Brackish Water Reverse Osmosis Desalination Research Articles

Smart system management and techno‐environmental optimal sizing of a desalination plant powered by renewables with energy storage

The present study assessed the performances of a brackish water reverse osmosis desalination unit powered by (PV/Wind/Battery) system with hydraulic storage. The hybrid renewable energy system and the reverse osmosis desalination plant were modeled for a specific site in southern Tunisia using real meteorological and water consumption data for 1 year. A total of 8760 simulations were treated under a dynamic simulator coupled to a smart energy management strategy to reach the hourly water load demand. Although the recognized reliability of the hybrid renewable sources compared to one- power source, their design may still critical. Therefore, in this paper, the authors suggest applying the methodology of optimizing the presented unit using an integrated systemic meta-modeling which is built through the design of experiments tool and defined by an equation involving the decision variables of the optimization as its parameters. This equation outlines the objects of the optimum sizing. The selected optimal design of the proposed unit is predicted by the genetic algorithm NSGA-II based on minimizing two objectives in conflict: Embodied energy and hydraulic loss of power supply. The CPU time of the NSGA-II optimization via the meta-model reached only 15 minutes of treatment (with one day to build the design of experiments) compared to the classic optimization via dynamic simulation. The results of the optimum sizing show that it is possible to consider a low water shortage rate (0% ⩽ LPSP-H < 5%) for a marginal variation of embodied energy rate which does not exceed (7%).

Energy, exergy, exergoeconomic, and environmental (4E) and carbon footprint analysis of coupling the various energy recovery devices with seawater and brackish water reverse osmosis desalination

Energy, exergy, exergoeconomic, and environmental (4E) and carbon footprint analysis of coupling the various energy recovery devices with seawater and brackish water reverse osmosis desalination

Novel Dynamic Designs for Ultra-High Recovery Waste and Brackish Water RO Desalination

Novel Dynamic Designs for Ultra-High Recovery Waste and Brackish Water RO Desalination

Systemic design and energy management of a standalone battery-less PV/Wind driven brackish water reverse osmosis desalination system

This work investigates a small-scale reverse osmosis desalination system dedicated for off-grid communities lacking freshwater. This system, constituted of motor-pumps, desalination process and hydraulic network (pipes and valves), is powered by hybrid photovoltaic-wind turbine source. It exploits hydraulic storage in water tanks filled when renewable energy is available instead of electrochemical storage. Such specificity makes the power/freshwater supply a challenging issue for these communities. To maximize freshwater production of this autonomous system, a “systemic design approach” integrating couplings between architecture, sizing, and energy management is proposed. According to the specific system architecture and its component sizing, a specific quasi-static model-based energy management strategy (EMS) is developed. In this regard, the influence of the main component sizing on the system energy efficiency and the EMS performance is analyzed. This study proved the strongly coupling between power/water management and pump sizing. According to the iterative process of the systemic design approach, simulation results showed that the EMS objective is reached by increasing the brackish water storage tank capacity and improving the system energy efficiency. The latter is achieved by choosing the pumps-combination composed of three pumps having the lowest rated powers (0.37 kW/0.37 kW/1.5 kW), but offering higher energy efficiency over other analyzed pumps-combinations.

Long-term intermittent operation of a full-scale BWRO desalination plant

The use of renewable energy sources (RES) to power reverse osmosis (RO) desalination plants is a promising option for remote communities that face water scarcity. One drawback, however, is that the plants are generally obliged to operate intermittently due to the nature of the RES, which can reduce RO system performance in terms of production, salt rejection and energy consumption. This work analyses the long-term performance of a full-scale brackish water reverse osmosis (BWRO) desalination plant that has been working under intermittent operating conditions for 14 years (~9 h d−1). The plant has two stages, a 2:1 arrangement and five spiral wound membrane elements per pressure vessel (Filmtec™BW30-400). The feed water is pumped from a groundwater well. The feed flow and water flux recovery remained practically constant (416 m3 d−1 and around 65% respectively) over the 14-year period. The plant uses antiscalant dosing (5 mg L−1) and two cartridge filters in series (25 and 5 μm) as a pre-treatment. Rinses are carried out before shut-downs. Feedwater conductivity, permeate conductivity, feed pressure, pressure drop, permeate flow, and feed flow operating data were collected. The results show a decrease of about 50% in the average water permeability coefficient and an increase in specific energy consumption from 1.82 to 2.21 kWh m−3. The results provide useful information about the behavior of BWRO desalination systems under intermittent operating conditions and should be taken into account when designing RES-powered BWRO desalination plants.

Performance evaluation of reverse osmosis brackish water desalination plant with different recycled ratios of retentate

Reverse Osmosis (RO) process has become one of the most widely utilised technologies for brackish water desalination for its capabilities of producing high-quality water. This paper emphasis on investigating the feasibility of implementing the retentate recycle design on the original design of an industrial medium-sized multistage and multi-pass spiral wound brackish water RO desalination plant (1200 m³/day) of Arab Potash Company (APC) located in Jordan. Specifically, this research explores the impact of recycling the high salinity stream of the 1st pass (at different recycled percentages) to the feed stream on the process performance indicators include, the fresh water salinity, overall recovery rate, and specific energy consumption. The simulation is carried out using an earlier model developed by the same authors for the specified RO plant using gPROMS suits. This confirmed the possibility of increasing the product capacity by around 3% with 100% recycle percentage of the high salinity retentate stream.

Evaluation and minimisation of energy consumption in a medium-scale reverse osmosis brackish water desalination plant

The Reverse Osmosis (RO) process has been expansively used in water treatment as a result of its low energy consumption compared to thermal distillation processes, leading to reduced overall water production cost. Evaluation and minimisation of energy consumption (expressed in kWh/m3 of fresh water production) in a medium-scale spiral wound brackish water RO (BWRO) desalination plant of the Arab Potash Company (APC) are the main aims of this research. The model developed earlier by the authors has been integrated to simulate the process and achieve the main aims. Energy consumption calculations of low salinity BWRO desalination plant, with and without an energy recovery device, have been carried out using the gPROMS software suite. In other words, this research evaluated the impact of adding an energy recovery device on the RO process energy consumption of the APC, which is introduced for the first time. Also, the effects of several operating conditions of BWRO process include the feed flow rate, pressure and temperature on the performance indicators, which include the energy consumption and total plant recovery at different energy recovery device efficiencies, were studied. The simulation results showed that the total energy consumption could be reduced at low values of feed flow rates and pressures and high values of temperatures. More importantly, there is an opportunity to reduce the total energy consumption between 47% and 53.8% compared to the one calculated for the original design without an energy recovery device.

Demineralization of brackish surface water by reverse osmosis: The first experience in Morocco

Desalination technique is among the focused theme of the Moroccan kingdom’s universities. The implementation of reverse osmosis (RO) technology at the industrial level has proved that this RO technology delivers an affordable production of good water quality and quantity. The conception of mid-size to large RO (FILMTEC™ product) desalination plants are performed by means of reverse osmosis system analysis (ROSA) software. This study shed the light on how realistic the predictions are done by means of ROSA software to the real daily performance of the RO (FILMTEC™XLE440) membranes. The results obtained are then compared against the real industrial data collected from Khenifra desalination plant. This RO plant is designed to produce 36.290 m3/d of drinking water at the horizon of the year 2030. The performances collected are the pressure, temperature, permeate flow and permeate conductivity. The brackish water RO desalination plant has operated successfully and showed a steady behavior from the second half of 2013. The data collected within around 400 days showed that the ROSA modeling prediction matches in a conservative way to the real performance data collected from the plant at about 97%.

Retrofitting assessment of a full-scale brackish water reverse osmosis desalination plant with a feed capacity of 600 m3/d

Retrofitting assessment of a full-scale brackish water reverse osmosis desalination plant with a feed capacity of 600 m3/d

Phenomenological prediction of desalination brines nanofiltration through the indirect determination of zeta potential

Abstract The prediction of nanofiltration (NF) performance at environmentally relevant conditions, e.g.: highly saline brine solutions, is becoming of increasing interest for the recovery of waste materials in the water desalination industry. In this work, the prediction of the separation of sulfate and chloride contained in the retentate of reverse osmosis brackish water desalination by means of the commercial NF270 membrane is studied. Prior to theoretical modelling, streaming potential measurements were performed for aqueous single and binary mixtures of NaCl and Na2SO4 within the range of ionic strengths 1–100 mol/m3. Zeta potential values were obtained applying an extrapolation method from recent literature to allow the calculation of surface charge density under higher ionic strengths found in reverse osmosis desalination brines (100–1200 mol/m3). Then, the obtained surface charge density was used to simulate sulfate, chloride and sodium rejections by means of the Donnan steric pore model (DSPM), in the pressure range 2–20 bar. The good agreement between experimental and simulated rejection values allows validating the approach that enables the prediction of NF performance for the separation of monovalent and divalent anions, of interest for the purification of desalination brines before their further exploitation as a source of sodium chloride concentrated solutions.

Performance analysis of a medium-sized industrial reverse osmosis brackish water desalination plant

The implementation of Reverse Osmosis (RO) technology is noticeably increased to produce freshwater from brackish and seawater resources. In this work, performance analysis of a multistage multi pass medium-sized spiral wound brackish water RO (BWRO) desalination plant (1200 m3/day) of Arab Potash Company (APC) located in Jordan is evaluated using modelling and simulation. For this purpose, a mathematical model for the spiral wound RO process based on the principles of solution diffusion model is developed. The model is then used to simulate the operating conditions of low-salinity brackish water RO (BWRO) desalination plant. The results obtained are then compared against the real industrial data of BWRO desalination plant of APC which shows a high-level of consistency. Finally, the model is used to analyse the impact of the operating parameters such as salinity, pressure, temperature, and flow rate on the plant performance. The sensitivity analysis confirms that both feed flow rate and operating pressure as the critical parameters that positively affect the product salinity.

Techno-Economic Study of PV Powered Brackish Water Reverse Osmosis Desalination Plant in the Jordan Valley

Jordan is one of the ten most water scarce countries in the world. In 2014, the share of water per capita per year in Jordan is 120 Cubic Meters (m3 ). The water deficit is estimated to be 160 Million Cubic Meter (MCM) in 2015. This deficit is projected to grow up to 490 MCM by 2025. This study discusses the possibility of using solar energy for brackish water desalination in Jordan Valley (JV) to reduce the pressure on the fresh water and the conventional energy consumption associated with the desalination process, as well as, to reduce Greenhouse Gases (GHG) emissions associated with the consumption of energy produced from fossil fuels. Photovoltaic (PV) powered brackish water reverse osmosis desalination technology (RO) has been investigated in this study. The PV system has designed using PVSOL software. The economic feasibility study of use PV system has been done using Average Incremental Cost of Water (AICOW), Internal Rate of Return (IRR) and Net Present Value (NPV) in several scenarios. The results of the analysis showed that using PV systems for brackish water desalination for a small size single plant at current electricity tariff is not economically feasible for the farmers. But it is feasible for a larger size plant for ten farms or more, or with financial support from the government. The feasibility results showed that using PV systems for brackish water desalination for the government side are economically feasible even for a small size plant.

Multi objective optimization of reverse osmosis desalination plant with exergy approach

A brackish water reverse osmosis desalination plant based on exergy analysis was simulated and its performance was investigated. The computational model base on diffusion and convection transport mechanisms and concentration polarization concept was developed to predict the performance of RO membrane using different feed water concentration, feed flow rate, feed water pressure, membrane specification and feed water properties. The mathematical model has had good accuracy with reference data. The influence of operating parameters such as feed water pressure and temperature on the performance of the system was studied. Exergetic efficiency and destruction of streams exergy were calculated. Finally, multi-objective optimization for highest exergetic efficiency and permeate flow rate was done.

Long-term performance decline in a brackish water reverse osmosis desalination plant. Predictive model for the water permeability coefficient

Transport models in reverse osmosis (RO) desalination have been extensively studied taking into account various factors such as temperature, fouling, etc. However, there are not many models that describe the behavior of a desalination plant over long time periods. These models depend on operating time and empirical parameters to estimate the flux or the average water permeability coefficient (A) decline. The proposed model separates the decline of A in two stages, the first stage refers to a more pronounced decline due to initial compaction and irreversible fouling and the second stage describes a more stable period with less slope. The model is based on the superposition of two exponential functions, which depends on operating time, empirical parameters and fouling potential of the feedwater (kfp). Ten years operating data of a brackish water reverse osmosis (BWRO) desalination plant were used. The obtained results with the proposed model showed a slightly better fit than previous models, but giving meaning to two different behaviors separated in two stages.

Design and experimental performance of brackish water reverse osmosis desalination unit powered by 2 kW photovoltaic system

Small-scale brackish water reverse osmosis (BWRO) desalination units are not a major commercial success compared to its large-scale counterpart. Integrating renewable power systems with small-scale units would theoretically aid in their deployment and subsequent commercial success. In fact, RO units are constructed using a modular approach; this would allow them to adapt to a renewable power supply. Small-scale PV-RO would be a promising form of desalination system in remote areas, where BW is more common. The aim of this study is to quantify the effect of climatic-design-operation conditions on the performance and durability of a PV-BWRO desalination system. A small-scale unit is designed, constructed, and tested for 6 months. The design was limited to a 2 kWp PV power system, five different membranes, a feed TDS of 2000 mg/l, and a permeate TDS of less than 50 mg/l. Data pertaining to solar radiation and temperature were subsequently analyzed to determine their respective influences on current and future operations of the unit. The results showed that the optimum RO load, membrane type, and design configuration were 600 W, (4″x40″ TW30-4040), and a two-stage configuration, respectively. The PV system was able to supply the load without any significant disturbances; while the RO unit showed stable levels of permeate flow and salinity. Operating the PV-BWRO system for 10 h during the day would produce 5.1 m3 of fresh water at a specific energy of 1.1 kWh/m3. It was confirmed that there are many hours of high temperatures during the operation of the PV module (exceeding 45 °C) and battery room conditions (exceeding 35 °C), both of which could negatively affect the power output and battery autonomy. This negative effect is compounded annually; therefore, optimizing thermal regulation of PV modules and battery bank room conditions is essential in maintaining excellent operating temperatures.

Start-up of brackish water desalination for agricultural irrigation in the Canary Islands (Spain)

The Canary Islands are an arid region. Therefore, water resources are scarce and several islands depend strongly on the sea and brackish water desalination. Water desalination, in the water policy of the Canary Islands, has been deeply rooted in the last 40 years, allowing solving and overcoming the shortage. This article concerns the beginning of the brackish water desalination for agricultural purposes in the Canary Islands (Spain). It provides the data and experience acquired during the early years in the region; one of the authors of this paper was working in the department of desalination of the first companies in the Canary Islands like Riegocan, AM García Glez. and Temkon. These companies worked with membrane manufacturers like Fluid System, Filmtec and Desalination Systems and pressure pipe manufacturer—Advanced Structures. Fifteen brackish water reverse osmosis desalination plants were built in the Canary Islands to provide water for agricultural irrigation between 1979 and 1983. These plants had a significant impact on agriculture.

Exergetic analysis of a brackish water reverse osmosis desalination unit with various energy recovery systems

Exergetic analysis of a reverse osmosis desalination unit is performed for brackish water feed using different energy recovery methods. This includes single and two-stage pressure retarded osmosis units (for infinite area). The correct definition of exergetic efficiency for such systems is also discussed. A clear connection is seen between specific energy consumption and the efficiency definition chosen such that one can be determined from the other. The program written is validated against experimental and numerical data from the literature with nearly zero percent error. The effect of salinity, turbine and pump efficiency as well as mass ratio is studied. In all cases, it is seen that the reverse osmosis unit has the best efficiency when a pressure exchanger is used as an energy recovery device (∼16% maximum). All pressure retarded osmosis options investigated had efficiencies below or approximately equal to the hydro-turbine. Since finite area and concentration polarization would further decrease the efficiency, therefore, it does not seem to be a viable energy recovery method for reverse osmosis units with brackish water feed.

80,000 h operational experience and performance analysis of a brackish water reverse osmosis desalination plant. Assessment of membrane replacement cost

The brackish water reverse osmosis (BWRO) desalination plant has operated successfully for around 80,000h from 2004. Reverse osmosis membrane technology has improved allowing higher salt rejection, permeate water productivity and durability. But when the membranes should be replaced taking into account the energy consumption increase. The aim of this paper is to assess the operating information available and energy consumption to evaluate when it would be appropriate to replace the membranes taking especially into account the long life elements involved. The graphical evolution of feedwater conductivity, permeate conductivity, feed pressure, pressure drop, specific energy consumption (SEC) and the standardization of the permeate flow, salt rejection and SEC are shown. A comparison between specific energy consumption increase due to membrane performance decay, the regularity of chemical cleaning and membrane replacement in terms of costs has been carried out. The results show that the most effective choice for this BWRO desalination plant is not to replace the membranes in the first ten years of operation taking into account the membranes performance and the cost of electricity at the time.

A design method of the RO system in reverse osmosis brackish water desalination plants (calculations and simulations)

This paper proposes a simple design method of the RO system in RO brackish water desalination plants. This method is based on the application of maximum available recovery without scaling of any of the compounds present in the water as silica, calcium carbonate, calcium sulfate, barium sulfate, strontium sulfate, and calcium fluoride, and membrane manufacturer design guidelines, and the plant production. It is a continuation of the paper “A design method of the RO system in reverse osmosis brackish water desalination plants (procedure)” presented at the conference on Membranes in Drinking and Industrial Water Production, Leeuwarden, The Netherlands, 10–12 September 2012. Although the method was originally conceived for application to subterranean brackish waters in the Canary Islands, Spain (principally Gran Canaria, Fuerteventura and Tenerife), it can be extrapolated to other types of region and water treatable with RO systems. The required input data are the chemical composition of the feed water, pH, temperature, SDI, membrane manufacturer design guidelines, and the plant production. The programmed method determines the design of the RO system (arrangement) and the operating pressure so as the quality of the product water for different operating years and different types of the RO elements. The method whose procedure is described graphically and analytically can be used as an aid in design optimization of RO brackish water desalination plants with acid-free pre-treatment processes and by the use of scale inhibitor using spiral wound membranes. Practical applications are presented. Calculations and simulations for different types of feed water and capacities are showed. A comparison between the values obtained by this method and from membranes manufacturer software is shown so as the comparison between these and the real values from different desalination plants.

Carbon footprint of water reuse and desalination: a review of greenhouse gas emissions and estimation tools

As population and water demand increase, there is a growing need for alternative water supplies from water reuse and desalination systems. These systems are beneficial to water augmentation; however, there are concerns related to their carbon footprint. This study compiles the reported carbon footprint of these systems from existing literature, recognizes general trends of carbon footprint of water reuse and desalination, and identifies challenges associated with comparing the carbon footprint. Furthermore, limitations, challenges, knowledge gaps, and recommendations associated with carbon footprint estimation tools are presented. Reverse osmosis (RO) technologies were found to have lower CO2 emissions than thermal desalination technologies and the estimated carbon footprint of seawater RO desalination (0.4–6.7 kg CO2eq/m3) is generally larger than brackish water RO desalination (0.4–2.5 kg CO2eq/m3) and water reuse systems (0.1–2.4 kg CO2eq/m3). The large range of reported values is due to variability in location, technologies, life cycle stages, parameters considered, and estimation tools, which were identified as major challenges to making accurate comparisons. Carbon footprint estimation tools could be improved by separating emissions by unit process, direct and indirect emissions, and considering the offset potential of various resource recovery strategies.