Abstract: Pulp mill bleach plant caustic extraction effluent is decolorized using a primary or other sludge from a pulp and paper mill. The sludge is acidified and mixed with the effluent. After a short incubation period, the mixture of acidified sludge and effluent is raised to at least neutral pH, causing precipitation of most of the color in the effluent. The precipitated color may then easily be separated from the liquor by any conventional clarification technique. The method avoids the consumption of large quantities of expensive reagents or high transportation costs associated with the prior art decolorization techniques used on such effluent.

Abstract: A powder of a slag formed at the time of manufacturing steel is used to remove heavy metals contained in waste water. After the use the slag may be heated to recover the heavy metals adsorbed thereby or the used slag may be formed into solid blocks, ballast or aggregate by admixing with Portland cement or alumina cement.

Abstract: A process for obtaining calcium fluoride from the pond water of phosphoric acid plants and recycling the high phosphate defluorinated water to the pond is disclosed. Sufficient calcium carbonate is added to a solution having a pH of about 0.8, containing about 1% fluoride, 1% phosphate and less than 0.4% sulfate, to raise the pH thereof to 2-3, whereby calcium fluoride is precipitated as a major component, calcium phosphates and calcium sulfates are precipitated as minor components. The calcium fluoride precipitate obtained is washed with raw pond water to reduce the phosphate content and with ammonium carbonate solution to reduce the sulfate content. In this manner an industrially useful fluorspar is obtained. The low fluoride supernatant liquid is then mixed with sufficient raw pond water to bring the pH into the range 1.5-2.0 and the resulting suspension is then held in a lagoon for 5-21 days to permit separation of silica.

Abstract: A contaminated carrier liquid in a chamber is cleaned by adding thereto oil particles having a charge and a composition that induces the formation of an hydroxide floc to form an intermediate filtering layer in the chamber. A top clean oil layer is recovered and a bottom clean aqueous layer is recovered. The intermediate layer can be treated to form a composition that can be recycled to form an hydroxide floc.

Abstract: Heavy Metals contained in industrial waste streams are removed therefrom by flocculation using a source of ferric ions and an alkaline material at a basic pH. Both the flocculated heavy metals and the coagulant chemicals are recovered by acidifying the floc to a pH of between 3.2 and 3.7. This liberates the heavy metals back into solution but does not destroy the floc particles. After separation and removal of the concentrated heavy metal solution, the floc is further acidified to completely dissolve it. This dissolved ferric ion containing solution may then be reused to treat succeeding portions of heavy metal containing waste streams. The concentrated heavy metals solution may also be recycled or the metals contained therein recovered for reuse or disposed of in an acceptable manner.

Abstract: A process for extracting metal ions from a water insoluble metal base or salt dispersed in an aqueous solution using liquid ion exchange is described. The liquid ion exchange extractant is an alkyl phosphoric acid or acid phosphate (APA) which is dissolved in a water immiscible organic solvent. In contrast to prior art processes where the metal ion is dissolved in an aqueous solution, the insoluble metal base or salt is one which is reactive from an aqueous solution with the APA to replace one of the acid hydrogens to form an alkyl phosphate metal salt (APS) in the organic solvent. The metal ion can be recovered from the APS in the organic solvent by stripping with an aqueous acidic solution so that the metal ion is removed from the APS to form a metal salt in the aqueous acidic solution and the APA in the organic solvent is regenerated for reuse.

Abstract: A method for the treatment of an aqueous effluent slime derived from a tar sand extraction process is disclosed. The effluent slime pH is adjusted to an acidic pH and treated with an anionic surface active agent to create flocculation of solid asphaltic material entrained within the slime. A solvent solution comprising chlorinated hydrocarbon and a solvent therefor is added so that upon centrifuging of the treated slime three physical layers of material comprising (1) water; (2) asphaltics in the solvent solution and (3) clay are formed.

Abstract: A particulate coagulant/adsorbent for removing suspended impurities and colored substances from water by coagulation comprises a finely divided particulate mineral or clay material, the individual particles of which have been treated to produce a thin hydroxylated surface layer haivng a positive zeta potential at the adsorption pH.A process and an apparatus for water treatment utilizing the coagulant/adsorbent and providing for regeneration and recycling thereof are also described.

Abstract: Disclosed is a process for the treatment of water so as to produce water of high purity, such as potable water. The process also entails the treatment of water which may have received prior water treatment, and comprises adding an effective amount of chemical flocculant to the feed water and subjecting said water to flocculation; passing the flocculated water to a clarifier where suspended solids are separated from the partially purified water; adding about 1 to about 100 parts powdered activated carbon per million parts of water from the clarifier; contacting the water with said carbon in a reaction zone so as to achieve substantial reduction of contaminants in the water; separating the activated carbon from the purified water; and recycling a portion of the separated activated carbon to the clarifier effluent.

Abstract: A method of pretreating raw water, for instance sea water, which is intended for supplying reverse osmosis units. An aqueous solution of acid salt and acid with the same anions is mixed with the raw water, whereby the most advantageous pH value is adjusted for the reverse osmosis, and whereby the acid salt is converted into the corresponding hydroxide. After possible addition of flocking or flaking additives, the resulting hydroxide flakes are separated, in a strongly concentrated form, by way of a centrifuge, particularly a plate or disc centrifuge, and together with fresh metal salt, are again brought into solution as a salt by means of the previously mentioned acid and, after mechanical purification in a second centrifuge, likewise particularly a plate or disc centrifuge, are again supplied to the raw water. The pretreated raw water leaves under pressure from the separator through which it flows and, alternatively, a chemical reducing agent may be added to this departing water flow.

Abstract: The invention relates to a method of treating in particular polluting materials such as hydrocarbons. Said materials are processed with at least one basic product such as hydraulic, natural organic or synthetic binder and in particular the calcium sulphate semi-hydrates showing qualities required for a quick setting, hardening, sequestration and retention. More particularly, the basic products used are calcium sulphate semi-hydrates in the form ALPHA. Said basic products may be also used for the processing of residual sludges or waste waters.

Abstract: Fine coals suspended in a coal flotation froth are more efficiently filtered when the flotation froth is subjected to a thickening operation prior to filtration. The thickening operation is accomplished by the use of a clarifier or thickener.

Abstract: A method and apparatus for treating a water containing waste such as industrial sludges and animal excrements. The method comprises a first step of mixing the waste with an alkaline earth metal oxide such as calcium oxide to obtain a preliminarily dried mixture and a second step of further drying and granulation of the mixture. The apparatus comprises a reactor for a mixture of the waste and an alkaline earth metal oxide, a drying kiln equipped with a stirrer means, a furnace surrounding the drying kiln and an exhaust collector means adapted to collect an exhaust gas from the reactor and drying kiln and transfer it to the furnace. Fuel consumption is saved by utilization of the exothermic reaction of an alkaline earth metal oxide with water contained in the waste. The waste may be converted by the method to usable products such as fertilizers, cement materials or cement additives.