Abstract: A method of manufacturing a water barrier fabric, in flexible or rigid form, and articles manufactured thereby, formed by dispersing a water-absorbent material, in powdered or granular form, among a mass of fibers during the formation of a loose mat of said fibers, to homogeneously disperse the powdered or granular water-absorbent material above, below and on each side of the fibers forming the mat, and thereafter densifying and structurally consolidating the mat, to secure the fibers in position surrounding and entrapping the water-absorbent material, such as by sewing, quilting, needle punching or otherwise bonding the fibers into a consolidated, structurally secure fabric at least partially filled with the powdered or granular water-absorbent material. In a preferred embodiment, one, or both, major surfaces of the fabric is coated with a water-insoluble adhesive to substantially increase the tensile strength of the fabric and to prevent shifting of fibers when installed on sloping surfaces.

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: A method for removing metal compounds from waste water comprising the steps of adjusting the pH of the water to from 5 to 12 and preferably 6 to 9; aerating the waste water; adding a flocculating agent to the water and allowing floccules including metal compounds to form; and separating said floccules including metal compounds from the water. An apparatus for carrying out this method is also disclosed.

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 process for the separation of radioactive iodine compounds by precipitation is provided. This process comprises adding 0.1 to 3 parts by weight of a reducing agent and an effective amount of silver nitrate to 100 parts by weight of a liquid waste containing radioactive iodine compounds while keeping the liquid waste at a temperature ranging from 20.degree. to 80.degree.C., and stirring the obtained mixture for 0.5 to 72 hours to precipitate the radioactive iodine compounds. Silver nitrate is preferably used in a molar concentration which is 1 to 4 times that of radioactive iodine molecules contained in the liquid waste. By this process, iodates which could not be precipitated by conventional methods can be effectively precipitated and separated to thereby reduce the amount of radioactive iodine discharged to the environment.

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: A multi-layer article of manufacture includes an intermediate layer of a water-swellable colloidal clay, such as bentonite, sandwiched between two layers of flexible sheet or fabric material wherein the two flexible layers of sheet or fabric material are structurally interconnected through the intermediate clay layer, such as by needle punching, after lubrication of the clay with a liquid, such as water, to interconnect fibers of one fabric layer to the other fabric layer at spaced locations over essentially the entire inner surface areas of both sheet or fabric material layers.

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: 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 method of treating solid waste in soil or solid disposed waste containing unacceptable levels of leachable metals, such as lead, cadmium, arsenic, zinc, copper and chromium, includes mixing the solid waste or soil in place with a phosphate source or a carbonate source or ferrous sulfate. After the solid waste and the additive are mixed, if needed an additional pH controlling agent is mixed into the soil or waste and additive. After the solid waste and additive and pH controlling agent are mixed under conditions which support reaction between the additive, pH controlling agent and metals, the metals will be converted to non-leachable forms which are relatively stable under normal environmental conditions.

Abstract: A multi-layer article of manufacture includes an intermediate layer of a water-swellable colloidal clay, such as bentonite, sandwiched between two layers of flexible sheet or fabric material wherein the two flexible layers of sheet or fabric material are structurally interconnected through the intermediate clay layer, such as by needle punching, after lubrication of the clay with a liquid, such as water, to interconnect fibers of one fabric layer to the other fabric layer at spaced locations over essentially the entire inner surface areas of both sheet or fabric material layers.

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: An agent for the treatment of water containing dissolved aluminum comprises a particulate alkali metal or quaternary ammonium silicate, the particles having a coating of a water-insoluble silicate over at least a part of their surface, and a process of treating water which comprises dissolving the agent in the water.

Abstract: An improved method of decontaminating a solvent which contains mustard. The mprovement consists essentially of using polydivinylbenzene to absorb the said mustard.

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: An absorption process of using polydivinylbenzene to remove nerve agents h as GD from a conventional solvent such as chlorofluorocarbon which itself is used to decontaminate a surface such as armament.

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: Disclosed is a method for treating in a continuous manner an aqueous solution containing ions of a given type in order to remove these ions from the solution. According to this method, the aqueous solution containing the ions to be removed is first neutralized if it is acidic. Then, it is contacted with a metal salt which is sparingly soluble in water and has a very strong affinity to react with the ions to be removed to form therewith another salt which is insoluble in water, for a period of time sufficient to allow this other salt to be formed and precipitate. This method is very efficient and can be used, by way of example, for removing chromium ions from an industrial waste water, using barium carbonate as sparingly soluble salt.

Abstract: An improved process for removal of soluble contaminants from wastewater is disclosed which provides significantly enhanced contaminant removal and overall process efficiencies. The improved contaminant removal process is especially suitable for treatment of industrial effluents having high levels of dissolved cyanide and arsenic contaminants. Wastewater undergoes multiple stage sludge treatment, wherein sludge is mixed with wastewater sequentially in a plurality of discrete reaction stages for relatively short retention times. Reaction conditions which promote chemical and/or physical reaction of soluble contaminants with sludge are maintained, and liquid/solids separation is effected after each sludge treatment stage. Oxidizing agent is preferably mixed with the wastewater prior to multiple stage sludge treatment to change the oxidation state of inorganic contaminants and remove cyanide contaminants from solution.

Abstract: A method and apparatus for cleansing contaminated soil (11), the apparatus includes an extraction vessel (12) into which contaminated soil (11) is delivered together with a solvent. A slurry is produced which is delivered to a settler (18) which produces a settler underflow and contaminated solvent. The settler (18) underflow is delivered to a drier (23). The contaminated solvent passes through a filter (20) which produces a filter cake also delivered to the drier (23). The contaminated solvent passes through a distillation column (28) and is subsequently delivered to a plasma gun (35) whereat the contaminants are oxidized.

Abstract: A polydivinylbenezene macroreticular strong acid resin can effectively detaminate solutions containing organophosphorus chemical warfare agents such as o-ethyl S-(2-diisopropylaminoethyl) methylphosphonothiolate (VX).

Abstract: A system for removing hazardous contaminants such as radon gas and volatile synthetic organic chemicals from domestic water supplies includes a perforated, horizontally-oriented tray which is baffled to define a curved (e.g., serpentine, spiral) liquid flow path. Contaminated water is distributed upon a portion of the tray and flows as directed by the baffles to a downcomer and into a storage tank. Air is blown into the storage tank, which is located below the perforated tray, and up through the perforations. The forced air causes the water flowing across the tray to froth, and evaporates the contaminants out of the frothing water. The forced air, carrying the volatilized contaminants, is then vented outside the home.

Abstract: A method is provided for oxidizing arsenic in an arsenic-containing solution. The method comprises contacting the solution containing arsenic in a +3 oxidation state with an amount of a specific type of oxidizing agent, i.e., an agent containing at least one ##STR1## wherein X is a halogen to effect substantially complete oxidation of the arsenic to the +5 oxidation state. The amount of oxidizing agent used is substantially less than that which would theoretically be required. In accordance with a particularly preferred embodiment, the oxidized arsenic is reacted with a metal to form a substantially water-insoluble precipitate, preferably an iron or calcium arsenate.

Abstract: A process for preparing hydrogen fluoride involving treating anhydrous hydrogen fluoride containing primarily trivalent arsenic impurities with an effective amount of chromium (VI) oxide (i.e., CrO.sub.3) and oxygen such as to oxidize substantially all of the trivalent arsenic to pentavalent arsenic (i.e., As.sup.+3 .fwdarw.As.sup.+5) followed by separation and recovery (e.g., by distillation) of purified anhydrous hydrogen fluoride.

Abstract: A method of disposing of wastes containing heavy metal compounds by neutralizing the wastes, oxidizing the neutralized wastes, then solidifying the oxidized wastes using conventional mineral binding agents such as Portland cement. This method is of particular interest in treating arsenic sulfide containing aqueous sludges produced in the manufacture of phosphoric acid.

Abstract: The invention provides a method for accelerating the removal and recovery of selenium from aqueous solutions, such as agricultural irrigation drainage streams or mine waste waters by the bioreduction of Se(VI) to Se(IV) species by using Clostridium soil bacteria together with a rapid exchange reaction which occurs between the aqueous selenium species selenous acid (H.sub.2 SeO.sub.3) and pyrite (FeS.sub.2) to remove all forms of selenium from the aqueous solution. The exchange reaction product FeS.Se may be treated with dilute mineral acid such as sulfurous acid to generate hydrogen selenide (H.sub.2 Se), which is burned in air to yield free selenium. The free selenium recovered is available for use in the electronics, photocopying equipment and other industries. A reusable bacteria-containing soil and pyrite filter apparatus for installation in drainage canals and other conduits is additionally provided to facilitate the removal of aqueous selenium pollutants.

Abstract: N,N'-dihalo-2-imidazolidinones are described as decontaminants for toxic chemical agents such as the sulfur mustards. Decontamination is effected by contacting the toxic chemical agent with a decontaminating amount of the N,N'-dihalo-2-imidazolidinone, e.g., 1,3-dichloro-4,4,5,5-tetramethyl-2-imidazolidinone.

Abstract: This invention is directed to a process for the chemical stabilization of heavy metal bearing dusts and sludges. A preferred use for such process is the treatment of dust from an electric arc furnace (EAF). In the production of steel by the electric arc furnace process, a by-product thereof is the generation of EAF dust. Such dust, by virtue of the presence of such elements as cadmium, hexavalent chromium and lead, is classified as hazardous waste by U.S. Environmental Protection Agency (EPA). The present invention is directed to a process for the chemical stabilization of the inorganic EAF dust to render the hazardous constituents thereof virtually immobile. Such process is based on the pozzolanic reaction of materials containing anhydrous alumino-silicates which, in the presence of lime, water and chemicals, adsorb and/or physically entrap the heavy metals present in EAF dust into a calcium-alumino-silicate matrix.

Abstract: Dissolved selenium is removed from water by treatment in a reactor containing microbial biomass to cause the hexavalent selenium to be converted to forms of selenium which can be readily removed from the water, and causing or allowing the removable forms of selenium to be removed from the water. Examples of removable forms of selenium include volatile organic selenium compounds, volatile inorganic selenium compounds, elemental selenium, entrainable organically-complexed selenium compounds, entrainable tetravalent selenium compounds, and entrainable bivalent selenium compounds. The volatile selenium compounds can be removed and recovered as a gas, while the entrainable forms of selenium can be entrained by larger particles and separated off, for example by filtration.

Abstract: A process of treating effluent from a pulp or paper-making operation to decolorize the effluent is provided in which a white-rot fungus is germinated and grown and is then induced into a secondary metabolic state. The white-rot fungus is then immersed in the effluent where the fungus' active ligninolytic system decolorizes the effluent. The rate of fungal activity and the active lifetime of the fungus is increased by the addition to the effluent of at least one member of the class consisting of nutrient nitrogen, nutrient minerals, and a detergent.

Abstract: Filter cake waste media from a phosphoric acid purification process containing contaminating amounts of arsenic is treated in the process of this invention to remove the arsenic therefrom and to render the filter media suitable for reuse. The process of the invention comprises separating the arsenic contaminant from the filter material by treating the material with sufficient amount of a base, such as soda ash, to dissolve the contaminating arsenic compounds into solution and separating and recovering the filter media from the arsenic-containing solution. The separated arsenic can be recovered by reprecipitation utilizing an acid and a source of soluble sulfide ions.

Abstract: A method for treating liquid and semi-liquid wastes to render them fit for ultimate disposal, by first determining the ionic charge of the waste counter ions. An appropriate suspension of emulsified asphalt particles is then selected having an opposite particle charge to the ionic charge of the waste counter ions. The waste is then mixed with the selected suspension of emulsified asphalt particles at ambient temperature in an amount sufficient to react with the waste counter ions and coalesce into a hydrophobic mass.

Abstract: An improved process for treating aqueous effluents and purge streams to selectively remove polluting elements such as iron, copper, lead and mercury therefrom is described. The procedure comprises contacting the effluent with a poly(dithiocarbamate) chelating agent whereby the polluting elements are absorbed. The resin is extracted with an acidic aqueous solution having a pH of from about 4 to about 6; and removing the resin. When this is done, the residual content of these polluting elements in the effluent is reduced to a level below EPA required levels so that the effluent can safely be discharged into the surrounding ecosystem. The poly(dithiocarbamate) resin containing the polluting elements can be disposed of, for example, by being deposited in an unsecured landfill.

Abstract: The invention relates to a method for purifying aqueous solutions containing at least one impurity element from the group consisting of arsenic, phosphorus, mercury and other heavy metals and solid matter by precipitation in at least two stages with the aid of precipitation reagents possessing ions capable of forming not-readily dissolved hydroxide precipitate. In accordance with the invention the main part of the precipitation reagent is introduced to the stage or stages following the first stage. The impurity element-containing precipitate formed in the aqueous solution subsequent to adding the reagent is separated therefrom substantially completely, and is returned so as to be present in the first precipitation stage, while that part of the solution which has been freed from precipitate in a later stage is withdrawn from the system. Substantially all the impurity element amount present in the ingoing aqueous solution are separated therefrom in the form of a sludge prior to the second precipitation stage.

Abstract: Aqueous and organic fluids which contain arsenic are contacted with spent oil shale from an oil shale retorting operation and separated therefrom, yielding a fluid of reduced arsenic content. In one embodiment, shale oil is placed in contact with spent oil shale under conditions of elevated temperature and pressure to reduce the arsenic content of the oil.

Abstract: A method for treating aqueous liquid and semi-liquid wastes by solidification comprising the steps of mixing with the waste a dry water-reactive solidification agent comprising cement, a dry water absorbent material, and a powdered alkali metal silicate in a quantity sufficient to convert the mixture into a chemically and physically stable solid end product substantially insoluble in water and which contains no substantially free-standing water, and allowing the mixture to set to a sedentary mass. Additive agents such as surfactants, fixatives, waterproofing agents, coloring agents, and the like are also disclosed as assisting in the solidification reaction by reacting with certain constituents in the waste.

Abstract: Various metals including cobalt nickel and copper can be recovered from a roasted ground ore or waste and particularly from tailings of a pyritic gold ore by leaching with sulphuric acid, oxidizing the separated leach liquor, filtering and partially neutralizing the liquor. In an improved process, the oxidation is effected with peroxomonosulphuric acid and the neutralization with a 60:40 to 40:60 mixture of calcium and sodium hydroxide/oxide. By so doing, it is possible to minimize the number of process stages by elimination of either or both solid/liquid separations and to combine the leach and oxidation stage, or to improve the separation of metals from impurities.