KR-102961411-B1 - Material For Sulfur Utilizing Denitrification Using Sulfur Cycle

KR102961411B1KR 102961411 B1KR102961411 B1KR 102961411B1KR-102961411-B1

Abstract

The present invention relates to an electron donor circulating sulfur denitrifying agent comprising: sulfur (S O ) particles; any one iron sulfide particle selected from a group of iron sulfide particles consisting of Fe 2 S 3 particles, FeS particles, and FeS 2 particles, or a mixture of two or more iron sulfide particles; iron hydroxide (Fe(OH) 3 ) particles; sulfur oxidizing denitrifying bacteria; and sulfate reducing bacteria. The electron donor-circulating sulfur denitrifying agent of the present invention has the advantage of maintaining denitrification activity for a long time by minimizing the replenishment of additional electron donors compared to conventional denitrification reactions using sulfur-oxidizing denitrifying bacteria, because sulfur, which is an electron donor, is circulated through an internal reaction during the denitrification reaction process of sulfur-oxidizing denitrifying bacteria. In addition, the electron donor circulating sulfur denitrifying agent of the present invention has the advantage that when sulfate ions generated during sulfation denitrification are converted into hydrogen sulfide by sulfate-reducing bacteria (SRB), iron hydroxide (Fe(OH) ₃ ) chemically adsorbs and removes them, so there is no odor caused by hydrogen sulfide. In addition, the electron donor circulating sulfur denitrifying agent of the present invention has the advantage of maintaining denitrification activity for a longer period of time compared to conventional denitrification reactions using sulfur-oxidizing denitrifying bacteria, as the consumption of alkalinity is minimized by reusing hydrogen ions generated during the denitrification reaction process of sulfur-oxidizing denitrifying bacteria or by the generated iron hydroxide (Fe(OH) ₃ ) particles. Therefore, it is expected that using the electron donor-circulating sulfur denitrifying agent of the present invention will enable a stable denitrification reaction without generating odors, even while minimizing the supply of additional electron donors and alkalinity.

Inventors

오상은
김승규
아눕 구룽
강우창

Assignees

강원대학교산학협력단

Dates

Publication Date: 20260511
Application Date: 20240229
Priority Date: 20230419

Claims (11)

The present invention relates to sulfur ( S₂O ) particles; Any one iron sulfide particle selected from the group of iron sulfide particles consisting of Fe₂S₃ particles, FeS particles, and FeS₂ particles , or a mixture of two or more iron sulfide particles; Iron hydroxide (Fe(OH) ₃ ) particles; Sulfur Oxidizing Denitrifying Bacteria; and Electron donor cyclic sulfur denitrifying agent containing sulfate-reducing bacteria.
In claim 1, the sulfur ( SO₄ ) particles are converted into sulfate ions ( SO₄²⁻ ) by being used as electron donors in the process in which the sulfur - reducing denitrifying bacteria decompose nitrate ions ( NO₃⁻ ) into nitrogen gas ( N₂ ); the sulfate ions ( SO₄²⁻ ) are converted into hydrogen sulfide ( H₂S ) by the sulfate-reducing bacteria; the hydrogen sulfide ( H₂S ) reacts with the iron hydroxide (Fe(OH) ₃ ) particles to be converted into sulfur ( SO₄ ) particles and FeS particles; the sulfur ( SO₄ ) particles and FeS particles react to be converted into FeS₂ particles; An electron donor circulating sulfur denitrifying agent characterized in that the sulfur (S O ) particles, the FeS particles, and the FeS 2 particles are used as electron donors in the process in which the sulfur-oxidizing denitrifying bacteria decompose nitrate ions (NO 3- ) into nitrogen gas (N 2 ).
In claim 1, the Fe₂S₃ particles are converted into FeS particles or FeS₂ particles , and any one iron sulfide particle selected from the group of iron sulfide particles composed of the converted FeS particles and FeS₂ particles, or a mixture of iron sulfide particles thereof, is used as an electron donor in the process in which the sulfation-reducing denitrifying bacteria decompose nitrate ions ( NO₃⁻ ) into nitrogen gas ( N₂ ) and is converted into sulfate ions ( SO₄²⁻ ) and iron hydroxide (Fe(OH ) ₃ ) particles; the sulfate ions ( SO₄²⁻ ) are decomposed into sulfate ions ( HS⁻ ) by the sulfate-reducing bacteria and then converted into hydrogen sulfide ( H₂S ); the hydrogen sulfide ( H₂S ) reacts with the iron hydroxide (Fe(OH) ₃ ) particles and is converted into sulfur ( SO₄ ) particles and FeS particles; The electron donor circulating sulfur denitrifying agent is characterized in that the sulfur ( S₂O ) particles and the FeS particles react to be converted into FeS₂ particles; and the sulfur ( S₂O ) particles, the FeS particles, and the FeS₂ particles are used as electron donors in the process in which the sulfur-oxidizing denitrifying bacteria decompose nitrate ions ( NO₃⁻ ) into nitrogen gas ( N₂ ).
In claim 1, any one iron sulfide particle selected from the group of iron sulfide particles composed of FeS particles and FeS₂ particles, or a mixture of two or more iron sulfide particles , is used as an electron donor in the process in which the sulfation-reducing denitrifying bacteria decompose nitrate ions (NO₃⁻) into nitrogen gas (N₂) and is converted into sulfate ions (SO₄²⁻ ) and iron hydroxide ( Fe(OH) ₃ ) particles; the sulfate ions (SO₄²⁻) are decomposed into sulfate ions ( HS⁻ ) by the sulfate-reducing bacteria and then converted into hydrogen sulfide ( H₂S ); the hydrogen sulfide ( H₂S ) reacts with the iron hydroxide (Fe(OH) ₃ ) particles to be converted into sulfur ( SO₄ ) particles and FeS particles; the sulfur ( SO₄ ) particles and FeS particles react to be converted into FeS₂ particles; An electron donor circulating sulfur denitrifying agent characterized in that the sulfur (S O ) particles, the FeS particles, and the FeS 2 particles are used as electron donors in the process in which the sulfur-oxidizing denitrifying bacteria decompose nitrate ions (NO 3- ) into nitrogen gas (N 2 ).
An electron donor-circulating sulfur denitrifying agent according to claim 1, characterized in that the hydrogen ions (H + ) generated during the process in which the sulfur-oxidizing denitrifying bacteria decompose nitrate ions ( NO3- ) into nitrogen gas ( N2 ) using the sulfur ( S0 ) particles as electron donors consume the hydrogen ions (H + ) during the process in which the sulfur-oxidizing denitrifying bacteria decompose nitrate ions ( NO3- ) into nitrogen gas ( N2 ) using the FeS2 particles as electron donors, or the decrease in pH and alkalinity is mitigated by iron hydroxide (Fe(OH) 3 ) particles generated during the process in which the sulfur-oxidizing denitrifying bacteria denitrify using the FeS2 particles as electron donors.
An electron donor circulating sulfur denitrifying agent according to claim 1, characterized in that the sulfur ( S₂O ) particles; any one iron sulfide particle selected from the group of iron sulfide particles consisting of Fe₂S₃ particles, FeS₃ particles, and FeS₂ particles, or a mixture of two or more iron sulfide particles; and the iron hydroxide (Fe(OH) ₃ ) particles; can be mixed with a binder to form pellets.
A water treatment column filled with a circulating sulfur denitrifying agent, an electron donor according to any one of claims 1 to 6.
A water treatment column filled with an electron donor circulating sulfur denitrifying agent, characterized in that, in claim 7, the column is an upward-flow type.
A first step of preparing an iron compound particle mixture comprising: any one iron sulfide particle selected from a group of iron sulfide particles consisting of Fe₂S₃ particles, FeS₃ particles, and FeS₂ particles, or a mixture of two or more iron sulfide particles; and iron compound particle mixture comprising iron hydroxide (Fe(OH) ₃ ) particles; A second step of preparing a sulfur ( S₂O )-iron compound particle mixture by mixing sulfur ( S₂O ) particles with the mixture of iron compound particles; and A third step of preparing an electron donor-circulating sulfur denitrifying agent by inoculating the above sulfur (S O )-iron compound particle mixture with sulfur oxidizing denitrifying bacteria and sulfate reducing bacteria; A method for manufacturing a cyclic sulfur denitrifying agent containing an electron donor.
A method for manufacturing an electron donor circulating sulfur denitrifying agent according to claim 9, wherein the sulfur ( S₂O₅ )-iron compound particle mixture is characterized by the sulfur ( S₂O₅ ) particles and the iron compound particle mixture being mixed in a weight ratio of 0.5 to 5:1.
A method for manufacturing an electron donor-circulating sulfur denitrifying agent, characterized in that, in claim 9, the inoculation of the sulfur-reducing denitrifying bacteria and sulfate-reducing bacteria utilizes one or more mixtures selected from the group consisting of aerobic sludge in a sewage treatment plant, anaerobic sludge in a sewage treatment plant, and soil microorganisms.

Description

Electron Donor Cyclical Sulfur Denitrification Material For Sulfur Utilizing Denitrification Using Sulfur Cycle The present invention relates to an electron donor circulating sulfur denitrifying agent, and more specifically, to an electron donor circulating sulfur denitrifying agent comprising: sulfur ( S₂O₅ ) particles; any one iron sulfide particle selected from a group of iron sulfide particles consisting of Fe₂S₃ particles, FeS₂ particles, and FeS₂ particles, or a mixture of two or more iron sulfide particles; iron hydroxide (Fe(OH) ₃ ) particles; sulfur oxidizing denitrifying bacteria; and sulfate reducing bacteria. Nitrate nitrogen ( NO₃⁻-N ) is a toxic substance that causes not only infant cyanosis but also cancer; therefore, the amount contained in discharged treated water is strictly managed in accordance with rigorous national water quality standards. For example, in the case of groundwater , the content of nitrate ions ( NO₃⁻ ) is limited to less than 20 mg/ℓ, and in the case of drinking water , the content of nitrate ions ( NO₃⁻ ) is limited to less than 10 mg/ℓ. There are heterotrophic denitrification and autotrophic denitrification methods for removing nitrate ions contained in contaminated water by denitrification. The heterotrophic denitrification method is a method that denitrifies nitrate ions ( NO₃⁻ ) into nitrogen gas ( N₂ ) under anaerobic conditions using organic matter (carbon source) in sewage. However, the heterotrophic denitrification method had the disadvantage of being uneconomical and generating a large amount of sludge when treating sewage with a low C/N ratio, as it requires the injection of organic matter such as methanol. In contrast, the above-mentioned autotrophic denitrification method is characterized by the fact that it does not require the injection of organic matter , as it uses various inorganic substances as electron donors. Specifically, in the above-mentioned autotrophic denitrification method, sulfur-oxidizing denitrifying bacteria utilize sulfur as an electron donor to denitrify nitrate ions ( NO₃⁻ ) into nitrogen gas ( N₂ ). However, the above-mentioned autotrophic denitrification method had a problem in which the alkalinity of the treated water decreased and denitrification efficiency was reduced because sulfur was oxidized by sulfur-oxidizing denitrifying bacteria during the denitrification process and converted into sulfate ions ( SO₄²⁻ ) , generating hydrogen ions. In addition, there was a problem in which odors were generated as the sulfate ions generated during the denitrification process were converted into hydrogen sulfide ( H₂S ) by sulfate-reducing bacteria. Iron hydroxide (Fe(OH) 3 ) particles are obtained by reacting mine sludge containing a large amount of iron with an alkaline aqueous solution (such as Ca(OH) 2 ). Since these iron hydroxide particles have the effect of chemically adsorbing hydrogen sulfide, they are used as desulfurization adsorbents for exhaust gases. When the iron hydroxide (Fe(OH) 3 ) particles adsorb hydrogen sulfide , they are converted into iron sulfide particles (one or more of Fe2S3 , FeS , and FeS2 ), which degrades the hydrogen sulfide adsorption performance; consequently, they have been disposed of in landfills as waste desulfurization adsorbents. The iron sulfide (one or more of Fe2S3 , FeS, and FeS2 ) can be used as an electron donor and utilized in denitrification reactions by sulfur-oxidizing denitrifying bacteria. Recently, research is being conducted to recycle these discarded waste desulfurization adsorbents into sulfur denitrifying agents. The above-mentioned spent desulfurization adsorbent contains CaCO3 in addition to iron sulfide (one or more of Fe₂S₃ , FeS , and FeS₂ ), and since it acts as an electron donor by sulfur-reducing denitrifying bacteria and is utilized in the denitrification process while consuming hydrogen ions, the pH does not decrease, which has the advantage of maintaining alkalinity. Furthermore, when the denitrification process is performed using iron sulfide particles (one or more of Fe₂S₃ , FeS, and FeS₂ ) contained in the above-mentioned spent desulfurization adsorbent , the pores and microcracks generated during the adsorption process of hydrogen sulfide create a large specific surface area, which acts as a favorable environment for the attachment and growth of sulfur-reducing denitrifying bacteria, thereby having the advantage of excellent denitrification efficiency. However, if only the above iron sulfide (one or more of Fe₂S₃ , FeS , and FeS₂ ) is applied to the denitrification reaction, the electron donors contained in the iron sulfide are oxidized into sulfate ions and released; that is, when all the sulfur in the iron sulfide (one or more of Fe₂S₃ , FeS, and FeS₂ ) is consumed and becomes iron hydroxide (Fe(OH) ₃ ) , the denitrification efficiency by sulfur-reducing denitrifying bacteria decreases, and there is the inconvenience of having to periodically replace the iron sulfide.