Download or read book Enhancement of Operational Flexibility in Reverse Osmosis Membrane Processes by Concentrate Recycling written by Tae Lee and published by . This book was released on 2019 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: Improvements in system and process design has enabled reverse osmosis (RO) membrane technology to gain foothold in various water treatment and desalination applications. However, energy consumption and mineral scaling on membrane surfaces remain impediments to high recovery operation of RO desalination. Accordingly, research efforts have been devoted to process optimization to improve permeate water productivity, reduce energy cost, and mitigate membrane mineral scaling. In this regard, RO concentrate recycling is an effective approach for enhancing product water recovery, reducing system footprint, and lowering installation as well as operating costs of RO desalination systems and plants. Energy consumption and membrane mineral scaling propensity in RO processes are impacted primarily by the osmotic pressure magnitude and the level of supersaturation of mineral scalants at the membrane surface, respectively, which are, in turn, governed by the operational strategy. Optimization of RO processes with concentrate recycle require fundamental models of RO processes with concentrate recycle under both steady and unsteady-state operation, To date, only simple models have been proposed which are of limited applicability to practical systems given the use of various simplifying assumptions of complete energy recovery, neglect of the efficacy of concentrate flushing in unsteady-state semi-batch RO (SBRO), and omission of concentration polarization. Previous studies have not provided experimental data to corroborate conclusions regarding system performance based on oversimplifications. Moreover, SBRO operation was not assessed relative to steady state RO (SSRO) with partial recycle (SSRO-PR) which is also suitable for high recovery operation with a small footprint. Accordingly, in the present work a fundamental quantitative modeling framework was developed and implemented for the design and operation of SSRO-PR and SBRO. Modeling RO desalting, including at the limit of the thermodynamic restriction, was undertaken to evaluate the minimum energy consumption as a function of product water recovery. SBRO process analysis revealed a significant increase in the salinity range during the RO filtration period and a progressive rise in the initial filtration period salinity until the stable cycle-to-cycle operation is reached. SBRO performance is highly dependent on the efficacy of concentrate discharge and flushing during the SBRO flushing period. For the condition of concentrate flushing under ideal plug flow, energy consumption in SBRO was assessed to be lower than for single-pass RO (SPRO) operation at the same level of overall product water recovery. However, for the practical range of expected concentrate flushing efficacy energy consumption in SBRO could be significantly above that which would be attained in SPRO. Using the direct real-time membrane surface optical imaging mineral scaling was experimentally evaluated in both SBRO and SSRO-PR pilot systems, with respect to the efficacy of concentrate flushing with the undersaturated raw feed water, at given levels of supersaturation or product water recovery. The predicted RO element feed stream osmotic pressure and solution supersaturation levels (for the target mineral scalant) at the membrane surface, for a given product water recovery, were higher on average in SBRO relative to SSRO-PR as corroborated by experimental data. The experimental data revealed mineral scaling propensity, which was significantly higher in multi-cycle SBRO operation, relative to SSRO-PR at the same water recovery. However, the rates of crystal nucleation and growth were similar at when both systems are compared at the same level of average supersaturation, although the product water recovery was lower in SBRO compared to SSRO-PR. The present theoretical modeling framework, validated by experimental data, provide a fundamental approach to assessing the performance of SBRO and SSRO-PR desalting systems with respect to energy consumption and mineral scaling propensity. The presented approach provides the means necessary for optimizing these low footprint technologies for high recovery RO desalination.
Download or read book Wastewater Treatment by Reverse Osmosis Process written by Mudhar Al-Obaidi and published by CRC Press. This book was released on 2020-02-25 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wastewater Treatment by Reverse Osmosis Process provides a one-stop-shop for reverse osmosis (RO), outlining its scope and limitations for the removal of organic compounds from wastewater. This book covers the state-of-the-art on RO processes and describes ten RO process models of different features and complexities. It also covers the advanced model-based techniques for RO process operations, including various rigorous methods for process modelling, simulation, and optimization at the lowest energy cost, as well as advanced tools such as genetic algorithms for achieving the same. • Highlights different types of physico–chemical and biological wastewater treatment methods including hybrid systems • Provides an overview of membrane processes, focuses on different types of membrane processes for water treatment and explains characteristics of membrane modules • Introduces the importance and challenges of process modelling for simulation, design, and optimization and offers examples across various industries •Describes the concept of different types of genetic algorithms for process optimisation and provides the state-of-the art of the GA method in terms of its application in water desalination and wastewater treatment •Emphasizes economic aspects of RO processes for wastewater treatment With its focus on the challenges posed by an increasing demand for fresh water and the urgent need to recycle wastewater at minimum cost, this work is an invaluable resource for engineers and scientists working within the field of wastewater treatment.
Download or read book Osmotically Driven Membrane Processes written by Hongbo Du and published by BoD – Books on Demand. This book was released on 2018-03-28 with total page 283 pages. Available in PDF, EPUB and Kindle. Book excerpt: Osmotically driven membrane processes (ODMPs) including forward osmosis (FO) and pressure-retarded osmosis (PRO) have attracted increasing attention in fields such as water treatment, desalination, power generation, and life science. In contrast to pressure-driven membrane processes, e.g., reverse osmosis, which typically employs applied high pressure as driving force, ODMPs take advantages of naturally generated osmotic pressure as the sole source of driving force. In light of this, ODMPs possess many advantages over pressure-driven membrane processes. The advantages include low energy consumption, ease of equipment maintenance, low capital investment, high salt rejection, and high water flux. In the past decade, over 300 academic papers on ODMPs have been published in a variety of application fields. The number of such publications is still rapidly growing. The ODMPs' approach, fabrications, recent development and applications in wastewater treatment, power generation, seawater desalination, and gas absorption are presented in this book.
Download or read book A Continuous Process for RO Concentrate Desupersaturation written by Jack Lei and published by . This book was released on 2016 with total page 73 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reverse osmosis (RO) desalination of inland brackish water can replenish dwindling water supplies in various regions around the world. However, successful implementation of RO technology requires high product water recovery (>85%) in order to minimize the volume of generated concentrate brine. Therefore, brine management is a critical aspect of inland water desalination. At high water recovery, dissolved mineral salts (e.g. CaSO4, CaCO3) may concentrate above their solubility limits and may crystallize, potentially blocking or damaging RO membrane surfaces, reduce water permeate flux, and shorten membrane life. Therefore, it is essential to reduce the propensity for mineral scaling in order to increase the potential for high product water recovery. Attaining high recovery for inland water desalination, while avoiding membrane mineral scaling, can be achieved via an intermediate concentrate demineralization (ICD) method that utilizes two-step chemically-enhanced seeded precipitation (CESP) process. In the CESP approach, primary RO concentrate is first treated via partial lime softening in which residual antiscalant in the PRO concentrate is scavenged by precipitating calcium carbonate (CaCO3). The filtered lime treated PRO concentrate is then treated in a seeded gypsum (CaSO4[TM]2H2O) precipitation step whereby, gypsum crystal seeds promote rapid crystal growth. As a consequence, the treated PRO stream is desupersaturated with respect to gypsum and upon filtration step; a secondary RO desalting step is carried out to increase the overall product water recovery. Development of the ICD approach as a continuous process suitable for deployment in RO desalting is the focus of the present study. Accordingly, a novel system for continuous chemically enhanced seeded precipitation (CCESP) pilot was developed and constructed consisting of an alkaline chemical softening flocculation tank followed by a vertical static mixing bed reactor for seeded precipitation. The overall feasible feed slow rate for the pilot CCESP system was 0.026 - 0.25 gpm. Evaluation of the continuous ICD process performance was undertaken with a range of solutions that mimic PRO concentrate produced from desalination of San Joaquin Valley brackish water at a recovery of 63%. The major salts in the PRO concentrate feed to the CCESP included CaCl2 (30.7 mM), Na2SO4 (145.4 mM), MgSO4 (31.2 mM), NaHCO3 (11.4 mM), and NaCl (20.3 mM). Antiscalant (Flocon 260, 5 mg/L) was introduced to the PRO concentrate in order to assess the feasibility for residual antiscalant (typically present in PRO concentrate) removal so as to avoid retardation of the subsequent gypsum desupersaturation step. The CCESP system enabled continuous gypsum desupersaturation by purging spent gypsum seeds and recycling a portion of the seeds or introducing fresh seeds to the fluidized bed. Various gypsum seeds were tested, with a focus on industrial sources for gypsum (e.g. mining, drywall, food, agriculture) due to their availability and low cost. The purity of the gypsum seeds was found to be a key factor, where gypsum seeds with >98% purity were found to be most effective. Using the synthetic PRO concentrate, each of the two steps of the process were first evaluated individually to determine the optimal operating conditions and subsequently combined to evaluate the complete continuous operation. In the CCESP, lime softening occurs in a flocculation tank with recirculation, solids removal from the lime treated stream is via an inline centrifugal separator, and the gypsum seeded precipitation takes place in a fluidized bed. It was found that CCESP treatment of the PRO concentrate with 5.75 mM lime enabled up to 68% removal of the residual antiscalant. Subsequent gypsum seeded precipitation (initial seed loading of 240 g/L gypsum) reduced the PRO concentrate gypsum supersaturation index (SIg) level from 2.36 to nearly unity. The above level of gypsum desupersaturation was assessed to be sufficient for carrying out a secondary RO desalting that would enable increased recovery from 63% at the PRO step to an overall recovery of about 85% and possibly higher. The present study successfully developed a continuous ICD process and demonstrated its technical feasibility. The present results are encouraging and support the merit of evaluating the process under field conditions. Overall, it is expected that deployment of the CCESP process will enable high recovery desalting of challenging inland water of high mineral scaling propensity.
Download or read book Reverse Osmosis Process written by and published by . This book was released on 1996 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Recent Developments in Forward Osmosis Processes written by Rodrigo Valladares Linares and published by IWA Publishing. This book was released on 2017-05-15 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: Forward osmosis (FO) is an emerging membrane technology with a range of possible water treatment applications (desalination and wastewater treatment and recovery). Recent Developments in Forward Osmosis Processes provides an overview of applications, advantages, challenges, costs and current knowledge gaps. Commercial technology, hybrid FO systems for both desalination and water recovery applications have shown to have higher capital cost compared to conventional technologies. Nevertheless, due to the demonstrated lower operational costs of hybrid FO systems, the unit cost for each m3 of fresh water produced with the FO system are lower than conventional desalination/water recovery technologies (i.e. ultrafiltration/RO systems). There are key benefits of using FO hybrid systems compared to RO: • chemical storage and feed systems may be reduced for capital, operational and maintenance cost savings, • reduced process piping costs, • more flexible treatment units, • higher overall sustainability of the desalination process, while producing high quality water.
Download or read book Sustainable Membrane Technology for Water and Wastewater Treatment written by Alberto Figoli and published by Springer. This book was released on 2017-09-19 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book analyses the sustainability of membrane operations applied on an industrial scale, as well as that of those under investigation on lab/pilot scales, covering also the preparation of both polymeric and inorganic membranes. It presents reverse osmosis in desalination, membrane bioreactors for municipal wastewater treatment and pressure-driven industrial wastewater treatment in agrofood and textile fields as examples of industrial membrane operations. Regarding the membrane processes still on a lab/pilot scale, the analysis includes membrane operations for the recovery of valuable products from wastewater streams, for the removal of toxic compounds from water/wastewater, and for zero liquid discharge approaches in desalination. The book offers a useful guide for scientists and engineers working in various fields, including membrane technology, separation, desalination, and wastewater treatment. Alberto Figoli and Alessandra Criscuoli are both Senior Researchers at the Institute on Membrane Technology (ITM-CNR), Italy.
Download or read book Current Trends and Future Developments on Bio Membranes written by Angelo Basile and published by Elsevier. This book was released on 2019-09-15 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: Current Trends and Future Developments on (Bio-) Membranes: Reverse and Forward Osmosis: Principles, Applications, Advances covers the important aspects of RO, FO and their combination in integrated systems, along with their specific and well-established applications. The book offers an overview of recent developments in the field of forward and reverse osmosis and their applications in water desalination, wastewater treatment, power generation and food processing. General principles, membrane module developments, membrane fouling, modeling, simulation and optimization of both technologies are also covered. The book's ultimate goal is to support the scientific community, professionals and enterprises that aspire to develop new applications. - Provides an overview of the advances made in combining reverse osmosis membrane technology and the corresponding forward osmosis - Provides a comprehensive review of advanced research on membrane processes for water desalination, wastewater treatments, etc. - Addresses key issues in process intensification and extraction of energy from renewable sources - Identifies further research needs for the practical implementation of these two membrane technologies
Download or read book Reverse Osmosis written by Zahid Amjad and published by Springer. This book was released on 1993-02-28 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt: This outstanding reference is ideal for those who require in-depth and accurate information about reverse osmosis technology and water chemistry. Professionals in this rapidly expanding field will appreciate the features of this outstanding resource. The book features a full description of the RO process, a comprehensive review of membrane technology and system design, and describes the economic benefits of RO and other desalination technologies. System designers, membrane manufacturers, water purification experts, consultants, separations technologists, and chemical engineers will find Reverse Osmosis an invaluable tool.
Download or read book Reverse Osmosis Concentration of Dilute Pulp Paper Effluents written by Averill J. Wiley and published by . This book was released on 1972 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Real Time Monitoring of Reverse Osmosis Membrane Integrity written by Sirikarn Surawanvijit and published by . This book was released on 2015 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reverse osmosis (RO) membrane desalination is the primary technology for seawater and brackish water desalination, agricultural drainage desalting, as well as municipal wastewater recycling for potable water reuse applications. RO membranes achieve high salt rejection (>95%) and in principle should provide a complete physical barrier to nanosize pathogens (e.g., waterborne enteric viruses). However, in the presence of imperfections and/or membrane damage, membrane breaches as small as 20-30 nm in diameter can allow nanosize pathogens to pass through the membrane and contaminate the product water stream. In order to demonstrate that the level of removal of these contaminants by RO processes will assure rigorous public health protection, there is a need for real-time RO membrane integrity monitoring (MIM). However, at present, reliable real-time RO membrane MIM methods are unavailable for the detection of membrane or module breaches. Given the above needs, a Pulsed Marker Membrane Integrity Monitoring (PM-MIM) approach was developed for real-time assessments of RO membrane integrity, based on characterization of fluorescent molecular marker passage across an RO membrane. This approach involves monitoring the dynamic change in marker concentration in the RO permeate (product) stream in response to a pulsed marker injection into the RO feed stream. The presence and characteristics of membrane integrity loss is identified by decoupling marker diffusive and convective transport through the RO membrane. The approach was first evaluated the passage of a molecular marker through intact and compromised RO membranes (with micron-size membrane breaches) in a bench-scale, plate-and-frame (PFRO) system. It was demonstrated that while marker passage through intact RO membranes was governed by diffusive transport, enhanced marker passage for compromised membranes was associated with convective transport through the breached areas. Therefore, detection of enhanced molecular marker passage was indicative of membrane integrity loss. One of the potential causes of RO membrane integrity loss in RO plants is oxidation of the polyamide RO membrane surface by chlorinated disinfectants, which are typically introduced into the RO feed stream to prevent biofouling. The suitability of the PM-MIM approach for quantification of the extent of membrane integrity loss due to oxidation was evaluated for flat-sheet RO membranes that were degraded via exposure to sodium hypochlorite (NaOCl) solution at various exposure conditions (i.e., NaOCl concentration and exposure time). Upon membrane exposure to 50-200 mg/L NaOCl for a period of 2.5 to 10 hours, there was a significant increase in marker solution-diffusion and convection across the RO membrane as a result of changes in membrane surface physicochemical properties (surface roughness, chemical composition, and wettability) and structural damage (as evident from the presence of micron-size breaches). The severity of membrane integrity loss, represented by an equivalent breach size, increased with chlorine feed concentration and exposure time, with the latter having a more pronounced impact on membrane integrity. In order to implement the PM-MIM approach in full-scale RO plants, which typically consist of multiple spiral-wound RO (SPRO) elements, an analytical framework was developed for characterization of marker passage through RO membranes in each individual SPRO element in multi-element SPRO systems. The approach is based on monitoring and analyzing the dynamic change in the marker concentration in the combined permeate stream (from multiple SPRO elements), in response to a pulsed marker injection into the RO feed. Subsequently, marker convective transport, across the RO membrane in each SPRO element, was be resolved via data fusion of dynamic marker response with online water flow, feed salinity, and pressure data, combined with the estimated marker residence time for each SPRO element. Experimental evaluation, which was carried out with intact and compromised SPRO elements (with mechanically induced membrane breaches), demonstrated enhanced marker passage for compromised SPRO elements, with increased marker passage that correlated with increased breach size. The PM-MIM approach was shown to be both technically and economically suitable for multi-element Ro system and through the proposed protocol for its implementation can serve to quantify the severity and identify the approximate location of membrane integrity loss in a multi-element SPRO plant.
Download or read book Membrane Concentrate Disposal written by Michael C. Mickley and published by . This book was released on 2001 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Efficient Desalination by Reverse Osmosis written by Stewart Burn and published by IWA Publishing. This book was released on 2015-09-15 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Early applications of desalination were small-scale plants deploying a range of technologies. However with the technological developments in Reverse Osmosis, most new plants use this technology because it has a proven history of use and low energy and capital costs compared with other available desalination technologies. This has led to the recent trend for larger seawater desalination plants in an effort to further reduce costs, and 1000 MLD seawater desalination plants are projected by 2020. Efficient Desalination by Reverse Osmosis recognises that desalination by reverse osmosis has progressed significantly over the last decades and provides an up to date review of the state of the art for the reverse osmosis process. It covers issues that arise from desalination operations, environmental issues and ideas for research that will bring further improvements in this technology. Efficient Desalination by Reverse Osmosis provides a complete guide to best practice from pre-treatment through to project delivery. Editors: Stewart Burn, Visiting Scientist, CSIRO Manufacturing. Adjunct Professor, Institute of Sustainability and Innovation, Victoria University. Adjunct Professor, Department of Civil, Environmental and Chemical Engineering, RMIT University. Stephen Gray, Director, Institute of Sustainability and Innovation, Victoria University.
Download or read book Reverse Osmosis written by Fauzi Ismail and published by Elsevier. This book was released on 2018-10-22 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reverse Osmosis starts with an overview of the historic development of the RO membrane, the RO process, and its effect on other membrane separation processes. Other chapters cover the development of nanocomposites of TFC membranes and modern membrane characterization techniques, such as TEM, AFM and PALS, the RO membrane transport model, and RO membrane fouling. The book also describes, in detail, experimental methods for setting up RO experiments, RO membrane modules, RO membrane systems, and desalination and water treatment by RO. Applications in food, pharmaceutical, chemical, biochemical, petroleum and petrochemical industries are also summarized. Other sections cover the development of RO membranes with high thermal and chemical stability, attempts to develop polymeric or inorganic membranes, and hybrid processes where RO is combined with forward osmosis (FO) or membrane distillation (MD). - Written by renowned experts in the field who have complementary expertise - Provides an in-depth discussion of reverse osmosis transport based on nano-level membrane structure - Comprehensively reviews recent progresses in novel reverse osmosis membrane development
Download or read book Integrated Membrane Operations written by Alfredo Cassano and published by Walter de Gruyter. This book was released on 2013-12-12 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive reference work describes in an instructive manner the combination of different membrane operations such as enzyme membrane reactors (EMR's), microfiltration (MF), ultrafiltration (UF), reverse osmosis (RO), nanofiltration (NF) and osmotic distillation (OD) is studied in order to identify their synergistic effects on the optimization of processes in agro-food productions (fruit juices, wines, milk and vegetable beverages) and wastewater treatments within the process intensification strategy. The introduction to integrated membrane operations is followed by applications in the several industries of the food sector, such as valorization of food processing streams, biocatalytic membrane reactors, and membrane emulsification.
Download or read book Reverse Osmosis Membrane Research written by H. Lonsdale and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: Th i s book had its orl gl n in the sympos i urn on "Polymers for Desalination" sponsored by the Division of Polymer Chemistry of the American Chemical Society and held in September, 1971 in Wash ington D. C. at the 162nd national meeting of the Society. However, the book is not simply the proceedings of that symposium. A num ber of additional papers were contributed by other workers in the field, and the original papers presented at the symposium have, for the most part, been expanded. The book thus represents a broad cross section of membrane research and development activities in the United States and abroad within the field of reverse osmosis. The purposes of the book are to bring attention to important new developments in this field, to suggest what the next generation of reverse osmosis equipment may look like, and to indicate where fur ther research and development are needed. The vast majority of the papers collected here represent work supported by the Office of Saline Water of the United States Department of the Interior, and the emphasis here is clearly on the application of the reverse os mosis process to water purification. However, many of the concepts, methods, and conclusions are expected to be useful in other areas of membrane science and technology.
Download or read book Process Feasibility Operational Parameters and Modeling of Reverse Osmosis Membrane Systems for the Separation and Concentration of Hazardous Complex Industrial Wastes written by C. Stewart Slater and published by . This book was released on 1983 with total page 1002 pages. Available in PDF, EPUB and Kindle. Book excerpt:
