Abstract: A method for recovering amino acids, which comprises supplying a mixed solution containing inorganic acid salts, amino acids and non-electrolytes such as saccharides to a first-step resin layer comprising an Na type or K type strongly acidic ion exchange resin; separating an effluent into at least a first fraction containing coloring matters, acidic amino acids and ashes, a second fraction containing neutral amino acids and saccharides, and a third fraction containing betaines; supplying the second fraction to a second-step resin layer comprising at least one resin selected from the group consisting of NH4 type, Ca type and Mg type strongly acidic ion exchange resins, and optionally further supplying it to a third-step resin layer comprising an Mg type or Ca type strongly acidic ion exchange resin different from the resin of the second-step resin layer, thereby recovering various kinds of amino acids contained in an effluent.

Abstract: An adsorbent or bradykinin comprising styrene-divinylbenzene copolymer having sulfonic acid groups and a method for adsorbing and removing bradykinin comprising contacting the adsorbent with a fluid containing bradykinin are provided. An adsorber for adsorbing bradykinin in which the adsorbent is charged in a vessel having an inlet and an outlet for a fluid is also provided.

Abstract: The present invention relates to methods for depleting endotoxin from biological solutions by exposure of solutions containing endotoxin to an immobilized metal affinity chromatography matrix composed of a metal ion such as iron (III) bounds to a resin, wherein the metal is capable of selectively binding endotoxin in the solution. These methods are useful for purifying, for example, biological products prepared using bacterial cells, or products in which bacterial contamination is problematic. In another embodiment, endotoxin in circulation in a body can be removed by exposing the blood to the aforementioned matrix, whereby endotoxin is removed before the blood is returned to the body.

Abstract: The present invention has its objects to provide an adsorbent capable of efficiently adsorbing and removing LDL and VLDL from various lipoprotein-containing solutions, as well as a lipoprotein adsorber in which the adsorbent is used. This invention is related to a lipoprotein adsorbent which comprises a water-insoluble carrier having, on at least one part of the surface of the carrier, at least one group (other than p-nitrobenzoic acid) selected from the group consisting of groups represented by the general formula, and groups represented by the general formula.

Abstract: A process for the removal of ethers and/or PAH's from water, such as contaminated groundwater, is provided that proceeds by initially separating off solid constituents and then adsorbing ethers and polycyclic aromatic hydrocarbons to an adsorber resin, then, as needed, desorbing the adsorbed compounds with steam and regenerating the adsorber resin with an acid, to provide purification of highly polluted groundwater to such a substantial extent that the groundwater can be added to flowing surface waters without problem, and, if desired, used as cooling water or, after further biological purification, as drinking water.

Abstract: A procedure for reducing the patulin content in a fruit juice which includes presenting the juice to a resin material having in abundance micropores of less than 20 Å minimum pore width and at least a pore surface capable of retaining patulin by the forces of chemisorption. Preferably the resin has weak base functionality and is substantially devoid of mesopores and macropores. The resin preferably has a surface area of greater than 900 m2/g (BET) and the resin has been hypercross-linked whilst in the swollen state. Regeneration involves the conversion of the resin held patulin to a more easily flushed out derivative using ammonia or a volatile base, preferably generated in situ from a high pH solution.

Abstract: Anion-exchange compositions are provided comprising anion-exchange functional groups comprising at least a first and a second nitrogen group, wherein the first nitrogen group is a quaternary amine and the second nitrogen group is selected from the group consisting of primary, secondary, tertiary or quaternary amines. Methods of making and using the compositions are also provided.

Abstract: The present invention relates to a process for preparing mono-disperse adsorber resin gels by polymerizing monomer droplets to give monodisperse polymers, followed by haloalkylating and crosslinking the resultant polymers, and also relates to the use of these resins.

Abstract: The present invention relates to a process to remove quaternary ammonium salt (QS), from brine solution. The process uses an adsorbent selected from the group consisting of activated carbon and pyrolyzed sulfonated polystyrene divinylbenzene resin, or mixtures thereof which aids in removing the quaternary ammonium salt (QS). The process can be generally carried out at a temperature ranging from about −10° C. to about 90° C., at a pH ranging from about 1 to about 13.

Abstract: A process for producing or separating trehalose and/or sugar alcohols from hydrogenated saccharide mixtures containing trehalose and sugar alcohols selected from the group consisting of sorbitol, maltitol, and maltotriitol, which comprises the steps of subjecting hydrogenated saccharide mixtures containing trehalose and the sugar alcohols to column chromatography using strong-acid cation exchange resins, and successively eluting and collecting a trehalose-rich fraction and a sugar alcohol-rich fraction in this order.

Abstract: Wastewaters and circulation waters in papermaking, in deinking and in pulp bleaching are treated by adsorption of water-soluble anionic compounds and compounds dispersed in water from the wastewaters and circulation waters over finely divided adsorbents which consist of insoluble, only slightly swellable polymers which contain polymerized vinylamine units, and these polymers are used as adsorbents for treating water circulations in papermaking and for treating paper machine wastewaters and wastewaters from the deinking process and from pulp bleaching.

Abstract: A method for removing hydrocarbon products from water surfaces, which entails contacting the hydrocarbon products with a crystalline polypropylene, which when observed under a microscope of 2500 magnetization, exhibits a spongy surface having relatively homogeneous intercommunicating pores, with dimensions of between about 3 &mgr;m and 20 &mgr;m in diameter.

Abstract: A method and apparatus for removing organic contaminants from an aqueous phase in which the contaminant is solubilized. In the method the aqueous phase is passed through a fluid-pervious filtration media which has been infused with an absorbtion composition comprising a homogeneous thermal reaction product of an oil component selected from the group consisting of glycerides, fatty acids, alkenes, and alkynes, and a methacrylate or acrylate polymer component. The contaminant is thereby immobilized at said media, and the purified filtrate having passed through the filtration media is collected as the product.

Abstract: A plurality of water- and oil-porous sacks are partially filled with a number of generally toroidal bodies of a polymer material that entraps oil and including mesh fragments scattered throughout the bodies. Each sack is sewn with a perimeter stiffening ring, to retain a flat profile, and has a netting that closes to help inhibit outflow of the oil when the sack is retrieved. When deployed from ship or by air onto a spill, the sacks spread into a pancake shape and the polymer matter forms a single layer that retains the oil. The inventive sacks will float indefinitely without releasing the oil or allowing it to emulsify, so the oil can remain in place until collection efforts are feasible. The sacks can be burned in situ, or standard fishing boats or specialized collection boats can be used to retrieve the sacks, and the collected material can be burned to capture the energy content of the oil or processed to separate the oil from the polymer.

Abstract: Compounds which possess a complementary structure to a desired molecule, such as a biomolecule, in particular polymeric or oligomeric compounds, which are useful as in vivo or in vitro diagnostic and therapeutic agents are provided. Also, various methods for producing such compounds are provided. These polymeric or oligomeric compounds are useful in particular as antimicrobial agents, receptor, hormone or enzyme agonists and antagonists.

Abstract: The hydrophilic organic contaminants and hydrogen peroxide present in semiconductor fabrication reclaims are removed by means of adsorption of a pyrolysate of a macroreticular sulphonated vinyl-aromatic polymer having a carbon content of at least 85% by weight and a carbon/hydrogen atomic ratio of from 1.5:1 to 20:1. In spite of their hydrophobic surface, the pyrolysates have a comparatively high adsorptivity for these contaminants and provide for distinctively higher removal rates than customary activated carbons.

Abstract: Conventional regenerative adsorptive methods for the purification of waters of organic constituents are limited in their application, when owing to a low content of organic water constituents the loading of the adsorbers is so low that the condensed water vapor desorbate no longer has a tendency to form two phases, or when the organic components are readily water-soluble and thus, following desorption with water vapor, can be separated only with difficulty out of the condensed desorbate. The process of the invention improves the tendency toward phase separation by cycling back the aqueous phase of the desorbate onto a loaded adsorber prior to its desorption in order to increase the loading and reduce, through additional supply of external heat, the required amount of water vapor for desorption. The present process is particularly useful for purification of industrial process waters or ground water.

Abstract: The invention is concerned with a process for the selective separation of morpholine from an aqueous solution containing morpholine, N-methylmorpholine and N-methylmorpholine-N-oxide, characterized by the following steps:(A) passing said aqueous solution over a cation exchanger capable of adsorbing morpholine in such an amount until it cannot be charged substantially with morpholine any more and an eluate substantially free from morpholine but containing N-methyhnorpholine and N-methylmorpholine-N-oxide is obtained, and(B) regenerating the cation exchanger charged with morpholine and reusing it in step (A).

Abstract: There are electrically conductive, electroactive functionalized conjugated polymers having formula (I): ##STR1## These electrically conducive, electroactive conjugated polymers may be covalently bonded to a first biological molecule or antiligand. Polymers bonded to a first biological molecule or antiligand may be used to form an electrode and may be used to assay for, detect and/or extract a second biological molecule or ligand.

Abstract: The present invention relates to compositions for use in medicine, e.g. as infusion or surgical rinse solutions, and to processes for their preparation. The compositions of the invention comprise an aqueous solution of physiologically inert PVP having a weight average molecular weight in the range of from 3,000 to 14,000 daltons.

Abstract: A process for lowering the amount of epichlorohydrin and related hydrolysis compounds contained in paper strength enhancing resins by treating an aqueous solution of the resin with an adsorbent.

Abstract: A method for reducing the toxicity, bioaccumulation and concentration of chemicals in surface water sediments and water using a retrievable organic carbon scavenger is disclosed. The scavenger is comprised of a porous polymeric material, optionally containing an adsorbent such as activated carbon, and may exist in the form of beads, sheets, fibers, netting or other similar forms. The material is placed in contact with the sediment, toxic compounds are absorbed from the sediment, and may be retrieved for regeneration or disposal.

Abstract: The present invention relates to a process for preparing a radiation-sensitive composition, comprising the steps of (1) passing a solution of a crude polymer comprising a mixture of polymer chains having different molecular weights through a porous polymeric media having a predetermined molecular weight cut-off (MWCO) value, thereby separating the crude polymeric mixture into a first fraction comprising polymer chains having molecular weights above the MWCO value and a second fraction comprising polymer chains having molecular weights below the MWCO value; and (2) adding at least one fraction produced in the first step to at least one radiation-sensitive compound and at least one solvent to produce a radiation-sensitive composition.

Abstract: A method for the removal of organic compounds from columns of air or water. The method utilizes a solidifying organic polymer-based filtration media and activated carbon placed in separate containers and arranged in an in-line, two phase process to extract organic compounds and metals from feed streams containing emulsified or suspended concentrations of organic contaminants by absorbing and solidifying the organics into an easily retrievable, disposable mass. The treated feed streams exit the process containing acceptable limits of the organic compounds and metals within the fluid columns to permit their free release into the environment.

Abstract: A method and apparatus for collection and containment of hydrocarbons that may be spilled or leaked by equipment utilizing an internal combustion engine, transmission or fuel tank prevents pollution of the environment. Hydrocarbons accumulated in a spill collection apparatus are directed to a spill containment device where they are absorbed and solidified into a rubber-like mass. Solidification of hydrocarbons and retaining them within a hydrocarbon impermeable housing prevents them from contaminating the surface below the equipment and facilitates their handling for disposal.

Abstract: There is provided water insoluble cross-linked polycarboxylic acid having at least two strands in a strand skeleton of the formula: ##STR1## wherein one carbonyl group of at least one maleoyl moiety thereof in each strand is covalently linked to a--HN.[(H).sub.p (CH).sub.2.(OH).sub.m ].NH-- moietyto provide the presence therein of at least one cross linked moiety of the formula: ##STR2## wherein R is hydrogen or lower alkylene or lower alkoxy of 1-4 carbon atoms, or phenyl, x and y are integers, z is an integer of 1-6, p is 0 or an integer up to z-1, m is 0 or an integer up to z, and w is an integer from 2-12. There is disclosed a method of making such polycarboxylic acid as well as methods of utilizing same to remove proteins from aqueous media containing same to provide a matrix. Methods are disclosed for recovering proteins from said matrix without denaturing them and methods for recovering the polycarboxylic acid from said matrix.

Abstract: Dendritic polymer based networks consisting of well-defined hydrophilic and oleophilic (i.e., hydrophobic) domains, are capable of performing as nanoscopic sponges for electrophilic guest moieties such as (i) inorganic and organic cations; (ii) charged or polarized molecules containing electrophilic constituent atoms or atomic groups; and (iii) other electrophilic organic, inorganic, or organometallic species. As a result of such performance, the networks yield novel nanoscopic organo-inorganic composites which contain organosilicon units as an integral part of their covalently bonded matrix.

Abstract: A process for the removal of endotoxin from a biological product such as proteins for therapeutic use, blood plasma fractions, and albumin solutions that contains endotoxins, which comprises contacting said biological product with a cross-linked hydrophilic matrix comprising a copolymer of allyl dextran and N,N'-methylene bisacrylamide under conditions effective to bind endotoxins in said biological product to said matrix, wherein the total amount of endotoxin in said biological product does not exceed the absorptive capacity of said cross-linked hydrophilic matrix, and recovering purified biological product from which endotoxin has been removed as a result of said binding.

Abstract: A method and apparatus for removal of contaminants from fluid columns utilizes a solidifying polymer-based filtration media to extract pollutants, such as organic compounds and metals. Dissolved, emulsified or suspended contaminants are absorbed and solidified into an easily retrievable mass and retained within a replaceable filter container. Solidified contaminants may not leach when exposed to pressure limits currently used to determine landfill acceptability, may be incinerated as fuel for their BTU content or used as a component in the production of asphalt, roofing material or other tar-like compounds. Treated fluid columns exit the process containing acceptable levels of contaminants to permit free release into the environment.

Abstract: The invention aims to provide an apparatus for purifying water containing organic halides therein improved so as to substantially achieve perfect removal of organic halides from water which has conventionally been considered to be impossible. The object set forth above is achieved, according to the invention, by an apparatus for purifying water containing organic halides therein characterized in that particles, fibers, nonwoven fabric, porous body or sintered body containing hydroxycarboxylic acid or polymer thereof having a chemical structure expressed by general formula: ##STR1## where R1-R6 are identical or different and represent hydrogen atom, hydroxyl-, carboxyl-, amino-, cyano- or alkyl-group having 1-5 carbons, p represents a natural number 1-10, and q and r represent an integer 0-10) as a main ingredient is used as organic halide adsorbent; and a residual concentration of organic halides in water can be decreased to the order of ppb.

Abstract: The invention provides a process for the recovery of erythorbic acid from an aqueous feed solution containing values of erythorbic acid at a concentration of less than 0.7 mol/kg, comprising adsorbing a major portion of said erythorbic acid with a solid phase adsorbent resin selected from resins carrying a pyridine function and resins of similar or weaker basicity; separating said erythorbic acid-containing resin from residual aqueous solution, and subjecting said erythorbic acid-containing resin to a desorbing operation with a neutral solvent at a temperature of at least 20.degree. C. higher than the temperature at which said adsorption is carried out, whereby there is obtained a solution of erythorbic acid in solvent in which the concentration of erythorbic acid is at least equal to its concentration in said aqueous feed solution.

Abstract: A method of recovering an oil-based liquid from a body of liquid including a first layer of the oil-based liquid and a second layer of a second liquid having an interface with the first layer. The oil-based liquid being denser than the second liquid and the interface having a variable level in the body. The method includes the steps of suspending a length of oil-based liquid absorbent material from a support above the body, extending the absorbent material down a vertical distance from the support through the second layer into the first layer for absorbing oil-based liquid from the first layer, conveying the absorbent material along a path through the first layer, absorbing the oil-based liquid from the first layer with the absorbent material, and maintaining the path of the absorbent material in the first layer by varying the vertical distance in response to a variation in the level of the interface.

Abstract: A method is disclosed for isolating plasmid DNA, having the steps of: suspending hydroxyapatite particles in a buffer solution having a pH of about 6 to about 9, about 1 to about 100 mM of a water-soluble calcium salt and about 1 to about 100 mM of tris(hydroxymethyl) aminomethane; adding a solution containing RNA and plasmid DNA, obtained upon bacteriolysis, to the hydroxyapatite particles-containing suspension, thereby adsorbing the RNA onto the hydroxyapatite particles in the suspension; and recovering the plasmid DNA from a supernatant of the suspension. The isolation method enables effective separation of the purified plasmid DNA from a solution containing RNA and plasmid DNA in a simplified process, without the use for any special separation device.

Abstract: A method of removing hydrocarbons, such as polynuclear aromatic compounds, like benzo(a)pyrene, from liquid smoke and flavoring compositions by contacting said compositions with a nonionic residue. The method reduces the hydrocarbon concentration by about at least about 80% by weight, and reduces the benzo(a)-pyrene content to about 1 part per billion or less, without adversely affecting the phenolic content of the liquid smoke and flavoring composition.

Abstract: A method for the removal of organic compounds from columns of air or water. The method utilizes a solidifying organic polymer-based filtration media and activated carbon placed in separate containers and arranged in an in-line, two phase process to extract organic compounds and metals from feed streams containing emulsified or suspended concentrations of organic contaminants by absorbing and solidifying the organics into an easily retrievable, disposable mass. The treated feed streams exit the process containing acceptable limits of the organic compounds and metals within the fluid columns to permit their free release into the environment.

Abstract: An insert for a storm drain or sanitary sewer inlet such as are found in factory or warehouse floors, parking lots and car washes in which the insert holds one or more bags of filter media. The bags have a very open structure such as coarse weave cotton permitting water entering the drain to pass through each bag and the filter media inside the bag. The entire bag may be conveniently withdrawn from the insert and replaced as the filter media becomes saturated. Preferably, a first bag contains an absorbant cellulose particulate media which absorbs oils and greases and post non-volatile hydrocarbons and a second bag contains specially textured activated carbon which absorbs organically bound heavy metals and volatile hydrocarbons as well other VOCs (volatile organic compounds). Various types of filter media and configurations of these media also allows for the removal of dissolved heavy metals, and even the removal of pathogenic microbes.

Abstract: An adsorbent for removing ketoamine-containing protein, which comprises carrying a compound having a terminal functional group of the formula: ##STR1## wherein each of R.sup.1 and R.sup.2 is an organic group and X is 0 or 1, on a porous water-insoluble carrier, a process for removing ketoamine-containing protein by employing the above adsorbent, a process for preventing or treating for diabetic complication by removing ketoamine-containing protein with the above adsorbent and an adsorber for removing ketoamine-containing protein.

Abstract: Water recovered from the polymerization of vinyl monomers can be treated to remove or deactivate chain transfer agents present in the water allowing resuse in polymerization processes. The water recovered from a vinyl polymerization reaction is contacted with a cation exchange resin in the hydrogen form prior to recycle, or may be acidified and then contacted with an anion exchange resin in the hydroxide form.

Abstract: A method for the use of a porous, preferably dimensionally stable, particulate material in a packed filter bed for separating a disperse liquid phase from a gas and/or separating a disperse liquid phase from a liquid, with the average size of the particles being in the range of from 0.1 to 10 mm and the internal surface area of the material being such that, after it has been filled with the disperse liquid phase to be separated and placed, as a packed bed, at a distance of from R to r from the center in a centrifuge rotating at an angular velocity w, for which it holds that0<w.sup.2 (R.sup.2 -r.sup.2).ltoreq.20 (rad/s).sup.2 m.sup.2,wherein w stands for the angular velocity (in rad/s) and R and r represent the largest and the smallest radius (in m), respectively, of the material in the centrifuge, at least 1% of the liquid will have been separated after 5 minutes, while at least 10% of the liquid will have been separated after 60 minutes is disclosed.

Abstract: A process for capture, degradation, and destruction of a sulfur bearing compound that satisfies the needs for a treatment process that may be used in cartridge, pipeline, and batch, that can handle a large variety of sulfur bearing environmental pollutants, is faster than other methods, and that does not leave dangerous degradation product fractions and residuals in wastewater from the treatment process itself. The present invention is further directed towards a treatment process that is capable of using a safe, dry storable cartridge with small amounts of dry storable mixed resins in a small cartridge, that can fit into a "point of use" pipeline from a contaminated well or point of contaminated "run-off". Dangerous degradation product fractions and residuals in wastewater, are minimized, in order to minimize residual environmental impacts from the treatment process itself. Sulfur bearing compounds are mixed with metals insoluble with the sulfur bearing compounds, reducing agents, and bases.

Abstract: An adsorption process uses a non-ion-exchangeable adsorbent polymeric resin of a monoethylenically unsaturated monomer such as styrene and a polyvinylidene monomer such as divinylbenzene for the adsorption of organic bases, such amines, amine salts and guanidinium salts, from high ionic strength aqueous solutions. Desorption may be employed for the recovery of said organic bases, and said adsorbent resin may be regenerated.

Abstract: A method and system for removing miscible organic compounds from contaminated water is disclosed. The system of the present invention comprises a polisher for filtering out trace amounts of suspended solids, a system of columns connected in series and containing an adsorbent to adsorb miscible organic compounds, a source of ozone, and a contact tower for contacting the contaminated water with the ozone such that the ozone decomposes the miscible organic compounds to produce water that is substantially free of miscible organic compounds. The present invention also comprises a method of rejuvenating the adsorbent in individual columns.

Abstract: Process and apparatus for separating aryl phosphates and esters and hydrolysates thereof from water in an aqueous mixture thereof. A superposed layer of the mixture is decanted from a lower layer of the phosphates, esters and hydrolysates. The superposed layer is filtered with a filter having a pore size of between 1 micron and 25 microns to remove globules and solid particles. The effluent is then subjected to demineralization with an anion exchange resin to remove most of the hydrolysates. Thereafter a sorber composed of an organic polymeric material such as polypropylene removes any remaining phosphates and esters down to less than 250 ppb.

Abstract: Polluted groundwater is purified by separating off solids and adsorbing dissolved organic compounds to an adsorber resin. The adsorbed organic compounds are desorbed using steam and the adsorber resin is regenerated using an acid and an oxygen-containing gas. The process makes it possible to separate aromatic and halogenated hydrocarbons off of heavily polluted groundwater to the extent that the groundwater can be added to flowing surface water without reservation. The purified water can, if appropriate, be used as cooling water, or after further biological purification, as drinking water.

Abstract: The invention relates to activated support materials which comprise epoxy-substituted poly(meth)acrylamides, characterized in that:a) the base support contains aliphatic hydroxyl groups,b) the covalently bonded polymers are bonded to the support via a terminal monomer unit,c) the polymers contain monomer units of the formula I,d) the monomer units are linearly linked, ##STR1## in which R.sup.1, R.sup.2 and R.sup.3 independently of one another are H or CH.sub.3,R.sup.4 is H or alkyl having 1-5 carbon atomsandn is an integer between 1 and 5 and to the use thereof.

Abstract: Simple and efficient methods for scavenging excess electrophiles from a reaction mixture are provided utilizing addition of water soluble nucleophiles or solid support bound nucleophiles. Resulting addition products are removed from reaction mixtures through convenient separation techniques.

Abstract: Amide-containing polymers characterized by the presence of piperazine amide and/or substituted piperazine amide in the polymer chain are used as adsorbents to remove polyphenolic compounds from liquids. The compositions are especially useful in combination with protein removal agents such as silica gel or tannin. The amide-containing polymer compositions (alone or in combination with protein removal agents) are especially useful in the stabilization and/or chillproofing of plant derived liquids or beverages such as beer, wine, fruit juice and vegetable juice.

Abstract: A particulate adsorbent is the crosslinked polymerization product of a brominated vinyl aromatic monomer and a crosslinking monomer and exhibits a density greater than or equal to about 1.01 grams per cubic centimeter and a surface area greater than or equal to about 10 square meters per gram.

Abstract: An apparatus and method for removing unwanted substances from media such as water and soil. Various industrial waste water streams can be treated simply and effectively to remove therefrom such unwanted substances as petroleum hydrocarbons, heavy metals, phenolics, salt, ethylene glycol, and strontium, and sea water can be similarly treated to remove salt as well as petroleum hydrocarbons therefrom. Waste water or sea water is contacted with zeolite in the presence of a surfactant, and optionally hydrophobic cellulose, to effect removal of the unwanted substances therefrom; and soil contaminated with petroleum hydrocarbons, salt or agricultural chemicals can be rejuvenated by mixing the soil with zeolite and a surfactant followed by washing. The apparatus and method provides simultaneous removal of a wide variety of unwanted substances from a feed stream passed therethrough, in contrast to prior art procedures effective to remove only one such substance per treatment.

Abstract: Large volumes of waste water stream containing oil, greases, sometimes ferric ions, and dissolved contaminant hydrocarbons such as BTEX are rapidly treated in two stages. Initially, the oils and greases are separated, then the dissolved contaminant hydrocarbons are removed by countercurrent adsorption on powdered resinous polymeric adsorbents in an exchange zone, preferably in the absence of ferric ions. The contaminant laden adsorbents are regenerated and continuously recycled to the exchange zone.