removed as calcite and aragonite (CaCO 3), whereas Mg2+ is precipitated as brucite (Mg(OH) 2). Finally, long-term experiments revealed that the 3D stainless steel cathode has a better performance than the 2D Ti mesh, but only at short times. [ABSTRACT FROM AUTHOR]

Water contamination and pollution pose health hazards to humanity and hence the need for their treatment. This study compared reverse osmosis (RO) and ultra-violet (UV) radiation in treating borehole water (BHW) and surface water (SW). The study area is Omoku community in Rivers State of Nigeria. The RO- and UV-treated waters were determined by their physicochemical characteristics and total Coliform, with the control to check the impact of each one. The obtained results showed slight variations, which were either significant or not. The pH of the treated BHW was slightly acidic with the value of 6.52. Water conductivity ranged from 40.33 μs/cm³ to 42.40 μs/cm³ for the BHW treated with RO, UV and control samples, respectively. SW conductivity attained a range of 425.07-800.0 μs/cm³. Turbidity of BHW were beyond the detectable limit but was higher than the WHO limit of <5.00NTU, while total suspended solid (TSS) of SW ranged from 9.08-46.43 ppm. Total dissolved solids (TDS) values of water were between 3.50 ppm and 16.67 ppm for RO treated BHW and higher than that of SW. There was a reduction of salinity of BHW from 40.7 mg/l to 11.8 and 21.6 mg/l following RO and UV treatment, while SW salinity was also reduced from 75.0 mg/l to 20 mg/l in RO treated water and 16 mg/l in UV treated water. In this study, RO and UV water treatment proved to be effective in producing potable water from both BHW and SW, although RO seemed to produce water with reduced mineral content in comparison to the UV treatment. Both methods effectively reduced heavy metals as well as Coliform. The physicochemical parameters tested were below the WHO recommended limits in most cases. It is recommended that both methods be incorporated in a single WT in order to gain the benefits of both technologies. [ABSTRACT FROM AUTHOR]

Abstract In a conventional HDH system, a constant feed of seawater is required to run the system. As a result of extracting freshwater from the saline water, it is rejected at higher salinity, thus it cannot be recirculated as a feed again. The aim of this study is to come up with a zero-brine discharge system that eliminates the continuous need for the supply of source and sink in the conventional system. Based on the fact that earth's atmosphere holds a vast amount of water that can be considered as a reliable freshwater resource, especially in coastal areas. A water-from-air system is proposed in this study. The proposed system configuration comprises of two parts, a basic HDH system that uses a liquid desiccant solution instead of saline water and a desiccant-based air dryer. The liquid desiccant leaves the HDH part at a higher concentration due to the extraction of freshwater. It then enters the air dryer where it is diluted by absorbing water vapor from the ambient air. This diluted desiccant is directed to the HDH part to close the desiccant loop. In this study, Lithium chloride is used as the working fluid of the proposed system. Mathematical modeling of heat and mass transfer processes between the air and desiccant in the humidifier and dehumidifier is developed to predict the performance of the desalination system. The proposed system produces about 8 kg of freshwater per hour. Highlights • The objective is to eliminate the supply of source and sink reservoir in an HDH system. • The proposed system consists of an HDH system that uses liquid desiccant solution and an air dryer. • The system consists of two loops, one for the desiccant solution and other for the HDH system. • A mathematical model for the air and desiccant in the humidifier and dehumidifier is developed. • The proposed system produces 8 kg of fresh water per hour. [ABSTRACT FROM AUTHOR]

Abstract Due in part to increased water demand and uncertainty around the availability of existing freshwater resources, there is interest in expanding the use of seawater desalination in the U.S. In order for greater adoption to occur, existing barriers need to be mitigated. One of these barriers is the energy consumption of seawater desalination. This paper reviews the existing energy requirements for membrane and thermal-based seawater desalination systems to produce potable water. Through literature review, it identifies the commercially-available option with the lowest energy intensity and the thermodynamic minimum energy requirement for each unit operation of the system. The paper then estimates the energy requirements to expand seawater desalination capacity to meet the potable water needs of water-stressed regions in the U.S. The results show that supplying 10% of the potable water demand for these regions located within 250 miles of a coastline using the lowest energy-intensity seawater desalination system commercially available would require <0.1% of 2018 U.S. electricity consumption. This increases to approximately 0.5% if all public water for these same regions is supplied via desalinated seawater. These estimates of the energy implications of broader adoption provide an initial comparison to current U.S. electricity consumption. Highlights • The energy intensity of seawater desalination systems is reviewed. • The energy for greater adoption of seawater desalination in the U.S. is projected. • A comparison is made to current overall U.S. electric consumption. [ABSTRACT FROM AUTHOR]

Abstract Microbial desalination cells (MDCs) are known among the bioelectrochemical systems for their green and cost-effective application in salt removal. However, the low efficiency of desalination compared to other chemical and membrane-based methods still holding this technology in laboratory and requiring further research and development (R&D) to establish actual plants. This study focused on integrating different applicable functions in one setup to promote applying MDCs in actual scale. In this research, the behavior of the MDC upon applying different salt concentrations in the desalination chamber was studied. Moreover, salt, sulphate and organic matter removal in acetate and sulphate-fed MDCs (A.MDC and S.MDC) were investigated. 10, 20 and 35 g/l of salt were successfully removed by using MDC technology. Sulphate removal of 72% was achieved within the S.MDC setup while similar current productions were observed in both A.MDC and S.MDC. Higher COD removal (88%) was recorded in S.MDC compared to 65% in A.MDC. Furthermore, the microbial communities were characterized and Rubrivivax was identified as the dominant genus in A.MDC while Desulfobulbus , Geobacter and Desulfovibrio were the most abundant genera in S.MDC setup. Highlights • Different concentrations of saline water were successfully removed in MDC. • Two types of acetate and sulphate-fed MDCs were enriched. • High salt and sulphate removal were simultaneously achieved in MDC. • Microbial morphology and community of two MDC types were discussed. [ABSTRACT FROM AUTHOR]

Normal growth of phytoplankton means gradual growth that allows mixed community to grow and allow a gradual succession of other phytoplankton species with a balanced and high biodiversity. In the contrary, a rapid, large-scale growth of certain species of phytoplankton is defined as harmful algal bloom (HAB). HABs cause water quality issues in fresh, brackish, and marine waters worldwide. In the Red Sea, HABs hinder normal operation of desalination plants and can even lead to their temporary shutdown. This research has already detailed how wastewater discharge from Red Sea desalination plants helps trigger HABs. The primary objective for this paper is to help manage and even mitigate this problem through development of a model to be used along with satellite images and physicochemical monitoring analysis as an early warning system for HABs near desalination plants in the Red Sea. To develop the model, physicochemical data were collected by sampling three coastal areas near desalination plants at Jeddah, Al Shoaibah, and Al Qunfudhah from December 2014 to November 2016. A total of 1,944 water samples were collected. To understand the unique environment of the seawater around the desalination plant that may trigger HABs, 15 parameters were measured. These parameters were divided into two groups, growth indicators (phytoplankton count, chlorophyll, phycoerythrin, dissolved oxygen, and turbidity) and those that might trigger the growth (temperature, conductivity, salinity, pH, total dissolved solid [TDS], nitrate, nitrite, ammonium, phosphorous, and silica). It was found that the highest concentrations of chlorophyll at Al Qunfudhah often exceeded the critical threshold level of 2 to 5 μg/L, which indicates the presence of an algal bloom. However, at Jeddah and Al Shoaibah chlorophyll concentration did not exceed this level. The results showed that higher temperature, salinity, TDS, and pH may promote some HAB species in environments that promote less phytoplankton diversity. Nitrate, phosphorus, and silica were the major nutrients that can trigger HABs. Prediction equations were developed using data from those parameters that promote HAB occurrence. [ABSTRACT FROM AUTHOR]

Abstract Desalination is becoming a competitive alternative for supplying quality water to irrigation districts in dry areas. However, its acceptance level among farmers is often low due to its higher price, the need for additional fertilization, and the misconception that it would negatively affect yield and crop quality. This work presents a decision support system that would help them to make irrigation management decisions regarding the optimal combination of saline and desalinated seawater (DSW), which would provide maximum economic profit. The model has been specially designed for Mediterranean greenhouse cropping systems. The proposed model was validated by applying it to a real watermelon crop which was experimentally monitored. A sensitivity analysis was then conducted in order to analyze the effect of different limiting factors on the optimal combination of water and the optimal profit for farmers. The application of the model to the case study demonstrated that it is profitable to use a blend of DSW and brackish water for irrigation of greenhouse crops. Despite the higher cost of the DSW, the economic optimum was achieved for higher DSW fractions than those which are used today. This sensitivity analysis has demonstrated that brackish water salinity, irrigation uniformity and crop tolerance are relevant factors that affect the optimal combination decisions. This work may encourage farmers to accept desalinated water. Graphical abstract Unlabelled Image Highlights • A decision support system to assist farmers in adopting the optimal blend of saline and desalinated water has been developed. • The model provides the maximum economic profit to the farmer while preserving the environment. • The model has been tested with the data obtained from a watermelon crop grown in a Mediterranean greenhouse. • The model recommends using more desalinated water than actually applied. • The optimal blend is sensitive to the brackish water salinity, crop tolerance to salinity and irrigation uniformity. [ABSTRACT FROM AUTHOR]

Electrodialysis desalination (ED) is an efficient process to desalinate brackish water and to minimize brine salinities to the level of seawater salinity. From the many models reported in the literature, some are simple but have a limited accuracy while others are complicated with a good accuracy. In this context, we explore the improvement of a fundamentally ‘lumped’ model by considering the voltage drop at the interfaces between membranes and solutions (which is the so-called Donnan potential) while conserving the model simplicity. The present model is developed by accounting for an electrical resistance of the Donnan potential in the total cell pair resistance. The results are presented in terms of total membrane area, flow path length, number of stacks and specific energy consumption. The results show that the improvement resulting from involving the Donnan potential was substantial for a high difference between the feed and product salinities as well as for low salinities (<500 ppm) of the product water and low flow velocities (<0.05 m/s). In general, the inclusion of Donnan potential improved the results from 4.4% up to 39.2% based on the studied cases. [ABSTRACT FROM AUTHOR]

The present work discusses the design and selection of a shell and tube condenser used in Low Temperature Thermal Desalination (LTTD). To optimize the key geometrical and process parameters of the condenser with multiple parameters and levels, a design of an experiment approach using Taguchi method was chosen. An orthogonal array (OA) of 25 designs was selected for this study. The condenser was designed, analysed using HTRI software and the heat transfer area with respective tube side pressure drop were computed using the same, as these two objective functions determine the capital and running cost of the condenser. There was a complex trade off between the heat transfer area and pressure drop in the analysis, however second law analysis was worked out for determining the optimal heat transfer area vs pressure drop for condensing the required heat load. [ABSTRACT FROM AUTHOR]

Water utilities often rely on industrial water supply (e.g. desalination) to complement natural resources. These climate-independent sources of supply allow operators to respond quickly to varying operating conditions, but require them to choose operating strategies, or rules. How does such operational flexibility impact the performance of water supply systems? How might it affect long-term plans for capacity expansion? Possibly significantly, as demonstrated by the analysis of a water supply system based on Singapore. First, we simulate the dynamics of the system under multiple rainfall and operating scenarios to understand the extent to which the operators’ behavior affect system performance. Results show that different operating rules can have comparable impact on the variability in system performance as hydrological conditions. Then, we show that small changes in the operating rules can lead to substantial changes in the capacity expansions, such as the size of a new desalination plant. [ABSTRACT FROM AUTHOR]

Among non-conventional water resources, desalination (from seawater or brackish aquifers) has emerged as a feasible option to deal with water shortage in arid and semi-arid areas. At the University of Alicante (UA, SE Spain), water availability is lacking and groundwater quality is poor. To ensure water availability, the UA built a small reverse osmose (RO) desalination plant (450 m 3 /day) to water the green areas and an urban park on the campus. The costs of a small private desalination plant, landscape irrigation, and the full cost of water, were assessed. This assessment considered the benefits made by new green areas existing in an urban space and citizens’ willingness to pay (WTP) for its preservation based on the contingent valuation method (CVM). The results indicated that the final desalinated brackish water cost was 0.29 €/m 3 and, according to the WTP results, the value that derived from the social benefits provided by the leisure area was 0.51 €/m 3 , being the final cost of water 0.22 €/m 3 . Consequently, the use of brackish water for irrigation has a high social value that should be considered when evaluating desalination-related projects. [ABSTRACT FROM AUTHOR]

The inhibition impact of aromatic nitro compounds on the corrosion of heat exchanger tubing material (titanium tubes) in MSF desalination plants in acid cleaning solution (1.0 M sulfuric acid) was explored. Corroborative results between chemical and electrochemical (EIS) methods have been reported. FTIR and SEM analysis were further used to characterize the morphology and the nature of the film adsorbed on the titanium surface. The study informed that the maximum corrosion rate of titanium (0.260 mg cm −2  h −1 ) was obtained in 1.0 M sulfuric acid at 298 K. Aromatic nitro compounds act as effective corrosion inhibitors for titanium in acid cleaning solution. The efficiency of these compounds boosts with concentration and diminishes with temperature. The aromatic nitro compounds exhibit a maximum inhibition efficiency of 73.0% (NI), 82.6% (NII) and 94.6% (NIII) at 600 ppm. They form a good protective layer on titanium surface through their adsorption. The adsorption of aromatic nitro compounds on titanium surface obeys Langmuir model. The performance of these compounds decreases in sequence: (NI) < (NII) < (NIII). [ABSTRACT FROM AUTHOR]

Improving the concentration ratio to reduce the emission of concentrated brine is required in some desalination plants. However, scaling problem will be aggravated with higher concentration. In this study, scaling tendency was analyzed according to two indexes including the Langelier Saturation Index and the Ryznar Stability Index. Four kinds of inhibitors were analyzed. Their inhibition performance under the condition of high concentration ratio in MED system was studied by both static jar tests and experiments on a small-scale falling film evaporation apparatus. Results indicate that severe scaling problems would occur when high concentration ratio encounters high temperature. Under the experimental condition, for which the temperature was 70 °C and the concentration ratio was 2.5, the alkaline scales were calcium carbonate. No magnesium hydroxide was formed. Calcium sulfate began to appear and increase when the concentration ratio exceeded 2. All inhibitors showed controlling effect on scale formation. Inhibitor A with its main constituents of HPAA and polymaleic acid showed the best inhibition performance. Better inhibition performance was achieved with higher inhibitor dosage, but no obvious improvement was observed when inhibitor dosage exceeded 5.5 ppm. The present study is helpful to the MED system under the condition of high concentration ratio. [ABSTRACT FROM AUTHOR]

The paper analyses the extrapolation of the results obtained in a pilot plant to a full-scale seawater desalination plant. A technological system was implemented in the pre-treatment line of Las Palmas III seawater reverse osmosis (RO) desalination plant with a capacity of 36,000 m 3 /d. This system is aimed to control membrane fouling. It consists in the non-dosing of sodium hypochlorite or another biocide to seawater in order to minimize RO membrane biofouling. The pH regulation at 6.5 controls the scaling and the 12.5 ppm dosage of FeCl 3 as a coagulant maximizes the coagulation efficiency of colloidal particles and controls the fouling process. [ABSTRACT FROM AUTHOR]

Ring opening reaction was used to prepare novel anionic surfactant as CaSO 4 .2H 2 O scale and mild steel (MS) corrosion inhibitor. The prepared surfactant was designed as Hexa-anionic surfactant, and named; Sodium(2Z,16Z)-8,11-bis((Z)-3-carboxylatoacryloyl)-5,14-bis(2-((4dodecylphenyl)sulfonamido)ethyl)-4,15-dioxo-5,8,11,14-tetraazaoctadeca-2,16-dienedioate. The Hexa-anionic surfactant was characterized by FTIR, and 1 HNMR. Platinum ring method was used to study surface active properties of the investigated surfactant. The anti-scale property of Hexa-anionic surfactant was evaluated according to a static test method. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX), and X-ray diffraction (XRD) were used to examine CaSO 4 ·2H 2 O crystal morphology. The high anti-scale performance of Hexa-anionic surfactant was related to its chelating, adsorption, and dispersion abilities. The scale inhibition ( SI %) reached the maximum 100% at concentration 7 ppm. Also, the inhibition performance of the insight surfactant for MS corrosion in synthetic water was tested by electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PDP) techniques, accompanied with surface analysis techniques. The obtained results indicated a good corrosion mitigation action of the investigated surfactant. SEM, and EDX show the formation of Hexa-anionic surfactant's adsorbed layer on the MS surface. The adsorption of Hexa-anionic surfactant at MS followed Langmuir adsorption isotherm. Quantum calculations confirmed the experimental data. [ABSTRACT FROM AUTHOR]

Air-conditioners are the highest energy consuming appliances in the offices of businesses, public and commercial buildings in hot humid climates. In Ghana, survey conducted indicates that 60–80% of electricity used in offices of public and commercial buildings is for air-conditioning. Many hot climates, and Ghana in particular, are endowed with high solar irradiations. The need for daytime office space cooling is actually as a result of high solar radiation levels. In the present work, studies have been conducted on the performance of a hybrid solar PV-grid powered air-conditioner for daytime office cooling in hot humid climates with a case study in Kumasi city, Ghana. A standard office of 30 m 2 floor area (105 m 3 office space) in a building with three of the sides sharing walls with adjacent offices, and the front side facing north was used for the study, with the air-conditioner set at a temperature of 20 °C. In the experiment, the pure sine wave hybrid inverter with integrated PWM charge control system was set to solar energy priority and supported by utility grid electricity when solar energy is not sufficient. It has been determined that for daytime office cooling, a 1040 Wp solar PV system with 200 Ah, 24 V battery configuration has a monthly mean solar fraction of 51% ± 9% for an air-conditioner with nominal cooling capacity of 2.5 kW and maximum power consumption of around 1.19 kW. The energy generation of the 1040 Wp solar PV system has been determined to be around 1211 kWh per year. Financial analysis has revealed that for the hybrid solar PV-grid powered air-conditioner, there is potential savings of US$ 1600 compared to 100% utility grid electricity in 10 years. It has also been estimated using available data that there is a potential of about US$ 3300 savings when the air-conditioner is powered with 100% solar energy compared to 100% utility grid electricity in 10 years, for daytime office use. [ABSTRACT FROM AUTHOR]