High-recovery Electrodialysis Reversal for the Desalination of Inland Brackish Waters PDF Download

Author: Connor Patrick Hanrahan
Publisher:
ISBN:
Category : Saline water conversion
Languages : en
Pages : 200

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Author: Masoume Jaberi
Publisher:
ISBN:
Category : Brackish waters
Languages : en
Pages : 240

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Book Description
The worsening global scarcity of freshwater threatens worldwide peace and prosperity, which are intimately tied to the availability of clean, fresh water (J. E. Miller, 2003). One approach for alleviating this threat is desalination, which can turn brackish and saline water sources into freshwater, and electrodialysis reversal (EDR) is a proven and widely used technology that can desalinate brackish waters in inland areas such as the southwestern United States. In a significant advantage over other membrane-based systems like reverse osmosis, EDR's ability to clean itself renders the system resistant to scaling and fouling and allows it to operate at high levels of water recovery. In a further benefit, this system typically requires less energy than thermal distillation to desalinate brackish water, leading to a reduction in overall desalination costs. To identify the operating limits of EDR and find the parameters that maximize its performance, this research investigated the performance sensitivity and limitations of EDR for treating brackish groundwater through careful experimental and statistical analyses of selected electrical, hydraulic, and chemical variables. Experimental evaluation was performed using a pilot-scale EDR system and natural feedwaters at the Brackish Groundwater National Desalination Research Facility in Alamogordo, NM; statistical analyses were carried out using SAS software. Based on the experimental results and statistical analyses, multi-linear regression models were developed for EDR systems for removal ratio, current, and specific energy consumption.

Author: William Shane Walker
Publisher:
ISBN:
Category :
Languages : en
Pages : 374

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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.

Author: Brian Carey McCool
Publisher:
ISBN:
Category :
Languages : en
Pages : 208

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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 (

Author: Eric M.V. Hoek
Publisher: Springer Nature
ISBN: 3031795083
Category : Technology & Engineering
Languages : en
Pages : 194

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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.

Author: Noe Ortega-Corral
Publisher:
ISBN:
Category : Atomic force microscopy
Languages : en
Pages :

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Author: American Water Works Association
Publisher: American Water Works Association
ISBN: 0898677688
Category : Technology & Engineering
Languages : en
Pages : 63

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This manual provides information on electrodialysis and electrodialysis reversal technologies in water treatment. This clearly written manual explains principles of operation, applications for water treatment, equipment, system design, costs, pretreatment and posttreatment, installation, operation, maintenance, and disposal of concentrate.

Author: Alireza Bazargan
Publisher: CRC Press
ISBN: 1000793648
Category : Technology & Engineering
Languages : en
Pages : 716

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Book Description
Although more than 70% of the globe is covered with water, only a small portion is suitable for direct human use, making the scarcity of freshwater one of our plant's most serious challenges. In this context "desalination", defined as "the removal of salt from water", is one of the possible solutions for overcoming our planet's municipal and industrial thirst. By drawing upon the authoritative expertise of a remarkable team of international authors, this book aims to provide an encompassing and "multidisciplinary" introduction to various aspects of desalination. The forte of this publication is that it does not overtly focus on a particular sub-topic of desalination, but rather addresses the topic as a whole. In other words, the unique assortment of reader-friendly chapters is designed to strike a delicate balance between the technical and non-technical. The book is divided into five general sections:The first section presents an overview of water scarcity, followed by a review of integrated water management and the alternatives to desalination. The fundamentals of desalination are provided, including simple water chemistry;The second section covers the conventional technologies of today, including thermal and membrane desalination processes. The topics of pre- and post- treatment are given due credit, as no desalination plant can operate without them;The third section reviews the history of how desalination technologies originated, including a review of today's R&D activities and cutting edge research. The processes and engineering applied for membrane manufacturing are also presented;Section four is concerned with energy and environmental issues, including the application of renewable and nuclear energy, minimization of energy usage and the water-energy-nexus, brine management, and environmental impacts;Finally, section five covers the social and commercial issues, ranging from rural desalination, to the politics of desalination. Desalination costs and feasibility are presented, as well as issues in business development and the future market prospects.Effectively, A Multidisciplinary Introduction to Desalination aims to be a holistic go-to-compendium for anyone seeking a balanced understanding of the various facets of desalination

Author: AWWA Staff
Publisher: American Water Works Association
ISBN: 1613001673
Category : Technology & Engineering
Languages : en
Pages : 62

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This manual provides information on electrodialysis and electrodialysis reversal technologies in water treatment. This clearly written manual explains principles of operation, applications for water treatment, equipment, system design, costs, pretreatment and posttreatment, installation, operation, maintenance, and disposal of concentrate.

Author: Lauren Fay Greenlee
Publisher:
ISBN:
Category :
Languages : en
Pages : 548

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Book Description
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.