This study assessed six tomato (Solanum lycopersicum L.) cultivars within an integrated solar-powered closed hydroponic system in Al Dhaid, UAE (25°16′11.2″ N, 55°55′52.2″ E). The system combined an insect-proof net house, closed hydroponics, root-zone cooling, ultra-low-energy drip irrigation, and a cost-effective solar-powered reverse osmosis (RO) desalination unit to address salinity constraints. The cultivars, selected for their adaptability to controlled environments in the UAE, were evaluated for yield, water-use efficiency (WUE), and fertilizer-use efficiency (FUE). Among them, Torcida recorded the highest mean yield (0.619 kg/m2/harvest), WUE (27.1 kg/m3), FUE (26.5 kg fruit/kg fertilizer), and marketable fruit ratio (66.3%), followed by Roenza, Eviva, and SV 4129 TH; Lamina was intermediate, while Saley, a bushy type, produced the lowest yield. The top cultivars achieved cumulative yields exceeding 7 kg/m2—surpassing regional open-field benchmarks (4–5 kg/m2; 3–6 kg/m3). Compared with conventional cooled hydroponic greenhouses (3.5 kg/plant; 8 kg/m3), the system demonstrated similar productivity using three times less water. The RO unit produced water at baseline 1.05 USD/m3—58–68% below regional tariffs—while minimizing reliance on grid electricity and mechanical cooling. Overall, the integrated solar-powered hydroponic–RO model proved technically reliable, resource-efficient, and economically viable, offering a scalable solution for sustainable vegetable production in hyper-arid regions.

The treatment and management of landfill leachate is challenging due to its complex and variable composition. To comply with regulations, reverse osmosis (RO) is applied as an advanced treatment for highly polluting leachate, considering its satisfying removal efficiencies. Still, operational drawbacks such as membrane fouling and concentrate management limit the full promotion of RO technology for leachate purification. This study presents the technical performance of a full-scale RO facility located at the Hamici landfill in Algeria. Leachate characteristics were assessed over 24months from 2022 to 2023. Our work also evaluates the feasibility and limitations of RO technology, especially under high loads of organic compounds. The leachate had a high organic matter concentration, with chemical oxygen demand (COD) values ranging from 9940 to 21,500mg L-1, 5-day biochemical oxygen demand (BOD5) from 1175 to 3666mg L-1, and ammonia nitrogen (NH4+) levels reaching up to 3494mg L-1. Despite the fluctuations of the leachate's quality, the RO treatment maintained consistently satisfactory abatement, about 98% for COD, 90% for BOD5, and 94% for NH4+. However, membrane fouling was recurrent due to the high pollutant load of the leachate, resulting in repetitive downtimes and membrane replacement. Extensive and costly consumption of sulfuric acid (H2SO4, 98%), up to 12,800kg per month for pH adjustment before the RO unit, chemicals for membrane cleaning, and high energy demand were identified as the primary operational challenges in the present case study. Additionally, the hydrogen sulfide (H2S) emissions on-site and the RO's concentrate management need to be addressed to improve the sustainability of RO technology in the leachate treatment chain.

The use of lithium intercalation electrodes (LIE) for recovering lithium from geothermal sources (containing ≤ 400 ppm of lithium) has the potential to revolutionize the lithium mining industry. This work proposes a conceptual scaled-up process for LIE, utilizing concentrated brine of 15 m3 h−1 (384.32 mM or 2,666 ppm of lithium) obtained from a reverse osmosis unit. Given the high lithium concentration in the concentrated brine, testing LIE performance under high lithium content conditions (1 M LiCl) is essential. In this study, LiMn2O4 supported on vitreous carbon foam is evaluated as the positive electrode. Degradation of the intercalation-active material, LiMn2O4, was observed in acidic media, with significant manganese dissolution. In contrast, at near neutral pH, dissolution rate is considered lower. Faradaic efficiency in acid media showed 98% efficiency only during the first potentiostatic deintercalation run. Subsequent runs exhibited non-faradaic behavior, which was also attributed to manganese dissolution. To develop strategies for mitigating LiMn2O4 degradation, equilibrium diagrams for the Li-Mn-H2O system (Poubaix Diagram) was constructed. In addition to propose a scaled-up process for lithium recovery from geothermal sources, this work investigates the performance of lithium intercalation under conditions relevant to large-scale operations.

General Background: Access to safe drinking water remains a critical challenge in Indonesia, with nearly 30% of the population lacking proper access. Specific Background: Reverse Osmosis (RO) technology provides a solution for producing clean water, but conventional systems still face issues of efficiency, reliability, and safety. Knowledge Gap: Limited studies document the integration of automated control systems with RO units in real-world industrial applications. Aim: This study aims to develop and test a drinking water treatment control system using Schneider Smart Relay integrated with pH and TDS sensors. Results: Experiments on four water samples showed average pH of 7.67 (input), 7.80 (reject), and 7.86 (output), while average TDS values were 136 ppm (input), 298 ppm (reject), and 33.5 ppm (output). The system automatically activated or deactivated pumps according to preset water quality parameters, with buzzer alerts for anomalies, ensuring compliance with health standards. Novelty: The system combines automation, energy efficiency, and safety through smart relay integration, offering advantages over conventional RO setups. Implications: Findings demonstrate that this system can improve water treatment reliability and is suitable for household and industrial-scale implementation. Highlight: Automated RO system improved efficiency and water quality control Smart relay integration ensured safety and energy savings Applicable for household and industrial water treatment needs Keywords: Reverse Osmosis, Smart Relay, Drinking Water, pH Sensor, TDS Sensor

Abstract With growing water scarcity worldwide, water recycling is now a vital component to save water and ensure sustainable water management. Boilers are extensively used in various industries to generate steam for industrial processes and heating. Boiler operation results in polluted wastewater, which has to be specially treated before it can be released into the environment. Effective treatment of boiler wastewater is indispensable to ensure environmental protection as well as regulatory compliance. In this study, a specially designed pre-treatment facility was used for treating boiler wastewater from a hydrochloric acid factory. The wastewater was mixed with reverse osmosis (RO) unit effluents that supplied the production line, followed by reusing the treated water in Hydraulic acid liquefaction process. As an inexpensive pretreatment technique, effective removal of inorganic contaminants, 20%—30% diminution in the level of sulfate, and the levels of phosphate also diminished, whereas metals (zinc and iron) were reduced to the extent of approximately 70%–80%. The Water Quality Index (WQI) indicates fair quality and demonstrates that the system was effective in improving water quality. Life Cycle Assessment (LCA) further revealed that integrating economic and environmental strategies is essential for sustainability. Consequently, 80% of the plant’s wastewater was successfully recovered and reused in a neighboring sulfuric acid production line, achieving a Minimal Liquid Discharge (MLD) outcome.

With water availability being one of the world’s major challenges, this study aims to propose a Zero Liquid Discharge (ZLD) system for treating saline effluents from an urban wastewater treatment plant (UWWTP), thereby supplementing into the existing water cycle. The system, which employs membrane (nanofiltration and reverse osmosis) and thermal technologies (multi-effect distillation evaporator and vacuum crystallizer), has been installed and operated in Cyprus at Larnaca’s WWTP, for the desalination of the tertiary treated water, producing high-quality reclaimed water. The nanofiltration (NF) unit at the plant operated with an inflow concentration ranging from 2500 to 3000 ppm. The performance of the installed NF90-4040 membranes was evaluated based on permeability and flux. Among two NF operation series, the second—operating at 75–85% recovery and 2500 mg/L TDS—showed improved membrane performance, with stable permeability (7.32 × 10−10 to 7.77 × 10−10 m·s−1·Pa−1) and flux (6.34 × 10−4 to 6.67 × 10−4 m/s). The optimal NF operating rate was 75% recovery, which achieved high divalent ion rejection (more than 99.5%). The reverse osmosis (RO) unit operated in a two-pass configuration, achieving water recoveries of 90–94% in the first pass and 76–84% in the second. This setup resulted in high rejection rates of approximately 99.99% for all major ions (Cl−, Na+, Ca2+, and Mg2+), reducing the permeate total dissolved solids (TDS) to below 35 mg/L. The installed multi-effect distillation (MED) unit operated under vacuum and under various inflow and steady-state conditions, achieving over 60% water recovery and producing high-quality distillate water (TDS < 12 mg/L). The vacuum crystallizer (VC) further concentrated the MED concentrate stream (MEDC) and the NF concentrate stream (NFC) flows, resulting in distilled water and recovered salts. The MEDC process produced salts with a purity of up to 81% NaCl., while the NFC stream produced mixed salts containing approximately 46% calcium salts (mainly as sulfates and chlorides), 13% magnesium salts (mainly as sulfates and chlorides), and 38% sodium salts. Overall, the ZLD system consumed 12 kWh/m3, with thermal units accounting for around 86% of this usage. The RO unit proved to be the most energy-efficient component, contributing 71% of the total water recovery.

This investigation attempts to develop a tower solar collector-based system designed for the cogeneration of cooling and desalination. The traditional organic Rankine cycle (ORC) integrated with the ejector refrigeration cycle generates limited power and cooling at a single temperature. Acknowledging their limitations, our present study uses an organic flash cycle (OFC) supported by solar heat combined with the two-phase ejector cycle and the reverse osmosis (RO) desalination unit. Since the OFC turbine is fed with two extra streams of fluid, therefore, it provides greater power to run the compressor of the ejector and pumps of the RO unit, resulting in the production of cooling at two different temperatures (refrigeration and air conditioning) and a higher mass flow rate of fresh water. A mathematical model is employed to assess the impact of coil curvature ratio, Rib height, and direct normal irradiation (DNI) on the temperature of the collector’s oil outlet. ANSYS-FLUENT conducts numerical simulations through computational fluid dynamics (CFD) analysis. The results indicate an ultimate increase in oil outlet temperature of 45% as the DNI increased from 450 to 1000 W/m2 at a curvature ratio of 0.095 when employing the 1st Rib. Further, a steady-state energy and exergy analysis is conducted to evaluate the performance of the proposed cogeneration, with different design parameters like DNI, coil curvature ratio, rib height, and OFC turbine inlet pressure. The energetic and exergetic efficiencies of the cogeneration system at DNI of 800 W/m2 are obtained as 16.67% and 6.08%, respectively. Exergetic assessment of the overall system shows that 29.57% is the exergy produced as cooling exergy, and the exergy accompanied by freshwater, 68.13%, is the exergy destroyed, and 2.3% is the exergy loss. The solar collector exhibits the maximum exergy destruction, followed by the ejector and RO pumps. Integrating multiple technologies into a system with solar input enhances efficiency, energy sustainability, and environmental benefits.

Elevated fluoride levels in drinking water pose a significant health risk for communities relying on groundwater in the Ethiopian Central Rift Valley. This study aims at characterizing real groundwater samples from the Ethiopian Central Rift Valley and evaluating the performance of an integrated membrane process based on reverse osmosis (RO) and membrane crystallization (MCr) for fluoride removal and its recovery as mixed fluoride salts. Groundwater analysis revealed fluoride concentrations of 20.8 mgL−1 at the Meki-01 site and 22.7 mgL−1 at the Meki-02 site, both exceeding the WHO guideline of 1.5 mgL−1. In addition, total dissolved solids exceeded 1000 mgL−1 at both sites, classifying the water as brackish. A commercial RO membrane demonstrated excellent fluoride and ion rejection, with fluoride removal rates exceeding 99%. The total dissolved solids (TDS) removal efficiency reached 89%. The mean water permeability of the membrane was 4.52 Lm−2h−1bar−1. The retentate produced in the RO unit reached a concentration of 70 mgL−1, which was then treated using osmotic membrane distillation–crystallization (OMD-Cr) and/or vacuum membrane crystallization (VM-Cr). This process facilitated the recovery of mixed salts while achieving an almost zero-liquid discharge. The study confirms the successful removal of fluoride and its recovery as mixed salt, along with the recovery of water in an environmentally friendly and manageable way.

Basrah is the richest town and the economic capital of Iraq. It suffers from lack of drinking water. This project is a dream to supply drinking water to Basrah citizens within WHO standards. Water should pass sedimentation and filtration stages before interring reverse osmosis unit. The design is carried out using lewaplus2 software. Several parameters should be selected in the design step membrane type, number of stages, number per element in each stage, and the recovery percentage. An optimization is carried out using Minitab ver. 18 for the acceptable limit of TDS and minimum cost and it was found that the optimum conditions were 52% for first stage, the numbers of vessels are 20 for both the first and second stage. In addition, results showed that the pressure and the total dissolved solid increase with increasing the recovery while parameters like the feed flow rate per vessel, the power, and the cost are decreasing with the recovery. Mathematical model described the cost was conducted and statistical study was also done to ensure the results.

Access to clean and potable water is a growing global concern, particularly in coastal and arid regions where freshwater sources are scarce. Traditional desalination tech- niques, such as thermal distillation and conventional reverse osmosis, rely heavily on fossil fuel-based energy sources, leading to high operational costs and significant environmental impacts, including greenhouse gas emissions. Additionally, these systems often require complex infrastructure, making them inaccessible to remote and off-grid communities. To address these challenges, this research presents a novel solar-powered desalination machine that integrates Reverse Osmosis (RO) and Ultraviolet (UV) purification technologies. The proposed system harnesses solar energy to power high-pressure pumps, eliminating dependency on non-renewable energy sources. The RO unit effectively removes dissolved salts and contaminants, while the UV purification stage ensures microbial disinfection, delivering high-quality drinking water. By utilizing renewable energy, the system significantly reduces operational costs and minimizes carbon emissions, mak- ing it an environmentally sustainable and economically viable solution. The impact of this research extends to enhancing water security in remote and disaster-prone areas, providing a decen- tralized, self-sustaining water purification solution. Experimental results demonstrate the system’s efficiency in reducing Total Dissolved Solids (TDS) to potable water standards, ensuring safe and reliable water supply. Future advancements will focus on optimizing energy utilization, improving membrane longevity, and integrating smart automation for real-time performance monitoring. This study contributes to the global effort of sustain- able desalination, paving the way for cleaner and more accessible water resources. Index Terms—Solar Energy, Seawater Desalination, Reverse Osmosis (RO), UV Purification, Water Scarcity, Renewable En- ergy Photovoltaic (PV) Systems, Membrane Technology.

The presence of dissolved sulfides in feed seawater causes severe elemental sulfur fouling in the reverse osmosis (RO) process. However, current pretreatment methods suffer from large footprint, high energy consumption, and limitations in effluent quality. In this study, adsorption and microfiltration are merged into a single process for the pretreatment of sulfide-containing seawater. Powdered activated carbon (PAC) was selected for its superior adsorption capacity (14.6-fold) and faster kinetics (3.9-fold) for sulfide removal compared to granular activated carbon. The high surface area and multiple pore structures of PAC facilitate surface and intraparticle diffusion, as well as anion-π conjugation likely occur between PAC and sulfide. Polypropylene microporous membranes, capable of tolerating high PAC dosages, were used in the hybrid process. Long-term pilot tests demonstrated that the effluent (turbidity < 1 NTU and SDI15 ≈ 2.50) met the quality requirements for RO unit feedwater, achieving 100% sulfide removal efficiency over 101 h, with no risk of PAC leakage throughout the entire operation process. The formation of a loose, porous PAC cake layer alleviates membrane fouling and enhances the retention and adsorption of metal(loid)s and sulfide. Moreover, the low permeate flux of the polymeric membranes significantly mitigates filter cake formation. The hybrid system adapts to variations in feedwater quality, making it highly suitable for desalination plants with limited space and budget. These findings offer valuable insights and practical guidance for advancing seawater desalination pretreatment.

In recent decades, water shortages have become a significant problem. Sudan is no exception. In addition to the main towns of Port Sudan and Suakin, many villages scattered along the Red Sea coast also experience severe shortages of fresh water and electricity supply. The problem recently worsened after the Arbaat Dam's collapse, which was Port Sudan's main source of fresh water. Desalination of seawater and brackish water can play a significant role in addressing this issue. In this field, reverse osmosis (RO) is predominant due to its many advantages. However, this technology consumes a significant amount of energy. In many places around the world, freshwater shortages are accompanied by an abundance of solar energy. In this study, one of the existing desalination plants in Port Sudan was considered to investigate the possibility of shifting it to run on solar power instead of electricity from the national grid, or that generated by diesel engines. The plant under study is a small RO unit with a capacity of 7 m3/h. It consumes energy at a rate of 6.6 kWh/m3. PVsyst software has been used to design and simulate the solar photovoltaic system which can drive the desalination unit. Results showed that with a PV array total power of 95.2 kW and 9360 Ah battery capacity, the system can work steadily for 7 hours daily to produce 49 m3/day of fresh water. The solar system's p annual performance ratio (PR) is 60.3% with a solar fraction equal to 100%. While the simple payback period (SPB) for the photovoltaic system is found to be 1.74 years.

The paper studies the operation of a highly mineralized water purification system with a reverse osmosis unit for the needs of a metalworking enterprise. It identifies the reasons for the unsatisfactory operation of the water purification system and develops recommendations for its improvement based on the assessment of water quality in samples at water treatment stages and the assessment of the tendency of the feed water to form silt on reverse osmosis membranes. The work aims to develop an effective technology for purifying highly mineralized water, which contains both ammonium and iron ions, based on the study of the existing water purification system at the enterprise. Groundwater is chloride-sulphate calcium-magnesium and does not meet the requirements for drinking water in terms of turbidity, total mineralization, total hardness, ammonium, total iron, silicates, magnesium, manganese, sodium, strontium, and chlorides. Standard methods were used to determine water quality indicators at various water treatment stages. Highresolution scanning electron microscopy was used to analyze the surface of the filter material grain. The elemental composition of the filter material grain and its surface sediment were analyzed locally using energy dispersive spectrometry. The hypothetical composition of groundwater and the quality of water at various water treatment stages were investigated; the silt density index, the Langelier index, and the Gibbs energy of carbon dioxide equilibrium in the aerator were calculated; the aeration system performance was assessed. The reasons for the performance slowdown of the reverse osmosis unit and the frequent replacement of the pressure filter media were identified. The tested water supplied to the reverse osmosis unit does not meet the requirements for total hardness and total iron. The insufficiency of the specific air flow rate in the aerator was proven. Mudding of granular filter material with calcium carbonate and amorphous silicon was observed. Technical solutions are proposed to increase the efficiency of aeration-degassing and iron removal at the preliminary water purification stage before reverse osmosis. The proposed solutions will be relevant for the design and operation of process flows for complex groundwater purification.

The demineralization of brackish water through reverse osmosis (RO) represents a strategic and sustainable solution to meet the increasing water demands in the southeastern regions of Morocco, particularly in arid areas such as Zagora. Despite its effectiveness, the RO process remains highly energy-intensive, primarily due to the operation of high-pressure pumps, which account for 40% to 55% of total operating costs. Furthermore, a substantial amount of hydraulic energy is lost when the concentrated brine is discharged at atmospheric pressure, highlighting a major inefficiency. To address this challenge, the present study investigates the integration of an isobaric Pressure Exchanger (PX) as an energy recovery device to enhance the energy performance of a reverse osmosis unit. Using real operational data collected from the Zagora demineralization plant specifically pressure and flow rate readings from the OS1 and OS2 reject lines a detailed numerical simulation was conducted to quantify the recoverable hydraulic energy and analyze its variation over time. The results emphasize the critical role of energy recovery technologies in improving the sustainability, efficiency, and environmental footprint of desalination plants in Morocco. Integrating such systems aligns with the country’s strategic goals for resource optimization and the energy transition in water infrastructure.

The demand for good quality drinking water is experiencing strong growth on a global scale, particularly in emerging countries, such as the BASIC countries (Brazil, South Africa, India, and China). For this reason, sea or brackish water desalination technology using membrane filtration technique is a very effective and sustainable method for dealing with this problem. In this work, the performance study of the reverse osmosis desalination plant of Nouadhibou-Mauritania coupled or not to an energy recovery unit was carried out using the Matlab/Simulink software. The objective of this work is to study the functional and productive performance of the reverse osmosis unit by examining the importance of the pressure exchanger in such systems, by acting on the mixing rate of feed water with the flow of water delivered by the pressure exchanger. This study shows that the exploited Energy Recovery devices (ERDs) have a very favorable economic and energetic profitability of 75% reduction, which reduces the specific power consumption by 5 instead of 14.5 kWh/m3 in the case of a system without and with the ERDs, for productivity of 800 m3/d and a recovery rate of 20%.

Hydrogeological studies of the Sepidan basin to supply required water from exploiting water wells of the Chadormalu mine utilizing reverse osmosis (RO) method

Techno-economic optimization of a trigeneration system attaining water-heat-energy nexus considering an underground gravity energy storage

Abstract This article presents a comprehensive study of a double-acting cylinder (DAC) energy recovery device (ERD). The DAC was specifically designed, manufactured, and experimentally tested within a small-scale 5 m3/day brackish water reverse osmosis (RO) unit. The distinctive advantage of the DAC lies in its ability to operate without an extra booster pump, thereby reducing initial costs and streamlining system complexity. A comparative analysis was conducted between the station operating without any ERD and the station equipped with a DAC. For both scenarios, a parametric study was carried out to analyze the relationship between specific energy consumption (SEC) and recovery ratio at varying recovery percentages (10%, 15%, 20%, 25%, and 30%) for different salinity levels. This analysis was conducted across various feed flowrates, with the percentage reduction in SEC calculated for each case. The results show the DAC's ability to effectively reduce the SEC by up to 40%. Additionally, the study investigated brine-feed stream mixing within the DAC, highlighting its capability to prevent undesirable mixing despite internal leakage. However, its widespread adoption has been hindered by realizable pressure fluctuations associated with its implementation, which can lead to rapid fatigue failure. To address this issue, a direct-contact air vessel was integrated into the system to minimize pressure fluctuations and enhance the performance of the DAC. Its optimal size was determined through numerical analysis using the method of characteristics, with detailed design equations presented for future reference. The results affirm the indispensable function of the air vessel in attenuating unsteady effects.

Abstract Water shortage is one of the main problems for small, isolated islands, especially in the Mediterranean Sea. Water supply in those areas relies on maritime transport through tanker ships, especially during periods of high demand. However, this solution is unsuitable for isolated islands due to the high costs and environmental impact. This study aims to assess the feasibility of powering a desalination facility in a remote location with renewable energy sources to assess the potential cost savings and reduction of greenhouse gas emissions compared to the current supply mechanisms. To this end, the Greek island of Tilos is selected as a case study due to its high unexploited renewable energy production during winter months. The study hypothesizes using a seawater reverse osmosis (SWRO) unit to increase the sustainability of the water supply and promote the island’s self-sufficiency. Two control strategies have been adopted, simulating a demand-driven and a renewable production-driven scenarios. Results show a levelized cost of water that ranges between 1 and 2 €/m3, which is consistent with the average cost for the existing desalination plants in Grece. The adoption of a SWRO facility coupled with water storage systems results always in a more cost-effective solution than maritime transport, leading also to a relevant reduction of the environmental impact.

One of the global issues of our time is the shortage of freshwater resources. Desalination of marine and brackish waters is a promising solution to this problem. The most common desalination technologies are thermal (distillation) and baromembrane (reverse osmosis and nanofiltration) processes. When designing demineralization stations with reverse osmosis units, it is necessary to consider a number of limitations associated with higher requirements for pretreatment of water entering the unit. The use of thermal desalination plants makes it possible to obtain fresh water of higher quality, and less stringent requirements are imposed on the preliminary preparation of water for this type of unit. However, during the operation of desalination plants of this type, scale forms on the heating surfaces, which negatively affects the efficiency of the unit. Scale is formed less intensively in the units with contact vapors, since in this case the evaporation process occurs in volume. Thus, the development of thermal scheme of such unit and the study of their operation is relevant. The tasks have been solved using the methods of experimental studies of heat and mass transfer processes, mathematical processing of experimental data, and balance calculations of power plants. A thermal scheme of a thermal desalination plant with a contact evaporator with compression of a vapor-air mixture has been developed. Thermal and material balance has been compiled, on the basis of which energy costs have been determined to obtain m3 of fresh water. The authors have proved the determining influence of the temperature of desalinated water in the bubbling zone on the productivity of desalination plants with a contact evaporator. An amendment has been obtained that allows the initial salinity of water and brine to be considered when calculating the operating cycle of the unit. As a result of the analysis of the results obtained, it is found that an increase in the water temperature in the bubbling zone allows us to increase the productivity of the unit, and an increase of the drying temperature of the vapor-air mixture leads to a decrease of the energy consumption of the desalination plant. The introduction of an amendment considering the salinity of the source water and brine makes it possible to increase the accuracy of calculating air humidification up to 15 %.