Abstract: Process water from pulp manufacture is purified in a separator device by mechanical or a combination of mechanical and chemical methods and is thereafter evaporated, at least part of the concentrate resulting from the evaporation being recycled and mixed with the process water fed into the separator device. In a preferred embodiment, a precipitant is added to the mixed water comprising the process water and the concentrate. The part of the concentrate not recycled and mixed with the process water is supplied, optionally after further evaporation, with an acid to a pH of 1-5, whereupon resulting flocs and precipitates are removed in a separator device.

Abstract: A lime-treatment method is disclosed to neutralize acidic waters containing heavy metals and sulphate and precipitate the metals as hydroxides along with calcium sulphate solids which are called sludge. The method comprises neutralizing the water in two reactors, the pH of the first reactor being increased to 4-4.5 using a predetermined amount of recycled sludge to precipitate only ferric hydroxides whereas other metal hydroxides coming from the recycled sludge are dissolved, the pH of the second reactor being increased to 9-10 using a mixture of lime and a small amount of the sludge recycled to the first reactor; feeding the ferric hydroxides precipitated in the first reactor to the second reactor to act as nuclei in the second reactor to promote crystallization; and introducing air into the second reactor to oxidize ferrous iron to less soluble ferric iron which results in formation of a more stable sludge compared to ferrous sludge.

Abstract: The process relates to the reinhibition of recycled antifreeze/coolant. The process is particularly well suited for use with recycled, used antifreeze/coolant from the cooling systems of internal combustion engines.

Abstract: A flocculant for water treatment containing a highly polymerized silicic acid solution having a high concentration of SiO.sub.2 and an extremely low concentration of alkali metal substance, and a method for producing such flocculant. The silicic acid solution is prepared by treating an aqueous solution of an alkali metal silicate such as water glass to remove alkali metal and allowing the solution to liquefy after once gelling. The flocculant may further contain a water soluble metal salt such as ferric chloride or ferric nitrate.

Abstract: A process is provided for preparing preferred iron humate products. The preferred iron humate products provide iron and other nutrients and organic matter for vegetation and supplementation of animal feedstocks. The preferred iron humate products are produced by using an iron salt coagulant that is relatively free of heavy metal contaminants and reacting the iron salt coagulant with naturally occurring humic substances such as those found in natural surface waters used in drinking water treatment facilities. According to the invention, iron is stoichiometrically reacted at a controlled pH with the humic and fulvic acid fractions in the water to precipitate an iron humate product precipitate. A preferred concentration of iron salt coagulants is used in order to minimize the formation of iron hydroxides.

Abstract: A process for purifying an acidic technical-grade iron chloride solution formed from cyclone dust from the production of TiO.sub.2 in accordance with the chloride process by adjusting the pH with a first neutralizing agent and thereafter introducing the pH adjusted solution in a controlled manner into a solution containing a second neutralizing agent. In this process undesired ions which are to be separated, such as chromium, vanadium, zirconium and/or niobium, precipitate in the form of efficiently filterable hydroxides which can be separated industrially under economical conditions by filtration. The filter cake is non-hazardous and can safely be disposed of by dumping. Calcium carbonate is the preferred neutralizing agent, and the pH adjustment may also advantageously be effected by using scrap iron or by using iron sinters with reduction of any Fe(III) ions before the second neutralization step.

Abstract: An improved process is provided for the steam conversion of dilute printer ink washup fluids, and especially those of a single color, in order to permit reuse of the ink fraction of the fluids as reconstituted printing inks. Preferably, the washup fluids are acidified to create a pin floc therein, with a final pH of from about 2-7; the acidified fluid is then contacted with a stream of steam in a hydroheater (16) in order to convert the residual ink fraction and permit reconstitution thereof into printing ink. The acidifying agent is preferably an acid polymer or an inorganic acid such as HCl or H.sub.2 SO.sub.4.

Abstract: A method for removing dissolved fluoride from waste water involving a multiple stage process which includes a first step of contacting a solution comprising calcium fluoride with a calcium ion source to form a first precipitate and a second step of contacting the first precipitate comprising the calcium ion source with the fluoride-containing waste water solution to form a second precipitate. A first portion of the solution that has been treated directly with the waste water and which contains the second precipitate, is preferably recycled, along with calcium fluoride, to the first step for contact with the calcium ion source. A second portion of the solution treated with the waste water may be transported to a thickener or gravity settling step, and/or to a solids-dewatering step wherein standard filtration equipment may be used to produce a filter cake having a controlled particle size distribution.

Abstract: A highly flexible multi-step treatment technology for chemical fixation and stabilization of leachable chromium, particularly hexavalent chrome, in contaminated soils, solid wastes, concrete, sludge, sand and gravel and waste waters is disclosed. The process comprises reducing hexavalent chromium to chromous (Cr.sup.2+) and chromic (Cr.sup.3+) forms in the presence of water under alkaline conditions and fixing the reduced chromium forms with phosphate.The process reduces Toxicity Characteristic Leaching Procedure chromium levels below the regulatory threshold of 5 mg/l as required by the USEPA.

Abstract: Heavy metal ions react with ferrous dithionite in acidic aqueous solution. They are reduced to metallic particles that are suitable for recycling and reuse when recovered from the acidic water. Chelating agents that are present are deactivated by bonding to the ferrous ions. Ferrous dithionite, (FeS.sub.2 O.sub.4) is either generated in-situ or ferrous ions and dithionite ions can be provided by other methods. An alkali metal hydroxide is utilized to precipitate remaining heavy metal ions including ferrous and ferric ions.

Abstract: A method of treating chemical liquid, and in particular photographic effluent, to render it more environmentally acceptable, by the addition to an alkaline solution of a salt of a Group III or transition metal to complex with and precipitate out a sequestering agent. Preferred salts are the sulphate, halide, oxychloride or nitrate of aluminium.

Abstract: Metallic iron particles are added to an aqueous solution containing hexavalent chromium and mechanically agitated. Enough of the surface of the iron particles remains precipitate-free to reduce substantially all the hexavalent chromium to trivalent chromium. Adjustment of pH allows the formation of insoluble precipitates which may be separated from solution using conventional techniques. The properties of the aqueous electrolyte solution are retained, and the solution may be reused.

Abstract: A process of treating water to remove metal ion contaminants contained therein, said metal ion contaminants selected from the group consisting of metals in Groups 8, 1b, 2b, 4a, 5a, or 6a of the periodic table, lanthanide metals, and actinide metals including transuranic element metals, by adjusting the pH of a metal ion contaminant-containing water source to within the range of about 6.5 to about 14.0, admixing the water source with a mixture of an alkali or alkaline earth ferrate and a water soluble salt, e.g., a zirconium salt, in an amount sufficient to form a precipitate within the water source, the amount the mixture of ferrate and water soluble salt effective to reduce the metal ion contaminant concentration in the water source, permitting the precipitate in the admixture to separate and thereby yield a supernatant liquid having a reduced metal ion contaminant concentration, and separating the supernatant liquid having the reduced metal ion contaminant concentration from the admixture is provided.

Abstract: A process is disclosed wherein arsenic dissolved in wastewater or groundwater is removed from solution by precipitation thereof as calcium arsenate formed by the reaction of the arsenic with lime or hydrated lime in a heated solution at a pH of about 11 to about 13. It is preferred that the arsenic is first converted by oxidation to its pentavalent form.

Abstract: Aqueous phosphorus wastes from the electric furnace production of phosphors and containing heavy metal bearing particulates are treated with lime whereby the phosphorus is converted into useful phosphorus compounds and the heavy metals rendered sufficiently non-leachable to permit their release into the environment. The treatment is conducted above about 60.degree. C. at a pH of between about 11.0 to 12.5.

Abstract: Converting wet-process phosphoric acid operations, to minimize and nearly eliminate discharge of contaminants to the environment, by generation, use, and treatment of new and unique process waters. Fluorides and other contaminants soluble under acidic conditions are insolubilized, and substantially all phosphoric acid is recovered. Acid pond water from conventional wet-process phosphoric acid manufacturing is replaced by neutralized gypsum stack water having a pH closely matching that of the surroundings. Both air and ground water contamination are reduced to essentially negligible levels.

Abstract: A treatment method for removing arsenic from water includes conditioning the water with one more additives including an iron salt, an acid, and an oxidant until the water contains more ion than arsenic, is acidic, and has an ORP of about plus 600 mV. A reagent is then added to the conditioned water until it becomes basic and the water and additives are then reacted in a reaction chamber wherein iron and arsenic are co-precipitated in the form of iron arsenate and iron hydroxide or iron oxide. Treated water is then separated from the precipitate by settling of filtering.

Abstract: A new slow releasing particulate iron humate agricultural nutrient composition exhibiting substantially complete solubility of its iron content in soil solutions as indicated by neutral citrate solubilities, and almost no solubility in water, and a new method for preparing the composition. The method comprises admixing and coreacting iron humate with about equimolar amounts of a divalent metal oxide, an aqueous hydroxide of a monovalent Lewis acid, and a water soluble inorganic phosphate. The iron humate amounts to between 20 and 70 percent of the nutrient particles, and the reaction is carried out at temperatures between 60.degree. and 150.degree. C. for between 4 and 25 minutes.

Abstract: In the process of removing heavy metals from aqueous solutions (groundwater) by precipitation of a salt thereof, an oxidizing agent is optionally used to increase the valence of said metal, and a precipitation-enhancing agent is added to maximize particle size of the precipitate and to facilitate its separation from said solution.

Abstract: This invention provides a fast and efficient method and process to remove lead from washwater streams that are part of the deleading process. By employing a two step process using epsom salts as a precipitating chemical to convert dilute lead concentrations into a very slightly soluble solid and then processing the small residue with a reverse osmosis unit the lead is totally removed from part of the water and the lead containing reject stream from the reverse osmosis unit is recucled through the process to again treat the lead. A reduction in total waste volume of over 90% is achieved.

Abstract: A process is disclosed for the removal of dissolved heavy metals from aqueous solution contaminated therewith wherein at least one of said heavy metals is reacted with a water-soluble inorganic sulfide or hydrosulfide at a defined elevated temperature and a controlled pH of between about 2 to about 3.5 to thereby precipitate heavy metal sulfide, and thereafter separating the precipitate from the filtrate.

Abstract: A method has been devised for removing chromium ions from a chromium ion containing liquid and recovering chromium oxide in a usable form by (a) adjusting the temperature of the liquid to an optimal temperature to maximize reduction and simultaneous precipitation of the chromium oxide; (b) adding a reducing agent to the liquid to form a mixture, where the reducing agent is at least one inorganic sulfur compound selected from the group of sulfur compounds where sulfur is in the 4.sup.+ oxidation state; and (c) adjusting the pH of the mixture to a pH between 5 and 7; (d) optionally further adjusting the pH of the mixture to a pH between above 7 to 12; and (e) separating the chromium from the mixture.

Abstract: The invention describes the use of molybdenum compounds in circulating waters of wet precipitators of spray coating units for detackifying and coagulating paints and/ or varnishes, waxes and other organic coating compositions, and a process for detackifying and coagulating paints and/ or varnishes, waxes and other organic coating compositions by means of molybdenum-containing coagulants.

Abstract: A process for selectively recovering dissolved heavy metals from a solution is disclosed that involves selectively reacting a xanthate with such dissolved heavy metals. Selective reaction of a xanthate with selected dissolved heavy metals is accomplished by conducting the reaction under conditions such that only some of the heavy metals react with the xanthate, to the exclusion of reaction with other dissolved heavy metals. Selectivity of the reaction is particularly influenced by the pH at which the reaction occurs. Typically, the reaction should occur at a pH below about 4.0. Xanthates, once reacted, can be separated from the heavy metal xanthate reaction product and recycled for use within the process. Purified heavy metal product can be produced if desired.

Abstract: Metals that form sparingly soluble sulfides are removable from industrial wastewaters by adding a precipitant comprising a suspension obtained by mixing sulfur, an iron(II) salt, water and a base, adjusting the wastewater pH to >4, and separating off the resulting sulfidic precipitate in a conventional manner.

Abstract: There is disclosed a method of treating a solution, e.g., an alkaline or acidic solution, containing heavy metals ions therein. With respect to alkaline solutions, the method includes providing a body of the solution; contacting the body with a material such as carbon dioxide to change the pH, e.g., to lower the pH to a pH in the range of 9 to 10.5; then treating the solution to further change the pH and cause precipitation of hydroxides, including chromium hydroxide; and separating the hydroxide precipitates from the solution to provide a substantially neutral solution having a reduced amount of chromium ions, for example, contained therein.

Abstract: A method for treating liquid wastes containing photoresist polymers and heavy metals is disclosed. The method includes adding to the liquid wastes an aqueous solution of water soluble FE.sup.+3 and Al.sup.+3 salts at a pH in the range of from about 0.1 to 1.0, and a water soluble salt of Mg.sup.+2 or Ca.sup.+2. The ratio of the amount of the Fe.sup.+3 and Al.sup.+3 to the amount of the Mg.sup.+2 or Ca.sup.+2 is in the range of from 2 to 3 moles to 1 to 3 moles. A precipitate containing the heavy metals and photoresist polymers is formed.

Abstract: A separation medium for use in protein separation comprising a water-insoluble matrix carrying a plurality of polyamine groupings, the polyamine groupings having at least three basic nitrogen atoms, the basic nitrogen atoms being separated from each other by a chain of at least two intervening carbon atoms, there being a total of 5 such intervening carbon atoms when there is a total of three nitrogen atoms in each polyamine group, which may be used for at least partially purifying factor VIII.

Abstract: A process is provided for preparing preferred iron humate products. The preferred iron humate products provide iron and other nutrients and organic matter for vegetation. The preferred iron humate products are produced by using an iron salt coagulant that is relatively free of heavy metal contaminants and reacting the iron salt coagulant with naturally occurring humic substances such as those found in natural surface waters used in drinking water treatment facilities. According to the invention, iron is stoichiometrically reacted at a controlled pH with the humic and fulvic acid fractions in the water to precipitate an iron humate product precipitate. A preferred concentration of iron salt coagulants is used in order to minimize the formation of iron hydroxides which generally provide low iron availability to the plant. A more readily soluble iron humate complex is produced by the reacting and or blending of the iron humate residue with various nitrogen containing sources.

Abstract: A process for removing dissolved heavy metal from an aqueous solution is provided where the aqueous solution is mixed with a source of ferrous ion and dithionite ion in a first step at acidic pH to reduce and permit removal of the heavy metal. Solution from the first step is reacted in a second step with hydroxide slurrys obtained from third and fourth steps. A second solution from the second step is reacted in a third step with an alkali composition and a third solution. The third solution is reacted with a chelating agent for iron and an oxidizer in a fourth step. A solution of chelated iron from the fourth step is disposed of.

Abstract: Blocks, weighing about 35 lbs., formed of a homogeneous mixture of about 75% gypsum and 25% lime, are strategically placed in surface water that is being damaged by acid rain, where, by timed release of lime, the pH of the water is maintained at about 6.5 pH.

Abstract: An effluent precipitation and neutralization chamber for mixing and neutralizing spent photographic developer and fixer. The fixer inlet discharging into a vertically oriented conduit located within the vessel, which contains iron therein and defines a gravity flow path for flow of the fixer within the vessel from the inlet to the bottom of the vessel. A layer of steel wool is positioned on the bottom of the vessel in the flow path of the fixer. Baffles inside the chamber promote mixing of the developer and fixer. The desilvered fluid is diluted with wash water before it is discharged from the chamber. A wash water inlet tube is aligned with an open ended vessel that surrounds the discharge outlet to dilute the mixed and neutralized developer and fixer.

Abstract: A method for removing ammonia, or ammonia and phosphates from industrial agricultural or household effluents by causing precipitation as magnesium ammonium phosphate by means of a liquid reagent containing magnesium and phosphate ions and an acid. The effluents have more than 1 gle of ammoniacal nitrogen and the pH is adjusted to between 9 and 11 after addition of the liquid reagent.

Abstract: A process and equipment is disclosed for minimizing sludge formation in removal of chromium and heavy metals from chromium contaminated groundwater by using sodium sulfite for oxygen removal thereby minimizing the amount of ferrous salt necessary for reduction of chromium VI to chromium III in an alkaline solution and also minimizing the amount of excess iron salt to coprecipitate as an hydroxide to effect essentially complete removal of other heavy metals.

Abstract: For economical and assured separation of chromium, vanadium and titanium ions from acidic waste waters, which accrue in great quantities in preparation of titanium dioxide, the pH is first raised to around a value of 3 by addition of dolomite brick powder. Directly thereafter, the pH is fine tuned into the range of 4.3 to 4.7 through addition of calcium hydroxide and/or sodium hydroxide, and the hydroxides are separated with the aid of a flocculating agent. Since iron ions and calcium ions remain mainly dissolved in the waste water through such selective precipitation, only a relatively small volume of slush has to be disposed of.

Abstract: A method and apparatus for treating a surface of an aluminum substrate for a printing plate includes treating the substrate surface with a treatment liquid being circulated, separating and discharging aluminum ions from a portion of the treatment liquid, recovering a sodium hydroxide solution from the treatment liquid, mixing the recovered sodium hydroxide solution with the treatment liquid being circulated, and maintaining a predetermined concentration of aluminum ions in the treatment liquid to be used. A portion of the treatment liquid containing sodium aluminate solution is mixed with aluminum slag containing an amorphous aluminum hydroxide produced at the time of neutralization of a waste acid and a waste alkali produced during surface treatment to thereby supersaturate the sodium aluminate solution, crystallize the aluminum hydroxide, and recover the sodium hydroxide solution to be returned to a liquid control tank to maintain a predetermined concentration of aluminum ions in the treatment liquid.

Abstract: A method for treating waste water such as that from an industrial processing facility comprising the separation of the waste water into a dilute waste stream and a concentrated waste stream. The concentrated waste stream is treated chemically to enhance precipitation and then allowed to separate into a sludge and a supernate. The supernate is skimmed or filtered from the sludge and blended with the dilute waste stream to form a second dilute waste stream. The sludge remaining is mixed with cementitious material, rinsed to dissolve soluble components, then pressed to remove excess water and dissolved solids before being allowed to cure. The dilute waste stream is also chemically treated to decompose carbonate complexes and metal ions and then mixed with cationic polymer to cause the precipitated solids to flocculate. Filtration of the flocculant removes sufficient solids to allow the waste water to be discharged to the surface of a stream.

Abstract: The invention relates to a process for the purification of aqueous solutions polluted by nitrate ions. This process is characterised in that it consists in precipitating hydrated double or mixed calcium nitroaluminates, such as, in particular, hydrated calcium mononitroaluminate, by adding at least one agent supplying the element aluminium and at least one agent supplying the element calcium to the solutions to be treated, the overall mole ratio of the element aluminium to nitrate, Al/NO3, being superior to 1 and the overall mole ratio of calcium to nitrate, Ca/NO3, being superior to 2, and in that the precipitation reaction is performed with stirring and at a basic pH, preferably above 10.5.The process according to the invention is intende, in particular, to the treatment of polluted waters such as municipal waste water and factory effluents and to the treatment of liquid manure.

Abstract: Wastewater contaminated with heavy metals is treated in a multi-stage process. In a first stage, wastewater is treated with an effective amount of calcium oxide and/or calcium hydroxide in the form of lime to adjust the pH so that various metals in the water become insoluble. Gypsum formation may also occur if sulfate ions are present in the wastewater. In a second stage, an effective amount of sodium carbonate is added in the form of soda ash to allow formation of calcium carbonate. In a third stage, a coagulant, preferably a polymer, is added to facilitate the formation of a sludge comprising heavy metals, gypsum and calcium carbonate. In a final stage, the pH of the resulting effluent may be adjusted with a suitable acid, such as hydrochloric acid, to attain acceptable discharge requirements. The sludge formed is substantially stable and dewatered and has low toxic metal leaching characteristics.

Abstract: A decontamination treatment of process water is disclosed herein originating from electroplating/metal finishing and etching operations wherein the process water is loaded with heavy metal ions. The inventive process combines predetermined quantities of alkali/acid solutions together with a quantity of Sodium Humate so as to produce a disposable sludge which is environmentally safe and poses the least risk for leeching of harmful metals from the resultant sludge.

Abstract: In the process of removing heavy metals from aqueous solutions by precipitation of a salt thereof at increased pH, multiple stage precipitation by upward stepwise pH adjustment and solid separation at each stage is used to facilitate the manufacture of a product of high purity.

Abstract: A process is described for regenerating and recycling a contaminated solution recovered from an aluminum or tin washer process wherein the contaminated solution contains contaminants comprising inorganic soils, organic soils, or both as a result of the use of the solution in the washer process, which comprises(A) regenerating said solution by(A-1) extracting said contaminants from the solution in a manner which does not substantially reduce the amount of any chemicals present in the solutions prior to use; and(A-2) selectively replenishing chemicals as required; and(B) recycling the regenerated solution to the washer process. The process of the present invention significantly reduces the amount of waste water containing chemicals which must be discarded or treated in waste treatment facilities. The process also reduces the amount of process chemicals and water necessary for maintaining the washer processes used for aluminum and tin coil and container washer processes.

Abstract: Sodium Aluminate when used to adjust pH of paint detackifying systems improves the efficiency of polymeric paint detackifiers used in the detackification of paint from paint spray booths and similar equipment.

Abstract: The present invention provides a composition and process for the treatment of waste water containing chromium compound, for example water from a plating operation which includes significant concentration of a toxic chromium compound such as chromic acid. The chromium bearing solution is mixed with sufficient amount of hydrazine which can include selected minor concentrations of a cobalt salt to react with the chromium compound and render it insoluble. The chromium bearing water is introduced to a vessel which can have a baffle so that water introduced on one side of the baffle flows along a side of, then under the baffle and overflows on the other side. The hydrazine, which can include cobalt salt, is introduced to the incoming water at a rate to control the pH of the effluent from the vessel at a selected value of pH sufficient to remove all chromium from the effluent.

Abstract: The present invention relates to a method and an apparatus, in which the quality of a large amount of water and/or the quantity of dissolved oxygen in said water is improved and which are characterized in that water, in which slaked lime is dissolved in advance, and/or water of high oxygen content, which is generated in advance, is supplied into water pumped by an intermittent pneumatic water pumping unit so that the water having the slaked lime dissolved therein and/or the water of high oxygen content is diffused in the large amount of water.

Abstract: A method has been devised for removing chromium ion from a chromium ion containing liquid and recovering chromium oxide in an usable form by (a) adjusting the temperature of the liquid to an optimal temperature to maximize reduction and simultaneous precipitation of the chromium oxide; (b) adding a reducing agent to the liquid to form a mixture, where the reducing agent is at least one inorganic sulfur compound selected from the group of sulfur compounds where sulfur is in the 4.sup.+ oxidation state and (c) adjusting the pH of the mixture to a pH between 5 and 7.

Abstract: The use of aluminum sulfate to neutralize alkaline solutions yields a gelatinous precipitate. When neutralization of the solution causes other materials to precipitate along with the gel, filtration of the precipitated materials is very difficult because of the gel. The addition of water soluble magnesium, aluminum, and/or calcium salts as primary neutralizing agents for an alkaline stripper solution of a photoresin, followed by the acidification of the resulting slurry to a pH of from about 2 to about 3 gives a slurry of the precipitated resin which may be filtered quickly.

Abstract: Process for the recovery of copper from copper-containing industrial waste waters, in which the ionogenic copper or the copper in complex form is firstly reduced with sugar, then with dithionite, and is separated in metallic form.

Abstract: An apparatus for producing ultrapure water includes a cation exchange resin tower, a decarbonation tower, an anion exchange resin tower, and a pH adjustor for changing the zeta potential of the impurities contained in water. The pH value is adjusted to aggregate or ionize the impurities. The apparatus can be controlled so that the treated water is introduced into a reverse osmosis unit or an oxidation tower and an after reverse osmosis unit according to the quality of the treated water.

Abstract: A process for the precipitation of aqueous plastics dispersions containing polyvinyl alcohol, preferably from waste waters, and separation of the polymeric solids content, which comprises adding the following to the dispersion in order, with thorough mixing:a) a boric acid component,b) a basic compound for making the pH alkaline, thenc) an iron salt andd) a cationic polymeric polyelectrolyte, and isolating the precipitate which forms in the alkaline medium. The process according to the invention is advantageously applicable in all relevant sectors of technology and waste water treatment in which polymer dispersions containing polyvinyl alcohol are used or have to be disposed of, and where waste waters in which dispersions containing polyvinyl alcohol are present have to be processed. Degrees of clarification of more than 95% can be achieved.