A device for bioelectrochemical treatment of soy sauce wastewater

Abstract

The present invention relates to a bioelectrochemical device for treating soy sauce wastewater and a preparation method thereof. The bioelectrochemical device comprises an anode chamber and a cathode chamber, wherein a columnar anode is disposed at the center of the anode chamber; a columnar cathode is disposed at the center of the cathode chamber; the space between the columnar anode and the anode chamber is filled with a modified conductive oxidizing filler; electroactive bacteria grow on the columnar anode and the modified conductive oxidizing filler, and the modified conductive oxidizing filler is metal-doped activated carbon. The metal-doped activated carbon is formed by mixing the activated carbon with a mixed solution of zinc sulfate and potassium sulfate, adsorbing the zinc sulfate and potassium sulfate onto the activated carbon, and then calcining the activated carbon to form corresponding metal oxides on the surface of the activated carbon. Due to the introduction of metallic potassium and metallic zinc, the metallic potassium and metallic zinc have electronic interaction and synergistic effects, thereby improving electronic conductivity and promoting degradation treatment of the soy sauce wastewater.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, in particular to a device for bioelectrochemical treatment of soy sauce wastewater. Background Art

[0002] Among the technologies for treating soy sauce wastewater, bioelectrochemical treatment methods are gradually gaining attention. Traditional soy sauce wastewater treatment technologies mainly include physical and chemical methods and biological methods. Among them, physical and chemical methods such as flocculation, precipitation, and activated carbon adsorption can effectively remove organic matter and pigments in wastewater, but these methods often require high operating costs and treatment fees. Biological methods, such as activated sludge and biofilter methods, can use microorganisms to decompose organic pollutants in wastewater. They have lower operating costs and higher treatment efficiency, but the degradation rate and treatment effect of wastewater are limited by the metabolic capacity of microorganisms and the complexity of the wastewater.

[0003] In recent years, bioelectrochemical treatment technology has shown promising prospects as an emerging wastewater treatment method. This technology combines electrochemical and biological processes, using electric current to drive biological reactions, thereby improving wastewater degradation efficiency. A typical bioelectrochemical treatment device consists of an anode chamber and a cathode chamber, with an anode located in the anode chamber and a cathode in the cathode chamber. A power supply generates an electric current between the anode and cathode, driving the biodegradation reaction of electroactive bacteria in the anode chamber, while a reduction reaction also occurs in the cathode chamber.

[0004] However, existing bioelectrochemical treatment devices still face challenges when treating soy sauce wastewater. The fillers used in traditional devices, such as activated carbon, suffer from insufficient performance. These fillers have limitations in terms of conductivity, specific surface area, and adsorption capacity. This leads to uneven growth of electroactive bacteria and low electron transfer efficiency, compromising device stability and performance, and consequently, the overall degradation effect.

[0005] Therefore, it is necessary to develop a new technical solution to address the deficiencies in the existing technology and improve the efficiency of soy sauce wastewater treatment. Summary of the Invention

[0006] Based on this, the present invention provides a bioelectrochemical treatment device for soy sauce wastewater. This device utilizes biochar formed by calcining fruit shells and silica, combined with a modified conductive oxidizing filler, to enhance the attachment and growth of electroactive bacteria, thereby effectively improving the degradation efficiency of soy sauce wastewater. These improvements aim to address shortcomings in the existing technology, enhance the overall performance of the treatment system, and overcome existing problems.

[0007] One object of the present invention is to provide a device for bioelectrochemical treatment of soy sauce wastewater, wherein the device comprises an anode chamber and a cathode chamber, wherein

[0008] A columnar anode is provided at the center of the anode chamber; a columnar cathode is provided at the center of the cathode chamber;

[0009] The space between the columnar anode and the anode chamber is filled with a modified conductive oxide filler;

[0010] Electroactive bacteria grow on the columnar anode and the modified conductive oxidizing filler;

[0011] The space between the columnar cathode and the cathode chamber is filled with a conductive reducing filler;

[0012] The columnar anode and the columnar cathode are externally connected to a power source;

[0013] The anode chamber and the cathode chamber are separated by a partition, and a water outlet A is provided at the lower end of the partition;

[0014] Soy sauce wastewater enters from the water inlet at the lower end of the anode chamber, passes through the water outlet A, and flows out from the water outlet B set at the upper end of the cathode chamber;

[0015] Wherein, the modified conductive oxide filler is metal-doped activated carbon.

[0016] Specifically, soy sauce wastewater enters the cathode chamber through the water inlet at the lower end of the anode chamber, and the wastewater overflows to the right side of the anode chamber after filling the left side of the anode chamber. The electroactive bacteria attached to and grown on the anode and the modified conductive oxidizing filler oxidize the organic matter to generate carbon dioxide, hydrogen ions, etc., and then enters the cathode chamber through the water outlet A. The wastewater fills the left side of the cathode chamber and overflows to the right side of the cathode chamber, and then flows out from the water outlet B set at the upper end of the cathode chamber; when the sewage flows through the cathode chamber, the organic ions oxidized in the anode chamber are attached to the cathode and the conductive reducing filler, generating water, hydrogen or methane and other gases for discharge, thereby achieving the effect of sewage purification.

[0017] Furthermore, the preparation method of the modified conductive oxide filler comprises the following steps:

[0018] S1. Blending silica particles with fruit shells, adding water to disperse, then filtering, and calcining the solid at high temperature to obtain activated carbon;

[0019] S2. Grind the activated carbon into particles, add the particles into a mixed solution of zinc sulfate and potassium sulfate, stir, and dry the solid. Then, heat and cool the solid in a tube furnace protected by an inert gas to obtain the metal-doped activated carbon.

[0020] Furthermore, in step S1, the calcination conditions are: 450-600° C., calcination for 60-90 min.

[0021] Furthermore, in step S2, the particle size of the activated carbon is 2-5 mm.

[0022] Furthermore, in step S2, the heating temperature is 800-900°C.

[0023] Furthermore, in step S1, the mass ratio of the silicon dioxide particles to the fruit shell is 2:1-1:0.5.

[0024] Furthermore, in step S2, the concentration of the zinc sulfate solution is 0.03-0.07 mol / L.

[0025] Furthermore, in step S2, the concentration of the potassium sulfate solution is 0.05-0.07 mol / L.

[0026] Furthermore, the conductive reducing filler is selected from graphite.

[0027] Furthermore, the electroactive bacteria are selected from one or more of the genus Geobacter, Proteiniphilum, Pseudomonas and Cloacamonas.

[0028] The present invention has the following beneficial effects:

[0029] The filler of the anode chamber in the bioelectrochemical treatment device for soy sauce wastewater provided by the present invention is a modified conductive oxide filler. The modified conductive oxide filler first forms activated carbon by calcining and carbonizing silicon dioxide particles and fruit shells, so that the silicon dioxide forms a dense, uniform and numerous porous structure on the fruit shells, thereby effectively increasing the specific surface area of the activated carbon, thereby increasing the growth space of electroactive bacteria, and being more conducive to the attachment and reproduction of electroactive bacteria. Secondly, the activated carbon is mixed with a mixed solution of zinc sulfate and potassium sulfate, and the zinc sulfate and potassium sulfate are first adsorbed on the activated carbon. Then, the activated carbon is calcined to form corresponding metal oxides on the surface of the activated carbon, thereby forming metal-doped activated carbon. Since metallic potassium and metallic zinc are introduced into the activated carbon, there is electronic interaction and synergistic effect between the metallic potassium and metallic zinc, which can improve electronic conductivity and promote the degradation treatment of soy sauce wastewater. In addition, since a large amount of metal oxide crystals are loaded on the activated carbon, the specific surface area of the activated carbon can be further increased, thereby providing a better living environment for the electroactive bacteria, being more conducive to the reproduction of the electroactive bacteria, and effectively improving the treatment capacity of soy sauce wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic structural diagram of the device for bioelectrochemical treatment of soy sauce wastewater according to the present invention.

[0031] In the figure: 1. anode chamber; 2. cathode chamber; 3. columnar anode; 4. columnar cathode; 5. modified conductive oxidizing filler; 6. conductive reducing filler; 7. power supply; 8. partition; 9. water outlet A; 10. water outlet B; 11. water inlet. DETAILED DESCRIPTION

[0032] In order to more clearly illustrate the technical solutions of the present invention, the following examples are given. Unless otherwise stated, the raw materials, reactions and post-processing methods mentioned in the examples are common raw materials on the market and technical methods well known to those skilled in the art.

[0033] The terms "preferred," "preferably," "more preferred," and the like, used herein, refer to embodiments of the invention that may provide certain benefits under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the invention.

[0034] It should be understood that, except in any operating examples, or where otherwise indicated, all numbers expressing, for example, quantities of ingredients used in the specification and claims are to be understood as being modified in all instances by the term "about." Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and appended claims are approximations that may vary depending upon the desired properties to be obtained by the present invention.

[0035] Example 1

[0036] A bioelectrochemical device for treating soy sauce wastewater, comprising an anode chamber 1 and a cathode chamber 2, wherein

[0037] A columnar anode 3 is provided at the center of the anode chamber 1; a columnar cathode 4 is provided at the center of the cathode chamber 2;

[0038] The space between the columnar anode 3 and the anode chamber 1 is filled with a modified conductive oxide filler 5, and the modified conductive oxide filler 5 is high enough to immerse the columnar anode 3;

[0039] Electroactive bacteria grow on the columnar anode 3 and the modified conductive oxide filler 5;

[0040] The space between the columnar cathode 4 and the cathode chamber 2 is filled with a conductive reducing filler 6, and the height of the conductive reducing filler 6 is sufficient to immerse the columnar cathode 4;

[0041] The columnar anode 3 and the columnar cathode 4 are externally connected to a power supply 7, and the power supply 7 connects the columnar anode 3 to the positive electrode through the anode wire, and the power supply 7 connects the columnar cathode 4 to the negative electrode through the cathode wire;

[0042] The anode chamber 1 and the cathode chamber 2 are separated by a partition 8, and a water outlet A9 is provided at the lower end of the partition 8;

[0043] The soy sauce wastewater enters the cathode chamber 2 through the water inlet 11 at the lower end of the anode chamber 1, fills the left side of the anode chamber 1, and overflows to the right side of the anode chamber 1. The electroactive bacteria attached to and grown on the columnar anode 3 and the modified conductive oxidizing filler 5 oxidize the organic matter in the soy sauce wastewater to generate carbon dioxide, hydrogen ions, etc., and then enters the cathode chamber 2 through the water outlet A9. The wastewater fills the left side of the cathode chamber 2 and overflows to the right side of the cathode chamber 2, and then flows out through the water outlet B10 provided at the upper end of the cathode chamber 2. When the sewage flows through the cathode chamber 2, the organic ions oxidized in the anode chamber 1 are attached to the cathode and the conductive reducing filler 6, generating water, hydrogen, methane and other gases for discharge.

[0044] Wherein, the modified conductive oxide filler 5 is metal-doped activated carbon;

[0045] The volume of the anode chamber 1 and the cathode chamber 2 is 7 L, the material of the columnar anode 3 is a titanium anode plate, the material of the columnar cathode 4 is a stainless steel thin film electrode cathode plate, the material of the conductive reducing filler 6 is graphite, the electroactive bacteria is Geobacter sp. (CGMCC accession number No. 1.12536), the partition 8 is an insulating plastic plate, and the water outlet A9 and the water outlet B10 are provided with a water-permeable non-woven fabric;

[0046] The preparation method of the metal-doped activated carbon is as follows:

[0047] S1-1. Dry the almond shells at 250°C, crush them, pass them through a 20-mesh sieve, soak them in a 2 wt% KOH solution at 70°C for 20 h, and filter them;

[0048] S1-2. The filtered almond shells were mixed with silicon dioxide (1:1, m / m), and then added to a sufficient amount of deionized water and stirred for dispersion. The mixture was then filtered, dried at 100° C. for 24 h, and then calcined at 500° C. for 60 min. After cooling, the mixture was washed and dried. The mixture was then immersed in a 0.5 mol / L sodium hydroxide solution for 12 h and washed until neutral. The mixture was then immersed in a 1 mol / L hydrochloric acid solution for 12 h and washed until neutral. The mixture was then dried to obtain activated carbon.

[0049] S2. Mix 0.05 mol / L zinc sulfate solution and 0.05 mol / L potassium sulfate solution (1:1, v / v) to obtain a mixed solution. Grind the activated carbon into 5 mm particles. Soak the activated carbon in the mixed solution at room temperature for 12 h (solid-to-liquid ratio of 1 g / mL). Filter and dry the solid. Then, place it in a nitrogen-protected tube furnace at 10 °C / min. -1The mixture was heated to 850° C. at a heating rate of 1000 ℃ and maintained for 3 hours, and then cooled to obtain the metal-doped activated carbon.

[0050] Example 2

[0051] A bioelectrochemical device for treating soy sauce wastewater, comprising an anode chamber 1 and a cathode chamber 2, wherein

[0052] A columnar anode 3 is provided at the center of the anode chamber 1; a columnar cathode 4 is provided at the center of the cathode chamber 2;

[0053] The space between the columnar anode 3 and the anode chamber 1 is filled with a modified conductive oxide filler 5, and the modified conductive oxide filler 5 is high enough to immerse the columnar anode 3;

[0054] Electroactive bacteria grow on the columnar anode 3 and the modified conductive oxide filler 5;

[0055] The space between the columnar cathode 4 and the cathode chamber 2 is filled with a conductive reducing filler 6, and the height of the conductive reducing filler 6 is sufficient to immerse the columnar cathode 4;

[0056] The columnar anode 3 and the columnar cathode 4 are externally connected to a power supply 7, and the power supply 7 connects the columnar anode 3 to the positive electrode through the anode wire, and the power supply 7 connects the columnar cathode 4 to the negative electrode through the cathode wire;

[0057] The anode chamber 1 and the cathode chamber 2 are separated by a partition 8, and a water outlet A9 is provided at the lower end of the partition 8;

[0058] Soy sauce wastewater enters the anode chamber 1 from the water inlet 11 at the lower end. The wastewater fills the left side of the anode chamber 1 and overflows to the right side of the anode chamber 1. The electroactive bacteria attached to and grown on the columnar anode 3 and the modified conductive oxidizing filler 5 oxidize the organic matter to generate carbon dioxide, hydrogen ions, etc., and then enters the cathode chamber 2 through the water outlet A9. The wastewater fills the left side of the cathode chamber 2 and overflows to the right side of the cathode chamber 2, and then flows out from the water outlet B10 provided at the upper end of the cathode chamber 2. When the sewage flows through the cathode chamber 2, the organic ions oxidized in the anode chamber 1 are attached to the cathode and the conductive reducing filler 6, generating water, hydrogen, methane and other gases for discharge.

[0059] Wherein, the modified conductive oxide filler 5 is metal-doped activated carbon;

[0060] The volume of the anode chamber 1 and the cathode chamber 2 is 7 L, the material of the columnar anode 3 is an Fe thin film electrode anode plate, the material of the columnar cathode 4 is a stainless steel thin film electrode cathode plate, the material of the conductive reducing filler 6 is graphite, the electroactive bacteria is Geobacter sp. (CGMCC accession number No. 1.12536), the partition 8 is an insulating plastic plate, and the water outlet A9 and the water outlet B10 are provided with a water-permeable non-woven fabric;

[0061] The preparation method of the metal-doped activated carbon is as follows:

[0062] S1-1. Dry the almond shells at 250°C, crush them, pass them through a 20-mesh sieve, soak them in a 2 wt% KOH solution at 70°C for 20 h, and filter them;

[0063] S1-2. The filtered almond shells were mixed with silicon dioxide (1:1, m / m), and then added to a sufficient amount of deionized water and stirred for dispersion. The mixture was then filtered, dried at 100° C. for 24 h, and then calcined at 500° C. for 60 min. After cooling, the mixture was washed and dried. The mixture was then immersed in a 0.5 mol / L sodium hydroxide solution for 12 h and washed until neutral. The mixture was then immersed in a 1 mol / L hydrochloric acid solution for 12 h and washed until neutral. The mixture was then dried to obtain activated carbon.

[0064] S2. Mix 0.05 mol / L zinc sulfate solution and 0.05 mol / L potassium sulfate solution (1:1, v / v) to obtain a mixed solution. Grind the activated carbon into 5 mm particles. Soak the activated carbon in the mixed solution at room temperature for 12 h (solid-to-liquid ratio of 1 g / mL). Filter and dry the solid. Then, place it in a nitrogen-protected tube furnace at 10 °C / min. -1 The mixture was heated to 850° C. at a heating rate of 1000 ℃ and maintained for 3 hours, and then cooled to obtain the metal-doped activated carbon.

[0065] Example 3

[0066] A bioelectrochemical device for treating soy sauce wastewater, comprising an anode chamber 1 and a cathode chamber 2, wherein

[0067] A columnar anode 3 is provided at the center of the anode chamber 1; a columnar cathode 4 is provided at the center of the cathode chamber 2;

[0068] The space between the columnar anode 3 and the anode chamber 1 is filled with a modified conductive oxide filler 5, and the modified conductive oxide filler 5 is high enough to immerse the columnar anode 3;

[0069] Electroactive bacteria grow on the columnar anode 3 and the modified conductive oxide filler 5;

[0070] The space between the columnar cathode 4 and the cathode chamber 2 is filled with a conductive reducing filler 6, and the height of the conductive reducing filler 6 is sufficient to immerse the columnar cathode 4;

[0071] The columnar anode 3 and the columnar cathode 4 are externally connected to a power supply 7, and the power supply 7 connects the columnar anode 3 to the positive electrode through the anode wire, and the power supply 7 connects the columnar cathode 4 to the negative electrode through the cathode wire;

[0072] The anode chamber 1 and the cathode chamber 2 are separated by a partition 8, and a water outlet A9 is provided at the lower end of the partition 8;

[0073] Soy sauce wastewater enters the anode chamber 1 from the water inlet 11 at the lower end. The wastewater fills the left side of the anode chamber 1 and overflows to the right side of the anode chamber 1. The electroactive bacteria attached to and grown on the columnar anode 3 and the modified conductive oxidizing filler 5 oxidize the organic matter to generate carbon dioxide, hydrogen ions, etc., and then enters the cathode chamber 2 through the water outlet A9. The wastewater fills the left side of the cathode chamber 2 and overflows to the right side of the cathode chamber 2, and then flows out from the water outlet B10 provided at the upper end of the cathode chamber 2. When the sewage flows through the cathode chamber 2, the organic ions oxidized in the anode chamber 1 are attached to the cathode and the conductive reducing filler 6, generating water, hydrogen, methane and other gases for discharge.

[0074] Wherein, the modified conductive oxide filler 5 is metal-doped activated carbon;

[0075] The volume of the anode chamber 1 and the cathode chamber 2 is 7 L. The material of the columnar anode 3 is an Fe thin film electrode anode plate, the material of the columnar cathode 4 is a stainless steel thin film electrode cathode plate, the material of the conductive reducing filler 6 is graphite, the electroactive bacteria are Pseudomonas sp. (CCTCC AB 2012838), the partition 8 is an insulating plastic plate, and the water outlet A9 and the water outlet B10 are provided with a water-permeable non-woven fabric;

[0076] The preparation method of the metal-doped activated carbon is as follows:

[0077] S1-1. Dry the almond shells at 250°C, crush them, pass them through a 20-mesh sieve, soak them in a 2 wt% KOH solution at 70°C for 20 h, and filter them;

[0078] S1-2. The filtered almond shells were mixed with silicon dioxide (1:1, m / m), and then added to a sufficient amount of deionized water and stirred for dispersion. The mixture was then filtered, dried at 100° C. for 24 h, and then calcined at 500° C. for 60 min. After cooling, the mixture was washed and dried. The mixture was then immersed in a 0.5 mol / L sodium hydroxide solution for 12 h and washed until neutral. The mixture was then immersed in a 1 mol / L hydrochloric acid solution for 12 h and washed until neutral. The mixture was then dried to obtain activated carbon.

[0079] S2. Mix 0.05 mol / L zinc sulfate solution and 0.05 mol / L potassium sulfate solution (1:1, v / v) to obtain a mixed solution. Grind the activated carbon into 5 mm particles. Soak the activated carbon in the mixed solution at room temperature for 12 h (solid-to-liquid ratio of 1 g / mL). Filter and dry the solid. Then, place it in a nitrogen-protected tube furnace at 10 °C / min. -1 The mixture was heated to 850° C. at a heating rate of 1000 ℃ and maintained for 3 hours, and then cooled to obtain the metal-doped activated carbon.

[0080] Comparative Example 1

[0081] A device for bioelectrochemical treatment of soy sauce wastewater. The difference between this comparative example and Example 1 is that the silicon dioxide in step S1-2 is removed and replaced by almond shells of equal mass. Other ingredients and preparation methods are the same as those in Example 1.

[0082] Comparative Example 2

[0083] A device for bioelectrochemical treatment of soy sauce wastewater. The difference between this comparative example and Example 1 is that in step S2, an equal volume of 0.05 mol / L zinc sulfate solution is used to replace the 0.05 mol / L potassium sulfate solution. Other components and preparation methods are the same as those in Example 1.

[0084] Test Case

[0085] The performance tests were conducted on the bioelectrochemical treatment devices for soy sauce wastewater prepared in Example 1 and Comparative Examples 1-2.

[0086] The test method is as follows:

[0087] Soy sauce wastewater with a COD value of 1230 mg / L, an ammonia nitrogen concentration of 140 mg / L, and a pH of 7 was added from the water inlet to the bioelectrochemical treatment devices for soy sauce wastewater prepared in Example 1 and Comparative Examples 1-2, respectively. The output voltage of the power supply was 1.2-1.6 V, and the current density was controlled to be 0.03 mA / cm 2 , control the hydraulic retention time to 5h, and measure the COD and ammonia nitrogen concentrations of the treated soy sauce wastewater.

[0088] The test results are shown in Table 1.

[0089] Table 1 Performance test results

[0090] project Example 1 Comparative Example 1 Comparative Example 2 COD (mg / L) 88 192 137 Ammonia nitrogen concentration (mg / L) 7 23 18

[0091] It can be seen from Table 1 that the bioelectrochemical treatment device for soy sauce wastewater of the present invention has excellent wastewater treatment capacity and good performance, and solves the defects existing in the prior art.

[0092] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

[0093] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A device for bioelectrochemical treatment of soy sauce wastewater, characterized in that: The bioelectrochemical device for treating soy sauce wastewater comprises an anode chamber and a cathode chamber, wherein A columnar anode is provided at the center of the anode chamber; a columnar cathode is provided at the center of the cathode chamber; The space between the columnar anode and the anode chamber is filled with a modified conductive oxide filler; Electroactive bacteria grow on the columnar anode and the modified conductive oxidizing filler; The space between the columnar cathode and the cathode chamber is filled with a conductive reducing filler; The columnar anode and the columnar cathode are externally connected to a power source; The anode chamber and the cathode chamber are separated by a partition, and a water outlet A is provided at the lower end of the partition; Soy sauce wastewater enters from the water inlet at the lower end of the anode chamber, passes through the water outlet A, and flows out from the water outlet B set at the upper end of the cathode chamber; Wherein, the modified conductive oxide filler is metal-doped activated carbon; The preparation method of the modified conductive oxide filler comprises the following steps: S1. Blending silica particles with fruit shells, adding water to disperse, then filtering, and calcining the solid at high temperature to obtain activated carbon; S2. Grind the activated carbon into particles, add the particles into a mixed solution of zinc sulfate and potassium sulfate, stir, and dry the solid. Then, heat and cool the solid in a tube furnace protected by an inert gas to obtain the metal-doped activated carbon.

2. The device for bioelectrochemical treatment of soy sauce wastewater according to claim 1, characterized in that: In step S1, the calcination conditions are: 450-600° C., calcination for 60-90 min.

3. The device for bioelectrochemical treatment of soy sauce wastewater according to claim 1, characterized in that: In step S1, the mass ratio of the silicon dioxide particles to the fruit shell is 2:1-1:0.

5.

4. The device for bioelectrochemical treatment of soy sauce wastewater according to claim 1, characterized in that: In step S2, the particle size of the activated carbon is 2-5 mm.

5. The device for bioelectrochemical treatment of soy sauce wastewater according to claim 1, characterized in that: In step S2, the heating temperature is 800-900°C.

6. The device for bioelectrochemical treatment of soy sauce wastewater according to claim 1, characterized in that: In step S2, the concentration of the zinc sulfate solution is 0.03-0.07 mol / L.

7. The device for bioelectrochemical treatment of soy sauce wastewater according to claim 1, characterized in that: In step S2, the concentration of the potassium sulfate solution is 0.05-0.07 mol / L.

8. The device for bioelectrochemical treatment of soy sauce wastewater according to claim 1, characterized in that: The conductive reducing filler is selected from graphite.

9. The device for bioelectrochemical treatment of soy sauce wastewater according to claim 1, characterized in that: The electroactive bacteria are selected from one or more of the genus Geobacter, Proteophilic Bacteria, Pseudomonas and anaerobic ammonia oxidizing bacteria.

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