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Technologies for wastewater reclamation and water reuse within oil refineries have been gaining particular attention over the past decade due to legislative pressures associated with the efficient use of water resources and wastewater discharge. Having to constantly rely on access to great amounts of water, the oil and gas industry has been seeking opportunities to reclaim water using sustainable and efficient management procedures. In the present study, an on-site pilot plant treatment study on real refinery stripped sour water using reverse osmosis was conducted with the goal of removing the main pollutant blocking the possibility for water reuse in the refinery cooling tower, phenols. A technical and energy evaluation was performed where 90% of the initial wastewater was recovered without loss of permeate quality with 98% rejection of phenols. The installation of an energy recovery device with the reverse osmosis plant could drop the energy input demand to 1.2 kW h m−3, allowing the operating costs to decrease from 1.37 € per m3 to 0.41 € per m3. Treatment on an industrial scale would allow the refinery to save up to about 375 000 m3 per year in water and up to approximately 417 000 m3 per year in wastewater volume discharged, translating into net savings of up to 286 000 € per year and a payback period of down to 4 years. The current treatment proposed showed low carbon footprint and negligible waste generation, based on green metric tools; however careful consideration should be taken in the management and treatment of the concentrate stream.

Due to the continuously increasing demand for fresh water in the desert and remote areas, the development of non-conventional water resources in Egypt is essential. The most advanced and promising desalination system is the reverse osmosis (RO) system. In this paper, a 5000 m3/day RO desalination plant in the city of Nuweiba in Sinai, Egypt is taken as a case study. The measured data of the plant are recorded during 5 years of its normal operation. Also, experimental tests are carried out on site to investigate the influence of the main design and -operating parameters on the plant performance. The RO system is found to be sensitive to the variation in the feed water temperature, pressure and salinity. The used maintenance schedule is also seen to be suitable for the plant, since the change in plant performance during the operation period is not noticeable. On the other hand, a cost analysis is carried out on the RO plant components. The major factors affecting the cost of product water of this plant are the power consumption and capital cost. Surprisingly, the chemical treatment cost is one of the lowest in percentage. In this case, the power consumption cost is 35.1% and the capital cost is 33.6% and that of maintenance and repairs represent only 4.9% while the chemical treatment represents 10.6% of the total cost.

Often industrial variables can be difficult to measure due to such factors as extreme conditions or complex compositions. In such cases, soft sensors have been developed that use available system information and measurements to estimate these difficult-to-obtain variables. In practice, the measurements that are to be estimated by a soft sensor are often infrequently measured or delayed. Occasionally, these sampling times or delays are time varying. At present, most research has considered these parameters to be time invariant, and thus, there is a need to consider the time-varying case. Therefore, this paper will evaluate the impact of time-varying delays and sampling times for the design of a data-driven soft sensor. Modifications will be proposed that will increase the robustness and performance of the soft sensor. The reliability of the estimate will be shown using the Bauer–Premaratne–Duran Theorem. Furthermore, the proposed soft sensor system will be tested using simulations of a continuous stirred tank reactor (CSTR) and an reverse osmosis plant. Simulation showed that the modified soft sensor gives good estimates, whereas the traditional soft sensor gives an unstable estimate for the CSTR and reverse osmosis plant.

In this work, a salp swarm optimization (SSO)-based controller design is proposed for photovoltaic reverse osmosis (RO) desalination unit. The photovoltaic RO model considered in this work is basic...

Chronic Kidney Disease with unknown etiology (CKDu) is one of the crucial health issues in North Central, Uva, North Western, North, Central, and Eastern Provinces of Sri Lanka and incapacitates the kidney function. The main source for the CKDu has not yet been identified, though many scientists believed that the number of certain drinking water quality parameters is changed due to the contamination of water sources by agricultural activities. Hence, the government of Sri Lanka introduces electrically driven Brackish Water Reverse Osmosis (BWRO) plants with a capacity of 10 tones/day to supply safe drinking water for the impacted community though it is an energy-intensive process. Concurrently, a smaller version of an electrically driven BWRO plant was introduced to the rural farming community for their domestic use. However, it was not practically worked out due to various reasons such as high cost, unavailability of electrical power supply for those villages. In this study, an economical air operated domestic use BWRO plant with zero-emission was designed. This anticipated system significantly reduces the government expenditures to subsidize the water purification cost by 50% of the existing expenses. Besides, simple payback time was found to be 2.5 years, and the benefit-cost ratio to be more than 1. Evaluating the performance with the conventional values, it comprehends with more sustainable and economically viable system compared to the existing method of water purification.

Desalination process is an essential demand to overcome the lack of drinking water in remote areas in Egypt. Hybrid energy system drives desalination techniques to provide potable water for islands and coastal zones where there is no electrical grid. This paper analyzes the technical configuration, sizing and economic optimization of off-grid hybrid energy system powered reverse osmosis plant. The hybrid system consists of wind turbines, photovoltaic panels, converters, storage batteries, and a diesel generator. The objective of this study is to satisfy the electrical energy demand of the reverse osmosis (RO) plant with a freshwater capacity of 100 m3/day for use at Nakhl, North Sinai, Egypt. This simulation studied eleven different configurations of energy sources to select the optimal case at the proposed location. Homer package is used to select the cost-effective, sustainable and socially accepted system. The simulation is based on calculating the net present cost (NPC), excess system electricity, cost of energy (COE) and carbon dioxide emissions (CO2). Through the study, the optimal configuration consists of 160 kW photo-voltaic (PV) panels, 19 strings of lead-acid batteries and a 50 kW diesel generator system. The optimal case achieves the lowest cost of energy ($0.107/kWh) and net present cost ($502,662).

The purpose of our study was to reduce the carbon footprint of seawater desalination plants that use reverse osmosis membranes by introducing on-site renewable energy sources. By using new-generation membranes with a low energy consumption and considering wind and photovoltaic energy sources, it is possible to greatly reduce the carbon footprint of reverse osmosis plants. The objective of this study was to add a renewable energy supply to a desalination plant that uses reverse osmosis technology. During the development of this research study, photovoltaic energy was discarded as a possible source of renewable energy due to the wind conditions in the area in which the reverse osmosis plant was located, hence, the installation of a wind turbine was considered to be the best option. As it was a large-capacity reverse osmosis plant, we decided to divide the entire desalination process into several stages for explanation purposes. The desalination process of the facility consists of several phases: First, the seawater capture process was performed by the intake tower. This water was then transported and stored, before going through a physical and chemical pre-treatment process, whereby the highest possible percentage of impurities and organic material was eliminated in order to prevent the plugging of the reverse osmosis modules. After carrying out the appraisals and calculating the amount of energy that the plant consumed, we determined that 15% of the plant’s energy supply should be renewable, corresponding to 1194 MWh/year. As there was already a wind power installation in the area, we decided to use one of the wind turbines that had already been installed—specifically, an Ecotecnia turbine (20–150) that produced an energy of 1920 MWh /year. This meant that only a single wind turbine was required for this project.

As a result of climate change, population increase and improvement of living standards, the water demand is annually growing drawing worldwide attention on seawater desalination to face water crisis. The total global desalination capacity is dominated by Reverse Osmosis (RO) and, often, this desalination process is fed with the brackish water extracted from coastal aquifers. After this process the desalted freshwater is obtained at a recovery factor of ca. 50%, while concentrate byproduct, named brine, is disposed back to coastal aquifers, seas, oceans or evaporative ponds, determining detrimental effects on the surrounding environment. A common approach to clean out the brine is the deep-well injection into coastal aquifers, exacerbating the seawater intrusion. The ultimate result is a reduction of the available water both in terms quantity and quality hampering the benefits of the desalination. The aim of this study is to investigate the effects of brine water injection in the Nile coastal aquifer, one of the largest underground freshwater reservoirs in the world, and to find a way to minimize and manage the environmental impact of the RO process. In order to simulate the effects of the brackish water extraction and the brine deep-injection on the Nile coastal aquifer, a combined seawater intrusion, numerical models for flow and salt transport model in aquifers and the solution-diffusion in RO practices were implemented. Different management scenarios were considered and their consequences on salt mass storage in the Nile coastal aquifer evaluated. According to the numerical results, the salinization of the coastal aquifer can be mitigated by reducing the concentration of the water feeding the reverse osmosis plant, i.e., mixing the extracted brackish water with a lower salinity water. Besides, low feed salinity leads to significant gains by decreasing the specific energy consumption of the desalination process.

One possible contender to replace conventional reverse osmosis schemes is an energy solution where inexhaustible resources work together with a reverse osmosis plant. Based on the experience of an existing wind-powered desalination scheme run for more than 15 years by Soslaires Canarias S.L., the final objective of this paper is to propose improvements to the scheme so as to achieve a reduction in the cost of water (through restrained capital expenses) for the sake of greater feasibility and efficiency. The cost of the scheme is evaluated assuming a combined use of a reverse osmosis desalination plant and wind energy, using, for this purpose, the (exclusive) information provided by the industrial partner. Results showed that by carrying out the actions suggested in this paper, this scheme would be able to reduce its cost of water (COW) by about 0.022 EUR per cubic meter for the current LCOE of wind turbine technology in the study area (about 6 c€/kWh for the southeast of the island of Gran Canaria, Spain). This would mean that with an additional total capital investment cost of 196 000 € (from the current scheme of Soslaires Canarias S.L.), and supposing an average membrane life expectancy of 10 years for the current state-of-the-art membranes, a net present value of 74 360.95 €, a profitability index of 1.3794, and a 224.4881% internal rate of return would be achieved.

Fouling in membrane filtration processes is problematic. Causes are often specific depending on feed water constituents, the membrane and the chemical products used. Some fouling will badly affect membrane performance and cleaning will therefore be necessary. Cleaning can be supported by antiscalant treatments to reduce the risk of membrane fouling. However, some antiscalants may also lead to fouling. This paper presents the major problems of reverse osmosis plant in Jerba Island, namely the influence of antiscalant type on the water characteristics and membrane fouling. This was related to the increase of pressure drop, permeate conductivity and cleaning frequency. To identify the causes of membrane fouling, different investigations were carried out. Membrane autopsy, chemical analysis of feed water, follow-up of the operation parameters. The objective of membrane autopsy, by means of SEM/EDS, was to carry out a destructive analysis on a fouled membrane in order to identify the major causes of fouling. The results show that the film was composed mostly of organic matter, with significant presence of nitrogen, iron and silicates. These findings demonstrate how the antiscalants altered the water characteristics. Thus, the selection of the type of antiscalant should take into account the associated contribution to membrane fouling development.

Performance of reverse osmosis plant is evaluated and calculated on different operational parameters by putting them under keen observation and derived that how productivity of the plant is maintained to get better results. Treatment techniques are explicitly discussed, implemented and suggested accordingly in these steps. Graphical representation depicts the changing behavior of parameters and ultimately productivity. Utilization of the rejected water is applied and advised according to one’s feasibility. Analyzed the whole process for the economic evaluation especially concentrating on the reject water stream with various tactics and methods to get the maximum outcome in the recovery of water.

Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG [Abstract] Drinking water provision has been a constant challenge in the Sahrawi refugee camps, located in the desert near Tindouf (Algeria). The drinking water supply system is itself divided in three zones which pump groundwater from different deep aquifers. It is equipped with reverse osmosis plants and chlorination systems for treating water. The allocation of water supplied to the Saharawi refugees for human consumption in 2016 has been estimated at between 14 and 17 L/person/day on average. This supplied water volume is below recommended standards, and also below the strategic objective of the Sahrawi government (20 L/person/day). Yet the local groundwater resources are huge in comparison with estimated consumption, and hence there is great potential for increasing the supplied volume through effecting improvements in the supply system. The physico-chemical quality of the raw and supplied water between 2006 and 2016 has been assessed according to Algerian standards for human consumption. The raw water of two zones of the supply system presents a very high conductivity and high concentrations of chloride, nitrate, fluoride, sulfate, sodium, calcium, potassium and iodide concentrations of natural origin, which may entail health risks. The treatment of water in a reverse osmosis plant greatly improves its quality and osmosed water met the standards. However, the supply of osmosed and raw water needs to be combined in Zone 1, to avoid an excessive reduction in water volume, and the supplied raw water poses a risk to the health of the refugees. The present study provides an example of a drinking water supply system under extreme drought conditions and in the political and social conditions of a refugee camp. Furthermore, it establishes a reference for supplied water allocation and quality in the Sahrawi refugee camps.

The work deals with renewable energy project, in the context of the deregulated energy market. Special attention is focused on renewables and on the situation in Italy from the standards point of view. The set up of a wind farm and a PV plant in coastal Sardinian area for both electricity and desalinated water production is studied. The convenience of fuelling desalination plants through renewables is investigated by taking into account additional on-side trading instruments. A model to simulate the operation wind and PV systems is applied both to calculate the produced energy and to assess the performance of a desalination plant, namely a reverse osmosis plant driven with PV and wind sources that works in a small island site.

The following study aims to analyze and to optimize the technical performances of a desalination plant, based in khenifra city in the central region of Morocco. Reverse osmosis system is used as a desalination process in order to treat the water of the river Oum ErRiaa. The river water quality is variable depending on the season, and its chloride content does not exceed the value of 866 mg/l, which represents the design reference of the reverse osmosis plant. Faced with the decrease of the salinity of this water, the operator was forced to reduce to the third, the operation of this plant, which is composed of three reverse osmosis units functioning every two days alternatively. Moreover, the monitoring of the technical indicators of the plant, revealed the absence of membranes fouling. This is due to frequent membranes rinsing during the units stops. As a result, the plant performances as defined during the design cannot be verified. It was then important to identify other approaches to analyze the performances of this station. The questioning of desalination plant design, led us to make simulations with two different softwares, on a new basis, which is the current quality of the river water, characterized by a conductivity value of only 1230 μs/cm instead of 3013 μS/cm, which was the one taken to design the plant. The results obtained indicated the possibility of reaching a better conversion rate of around 88% for low mineralized waters compared to 78% for the quality of water taken into account for the desalination plant design.

The unpeeled bunches of lychee fruits were purchased from local market of Navsari, Gujarat, India and were divided into two lots; one was treated with ozonized reverse osmosis plant water and another was using non-ozonized reverse osmosis plant water. The washed samples were stored at cool place in ambient condition. The total plate count of these lychee fruits was recorded before and after washing treatment. The organoleptic evaluations of these treated samples were carried out using 9-point hedonic scale. The results indicated that the initial microbial load of lychee were recorded from 3580 cfu g(-1) to 10 cfu g(-1) and 560 cfu g(-1) for ozonized and non-ozonized reverse osmosis plant water washing treatment, respectively. However, the microbial load again increased and recorded above 3000 cfu g(-1) after 6 and 4 days of storage of lychee for ozonized and non-ozonized reverse osmosis plant water washing treatment, respectively. The overall acceptability score also reduced with respect to storage period. It was reduced from 8.3 for fresh lychee on the first day to less than 5 after 6 and 4 days of storage for ozonized and non-ozonized water washing treatment, respectively. Therefore, from this experiment, it can be concluded that ozonized water washing treatment can extend the storage life of lychee fruit by a week by reducing the microbial load; however it cannot eliminate the microbial load completely.

Automation and reliability are the crucial elements of any advance reverse osmosis plant to meet the environmental and economic demands. Early fault indication, diagnosis and regular maintenance are the key challenges with most of the reverse osmosis plants in the Indian scenario. The present work introduces a modern reverse osmosis (RO) plant status monitoring unit to monitor different plant parameters in real time and early prediction for faults and maintenance. Developed RO plant status monitoring unit consists of a touch screen-based embedded monitoring unit, water quality sensors (pH, TDS), sampling chamber for controlled water flow, flow sensors, pressure and level sensors. The present system has been developed in a modular fashion so that it could be integrated with any capacity of RO plant units. Developed embedded system monitors various parameters of the plant such as input power, efficiency of the plant, level of input and output water tank and also guides operator with instructions for plant operation. Other than this, a dedicated smartphone app interface has been developed for the operator to acquire data from status monitoring unit, storage on smartphone, and transfer it to the cloud. The developed smartphone-based app also provides facility to integrate plant data with Google map with location information for easy understanding and quick action. The system has also a backup facility to transfer data to the server using 2G GSM module during the unavailability of the operator. A dedicated centralized Web server has been developed for real-time visualization of all installed RO plant status monitoring units. Different machine learning techniques have been implemented on acquired sensors data to predict early warnings related to power failure, membrane fouling and scaling, input water shortage, pipe, tank leakage, water quality sensors damage, non-operation or wrong operation of the plant along with different maintenance actions such as membrane water and chemical wash. Developed RO status monitoring unit has been tested with various RO plants having capacity from 500 LPH to 2000 LPH and deployed at various nearby villages of Rajasthan.

Hybrid PV/Thermal (PV/T) systems can generate both electrical and thermal energy simultaneously. These systems are already finding interesting applications in the fields of desalination, sensible heating/cooling and other allied industrial processes. An effective way to further improve the overall system efficiency is by using V-Trough’s to concentrate incoming sunlight and enhance the power output from these systems. In this work, we study the performance of a V-Trough PV/T system connected to a reverse osmosis plant in India. A coupled optical, electrical, and thermal model is presented and validated by experiments. The optical analysis was carried out while including the variations in suns altitude and zenith angle over the day. The impact of the variable inlet water temperature with time is included in the model. The performance of a V-Trough PV/T system is compared with a standard PV system. An average increase of 35% was observed in the electrical power output from the V-Trough PV/T system as compared to the conventional one, with the maximum being 63%. Using the water circulation, an average of 778 BTU/m2 of thermal energy was extracted from the V-Trough PV/T system. A maximum temperature difference of 5.2 °C was observed in the feed water at the system outlet, this accounted for a maximum 1/3rd of the total energy recovery when using the V-Trough PV/T system. Feeding heated water to the RO unit in the PV-RO system helped in significantly increasing the quantity and quality of the permeate obtained from the system. A parametric study of the effect of varying mass flow rate on the performance of the system is also discussed.

Membrane filtration systems are successful methods to make high-quality water. An important issue and most challenging problem regarding these systems is fouling which arises from particle deposition in and on the membrane surface. Membrane fouling reduces performance of membranes and increases operational costs. Due to this problem, a reliable index to predict the fouling potential of feed water is important in preventing and characterizing membrane fouling and for monitoring the performance of pre-treatment during plant operation. The conventional fouling indices such, as SDI and MFI, are usually determined via off-line measurement techniques based on dead-end filtration, which does not consider the actual flow conditions. To have a better understanding of the conventional fouling indices, the effect of several parameters on SDI, MFI, MFI-UF (constant pressure and constant flux) were investigated. In contrast with MFI, the SDI results confirmed the non-linear response to foulants concentration. The specific cake resistance for colloidal silica and humic acid was found to be maximum at low concentrations and gradually declined at higher concentrations. It was also highlighted that fouling by mixed foulants cannot be related simply to the individual MFIs. The effect of salt concentration on MFI-UF (constant pressure and constant flux) was also investigated over a broad range of NaCl (0 to 25,000 mg/L) for colloidal silica and humic acid. The results indicated that MFI-UFconst.pressure of the colloidal silica passed through a maximum (under constant pressure filtration) while for humic acid MFI-UFconst.pressure increased monotonically. To overcome the limitations of these techniques, an on-line flow simulator, the feed fouling monitor (FFM), has been developed for characterization of the fouling propensity of feed water to RO. The FFM is based on the principle of particle deposition and cake layer formation on a small ‘collection’ membrane in the device under cross flow conditions, which can be correlated to the particulate fouling (including colloidal particles and macromolecules) encountered in a RO operation. The information obtained from FFM was used to estimate cake resistance in RO in order to predict RO fouling profiles at the same hydrodynamic conditions. However, the predicted RO profiles were found to underestimate the actual RO performance due to ignoring the contribution of the cake-enhanced osmotic pressure (CEOP) effect. The model was extended to include the contribution of CEOP and ultrasonic time domain reflectometry (UTDR) was used to monitor the rate of cake thickness increase in RO in order to estimate the cake-enhanced osmotic pressure (CEOP). The cake resistance (obtained from FFM) combined with CEOP could more accurately predict the RO fouling profiles using colloidal silica as a foulant model. A salt tracer response technique (STRT) was also used to measure directly concentration polarization trends and estimate the contribution of CEOP under constant flux using both organic and inorganic foulant models. The predicted RO fouling profiles obtained from combination of FFM and STRT provided a good estimation of the transmembrane pressure (TMP) rise during RO fouling for both humic acid and colloidal silica. The contribution of CEOP to TMP rise was typically greater than the cake resistance. Doctor of Philosophy (CEE)

The focus of this thesis work was on the fundamentals of colloidal and biofouling in reverse osmosis (RO) desalination and reclamation. A novel sodium chloride tracer response technique coupled with ultrasonic technique was employed to monitor the progress of fouling by silica colloids, alginic acid and Pseudomonas fluorescens. This study provided an insight into the interplay between critical flux, concentration polarization or CP (through the enhanced osmotic pressure effect) and fouling. In colloidal fouling, critical flux determined the deposition of particles on the membrane surface. The build up of deposit layer caused an additional hydraulic resistance as well as the cake enhanced osmotic pressure (CEOP) effect, which could be the predominant contributor in the membrane performance loss. Whereas in biofouling, it was postulated that the role of CP was to control the level of nutrient for the growth of biofilm, which in turn caused the biofilm enhanced osmotic pressure (BEOP) phenomenon. Doctor of Philosophy (CEE)

In this paper we investigate the potential for using suspension crystallisation for the production of clean drinking water from a seawater source. The experimental results show that the produced water from the suspension crystallisation plant not only meets water quality standards but is comparable in ionic composition to premier bottled water from around the globe. The experimental results obtained from a pilot scale suspension crystallisation unit showed that the achievable water recovery was around 41% and the salt rejection ratio reached over 99%, which is comparable with most desalination technologies. Moreover, a hybrid RO-Freeze plant has been proposed that is capable of significantly increasing the potable product water that could be achieved by RO alone (~ 400% increase), while simultaneously concentrating the RO brine (used as feed water) producing a super brine of ~ 13 wt%. While there is a cost to this additional process in terms of capital and energy that must be quantified, the obvious increase in water harvest and reduction in residual brine quantity lead to a very attractive desalination process. If the energy demands are acceptable, then this technology could lead to a more sustainable water future.

Reverse osmosis (RO) has successfully emerged as a broadly-used commercial water purification technology in recent decades. Nevertheless, RO membrane elements, the core component of this purification process, are frequently subjected to premature degradation and performance deterioration, adversely impacting RO plant operation & maintenance. Membrane autopsy is a well-proven yet under-valued procedure for effectively assessing the condition of membranes and determining the root-cause of performance loss. This paper aims to provide a general methodology utilized commercially to perform membrane autopsy and employ three case studies to explicitly demonstrate the value addition to operators and end-users when applying membrane autopsy in (1) failure analysis and trouble-shooting, (2) operation optimization and routine monitoring, and (3) asset management and maintenance enhancement.

The decarbonisation of membrane desalination is a grand challenge due to the competing demands of more water for a thirsty world and the urgent need to reduce carbon emissions to mitigate climate change. This paper is a review of some developing strategies that could lead to lower energy use and thereby reduce the carbon foot print of desalination. Each strategy brings benefits along with technical challenges that are research opportunities. The use of very low energy ‘engineered biofilms’ coupled with biomimicry control of biofouling could almost eliminate pretreatment energy. Improved membranes based on ‘water channels’ could contribute to reduced energy demand but high flux operation will need novel mass transfer control and will be constrained by module engineering. Significant energy benefits could come from combining seawater RO with wastewater reclamation using forward osmosis and pressure-retarded osmosis (PRO), although fouling by the wastewater stream requires special attention. The overall potential of the novel pretreatments, membranes and post-treatments is to more than halve the net energy of RO desalination. However there would be significant trade-offs to achieve this level of decarbonisation. The application of renewable energy is considered in the context of a membrane-enabled osmotic battery using PRO for discharge and advanced RO for recharge. Finally, low energy desalination for agriculture is being developed using novel applications of forward osmosis.

Reverse osmosis (RO) is a newly applied feasible technology of fresh water source in the coastal areas of Bangladesh. The research has been undertaken to know the present water security related resilience status at Patharghata upazila of Barguna district in Bangladesh. The study also focuses to strengthen resilience in water security for the coastal households by using reverse osmosis technology. The people of the study area face safe drinking water shortages problem all year round but during dry season the problem becomes more acute. The study was conducted using questionnaire survey method, focus group discussion (FGD), water sample collection and testing to find out the water security status of the study area. During questionnaire survey, mainly the head of the households were interviewed. Drinking water samples were collected from the randomly selected households of the study area for laboratory testing. The present status of drinking water sources, respondent’s perception of drinking water facilities, distance of water sources, general information of the pond, water collection system, water samples test result and health risk problems were assessed to measure the water security status of the area. From the survey and test results, it reveals that the people of the area facing severe fresh drinking water crisis. It is found that about 62% households of the study area are in water insecurity problem. A generalized feasibility test of a reverse osmosis plant was done which indicates that the reverse osmosis system is more technical and economically feasible drinking water source among other technologies of the study area. The system can also play a great role as a disaster risk reduction (DRR) based solution of drinking water shortages for building water security related resilience at coastal household level in Bangladesh.

This paper reports on a feasibility study into the integration of a multi-effect distillation plant with a central receiver plant to generate electricity for the Namibian grid, and fresh water for the community and mining operations at Arandis. Arandis receives on average 2528 kWh/m2/year of solar irradiation, is only 48 km from the coast and 580 m above sea level, making it attractive for a cogeneration plant. Desalination is energy intensive, but the required energy is freely available from the waste heat rejected at the condenser of a Rankine cycle. In this study, high level thermodynamic models of a multi-effect distillation and central receiver plant were developed to better understand the economics of such a cogeneration plant. Results indicate that a 100 MWe central receiver plant combined with a multi-effect distillation plant, is capable of servicing the current water demand in the region. Despite the high capital costs of central receiver plant, as well as pumping seawater inland, the plant is economically viable within the proposed tariff structure for renewable energy in Namibia, and existing water tariffs. Profit parity between a cogeneration plant and a stand-alone, dry-cooled central receiver plant is reached for top brine temperatures above 65 °C. Under these conditions, water sales would subsidize electricity production. However, it is not price competitive with a grid-powered reverse osmosis plant on the coast. The most significant barriers in making cogeneration plant competitive against more conventional desalination methods such as reverse osmosis are the high capital cost of the cogeneration plant, and pumping seawater inland.

The present study was undertaken as the first plant scale application and evaluation of Best Available Techniques (BAT) within the context of the Integrated Pollution Prevention and Control/Industrial Emissions Directive to a textile mill in Turkey. A "best practice example" was developed for the textile sector; and within this context, BAT requirements for one of the World's leading denim manufacturing textile mills were determined. In order to achieve a sustainable wastewater management; firstly, a detailed wastewater characterization study was conducted and the possible candidate wastewaters to be reused within the mill were identified. A wastewater management strategy was adopted to investigate the possible reuse opportunities for the dyeing and finishing process wastewaters along with the composite mill effluent. In line with this strategy, production processes were analysed in depth in accordance with the BAT Reference Document not only to treat the generated wastewaters for their possible reuse, but also to reduce the amount of water consumed and wastewater generated. As a result, several applicable BAT options and strategies were determined such as reuse of dyeing wastewaters after treatment, recovery of caustic from alkaline finishing wastewaters, reuse of biologically treated composite mill effluent after membrane processes, minimization of wash water consumption in the water softening plant, reuse of concentrate stream from reverse osmosis plant, reducing water consumption by adoption of counter-current washing in the dyeing and finishing processes. The adoption of the selected in-process BAT options for the minimization of water use provided a 30% reduction in the total specific water consumption of the mill. The treatability studies adopted for both segregated and composite wastewaters indicated that nanofiltration is satisfactory in meeting the reuse criteria for all the wastewater streams considered. (C) 2017 Elsevier Ltd. All rights reserved.

The industrial processes require large quantities of water. The presence of discharges results not only in significant environmental impact but implies wastage of water resources. This problem could be solved treating and reusing the produced wastewaters and applying the new zero liquid discharge approach. This paper discusses the design and the performances of reverse osmosis membranes for the upgrading of full scale platform for industrial liquid wastes. The final effluent from the ultrafiltration unit of the full scale plant was monitored to design the reverse osmosis unit. Previous modelling phase was used to evaluate the specific ordinary and maintenance costs and the final effluent quality (2.7 €/m3). The system was designed in triple stages at different operative pressures. The economic feasibility and the payback period of the technology at different percentages of produced permeate were determined. The recovery of 90% was identified as profitable for the reverse osmosis application. One experimental pilot plant applying the reverse osmosis was used to test the final effluent. Moreover, the same flow was treated with second pilot system based on the forward osmosis process. The final efficiencies were compared. Removals higher than 95% using the reverse system were obtained for the main macropollutants and ions. No sustainable applicability of the forward osmosis was determined.

Hot climate countries require large amounts of desalinated water. The Reverse osmosis (RO) technique is currently considered the most reliable technique for brackish water and seawater desalination. However, its power consumption is considerably higher than all other techniques. Therefore, the present study investigates the performance of reverse osmosis plants in hot climate conditions. A typical Reverse osmosis system was designed, constructed and investigated. The ROSA software was also used for the analysis of seven different membrane elements. The experimental data were utilized in order to validate the simulation results of the ROSA software. A variance-based sensitivity analysis was performed in order to define the most effective design and operating parameters. The present investigation shows that the tap and brackish water membrane elements are more sensitive to the feed water temperature rather than the feed water pressure and concentration. Meanwhile, seawater membrane elements are more affected by the feed concentration. The detailed investigation of the different membrane elements shows that wastewater reclamation using reverse osmosis technology could be a significant source of low-cost fresh water for hot climate countries.

In this study, a newly devised seawater desalination process, namely, the draw solution assisted reverse osmosis (DSARO) process, is proposed. A mathematical model for the DSARO process was developed and energy consumption and economic evaluation models were constructed to assess the feasibility of the DSARO process compared to the conventional reverse osmosis (RO) process. This work presents a characterization of important variables and the research on the effects of these variables. Compared to the conventional RO process, the DSARO process could have a 10% lower specific water production cost. The operating pressures required to reach 40% of overall recovery were approximately 35 bar in the 1st RO process, and 30 bar in the 2nd RO process. Due to its operating pressure being lower than the conventional RO process, the capital and membrane replacement costs could be reduced. The required conditions in the 1st RO membrane to drive the DSARO process were that the membrane structure parameter must be lower than 0.13 mm, and the maximum operating pressure should be higher than 35 bar. Even though these conditions are not available commercially at present, they could be attained based on the best available membrane technology in the literature.

A pilot-scale reverse osmosis (RO) followed behind a membrane bioreactor (MBR) was developed for the desalination to reuse wastewater in a PVC production site. The solution-diffusion-film model (SDFM) based on the solution-diffusion model (SDM) and the film theory was proposed to describe rejections of electrolyte mixtures in the MBR effluent which consists of dominant ions (Na+ and Cl-) and several trace ions (Ca2+, Mg2+, K+ and SO42-). The universal global optimisation method was used to estimate the ion permeability coefficients (B) and mass transfer coefficients (K) in SDFM. Then, the membrane performance was evaluated based on the estimated parameters which demonstrated that the theoretical simulations were in line with the experimental results for the dominant ions. Moreover, an energy analysis model with the consideration of limitation imposed by the thermodynamic restriction was proposed to analyse the specific energy consumption of the pilot-scale RO system in various scenarios.

The osmotically driven membrane process, such as pressure-retarded osmosis (PRO) or forward osmosis (FO), assisted reverse osmosis (RO) hybrid systems are investigated for low-energy cost seawater desalination and wastewater treatment, and the simultaneous RO brine (or RO concentrates) management. Unlike the earlier studies, the hollow fiber types of modules are used in these hybrid systems. For commercialization of the hybrid systems, a big concern is that how much energy per unit product (i.e., specific energy) can be saved due to the hybrid systems as compared to the most preferred conventional RO technique. For this, the generalized mathematical models for an axial-flow and a radial-flow hollow fiber module are developed in the current study. These models are applicable to evaluate all PRO, FO, and RO processes. For an RO recovery of 50% and FO/PRO dilution of 40%, it is found that around 25% specific energy saving may be realized in both the hybrid systems as compared to the conventional RO system at studied operating conditions. Interestingly, the results also reveal that as the RO recovery increases, the specific energy saving increases for the FO-RO hybrid system but decreases for the RO-PRO hybrid system.

Seawater reverse osmosis (SWRO) desalination technology accounted for 78% of annual new contracted desalination capacity from 2006 to 2012, due of its lower electrical power consumption (3–5 kWh/m3) versus thermal desalination technologies (up to 18 kWh/m3), such as multistage flash and multiple effects. However, the existing SWRO desalination process still needs further improvement to lower the energy consumption. Recently, a novel hybrid SWRO desalination system using pressure-retarded osmosis (PRO) technology has been studied, which can recover a large amount of osmotic power from the concentrated brine. In this study, GS Engineering & Construction Corp. (GS E&C) developed an advanced SWRO-PRO process to economically couple this PRO technology with a conventional SWRO desalination process. To investigate the SWRO-PRO process, pilot and demonstration plants, of 20 m3/d and 240 m3/d PRO treatment capacity, were constructed and thin-film composite spiral-wound PRO membrane modules (8 inches) were assessed. The operating parameters of the pilot plants, such as pressure, temperature, and flow rates of the draw solution and the feed solution, were found to be important factors determining the plant energy consumption and operating efficiency. An economic analysis of a large-scale SWRO-PRO hybrid desalination is also described.

The strengthening of requirements for the protection of surface-water sources and increases in the cost of reagents lead to the necessity of using membrane (especially, reverse osmosis) technologies of water desalination as an alternative to ion-exchange technologies. The peculiarities of using reverse osmosis technologies in the desalination of waters with an increased salinity have been discussed. An analogy has been made between the dependence of the adsorptive capacity of ion-exchange resins on the reagent consumption during ion exchange and the dependence of the specific ion flux on the voltage in the electrodialysis and productivity of membrane elements on the excess of the pressure of source water over the osmotic pressure in reverse osmosis. It has been proposed to regulate the number of water desalination steps in reverse osmosis plants, which makes it possible to flexibly change the productivity of equipment and the level of desalinization, depending on the requirements for the technological process. It is shown that the selectivity of reverse osmotic membranes with respect to bivalent ions (calcium, magnesium, and sulfates) is approximately four times higher than the selectivity with respect to monovalent ions (sodium and chlorine). The process of desalination in reverse osmosis plants depends on operation factors, such as the salt content and ion composition of source water, the salt content of the concentrate, and the temperatures of solution and operating pressure, and the design features of devices, such as the length of the motion of the desalination water flux, the distance between membranes, and types of membranes and turbulators (spacers). To assess the influence of separate parameters on the process of reverse osmosis desalination of water solutions, we derived criteria equations by compiling problem solution matrices on the basis of the dimensional method, taking into account the Huntley complement. The operation of membrane elements was analyzed and the dependence of the output of desalinated water (permeate) through the membranes on the pressure of influent water for desalination and the dependence of the permeate output on the water viscosity and the dependence of the specific permeate output on the velocity and length of the motion of the desalination water flux were built. The values of the optimum pressure of source influent water for desalination in a reverse osmosis device were found. Provided the current prices for membrane elements (800 to 1200 USD) and cost of electricity (0.06–0.1 USD), the optimum pressure is 1.0 to 1.4 MPa.

The current status of small-scale desalination (produced water capacity 100 m3/day or less) is reviewed to provide an overview of the market segment. The use of energy-recovery devices in this market segment is also reviewed. We find that the Middle East accounts for the largest market share worldwide at present, and reverse osmosis is overwhelmingly dominant among the desalination technologies adopted. Implementation of energy-recovery devices at small scale is rare, which leads to relatively high energy consumption for small-scale seawater reverse osmosis desalination systems.

In this work, reverse osmosis water desalination plants powered by PV and solar RC cycle systems are reviewed in detail. This review focused on the display of different designs and software used to improve productivity of the desalination plants as well as the types of solar collectors used, membrane, heat transfer fluid and working fluid of the Rankine cycle. The specific energy consumption and cost of fresh water production are also of great interest in this work. According to the results presented in this review it is not recommended to use batteries with PV to drive RO desalination plants because of the high capital and replacement cost of batteries. It is also found that when the energy recovery devices are used, the pre-heating of feed water is not required, especially in the case of PV-RO systems. Currently most of working RO plants are driven by PV, whereas solar thermal power systems (usually using PTC with ORC) are still at the stage of theoretical research. Although, the PTC-ORC-RO desalination system is recommended, it has not yet been implemented on a large scale.

The possibility of using the seeded calcium carbonate precipitation technology developed previously by the author for the utilization of concentrates of existing reverse osmosis units has been explored. In modern reverse osmosis plants, scale inhibitors are used to prevent calcium carbonate scaling of membranes; the role of antiscalants consists of adsorption on the surface of forming crystals and slowing down their growth. The presence of antiscalants in the concentrate decreases the growth rate of the “seed” crystals and hampers the utilization of the concentrate. To increase the rate of crystallization, it is necessary to increase the supersaturation of the solution or increase the amount of seed crystals to be introduced. The dependence of the calcium carbonate growth rate in the antiscalant-containing concentrate on the added “seed” dose, recovery, and the pH has been studied. Various antiscalants have been compared in terms of performance, and their type most suitable for the process has been chosen. The results of comparison of the operating costs of a reverse osmosis plant involving concentrate utilization, depending on the antiscalant type used, are presented.

The main aim of this study was to conduct preliminary analysis on the performance of two conceptual designs that integrate the production of potable water, electricity, and salt. We used reverse osmosis (RO), pressure-retarded osmosis (PRO), and electrodialysis (ED) to produce potable water, electricity, and salt, respectively. The objective of the analysis is to observe how the relative positions of RO and PRO in the integrated process affect the five key parameters, i.e. the total dissolved solids (TDS) of potable water, permeate rate, the total energy requirement of the RO and ED units, net delivered power, and salt potential. We simulated each integrated design using previously validated mathematical expressions of RO, PRO, and ED. We found that the net delivered power is higher when the RO unit is located before the PRO unit. The same sequence also results in lower energy requirement for producing potable water, although the permeate rate is smaller than that of the rival sequence. On the other hand, the salt potential is not affected by the relative positions of the RO and PRO units.

Intake, pretreatment and brine disposal cost of reverse osmosis sea water desalination systems represent about 25% of total cost of the desalinated water. The present study investigates effect of reverse osmosis brine recycling employing adsorption desalination on overall system desalinated water recovery. The adsorption desalination produces dual useful effects which are high quality potable water and cooling effect. Reverse osmosis desalination is simulated by engineering equation solver (EES). The brine leaving reverse osmosis system is fed to adsorption desalination system. The adsorption desalination is driven by a low temperature heat source such as solar energy. The adsorption desalination system has been simulated by MATLAB. Results show that the proposed combination system recovery increases and permeate salinity decreases. In addition to system performance improvements, a cooling effect is generated and can be utilized for cooling applications.