A process for reducing the concentration of one or more arsenic-containing compounds in an aqueous solution comprising at least one fluoroacid, which process comprises: (i) contacting the aqueous solution with an oxidising agent to produce one or more Asv-containing compounds; and (ii) removal of precipitated arsenic-containing compounds; wherein the process comprises a step (iii) the addition of an aqueous alkali solution or slurry, which may take place after step (i) and before step (ii) or after step (ii).

A wastewater treatment equipment and a treatment method of a wastewater are provided. The wastewater treatment equipment includes: a microfiltration unit, configured to receive and filter a wastewater to obtain a solution; a membrane salt separation unit, configured to receive the solution and separate monovalent ions and multivalent ions from the solution to obtain a first solution including the monovalent ions and a second solution including the multivalent ions; a first evaporative crystallization unit, configured to crystallize the first solution to form a monovalent salt; and a second evaporative crystallization unit, configured to crystallize the second solution to form a mixed salt; the microfiltration unit is connected to the membrane salt separation unit, and the first evaporative crystallization unit and the second evaporative crystallization unit are both directly connected to the membrane salt separation unit, the wastewater treatment equipment can achieve the standard discharge of wastewater.

The invention generally relates to osmotically driven membrane systems and processes and more particularly to increased brine concentration for zero liquid discharge using osmotically driven membrane systems and processes and the related draw solute recovery techniques for the osmotically driven membrane systems and processes.

The present invention relates to a method for recovering a rare metal salt, the method including: an acid treatment step of obtaining a rare metal-containing acidic aqueous solution by bringing a material including a monovalent rare metal and a polyvalent rare metal into contact with an acidic aqueous solution; a separation step of obtaining permeated water including the monovalent rare metal and non-permeated water including the polyvalent rare metal from the rare metal-containing acidic aqueous solution by using a nanofiltration membrane satisfying the condition (1); and a concentration step of obtaining non-permeated water having a higher concentration of the monovalent rare metal and permeated water having a lower concentration of the monovalent rare metal than that of the permeated water in the separation step, by using a reverse osmosis membrane.

A method includes supplying a supersaturated brine stream having a plurality of minerals and anti-scalant from a water treatment system to a gypsum removal system disposed within a mineral removal system. The gypsum removal system includes a gypsum reactor that may receive the supersaturated brine, may deactivate the anti-scalant such that gypsum precipitates from the supersaturated brine, and may generate a gypsum slurry having a mixture of desupersaturated brine, precipitated gypsum, and the anti-scalant in solution with the desupersaturated brine. The method also includes supplying gypsum seed crystals to the gypsum reactor. The gypsum seed crystals may precipitate the gypsum from the supersaturated brine to generate the gypsum slurry. The method also includes directing a first portion of the gypsum slurry from the gypsum reactor to a gypsum settler. The gypsum settler may reactivate the anti-scalant such that the anti-scalant absorbs onto the precipitated gypsum to remove the anti-scalant from the desupersaturated brine and may generate anti-scalant-gypsum crystals and a desupersaturated overflow having at least a portion of the plurality of minerals. The method further includes generating the gypsum seed crystals supplied to the gypsum reactor using the anti-scalant-gypsum crystals.

A method of activating and dewatering sludge through application of acoustic pressure shock waves to wastewater.

A system and method for producing minerals from divalent ion-containing brine stream includes rejecting sulfate from a divalent-ion rich reject stream in a first nanofiltration seawater reverse osmosis (NF-SWRO) unit, producing solid calcium sulfate dihydrate and a magnesium-rich brine stream in a first concentration unit, concentrating the magnesium-rich brine stream to a saturation point of sodium chloride in a second concentration unit, producing solid sodium chloride and a supernatant product stream in a first crystallizing unit, produce a concentrated magnesium-rich bittern stream from the supernatant product stream in a third concentration unit, and at least one of producing hydrated magnesium chloride from the concentrated magnesium-rich bittern stream in a second crystallizing unit and producing anhydrous magnesium chloride by prilling the concentrated magnesium-rich bitterns stream under a hydrogen chloride atmosphere in a dry air process unit.

The present invention provides advanced livestock wastewater treatment systems, devices and methods for simultaneous removal of nitrate (nitrite) from treated wastewater at cathode chamber and of organics, suspended solids and malodor (caused by volatile fatty acids) from raw wastewater at anode chamber using anaerobic bioelectrochemical system (BES). The present invention provides a device comprising at least one anode chamber equipped inside with at least one anode, and at least one cathode chamber equipped inside with at least one cathode, wherein the anode chamber is attached to the cathode chamber via separator in order to transport anions or cations between the anode chamber and the cathode chamber.

A method of chemical extraction from an aqueous solution includes receiving an aqueous solution including dissolved inorganic carbon. The method also includes increasing a pH of a first portion of the aqueous solution to form a basic solution. The basic solution is then combined with a second portion of the aqueous solution to precipitate calcium salts. The calcium salts are then collected.

A method of making building materials from an aqueous solution includes receiving the aqueous solution with dissolved ions and increasing a pH of the aqueous solution so the dissolved ions precipitate from the aqueous solution as salt. The method also includes collecting the salt precipitated from the aqueous solution and forming the building materials from the salt.