An industrial waste salt resourceful treatment method comprises the following steps: the industrial waste salt is sequentially subject to dissolving, chemical pre-purification, deep purification, organic matter concentration reduction, adsorption and oxidation decolorization and multi-effect evaporative crystallization to respectively obtain sodium sulfate, sodium chloride and sodium nitrate crystals; the crystallization temperature of sodium sulfate is in a range of 75° C. to 85° C.; the crystallization temperature of sodium chloride is in a range of 60 to 70° C.; and the crystallization temperature of sodium nitrate is in a range of 45° C. to 55° C. An industrial waste salt resourceful treatment device is further provided.

A method is disclosed for concentrating and purifying an eluate brine and producing a purified lithium compound. An extraction eluate, rich in lithium, is directed to a nanofiltration unit or a softening process that removes sulfate and/or calcium and magnesium. Permeate from the nanofiltration unit or the effluent from the softening process is directed through an electrodialysis unit. As the lithium-rich solution moves through the electrodialysis unit, lithium, sodium and chloride ions pass from the solution through a cation-transfer membrane and an anion-transfer membrane to concentrate compartments. A dilute stream is directed through the concentrate compartments and collects the lithium, sodium and chloride ions. The electrodialysis unit also produces a product stream which contains non-ionized impurities, such as silica and/or boron. Concentrate from the electrodialysis unit is subject to a precipitation process that produces a lithium compound that is subsequently subjected to a purification process.

The invention relates to a device for drawing off liquid salt, particularly for facilities for purifying wastewater, said device comprising a heating chamber. The heating chamber comprises an inlet for introducing a salt-containing substance and is connected to an outlet for a salt melt. The outlet comprises an outlet channel and an outlet channel end, a cooling region for cooling the salt melt being provided downstream of the outlet channel end. The outlet channel is peripherally surrounded by an outlet wall at least along a section, the outlet comprising a heating element.

A process to treat water includes adding a salt-forming base to the water thereby producing saline water, or thereby forming a salt in the water which is different from a salt that the water started out with, if the water started out as saline. The saline water is treated, at a temperature T1 which is above the saturation temperature of the saline water, in a first membrane separation stage to provide clean water and a first brine, the salinity of the first brine being higher than the salinity of the saline water. The first brine is cooled to a temperature T2 to precipitate some of the salt from the first brine and the precipitated salt is separated from the first brine producing a second brine, the temperature T2 being below the temperature T1 but above the freezing temperature of the first brine. The second brine is treated at a temperature T3 above the saturation temperature of the second brine in a second membrane separation stage to provide clean water and a third brine. The salt-forming base, the temperature T1 and the temperature T2 are selected so that the salt which is formed in the saline water has a solubility in water at the temperature T1 which is at least 1.5 times the solubility of the salt in water at the temperature T2.

A wastewater treatment method includes: a soft water treatment 1 of crystallizing calcium carbonate from wastewater to remove the calcium carbonate therefrom; and an electrolysis 2 of electrolyzing some of the wastewater from which the calcium carbonate has been removed to obtain an acidic aqueous solution and an alkaline aqueous solution, wherein at least some of the alkaline aqueous solution is circulated to be used in the soft water treatment 1.

The invention relates to a method for recovering phosphorus from sludge in sewage plants, wherein: the sludge is pre-acidified under anaerobic process conditions and the pH value is then increased to a pH value <7 by adding at least one alkaline calcium-containing chemical; brushite crystals are formed by calcium ions of the chemical and are precipitated, and deposited brushite crystals are removed; and the phosphorus-reduced sludge is then supplied to a digestion process.

A system and method of treating sour water, including providing sour water having hydrosulfide ions and a carbon-containing compound to an anodic chamber of an electrolyzer vessel, converting the hydrosulfide ions into sulfate ions in the anodic chamber via an oxido half-reaction of a first oxido-reduction reaction and generating carbon dioxide in the anodic chamber via an oxido half-reaction of a second oxido-reduction reaction associated with the carbon-containing compound. The technique includes reacting the carbon dioxide with hydroxide ions in the anodic chamber to generate bicarbonate ions. The technique includes discharging an anodic chamber solution having the sulfate ions and the bicarbonate ions from the electrolyzer vessel from the anodic chamber.

A method and plant for recovering phosphate from a biomass material, the biomass material suitably being a waste activated sludge from an upstream wastewater treatment process including a biological P removal process. The method includes an anaerobic digestion stage and steps for recovering independent streams rich in PO.sub.4 and Mg, or rich in PO.sub.4 and NH.sub.4, thereby increasing the amount of P recovered and avoiding struvite formation in the anaerobic digester and accessory equipment thereof, such as pipes.

Systems and methods of performing temperature swing solvent extraction (TSSE) descaling of produced water and desalination of high-salinity brines, e.g., those having a total dissolved solids (TDS) greater than about 250,000 ppm are capable of producing descaled water products including less than about 5% weight percent TDS. The brine/produced water feedstreams and combined with a solvent having temperature-dependent water solubility at a temperature T.sub.L. Water is extracted from the feedstream into the solvent to form a water-in-solvent extract component and a raffinate component, from which a solid phase can be precipitated as more water is portioned in the solvent and basicity increases. Heating of the water-in-solvent extract component reduces the solubility of the water therein, producing a biphasic mixture of dewatered solvent and descaled water that can be separated. Because these systems and methods do not require a phase change of water, these products are achieved with significantly higher energy efficiencies when compared to evaporation-based thermal methods.

A process for the treatment of wastewater (S1) formed during the production of starches, in particular of chemically modified starches, and which contains dissolved salts and organic compounds, in which process it is proposed that the wastewater (S1) or pretreated wastewater (S1) containing substantially the dissolved salts and the organic compounds of the wastewater (S1) is subjected to a membrane separation process in which a separation of the wastewater (S1) supplied to the membrane separation process into a first volume flow (S3) with a higher concentration of dissolved salts in relation to the supplied wastewater (S1) and a second volume flow (S2) with a reduced concentration of dissolved salts in relation to the supplied wastewater (S1) is performed, wherein the first volume flow (S3) is subjected to thermal treatment for the separation of the dissolved salts and of a third volume flow (S9) which contains a fraction of the organic compounds of the wastewater (S1). By means of the invention, a process for the treatment of the wastewater (S1) from the production of modified starches with recovery of utilizable contents is provided.