Method and apparatus for treating wastewater containing emulsified oil

• US 8,273,240 B2
• Filed: 09/21/2006
• Issued: 09/25/2012
• Est. Priority Date: 09/22/2005
• Status: Active Grant

• Current Assignee: Deren Hu
• Original Assignee: Deren Hu
• Inventors: Hu, Deren
• Primary Examiner(s): Olsen, Kaj K
• Assistant Examiner(s): Leong, Susan D
• Application Number:
  US11/525,195
• Publication Number:
  US 20070062881A1
• Time in Patent Office: 2,196 Days
• Field of Search: 204/268, 204/278, 204/284, 204/290, 205/742, 205753-754, 205/758, 205/760
• US Class Current: 205/760
• CPC Class Codes: C02F 1/40 Devices for separating or removing fatty or oily substances or similar floating material cleaning or keeping clear the surface of open water from oil or like materials E02B15/04; devices in sewers for separating liquid or solid substances from sewage E03F5/14, e.g. for use in drains leading to the sewer E03F5/16
• CPC Class Codes: C02F 1/46114 Electrodes in particulate form or with conductive and/or non conductive particles between them
• CPC Class Codes: C02F 1/4674 with halogen or compound of halogens, e.g. chlorine, bromine
• CPC Class Codes: C02F 2001/46138 Electrodes comprising a substrate and a coating
• CPC Class Codes: C02F 2101/325 Emulsions
• CPC Class Codes: C02F 2103/16 from metallurgical processes, i.e. from the production, refining or treatment of metals, e.g. galvanic wastes
• CPC Class Codes: C02F 2305/023 Reactive oxygen species, singlet oxygen, OH radical

Abstract

In one embodiment of the present invention, a method for treating wastewater that contains emulsified oil is provided. The method comprises feeding the wastewater that contains the emulsified oil to an electrolytic tank, and oxidatively electrolyzing the wastewater that contains the emulsified oil using indissoluble electrodes. The negatively charged emulsified oil particles in the wastewater are neutralized on a surface of an anode during the oxidative electrolysis. The anode comprises an indissoluble electrode with oxygen radical-generating characteristics. The method further comprises particle group electrolyzing the wastewater using particle groups, and discharging the treated wastewater.

Claims

1. A method for treating wastewater that contains emulsified oil, the method comprising:

feeding the wastewater that contains the emulsified oil to an electrolytic tank;

de-emulsifying a quantity of the emulsified oil contained in the wastewater by oxidative electrolysis using indissoluble electrodes, wherein negatively charged emulsified oil particles in the wastewater are electrically neutralized on a surface of an anode during the oxidative electrolysis, the anode comprising an indissoluble electrode with oxygen radical-generating characteristics;

introducing the wastewater containing the remaining emulsified oil to the bottom of the electrolytic tank containing active carbon particles and insulating plastic particles;

electrolyzing the wastewater containing the remaining emulsified oil to de-emulsify the remaining emulsified oil, using the active carbon particles mixed with the wastewater as electrodes; and

discharging the treated wastewater,

wherein the anode both neutralizes the negative charges on the emulsified oil particles and produces hydroxyl radicals during the oxidative electrolysis, the hydroxyl radicals reacting with the emulsified oil particles such that de-emulsifying the emulsified oil particles is accelerated and no solid sediments are produced throughout the oxidative electrolysis process by the electrodes.

2. The method of claim 1, wherein de-emulsifying the negatively charged emulsified oil particles produces oil aggregates that float upwardly to an upper part of the electrolytic tank.

3. The method of claim 1, wherein a voltaic concentration for the oxidative electrolysis using indissoluble electrodes is about 1.4˜

1.6 Ah/L.

4. The method of claim 1, wherein an electrolytic current for the particle group electrolysis is about 5˜

10 A.

5. The method of claim 1, wherein each of the indissoluble electrodes comprises a metal base coated with an oxide.

6. The method of claim 5, wherein the metal base comprises titanium.

7. The method of claim 5, wherein the oxide is selected from the group consisting of titanium dioxide, tin oxide, iridium dioxide, and combinations thereof.

8. The method of claim 1, wherein the active carbon particles are mixed with the insulating plastic particles, and the active carbon particles and the insulating plastic particles are disposed on the bottom of an electrobath.

9. The method of claim 1, further comprising separating non-emulsified oil in the wastewater from the wastewater containing emulsified oil by a conventional separation process before the de-emulsifying.

10. The method of claim 9, wherein the conventional separation process comprises a process using gravitational and filtration-adsorption separation.

11. The method of claim 4, wherein a voltage for the particle group electrolysis is about 30˜

50 V.

12. The method of claim 1, wherein the discharged wastewater has an oil content of about 15 mg/L or less.