Download or read book Concentrate Chemical Softening to Improve the Recovery of Brackish Water Reverse Osmosis Desalination written by Michael Brian Cobb and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Improving Recovery in Reverse Osmosis Desalination of Inland Brackish Groundwaters Via Electrodialysis written by William Shane Walker and published by . This book was released on 2010 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt: As freshwater resources are limited and stressed, and as the cost of conventional drinking water treatment continues to increase, interest in the development of non-traditional water resources such as desalination and water reuse increases. Reverse osmosis (RO) is the predominant technology employed in inland brackish groundwater desalination in the United States, but the potential for membrane fouling and scaling generally limits the system recovery. The general hypothesis of this research is that electrodialysis (ED) technology can be employed to minimize the volume of concentrate waste from RO treatment of brackish water (BW) and thereby improve the environmental and economic feasibility of inland brackish water desalination. The objective of this research was to investigate the performance sensitivity and limitations of ED for treating BWRO concentrate waste through careful experimental and mathematical analysis of selected electrical, hydraulic, and chemical ED variables. Experimental evaluation was performed using a laboratory-scale batch-recycle ED system in which the effects of electrical, hydraulic, and chemical variations were observed. The ED stack voltage showed the greatest control over the rate of ionic separation, and the specific energy invested in the separation was approximately proportional to the applied voltage and equivalent concentration separated. An increase in the superficial velocity showed marginal improvements in the rate of separation by decreasing the thickness of the membrane diffusion boundary layers. A small decrease in the nominal recovery was observed because of water transport by osmosis and electroosmosis. Successive concentration of the concentrate by multiple ED stages demonstrated that the recovery of BWRO concentrate could significantly improve the overall recovery of inland BWRO systems. A mathematical model for the steady-state performance of an ED stack was developed to simulate the treatment of BWRO concentrates by accounting for variation of supersaturated multicomponent solution properties. A time-dependent model was developed that incorporated the steady-state ED model to simulate the batch-recycle experimentation. Comparison of the electrical losses revealed that the electrical resistance of the ion exchange membranes becomes more significant with increasing solution salinity. Also, a simple economic model demonstrated that ED could feasibly be employed, especially for zero-liquid discharge.

Download or read book Improved Concentrate Recovery for Brackish Water Reverse Osmosis written by Scott Henry Hekman and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book High Recovery Desalination of Brackish Water by Chemically enhanced Seeded Precipitation written by Brian Carey McCool and published by . This book was released on 2012 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: Various regions around the world are confronted with dwindling water supplies and thus the need for exploiting non-traditional inland brackish water resource, as well as reclamation and reuse of municipal wastewater and agricultural drainage (AD) water. Reverse osmosis (RO) membrane desalination is the primary technology for inland brackish water desalting. However, successful implementation of RO technology requires operation at high product water recovery (>85%) in order to minimize the volume of generated concentrate (i.e., brine). Brine management is a key factor governing the economics of inland water desalination. Therefore, brine volume reduction is critical to enabling various brine residual management options. At high water recovery, dissolved mineral salts (e.g., CaSO4, BaSO4, CaCO3) may become concentrated above their solubility limits and may crystallize in the bulk and onto the surface of the RO membranes. Mineral crystallization leads to membrane scaling and hence leads to flux decline, increased process costs, and shortening of membrane life. Therefore, the attainable desalination water recovery is limited by mineral scaling. Many inland brackish water sources contain high concentrations of sparingly soluble mineral salts. In certain areas, such as in California's San Joaquin Valley (SJV), brackish water is near saturation with respect to calcium sulfate and barium sulfate. Based on the current work, single-stage RO desalination in SJV would generally be limited to ~50-70%. In order to desalt brackish water of high mineral scaling propensity at a high recovery level (>85%), the feasibility of intermediate concentrate demineralization (ICD) of primary RO (PRO) concentrate, as a means of enabling secondary RO (SRO) desalting, was investigated with a focus on brackish water having high concentrations of gypsum salt precursor ions (i.e., calcium and sulfate). Accordingly, a two-step chemically-enhanced seeded precipitation (CESP) ICD process was developed in which the PRO concentrate is treated prior to further SRO desalting. The first step is lime precipitation softening (PS) which serves to induce sufficient CaCO3 crystallization in order to remove residual antiscalant (AS), a PRO feed treatment additive (generally polymeric) used for scale control, that would otherwise inhibit precipitation (in the ICD) of the target mineral salt scalants. Subsequently, gypsum seeded precipitation (GSP) is carried out to reduce the level of calcium sulfate saturation. The CESP process was evaluated experimentally, in a batch crystallizer, using synthetic PRO concentrate and also PRO concentrate generated in the field, from AD water, using a spiral-wound RO pilot plant. The effect of residual AS (from the PRO stage) on retardation of mineral salt precipitation (in the ICD) was evaluated using both a generic (polyacrylic acid) and a commercial AS. Laboratory batch CESP studies were carried out in which the CESP process conditions were first optimized with respect to the required lime and gypsum seed doses. For raw brackish water that was about 98% saturated with respect to gypsum, PRO desalination at 52%-62% recovery yielded a brine stream 70-150% above saturation. CESP treatment, at lime doses of 0.25-0.35 mg/L and gypsum seeding of 4-5 g/L, enabled reduction of gypsum concentration to only 10-15% above its saturation. In general, the sequential processes of lime treatment for 10-20 minutes followed by ~1 hr of GSP were sufficient to achieve the above level of gypsum desupersaturation. GSP alone reduced gypsum saturation by only ~5%. PRO brine desupersaturation via CESP was feasible due to the effectiveness of AS removal (up to 90% for AS content of up to 10 mg/L in the PRO brine). Analysis of AS removal using a fundamental AS adsorption model, along with measurements of the size distribution of precipitating CaCO3 crystals, indicated that the area for AS adsorption provided by lime-induced nucleation of CaCO3 crystals is the key factor governing AS removal. In order to establish the feasibility of deploying CESP as a continuous process, a numerical model was developed for a fluidized bed reactor for the GSP stage. Model simulations indicated that the required level of calcium sulfate desupersaturation could be maintained by solids recycling leading to a steady-state particle size distribution. Process simulations and economic analysis were carried out for the integrated process of PRO, CESP and SRO (PRO-CESP-SRO) demonstrating the existence of an optimal recovery (with respect to product water treatment cost). For the evaluated SJV brackish AD water source, the optimal recovery was about 93%. Overall brackish water treatment cost, when considering the disposal cost of high salinity AD water, was lower for PRO-CESP-SRO relative to a similar process based on conventional PS or utilizing a single stage RO which would be of limited recovery (

Download or read book Sustainable Desalination and Water Reuse written by Eric M.V. Hoek and published by Springer Nature. This book was released on 2022-05-31 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past half century, reverse osmosis (RO) has grown from a nascent niche technology into the most versatile and effective desalination and advanced water treatment technology available. However, there remain certain challenges for improving the cost-effectiveness and sustainability of RO desalination plants in various applications. In low-pressure RO applications, both capital (CAPEX) and operating (OPEX) costs are largely influenced by product water recovery, which is typically limited by mineral scale formation. In seawater applications, recovery tends to be limited by the salinity limits on brine discharge and cost is dominated by energy demand. The combination of water scarcity and sustainability imperatives, in many locations, is driving system designs towards minimal and zero liquid discharge (M/ZLD) for inland brackish water, municipal and industrial wastewaters, and even seawater desalination. Herein, we review the basic principles of RO processes, the state-of-the-art for RO membranes, modules and system designs as well as methods for concentrating and treating brines to achieve MLD/ZLD, resource recovery and renewable energy powered desalination systems. Throughout, we provide examples of installations employing conventional and some novel approaches towards high recovery RO in a range of applications from brackish groundwater desalination to oil and gas produced water treatment and seawater desalination.

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 Desalination by Reverse Osmosis written by Ulrich Merten and published by . This book was released on 1966 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Enhancing Recovery of Reverse Osmosis Desalination written by Lauren Fay Greenlee and published by . This book was released on 2009 with total page 548 pages. Available in PDF, EPUB and Kindle. Book excerpt: Brackish waters are now considered valuable alternative water resources. Reverse osmosis (RO) membranes are the most promising candidate for drinking water production through desalination. Low recovery (the fraction of influent water that becomes product water) prevents widespread application of RO inland because of the high cost of waste disposal. The recovery of a brackish RO system is limited by sparingly soluble salts that become supersaturated and precipitate on the membrane surface. Precipitation is controlled through pH adjustment and antiscalant addition; however, at high salt supersaturation, antiscalant control is overcome and precipitation occurs. To further increase RO recovery and avoid precipitation, a three-stage process treated the waste stream (concentrate) of a brackish water RO system through antiscalant degradation, salt precipitation, and solid/liquid separation. Ozone (O3) and hydrogen peroxide (H2O2) were used to degrade antiscalants, pH elevation and base (NaOH/NaHCO3) addition were used to precipitate sparingly soluble salts, and microfiltration (0.1 [mu]m) was used to separate precipitated solids from the water. Optimal parameters (pH, ozone dose, H2O2/O3 ratio, antiscalant type and concentration, water composition) for antiscalant oxidation were determined. The influence of antiscalant type and concentration and pH was investigated for the precipitation and filtration stages. Results were obtained for particle size distribution, extent of precipitation, particle morphology, and particle composition. The effect of ozonation on precipitation and filtration was evaluated, with a comparison to two-stage treatment consisting of precipitation and filtration. Antiscalant oxidation is controlled by bivalent cation coordination, while pH and ozone dose significantly affect the extent of oxidation. The addition of antiscalant prior to precipitation caused changes to particle size and morphology, and results varied with water composition and antiscalant type and concentration. Ozonation, even for small times such as one minute, prior to precipitation and filtration increased calcium precipitation and decomposed the antiscalant enough to remove the effect of the antiscalant on particle characteristics. During ozonation, antiscalants were not completely oxidized, but the partial oxidation products did not seem to affect precipitation. Ozonation also reduced the fouling of microfiltration membranes used for solid/liquid separation. Results indicated concentrate treatment can significantly increase the overall recovery of an RO system.

Download or read book Pretreatment for Reverse Osmosis Desalination written by Nikolay Voutchkov and published by Elsevier. This book was released on 2017-05-29 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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

Download or read book Membrane Desalination of Agricultural Drainage Water written by Yoram Cohen and published by . This book was released on 2008 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling Recovery Pressure and Product Concentration for Brackish Water Reverse Osmosis written by Devikaa Rajaraman and published by . This book was released on 2011 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Desalination of Seawater and Brackish Water written by American Water Works Association and published by . This book was released on 2006 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt: Part of the AWWA Trend Series, this is a compilation of the most significant published works on desalination from January 2001-March 2004. Articles are taken from AWWA conference proceedings and periodicals and include some updated material not previously published. Major topics are seawater and brackish desalination, membrane softening, disposal, costs and delivery.

Download or read book Principles of Water Treatment written by Kerry J. Howe and published by John Wiley & Sons. This book was released on 2012-11-06 with total page 674 pages. Available in PDF, EPUB and Kindle. Book excerpt: Principles of Water Treatment has been developed from the best selling reference work Water Treatment, 3rd edition by the same author team. It maintains the same quality writing, illustrations, and worked examples as the larger book, but in a smaller format which focuses on the treatment processes and not on the design of the facilities.

Download or read book Reverse Osmosis Seawater Desalination Volume 1 written by Heinz Ludwig and published by Springer Nature. This book was released on 2022-10-29 with total page 749 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Treatise on Water Science written by and published by Newnes. This book was released on 2010-09-01 with total page 2131 pages. Available in PDF, EPUB and Kindle. Book excerpt: Water quality and management are of great significance globally, as the demand for clean, potable water far exceeds the availability. Water science research brings together the natural and applied sciences, engineering, chemistry, law and policy, and economics, and the Treatise on Water Science seeks to unite these areas through contributions from a global team of author-experts. The 4-volume set examines topics in depth, with an emphasis on innovative research and technologies for those working in applied areas. Published in partnership with and endorsed by the International Water Association (IWA), demonstrating the authority of the content Editor-in-Chief Peter Wilderer, a Stockholm Water Prize recipient, has assembled a world-class team of volume editors and contributing authors Topics related to water resource management, water quality and supply, and handling of wastewater are treated in depth

Download or read book Reverse Osmosis Seawater Desalination Volume 2 written by Heinz Ludwig and published by Springer Nature. This book was released on 2022-10-29 with total page 641 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.