Particulate and Organic Matter Fouling of Seawater Reverse Osmosis Systems


Book Description

Characterizing bulk organic matter in seawater and bay water by various analytical techniques and linking these measurements with fouling in membrane systems. Furthermore, it aimed for the development of the Modified Fouling Index - ultrafiltration (MFI-UF) at constant flux filtration as an accurate test to measure the particulate fouling potential of a feed water and predict the rate of fouling in reverse osmosis systems. A new semi-portable set-up has been successfully developed to perform MFI-UF tests at constant flux filtration. A significant effect of the filtration flux on the fouling potential was found. Consequences of this effect for reverse osmosis systems are that the fouling potential at low flux drops dramatically; for ultrafiltration systems it implicates that the rate of fouling increases at high fluxes. The observed effect of flux on the fouling potential has significant implications for fouling potential measurements. Deposition factors in RO systems varied between 0 and 1, depending on location and MFI pore size, which indicates differences in properties of the particles present. Fouling potential results in RO fouling rates of 0.2-1 bar/month depending on the pore size of the membranes used for MFI measurements. The fouling potential of the analysed raw waters is substantially reduced by conventional pre-treatment systems and ultrafiltration: for conventional pre-treatment 37 % - 74 % and ultrafiltration 60 % - 95 %, depending on the location and the MFI pore size.




Controlling Biofouling in Seawater Reverse Osmosis Membrane Systems


Book Description

Seawater desalination is a rapidly growing coastal industry that is increasingly threatened by algal blooms. Depending on the severity of algal blooms, desalination systems may be forced to shut down because of clogging and/or poor feed water quality. To maintain stable operation and provide good feed water quality to seawater reverse osmosis (SWRO) systems, ultrafiltration (UF) pre-treatment is proposed. This research focused on assessing the ability of UF and other pre-treatment technologies to reduce biofouling in SWRO systems. An improved method to measure bacterial regrowth potential (BRP) was developed and applied at laboratory, pilot and full scale to assess the ability of conventional UF (150 kDa) and tight UF (10 kDa) alone and in combination with a phosphate adsorbent to reduce regrowth potential and delay the onset of biofouling in SWRO. The improved bacterial regrowth potential method employs a natural consortium of marine bacteria as inoculum and flow cytometry. The limit of detection of the BRP method was lowered to 43,000 ± 12,000 cells/mL, which is equivalent to 9.3 ± 2.6 μg-Cglucose/L. The reduction in bacterial regrowth potential after tight UF (10 kDa) was 3 to 4 times higher than with conventional UF (150 kDa). It was further reduced after the application of a phosphate adsorbent, independent of pore size of the UF membrane. Pilot studies demonstrated that the application of tight UF (10 kDa) coupled with a phosphate adsorbent consistently lowered the bacterial regrowth potential and no feed channel pressure drop increase was observed in membrane fouling simulators (MFS) over a period of 21 days. The study also showed that non-backwashable fouling of UF membranes varied strongly with the type of algal species and the algal organic matter (AOM) they release. The presence of polysaccharide (stretching -OH) and sugar ester groups (stretching S=O) was the main cause of non-backwashable fouling. In conclusion, this study showed that an improved BRP method is suitable for the assessment of SWRO pre-treatment systems and it can be a useful tool to develop potential strategies to mitigate biofouling and improve the sustainability of SWRO systems.




Seawater Reverse Osmosis Desalination


Book Description

Desalination as a method to provide clean drinking water has become vital – particularly in a context where drought, water scarcity and rapid quality decrease of water bodies have become an undeniable reality. After more than half a century of membrane-based desalination, fouling and scaling is still a dominant challenge. In membrane technologies, in particular, fouling and scaling are a major issue with respect to design, operation, reliability of the technologies and cost. This textbook covers theory and practice and is intended for designers, operators, consultants, suppliers and students. Principles of ultra- and nanofiltration and reverse osmosis (RO) are discussed, enabling the reader to understand the link between design, operation and fouling and scaling. Fouling (particulate, organic -including algal bloom events, inorganic, and biofouling) and scaling are treated in detail, including parameters to determine fouling and scaling potential of feed waters. Principles of conventional and advanced pre-treatment processes are highlighted and their effect on preventing fouling and scaling. In addition, the process design of RO systems and the recent advances in seawater RO and emerging membrane-based processes for seawater desalination are presented.




Reverse Osmosis Seawater Desalination Volume 1


Book Description

Seawater reverse osmosis (SWRO) is the dominant desalination process worldwide for obtaining fresh water from the sea. The subject matter and scope of this book is the conceptual and advanced planning, design and engineering of plants of this desalination process together with the associated facilities for seawater pretreatment, post-treatment of the product water, wastewater treatment, seawater extraction and plant discharge. The book is intended to be used by technicians, engineers, economists and ecologists in the planning, design and operation of SWRO plants, as an educational and training tool, as well as an aid in environmental licensing of membrane desalination plants, and by interested laypersons for information about this process. The two volumes are also available as a set.




Pretreatment for Reverse Osmosis Desalination


Book Description

Pretreatment for Reverse Osmosis Desalination is a comprehensive reference on all existing and emerging seawater pretreatment technologies used for desalination. The book focuses on reverse osmosis membrane desalination, which at present is the most widely applied technology for the production of fresh drinking water from highly saline water sources (brackish water and seawater). Each chapter contains examples illustrating various pretreatment technologies and their practical implementation. Provides in-depth overview of the key theoretical concepts associated with desalination pre-treatment Gives insight into the latest trends in membrane separation technology Incorporates analytical methods and guidelines for monitoring pretreatment systems




Assessing Bacterial Growth Potential in Seawater Reverse Osmosis Pretreatment


Book Description

Seawater desalination is increasingly being used as a means to augment freshwater supplies in regions with high water stress, and reverse osmosis is increasingly the technology of choice because of the low energy consumption. However, seawater reverse osmosis (SWRO) systems suffer from various types of fouling, which can increase energy consumption and the use of chemicals during SWRO operation. In practice, pre-treatment systems are put in place to reduce the particulate and biological fouling potential of SWRO feed water. However, simple, reliable and accurate methods to assess the extent to which biological fouling potential is reduced during pre-treatment are not available for seawater. This research developed a new method to measure bacterial growth potential (BGP) using the native bacterial consortium in seawater. New reagents to extract and detect ATP in microbial cells were specifically developed for seawater. The new lysis and detection reagents overcame the salt interference in seawater and allow low detection of total ATP, free ATP and microbial ATP in seawater. Incorporating a filtration step further increased the sensitivity of the method six fold, enabling ATP detection of ultra-low levels of microbial ATP in seawater. The newly developed ATP-based BGP method was applied to monitor and assess the pre-treatment of five full-scale seawater desalination plants around the world. A good correlation was observed between BGP measured in SWRO feed water and the pressure drop increase in the SWRO systems, suggesting the applicability of using the ATP-based BGP method as a biofouling indicator in SWRO. Furthermore, a safe level of BGP ( In the future, on-line monitoring of BGP in SWRO feed water may further reduce the consumption of chemicals and energy and improve the overall sustainability of seawater desalination by reverse osmosis.




Osmosis Engineering


Book Description

Osmosis Engineering provides a comprehensive overview of the state-of-the-art surrounding osmosis-based research and industrial applications. The book covers the underpinning theories, technology developments and commercial applications. Sections discuss innovative and advanced membranes and modules for osmosis separation processes (e.g., reverse osmosis, forward osmosis, pressure retarded osmosis, osmotic membrane distillation), different application of these osmosis separation processes for energy and water separation, such as the treatment of radioactive waste, oily wastewater and heavy metal removal, draw solutions, pretreatment technologies, fouling effects, the use of renewable energy driven osmotic processes, computational, environmental and economic studies, and more. Covers state-of-the-art osmotic engineering technologies and applications Presents multidisciplinary topics in engineered osmosis, including both fundamental and applied EO concepts Includes major challenges such as fouling mitigation, membrane development, pre-treatment and energy usage




Removal of Pollutants from Saline Water


Book Description

Removal of Pollutants from Saline Water: Treatment Technologies provides a comprehensive understanding of technologies that are currently adopted in the treatment of pollutants present in saline water systems. It provides information on the treatment technologies for saline water systems, including seawater, brackish water, oil-produced water, and other industrial saline wastewaters. FEATURES Presents information exclusively for saline water pollutant removal Introduces current treatment technologies and addresses why and how the techniques differ between fresh and salt water Offers an inclusive overview of physicochemical, biological, membrane, and advanced oxidation treatment technologies Features various perspectives and case studies from relevant global experts Provides a comprehensive one-stop source for the treatment of pollutants in all saline water systems Aimed at students, academicians, researchers, and practicing engineers in the fields of chemical, civil, marine, and environmental engineering who wish to be acquainted with the most recent developments in the treatment of pollutants present in saline water systems. Prof. Dr. Shaik Feroz works at Prince Mohammad Bin Fahd University, Kingdom of Saudi Arabia. He has 30 years of experience in teaching, research, and industry. He has more than 190 publications to his credit in journals and conferences of international repute. He was awarded "Best Researcher" by Caledonian College of Engineering for the year 2014. Prof. Dr. Detlef W. Bahnemann is Head of the Research Unit, Photocatalysis and Nanotechnology at Leibniz University Hannover (Germany), Director of the Research Institute "Nanocomposite Materials for Photonic Applications" at Saint Petersburg State University (Russian Federation), and Distinguished Professor at Shaanxi University of Science and Technology in Xi’an (People's Republic of China). His research topics include photocatalysis, photoelectrochemistry, solar chemistry, and photochemistry focused on synthesis and physical-chemical properties of semiconductor and metal nanoparticles. His 500-plus publications have been cited more than 65,000 times (h-index: 100).




Reverse Osmosis Systems


Book Description

Reverse Osmosis Systems: Design, Optimization and Troubleshooting Guide describes in depth knowledge of designing and operating reverse osmosis (RO) systems for water desalination, and covers issues which will effect the probability for the long-standing success of the application. It also provides guidelines that will increase the performance of seawater RO desalination systems by avoiding errors in the design and operation and suggest corrective measures and troubleshooting of the problems encountered during RO operation. This book also provides guidelines for the best RO design and operational performance. In the introductory section, the book covers the history of RO along with the fundamentals, principles, transport models, and equations. Following sections cover the practical areas such as pretreatment processes, design parameters, design software programs (WAVE, IMSDesign, TORAYDS2, Lewaplus, ROAM Ver. 2.0, Winflows etc.), RO performance monitoring, normalization software programs (RODataXL and TorayTrak), troubleshooting as well as system engineering. Simplified methods to use the design software programs are also properly illustrated and the screenshots of the results, methods etc. are also given here along with a video tutorial.The final section of the book includes the frequently asked questions along with their answers. Moreover, various case studies carried out and recent developments related to RO system performance, membrane fouling, scaling, and degradation studies have been analyzed. The book also has several work out examples, which are detailed in a careful as well as simple manner that help the reader to understand and follow it properly. The information presented in some of the case studies are obtained from existing commercial RO desalination plants. These topics enable the book to become a perfect tool for engineers and plant operators/technicians, who are responsible for RO system design, operation, maintenance, and troubleshooting. With the right system design, proper operation, and maintenance program, the RO system can offer high purity water for several years. Provides guidelines for the optimum design and operational performance of reverse osmosis desalination plants Presents step-by-step procedure to design reverse osmosis system with the latest design software programs along with a video tutorial Analyzes some of the issues faced during the design and operation of the reverse osmosis desalination systems, suggest corrective measures and its troubleshooting Discusses reverse osmosis desalination pretreatment processes, design parameters, system performance monitoring, and normalization software programs Examines recent developments related to system performance, membrane fouling, and scaling studies Presents case studies related to commercial reverse osmosis desalination plants Perfect training guide for engineers and plant operators, who are responsible for reverse osmosis system design, operation and maintainance




Membrane Based Desalination


Book Description

Reverse osmosis is the dominant technology in water desalination. However, some critical issues remain open: improvement of water quality, enhancement of the recovery factor, reduction of the unit water cost, minimizing the brine disposal impact. This book aims to solve these problems with an innovative approach based on the integration of different membrane operations in pre-treatment and post-treatment stages. Membrane-Based Desalination: An Integrated Approach (acronym MEDINA) has been a three year project funded by the European Commission within the 6th Framework Program. The project team has developed a work programme aiming to improve the current design and operation practices of membrane systems used for water desalination, trying to solve or, at least, to decrease the critical issues of sea and brackish water desalination systems. In the book, the main results achieved in the nine Work Packages constituting the project will be described, and dismissed by the leaders of the various WPs. The following areas are explored in the book: the development of advanced analytical methods for feed water characterization, appropriate fouling indicators and prediction tools, procedures and protocols at full-scale desalination facilities; the identification of optimal seawater pre-treatment strategies by designing advanced hybrid membrane processes (submerged hollow fibre filtration/reaction, adsorption/ion exchange/ozonation) and comparison with conventional methods; the optimisation of RO membrane module configuration, cleaning strategies, reduction of scaling potential by NF; the development of strategies aiming to approach the concept of Zero Liquid Discharge (increasing the water recovery factor up to 95% by using Membrane Distillation - MD; bringing concentrates to solids by Membrane Crystallization or Wind Intensified Enhanced Evaporation) and to reduce the brine disposal environmental impact and cost; increase the sustainability of desalination process by reducing energy consumption (evaluation of MD, demonstration of a new energy recovery device for SWRO installations) and use of renewable energy (wind and solar). Colour figures (PDF, 6MB) Visit the IWA WaterWiki to read and share material related to this title: http://www.iwawaterwiki.org/xwiki/bin/view/Articles/WaterdesalinationandEuropeanresearch