Abstract: An improved method for treating leachate from a sanitary landfill is provided. The method includes the steps of adding a pH adjuster to elevate the pH of the leachate, such that ammonia nitrogen compounds, COD compounds, and VOCs form volatiles and heavy metals form insoluble compounds; combusting landfill gas to produce combustion products and to elevate the temperature of the leachate such that chemical activity is enhanced therein; gas stripping the volatiles from the leachate; precipitating the insoluble compounds from the leachate; and diffusing the combustion gases through the leachate to reduce the pH thereof to an acceptable discharge level.

Abstract: Acid water containing toxic levels (>0.1 ppm) of aluminum is treated to dissolve therein both silicate ions in an amount to create a solution containing at least 40, preferably at least 100, micromoles per liter of silicon and a silicon:aluminum ratio (based on metals) of at least about 6:1 and preferably 10:1 in the water to form a non-toxic complex with aluminum and alkali or alkali metal ions to increase the pH of the water. The preferred treatment agent is a hydraulic calcium silicate, in the form of cement clinker, optionally silicate-enriched with a soluble silicate.

Abstract: A process is disclosed for removing dissolved organics from an aqueous composition, said composition comprising water, carbon dioxide and dissolved organics, and said composition having a pH of 6.5 or less and an inlet organics concentration. The process comprises the steps of feeding said aqueous composition to a centrifugal separation zone, preferably to a hydrocyclone, depressurizing said composition in said centrifugal separation zone to regasify at least a portion of said carbon dioxide. An aqueous product stream is removed from the centrifugal separation zone wherein the concentration of said organics is less than said inlet organics concentration. The process is particularly useful in the cleanup of industrial wastewater, and also for removing organics from water produced in petroleum production operations.

Abstract: Barium sulfate scale is dissolved by contacting the scale with an aqueous solvent having a pH of about 10 to about 14, preferably about 12, and comprising a chelating agent comprising a polyaminopolycarboxylic acid or salt of such an acid, and a synergist anion. The solvent containing the dissolved scale is regenerated by acidifying the solvent in the presence of an anion which forms a precipitate of an insoluble salt of the alkaline earth metal of the dissolved scale. The precipitate is then removed from the solvent. Thereafter, the pH of the solvent is increased to a pH of about 10 to about 14, preferably about 12, to recover a regenerated solvent for reuse, in dissolving scale.

Abstract: A method and composition for treating wastewater streams is provided. The composition includes a zirconium salt and preferably a zirconium carbonate. In addition to the zirconium salt; a ferrate, a reducing agent, a weighting agent and an anionic coagulating agent can also be employed. The method includes the steps of adjusting the pH of a wastewater stream to between about pH 6.5 and about pH 14, adding the composition, precipitating contaminants from the wastewater stream and separating a solution having a reduced contaminants content therefrom.

Abstract: A system and process for recycling alkaline aqueous cleaners for electronic components. Such cleaners generally contain saponifiers which react with rosin flux on the electronic components to form rosin soaps. Spent cleaner is concentrated, the pH is lowered to cause a separation between the cleaner and the soils within the cleaner. The cleaner then is filtered to further remove any soils. The filtered cleaner is then reconstituted to a determined concentration and pH level and returned to the cleaning system.

Abstract: An effluent precipitation and neutralization chamber for mixing and neutralizing spent photographic developer and fixer. A baffle and long folded ribbons inside the chamber promote mixing of the developer and fixer. A source of iron ions such as fine steel wool is immersed in the fluids. Ion exchange between the steel wool and the photographic fixer recovers silver from the fixer. The desilvered fluid is diluted with wash water before it is discharged from the chamber. A wash water inlet tube is directly aligned with the discharge outlet opening in the chamber so that wash water can flow almost directly into the outlet tube to dilute the mixed and neutralized developer and fixer.

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 for recovering the chelating or complexing agents, particularly ethylenediaminetetraacetic (EDTA), used in chemical cleaning and decontamination operations performed to clean steam generators, especially nuclear powered steam generators, is provided. The EDTA, metal and radionuclide-containing aqueous waste stream is, optionally, first treated to remove the metals and radionuclides. The pH of the resulting liquor is then adjusted to less than 2.0, causing the precipitation of acid EDTA. The solid acid EDTA is recovered for reuse or disposal, as desired. The remaining liquid is treated as required to permit environmental disposal. Removal of the metals and radionuclides can be by sulfide precipitation or ion exchange and may be conducted before or after precipitation of the acid EDTA.

Abstract: A process for separating the grease, solids and water components from grease such as grease traps and fry grease. The grease is collected and introduced into a primary holding tank to effect primary crude separation. The grease is removed to a second stage separator for further concentration. The water and solids are separately directed to a second stage to separate these components. The separated water is treated suitable for discharge into a sewer. The solids are dried and the solids and grease are then suitable for re-use. In the preferred embodiment, the separators are centrifuges. Heating of the grease may also be necessary to achieve proper viscosity for handling and to remove bacteria.

Abstract: The process relates to the treatment of aqueous solutions of polyhydric alcohols to remove heavy metal components, oils, organic contaminants and, optionally, water. The process is particularly well suited for use in the treatment of spent antifreeze/coolant from the cooling systems of internal combustion engines.

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 precipitating and removing chromium compounds in which chromium is in the hexavalent state from aqueous liquids, particularly, alkaline earth metal or alkali metal chlorate-rich solutions containing chloride, chlorate, and bichromate ions produced by the electrolysis of brine. In the process, hydroxylamine, hydroxylamine sulfate, hydroxylamine formate or hydroxylamine hydrochloride is used as a reducing agent to react and co-precipitate at a neutral or acid pH with hexavalent chromium ions present in the aqueous liquid, the reaction and precipitation taking place, generally, at a pH of about 4.0 to about 6.5 and, a temperature of about 50.degree. C. to about 100.degree. C. Precipitated oxides and hydroxides of divalent and trivalent chromium can be removed, for instance, by filtration.

Abstract: A synergistic antimicrobial composition comprising a 2-alkyl-3-isothiazolone and a 3,4-dichloroanilide of the formula ##STR1## where n is an integer from 1 to 2, in a ratio to each other which exhibits synergism is disclosed.

Abstract: A process is disclosed in which ink contained in a water-wipe solution used in the intaglio printing of security documents is recycled after being refurbished. The water-wipe solution is neutralized; the ink is separated by filtration and refurbished before being utilized.

Abstract: A process for the purification of acid aqueous effluent contaminated with organic material is disclosed herein. The method includes the steps of: a) bringing the aqueous effluent in contact with an iron-containing material in particulate form, wherein the particles of iron are in the metallic state; b) subjecting the material to mechanical processing in contact with the aqueous effluent while dissolving at least part of the metallic iron; c) increasing the pH of the aqueous effluent after the mechanical processing step to an essentially neutral pH; d) causing precipitation of three-valent iron under oxidizing conditions; and e) separating the precipitate from aqueous phase of step d).

Abstract: A method and system for removing toxic substances such as selenium from industrial and agricultural drain water, and particularly refinery effluent liquor, achieves very high removal of the toxic substance economically, by a chemical reduction process. Preferably, the effluent liquor is first filtered, which ordinarily is effective to remove selenium suspended in the liquor. Next the liquor is heated, preferably to about 150.degree. F., and a reducing agent such as finely powdered iron is added to bring, for example, the selenium down from a +6 valence to +4 and lower valences. Sulfur is added to the slurry to greatly improve the effectiveness of the iron in reducing the liquor. The slurry is constantly agitated. After a reaction time which may be about 15 minutes, an oxidizing agent is added, with the temperature of the slurry then raised to at least about 180.degree., with continued agitation.

Abstract: A method of removing Cr.sup.+6 from a solution is provided. In removing the Cr.sup.+6, an effective amount of an alkali metal dithionite is added to the solution to reduce substantially all of the Cr.sup.+6 to Cr.sup.+3. A soluble material is provided in the solution which will form a precipitate. Further, the soluble material is selected such that it will coprecipitate and tie up any dissolved or colloidal Cr.sup.+3 formed as a result of the reduction of the Cr.sup.+6. In one embodiment, the solution is alkaline and preferably, the pH of the solution is reduced sufficiently such that the soluble material will quickly precipitate and form the coprecipitate material with the Cr.sup.+3. Thereafter, the solution is filtered to remove the coprecipitated material from the solution and thereby form a supernatant solution suitable for waste discharge which has substantially lowered chromium values. The precipitate has the Cr.sup.+3 tied up in an insoluble non-leachable form.

Abstract: Coal fines and suspended insoluble metals are flocculated from coal mine drainage waters by adding a polymeric tannin-amine compound.

Abstract: A process is disclosed for treating an aqueous waste stream containing a photoresist waste component. Under this process the pH of the waste stream is adjusted in a range from about 4.0 to about 6.0 and an additive is added to the waste stream in a concentration effective to separate a precipitant from the waste solution in the form of a non-sticky residue. The additive is selected from the group consisting of FeCl.sub.3, CuCl.sub.2, NH.sub.4 Cl, AlCl.sub.3, and combinations thereof.

Abstract: A chemical method of removing thiourea from spent hydrochloric acid cleaning solutions comprising the steps of: adjusting the pH to not less than 12 by addition of base to remove metal hydroxides; oxidizing thiourea to urea by the addition of at least a stoichimetric amount of oxidant per mole of thiourea; and further oxidizing urea to nonregulated/nonhazardous compounds by the addition of at least 3 moles of a hypochlorite per mole of urea. UV analysis confirms a greater than 98% removal of thiourea from solutions containing 0.4 to 2.7 wt. % thiourea after as little as 3 hours with an exotherm, .DELTA.t, of less than 105.degree. F.

Abstract: A high efficiency filter medium is placed in series with a water treatment clarification system for receiving the treated effluent discharged from the clarifier. The treated water is passed through the high-efficiency filter media for reducing the suspended solid constituent of the water to less than 10 ppm. The filter is supported in a open mesh carrier tray and is made of a polyester material adapted for collecting and entrapping the solid suspended particles in the clarified water discharge.

Abstract: A method for processing residual fixing-baths, whereby a residual fixing-bath after demetalization by means of sulfide or by means of electrolysis, is acidified with a mixture of nitric acid and sulphuric acid, and the precipitated sulphur is removed. A liquid suitable as a gas washing liquid for flue gases and/or liquid fertilizer component is also prepared by an integrated processing of two or three waste materials.

Abstract: Phosphoric acid wastewater treatment to substantially eliminate discharge of contaminants to the environment. Acid pond water from conventional wet-phosphoric acid manufacturing is replaced by gypsum pond water having a pH closely matching that of the surroundings. Essentially all fluorides are insolubilized and substantially all phosphoric acid is recovered, minimizing loss to the environment.

Abstract: The application relates to a process for removing nobler metal ions than iron, especially copper ions, from acidic process and waste waters by reduction under an inert gas atmosphere with carbonyl iron powders which have previously been subjected to a thermal treatment with hydrogen to remove nitrides and carbides. This process results in residual metal ion content <0.5 ppm and thus complete removal of the metal ions to be reduced.

Abstract: A method and composition for detackifying or coagulating and flocculating waterborne and solventborne paints with organofunctional silane compounds.

Abstract: A process for removing cyanide anions from waste waters using halogen-free ferric salts is disclosed. The process is particularly effective when treatment of cyanide waste waters is done by adding ferric sulfate while adjusting pH of the waste waters with a halogen-free acid, such as sulfuric acid, to a pH ranging from about 3.0 to 5.0.The ferric ferricyanides formed are agglomerated and flocculated using synthetic polymers along with whatever other dispersed or suspended solids may be present in the waste waters, and this dense sludge is separated in a clarifier. Cyanide removal is at least 80%, relative to initial cyanide concentrations, and preferably 90% removal or higher.Cyanide wastes from coke oven off gas scrubbing waters are particularly waste waters amenable to this treatment.

Abstract: A process for removing at least a portion of any iron, copper, nickel and chromium ions that are chelated by a alkylenepolyamine polyacetic acid or salt in an aqueous liquid waste. The process comprises the steps of (a) adjusting the pH of the liquid to above about 10; (b) adding sufficient sodium sulfide to react with at least a portion of the copper ions; (c) separating precipitated iron and copper compounds; (d) adding nitric acid to adjust the pH to the range of about 6 to 8; (e) adding sufficient sodium nitrite to the liquid to react with at least a portion of the nickel and chromium present; (f) heating the liquid to above about 575.degree. F. for at least about 15 minutes to facilitate precipitation of nickel and chromium; and (g) separating precipitated solids to leave a non-hazardous filtrate.

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: A method of removing undesired ions, such as chlorine, hypochlorite, chromium, cyanide and heavy metal ions, from an aqueous preparation containing one or more of said ions consists of adding to the aqueous preparation an effective amount of magnesium bisulfite to inactivate the undesired ions and then adjusting the pH of the mixture to an appropriate pH. Compositions containing magnesium bisulfite and divalent and trivalent ions are disclosed.

Abstract: A water quality improvement process is provided for acid water containing sulphate and/or sulphite ions. The water is continuously fed into a fluidized bed containing calcium carbonate particles. The water consumes calcium carbonate and has its pH increased while calcium sulphate CaSO.sub.4 and/or CaSO.sub.3 are produced.

Abstract: A process for chemically modifying at least one contaminant component in an aqueous-based material comprising: contacting at least one contaminant component in an aqueous-based material with at least one metal component selected from the group consisting of vanadium components in which vanadium is present in the 5+ oxidation state in an amount effective to promote the chemical modification of the at least one contaminant component in the aqueous-based material, iron components in which iron is present in the 3+ oxidation state in an amount effective to promote the chemical modification of the at least one contaminant component in the aqueous-based material, manganese components in which manganese is present in the 3+ oxidation state in an amount effective to promote the chemical modification of the at least one contaminant component in said aqueous-based material and mixtures thereof, and at least one oxygen transfer agent in an amount effective to do at least one of the following: maintain at least partially

Abstract: Process for softening hard water by precipitation of calcium carbonate. The hard water is rendered alkaline, e.g. by the addition of sodium hydroxide, and is then contacted with a large excess of calcium carbonate crystals whose size does not exceed 100 microns, whereby precipitation occurs within a short contact time of the order of 2-60 seconds. Upon separation of soft water from calcium carbonate the bulk of the latter is recirculated and excessive amounts are removed.

Abstract: Barium sulfate scale is dissolved by contacting the scale with an aqueous solvent having a pH of about 10 to about 14, preferably about 12, and comprising a chelating agent comprising a polyaminopolycarboxylic acid or salt of such an acid, and a synergist anion. The solvent containing the dissolved scale is regenerated by acidifying the spent solvent with an acidic chelating agent such as EDTA or DTPA, preferably DTPA, that release alkaline earth cations which react with sulfate ions present in the solvent to form a precipitate of an insoluble salt of the alkaline earth metal. The precipitate is then removed from the solvent by settling/decanting, filtering, or centrifuging. Thereafter, caustic is added to increase the pH of the solvent to a pH of about 10 to about 14, preferably about 12, to recover a regenerated solvent for reuse, in dissolving scale.

Abstract: A method of treating wastewater including a heat-curable (meth)acrylic monomer-containing composition, at temperature below that necessary to effect heat-curing of the composition. The wastewater may be produced by aqueous washing of porous parts impregnated with a sealant composition containing such monomer. The monomer-containing wastewater is (1) adjusted in pH to a value in the range of from about 8 to about 10, and (2) contacted with an effective amount of a reducing agent which is polymerizingly effective for the monomer, to yield corresponding polymer from the monomer. The wastewater is mixed with a cationic flocculating agent in sufficient quantity to flocculate the polymer in the wastewater, and the resulting wastewater is physically separated to recover a monomer- and polymer-reduced wastewater effluent which may be discharged to receiving waters.

Abstract: The present invention relates to a method of reducing the content of halogenated organic compounds in the spent bleach liquor from the bleaching of lignocellulose-containing material with compounds containing halogen, wherein the spent bleach liquor, in a stage where no essential delignification or bleaching of the pulp takes place, is maintained at a pH of from 2.5 up to about 10, and wherein the residence time and the temperature are selected such that the amount of dissolved halogenated organic substances in the spent bleach liquor is reduced by at least 30%.

Abstract: A process for reducing arsenic levels in a solution containing sulfuric acid, water, and arsenic acid by adding copper or a copper-containing compound to the solution to form dissolved copper arsenate, adding alkali solution to precipitate the copper arsenate and to neutralize arsenic and sulfuric acid. The copper arsenate is separated, and the remaining solution is treated with a ferric compound and an alkali in order to form ferric arsenate to remove residual arsenate. The ferric arsenate is separated and the remaining solution contains less than about 0.79 ppm arsenic. The ferric compound is added so that the ratio of iron to arsenic is about 8:1 to about 10:1 and alkali is added during this step to adjust the pH to from about 5 to about 7.

Abstract: A method of treating wastewater containing (meth)acrylic monomer, such as is produced by aqueous washing of porous parts impregnated with a sealant composition containing such monomer. The monomer-containing wastewater is (1) adjusted in pH to a value in the range of from about 8 to about 10, and (2) contacted with an effective amount of a reducing agent which is polymerizingly effective for the monomer, to yield corresponding polymer from the monomer. The wastewater is mixed with a cationic flocculating agent in sufficient quantity to flocculate the polymer in the wastewater, and the resulting wastewater is physically separated to recover a monomer- and polymer-reduced wastewater effluent which may be discharged to receiving waters.

Abstract: This invention relates to a process for removing copper ions from highly acidic waste water generated during the manufacture of dyes or pigments or intermediates thereof. The waste water is exposed at a pH less than about 1 to a bed of suspended iron particles, preferably a fluidized bed of iron particles, having a particle size of from about 200 to about 950 micrometers.

Abstract: A highly stable dispersion e.g. an oil-in water emulsion having a pH of from about 4 to about 12 is destabilized by treatment with a composition comprising a precipitant e.g. aluminum sulphate, a clay and a marl.

Abstract: An effluent precipitation and neutralization chamber for mixing and neutralizing spent photographic developer and fixer. A baffle and long folded ribbons inside the chamber promote mixing of the developer and fixer. A source of iron ions such as fine steel wool is immersed in the fluids. Ion exchange between the steel wool and the photographic fixer recovers silver from the fixer. The desilvered fluid is diluted with wash water before it is discharged from the chamber.

Abstract: A composition for treating toxic metals in solid waste, sludge or slurry is provided. The composition includes a reducing agent such as ferrous sulfate or sodium sulfite and a fixative containing solid calcium oxide or solid magnesium oxide. The composition may also include an acid such as sulfuric acid.

Abstract: A process for separately removing zinc and iron from acidic wastewater. The process involves adding alkali metal hydroxide to the acidic wastewater (below about pH 4) to achieve a first pH of about 4.8 to at most about 5.4 and precipitate an iron hydroxide-containing precipitate at this pH. The precipitate from the wastewater is separated and then additional alkali metal hydroxide is added to achieve a second pH in the range from about 8.8 to about 9.4. A zinc hydroxide containing precipitate forms at this second pH and is then recovered by filtration.

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. When chelating agents are present, they 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.

Abstract: A method for treating wastewater having a pH of between about 0.1 and 14 and containing dissolved heavy metals, in which a substantial portion of the heavy metals is precipitated as crystallized solids embedded within an insoluble monoclinic calcium sulfate crystal to produce a purified effluent having a pH of between 8 and 9.

Abstract: A process for removal of adsorbable organic chlorine (AOX) in which the acid-soluble AOX present in kraft chlorination (C.sub.D) effluents are destablized and converted to inorganic chloride by pH shift using the alkalinity and acidity sources available at the mill; C.sub.D effluent, typically having a pH of 1-2 and E.sub.1 effluent, typically having a pH of 9-12 can be mixed in various proportions to achieve a pH between 6.5-9.0 or the C.sub.D effluent is adjusted in pH to 6-11 with an alkaline composition so taht alkaline hydrolysis as well as precipitation of organic material occurs and the treated effluent contains less AOX than present in the original untreated effluents; the AOX removal is enhanced substantially by (i) the presence of a sulphide or (ii) by carrying out the alkaline treatment at elevated temperature and pressure.

Abstract: The invention involves a process as well as apparatus for the separation of arsenic from waste material. The process includes precipitation of arsenic in the form of low solubility calcium magnesium arsenates by adding calcium and magnesium compounds to the waste, separation of calcium magnesium arsenates, putting the waste in contact with an ion exchanger, regenerating the ion exchanger after reaching the charge limit, adsorptively separating the arsenic by putting the waste in contact with active carbon, and separating the charged active carbon by itself or along with precipitation products. The process allows for a separation of arsenic from waste which is hard to be treated or contains heavy metals such as lead or contains sulfates to residual amounts as low as <0.3 mg As/l.

Abstract: A two-stage process for treating acidic gypsum pond water for reuse or for discharge is disclosed. The first stage blends raw acidic pond water with recycled lime-treated slurry from the second stage of the process. The resulting elevation in pH causes CaF.sub.2 and SiO.sub.2 to precipitate and the precipitated material is discarded onto the gypsum storage area. The supernatant water can be used in the wet grinding mill and/or further treated in a second stage with lime to produce treated water which meets government environment standards for discharge. The slurry of calcium phosphate formed in the second (liming) stage is recycled to the first stage.

Abstract: A method for reducing industrial or urban effluent COD is described, comprising treating said effluents with an aqueous solution of alkaline and/or ammonium salts or humic acids perpared by the dry oxidation of coal with oxygen or oxygen/nitrogen mixtures at a temperture of between 120 and 350.degree. C. at an oxygen partial pressure of between 0.1 and 10 ata for a contact time of between 15 and 600 minutes, followed by extraction of the crude oxidation product with an alkaline and/or ammoniacal solution, characterised in that said aqueous solution is fed into effluent, the pH of which has been previously adjusted to between 1 and 3.5, to the extent that the humic acid salts which exhibit flocculating action are in a concentration of less than or equal to 2000 mg/1 of effluent.

Abstract: A method for separation of PVA from an aqueous solution thereof such as the waste water containing PVA from the pretreatment of a textile product, in which a peroxosulfate such as ammonium peroxosulfate is added to an aqueous PVA solution, particularly in an acidic condition with addition of sulfuric acid, at a temperature above 70.degree. C. for the separation of PVA, and as a result the thus separated PVA contains only a small amount of water in the range of about 60-70% and can easily be treated.