Abstract: Waste from a nuclear power plant, containing organic ion-exchange resin containing radioactive metals, is decomposed to form volatile substances by means of oxidation in an acid, aqueous liquid (8). Radioactive metal ions thus dissolved in the liquid, which are precipitable with hydroxide, are then caused to precipitate by the addition of a hydroxide (10) at a pH value of at least 9, and the metal compounds thus precipitated are separated from at least most of the liquid. Radioactive caesium and strontium ions in this liquid are removed therefrom. The liquid (24) separated from precipitated metal compounds and freed from caesium and strontium ions is released to a recipient, with the remaining substances still dissolved in it, and the precipitated metal compounds (11k, 11s) are solidified in a deposition container (22). The ion-exchange resin preferably consists at least partially of sulphonated ion-exchange resin and the hydroxide preferably of sodium hydroxide or some other alkali metal hydroxide.

Abstract: A method is disclosed for absorbing bases, acids, alcohols and radioactive liquids using phenol resin foamed plastic particles. The size of the particles should lie between about 0.3 and 3 mm. The particles are initially closed-celled, but have been powdered or fine flaked. They may be treated with an acid for absorbing a base, or with a base for absorbing an acid. A preferred use is in the form of packing material. The particles may be disposed in the form of powder or flakes in liquid-permeable padding. The padding may be composed of a plastic web, in particular a nylon web, or of a non-woven fabric. As packing material the phenol resin foamed plastic may be in the form of sheets, blocks, cubes, tablets, balls or fragments.

Abstract: A process for separately recovering uranium and hydrofluoric acid from a waste liquor containing uranium and fluorine comprises a neutralizing precipitation step wherein a magnesium compound is added to the waste liquor containing uranium and fluorine to form a precipitate and the thus formed precipitate is then separated; a distillation step wherein an aqueous solution of sulfuric acid is added to the precipitate separated in said neutralizing precipitation step to dissolve the precipitate and the thus formed solution is then distilled to recover hydrofluoric acid as a distillate; and a uranium recovery step wherein uranium is recovered from a residue produced by said distillation step.

Abstract: A method for a quantitative separation of scandium from thorium comprises adsorption of both metals on a cation exchange resin followed by selective elution of scandium with an acidic solution of a chelating agent followed by the elution of thorium by a six normal hydrochloric acid solution.

Abstract: A method for treating a radioactive metal-containing natural water or liquid such as a radioactive metal-containing wastewater stream, an oil containing one or more radioactive metals, or other nuclear metal-bearing liquid by contacting the radioactive heavy metal-containing liquid with a water-in-soluble carboxylated cellulose to separate the heavy metals from the liquid. The process has been found to be unexpectedly effective on radioactive wastewaters or any other liquid containing one or more radioactive heavy metal ions such as U, Ce, Sr, Ru, Ra, Np, Tc, as well as radioactive ions such as I.

Abstract: In operation of a boiling water-type, atomic power plant, rated operation is conducted while adjusting the pH of core water in the nuclear reactor to 7.0 to 8.5 by adding an alkali thereto, thereby controlling dissolution of radioactive corrosion products attached to fuel rods into the core water. An increase in the radioactive corrosion products in the core water and in the dose rate can be prevented.

Abstract: Process for preventing the extraction of technetium and/or rhenium, particularly during the extraction of uranium and/or plutonium by an organic solvent.This process permitting the extraction of a chemical element, such as uranium or plutonium present in an aqueous solution containing both said element, technetium and/or rhenium and zirconium and/or hafnium consists of contacting the aqueous solution with an organic solvent able to extract said element, wherein for preventing the extraction of the technetium and/or rhenium with said element, to the aqueous solution is added a zirconium and/or hafnium complexing agent in a quantity adequate for complexing all the zirconium and/or hafnium, said agent being soluble in the aqueous solution.

Abstract: Synthetic Crandallites of the general composition MeAl.sub.3 (PO.sub.4) (OH).sub.5.H.sub.2 O (Me=alkaline earth metal) are used for the separation of cations, especially alkaline earth metals, lanthanides and actinides, at a pH greater than 6 and temperature above 40.degree. C.

Abstract: A process is described involving the detoxification of waste water containing heavy metals which includes recovering the metals in salable form. The metals are removed from the waste water by contacting the water with an ion exchange resin bed contained in a portable canister until it is determined that the resin is saturated with metal. This determination is made by measuring the appearance of heavy metal salts in the effluent from the canister. Regeneration of the resin and recovery of the metal is accomplished in a location diverse to that where the metal is removed from the waste water by (a) back washing the resin with water into a backwashing receiver (b) forward washing the resin with water (c) forward washing the resin with a regenerating solution (d) collecting the regenerating solution in a plurality of fractions wherein the first fractions contain the majority of the metal recovered and (e) forward washing the resin with water to remove excess regenerating agent.

Abstract: The invention relates to a process for decontaminating and adjusting the pH of uraniferous solutions to render them compatible with the natural environment into which they may be discharged. This process is characterized in that the solutions to be treated having a natural pH from about 2.5 to about 6.5 and containing from about 1 to about 100 mg/l of uranium, are supplemented with an aluminum salt, such as sodium aluminate, in a sufficient amount for the final pH to be from about 5.5 to about 8.5 and for there to be precipitation, coagulation and adsorption of about 90% of the uranium initially contained in the solution and for the uranium content remaining in the final solution obtained to be equal to or less than about 1.8 mg/l.

Abstract: Disclosed is an inorganic polymeric cationic ion exchange matrix which is the condensation polymerized reaction product of components including an alkyl compound of an element that has a valence of at least three, water, and a dopant having groups including an ion exchangeable moiety and a replaceable hydrogen. The ion exchange matrix is preferably made by adding the water to the alkyl compound first followed by the addition of the dopant, followed by heating to dryness. The resulting product is a powder or granule that can be used as an ion exchange matrix by placing it in a column and passing a solution through it which contains metal ions that are exchanged with ions on the polymer.

Abstract: An initial aqueous pertechnetate solution which has a low electrolyte concentration compared with physiological saline is treated by passage through a bed of insoluble ion exchange material for adsorbing the pertechnetate. In a second step an ionic eluant having a smaller volume than the pertechnetate solution is passed through the bed to remove the pertechnetate to provide a relatively concentrated and pure eluate solution, the ion exchange material in the bed and the ionic eluant having respective properties for providing the eluate with a pH suitable for radiopharmaceutical purposes. The bed retains thereon radionuclidic impurities which may have been in the initial solution. The method can be valuable for treating the eluate from a portable technetium generator which is eluted with water and advantageously the insoluble material in the bed is zirconium oxide.

Abstract: A process for the enrichment and separation of oxides of heavy hydrogen isotopes from acid, aqueous solutions or other aqueous streams employs macrocyclic aminopolyether (APE) and organic cation exchange agents. The aqueous solution or the aqueous stream is mixed with at least one organic solvent which is miscible with water to form a liquid mixture. An organic acid cation exchange agent in the H-form is charged with a protonized APE to form a solid phase. The liquid mixture is brought into contact with the solid phase to bring about the enrichment of the heavy hydrogen isotope on the solid phase at a low temperature. The heavy hydrogen isotope from the solid phase is then released at a temperature that is higher by between 30.degree. K. and 150.degree. K. than the temperature at which the enrichment occurred.

Abstract: A method of decontaminating radionuclide-contaminated acid insoluble corrosion products from primary system surfaces in pressurized water reactors by oxidation and concurrent dissolution in an acidic decontamination solution of the corrosion products which have been made acid-soluble by the oxidation. The characterizing feature of the method is that the oxidation is carried out at relatively low temperatures with a water-based oxidation agent having a pH below 7 and containing cerium nitrate, chromic acid and ozone.

Abstract: A method for separating and purifying cations by ion exchange with regenerable porous glass. More specifically, the method is for decontaminating toxic waste streams such as a radioactive waste streams and concentrating the radioactive cations contained therein which comprises passage of the waste stream through an ion exchange medium of porous silicate glass or silica gel. In one embodiment, a liquid nuclear waste stream is passed through an ion exchange column containing porous silicate glass or silica gel having a plurality of .tbd.Si--O--Z groups wherein Z represents a non-radioactive cation (hydrogen, alkali metals, Group Ib metals and ammonium cations, and mixtures thereof) to displace the non-radioactive cations of the silicate glass or silica gel by the radioactive cations of the waste stream. Thereafter, the ion exchange medium is contacted with an aqueous solution of an acid to strip the radioactive cations therefrom and the stripped ion exchange medium is regenerated.

Abstract: A method of decontaminating mixtures of radioactively contaminated water and radioactively contaminated water-immiscible organic liquids to produce a decontaminated organic liquid which can be disposed of in a conventional manner.

Abstract: A novel ion exchange agent comprises a magnetically susceptible core or nucleus surrounded by a coating of plastic or resin ion exchange material, preferably a microreticular coating immediately surrounding the magnetically susceptible core and a macroreticular coating surrounding the microreticular coating and a novel method of preparing the same. A novel ion exchange process is disclosed, including applying a magnetic field to the body of the magnetically susceptible ion exchange agent to at least temporarily immobilize the ion exchange agent while passing liquids therethrough, particularly in the washing or other treatment of ground ores to recover mineral values therefrom in a resin-in-pulp process.

Abstract: A composition comprising a support such as a porous silicate glass or silica gel or charcoal having interconnected pores and containing heavy metal cations of mercury, thallium, silver, platinum, palladium, lead or copper capable of forming a stable complex with an anion bonded to the support. The preferred heavy metal cation is a mercury cation. The composition is especially useful for removing radioactive iodine from liquid and gaseous waste streams.

Abstract: A process for removing metal species from solution comprising passing the liquid over a composition comprising a support such as a porous silicate glass or silica gel or charcoal having interconnected pores and containing water soluble amine complexing agents absorbed on the support capable of forming a stable complex with the metal species. The preferred amine complexing agent is triethylenetetramine. The process is especially useful for removing radioactive cobalt from liquid waste streams.

Abstract: A process for removing heavy alkali metal cations from solution comprising passing a liquid over a composition including a support such as charcoal having interconnected pores containing a tetra-aryl boron moiety associated with an ion exchangeable cation absorbed on the support capable of forming a stable compound with a heavy alkali metal cation.

Abstract: High efficiency removal of technetium values from a nuclear waste stream is achieved by addition to the waste stream of a precipitant contributing tetraphenylphosphonium cation, such that a substantial portion of the technetium values are precipitated as an insoluble pertechnetate salt.

Abstract: A method of purifying cooling water used in nuclear reactors, which comprises contacting said cooling water with a hydrotalcite compound of the following formulaM.sub.1-x.sup.2+ M.sub.x.sup.3+ (OH).sub.2 A.sub.x/n.sup.n-. mH.sub.2 O (1)wherein M.sup.2+ represents a divalent metal cation, M.sup.3+ represents a trivalent metal cation, A.sup.n- represents an anion having a valence of n, and x and m satisfy the following expressions0<x<0.50.ltoreq.m<1or a calcined product thereof obtained by calcination at a temperature of up to about 900.degree. C.; and a purifying agent used therefor.

Abstract: Hydrazine is added to low-level radioactive waste, and the waste is contacted with an iron hydroxide-cation exchange resin so that its radioactive concentration may be lowered. The resin is a strongly acid cation exchange resin treated with ferric chloride and aqueous ammonia and containing a product of hydrolysis of ferric ions.

Abstract: The present invention relates to insoluble compositions, which are capable of removing metal (e.g. selectively) from solution (e.g. Fe.sup.3+ from a liquid nutrient medium so as to lower the Fe.sup.3+ content to less than 0.1 .mu.M); the insoluble compositions comprise: a suitable insoluble carrier and organic co-ordinating sites covalently fixed to the surface of said carrier, said co-ordinating sites being capable of chelating Fe.sup.3+, Th.sup.4+ and/or UO.sub.2.sup.2+.

Abstract: A method of processing radioactive liquid wastes containing radioactive ruthenium by passing said wastes through a column packed with an adsorbent comprising a mixture of activated carbon with zinc and palladium powders is herein disclosed.

Abstract: The invention is directed to a method vitrifying radioactive fission prods in liquid solution. The liquid solution is pumped in metered quantities from a feed container to a vitrifying oven. The offgas occurring during vitrification is scrubbed of entrained radioactive dust particles and the like by a scrubbing liquid in a scrubber. In order to obtain a simplified sequence of method steps for metering the liquid solution and for scrubbing the offgas, the radioactive fission product solution from the feed container itself is used as the scrubbing liquid. This fission product solution is taken from the feed container and conducted to the counterflow scrubber through which it is passed in a direction opposite to the flow of the offgas. The fission product solution used as a scrubbing liquid is returned to the feed container after passing through the counterflow scrubber.

Abstract: A process and apparatus for recovering uranium from a carbonate solution containing uranium ions whereby the carbonate solution containing uranium ions is brought in contact with a cation exchanger so that a uranium cation is removed from solution and adsorbed by the cation exchanger, and the uranium cation is then removed from the cation exchanger. The treated carbonate solution from which uranium ions hve been removed by cation exchange is then further processed by removing carbon dioxide from the treated carbonate solution to produce a decarbonated solution, and passing the decarbonated solution through a membrane process to remove some remaining impurities.

Abstract: Recovery of uranium from crude wet process phosphoric acid (WPA) by cation exchange using as cation exchanger a resin comprising active amino phosphonic or hydroxy phosphonic groups linked to a matrix. The operational steps comprise reduction of uranium in the WPA to the tetravalent state, contacting the WPA with the cation exchange resin to load the latter with tetravalent uranium, displacing Fe.sup.+2 from the resin, washing the resin with aqueous ammonia, eluting the resin with a carbonate-bicarbonate solution and precipitating uranium from the eluate.

Abstract: Process for removing diluent degradation products from a solvent extraction solution, which has been used to recover uranium and plutonium from spent nuclear fuel. A wash solution and the solvent extraction solution are combined. The wash solution contains (a) water and (b) up to about, and including, 50 volume percent of at least one-polar water-miscible organic solvent based on the total volume of the water and the highly-polar organic solvent. The wash solution also preferably contains at least one inorganic salt. The diluent degradation products dissolve in the highly-polar organic solvent and the organic solvent extraction solvent do not dissolve in the highly-polar organic solvent. The highly-polar organic solvent and the extraction solvent are separated.

Abstract: A process for the selective concentration of uranium from sea water through chemical accumulation onto a solid adsorption medium, which does not necessitate any H.sup.+ ions for regeneration, in particular onto titanium oxide hydrate and subsequent elution with a carbonate-containing eluent.

Abstract: The present invention relates to insoluble compositions, which are capable of removing metal (e.g. selectively) from solution (e.g. Fe.sup.3+ from a liquid nutrient medium so as to lower the Fe.sup.3+ content to less than 0.1 .mu.M); the insoluble compositions comprise: a suitable insoluble carrier and organic co-ordinating sites covalently fixed to the surface of said carrier, said co-ordinating sites being capable of chelating Fe.sup.3+, Th.sup.4+ and/or UO.sub.2.sup.2+.

Abstract: A radioactive waste is solidified by adding a nonionic high molecular flocculant to a slurry containing radioactivated crud to precipitate the crud, concentrate the thus treated slurry and then separating the crud from the slurry, drying said crud, mixing the dried crud with a frit of a low melting point and filling a steel can with the resulting mixture, heating the steel can to sinter and solidify the above described mixture, and sealing a surface of the solidified body in the steel can with a sealing material.

Abstract: Method for precipitating and removing soluble metal compounds from solutions of phosphoric acid. The method is useful in the disposal of metal-containing phosphoric acid waste from electrolytic operations, including such acid solutions contaminated with uranium compounds.

Abstract: This invention relates to the immobilization of toxic, e.g., radioactive materials, internally in a silicate glass or silica gel matrix for extremely long periods of time. Toxic materials, such as radioactive wastes containing radioactive anions, and in some cases cations, which may be in the form of liquids, or solids dissolved or dispersed in liquids or gases, are internally incorporated into a glass matrix, having hydrous organofunctionalsiloxy groups, e.g., hydrous aminoalkylsiloxy or carboxyorganosiloxy, bonded to silicon atoms of said glass and/or hydrous polyvalent metals bonded to silicon atoms of said glass through divalent oxygen linkages or otherwise immobilized therein, by a process which involves the ion exchange of said toxic, radioactive anions with hydroxyl groups attached to said organofunctionalsiloxy groups or with hydroxyl groups attached to the hydrous polyvalent metal.

Abstract: A process for treating a radioactive liquid waste is disclosed, in which a radioactive liquid waste containing uranium and .beta.-decay nuclides, daughter nuclides of uranium, is treated by combination of a flocculation method using water glass as pretreatment and a subsequent ion exchange method. An approximately total amount of the uranium and a part of the .beta.-decay nuclides, daughter nuclides of uranium, in the liquid waste are captured by an amorphous silica precipitate formed by addition of the water glass and a remaining part of the .beta.-decay nuclides, daughter nuclides of uranium, is captured thereafter by the ion exchange treatment. The thus captured radioactive materials are respectively eluted from the filtered out precipitate, a radioactive solid waste, and the ion exchanger by acid treatment to be recovered as an acidic solution. Thus, the radioactive materials in the liquid waste are recovered approximately completely, thereby making the radioactivities of a final drain remarkably reduced.

Abstract: A metal ion adsorbent free from release of oxine from activated charcoal even at a high temperature of more than 150.degree. C. is prepared by adsorbing oxine or its derivative onto activated charcoal, adsorbing a phenol onto activated charcoal, dipping the resulting activated carbon into an aqueous solution of aldehyde such as formaldehyde, methylolizing oxine or its derivative in the presence of an acid or an alkali as a reaction promoter, and binding the methylolized oxine derivative, and the phenol by copolymerization or oxine can be methylolized in advance and then adsorbed onto the activated charcoal in place of adsorption of oxine onto the activated carbon, followed by methylolization of the oxine on the surface of the activated charcoal.

Abstract: A method for separating an ionic substance from a liquid medium, which comprises including a metal ion, a metal oxide ion, a metal complex ion, ammonium compounds, etc. dissolved or dispersed in the liquid medium by using a fluorine containing compound of the following formula[{Rf-(A).sub.a -Y}(X).sub.b ].sub.n (Z).sub.ccontaining a fluoroalkyl group (Rf) having 3 to 20 carbon atoms and a group (Y) having affinity for the ionic substances. A composition for trapping ionic substances, comprising the aforesaid fluorine-containing compound as a main ingredient. The invention can be advantageously applied to the recovery of useful metals from ocean waters.

Abstract: A process is described for the recovery of uranium from ore wherein the ore is leached, the resulting leachate is passed over an anion exchange resin, and the resin is then eluted with an elution solution containing an anion capable of replacing the uranyl anion captured on the resin, followed by treatment with a sulfite-containing solution so that polythionates captured on the ion exchange resin are reacted to form essentially thiosulfate and trithionate. Preferably, the sulfite solution also contains other anions.

Abstract: This invention relates to the immobilization of toxic, e.g., radioactive, materials in a silicate glass or silica gel matrix for extremely long periods of time. Toxic materials, such as radioactive wastes containing radioactive cations, which may be in the form of liquids, or solids dissolved or dispersed in liquids or gases, are incorporated into a glass or silica gel matrix, having alkali metal, Group Ib metal and/or ammonium cations bonded to silicon atoms of said glass or silica gel through divalent oxygen linkages, by a process which involves the ion exchange of said toxic or radioactive cations with said alkali metal, Group Ib metal and/or ammonium cations to bind said toxic or radioactive cations to silicon atoms of said glass or silica gel through said silicon-bonded divalent oxygen linkages.

Abstract: What is disclosed are novel metal chelating agents which are bonded to inorganic substrates to immobilize them. An example of such a metal chelating agent is (CH.sub.3 O).sub.3 Si(CH.sub.2).sub.3 NH(CH.sub.2 CH.sub.2 NH).sub.2 (CH.sub.2).sub.3 Si(OCH.sub.3). An example of an inorganic substrate is a silica gel.

Abstract: Zeolite is contacted with an aqueous solution containing at least one of copper, nickel, cobalt, manganese and zinc salts, preferably copper and nickel salts, particularly preferably copper salt, in such a form as sulfate, nitrate, or chloride, thereby adsorbing the metal on the zeolite in its pores by ion exchange, then the zeolite is treated with a water-soluble ferrocyanide compound, for example, potassium ferrocyanide, thereby forming metal ferrocyanide on the zeolite in its pores. Then, the zeolite is subjected to ageing treatment, thereby producing a zeolite adsorbent impregnated with metal ferrocyanide in the pores of zeolite. The adsorbent can selectively recover cesium with a high percent cesium removal from a radioactive liquid waste containing at least radioactive cesium, for example, a radioactive liquid waste containing cesium and such coexisting ions as sodium, magnesium, calcium and carbonate ions at the same time at a high concentration.

Abstract: A method and apparatus for removing and disposing of contaminants from a contaminated fluid makes use of an expendable collection receptacle which is encapsulated in an inert protective matrix except for inlet and outlet ports and which is capable of removing and retaining contamination from the liquid when passed therethrough. The removed and retained contamination is subsequently encapsulated in a solid material within the receptacle by introducing a settable fluid material into the receptacle. The inlet and outlet ports are then encapsulated in a solid inert matrix so that the receptacle can be disposed of.

Abstract: Method of and apparatus for concentration of trace material from large voes of water. Carrier bodies having a lower density than that of water are introduced into a water layer, especially a natural sea current or stream; these carrier bodies are collected again after an automatic traversal of the sea flow or water layer under conditions determined by density differing from that of water. The carrier bodies are loaded and charged by depositing or accumulation of trace material, e.g. uranium concentration, on the carrier bodies. The carrier bodies are then conveyed to a further treatment location for isolating the accumulated and concentrated trace material. The carrier bodies are then again discharged into the flow or stream after being depleted.

Abstract: A process for recovering soluble uranium with an anion exchange system from carbonate-containing water. The process includes means for overcoming the deleterious effects upon the ion exchange system of carbon dioxide gas resulting from the carbonate-contents of the water in the presence of an acidic elutriate.

Abstract: High-level nuclear waste supernate is decontaminated of cesium by precipitation of the cesium and potassium with sodium tetraphenyl boron. Simultaneously, strontium-90 is removed from the waste supernate sorption of insoluble sodium titanate. The waste solution is then filtered to separate the solution decontaminated of cesium and strontium.

Abstract: Purifying a nitric acid solution containing U/Pu ions and contaminated by metal impurities by(a) oxidizing the U/Pu ions of the solution to the hexavalent form,(b) conducting the solution after oxidation through a cation exchanger column in which the impurities, especially americium, are retained,(c) flushing the cation exchanger column to remove impurities therefrom, which may be taken to waste processing or utilization plant.

Abstract: The invention is a process for the removal of radium from acidic aqueous solutions. In one aspect, the invention is a process for removing radium from an inorganic-acid solution. The process comprises contacting the solution with coal fly ash to effect adsorption of the radium on the ash. The radium-containing ash then is separated from the solution. The process is simple, comparatively inexpensive, and efficient. High radium-distribution coefficients are obtained even at room temperature. Coal fly ash is an inexpensive, acid-resistant, high-surface-area material which is available in large quantities throughout the United States. The invention is applicable, for example, to the recovery of .sup.226 Ra from nitric acid solutions which have been used to leach radium from uranium-mill tailings.

Abstract: A process as disclosed for recovering uranium values from a carbonate leach solution which comprises directly eluting a column of resin onto which uranium has been sorbed by flowing a concentrated acidic eluant through the column without preconditioning and/or post-conditioning the resin. The concentrated acidic eluant may be flowed upward or, preferably, downward through the column.

Abstract: A method and apparatus for recovering raw material, especially uranium, f natural waters, especially from the sea. Carrier bodies capable of sinking are permitted to pass, in a free fall, through a layer of water, especially a natural sea current or stream, by concentration on the carrier bodies, which are collected at an appropriate depth and are then conveyed from there for further treatment. Carrier bodies of inert material are used having a protected outer surface with a thin layer, capable of being concentrated, coated thereon. The distance of falling amounts to approximately 100 meters. The apparatus for carrying out the method includes a carrier body discharge located below water level. One end of a carrier body path has a collection device for collecting carrier bodies and is directed toward the conveyor path. The apparatus also has a conveying device operating especially hydraulically according to the principle of communicating pipes.

Abstract: Backwash water containing radioactive cruds of a non-filter aid type filter of the primary cooling water system of an atomic power plant is treated by leading the backwash water directly, or supernatant obtained by removing coarse cruds by settling in advance, to a waste resin settling tank for backwash water containing waste ion exchange resin powder from filter-demineralizer of the condensation-purification system of the atomic power plant, mixing the backwash water or the supernatant with the backwash water from the filter-demineralizer in the tank, thereby allowing the cruds contained in the backwash water or the supernatant onto the waste ion exchange resin powder, and settling the crud-adsorbed waste ion exchange resin powder, thereby separating and removing the cruds from the backwash water from the non-filter aid type filter. Recycle of fine cruds can be eliminated with enhanced percent crud removal, and recycle time of backwash water can be shortened.