Non-stripping bioreactor for biological sulfide oxidation from wastewaters and groundwaters containing hydrogen sulfide

Patent metadata

Field	Value
Publication number	US-2017305773-A1
Application number	US-201715491732-A
Country	US
Kind code	A1
Filing date	Apr 19, 2017
Priority date	Apr 20, 2016
Publication date	Oct 26, 2017
Grant date	—

Abstract

A method is presented for biological removal of contaminants like sulfide from ground waters and industrial waters. A portion of the bioreactor effluent water is recycled to the bioreactor and the sulfide oxidizing bacteria by biological oxidation oxidizes sulfides in the water to produce soluble sulfates. The present invention uses a packed bed bioreactor configuration that uses packing material to maximize the concentration of sulfide oxidizing bacteria.

First claim

1 . A process for removing sulfides from a feed water stream in a bioreactor wherein said water stream contains from about 1 mg/L to about 2500 mg/L of sulfur compounds on an elemental sulfur basis, comprising:
(a) passing said water stream through a fixed film bioreactor containing a effective quantity of autotrophic obligate chemolithotrophic bacteria immobilized on a packing material within said bioreactor; (b) recycling a portion of a recycle water from a bioreactor effluent to the bioreactor; (c) passing air to the said recycle water to saturate the recycle water with dissolved oxygen; (d) mixing the recycle water with the feed water stream to provide a mixed water stream; (e) oxidizing said sulfides to form sulfates; and (f) removing a purified water stream comprising less than about 0.5 mg/L sulfides from said bioreactor.

2 . The process of claim 1 wherein said feed water stream is selected from the group consisting of briny ground water, fracking wastewater, sulfidic caustic wastewater, sour water from refining or from petrochemical processing, sulfidic sewer water, and sour water generated by anaerobic digesters and mixtures thereof.

3 . The process of claim 1 wherein said autotrophic obligate chemolithotrophic bacteria are selected from the group consisting of Acidithiobacillus ferrooxidans, Thermithiobacillus tepidarius, Sulfurimonas denitrificans, Desulfocapsa sulfoexigens , and some species of Thiobacillus, Halothiobacillus, Acidiphilium, Thiomicrospira, Sulfolobus, Acidianus, Sulfurisphaera , and Sulfurococcus.

4 . The process of claim 1 wherein said purified water stream comprises less than about 0.2 mg/L sulfides.

5 . The process of claim 1 wherein the ratio of the recycle water to the feed water stream is about 18 to 1.

6 . The process of claim 1 further comprising splitting the recycle water to a first and a second bioreactor.

7 . The process of claim 1 wherein the concentration of oxygen dissolved in the recycle water is about 12 to 1.

8 . The process of claim 1 wherein a majority of sulfides within said mixed water stream are oxidized to sulfates by said chemolithotrophic sulfur oxidizing bacteria.

9 . The process of claim 1 wherein said packing material contains about 10,000 mg/L of fixed biomass of said bacteria.

10 . The process of claim 1 wherein said water stream comprises a salt concentration of more than 1% total salinity.

11 . The process of claim 1 wherein said mixed water stream flow through said autotrophic obligate chemolithotrophic bacteria.

12 . The process of claim 1 wherein said purified water is reused in an industrial process or discharged into nearby ground water.

Assignees

• Uop Llc

Inventors

• Lupton F Stephen
• Sheridan William

Classifications

• C02F2103/365

  from petrochemical industry (e.g. refineries) · CPC title

• C02F3/345 Primary

  for biological oxidation or reduction of sulfur compounds · CPC title

• C02F2103/06

  Contaminated groundwater or leachate · CPC title

• C02F3/10

  Packings; Fillings; Grids (packing elements in general B01J19/30, B01J19/32) · CPC title

• C02F2301/046

  Recirculation with an external loop · CPC title