Treatment of oil and grease in water using algae

Patent metadata

Field	Value
Publication number	US-11066316-B2
Application number	US-201414909522-A
Country	US
Kind code	B2
Filing date	Aug 1, 2014
Priority date	Aug 2, 2013
Publication date	Jul 20, 2021
Grant date	Jul 20, 2021

Abstract

A method for treating an oil-containing medium including oil or grease or both oil and grease includes the steps of combining algae with an oil-containing medium and allowing the algae to engulf or uptake at least a portion of the oil or grease in the oil-containing medium. A mixture for treating oil or grease or both oil and grease includes an oil-containing medium including oil or grease or both oil and grease and phagotrophic algae that engulf or uptake at least a portion of the oil or grease in the oil-containing medium.

First claim

What is claimed is:

1. A method for treating an industrial wastewater medium, the method comprising steps of:
providing a wastewater stream including industrial wastewater and at least one of oil or grease, the at least one of oil or grease being in the form of droplets having an initial droplet size, wherein at least a portion of the at least one of oil or grease is insoluble in the industrial wastewater,
combining phagotrophic algae with the wastewater stream to form a combined medium, wherein the combined medium has a maximum cell number concentration of the phagotrophic algae of 2.89×10 7 algae cells/mL of the combined medium, wherein the phagotrophic algae are selected from the group consisting of Dinobryon, Chrysophaerella, Uroglena, Catenochrysis, Chromulina , and Chrysococcus,
mechanically agitating or mechanically mixing the combined medium to thereby form the droplets into a smaller droplet size smaller than the initial droplet size, and
allowing the algae to engulf at least a portion of the insoluble portion in the combined medium, wherein the wastewater stream has an oil concentration of 12.8 g/L or more prior to the step of combining and the combined medium has an oil concentration of 5.9 g/L or less after the step of allowing.

2. The method of claim 1 , wherein the wastewater stream further includes a mineral medium, and wherein the method further includes a step of growing the phagotrophic algae within the combined medium, wherein the mineral medium comprises one or more of nitrilotriacetic acid, KH 2 PO 4 , MgCO 3 , CaCO 3 , NH 4 Cl, MgSO 4 .7H 2 O, yeast extract, peptone, Na 2 EDTA, FeCl 3 .6H 2 O, H 3 BO 3 , thiamine, biotin, MnCl 2 .4H 2 O, ZnSO 4 .7H 2 O, CoCl 2 .6H 2 O, and Na 2 MoO 4 .2H 2 O.

3. A method for treating an industrial wastewater medium, the method comprising steps of:
providing a wastewater stream including industrial wastewater and at least one of oil or grease, the at least one of oil or grease being in the form of droplets having an initial droplet size, wherein at least a portion of the at least one of oil or grease is insoluble in the industrial wastewater,
combining phagotrophic algae with the wastewater stream to form a combined medium, wherein the combined medium has a maximum cell number concentration of the phagotrophic algae of 2.89×10 7 algae cells/mL of the combined medium, wherein the phagotrophic algae are selected from Ochromonas danica, Ochromonas malhamensis, Ochromonas tuberculata , and Ochromonas vallescia,
mechanically agitating or mechanically mixing the combined medium to thereby form the droplets into a smaller droplet size smaller than the initial droplet size, and
allowing the algae to engulf at least a portion of the insoluble portion in the combined medium, wherein the wastewater stream has an oil concentration of 12.8 g/L or more prior to the step of combining and the combined medium has an oil concentration of 5.9 g/L or less after the step of allowing.

4. The method of claim 1 , further comprising steps of collecting the algae and producing an algal product, following the step of allowing.

5. The method of claim 1 , wherein the wastewater stream comprises waste cooking oil.

6. The method of claim 1 , further comprising steps of
depleting at least one soluble nutrient component essential for microbial growth, and
allowing, after the step of depleting, the phagotrophic algae to grow as the predominant algae.

7. A method for treating an industrial wastewater medium, the method comprising steps of:
combining phagotrophic algae with a wastewater medium including industrial wastewater and at least one of oil or grease to form a combined medium, the at least one of oil or grease being in the form of droplets having a droplet size, wherein at least a portion of the at least one of oil or grease in the combined medium is insoluble in the industrial water, wherein the combined medium has a maximum cell number concentration of the phagotrophic algae of 2.89×10 7 algae cells/mL of the combined medium, wherein the phagotrophic algae are selected from the group consisting of Dinobryon, Chrysophaerella, Uroglena, Catenochrysis, Chromulina , and Chrysococcus,
adding a surfactant to the combined medium, wherein the surfactant functions as both a nonionic surfactant and an emulsifier, wherein the amount of the surfactant added is from 0.01 g/L or more to 0.20 g/L or less, based on the total volume of the combined medium,
mechanically agitating or mechanically mixing the combined medium to thereby form the droplets into a smaller droplet size smaller than the initial droplet size, and
allowing the algae to engulf at least a portion of the insoluble portion in the combined medium, wherein the wastewater medium has an oil concentration of 10 g/L or more prior to the step of combining and the combined medium has an oil concentration of 2 g/L or less after the step of allowing.

8. The method of claim 1 , wherein the steps of combining and allowing occur at a dissolved oxygen content of from 0.05 mg/L or more to 5 mg/L or less and at a pH of from 4.0 or more to 6.0 or less.

9. The method of claim 1 , wherein the wastewater stream includes both of oil and grease.

10. The method of claim 1 , wherein the method occurs within a timeframe of from 3 hours or more to 3 days or less.

11. The method of claim 7 , wherein the method occurs within a timeframe of from 3 hours or more to 3 days or less.

12. The method of claim 7 , wherein the amount of surfactant added is from 0.05 g/L or more to 0.10 g/L or less, based on the total volume of the combined medium.

13. The method of claim 12 , wherein the surfactant is polysorbate 80.

14. The method of claim 1 , wherein the combined medium includes the at least one of oil or grease as a sole carbon source for growth of the phagotrophic algae.

15. The method of claim 1 , wherein the step of providing includes providing the wastewater stream from a chemical plant or an oil refinery.

16. The method of claim 1 , wherein the method occurs within a timeframe of about 1 hour.

17. The method of claim 1 , wherein the method occurs within a timeframe of about 3 hours.

18. The method of claim 1 , wherein the step of mechanically agitating or mechanically mixing utilizes a magnetic stir bar.

19. The method of claim 1 , wherein the combined medium includes an upper oil-containing phase and a lower aqueous phase, wherein, during the step of allowing, the droplets and a percentage of the phagotrophic algae float to the upper oil-containing phase, and wherein, after the step of allowing, the percentage of phagotrophic algae floated to the upper oil-containing phase is from 63 percent or more to 79 percent or less, as determined by optical density.

20. The method of claim 2 , wherein, during the step of growing the phagotrophic algae, the phagotrophic algae have a maximum specific growth rate (μ max ) of from 0.029 h −1 to 0.23 h −1 , as determined by the slope of a semi-logarithmic plot of cell concentration (g/L) versus cultivation time (hours).

Assignees

• Ju Lu Kwang
• Hosseini Majid
• Univ Akron

Inventors

• Ju Lu-Kwang
• Hosseini Majid

Classifications

• C02F3/322 Primary

  use of algae · CPC title

• C02F2101/32

  Hydrocarbons, e.g. oil · CPC title

• C02F2209/06

  pH · CPC title

• C02F2103/10

  from quarries or from mining activities · CPC title

• C02F2103/322

  from vegetable oil production, e.g. olive oil production · CPC title