Abstract: The present disclosure describes systems and methods for wastewater treatment. In some embodiments, a system may include one or more of a pair of electrodes, a first membrane selectively permeable to a first wastewater nutrient, a second membrane selectively permeable to a second wastewater nutrient, and at least one spacing frame comprising a structural element, a gasket, and a flow channel. In some embodiments, the system may further include a septic tank.

Abstract: Provided are water treatment systems and methods of treating water that include separating dissolved salts from a feed stream using an organic solvent brine stream. For example, described are water treatment systems comprising: an electrodialysis device comprising an inlet feed stream, an inlet brine stream, an outlet product stream, and an outlet brine stream; and a precipitation tank comprising an inlet stream and an outlet stream, wherein the inlet stream of the precipitation tank comprises the outlet brine stream of the electrodialysis device, and the inlet brine stream of the electrodialysis device comprises the outlet stream of the precipitation tank, and wherein inlet brine stream and outlet brine stream comprises an organic solvent.

Abstract: A bipolar membrane electrodialysis method and system are described for purifying an organic acid from an aqueous solution containing the salt of the organic acid. The system includes a bipolar membrane electrodialysis stack that includes at least one three-compartment bipolar membrane electrodialysis cell and at least one two-compartment bipolar membrane electrodialysis cell. The method includes recirculating the solution of organic acid produced from the three-compartment bipolar membrane electrodialysis cell and two-compartment bipolar membrane electrodialysis cell. Cation or anion exchange resins may be included in the spacers of acid compartment to increase the conductivity of acid compartments, thereby increasing current density of the bipolar electrodialysis stack and decreasing power consumption.

Abstract: The method for purifying oses from hemicellulose originating from lignocellulosic biomass includes eliminating the cellulose matrix and the solid residues and/or the suspended materials from the acid hydrolysate containing oses in order to obtain a clarified hydrolysate, and subjecting the clarified hydrolysate, without adding any basic chemical reagent to increase the pH to at least one step of ultrafiltration and/or to at least one step of nanofiltration, so as to obtain a filtrate containing the majority of the pentoses and a retentate containing the species likely to precipitate under the effect of an increase in the pH. The filtrate is treated by at least one step of electrodialysis so as to recover the acid catalyst from an acid-supplemented solution, and obtain a deacidified filtrate.

Abstract: Methods for controlling electrolyte chemistry in electrodialysis units having an anode and a cathode each in an electrolyte of a selected concentration and a membrane stack disposed therebetween. The membrane stack includes pairs of cationic selective and anionic membranes to segregate increasingly dilute salts streams from concentrated salts stream. Electrolyte chemistry control is via use of at least one of following techniques: a single calcium exclusionary cationic selective membrane at a cathode cell boundary, an exclusionary membrane configured as a hydraulically isolated scavenger cell, a multivalent scavenger co-electrolyte and combinations thereof.

Abstract: In one embodiment, this invention relates to an electrodialysis device comprising an inlet for directing a feed stream into a plurality of first feed paths and a plurality of second feed paths; the feed stream is comprised of a first anionic scaling species and a first cationic scaling species; the first cationic scaling species is transferred from the second feed paths to the first feed paths through a first membrane group, the first anionic scaling species is transferred from the first feed paths to the second feed paths through the first membrane group. In another embodiment, this invention relates to a method for passivating scaling species in an electrodialysis device.

Abstract: In one embodiment, this invention relates to an electrodialysis device comprising an inlet for directing a feed stream into a plurality of first feed paths and a plurality of second feed paths; the feed stream is comprised of a first anionic scaling species and a first cationic scaling species; the first cationic scaling species is transferred from the second feed paths to the first feed paths through a first membrane group, the first anionic scaling species is transferred from the first feed paths to the second feed paths through the first membrane group. In another embodiment, this invention relates to a method for passivating scaling species in an electrodialysis device.

Abstract: A process for producing ultrapure water, in which a stream of water is purified in a reverse osmosis device, wherein the water stream is subject to pretreatment including splitting the water stream into at least two partial streams, partial exchange of cations present in at least one of the partial streams for H+ ions by a cation exchanger operated in the H+ mode, and complete exchange of the anions present in at least one further of the partial streams for OH? ions by a softener operative in parallel to the cation exchanger, and treating the partial streams treated by the cation exchanger and the softener by at least one anion exchanger operating in the OH? mode, and wherein the water stream obtained from the pretreatment is fed into the reverse osmosis device.

Abstract: A method and a system for process parameter control of a liquid composition in a reverse electro-enhanced dialysis (REED) system comprising at least two Reverse Electro-Enhanced Dialysis (REED) membrane stacks, wherein the direction of the electric field within any one membrane stack is reversed at asynchronical intervals of time relative to the current reversals for any other membrane stack.

Abstract: A treatment system provides treated or softened water to a point of use by removing at least a portion of any undesirable species contained in water from a water source. The treatment system can be operated to reduce the likelihood of formation of any scale that can be generated during normal operation of an electrochemical device. The formation of scale in the treatment system, including its wetted components, may be inhibited by reversing or substituting the flowing liquid having hardness-causing species with another liquid having a low tendency to produce scale, such as a low LSI water. Various arrangements of components in the treatment system can be flushed by directing the valves and the pumps of the system to displace liquid having hardness-causing species with a liquid that has little or no tendency to form scale.

Abstract: Method for the removal of ions and ionizable substances from a polar liquid (10) comprising at least one process wherein said polar liquid (10) is split into a first stream (F1) and a second stream (F2), Said first stream (F1) passing through an electrochemically regenerable ion-exchange material (2) located where an electric field between two electrodes (4, 5) is applied, said first stream (F1) flowing from one electrode (4) to the other electrode (5) so that the ions to be removed are migrating in the direction reverse to the first stream flow through said ion-exchange material (2), Said second stream (F2) rinsing said one electrode (4), and said material is regenerated by the ions which are formed at the other electrode (5). Device in particular for the implementation of said method.

Abstract: A method and system are described to treat ammonia-containing wastewater or process waters. Sewage containing human or animal waste and certain process liquids, typically water, contains high levels of nitrogen in the form of ammonia. An electro-chemical method to extract the ammonia from the wastewater is also described. The system described is one implementation of this method. One or more electrolysis cells convert ammonium to ammonia where the generated ammonia gas can readily be extracted for disposal or reuse. Such a system can involve electrolysis cells of numerous types as described herein.

Abstract: An electrolyzing device is capable of removing scales adhered to a cathode in an electrolyzing mode without deteriorating an electrode forming an anode. An electrolyzing device includes a first main electrode 3, a second main electrode 4, an auxiliary electrode 5, and control means C for controlling current supply to the electrodes, the control means C includes an electrolyzing mode in which treated water is electrochemically treated by using the first main electrode 3 as an anode and the second main electrode 4 as a cathode, a scale removal mode of the second main electrode in which scales adhered to the second main electrode 4 are removed by using the second main electrode 4 as the anode and the auxiliary electrode 5 as the cathode, and a scale removal mode of the auxiliary electrode in which scales adhered to the auxiliary electrode 5 are removed by using the auxiliary electrode 5 as the anode and the second main electrode 4 as the cathode.

Abstract: An electrically and ionically conductive porous material including a thermoplastic binder and one or more of anion exchange moieties or cation exchange moieties or mixtures thereof and/or one or more of a protein capture resin and an electrically conductive material. The thermoplastic binder immobilizes the moieties with respect to each other but does not substantially coat the moieties and forms the electrically conductive porous material. A wafer of the material and a method of making the material and wafer are disclosed.

Abstract: Desalination is carried out by a hybrid ion exchange-nanofiltration process in which ion exchange is followed by pressure-driven nanofiltration. Monovalent ions of sodium and chloride of saline water are exchanged for equivalent concentrations of poly-valent ions (for example, sodium ions for magnesium ions or chloride ions for sulfate ions) when passed through ion exchangers in the form of those poly-valent ions. The resultant solution has a lower osmotic pressure than the initial solution containing monovalent sodium and chloride ions, and requires less transmembrane pressure for membrane desalination compared to traditional reverse osmosis. The concentrated reject stream from the membrane process is used as regenerant for the exhausted ion exchanger, which has been converted to monovalent anionic or cationic form.

Abstract: The disclosed techniques involve electrical separation systems that allow recovery of species from feedstreams, typically aqueous solutions. The disclosed techniques can also provide electrical separation systems having reduced tendency to form scale especially when water is being purified to reduce the concentration of hardness-causing species.

Abstract: An improved apparatus and operating method related thereto for deionizing water to produce substantially pure water using electric field and ion exchange materials are disclosed, including embodiments incorporating one or more of the novel features of brine and electrode streams flowing in a direction counter-current to the stream being deionized, a filling of the brine stream with stratified ion exchange materials, a stream mixing feature for mixing the stream being deionized, a gas removal feature for removal of gases, a spiral-wound embodiment of an electrodialysis device according to the invention, and a method for determining the preferred operating current for electrodialysis systems according to this invention.

Abstract: A new method for improving the efficiency of electrodialysis (ED) cells and stacks, in particular those used in chemical synthesis. The process entails adding a buffer solution to the stack for subsequent depletion in the stack during electrolysis. The buffer solution is regenerated continuously after depletion. This buffer process serves to control the hydrogen ion or hydroxide ion concentration so as to protect the active sites of electrodialysis membranes. The process enables electrodialysis processing options for products that are sensitive to pH changes.

Abstract: A method and apparatus for producing purified water. An electrochemical system can be configured to pass product water through depletion compartments as well as a cathode compartment. An electrochemical apparatus may also be configured to pass concentrate through both concentrating compartments and an anode compartment.

Abstract: A water treatment system provides treated or softened water to a point of use by removing a portion of any hardness-causing species contained in water from a point-of-entry coming from a water source, such as municipal water, well water, brackish water and water containing foulants. The water treatment system typically treats the water containing at least some undesirable species before delivering the treated water to a point of use. The water treatment system has a controller for adjusting or regulating at least one operating parameter of the treatment system or a component of the water treatment system to optimize the operation and performance of the system or components of the system. A flow regulator regulates a waste stream flow to drain and can be operated to recirculate fluid through electrode or concentrating compartments of an electrochemical device and can opened and closed intermittently according to a predetermined schedule or based on an operating parameter of the water treatment system.

Abstract: The invention includes novel anion exchange membranes formed by in situ polymerization of at least one monomer, polymer or copolymer on a woven support membrane and their methods of formation. The woven support membrane is preferably a woven PVC membrane. The invention also includes novel cation exchange membranes with or without woven support membranes and their methods of formation. The invention encompasses a process for using the membranes in electrodialysis of ionic solutions and in particular industrial effluents or brackish water or seawater. The electrodialysis process need not include a step to remove excess ions prior to electrodialysis and produces less waste by-product and/or by-products which can be recycled.

Abstract: An electrically and ionically conductive porous material including a thermoplastic binder and one or more of anion exchange moieties or cation exchange moieties or mixtures thereof and/or one or more of a protein capture resin and an electrically conductive material. The thermoplastic binder immobilizes the moieties with respect to each other but does not substantially coat the moieties and forms the electrically conductive porous material. A wafer of the material and a method of making the material and wafer are disclosed.

Abstract: A method of water purification including the steps of passing source water through at least one reverse osmosis unit to produce a product water and reject water, directing the product water from a reverse osmosis unit into the dilution stream of a continuous electrodeionization unit, directing the reject water from the first pass reverse osmosis unit through a softening unit to produce softening unit output water with fewer hardness elements than the reject water from the first pass reverse osmosis unit, directing the softening unit output water into a concentrate stream of the continuous electrodeionization unit, and wherein the continuous electrodeionization unit further purifies the water from the dilution stream to produce purified water.

Abstract: An electrodeionization apparatus and method for purifying a fluid. A fluid, such as water, can be purified by removing weakly ionizable species from the fluid. Weakly ionizable species may be dissociated at different pH levels to facilitate removal from the fluid in an electrodeionization device.

Abstract: A method for producing deionized water by an electro-regenerating deionization method, which comprises employing a deionized water producing apparatus comprising an electrodialyzer, and ion exchangers being accommodated in the demineralizing compartments, supplying water to be treated in the demineralizing compartments and supplying a concentrated water to the concentrating compartments, wherein the concentrated water at the outlet of the concentrating compartments has a S value of 7 or more as defined by the following formula (1) and a pH of 2.5 or more: S value=(&ggr;−420000×A)/(B×(1−(A/0.004))3)  Formula(1), wherein &ggr; is electro-conductivity(&mgr;S/cm), A is hydrogen ion concentration (mol/l), and B is magnesium ion concentration (ppb).

Abstract: Bipolar membrane electrodialysis methods for salt splitting polyvalent metal salts, where the metal cation can form substantially insoluble precipitates in the presence of hydroxyl ions can now be used in recovering acid and base values from a salt streams without precipitates fouling cell operation and causing shutdown. The introduction of an acid to the chamber where metal hydroxides would form inhibits their development or neutralizes formed solids, allowing salt splitting to continue. Salt splitting methods of the invention performed with a three compartment bipolar electrodialysis cell are useful in producing concentrated and purified acid forms, such as 2-keto-L-gluconic acid, H(KLG), a key intermediate in the production of ascorbic acid.

Abstract: An electrodialysis apparatus includes a stack of alternating cation and anion semi-permeable, ion-selective membranes disposed between a positive DC potential anode electrode and a negative DC potential cathode electrode. The cation and anion selective membranes can be selective for monovalent or multivalent ions and form compartments therebetween through alternate compartments of which flow concentrate and diluate solutions such that the concentrate and diluate solutions are separated from each other by the ion selective membranes. Due to the potential maintained across each of the compartments and the cation and anion selective membranes separating the compartments, cations and anions as well as water will migrate from the diluate solution to the concentrate solution.

Abstract: An electrodialysis cell is operated in the presence of organic compounds that bind or chelate with the multivalent metals to form metal-chelate buffers. Among other things, this binding or chelating reduces power consumption, produces a stable cell operation, and avoids a fouling of the membranes while significantly improving membrane life, reliability, and operating costs. When a chelating agent is added to a salt solution containing multivalent cations, the chelating agent strongly binds with the cations, forming large size complexes. An ion exchange membrane retains these complexes within the compartment of the electrodialysis cell containing the feed solution. The multivalent cations is greatly inhibited from being transported across the cation exchange membrane, thus reducing the fouling of the cation membranes. Concurrently, the precipitation of the metals in the base loop is substantially abated.

Abstract: An apparatus and process produces salts by an electrodialysis operation. The basic electrodialysis apparatus is a cell having a number of compartments separated by membranes. A DC source is connected to drive a current through a feed stream passing through the cell which splits the salt stream into an acid and a base. The incoming feed may be nanofiltered to remove divalent metal. The base loop may be in communication with an ion exchange column packed with a material that removes multivalent cations. Depending upon the material being processed and the desired end result either or both the nanofiltration and the ion exchanged column may be used in the apparatus.

Abstract: First and second stages are used in electrodeionization to purify water including calcium and carbon dioxide and its hydrates. The diluting flow channels of the first stage include only anion exchange material or cation exchange material, and thus remove either carbon dioxide and its hydrates (and other anions) or calcium (and other cations) but not the other. The diluting flow channels of the second stage receive the diluting channel effluent from the first stage and include the other type of exchange resin (or a mixed resin) and remove the oppositely charged ions. The brine effluent from the concentrating flow channels in the first stage is isolated from the second stage, and calcium and total inorganic carbon tend to be removed in different stages so as to deter calcium carbonate precipitation in any of the concentrating flow channels.

Abstract: Water to be treated (feed water) flows through a series of desalination chambers filled with ion exchange resins on which impurity ions in the feed water are removed. Each desalination chamber consists of a cation-permeable membrane on one side with an anion-permeable membrane on the other side. The space between the two membranes is filled with the ion exchange resins and there are concentrate chambers on either side of the membranes. There is a cathode chamber or an anode chamber each located at either end of the assembly of alternating desalination and concentrate chambers. By circulating the concentrate water while adding acid to the concentrate water to maintain its acidity, scale deposition within the concentrating chambers and the electrode chamber is prevented so that deionizing capability of the entire assembly can be maintained.

Abstract: Two sub-desalination chambers d1 and d2 are defined by a cation exchange membrane 3 on one side, an anion exchange membrane 4 on the other side, and an intermediate ion exchange membrane 5 in between and are filled with ion exchange materials 8 to construct a desalination chamber D. Concentrating chambers 1 are provided via the cation exchange membrane 3 and the anion exchange membrane 4 on both sides of the desalination chamber D. The desalination chambers D and the concentrating chambers 1 are provided between an anode 7 and a cathode 6. While a voltage is applied between the anode 7 and the cathode 6, water is supplied to one of the two sub-desalination chambers d2 and then, water discharged from the first sub-desalination chamber d2 is supplied to a second sub-desalination chamber d1. Concentrate water is supplied to the concentrate chambers.

Abstract: An apparatus and process produces salts by an electrodialysis operation. The basic electrodialysis apparatus is a cell having a number of compartments separated by ion exchange membranes. A DC source is connected to drive a current through a feed stream passing through the cell which splits the salt stream into an acid and a base. The incoming feed may be nanofiltered to remove divalent metal. The base loop may be in communication with an ion exchange column packed with a material that removes multivalent cations. Monovalent selctive cation membranes may be used to effect preferential treatment of the monovalent cations to the base loop. Depending upon the material being processed and the desired end result either or both the nanofiltration and the ion exchanged column may be used in the apparatus.

Abstract: First and second stages are used in electrodeionization to purify water including calcium and carbon dioxide and its hydrates. The diluting flow channels of the first stage include only anion exchange material or cation exchange material, and thus remove either carbon dioxide and its hydrates (and other anions) or calcium (and other cations) but not the other. The diluting flow channels of the second stage receive the diluting channel effluent from the first stage and include the other type of exchange resin (or a mixed resin) and remove the oppositely charged ions. The brine effluent from the concentrating flow channels in the first stage is isolated from the second stage, and calcium and total inorganic carbon tend to be removed in different stages so as to deter calcium carbonate precipitation in any of the concentrating flow channels.

Abstract: A method and apparatus is provided for inhibiting scaling in an electrodeionization system and, more particularly, for increasing tolerance to hardness in the feed water to an electrodeionization unit by inhibiting precipitation of scale-forming metallic cations contained in the feed water and thereby increasing efficiencies of the electrodeionization system. Water to be purified is passed through an electrodeionization unit in which the flow in the diluting compartment is countercurrent to the flow in the concentrating compartment. This is to impede the migration of scale-forming metallic cations from the diluting compartment, through the cation exchange membrane, into the concentrating compartment and towards the concentrating compartment side of the anion exchange membrane, thereby preventing scale formation on the anion exchange membrane.

Abstract: A method and apparatus for inhibiting scaling in an electrodeionization system or in a combined reverse osmosis/electrodeionization system for water treatment and, more particularly, for increasing tolerance to hardness in the feed water to an electrodeionization unit to inhibit precipitation of metal cations contained in the feed water and for increasing efficiency of the electrodeionization system. Water to be purified is passed through a electrodeionization unit in which a concentrate stream recycling through concentrating compartments and anode and cathode compartments contains effective amounts of an antiscalant to inhibit precipitation of scale. One or more preliminary reverse osmosis units in series with the electrodeionization unit preferably receives a portion of the antiscalants in the concentrate stream. The antiscalant in the water fed to the reverse osmosis unit can be supplemented and adjusted.

Abstract: A process of demineralizing a liquid containing organic matter and inorganic salts in solution, in which the treatment of the liquid comprises the following steps:the liquid is percolated over a strong cationic ion exchange resin for monovalent ions;both a batch of liquid from the preceding step and a brine for receiving ions from that liquid are caused to circulate in loops through at least one "two-compartment" electrodialyzer comprising a plurality of anionic membranes interposed between a plurality of cationic membranes; andthe brine whose salt concentration lies in the range 90 grams per liter (g/l) to 110 g/l is used to regenerate the ion exchange resin.

Abstract: A method for preventing scale from precipitating and an apparatus for producing deionized water are disclosed. The acidic water produced by electrolysis in the electrolysis unit (30) is introduced into a concentrating compartment (19) in the continuous deionization unit (10). The pH of the concentrated water in the concentrating compartment decreases, thereby preventing scale from precipitating.

Abstract: A method is provided for removal of ferrous ions from a tin-plating electrolyte containing stannous ions in a multi-compartmented electrochemical cell equipped to convert the ferrous and stannous ions to insoluble hydroxides. The hydroxides, in an essentially air-oxygen free environment, are separated by selectively dissolving the ferrous hydroxide in an acidic solution and the undissolved stannous hydroxide in the tin plating electrolyte.

Abstract: In an electrolyzer provided according to this invention, the polarity of electrodes is periodically inverted at very short intervals. This has the effect of allowing gases to be generated uniformly all over the surface of each electrode in the form of extremely small bubbles instead of being formed in specific positions in the form of large bubbles as is the case with a conventional electrolyzer in which a direct current is allowed to flow without changing the flow direction. Thus the surfaces of electrodes are prevented from being covered with bubbles, and the flow of liquids along the surfaces of electrodes is not disturbed by the bubbles any more.

Abstract: Electrodeionization apparatus having a novel polarity reversal protocol designed to provide continuous, high-quality product fluid is described. The protocol involves substitution of a recirculating fluid stream established in an ion-concentrating compartment by a fluid stream having a lower ionic concentration, while maintaining fluid flow through an adjacent ion-depleting compartment. A method and protocol for modifying the ionic makeup of compartment ion exchange material and fluids are also provided. A flow reversal protocol is also provided, during which high-quality fluid product is recovered from the inventive apparatus. The polarity reversal protocol and flow reversal protocol may each be effected separately, or the flow reversal may be introduced into the sequence of the polarity reversal protocol.

Abstract: A process for treating effluent from a flue-gas desulfurization system wherein the resulting gypsum is removed, comprises filtering the gypsum and fly ash free effluent by a filter, transferring the filtrate to an electrodialyzer wherein cation-exchange membranes and univalent anion-exchange membranes are alternately set up, concentrating chlorine ions in the solution therein by dialysis, further concentrating the solution by evaporation in an evaporator, kneading the concentrated solution with cement or a mixture of cement and coal ash to a solid matter with no harm, and thereafter abandoning for landfill; and an apparatus for treating effluent from a flue-gas desulfurization system, comprising a filter for filtering the effluent to a turbidity low enough for treatment by an electrodialyzer wherein the effluent is to be separated into concentrated and dilute solutions, the electrodialyzer equipped with an alternate arrangement of cation- and anion-exchange membranes, with concentration and dilution compartme

Abstract: In an electrodeionization apparatus having a cathode compartment and an anode compartment for removing ions from a liquid under the influence of a voltage, the cathode compartment includes electron conductive particles such as metal particles and/or carbon particles.

Abstract: In order to reduce releasing of neutral salts comprising monovalent ions contained in industrial waste effluent to the environment, the waste effluent to be treated is supplied into a prepositive electrodialysis cell comprising ion exchange membranes which transfer monovalent ions selectively for concentrating the salts, concentrated stream is supplied into an electrolytic dialysis cell for separating and recovering acids and bases, subsequently diluted stream is circulated as supplying stream to the prepositive electrodialysis cell, the diluted stream in said prepositive electrodialysis cell is subsequently supplied to and desalted by one or plural electrodialysis cells combined in series, the diluted stream after the desalination is released to the environment, and the concentrated stream is merged to the supplying stream to the prepositive electrodialysis cell.

Abstract: A process using an electrodialysis system employing cation-selective membranes and anion-selective membranes, particularly monovalent anion-selective membranes is used to separate kraft pulping liquors into two streams; one that is rich in sulphides (to be used in the initial stage of pulping), and another that is poor in sulphides (to be used in the final stage of pulping). By separating pulping liquors in this way, the sulphur balance in the kraft process can be maintained while obtaining the benefits of modified pulping. The same electrodialytic system can be used to separate green and polysulphide liquors into sulphide-rich and sulphide-poor components.