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: 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: 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 is provided for selectively treating flocculated heavy metal contaminated iron-based sludges from an industrial waste water treatment process. The method removes the heavy metal contaminants with a minimum loss of the iron therein. The method comprises dissolving the sludge in hydrochloric acid to produce a ferric chloride solution. The solution is filtered to remove precipitated heavy metal salts, such as lead chloride. The filtrate containing the remaining heavy metal chlorides and ferric chloride is then cooled or otherwise treated to remove additional heavy metal chlorides. The remaining ferric chloride based solution is then reduced (exposed to iron powder) to a ferrous chloride solution and heavy metals. After filtration of any additional precipitated heavy metals, the ferrous chloride solution is ready for recycling.

Abstract: A chemical process for selectively removing organoselenium compounds and selenate from water supplies. The process utilizes a combination of transition metal selected from the group consisting of nickel and copper and an electropositive metal selected from the group consisting of magnesium and aluminum to effectively remove selenium whether present in the water as organic or inorganic compounds or in ionic or non-ionic form.

Abstract: A method to reduce dissolved silver present in spent, waste, photographic processing fluids containing thiosulfate, is described. This process involves adjusting the pH to a low level prior to the addition of finely ground steel to the solution. With the pH at the low level, e.g. 2.5, the reaction of dissolved silver to precipitated silver, is facilitated. However, the pH must then be raised or neutralized, e.g. 7-8.5, in order to insure that the dissolved silver is essentially all precipitated. This material can now be safely shipped without treatment as a hazardous material and, after filtering the solids therefrom, can be safely disposed.

Abstract: A method is disclosed for polishing geothermal brines containing iron-rich silica scale and silica particles suspended therein while removing and recovering copper, silver and other precious metals dissolved therein. The method comprises passing brine having a pH just below about 5.0 through a conduit packed with a metal higher in the electromotive series than silver for a time to sufficient for substantially all of the silver and other precious metals therein to precipitate onto the packing. Preferably, the packing comprises coiled zinc-galvanized steel chicken wire mesh packed in a sufficient density to act as a filter for said suspended particles. Dissolving the packing in a suitable acid will leave a precious metal-rich residue behind for subsequent recovery. When the brine is treated this process, the useful life of injection wells used to return cooled brine back to the geothrmal field is extended by at least about 3 times as compared to that observed with untreated brine.

Abstract: The improved method and apparatus are capable of efficient removal of radioactive europium from solutions of radioactive gadolinium in a simple way. A mixture of a zinc and a graphite powder is packed into a column and both a conditioning solution corresponding to a liquid electrolyte and a sample solution containing radioactive gadolinium and europium are allowed to pass through the column.

Abstract: Heavy metals are reclaimed from a concentrated wastewater solution containing heavy metal cations and an acid by adding to the wastewater a bed of scrap aluminum in a total amount between about 160% and about 180% of the stoichiometric requirement for complete reduction of the dissolved heavy metal cations to their elemental states and adjusting the acid content of the wastewater to 5% to 20% by volume and allowing the heavy metal cations to react with the scrap aluminum to oxidize the aluminum and to reduce the heavy metal cations to their elemental states thereby producing demetallized wastewater which is neutralized with caustic to produce a treated effluent.

Abstract: A method for reducing the concentration of any undesirable metals dissolved in contaminated water, such as waste water. The method involves uniformly reacting the contaminated water with an excess amount of solid particulate calcium sulfite to insolubilize the undesirable metal ions, followed by removal thereof and of the unreacted calcium sulfite.

Abstract: A process for recovering copper from cupric ion containing aqueous solutions which comprises adding to the aqueous solution containing cupric ions an amount of reducing agent which corresponds from 0.1 to 10 moles of reducing agent per mole cupric ion, and heating the reaction mixture in the absence of oxygen in a closed vessel to a temperature of from 170.degree. to 240.degree. C., said reducing agent being one or more members of the group consisting of:(a) organic aldehydes RCHO (R=H, C.sub.1 to C.sub.5 alkyl)(b) carboxylic acids R COOH (R=H, linear or branched C.sub.1 to C.sub.5 alkyl)(c) hydroxycarboxylic acids R.sub.1 COOH (R.sub.1 =HO(CH.sub.2).sub.n, CH.sub.3 CH(OH)--, CH.sub.3 (CH.sub.2).sub.n, CH(OH)-- with n=1 to 3)(d) dicarboxylic acids R.sub.2 COOH (R.sub.2 =HOOC(CH.sub.2).sub.n with n=1 to 3)(e) amino acids R.sub.3 COOH (R.sub.3 =CH.sub.3 (CH.sub.m CH(NH.sub.2)-- (CH.sub.3).sub.2 (CH).sub.m CH(NH.sub.2 -- with m=1 to 3, CH.sub.3.CH(OH)(NH.sub.2), HOO C.CH(NH.sub.2).(CH.sub.2).sub.

Abstract: An aqueous solution for removing metals from waste water contains sodium borohydride, sodium aluminate and sodium hydroxide.

Abstract: A method for removing iron(III), copper(II), zinc(I) and nickel(II) from an effluent containing chelant (EDTA, DEPA, HOEDTA) comprising treating the effluent with a soluble calcium compound (e.g., Ca(OH).sub.2) CaCl.sub.2, Ca(NO.sub.3).sub.2) in a molar equivalent to the chelant in combination with a monovalent hydroxide to a pH greater than 12.4 and then adding an effective amount of a dialkyldithiocarbamate (e.g.; sodium-N,N-diethyldithiocarbamate) to precipitate the metal hydroxides and nickel dialkyldithiocarbamate. Heating the solution to about 180 F. further speeds up the removal of the nickel(II). The nickel concentration of spent chelant cleaning solution can be reduced to less than 1 ppm.

Abstract: A method for waste treating metal containing solutions comprising decomposing the metal from the solution in the substantial absence of air and separating the decomposed (precipitated) metal from the solution.

Abstract: A method and system for removing toxic substances such as selenium and molybdenum from agricultural irrigation water achieves nearly 100% removal of the toxic substance economically, by a chemical reduction process. The process is particulary efficacious for removing naturally occurring selenium and molybdenum from irrigation water which has seeped through the ground and taken compounds of these metals into solution. Preferably, the drain tile water solution is first concentrated, to about 30% dissolved solids. This may be economically accomplished by on site evaporation in an open pond which is impermeable to seepage. Next the concentrated brine solution 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. Wettable sulfur is added to the slurry to greatly improve the effectiveness of the iron in reducing the solution. The slurry is constantly agitated.

Abstract: The present invention relates to a process for removing radioactive ruthenium from an aqueous solution, comprising oxidizing the ruthenium in the aqueous solution of ruthenium tetroxide, extracting the resulting ruthenium tetroxide with a halogen-free aliphatic or alicyclic hydrocarbon solvent, allowing the ruthenium tetroxide to be reduced in the solvent, and separating the precipitated solid ruthenium dioxide.

Abstract: A process is described which improves the life of a silver recovery unit which employs finely divided iron and a minor amounts of a copper or cadmium salt therein by raising the pH of waste acidic photographic processing stream containing silver to be recovered. This pH increase may be accomplished using waste developer stream. An additional use of a chelating agent has been found to be beneficial.

Abstract: Disclosed is a method for treating a photographic processing waste solution comprising concentrating the photographic processing waste solution containing at least thiosulfate ions, characterized in that there is provided at least one part selected from (i) to (v) shown below:(i) a part for adding sulfite ions or a compound capable of releasing sulfite ions into the photographic processing waste solution at the time or before heating of the photographic processing waste solution;(ii) a part for contact evaporated gas with a catalyst having a metal of the following (a) to (d) or a compound thereof carried thereon:(a) at least one selected from the group VIII elements consisting of iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium and platinum,(b) copper,(c) zinc,(d) manganese;(iii) a part for permitting a water-soluble polymer to exist;(iv) a part for permitting an oxidizing agent capable of oxidizing thiosulfate ions to exist; and(v) a part for adding a pH controlling agent into the photogr

Abstract: Methods of and apparatus for recovering silver and other metals from solutions containing compounds of those metals. The solution being treated is pumped upwardly under pressure and at a constant rate through a reaction mass or medium to promote ion exchange reactions between the metal of interest in the solution and the material making up the reaction mass and thereby precipitate the metal of interest from the solution being treated.

Abstract: A method of selectively removing selenium ions from an aequeous solution containing selenium ions comprises contacting the solution with an amount of ferrous ion effective to reduce the selenium ions to elemental selenium. The contacting is preferably conducted at a pH of about 9 and the ferrous ions are preferably provided in situ in the form of ferrous hydroxide. The method may further comprise removing ferric oxides to which the ferrous ions are oxidized, these ferric oxides containing the elemental selenium produced by the reduction of the selenium ions, and separating the ferric oxides from the elemental selenium by adding a strong acid thereto.

Abstract: A waste treatment method for metal hydroxide electroplating sludges. Metal hydroxide sludges from the treatment of electroplating waste waters are rendered environmentally safe. The sludges are first dewatered and heated to a temperature sufficient to cause the metal hydroxides to convert to metal oxides. Predetermined quantities of silica and soda, or sources thereof, are mixed with the metal oxides. The mixture is further heated to a temperature sufficient to cause fusion of the mixture and form a slag-like composition having the metal oxides in chemical solution. The slag-like composition is then cooled to ambient temperature. The structure of the cooled slag-like composition is predominantly crystalline, having the metal oxides in solid solution in either a precipitate phase or a silicate matrix. The slag-like composition is resistant to corrosion even in an acidic environment.

Abstract: This invention relates to a process for reducing the concentration of heavy metal ions in an aqueous waste solution, comprising the steps of:(a) contacting the aqueous waste solution with a mixed culture of Citrobacter freundii and a dissimulatory sulfate reducer, in the presence of nutrient sufficient to satisfy the nutritional requirements of the mixed culture, for a time sufficient to produce sulfide ions from a sulfide-ion precursor in the aqueous waste solution or nutrient and to precipitate the heavy metal ions in the form of corresponding sulfides and(b) removing the thus-precipitated sulfides from the waste solution.

Abstract: The present invention relates to a method for treating lakes with selenium with the intention of lowering the mercury content of fish, and is characterized by supplying to the lake selenium in the form of a selenium salt incorporated in a carrier material capable of dispensing selenium to the surrounding water substantially continuously and in a controlled manner. The carrier material is preferably a rubber-based or silicon-based and biologically degradable material. There is preferably maintained an effective selenium level of beneath 10 .mu.g.

Abstract: A process is provided for the treatment of high-boiling, solids- and copper-containing residues produced during organochlorosilane synthesis. The process comprises hydrolyzing, oxidizing the hydrolyzed residues with a free oxygen-containing gas and separating-out a copper-containing solution.

Abstract: A method is disclosed for controlling the deposition of metal-containing scales, such as iron silicate scale, from a hot, aqueous, geothermal brine or the like, without substantial corrosion of brine handling equipment. The brine is contacted with (1) an amount of an acid sufficient to reduce the pH of the brine between 0.1 and 0.5 unit and (2) a greater than stoichiometric amount of a reducing agent for reducing trivalent iron and manganese cations in a high temperature brine solution to divalent ions. An overall decrease in scale deposition, especially of iron silicate scale, is achieved while a silver-rich scale can be recovered from silver-containing brines.

Abstract: Process for recovery of silver from spent, waste acidic silver halide photographic processing fluid, e.g., fixer solution, comprising passing the fluid through finely divided iron, e.g., steel wool, contained in a vessel in the presence of a metal salt of copper or cadmium, e.g., copper(II)sulfate, copper chloride dihydrate, cadmium sulfate, etc. The ratio of iron to metal salt is 25 to 1 to 4 to 1. An apparatus for recovery of silver is also described.

Abstract: Free cyanide-containing wastewater is treated to destroy the free cyanide content thereof by the step of treating said water with sulfur in the form of polysulfide in an integrated process wherein thiocyanate is also eliminated to produce a non-hazardous wastewater effluent and treating the wastewater in a second step with cultures of bacteria of the genus Thiobacillus in combination with nitrifying bacteria which oxidize ammonia to nitrite and nitrite to nitrate. The first step is preferably carried out in the presence of added metallic zinc.

Abstract: A heavy metal can be removed from waste water, in which the metal is contained as ions, by adding to the waste water a metal scavenger together with at least one of sodium monosulfide, sodium polysulfides and sodium hydrogensulfide to form a metal ion containing floc. The resulting floc is then removed from the waste water by filtration. The metal scavenger contains at least one carbodithio group and/or at least one carbodithioate salt group as N-substituents per molecule.

Abstract: Redissolution and/or reoxidation of metals precipitated by chemical reduction from aqueous solutions can be prevented by adding a bicyclic, aromatic, organonitrogen compound to the solution in a amount insufficient to cause precipitation of said metal but sufficient to prevent the redissolution and reoxidation of the precipitate. The compounds added can be selected from benzotriazoles, benzothiazols and benzimidazoles.

Abstract: A method for treating a heavy metal-containing liquid, such as a wastewater stream, oil for recycling, or other metal-bearing liquid, with a trithiocarbonate, particularly an alkali metal trithiocarbonate, such as sodium trithiocarbonate, to precipitate the metals as insoluble sulfides. The precipitated metal sulfides are recovered as a low volume sludge, which can be processed through standard metallurgical techniques to yield the metals in economically useful forms. Among the most unexpected results produced by this method is the lowering of the selenium content in a naturally occurring body of water from 1.0 ppm to 0.0015 ppm.

Abstract: In a process for reduction or oxidation of materials in aqueous solution by assing a reagent gas through a finely porous catalyst layer into the solution, bodies of electrically conducting material which in the aggregate have a large surface are brought into electrically conducting connection with the catalyst layer on its side facing the solution in order to increase the rate of conversion of the dissolved material. The conducting bodies are distributed in the solution at least in the region of the catalyst layer and increase the effective surface for the conversion of the dissolved material. The invention is particularly useful in connection with catalyst layers provided with an electrically conducting protective cover through which gas and solution may pass on the side of the catalyst layer facing the solution as disclosed in a related application of the same inventors Ser. No. 500,941 filed June 3, 1983.

Abstract: A process for the removal and recovery of mercury and, if desired, other heavy metals from incinerator waste water produced by washing waste gases from incinerators, which comprises adding to the waste water a reducing agent or a combination of oxidizing and reducing agents, subjecting the thus added waste water to stripping treatment in the presence of ferrous ion to obtain a mercury vapor-containing gas and simultaneously form spinel type crystalline compounds and then cooling said gas to separate and recover the mercury. If desired, said spinel type crystalline compounds are also removed from the mercury-free waste water.

Abstract: Hydrocarbons containing PCB are blended with metallic sodium at a temperature of about 130.degree. C. and thereafter the mixture is separated into its components one of which is a hydrocarbon containing less than about 2 ppm of PCB. When the 1254 arachlor is the predominant species of the PCB, metallic sodium having a maximum dimension of about 1/4 inch to about 1/2 inch is blended with the heated hydrocarbon. When the 1254 arachlor is not the predominant species of the PCB, metallic sodium having a maximum dimension of about 20 microns to about 50 microns is blended.

Abstract: A process for removing or decreasing the amount of color in a solution such as an oil well brine by adding hydroxylamine or hydrazine. The hydroxylamine or hydrazine may be added in any form such as the pure compound, a salt, the hydrate or the like.

Abstract: Effluents from cyanidation operations are treated by contacting the effluent with powdered sulphur and iron to reduce the base metal content and cyanide ion content of the effluents.

Abstract: The invention provides an improvement in the disposal of a waste water coining iron-cyanide complexes including ferricyanides by the reduction of the ferricyanide ions into ferrocyanide in the presence of a zinc salt to precipitate the ferrocyanide ions in the form of zinc ferrocyanide. The improvement comprises the use of a sulfite, e.g. sodium sulfite, and a thiosulfate, e.g. sodium thiosulfate, in combination as the reducing agent whereby the reduction of the ferricyanide ions is complete within a relatively short time without being affected by the atmospheric oxygen or other factors.

Abstract: A method and apparatus for extending the useful life of an aqueous acid chloride solution that serves as a protective bath for an activator dip bath such as used in electroless copper plating. Means are provided for recirculating the acidic chloride solution over metallic tin to precipitate copper ions from the solution. The precipitated copper is filtered from the solution to extend its useful life.

Abstract: A process is provided for the waste treatment of metal plating solutions. One embodiment of the process comprises removal of the metal values contained in solution and inactivation or destruction of the complexing agent's ability to complex heavy metals. A second embodiment comprises inactivation or destruction of the complexing agent as a first step, formation of a sludge if not formed by inactivation of the complexing agent and sludge removal. Either embodiment permits direct discharge of spent plating solutions into the environment without violation of federal or municipal regulation.

Abstract: A method for removing the excess sodium and byproducts of reaction which occur during the destruction of PCBs from oil. A predetermined quantity of water is mixed with the decontaminated oil and the byproducts, which include sodium chloride and polyphenyl polymer, to form sodium chloride and sodium hydroxide. Centrifuging removes most of the oil from the remaining aqueous mixture which then is agitated and treated with carbon dioxide gas to form less hazardous sodium carbonate and sodium bicarbonate. Any excess carbon dioxide gas is vented to the atmosphere and the sodium carbonate and sodium bicarbonate is collected into containers for disposal. Small amounts of oil remaining in the aqueous waste mixture that is discharged from the centrifuge is decanted from the remaining material in a waste separator due to its lighter specific gravity. A pump intermittently injects waste from the waste separator into a converter where it reacts with the carbon dioxide gas.

Abstract: A process for reducing the concentration of selenium ions in the Se(VI) oxidation state in an aqueous solution. The aqueous solution is admixed with a quantity of metallic iron. The iron reduces the selenium ions from the Se(VI) oxidation state to a lower oxidation state and then dissolves in the aqueous solution. If the pH level of the aqueous solution is above about 2.3, the selenium ions are reduced to at least the Se(IV) oxidation state and the dissolved metallic iron hydrolyses to form an iron hydroxide that precipitates. The precipitated material is separated from the aqueous solution to provide a solution having a lower concentration of selenium ions. If the pH level of the aqueous solution is below about 2.3, no iron hydrolysis is observed to occur. At least a portion of the selenium in the Se(VI) oxidation state is believed to be reduced to the elemental state. The elemental selenium then is separated from the aqueous solution to provide a solution having a lower concentration of selenium ions.

Abstract: Trihalomethanes (THM's) in water, particularly in drinking water, are substantially reduced by treatment of the water with small amounts, i.e., below about 50 ppm, of sulfite ion supplied by sodium metabisulfite or sulfur dioxide. The addition to the water of the sodium metabisulfite alters the structure of the THM's precursor and lowering the chlorine demand. The sulfite ion may be introduced prior to chlorination, or at an intermediate stage of the chlorination, or in adjunct with the chlorination which permits the use of substantially reduced amounts of chlorination.

Abstract: A continuous method for destroying polyhalogenated biphenyls by reacting a solution of the biphenyls in an inert liquid at a concentration of from about 1% to about 5% by weight with a dispersion of sodium in a hydrocarbon oil.

Abstract: A field method for removing polychlorinated biphenyls (PCB's) and similar halogenated aromatic hydrocarbons from silicone based oils and hydrocarbon fluids such as transformer oils contaminated with them by contacting the contaminated oil with a hydrocarbon dispersion of sodium, reacting the mixture of oil and sodium dispersion at a temperature above about 75.degree. C., and passing the treated oil through a filter medium or other separating means to remove particulate and other contaminating material.

Abstract: A method of removing ruthenium contamination from a radioactive liquid effluent, consisting in adding to said liquid effluent a reducing agent and copper ions, to form, in said effluent, a cuprous oxide precipitate on which the ruthenium is fixed, and subsequently separating the precipitate thus formed from the effluent, and an apparatus for performing this method.

Abstract: Process for the treatment of decontamination effluents, more particularly the components of nuclear reactors, of the type containing in solution permanganate, phosphate and sulphate ions and active manganese, chrome and cobalt ions, wherein it comprises the successive stages of reducing the permanganate ions by adding hydrogen peroxide, alkalization to a pH equal to or above 12, separation of the precipitate formed and final acidification of the residual liquid phase to bring its pH to a value compatible with discharge into the environment.The invention also relates to an apparatus for performing the above process.

Abstract: A process is provided for the waste treatment of metal plating solutions One embodiment of the process comprises removal of the metal values contained in solution and inactivation or destruction of the complexing agent's ability to complex heavy metals. A second embodiment comprises inactivation or destruction of the complexing agent as a first step, formation of a sludge if not formed by inactivation of the complexing agent and sludge removal. Either embodiment permits direct discharge of spent plating solutions into the environment without violation of federal or municipal regulation.

Abstract: A process for the removal of mercury and mercury compounds from aqueous solutions and, in particular, industrial waste liquors, by reduction and filtration, wherein after reduction, the liquors are cleared by letting the mercury particles and dirt particles flow into a settling basin. Subsequently, the supernatant aqueous solution from the settling basin is subjected to filtration in a deep filter with a filtering agent having a grain size of 0.02 mm to 2 mm and preferably 0.04 mm to 0.6 mm, whereupon the mercury is returned by reverse rinsing into the settling basin from the filter and is separated in the settling basin.

Abstract: An admixture of waste (oil-well) drill cuttings, drilling fluid and by-products of rotary drilling are separated into good-quality water and high-density solids by chemical and mechanical means in original earthen-mud storage and/or reserve pits. The treatment produces two useful benefits: (1) good-quality water (useful for agriculture or for drilling a new well) is recovered, and (2) resulting concentrated solids are of such a high density that the land area occupied by and containing such dewatered solids can be immediately leveled and restored to the same use it had before the well was drilled. The effect is a reduction in energy of at least 75 to 85 percent over the present method of hauling whole mud off by trucks to a commercial waste-disposal site.

Abstract: Mercury can be recovered from nitric acid-containing fluids by reacting the fluid with aluminum metal to produce mercury metal, and then quenching the reactivity of the nitric acid prior to nitration of the mercury metal.