A sewage denitrification device and method based on an externally applied direct current power enhanced sulfur autotrophic denitrification system

Abstract

The present application relates to a kind of based on additional direct current power intensification sulfur autotrophic denitrification system Sewage denitrification device and method, belong to sulfur autotrophic denitrification wastewater treatment technical field.The method combines electrically enhanced microbial method and sulfur autotrophic denitrifying bacteria to carry out the degradation of nitrate nitrogen, specifically, by electrophoresis deposition method, iron sulfide is loaded on carbon felt as the cathode of reactor, and constructs additional direct current power intensification system;With sulfur autotrophic denitrifying bacteria liquid medium as test water body, with sulfur autotrophic denitrifying bacteria as degrading bacteria, construct sulfur autotrophic denitrifying bacteria reaction system.In the present application, solid sulfur source is used to carry out sulfur autotrophic denitrification reaction, and under the effect of additional direct current power intensification, removal efficiency is significantly improved.

Description

Technical Field

[0001] This invention relates to the field of sulfur autotrophic denitrification wastewater treatment technology, specifically to a wastewater denitrification device and method based on an externally powered, electrically enhanced sulfur autotrophic denitrification system. Background Technology

[0002] Biological denitrification has become a hot topic and a challenging issue in water treatment in recent years. Among these, sulfur autotrophic denitrification (SAD) technology, with its advantages of requiring no additional carbon source, readily available sulfur source, and high denitrification efficiency, shows great application potential. However, traditional SAD processes are not entirely efficient when using solid sulfur sources. To overcome this limitation, we innovatively introduce an external DC power supply, aiming to optimize the metabolic processes of microorganisms by utilizing the interaction between microorganisms and the electron transfer medium, thereby improving the denitrification capacity of SAD strains. Summary of the Invention

[0003] The purpose of this invention is to provide a wastewater denitrification device and method based on an externally powered, electro-enhanced sulfur autotrophic denitrification system. This method combines electro-enhanced microbial methods with sulfur autotrophic denitrifying bacteria to degrade nitrate nitrogen. Specifically, iron sulfide is loaded onto carbon felt as the cathode of the reactor via electrophoretic deposition to construct an externally powered, electro-enhanced system. A sulfur autotrophic denitrifying bacteria liquid culture medium is used as the test water, and sulfur autotrophic denitrifying bacteria are used as the degrading bacteria to construct a sulfur autotrophic denitrifying bacteria reaction system. The key factors influencing the degradation of nitrate nitrogen in the externally powered, electro-enhanced sulfur autotrophic denitrification system were identified, and a control method was established to achieve efficient nitrate degradation.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A wastewater denitrification device based on an externally powered electro-enhanced sulfur autotrophic denitrification system includes several groups of anaerobic bioreactors installed in parallel. Each group of anaerobic bioreactors has two electrode holes on its upper side, for placing a cathode and an anode respectively. The electrode holes are connected to an external DC power supply, and each group of anaerobic bioreactors is connected to an external DC power supply. A temperature control device is installed on the outer wall of the anaerobic bioreactor, and the temperature is controlled by a heating tape and a temperature control switch. A rotor is placed inside the anaerobic bioreactor, and the anaerobic bioreactor is located on a magnetic stirrer. The rotation of the rotor achieves the purpose of homogenizing the medium.

[0005] Furthermore, the cathode material is a carbon felt loaded with iron sulfide.

[0006] A wastewater denitrification method based on an externally powered electro-enhanced sulfur autotrophic denitrification system includes the following steps: The first step is the preparation of carbon felt loaded with iron sulfide. (1) The carbon felt is 2 cm*4 cm in size. Before loading, the carbon felt is soaked in concentrated nitric acid for 12 h to remove organic matter. Then it is ultrasonically cleaned with distilled water until neutral and dried in a vacuum drying oven at 60°C. (2) Dissolve PVA in sterile distilled water to prepare a PVA solution; (3) Dissolve CTAB in sterile distilled water to prepare CTAB solution; (4) PVA solution, CTAB solution and iron sulfide were added to a beaker in sequence, followed by sterile distilled water. A stir bar was added inside the beaker, and the beaker was placed on a magnetic stirrer. An external DC power supply was applied, and iron sulfide was loaded onto the carbon felt at 35°C and 15V for 1 hour. After loading, the carbon felt was placed in a vacuum drying oven to dry. The dosage of PVA was 1 g / L, the dosage of CTAB was 0.4 g / L, the dosage of iron sulfide was 4 g / L, and the solution volume during loading was 250 mL. The second step involves the cultivation and activation of sulfur-autotrophic denitrifying bacteria. The sulfur autotrophic denitrifying strain selected in this invention originated from a sulfur autotrophic denitrifying packed column that had been operating stably for over a year within a neighboring research group. During the extraction of the mixed bacteria, the reactor was first shut down and the original solution inside was completely drained. Then, isobaric sulfur particles with biofilm attached were extracted from three different locations: the top, middle, and bottom. These extracted sulfur particles were placed in a beaker, and an appropriate amount of deionized water was added at a ratio of two milliliters of deionized water per gram of elemental sulfur. The mixture was stirred for 1 minute to ensure that the sulfur autotrophic denitrifying biofilm was effectively detached from the sulfur particles. Next, the suspension containing the sulfur autotrophic denitrifying biofilm was transferred to a centrifuge tube and centrifuged at 8000 rpm for 5 minutes. After centrifugation, the supernatant was removed, and the precipitate at the bottom was the desired sulfur autotrophic denitrifying mixed bacteria. The cultivation and storage process of sulfur autotrophic denitrifying bacteria is as follows: First, prepare the culture medium, autoclave it, and then cool it to a suitable temperature. Next, inoculate 5 mL of the initial sulfur autotrophic denitrifying mixed bacterial suspension into a container containing 200 mL of culture medium and incubate at 37°C and 150 rpm for 46 hours to expand the population. Transfer the bacterial suspension to centrifuge tubes and obtain the precipitate strain by high-speed centrifugation. Add sterilized and cooled PBS to the isolated bacterial strain, mix thoroughly, and prepare OD. 600 Prepare a bacterial suspension with a concentration of 0.03 for later use; store the prepared bacterial suspension in a refrigerator at 4°C. The third step is to establish an external DC power supply to enhance the sulfur autotrophic denitrification system. Carbon felt loaded with iron sulfide was used as the cathode of the anaerobic bioreactor, and carbon felt unloaded with iron sulfide was used as the anode of the anaerobic bioreactor. Sulfate autotrophic denitrifying bacteria were inoculated into the reactor, and after sealing, the reactor was placed on a magnetic stirrer and cultured at a speed of 150 rpm.

[0007] Furthermore, in the third step of inoculating sulfur-autotrophic denitrifying bacteria, the sulfur-autotrophic denitrifying bacteria are washed with PBS and then prepared into a bacterial suspension, the OD of which is... 600 =0.03, the inoculum volume of bacterial suspension for each anaerobic reactor is 5 mL.

[0008] Furthermore, the culture conditions for the second step of sulfur autotrophic denitrifying bacteria are as follows: 30℃, anaerobic; 980mL distilled water, 5g NaS2O3·5H2O, 2.0g KH2PO4, 1.7g NaNO3, 1g NaHCO3, 0.5g NH4Cl, 20.0g agar, 10mL vitamin solution, 10mL mineral solution, pH 7.0±0.2, sterilized at 121℃ for 15min.

[0009] Furthermore, the liquid culture medium for the sulfur-autotrophic denitrifying bacteria in the second step is as follows: 30℃, anaerobic; 980 mL distilled water, 5 g NaS2O3·5H2O, 2.0 g KH2PO4, 1.7 g NaNO3, 1 g NaHCO3, 0.5 g NH4Cl, 10 mL vitamin solution, 10 mL mineral solution, pH 7.0±0.2, sterilized at 121℃ for 15 min.

[0010] Further, the second step of activating sulfur autotrophic denitrifying bacteria is as follows: ① Prepare 12 sulfur autotrophic denitrification liquid culture media; ② After sterilizing the surface of the test tube slant, open it in a clean bench; ③ Gently scrape the bacteria off the test tube slant with a sterile inoculation loop; ④ Place the bacteria scraped off with the inoculation loop into the liquid culture medium; ⑤ Incubate the liquid culture medium under the above culture conditions. Once the bacteria have grown, it is ready for use.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. External power can enhance microbial reactions through various mechanisms. By using external power, the electron transfer process of microorganisms can be regulated, improving their activity and metabolic efficiency, thereby enhancing the sulfur autotrophic denitrification process.

[0012] 2. In the past, sulfur autotrophic denitrification reactions often used dissolved sulfur sources. However, in this invention, a solid sulfur source is used for sulfur autotrophic denitrification reactions, and the removal efficiency is significantly improved under the effect of external DC power supply. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of the present invention; In the diagram, 1 is the power supply, 2 is the anaerobic reactor, 3 is the electrode clamp, 4 is the loaded iron sulfide carbon felt, 5 is the rotor, and 6 is the DC regulated power supply. Detailed Implementation

[0014] The technical solution and effects of the present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0015] The present invention discloses a wastewater denitrification device based on an externally powered electro-enhanced sulfur autotrophic denitrification system, comprising: a power source 1, an anaerobic reactor 2, an electrode clamp 3, a loaded iron sulfide carbon felt 4, a rotor 5, and a DC regulated power supply 6. Example 1

[0016] A method for wastewater denitrification based on an externally powered electro-enhanced sulfur autotrophic denitrification system includes the following steps: (1) Carbon felt loaded with iron sulfide treatment PVA was dissolved in sterile distilled water to prepare a PVA solution; CTAB was dissolved in sterile distilled water to prepare a CTAB solution; the PVA solution, CTAB solution, and iron sulfide were added to a beaker in sequence, followed by the addition of sterile distilled water. A stir bar was added inside the beaker, which was then placed on a magnetic stirrer. An external DC power supply was applied, and the carbon felt was loaded with iron sulfide at 35°C and an external voltage of 15V. After the loading was completed, the carbon felt was placed in a vacuum drying oven to dry.

[0017] (2) Cultivation and activation of sulfur autotrophic denitrifying bacteria (3) Establishment of an external DC power supply-enhanced sulfur autotrophic denitrification system The anaerobic bioreactor uses carbon felt loaded with iron sulfide as the cathode and unloaded carbon felt as the anode. Sulfate-autotrophic denitrifying bacteria are inoculated into the reactor, which is then sealed and placed on a magnetic stirrer at 150 rpm with an external DC power supply of 0.25V. Wastewater parameters tested include nitrate nitrogen, ammonia nitrogen, nitrite nitrogen, sulfate, and pH. Example 2

[0018] A method for wastewater denitrification based on an externally powered electro-enhanced sulfur autotrophic denitrification system includes the following steps: (1) Carbon felt loaded with iron sulfide treatment PVA was dissolved in sterile distilled water to prepare a PVA solution; CTAB was dissolved in sterile distilled water to prepare a CTAB solution; the PVA solution, CTAB solution, and iron sulfide were added to a beaker in sequence, followed by the addition of sterile distilled water. A stir bar was added inside the beaker, which was then placed on a magnetic stirrer. An external DC power supply was applied, and the carbon felt was loaded with iron sulfide at 35°C and an external voltage of 15V. After the loading was completed, the carbon felt was placed in a vacuum drying oven to dry.

[0019] (2) Cultivation and activation of sulfur autotrophic denitrifying bacteria (3) Establishment of an external DC power supply-enhanced sulfur autotrophic denitrification system The anaerobic bioreactor uses carbon felt loaded with iron sulfide as the cathode and unloaded carbon felt as the anode. Sulfate-autotrophic denitrifying bacteria are inoculated into the reactor, which is then sealed and cultured on a magnetic stirrer at 150 rpm with an external DC power supply of 0.50V. Wastewater parameters tested include nitrate nitrogen, ammonia nitrogen, nitrite nitrogen, sulfate, and pH. Example 3

[0020] A method for wastewater denitrification based on an externally powered electro-enhanced sulfur autotrophic denitrification system includes the following steps: (1) Carbon felt loaded with iron sulfide treatment PVA was dissolved in sterile distilled water to prepare a PVA solution; CTAB was dissolved in sterile distilled water to prepare a CTAB solution; the PVA solution, CTAB solution, and iron sulfide were added to a beaker in sequence, followed by the addition of sterile distilled water. A stir bar was added inside the beaker, which was then placed on a magnetic stirrer. An external DC power supply was applied, and the carbon felt was loaded with iron sulfide at 35°C and an external voltage of 15 V. After the loading was completed, the carbon felt was placed in a vacuum drying oven to dry.

[0021] (2) Cultivation and activation of sulfur autotrophic denitrifying bacteria (3) Establishment of an external DC power supply-enhanced sulfur autotrophic denitrification system The anaerobic bioreactor uses carbon felt loaded with iron sulfide as the cathode and unloaded carbon felt as the anode. Sulfate-autotrophic denitrifying bacteria are inoculated into the reactor, which is then sealed and placed on a magnetic stirrer at 150 rpm with an external DC power supply of 0.75V. Wastewater parameters tested include nitrate nitrogen, ammonia nitrogen, nitrite nitrogen, sulfate, and pH. Example 4

[0022] A method for wastewater denitrification based on an externally powered electro-enhanced sulfur autotrophic denitrification system includes the following steps: (1) Carbon felt loaded with iron sulfide treatment PVA was dissolved in sterile distilled water to prepare a PVA solution; CTAB was dissolved in sterile distilled water to prepare a CTAB solution; the PVA solution, CTAB solution, and iron sulfide were added to a beaker in sequence, followed by the addition of sterile distilled water. A stir bar was added inside the beaker, which was then placed on a magnetic stirrer. An external DC power supply was applied, and the carbon felt was loaded with iron sulfide at 35°C and an external voltage of 15 V. After the loading was completed, the carbon felt was placed in a vacuum drying oven to dry.

[0023] (2) Cultivation and activation of sulfur autotrophic denitrifying bacteria (3) Establishment of an external DC power supply-enhanced sulfur autotrophic denitrification system The anaerobic bioreactor was constructed using carbon felt loaded with iron sulfide as the cathode and unloaded carbon felt as the anode. Sulfate-autotrophic denitrifying bacteria were inoculated into the reactor, which was then sealed and placed on a magnetic stirrer at 150 rpm with a DC power supply of 1.0 V. Wastewater parameters tested included nitrate nitrogen, ammonia nitrogen, nitrite nitrogen, sulfate, and pH.

[0024] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A wastewater denitrification method based on an externally powered electro-enhanced sulfur autotrophic denitrification system, characterized in that, The method includes the following steps: The first step is the preparation of carbon felt loaded with iron sulfide. (1) The carbon felt is 2 cm*4 cm in size. Before loading, the carbon felt is soaked in concentrated nitric acid for 12 h to remove organic matter. Then it is ultrasonically cleaned with distilled water until neutral and dried in a vacuum drying oven at 60°C. (2) Dissolve PVA in sterile distilled water to prepare a PVA solution; (3) Dissolve CTAB in sterile distilled water to prepare CTAB solution; (4) PVA solution, CTAB solution and iron sulfide were added to a beaker in sequence, followed by sterile distilled water. A stir bar was added inside the beaker, and the beaker was placed on a magnetic stirrer. An external DC power supply was applied, and iron sulfide was loaded onto the carbon felt at 35°C and 15V for 1 hour. After loading, the carbon felt was placed in a vacuum drying oven to dry. The dosage of PVA was 1 g / L, the dosage of CTAB was 0.4 g / L, the dosage of iron sulfide was 4 g / L, and the solution volume during loading was 250 mL. The second step involves the cultivation and activation of sulfur-autotrophic denitrifying bacteria. The third step is to establish an external DC power supply to enhance the sulfur autotrophic denitrification system. Carbon felt loaded with iron sulfide was used as the cathode of the anaerobic bioreactor, and carbon felt unloaded with iron sulfide was used as the anode of the anaerobic bioreactor. Sulfate autotrophic denitrifying bacteria were inoculated in the reactor, and after sealing, the reactor was placed on a magnetic stirrer and cultured at a speed of 150 rpm. When denitrifying wastewater, the external DC power supply voltage is set to 0.25, 0.50, 0.75 or 1.0 V.

2. The wastewater denitrification method based on an externally powered electro-enhanced sulfur autotrophic denitrification system according to claim 1, characterized in that, In the third step of inoculating sulfur-autotrophic denitrifying bacteria, the sulfur-autotrophic denitrifying bacteria are washed with PBS and then prepared into a bacterial suspension, the OD of which is... 600 =0.03, the inoculum volume of bacterial suspension for each anaerobic reactor is 5 mL.

3. The wastewater denitrification method based on an externally powered electro-enhanced sulfur autotrophic denitrification system according to claim 1, characterized in that, The second step of the culture conditions for sulfur autotrophic denitrifying bacteria was as follows: 30℃, anaerobic; 980mL distilled water, 5g NaS2O3·5H2O, 2.0g KH2PO4, 1.7g NaNO3, 1g NaHCO3, 0.5g NH4Cl, 20.0g agar, 10mL vitamin solution, 10mL mineral solution, pH 7.0±0.2, sterilized at 121℃ for 15min.

4. The wastewater denitrification method based on an externally powered electro-enhanced sulfur autotrophic denitrification system according to claim 1, characterized in that, The second step involves culturing sulfur-autotrophic denitrifying bacteria using the following liquid culture medium: 30℃, anaerobic; 980 mL distilled water, 5 g NaS2O3·5H2O, 2.0 g KH2PO4, 1.7 g NaNO3, 1 g NaHCO3, 0.5 g NH4Cl, 10 mL vitamin solution, 10 mL mineral solution, pH 7.0±0.2, sterilized at 121℃ for 15 min.

5. The wastewater denitrification method based on an externally powered electro-enhanced sulfur autotrophic denitrification system according to claim 1, characterized in that, The second step is the activation of sulfur autotrophic denitrifying bacteria: ① Prepare 12 sulfur autotrophic denitrification liquid culture media; ② After sterilizing the surface of the test tube slant, open it in a clean bench; ③ Gently scrape the bacteria off the test tube slant with a sterile inoculation loop; ④ Place the bacteria scraped off by the inoculation loop into the liquid culture medium; ⑤ Incubate the liquid culture medium under the above culture conditions. Once the bacteria have grown, it is ready for use.

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