# US 8,465,642 B2 · Method and apparatus for separating impurities from a liquid stream by electrically generated gas bubbles > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,465,642 B2 - Document ID: US8465642B2 - Status: Granted - Kind: B2 - Application number: 12/113,443 - Filed: 2008-05-01 - Published: 2008-11-06 - Granted: 2013-06-18 - Earliest claimed: 2007-05-04 - Assignees: Hydro Dynamics, Inc. - Applicants: Bijan Kazem - Inventors: Bijan Kazem - Web page: https://patentgrep.com/patent/US8465642B2 ## CPC - C02F 1/465: by electroflotation - B03D 1/1437: {using electroflotation (waste water treatment using electroflotation C02F1/465)} - B03D 1/16: with impellers; Subaeration machines {(mixing gases or vapours with liquids B01F23/20)} - C02F 1/24: by flotation (C02F1/465 takes precedence) - C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes) - B03D: FLOTATION; DIFFERENTIAL SEDIMENTATION (sedimentation in general B01D21/00; in combination with other separation of solids B03B; sink-float separation B03B5/28; detergents, soaps C11D) ## Abstract A method and apparatus for separating impurities from a liquid stream includes a feed tank for containing an untreated liquid, a mixer for generating and mixing bubbles throughout the wastewater, and a settling tank for allowing the wastewater to settle for removal of impurities through dissolved gas floatation. The mixer includes a housing and a rotor rotatably mounted within the housing. The rotor is electrically isolated and the peripheral wall of the housing is electrically isolated and the rotor preferably has bores formed in its peripheral surface to produce cavitation to aid in mixing of fluid within the mixer. A power supply is coupled to establish a relatively positive electrical charge on the rotor and a relatively negative electrical charge on the wall of the housing. The charge causes electrolysis to occur within the fluid, which forms small low surface tension gas bubbles on the rotor and housing wall. These bubbles detach and are mixed with the fluid, where they can attach to and separate impurities through dissolved gas floatation. ## Claims ### Claim 1 A dissolved gas floatation mixer comprising: a housing having a wall; a movable member disposed in said housing and having a surface spaced from the wall of the housing; an array of irregularities on the surface of the movable member configured to generate cavitation in a fluid within the housing when the movable member is moved at a predetermined rate; at least a portion of said housing being electrically isolated and at least a portion of said movable member being electrically isolated; a motor for moving said movable member in said housing; a source of DC power electrically coupled to said portion of said housing and said portion of said movable member to establish an electrical potential difference therebetween; the positive pole of the source of DC power being electrically coupled to one of said portion of said housing and said portion of said movable member to form an anode thereof; the negative pole of the source of DC power being electrically coupled to the other one of said portion of said housing and said portion of said movable member to form a cathode thereof; at least the surface of the anode comprising a material that is resistant to oxidation to promote the formation of oxygen bubbles on the surface of the anode as a result of electrolysis when a fluid is present within the housing and DC power is supplied by the source of DC power to the anode and the cathode; and an inlet conduit and an outlet conduit coupled to said housing for delivering fluid to said housing and extracting fluid from said housing. ### Claim 2 (depends on 1) The mixer of claim 1 and wherein said housing defines a generally cylindrical interior chamber. ### Claim 3 (depends on 1) The mixer of claim 1 and wherein said movable member comprises a rotor rotatably mounted within said housing. ### Claim 4 (depends on 3) The mixer of claim 3 and wherein the irregularities comprise bores in the rotor. ### Claim 5 (depends on 4) The mixer of claim 4 and wherein said housing defines a generally cylindrical interior chamber and wherein said rotor is generally cylindrical and rotatably mounted within said interior chamber. ### Claim 6 (depends on 5) The mixer of claim 5 and wherein said DC power supply is coupled to establish on said rotor a positive electrical charge relative to said portion of said housing and at least a surface of said rotor comprises a material resistant to oxidation. ### Claim 7 (depends on 6) The mixer of claim 6 and wherein said portion of said rotor comprises an outer peripheral surface of said rotor. ### Claim 8 (depends on 1) The mixer of claim 1 wherein the material that is resistant to oxidation comprises a metal. ### Claim 9 (depends on 8) The mixer of claim 8 wherein the metal comprises titanium. ### Claim 10 (depends on 1) The mixer of claim 1 wherein the material that is resistant to oxidation comprises an oxide of a metal. ### Claim 11 (depends on 10) The mixer of claim 10 wherein the oxide of a metal comprises an oxide of titanium. ### Claim 12 (depends on 11) The mixer of claim 11 wherein the oxide of a metal comprises ruthenium titanium oxide. ### Claim 13 (depends on 1) The mixer of claim 1 wherein the material that is resistant to oxidation comprises a coating the surface of the rotor. ### Claim 14 (depends on 13) The mixer of claim 13 wherein the material that is resistant to oxidation comprises ruthenium titanium oxide. ### Claim 15 (depends on 14) The mixer of claim 14 wherein the rotor comprises titanium and the coating is on the surface of the titanium.