Membrane Desalination Technology Research Articles

In-line granular filtration for mitigating gypsum scaling in membrane distillation

Mineral scaling and scaling-induced wetting are major challenges for the widespread application of membrane distillation (MD) in saline wastewater treatment. For the first time, an in-line modified activated alumina (AA) granular filtration coupled with MD process was proposed to achieve effective control of gypsum scaling. Firstly, the AA modified by NaOH impregnation with tuned pore structure and surface characteristics were supplied as the filter media. The optimized MD performance was obtained using in-line filtration with modified AA (MAA) with 20 g/L NaOH and the ratio of AA and NaOH solution of 1:3 for the duration of 24 h. Compared with severe scaling without granular filter, the optimized performance with a final normalized flux higher than 0.7 and a permeate conductivity less than 5 μS/cm at 70 % water recovery was observed. The MAA with rich pore, scale-like structures and high Na loading showed a superior ability in capturing gypsum scaling due to the enhanced heterogeneous scaling and the retention of scaling. In-line granular filtration-MD was also effective in mitigating gypsum scaling and scaling-induced wetting in saline solutions (e.g., 7–12 g/L NaCl). Our findings provide guidance for surface design of granular filter media and scaling control in membrane desalination technology.

Integration of capacitive deionization and forward osmosis for high water recovery and ultrapure water production: concept, modelling and performance analysis

ABSTRACT Forward Osmosis (FO), a membrane desalination technology and Capacitive Deionization (CDI), an electrically operated desalination technology, are numerically integrated utilizing four different configurations for the high-water recovery rate and ultrapure water production from brackish water resource. To minimize the wastewater rejection, the CDI desorption stream is continuously fed to the FO unit, efficiently recovering the remaining freshwater. To produce ultrapure water, freshwater stream obtained from FO is provided to the CDI cell, which adsorbs the remaining dissolved solute particles. These two configurations serve the purpose of both industrial as well as domestic water supply requirements. Continuing this concept, the formation of the other two configurations allows us to obtain fresh water and ultrapure water simultaneously and up to a 90% freshwater recovery rate for the areas with inadequate supply. The performance parameters to assess the integration are the Water Recovery Rate (WRR) and Specific Energy Consumption (SEC). The first configuration (CDI-FO), proposed for a high freshwater recovery rate, resulted in 79.33% WRR with an SEC of 0.689 kWh / m 3 . While, for the second configuration (FO-CDI), 34.25% water was recovered as 2.87 ppm ultrapure water along with 34.25% freshwater. The third proposed configuration (CDI-FO-CDI) had a WRR of 79.33%, 14.67% of which was recovered as ultrapure water of concentration 2.86 ppm. The fourth configuration (CDI-FO-FO) developed for high water recovery, removed the maximum of water from the feed stream with a WRR of 91.33% and remained energy-efficient, consuming an SEC of 0.908 kWh / m 3 .

Interfacial polymerization layer with CNT providing fast water channels under electric field for efficient desalination of nanofiltration membranes

In order to solve the contradiction between permeability flux and selectivity in nanofiltration membrane desalination technology, a novel interfacial polymerization layer structure was designed. In this structure, the hydrophilic modified carbon nanotubes (CNT) untangled and protruded the PA layer under the electric field, resulting in the generation of microporous water channels between CNT and polyamide molecules. Thanks to this unique membrane surface structure, the permeability of the nanofiltration membrane was significantly enhanced, reaching 24.4 L·m−2·h−1·bar−1, in which the rejection of MgCl2 and Na2SO4 were also maintained at 96.1 % and 97.3 %, respectively. At the same time, the surface of the nanofiltration membrane remained intact in the chlorine resistance test, and the total fouling rate caused by lysozyme (LYZ) protein solution was only 2.89 %, demonstrating excellent chlorine resistance and pollution resistance. The design of changing surface structure through electric field-assisted nanomaterials provides a new innovative strategy for the development of separation membrane.

Delineation of the diamine monomers effect on the desalination properties of polyamide thin film composite membranes: Experimental and molecular dynamics simulation

The success of membrane desalination technology hinges on the properties of thin film composite (TFC) membrane that is commonly fabricated by interfacial polymerization (IP) of diamine and acyl chloride. The current study aimed to investigate the impact of the length of the alkyl side chain of the diamine monomers on the desalination performance of the TFC membranes. Four diamines (piperazine (PIP), 1-(2-aminoethyl)piperazine (EAP), 1,4-Bis(3-aminoprpyl)piperazine (DAPP), and m-xylylenediamine (XLN)) were used to fabricate four different TFC membranes with trimesoyl chloride (TMC) as a crosslinker. The merits of the TFC membranes were thoroughly characterized and the PIP was found to be advantageous compared to other diamines with different aliphatic alkyl chain lengths. Molecular dynamics simulations showed that PIP TFC membrane has a tight pore diameter of 1.1 nm and polar carboxylic groups within its pores, which makes it strongly hydrophilic reporting a water contact angle of 28°. The salt rejection (%) of the PIP TFC membrane followed the order: MgSO4 (91%) > Na2SO4 (85%) > Na2CO3 (77%) > NaCl (32%). The increase in feed pressure, temperature or velocity had a positive impact on the permeate flux. However, salt rejection deteriorated as the temperature of the feed increased.

Comparative techno-economic assessment of osmotically-assisted reverse osmosis and batch-operated vacuum-air-gap membrane distillation for high-salinity water desalination

New developments in pressure- and thermally driven membrane desalination technologies offer the potential to cost-effectively treat high-salinity waters, especially when powered by low-cost solar electricity and thermal energy. This paper presents a comparative techno-economic assessment of the state-of-the-art most promising pressure- and thermally driven membrane technologies for high recovery desalination, namely, osmotically-assisted reverse osmosis (OARO) and batch-operated vacuum-air-gap membrane distillation (batch V-AGMD), to produce potable water while concentrating brine within the range of 140–290 g/L TDS for minimum-liquid-discharge (MLD) and zero-liquid-discharge (ZLD) applications. It is shown that both OARO and batch V-AGMD can treat feedwater and brines with TDS in the range of 30–125 g/L with corresponding fresh water recovery rates of 85–25%. When low cost solar electricity and thermal energy are used, the resulting levelized cost of water (LCOW) from OARO is in the range of 0.70–6.28 $/m3, and that from batch-V-AGMD is in the range of 1.74–2.77 $/m3. OARO is more cost-effective than batch V-AGMD when feedwater salinity is below 70 g/L and recovery below 75%, whereas batch V-AGMD is more cost-effective at higher recovery rates and salinity levels. The sensitivity of this comparison on energy prices and module costs is discussed.

Elucidating the Effect of Aliphatic Molecular Plugs on Ion-Rejecting Properties of Polyamide Membranes.

Polyamide RO membranes are widely used for seawater desalination owing to their high salt rejection and water permeability; however, improved selectivity-permeability trade-off is still desired. "Molecular plugs," small molecules immobilized within the polyamide structure, offer an attractive approach; however, their overall effect on polyamide physicochemical properties poses many questions. Here, we analyze the effect of decylamine, a promising plug, and a few charged and uncharged mimics on polyamide films using several in situ techniques. Electrochemical impedance spectroscopy (EIS) reveals a complex pH-dependent response, whereby, upon exposure to amine solution, conductivity first rapidly drops; however, under alkaline conditions, when amine is uncharged, the trend subsequently slowly reverses, and conductivity increases. This slow reversal was observed for noncharged alcohols of similar size as well, but not for larger surfactant molecules. The reversal was assigned to the uptake of plug molecules within polyamide, as opposed to the fast initial drop assigned to surface adsorption. EIS and quartz-crystal microbalance (QCM) results showed that exposure to decylamine under alkaline conditions ultimately led to an irreversible decrease in conductivity, that is, stronger ion rejection, remaining after re-exposure of polyamide to amine-free buffer. This suggests that plug uptake within polyamide resulted in polymer stress, indeed observed in surface stress measurements, and subsequent relaxation. The results indicate that the moderate size of decylamine and conditions minimizing its charge were optimal for irreversible change; however, charge interactions helped maximize its binding within polymer and induce the desired sustained change in selectivity. The results have many potential implications for improving current membrane desalination technology and increasing inherent membrane selectivity toward hard-to-remove species.

Fabrication and characterization of high-performance forward-osmosis membrane by introducing manganese oxide incited graphene quantum dots

Forward osmosis (FO) is the futuristic membrane desalination technology as it transcends the disadvantages of other pressure-driven techniques. But, there still remain critical challenges like fabrication of highly permeable membrane with ideal structures maintaining high rejection rates that need to be addressed for implementation as a practical technology. In this work, novel thin-film composite (TFC) membranes were fabricated by means of incorporating manganese oxide (MnO2) incited graphene quantum dots (GQDs) nanocomposite into a cellulose acetate (CA) suspension followed by phase inversion (PI) for enhanced FO performance. The surface morphology and chemical structure of fabricated membranes were studied using various characterization techniques like XRD, FT-IR, SEM-EDS, Mapping, AFM, and TGA. The structural parameters, water flux, reverse salt flux and salt rejection was estimated on the basis of data obtained from four varying initial draw solution concentrations. At high nanocomposites stacking, the hydrophilicity of the casting blend increase, and subsequently, the PI exchange rate additionally increases, which brings about noticeable difference in the surface morphology. The membrane with 0.5 wt% nanocomposite exhibited superior FO separation performance with osmotic water flux of 18.89, 34.49, 41.76 and 42.34 in L.m−2.h−1 with variable concentrations of NaCl salt solution (0.25M, 0.5M, 1M, and 2M), respectively. Also, the porosity of the membrane was increased to 47.23% with 96.87% salt rejection. The results indicate that the hydrophilicity of the nanocomposite drives them to the interface among CA and water during PI process leading to solid hydrogen bonding to achieve high water permeability.

Energy, exergy and exergoeconomic (3E) analysis and multi-objective optimization of a closed-circuit desalination system with side-conduit

Membrane desalination technologies such as reverse osmosis (RO) are being widely used around the world to deal with the growing freshwater shortage. In addition, the use of new reverse osmosis technologies that improve the performance of traditional ones, has received more attention. The main problem in desalination plants is the high total specific energy consumption as well as high capital investment, maintenance and repair costs. In this study, the performance of a new closed-circuit reverse osmosis (CCRO) desalination system with side-conduit as a replacement for energy recovery device, is investigated based on energy, exergy and exergoeconomic (3E) analysis. 3E analysis is performed based on four important factors including 1) concentration of inlet feed water 2) number of cycles 3) osmotic pressure 4) mass flow rate of feed water. Then, using the output data obtained from 3E analysis, the optimal points for six key parameters of exergy efficiency, net driving pressure (NDP), total unit cost product (SUCP), mass flow rate of permeate, recovery ratio and specific energy are determined through multi-objective optimization. The simulation results show that in the proposed system, by increasing the number of cycles, the recovery ratio increases while the system costs also increase due to increase in pressure and concentration of inlet feed. It is found that the optimal recovery ratio of 64.29% is obtained for 9th cycle and inlet feed concentration of 6.95% and the optimal specific energy consumption of 2.5 kWh/m3 is obtained for 7th cycle and inlet feed concentration of 6.07%.

Partial Desalination of Saline Groundwater: Comparison of Nanofiltration, Reverse Osmosis and Membrane Capacitive Deionisation

Saline groundwater (SGW) is an alternative water resource. However, the concentration of sodium, chloride, sulphate, and nitrate in SGW usually exceeds the recommended guideline values for drinking water and irrigation. In this study, the partial desalination performance of three different concentrated SGWs were examined by pressure-driven membrane desalination technologies: nanofiltration (NF), brackish water reverse osmosis (BWRO), and seawater reverse osmosis (SWRO); in addition to one electrochemical-driven desalination technology: membrane capacitive deionisation (MCDI). The desalination performance was evaluated using the specific energy consumption (SEC) and water recovery, determined by experiments and simulations. The experimental results of this study show that the SEC for the desalination of SGW with a total dissolved solid (TDS) concentration of 1 g/L by MCDI and NF is similar and ranges between 0.2–0.4 kWh/m3 achieving a water recovery value of 35–70%. The lowest SECs for the desalination of SGW with a TDS concentration ≥2 g/L were determined by the use of BWRO and SWRO with 0.4–2.9 kWh/m3 for a water recovery of 40–66%. Even though the MCDI technique cannot compete with pressure-driven membrane desalination technologies at higher raw water salinities, this technology shows a high selectivity for nitrate and a high potential for flexible desalination applications.

Environmental impact of desalination processes: Mitigation and control strategies

Freshwater supplies are in shortage relative to the high demand for different human activities, making desalination of saline water a must. Desalination to extract water from saline water has been well established as a reliable non-conventional water supply. However, desalination as any human-based process has resulted in many impacts on the environment. Brine loaded with chemicals being discharged back to the environment, along with greenhouse gases (GHGs) emissions being released to the atmosphere, are the most significant impacts, which has been extensively studied, with some efforts given to its mitigation and control.The current work discusses the mitigation and control strategies (M&CS) to the different environmental impacts (EIs) of desalination processes. The article compiles the M&CS in one work, instead of the distributed and separate treatment of the EIs of each desalination step and its respective M&CS as currently present in literature. The article tracks the water flow in an intake-to-outfall approach exploring how to minimize the impacts at each step and as a whole process. This starts from intake, pretreatment processes, desalination technology, and finally, brine discharge. The EIs associated with each desalination process element is thoroughly discussed with proposed M&CS. The work shows clearly that many EIs can be eliminated or minimized by incorporating specific design criteria and process improvements. The feedwater source has shown to have a great effect on EIs. Similarly, desalination technology has shown a considerable effect on the EIs related to brine characteristics and energy consumption. Hybrid and emerging desalination systems have shown reduced EIs relative to conventional thermal and membrane desalination technologies, while the utilization of renewable and waste energy sources has shown a significant reduction in EIs related to energy consumption.

A Molecular Dynamics Study on Rotational Nanofluid and Its Application to Desalination.

In this work, we systematically study a rotational nanofluidic device for reverse osmosis (RO) desalination by using large scale molecular dynamics modeling and simulation. Moreover, we have compared Molecular Dynamics simulation with fluid mechanics modeling. We have found that the pressure generated by the centrifugal motion of nanofluids can counterbalance the osmosis pressure developed from the concentration gradient, and hence provide a driving force to filtrate fresh water from salt water. Molecular Dynamics modeling of two different types of designs are performed and compared. Results indicate that this novel nanofluidic device is not only able to alleviate the fouling problem significantly, but it is also capable of maintaining high membrane permeability and energy efficiency. The angular velocity of the nanofluids within the device is investigated, and the critical angular velocity needed for the fluids to overcome the osmotic pressure is derived. Meanwhile, a maximal angular velocity value is also identified to avoid Taylor-Couette instability. The MD simulation results agree well with continuum modeling results obtained from fluid hydrodynamics theory, which provides a theoretical foundation for scaling up the proposed rotational osmosis device. Successful fabrication of such rotational RO membrane centrifuge may potentially revolutionize the membrane desalination technology by providing a fundamental solution to the water resource problem.

Membrane desalination technologies in water treatment: A review

Abstract One of the most pressing problems worldwide is inadequate access to potable water. Many technologies have been applied to address this through research to find robust but inexpensive methods of desalination that offer high fluxes and use less energy, while reducing chemical use and environmental impact. Membrane desalination technology is universally considered to solve water shortage problems due to its high efficiency and lower energy consumption than distillation methods. This review focuses on the desalination performance of membrane technologies with consideration of the effect of driving force, potential technologies, membrane types, flux, energy consumption and operating temperature, etc. Pressure driven membrane processes (MF, UF, NF, RO), and their fouling propensity and major drawbacks are discussed briefly. Membrane characteristics and the effects of operating conditions on desalination are also covered. Organic-hybrid and inorganic membrane materials can offer advantages, with high flux, good selectivity, and useful chemical and thermal resistance.

Performance analysis of thermal vapor compression integrated with reverse osmosis desalination system

Based on the thermal and membrane desalination technology, this study presents an analysis of an integrated single stage TVC-RO system. The hybrid system produces fresh water with an adjustable salinity in parallel operation. A steam ejector and a pressure exchanger are applied as the energy recovery devices. For comparison, a coupling system without energy recovery process is also modeled in the steady-state condition. System performance is evaluated by specific energy consumption and production ratio. The effects of several design parameters on system performance are investigated including boiling temperature, compression ratio, motive steam pressure, and target recovery rate. Results of the analysis indicate that the product salinity is adjustable in the TVC-RO system, and the system performance is largely dominated by system configurations and design parameters. To improve the system performance, the use of energy recovery device is necessary, and the membrane operation is recommended if the process is less demanding on product purity. A better performance can be obtained by increasing the target recovery rate of the RO membrane and decreasing compression ratio and motive steam pressure of the ejector. As the boiling temperature increases, one can expect that the production rate increases at a cost of a higher specific energy consumption.

Fabrication of efficient pervaporation desalination membrane by reinforcement of poly(vinyl alcohol)–silica film on porous polysulfone hollow fiber

ABSTRACTPervaporation membrane technology is commercially successful in the dehydration of organic solvents, and the technology has potential for seawater desalination with high recovery because of its capability to treat highly saline water. But to make the technology advantageous over the other available membrane desalination technologies in terms of productivity flux without additional energy cost, the selective barrier layer is required to be extremely thin, defect‐free, hydrophilic, and selective to water. In this work, we prepared an efficient membrane by reinforcing a highly water‐permeable but continuous barrier layer of poly(vinyl alcohol)–silica (PVA‐SiO2) hybrid material on porous polysulfone hollow fibers. The PVA‐SiO2 in acidified and hydrated ethanol was aged at room temperature for a period to allow solvent evaporation to obtain the solution concentration desired for the reinforcement. The reinforced hollow fiber membrane with optimal PVA‐SiO2 barrier layer thickness exhibited a performance with a flux of 20.6 L m−2 h−1 and 99.9% salt rejection from a saline feed of 2000 ppm NaCl at 333 K. The effects of PVA‐SiO2, temperature, and feed salinity on the pervaporation performance of the membrane were also studied. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45718.

Reverse osmosis desalination system and algal blooms Part I: harmful algal blooms (HABs) species and toxicity

Harmful algal blooms (HABs) are a serious concern in the countries surrounding the Arabian Gulf (AG). A recent HAB event (2008–2009) forced partial (or full) shutdown of desalination plants, and reduced their productivity. Strong fouling in filter media occurred, and frequent backwash was not sufficient to maintain their removal. Some plants were shut down for as much as 32–55 d—in places where water storage may only be a few days—when pretreatment processes struggled to remove the increased biomass caused by the HAB species, and were shut down before more irreversible fouling of the reverse osmosis (RO) membranes could occur. HAB challenges are not limited to the algal biomass that may foul membranes, but extend to the toxins that can pass through the membranes and find their way into finished water. Within the AG region, great care is given to the engineering part (operation and maintenance) under normal conditions of the seawater; however, challenges in all levels and scales emerge due to HAB incidents. This review article is the first part of three articles, focusing on the HAB identification and pretreatment technologies to deal with them. This part comprehensively focuses on the types of HAB species reported in AG seawater, physical conditions associated with HAB occurrence, morphology, taxonomy, and their potential impacts on desalination plants. The identification of the HAB species and their toxins is necessary to adopt the best pretreatment strategies to achieve the required feed water quantity and quality. As the AG countries are moving fast toward membrane desalination technologies to secure their municipal water requirements, they will need to adapt and deploy the technologies of HAB removal at very early stages of pretreatment.

Nanomaterials for biofouling and scaling mitigation of thin film composite membrane: A review

Biofouling and scaling are commonly encountered bottlenecks in large and small scale installations of membrane technology for surface-, waste- or seawater treatment. The phenomena can pose persistent operational challenge with substantial economic impacts if they are left unresolved. Effort has been made to reduce the tendency of these detrimental phenomena by improving membrane properties, optimizing operational conditions as well as establishing reliable pretreatment of the feed water. This review places a main focus on the recent advances of low biofouling and scaling thin film composite (TFC) membranes that are incorporated with different types of nanomaterials. In this contribution, the biofouling and scaling phenomena and their negative effects on TFC membranes are first discussed. The recent studies on the preparation of low biofouling and anti-scaling TFC membrane using different nanomaterials are then critically summarized. Current challenges to enhance membrane long-term stability, reliability, and cost efficiency are also highlighted. The applications of nanomaterials in membrane desalination are anticipated to improve resistance properties of TFC membranes against biofouling and scaling and further foster the innovation of sustainable membrane desalination technology.

Integration of Renewable Energy Technologies With Desalination

Remote communities in many countries are in need of dependable and affordable fresh water that must be derived from local brackish water or seawater. Thermal and membrane desalination technologies are available, with significant electrical or thermal energy requirements. Renewable energy from wind, solar, geothermal, or other sources may be necessary when access to grid electricity is limited. This literature review summarizes the research reported in the last three years (mid-2010 to mid-2013) by teams of experts in water treatment, renewable energy generation, variable-power system controls, system optimization, and economic analyses.

A novel implementation of water recovery from whey: “forward–reverse osmosis” integrated membrane system

As a result of its emerging contribution to water recovery and clean water production, forward osmosis (FO) in integrated membrane system has recently especially been preferred by research communities on membrane science and desalination technology. In this study, the effectiveness of FO reverse osmosis (RO) integrated membrane system in whey dewatering was investigated in laboratory scale experiments in which FO and RO were utilized for whey concentration and water recovery, respectively. FO experiments were carried out at different conditions of cross-flow rate, temperature, membrane kind, membrane orientation mode, and microfiltration (MF) pretreatment. A single-step RO system was applied for water recovery from the FO draw solution. In the FO process, about 1.6 L water of 3 L whey was withdrawn into 3M NaCl draw solution during 6 h operating time, and a sufficiently high performance in whey concentration was obtained, with the solid content being increased from 6.8 to 14.3%. However, the process resulted in a high salt permeation into the whey, in addition to some soluble organics being permeated into the draw. RO process are operated with relatively low performances due to excessive salt concentration of the FO draw solutions, which indicates that there is a need for RO implementation in two or three sequential levels for achieving an absolute success in the water recovery from whey. Despite the fact that MF pretreatment to some extent decreased the FO performance, it could be used for directly productive activities intended to recover fats from whey. Results have proved that prior to whey powder production, the integrated system could be effectively employed for whey concentrations up to a solid content of 25–35%. Accordingly, FO–RO system can be utilized as a novel alternative in concentrating whey compared to ultrafiltration-RO combined system widely used worldwide. However, before practical implementation of the system, an optimization between alleviating the salt concentration in FO draw and multi-step RO implementation should have to be considered concurrently with the economics of the investment.

A comparative life cycle assessment of hybrid osmotic dilution desalination and established seawater desalination and wastewater reclamation processes

The purpose of this study was to determine the comparative environmental impacts of coupled seawater desalination and water reclamation using a novel hybrid system that consist of an osmotically driven membrane process and established membrane desalination technologies. A comparative life cycle assessment methodology was used to differentiate between a novel hybrid process consisting of forward osmosis (FO) operated in osmotic dilution (ODN) mode and seawater reverse osmosis (SWRO), and two other processes: a stand alone conventional SWRO desalination system, and a combined SWRO and dual barrier impaired water purification system consisting of nanofiltration followed by reverse osmosis. Each process was evaluated using ten baseline impact categories. It was demonstrated that from a life cycle perspective two hurdles exist to further development of the ODN-SWRO process: module design of FO membranes and cleaning intensity of the FO membranes. System optimization analysis revealed that doubling FO membrane packing density, tripling FO membrane permeability, and optimizing system operation, all of which are technically feasible at the time of this publication, could reduce the environmental impact of the hybrid ODN-SWRO process compared to SWRO by more than 25%; yet, novel hybrid nanofiltration-RO treatment of seawater and wastewater can achieve almost similar levels of environmental impact.

Socio-economic & technical assessment of photovoltaic powered membrane desalination processes for India

Fresh water crisis is evident in many parts of India, varying in scale and intensity at different times of the year. About seven states are underlain by brackish ground water affecting 42 million people. 25% population of India resides along the coast having easy access to seawater. Hence, these saline water resources can be exploited to meet their water requirements. Desalination technologies create new sources of fresh water from seawater or brackish water, but they do require energy. This paper addresses the socio-economic and technical feasibility of powering membrane desalination technologies with photovoltaic (PV) systems in regions which have mixed advantage of high solar potential and disadvantage of presence of saline water. A database of Indian population dependence on saline water, its regional solar potential and present state of desalination have been compiled. Technical aspects of reverse osmosis (RO) and electrodialysis (ED) membrane desalination processes powered by PV are addressed and desalinated water cost, obtained through PV-RO and PV-ED processes, are compared with diesel powered RO and ED processes respectively for a plant capacity of 50 m 3/day over a 20 year working life of the plant. The technology will augment fresh water requirements of India and contribute to its sustainable development.