Reverse Osmosis Unit Research Articles

Исследование работы термической опреснительной установки с контактным испарителем и компрессией паровоздушной смеси

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 %.

Techno-economic process design of multi-stage flash- reverse osmosis for water and power production using solar-wind resources

This paper introduces a newly developed hybrid power plant design that combines renewable energy sources to produce both electricity and freshwater. The design offers a higher gain output ratio (GOR) and improved efficiency in power and freshwater production, all at a lower cost compared to existing research papers. To generate power, the power plant incorporates a range of technologies, such as a horizontal-axis wind turbine (WT), photovoltaic panels (PV), parabolic trough collectors (PTC), a steam Rankine cycle, a multi-stage flash (MSF) desalination unit that cleverly harnesses excess heat from the Steam Rankine cycle, and an Reverse osmosis (RO) unit. With the assistance of ASPEN Plus, ASPEN Economic, and HOMER PRO software, the process parameters undergo significant improvement. According to the results, the power plant has the capacity to generate 57.63 MW of electricity and produce 2505 m3h of freshwater. Additionally, it has a GOR of 9.09 and utilizes 7285 m3h of seawater, which has a renewability factor of 97.6 %. In addition, the efficiency of the steam Rankine cycle stands at 32 %, providing notable energy savings. The production costs for electricity and freshwater are 0.037 $kW and 1.38 $m3, respectively, indicating their affordability. The economic analysis reveals promising results for the project, with an anticipated annual profit of 41 % and a relatively short capital payback period of 2.4 years. By implementing the proposed hybrid cogeneration power plant, the region can tackle its water and energy scarcity issues with a sustainable and long-lasting solution.

Integrating renewable energy technologies in green ships for mobile hydrogen, electricity, and freshwater generation

This research investigates a sustainable and renewable mobile energy system designed for electricity production, hydrogen generation, and seawater desalination. It targets critical energy and freshwater needs during disaster scenarios, particularly in island nations and coastal cities where infrastructure may be compromised. The system integrates advanced technologies, including wind turbines, photovoltaic panels, solar collectors, and reverse osmosis units, all mounted on a green ship. Simulations using Engineering Equation Solver software indicate that in July, the system can produce 2,201,865 MJ of electricity, 7252 kg of hydrogen, and 3456 tons of fresh and hot water. This output can power 1072 electric vehicles and 1284 hydrogen-powered vehicles while supplying cold water to 57,600 people and hot water to 5760 people. By relying on renewable energy, the system prevents approximately 43,543 kg of carbon emissions in July. The total monthly economic value is estimated at $47,241.36, demonstrating its potential as a sustainable solution for disaster response and coastal communities.

Techno-economic investigation of an entirely solar-powered hybrid HDH/RO desalination plant for moderate water demand under various operating conditions

The study presented a scalable, entirely solar-powered hybrid desalination system suitable for moderate demand and valid for various water salinities. The system merged two desalination techniques: HDH (humidification-dehumidification) and RO (reverse osmosis) units. The required power for all components was obtained from a photovoltaic system. The experiments were conducted to evaluate the separate units and hybrid system performances under different conditions, including various sprayed hot water (to the HDH) temperatures, RO feed water temperatures, air velocities, and water salinities. Based on the recorded data, the techno-economic analyses were conducted to assess the gain output ratio (GOR), recovery ratio (RR), specific energy consumption (SEC), the total amount of dissolved solids (TDS), and product cost. As a result, the RO unit's productivity increased almost linearly with feed temperature, showing a maximum hourly yield of 60 L/m2. In contrast, HDH productivity showed exponential growth with feed temperature, achieving a maximum hourly yield of 18 L/m2. The SEC of the RO unit decreased from 1.1 kWh/m³ to 0.63 kWh/m³ when using the rejected HDH's hot brine. The hybrid system's accumulated productivity reached 535 L/m2, significantly higher than the standalone HDH (58.5 L/m2) and standalone RO (368 L/m2). Additionally, the hybrid system demonstrated substantial improvements in GOR and RR, with daily values of 11.15 and 55.73%, respectively. Economically, the distillate water cost was significantly lower, at 0.63 $/m³ for the HDH/RO system compared to 3.51 $/m³ for the standalone HDH.

Integrated wind farm solutions: Harnessing clean energy for electricity, hydrogen, and freshwater production

This research explores the design, modeling, and feasibility of a multi-energy wind power plant in South Korea, aimed at producing electricity, fresh water, hydrogen, and oxygen. The main goal of the current study is to help the energy production system that uses the high potential of wind energy in areas with wind potential to increase power and efficiency and reduce harmful environmental effects for the production of hydrogen and fresh water. The system employs a PEM electrolyzer unit and reverses osmosis technology for hydrogen, oxygen, and freshwater generation. The innovation of this study lies in the integration of wind farm design with optimal electricity allocation to electrolyzers, reverse osmosis units, and the grid, maximizing efficiency and sustainability. A comprehensive case study is presented, evaluating the viability of putting the suggested strategy into practice in ten South Korean cities, with a focus on hydrogen production from wind energy. The study investigates ten scenarios for selecting the number of wind turbines, electrolyzers, and reverse osmosis devices, and sixteen scenarios for dividing wind farm coefficients to supply grid electricity, electrolyzer electricity, and reverse osmosis electricity. The optimal result indicates that 5% of wind farm electricity should be allocated to reverse osmosis units, 15% to electrolyzers, and 80% to the grid. The economic analysis indicates that among the system components, the wind farm, reverse osmosis, and PEM electrolyzer represent the highest costs. The system's performance is assessed across ten cities in South Korea, with Yeosu, Incheon, and Busan determined to be the best sites for the proposed power plant because of their strong potential to produce hydrogen using wind energy. Implementing the system in Yeosu, the optimal city, may stop 9664.326 tons of carbon dioxide from being released, generate 47374.15 MWh of electricity, and expand 46 ha of green space. Additionally, selling 9474.83 MW of electricity to the grid would meet the annual electricity needs of 929 people in Yeosu, South Korea. This study emphasizes the potential of wind power plants in South Korea to contribute to sustainable energy production and carbon dioxide reduction, highlighting their potential for a greener and more sustainable future.

Multi-objective optimization of a solar-biomass multi-generation system with dual-stage desalination for brine minimization

A hybrid solar-biomass multi-generation system feeding an off-grid community is proposed in this study. An organic Rankine Cycle (ORC) generates electricity by harnessing the thermal energy supplied by the hybrid heat generation system. Part of the produced electricity is utilized to meet the community's electricity needs, while another fraction powers a brackish water reverse osmosis unit (RO). The waste heat from the ORC is recovered to produce domestic hot water and to drive a membrane distillation (MD) unit for RO brine minimization. A multi-objective optimization of the proposed system is conducted using the NSGA-II algorithm and TOPSIS decision-making tool considering plant's overall energy efficiency, exergy efficiency, and the total exergoeconomic cost of the useful products as objective functions. The study's results indicate that the overall optimal solution is achieved using R1336mzz(Z), with corresponding energy efficiency, exergy efficiency and hourly exergoeconomic cost of 45.31%, 5.39%, and 87.68 €/h, respectively. Moreover, the unitary costs associated with the useful products are 0.207 €/kWh, 0.029 €/kWh, 0.683 €/m3, and 3.36 €/m3 for the produced electricity, domestic hot water, RO permeate and MD distillate, respectively. In terms of sustainability, the system is not only renewable-driven but also achieves a 21% reduction in brine discharge through heat recovery at the ORC condenser compared to single-stage RO desalination. Additionally, using R1336mzz(Z) with its low global warming potential of 2 significantly lowers CO2 equivalent emissions compared to R245-fa. Lastly, sensitivity analysis indicates that hybridization ratios of up to 80% can result in a 10.6% reduction in CO2 emissions originating from biomass combustion compared to biomass-only solutions.

Application Research of an Automatic Control Seawater Reverse Osmosis (SWRO) System Based on the Siemens PLC

To solve the global environmental problem of a shortage of freshwater resources, seawater desalination is considered one of the most promising solutions. In this research, the main novelty of the seawater desalination system lies in its utilization of a reverse osmosis unit as the core process for producing drinking water. By optimizing the pretreatment section in the process flow, a seawater reverse osmosis (SWRO) control system based on Siemens PLC with a high degree of automation was developed, which has the advantages of convenient maintenance and monitoring. In addition, through research on reverse osmosis systems, the results showed that within two years of operation, the total desalination rates of the primary and secondary reverse osmosis systems were not less than 99% and 97.5%, respectively. Furthermore, the water quality after desalination was tested. When the doses of CaCl2, MgCl2 and NaHCO3 were 20 mg/L, 15 mg/L, and 50 mg/L, respectively, high-quality drinking water was obtained. Finally, a reasonable process plan and corresponding estimates were given for the complex water source conditions. Compared with traditional seawater desalination systems, our system has the advantages of easy operation, efficient water production and lower price. Accordingly, this study will help to solve drinking-water problems in some freshwater-scarce regions.

Zero liquid discharge management: optimizing sustainable reverse osmosis desalination practices

This study introduces a Zero Liquid Discharge (ZLD) scheme for Reverse Osmosis (RO) desalination, integrating ultra-filtration pretreatment and Electrodialysis (ED) for brine concentration. The scheme divides brine reject into fractions, directing them to an electrolyser and evaporator powered by renewable energy sources. Notable findings include the treatment plant's capability to produce 792 cubic meters of fresh water daily, while decreasing salt concentration from 4,660 ppm to 30 ppm, showcasing efficient desalination. Additionally, recycling fractions of RO unit waste to various components enhances resource efficiency. The study highlights the daily production of 2,269.27 kg of hydrogen, coupled with minimal electricity consumption of 74,885.91 kWh, thereby improving overall energy efficiency. Furthermore, the utilization of solar energy significantly reduces reliance on fossil fuels, thereby promoting sustainability and mitigating the environmental impacts associated with traditional energy sources. Solar energy is a clean, renewable resource that helps decrease greenhouse gas emissions and other pollutants, contributing to cleaner air and a healthier planet. This shift towards renewable energy is crucial in addressing climate change and ensuring a sustainable future for generations to come. In the context of desalination, emphasizing environmental preservation and water security is paramount. Desalination processes, while providing essential fresh water in arid regions, often produce brine as a byproduct. The brine, with a high salt concentration of 13,648 ppm, poses a disposal challenge that can negatively impact marine ecosystems if not managed properly. This is where Zero Liquid Discharge (ZLD) systems come into play. With a ZLD index of 2.7%, these systems ensure that all wastewater is treated and reused, leaving no liquid waste behind. ZLD technology captures and recycles every drop of water, converting waste into reusable resources, thus minimizing environmental harm. The model showcased a significant decrease in brackish water extraction from 1,200 cubic meters per day to 871.52 cubic meters per day, marking a notable 27% reduction. These results highlight the promising effectiveness of the proposed ZLD scheme in enhancing the efficiency of brackish water treatment, demonstrating its potential to significantly reduce the demand for fresh water resources while achieving sustainable desalination practices. This article will present a detailed yet a simple description of reverse osmosis and ZLD, how do they correlate and how these two technologies represent the future of water treatment.

A new approach to wind farm stabilization and peak electricity support using fuel cells: Case study in Swedish cities

The present article introduces and investigates a new approach for shaving the peak electricity demand and mitigating energy instability. At the heart of this concept is a smart integration for efficient hydrogen production/storage/usage to minimize energy costs and maximize the renewable penetration in the local electricity grid. The system is driven by a wind farm integrated with proton exchange membrane (PEM) electrolyzers and reverse osmosis desalination units for efficient electricity, hydrogen, and freshwater production. It also combines with PEM fuel cells equipped with a hydrogen tank to meet the demand constantly when renewable electricity is unavailable or unstable. The system's practicality is assessed and compared for various Swedish cities with high wind potential from thermodynamic, economic, and environmental aspects to see where it works effectively. The comparative results of various scenarios show that integrating 32 wind turbines, 2 electrolyzers, and 2 reverse osmosis units, with 25% of electricity going to electrolyzers, 20% to reverse osmosis, and 55% to the grid, is the most optimal configuration/allocation. Optimal locations for the power plant are identified in Visby, Halmstad, and Lund due to favorable wind conditions. Setting up the system in Visby could prevent 1878.2 tonnes of CO2 emissions, generate 93,910 MWh of electricity annually, and create 213 ha of green space. The proposed system in Visby could boast the biggest electricity generation capacity, reaching 11,263 MWh, sufficient to power 938 households. Scaling this model to 12 cities in Sweden could provide the electricity needs of 4500 households, demonstrating the potential for widespread impact.

Outbreak of Ralstonia spp. and Burkholderia spp. Catheter-Related Bloodstream Infection in Hemodialysis Unit

The Ralstonia species (RB) and Burkholderia species (BB) are bacteria responsible for nosocomial infections in frail patients such as hemodialyzed (HD) patients. Here, we report how we managed an outbreak caused by RB and BB that occurred in a dialysis unit. From the 7th to the 16th of April 2021, an infection due to RB and BB occurred in 7 out of 39 (17.9%) HD patients with central venous catheter (CVC). Disinfectants, CVC-lock therapy solutions, water by reverse osmosis unit (ROW) and dialysis concentrates were cultured, including the biofilm from the loading plastic tubes (LPTs) that connect the hemodialysis consoles (HCs) to the ROW delivery line. The antibiotic treatment was successful for all patients. RB and BB were isolated in the biofilm of 11/37 LPTs. Three out of 11 positive LPTs were associated with the infected patients. The ROW delivery line was modified to provide a whole disinfection with the HCs connected, avoiding the risk of new contamination of the LPTs. A filtration module of 0.01 mm was added prior to the ROW delivery line. Our experience suggests that outbreaks sustained by unusual bacteria such as RB and BB should be promptly investigated to treat the infected patients with the appropriate therapy and to identify the possible source of infection, making the needful changes to achieve a safer dialysis unit.

Research on Intelligent Water Treatment Strategy based on DCS Control System

Abstract In a capacity renovation project, the new DCS system as the equipment control system, and the existing AB 1756 series PLC system, there are two control systems bi-directional signal monitoring problems. This paper compares two methods of monitoring bi-directional data transmission, and analyzes and verifies the advantages and disadvantages of the two methods. From the perspective of reliability and safety of implementation, a protocol special communication card was added in the PLC controller card slot of desalination plant, and added a protocol-specific communication card to the PLC system card slot of the secondary reverse osmosis and EDI units. The actual project verification shows that this method can ensure reliability and safety performance while realizing functions.

Enhanced impregnation of iron‑manganese binary oxide nanoparticles on nylon 6 fibre for rapid and continuous arsenic [As(III)] removal from drinking water

Arsenic in drinking water causes serious health problems and must be brought below the permissible 10 ppb limit rapidly, for on-spot remediation. Household reverse osmosis (RO) units remove As(III) partially. To address this, a post-RO adsorbent is developed based on iron‑manganese binary oxide nanoparticles (IMBNP) impregnated nylon 6 fibre (IMBNP-nylon 6). By optimizing H2SO4 concentration and by reducing temperatures of both IMBNP impregnation and subsequent vacuum drying, IMBNP size on fibre surface could be reduced from 320 to 75 nm. This resulted in increased IMBNP loading on the fibre from 1.4 to 9.3–10 wt%, giving a high adsorption capacity of 48.7 mg As(III)/g of IMBNP-nylon 6 fibre. IMBNP has a synergistic role here, since its MnO2 component oxidises As(III) to As(V), which is more effectively adsorbed by its Fe2O3 component; this in contrast to poor adsorption of As(III), when only Fe2O3 is used. The IMBNP-nylon 6 composite, in continuous fixed bed experiments with feed water of 100 ppb As(III), facilitates removal of arsenic below 10 ppb level, with only 39 s contact time. Overall, this work demonstrates the potential scalability of this technique to treat a large amount of arsenic-containing permeate water in household RO units.

Excess energy recovery from a stand-alone PV system for freshwater production using RO unit: Techno-economic analysis

A techno-economic assessment of electricity and freshwater cogeneration system powered by a standalone solar PV system is investigated under weather conditions of Al-Khobar City, Kingdom of Saudi Arabia. The excess electricity generated by the PV system is used to operate Reverse Osmosis (RO) desalination unit using three alternative storage types: Battery, Water-Tank, and hybrid Battery/Water-Tank storage system. The RO desalination plant is mathematically modeled, and its hourly specific energy consumption is predicted by taking into consideration variations in pressure and temperature for one full year using Engineering Equation Solver (EES) software. Then, a MATLAB code is developed and used to optimize the PV array with the three alternative storage options. A novel indicator called the Shortage of Water Supply Probability (SWSP) is introduced and used to optimize the storage size and to ensure satisfying water demand. Results showed that the lowest levelized cost of water (LCW = 1.874 $/m3) is obtained when operating the RO desalination plant with a hybrid Battery/Water-Tank storage system. However, LCW is 2.892 and 2.647 $/m3 when battery or water-tank storage systems are used, respectively. From an environmental point of view, utilizing renewable energy to run the cogeneration system saved 131 tons/year of CO2 emissions.

Optimal Sizing and Management of Hybrid Wind Turbine-Diesel-Battery System for Reverse Osmosis Seawater Desalination in NEOM City

Optimal sizing and management of hybrid wind turbine-diesel-battery system for reverse osmosis seawater desalination in NEOM city is the objective of the paper. Therefore, the paper explored the different factors to optimize and introduce a technoeconomic evaluation and energy management of a stand-alone wind turbine (WT) system, diesel generator (DG), and battery storage (BS). The suggested WT/DG/BS system is implemented to feed seawater reverse osmosis (SWRO) unit in NEOM. The necessitated desalinated water per day is 100 m3. To determine the optimal size of WT/DG/BS corresponding to the minimum cost of energy (COE) and net present cost, two different ratings of the SWRO units (SWRO-100 and SWRO-150), three control dispatch strategies (load following, cycle charging, and combined dispatch), and five types of batteries are considered. HOMER software is performed to simulate and optimize the WT/DG/BS. The optimization results indicated that the best battery storage is the Trojan SAGM battery. In this case, the COE ranged between $0.337/kWh and $0.564/kWh. The lowest COE of $0.377/kWh is obtained when using a combined control strategy and SWRO-100 unit, whereas the worst COE of $0.564/kWh is obtained when using load following control strategy and SWRO-150 unit. The best option of the WT/DG/BS system to supply the SWRO unit is option number 26. This system includes one wind turbine of 90 kW, DG of 25 kW, 47 Trojan SAGM batteries, a 23.8 kW converter, a SWRO-100 unit, and a combined control strategy. The net present cost and the initial cost are $950,725 and $221,495, respectively. The annual operating cost and annual consumed fuel are $56,409 and 36,396 L, respectively. Compared with using only a 25 kW diesel generator, the COE reduced from $0.373/kWh (using only DG/BS) to $0.337/kWh (using the best option) by around 9.65%. Under this condition, the values for the internal rate of return, return on investment, and simple payback are 11%, 7.8%, and 8.3 years, respectively.

Technical and financial feasibility of a chemicals recovery and energy and water production from a dairy wastewater treatment plant

Due to the high volume of wastewater produced from dairy factories, it is necessary to integrate a water recovery process with the treatment plant. Today, bipolar membrane electrodialysis units (BMEUs) are increasingly developed for wastewater treatment and reutilizing. This article aims to develop and evaluate (technical and cost analyses) a combined BMEU/batch reverse osmosis unit (BROU) process for the recovery of chemicals and water from the dairy wastewater plant. The combined BROU/BMEU process is able to simultaneously produce water and strong base-acid, and reduce power consumption due to the injection of concentrated feed flow into the BMEU. A comprehensive comparative analysis on the performances of two combined and stand-alone BMEU configurations are developed. The proposed combined technology for dairy factory wastewater treatment is designed on a new structure and configuration that can address superior cost analysis compared to similar technologies. Further, the optimal values of permeate flux and current density as two vital and influencing parameters on the performance of the studied dairy wastewater treatment process were calculated and discussed. From the outcomes, the total cost of production in the combined configuration has been reduced by approximately 26% compared to the stand-alone configuration. Increasing the feed concentration rate using the batch reverse osmosis process for the dairy wastewater treatment process can be an ideal solution from an economic point of view. Moreover, point (current density, feed concentration rate, total unit cost) = 328.9,7,14.37\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\left(328.9, 7, 14.37\\right)$$\\end{document} can be considered as an optimal point for the economic performance of the studied wastewater treatment process.

Treatment of anaerobically digested pig manure by applying membrane processes for nutrient recovery and antibiotics removal.

A combination of membrane processes was applied to treat the digestate produced after the anaerobic treatment of pig manure in a biogas plant, aiming towards the recovery of nutrients and effective water treatment for potential reuse. Initially, coarse filtration (sieving and microfiltration) was used to remove particles larger than 1 µm, followed by ultrafiltration, to reduce the suspended solids concentrations below 1g/L. Subsequently, selective electrodialysis is employed to recover the main nutrient ions, primarily ammonium and potassium. The ion-depleted digestate is then fed to a reverse osmosis unit, where clean water was recovered, yielding a by-product (concentrate) stream enriched in phosphates and organics content. The presence of antibiotics and the concentrations of heavy metals were monitored during all treatment stages to assess their behavior/removal in the various membrane processes. The results indicate that almost 51% of the digestate could be recovered as water free from ions and antibiotics, suitable for reuse in the biogas plant for process needs and irrigation purposes. The selective electrodialysis process can recover 51% of initial NH4+ content (corresponding to 96% of the electrodialysis feed), while the remainder largely ended up in the ultrafiltration concentrate. A similar behavior was observed for the case of K+, while approximately 68% of the phosphates content was retained by the coarse filtration process, with another 24% remaining in the ultrafiltration concentrate and the remaining 8% in the reverse osmosis concentrate. Most of the antibiotics and heavy metals were retained by the coarse and ultrafiltration steps, with smaller amounts detected in the reverse osmosis concentrate.

Utilizing Hybrid RO-OARO Systems as New Methods for Desalination Process

The scarcity of fresh water and its essential role in sustaining life on Earth have motivated researchers to seek new, low-cost, scalable technologies for water desalination. Therefore, the osmotically assisted reverse osmosis (OARO) membrane process presents an innovative approach to achieve moderate water recoveries from high salinity water without undergoing a phase change. This work aims to investigate the performance of hybrid RO-OARO systems with various designs and operational parameters on recovery and R%. The hybrid systems were evaluated for 60 minutes at feed concentrations of 3.98-5.54 g/l, applied pressures ranging from 3 to 7 bars, and different membrane types. The results showed that the flux of the hybrid system increased by increasing the pressure and decreased by increasing the feed concentration. The highest recovery value was obtained for the RO-OARO system at an RO pressure of 7 bar and an OARO unit at 3 bar for a 3.98 g/l feed concentration. In contrast, when the reverse osmosis pressure was fixed at 5 bar, and the pressure of the OARO unit increased by 2 bar, the recovery value exceeded by about 6%. Furthermore, the FilmTech membrane showed the highest recovery at 31.7%, while the highest R% was 94.55% for the AquaTec membrane. The RO-OARO-OARO system contributed to increasing both the recovery and rejection values by 11.4 and 2.1%, respectively, compared with the RO-OARO system. The experiments in this study revealed a slight increase in the feed concentration of the reverse osmosis unit, indicating the efficiency of the hybrid systems compared to traditional RO systems.

Multistage membrane-integrated zero liquid discharge system for ultra-efficient resource recovery from steel industrial brine: Pilot-scale investigation and spatial membrane fouling

Zero liquid discharge (ZLD) strategy provides significant potential for industrial brine treatment. Still, the application has been constrained by the inadequate water recovery and membrane fouling of its membrane-based brine concentration system. Herein, a pilot-scale system was established that integrated pretreatment, reverse osmosis (RO), nanofiltration (NF), and disk tube reverse osmosis (DTRO), and demonstrated over a 6-month operation for the first application in treating steel industry brine. Meanwhile, novel insights were offered into the spatial evolution of DTRO membrane fouling. The overall ZLD system reached ultra-efficient water recovery at 91% with relatively low energy consumption (7.27 kWh/m3). The RO and NF units concentrated the brine and selectively separated ions of different valences, simultaneously eliminating various contaminants. The DTRO unit enriched the highly saline NF permeate with a remarkable 7.5-fold concentration effect, producing an extremely hypersaline brine salinity (138,472 ± 34,804 mg/L, Cl−/SO42− mass ratio of 56) that ultimately yielded ultra-pure NaCl salt. Additionally, DTRO special fouling patterns revealed a distinctive "W"-shaped fluctuation in humic acid along the device water flow, with concurrent reduction in iron/aluminum oxides leading to their deposition at the outlet. This synergistic fouling, coupled with silicon, coincides with the transformation of silica colloids into silicate compounds. The multistage membrane-based strategy and the spatial membrane fouling evolution pattern proposed and investigated in this work provide a highly efficient and cost-effective solution for industrial brine treatment with ZLD.

3-Dimensional CFD Simulation of Pre-Wastewater Treatment via Multi-Channel Porous Ceramic Membrane

Multi-channel microfiltration (MF) membranes are considered as one of the most efficient separation methods for wastewater treatment, mainly due to their relatively high thermal and chemical resistance. Among various types of MF membranes, Ceramic Membranes attract great attention because of their high active area and superb mechanical strength, making them an industrially applicable pretreatment process for Reverse Osmosis (RO) unit operation. Here, a thorough 3-dimensional modeling of a 19-channel Ceramic Membrane was employed in order to gain insight into pressure drop, velocity distribution, and concentration profile in each channel. Experimental data from a lab-scale multi-channel Ceramic Membrane fed with oily wastewater was used to validate the model. The permeate flux was predicted as 200 to 250 L/m2.hr based on the porous media transmission pressure in such configurations. Further, permeate mass flux was also calculated based on the inlet flow velocities ranging from 0.75 to 2.25 m/s.

Experimental study of a booster pump-free isobaric energy recovery device (DAC) for reverse osmosis: Performance evaluation and comparison

Reverse osmosis (RO) is a widely used desalination technology known for its high energy requirements. However, the incorporation of energy recovery devices (ERDs) in RO plants has proven effective in reducing specific energy consumption. The booster pump (BP) is an essential component utilized in conjunction with isobaric ERDs. Approximately 5 to 10 % of the capital cost for small to medium-sized RO units is attributed to the BP. The objective of this paper is to investigate the feasibility of implementing a newly designed isobaric ERD called DAC. The study focuses on an RO plant with a capacity of 48 m3/day. The proposed ERD undergoes design, manufacturing, and experimental testing. The major benefit is its ability to utilize the system feed pump as a BP, eliminating the need for a separate BP. This equipment reduction not only lowers the initial cost but also simplifies the system complexity. Furthermore, the system is designed to allow a comparison between the DAC and a pressure exchanger (PX) under the same operating conditions. However, unlike the DAC, the PX becomes unresponsive and does not function when the BP is turned off to allow the system feed pump to take over.