Method for improving acetic acid production of wet garbage by directional reinforcement of microorganisms

Abstract

This invention relates to a method for targeted enhancement of microorganisms to increase acetic acid production from wet waste, belonging to the field of environmental protection technology. This invention utilizes sulfite and ultrasound to treat wet waste, and strictly controls the sulfite dosage, ultrasound intensity and power, and pH value during anaerobic fermentation through a real-time monitoring and feedback system. This enriches functional microorganisms and directionally increases acetic acid production. This invention can increase acetic acid production by 2-4 times and the proportion of acetic acid by 2-3 times. It can maintain a high acetic acid yield during long-term continuous operation, and has advantages such as simple operation and significant increase in acetic acid production, contributing to the resource utilization of organic solid waste.

Description

Technical Field

[0001] This invention relates to the field of environmental protection technology, and in particular to a method for targeted enhancement of microorganisms to increase acetic acid production from wet waste. Background Technology

[0002] With rapid industrialization and urbanization, the output of carbohydrate-rich wet waste is increasing year by year. Improper disposal of wet waste threatens human health and ecological security, making its resource utilization a global concern. Anaerobic fermentation is a sustainable method for converting wet waste into high-value-added products (such as acetic acid). Acetic acid, as an important chemical product, has wide applications in pharmaceutical manufacturing, textile dyeing, and the rubber industry. The global market size for acetic acid is projected to exceed 20 million tons by 2025, with a price reaching $1600 per ton. Therefore, anaerobic fermentation of wet waste to synthesize acetic acid is a crucial pathway to its resource utilization.

[0003] Because wet waste contains a large amount of recalcitrant carbohydrate biomass (such as cellulose and lignin), solubilization and hydrolysis are the main rate-limiting steps affecting the acid production efficiency of anaerobic fermentation. Although existing treatment methods (such as microbial, hydrothermal, and electrocatalytic methods) can enhance the solubilization and hydrolysis efficiency of wet waste, they still face challenges such as high treatment costs, complex processes, and secondary environmental pollution. Advanced oxidation technologies based on sulfate radicals have attracted widespread attention in the treatment of recalcitrant biomass. Among them, sulfite has significant advantages over traditional persulfate and peroxymonosulfate due to its low cost and low environmental risk. Therefore, adding sulfite to the anaerobic fermentation system of wet waste is expected to enhance the solubilization and hydrolysis process. However, it is currently unclear whether sulfite oxidation can enhance the biosynthesis of acetic acid.

[0004] Meanwhile, the anaerobic fermentation process for acetic acid production, dominated by acetic acid-producing microorganisms, is a complex dynamic equilibrium process. Therefore, real-time monitoring and feedback at each stage are crucial to ensure the efficient and stable operation of the system. However, current methods focus only on optimizing and upgrading treatment technologies, lacking research on real-time monitoring and feedback mechanisms for the anaerobic fermentation process of wet waste to produce acetic acid. In particular, there are problems such as unreasonable parameters and low control precision in the selection of key process parameters and real-time feedback control. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a method for targeted enhancement of microorganisms to increase acetic acid production from wet waste. This invention utilizes sulfite and ultrasound treatment of wet waste, and strictly controls the sulfite dosage, ultrasound intensity and power, and pH value during anaerobic fermentation through a real-time monitoring and feedback system, thereby enriching functional microorganisms and targetedly increasing acetic acid production.

[0006] The purpose of this invention is to provide a method for targeted enhancement of microorganisms to increase acetic acid production from wet waste, comprising the following steps:

[0007] S1: Add wet waste into the reactor body (10), and add sulfite into the reactor body through the sulfite dosing tank (1) and electric valve (6);

[0008] S2: The sulfite concentration in the reactor body is detected by the sulfite detector (9), and the sulfite activation effect is enhanced by the ultrasonic treatment device (2) based on the sulfite concentration.

[0009] S3: Adjust the conditions of the anaerobic fermentation reaction in the main body of the reactor by means of the alkali storage tank (3) and the electric valve (7);

[0010] S4: The content of organic acids in the supernatant of the reactor effluent is detected in real time by gas chromatograph (5), and the proportion of acetic acid is calculated; the pH value of the main body of the reactor is detected by pH detector (8), and adjusted by alkali storage tank (3);

[0011] S5: Based on the acetic acid ratio, use real-time feedback to regulate the sulfite dosing tank (1) and ultrasonic treatment device (2) to control the acetic acid ratio to be no less than 60%; detect the sulfite concentration in the reactor body using the sulfite detector (9); enhance the sulfite activation effect using the ultrasonic treatment device (2) based on the detected concentration; after the reaction ends, turn off the ultrasonic treatment device (2); detect the acetic acid content.

[0012] In one embodiment of the invention, 15 wt% activated sludge from a wastewater treatment plant is added as fermentation seed sludge during the initial stage of reactor operation to acclimate acid-producing microorganisms. Once the reactor is operating stably, no further addition of microorganisms is required. The closed reactor is kept in an anaerobic state, allowing the wet waste to ferment naturally; only the sulfite content, ultrasound, and pH need to be adjusted.

[0013] In one embodiment of the present invention, the reaction apparatus for using targeted enhancement microorganisms to improve acetic acid production from wet waste is as follows:

[0014] The reaction apparatus includes a reactor body (10), a sulfite dosing tank (1), an ultrasonic treatment device (2), an alkali storage tank (3), a computer (4), a real-time gas chromatograph (5), an electric valve (6), an electric valve (7), a pH detector (8), and a sulfite detector (9).

[0015] The sulfite dosing tank (1) and the alkali storage tank (3) are connected to the inlet of the reactor body via electric valves (6) and (7), respectively; the ultrasonic treatment device (2) is evenly distributed at the bottom of the reactor body; the real-time gas chromatograph (5) detects the supernatant at the outlet of the reactor body; the pH detector (8) detects the pH of the reactor body; the pH detector (9) detects the sulfite concentration of the reactor body.

[0016] The computer (4) is connected to the ultrasonic processing device (2), the real-time gas chromatograph (5), the electric valve (6), the electric valve (7), the pH detector (8), and the sulfite detector (9), respectively.

[0017] In one embodiment of the present invention, in step S1, the total suspended solids concentration of the wet waste is 40-60 g / L.

[0018] In one embodiment of the present invention, in step S1, the amount of sulfite added is 50-150 mg / g TSS.

[0019] In one embodiment of the present invention, in step S2, the method of enhancing the activation effect of sulfite using an ultrasonic treatment device (2) according to the sulfite concentration is as follows: when the sulfite concentration is greater than 50 mg / g TSS, the ultrasonic power is 0.3-0.5 kW and the ultrasonic frequency is 40-60 kHz; when the sulfite concentration is 10-50 mg / g TSS, the ultrasonic power is 0.1-0.3 kW and the ultrasonic frequency is 20-40 kHz; when the sulfite concentration is less than 10 mg / g TSS, the ultrasonic treatment is stopped.

[0020] In one embodiment of the present invention, the sulfite is selected from sodium sulfite and / or potassium sulfite.

[0021] In one embodiment of the present invention, in step S3, the conditions for the anaerobic fermentation reaction are: pH value of 8.0-11.0, fermentation time of 6-10 days, and fermentation temperature of 25-45℃.

[0022] In one embodiment of the present invention, in step S4, the organic acid includes one or more of acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, and isovaleric acid; and / or, the acetic acid percentage refers to the ratio of the total content of acetic acid to the total content of organic acids.

[0023] In one embodiment of the present invention, step S4, detecting pH stability, is to regulate suitable conditions for anaerobic reaction and ensure efficient fermentation.

[0024] In one embodiment of the present invention, in step S5, a method for enhancing the activation effect of sulfite using an ultrasonic treatment device (2) based on the detected concentration is described below:

[0025] When the sulfite concentration is greater than 50 mg / g TSS, the ultrasonic power is 0.3-0.5 kW and the ultrasonic frequency is 40-60 kHz; when the sulfite concentration is between 10-50 mg / g TSS, the ultrasonic power is 0.1-0.3 kW and the ultrasonic frequency is 20-40 kHz; when the sulfite concentration is less than 10 mg / g TSS...

[0026] In one embodiment of the present invention, in step S5, the specific method for controlling the acetic acid ratio to be not less than 60wt% by using real-time feedback to regulate the sulfite dosing tank (1) and ultrasonic treatment device (2) according to the acetic acid ratio is as follows: when the acetic acid ratio is less than 60wt%, sulfite is added, and the amount of sulfite added is 25-75mg / g TSS.

[0027] The technical solution of the present invention has the following advantages compared with the prior art:

[0028] (1) Compared with conventional anaerobic fermentation of wet waste, this method can increase acetic acid production by 2 to 4 times and the proportion of acetic acid by 2 to 3 times. It can maintain a high acetic acid yield in a targeted manner during long-term continuous operation. It has the advantages of simple operation and significant increase in acetic acid production.

[0029] (2) Ultrasound can promote the decomposition of sulfites and their diffusion in wet waste. The generated sulfite free radicals and hydroxyl free radicals can contact the wet waste to the maximum extent, thereby accelerating the hydrolysis and solubilization efficiency of recalcitrant carbohydrate biomass, and ultimately promoting the formation of acetic acid and volatile fatty acids. Ultrasound significantly promotes the activation process of sulfites. At the same time, the ultrasonic power and frequency are matched with the sulfite concentration, enhancing its hydrolysis and solubilization efficiency of recalcitrant carbohydrate biomass, and ultimately promoting the formation of acetic acid and volatile fatty acids.

[0030] (3) The presence of sulfites significantly enriches functional microorganisms, especially sulfite-reducing bacteria, which have been found to convert propionic acid and butyric acid into acetic acid, thereby increasing the yield and ratio of acetic acid.

[0031] (4) The oxidizing power of sulfites inhibits the abundance and activity of acetic acid-consuming microorganisms such as methanogens, reduces the consumption of acetic acid during fermentation, and further increases the yield of acetic acid.

[0032] (5) The present invention can provide feedback control based on the yield and ratio of acetic acid in real time, which not only ensures the efficient and stable operation of the system, but also reduces the amount of sulfite added and the power consumption of the ultrasonic treatment device. Attached Figure Description

[0033] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein...

[0034] Figure 1 This is a schematic diagram of the device for targeted enhancement of microorganisms to increase acetic acid production from wet waste according to the present invention.

[0035] The following are the reference numerals in the accompanying drawings: 1-sulfite dosing tank, 2-ultrasonic treatment device, 3-alkali storage tank, 4-computer, 5-real-time gas chromatograph, 6-electric valve, 7-electric valve, 8-pH detector and 9-sulfite detector; 10-reactor body. Detailed Implementation

[0036] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0037] Example 1:

[0038] This embodiment provides a method for targeted enhancement of microorganisms to increase acetic acid production from wet waste, the specific steps of which are as follows:

[0039] S1: Add wet waste with a total suspended solids concentration of 50 g / L to the reactor body (10), and add sulfite to the reactor body through the sulfite dosing tank (1) and electric valve (6) at a dosage of 100 mg / g TSS;

[0040] S2: The sulfite concentration in the reactor body is detected by the sulfite detector (9). The ultrasonic treatment device (2) is used to enhance the sulfite activation effect based on the detected concentration. When the sulfite concentration is greater than 50 mg / g TSS, the ultrasonic power is 0.4 kW and the ultrasonic frequency is 50 kHz. When the sulfite concentration is between 10-50 mg / g TSS, the ultrasonic power is 0.2 kW and the ultrasonic frequency is 30 kHz. When the sulfite concentration is less than 10 mg / g TSS, the ultrasonic treatment device (2) is turned off.

[0041] S3: Adjust the pH value of the main body of the reactor to 9.5 through the alkali storage tank (3) and electric valve (7); control the anaerobic fermentation treatment temperature to 35℃; and control the wet waste retention time to 8 days;

[0042] S4: The content of organic acids in the supernatant of the reactor effluent is detected by real-time gas chromatography (5) to calculate the proportion of acetic acid; the pH value of the main body of the reactor is detected by pH detector (8);

[0043] S5: Based on the acetic acid ratio, the sulfite dosing tank (1) and ultrasonic treatment device (2) are controlled by real-time feedback to ensure that the acetic acid ratio is not less than 60%. When the acetic acid ratio is less than 60%, sulfite is added at a dosage of 50 mg / g TSS. When the sulfite concentration is greater than 50 mg / g TSS, the ultrasonic power is 0.4 kW and the ultrasonic frequency is 50 kHz. When the sulfite concentration is between 10-50 mg / g TSS, the ultrasonic power is 0.2 kW and the ultrasonic frequency is 30 kHz. When the sulfite concentration is less than 10 mg / g TSS, the ultrasonic treatment device (2) is turned off. The acetic acid content is 40584 mg COD / L, the total volatile fatty acid content is 50414 mg COD / L, and the acetic acid ratio is 80.5%.

[0044] Example 2

[0045] S1: Add wet waste with a total suspended solids concentration of 40 g / L to the reactor body (10), and add sulfite to the reactor body through the sulfite dosing tank (1) and electric valve (6) at a dosage of 50 mg / g TSS;

[0046] S2: The sulfite concentration in the reactor body is detected by the sulfite detector (9). The ultrasonic treatment device (2) is used to enhance the sulfite activation effect based on the detected concentration. When the sulfite concentration is greater than 50 mg / g TSS, the ultrasonic power is 0.3 kW and the ultrasonic frequency is 40 kHz. When the sulfite concentration is between 10-50 mg / g TSS, the ultrasonic power is 0.1 kW and the ultrasonic frequency is 20 kHz. When the sulfite concentration is less than 10 mg / g TSS, the ultrasonic treatment device (2) is turned off.

[0047] S3: Adjust the pH of the reactor body to 8.0 through the alkali storage tank (3) and electric valve (7); control the anaerobic fermentation treatment temperature to 25℃; and control the wet waste retention time to 6 days.

[0048] S4: The content of organic acids in the supernatant of the reactor effluent is detected by real-time gas chromatography (5) to calculate the proportion of acetic acid; the pH value of the main body of the reactor is detected by pH detector (8);

[0049] S5: Based on the acetic acid ratio, the sulfite dosing tank (1) and ultrasonic treatment device (2) are controlled using real-time feedback to ensure that the acetic acid ratio is not less than 60%. When the acetic acid ratio is less than 60%, sulfite is added at a dosage of 50 mg / g TSS. When the sulfite concentration is greater than 50 mg / g TSS, the ultrasonic power is 0.3 kW and the ultrasonic frequency is 40 kHz. When the sulfite concentration is between 10-50 mg / g TSS, the ultrasonic power is 0.1 kW and the ultrasonic frequency is 20 kHz. When the sulfite concentration is less than 10 mg / g TSS, the ultrasonic treatment device (2) is turned off. The acetic acid content is 35211 mg COD / L, the total volatile fatty acid content is 44969 mg COD / L, and the acetic acid ratio is 78.3%.

[0050] Example 3

[0051] S1: Add wet waste with a total suspended solids concentration of 60 g / L to the reactor body, and add sulfite to the reactor body through the sulfite dosing tank (1) and electric valve (6) at a dosage of 150 mg / g TSS;

[0052] S2: The sulfite concentration in the reactor body is detected by the sulfite detector (9). The ultrasonic treatment device (2) is used to enhance the sulfite activation effect based on the detected concentration. When the sulfite concentration is greater than 50 mg / g TSS, the ultrasonic power is 0.5 kW and the ultrasonic frequency is 60 kHz. When the sulfite concentration is between 10-50 mg / g TSS, the ultrasonic power is 0.3 kW and the ultrasonic frequency is 40 kHz. When the sulfite concentration is less than 10 mg / g TSS, the ultrasonic treatment device (2) is turned off.

[0053] S3: Adjust the pH of the main body of the reactor to 11.0 through the alkali storage tank (3) and electric valve (7); control the anaerobic fermentation treatment temperature to 45℃; and control the wet waste retention time to 10 days.

[0054] S4: The content of organic acids in the supernatant of the reactor effluent is detected by real-time gas chromatography (5) to calculate the proportion of acetic acid; the pH value of the main body of the reactor is detected by pH detector (8);

[0055] S5: Based on the acetic acid ratio, the sulfite dosing tank (1) and ultrasonic treatment device (2) are controlled using real-time feedback to ensure that the acetic acid ratio is not less than 60%. When the acetic acid ratio is less than 60%, sulfite is added at a dosage of 50 mg / g TSS. When the sulfite concentration is greater than 50 mg / g TSS, the ultrasonic power is 0.5 kW and the ultrasonic frequency is 60 kHz. When the sulfite concentration is between 10-50 mg / g TSS, the ultrasonic power is 0.3 kW and the ultrasonic frequency is 40 kHz. When the sulfite concentration is less than 10 mg / g TSS, the ultrasonic treatment device (2) is turned off. The acetic acid content is 37602 mg COD / L, the total volatile fatty acid content is 45745 mg COD / L, and the acetic acid ratio is 82.2%.

[0056] Comparative Example 1

[0057] Except for step S1, where no sulfite was added, the remaining steps were the same as in Example 1. The acetic acid content was measured at 21139 mg COD / L, the total volatile fatty acid content at 33877 mg COD / L, and the acetic acid content at 62.4%.

[0058] Compared with Comparative Example 1, Example 1 showed that the acetic acid content increased from 21139 mg COD / L to 40584 mg COD / L, an increase of 192%; the total volatile fatty acid content increased from 33877 mg COD / L to 50414 mg COD / L, an increase of 148%; and the acetic acid percentage increased from 62.4% to 80.5%, an increase of 129%.

[0059] Comparative Example 2

[0060] Except for step S2, which does not involve ultrasonic treatment, the remaining steps are the same as in Example 1. The acetic acid content was measured to be 26473 mg COD / L, the total volatile fatty acid content was 38647 mg COD / L, and the acetic acid content was 68.5%.

[0061] Compared with Comparative Example 2, Example 1 showed that the acetic acid content increased from 26473 mg COD / L to 40584 mg COD / L, an increase of 153%; the total volatile fatty acid content increased from 38647 mg COD / L to 50414 mg COD / L, an increase of 130%; and the acetic acid percentage increased from 68.5% to 80.5%, an increase of 118%.

[0062] Comparative Example 3

[0063] Except for step S5, which does not involve feedback adjustment, the remaining steps are the same as in Example 1. The acetic acid content was measured to be 29451 mg COD / L, the total volatile fatty acid content was 40566 mg COD / L, and the acetic acid content was 72.6%.

[0064] Compared with Comparative Example 3, Example 1 showed that the acetic acid content increased from 29451 mg COD / L to 40584 mg COD / L, an increase of 138%; the total volatile fatty acid content increased from 40566 mg COD / L to 50414 mg COD / L, an increase of 124%; and the acetic acid percentage increased from 72.6% to 80.5%, an increase of 111%.

[0065] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method of using directedly reinforced microorganisms for increasing acetogenesis in wet waste, characterized in that, Includes the following steps: S1: Add wet waste into the reactor body (10), and add sulfite into the reactor body through the sulfite dosing tank (1) and electric valve (6); S2: The sulfite concentration in the reactor body is detected by the sulfite detector (9), and the sulfite activation effect is enhanced by the ultrasonic treatment device (2) based on the sulfite concentration. S3: Adjust the conditions of the anaerobic fermentation reaction in the main body of the reactor by means of the alkali storage tank (3) and the electric valve (7); S4: The content of organic acids in the supernatant of the reactor effluent is detected in real time by gas chromatograph (5), and the proportion of acetic acid is calculated; the pH value of the anaerobic fermentation reaction liquid in the main body of the reactor is detected by pH detector (8), and adjusted by alkali storage tank (3); S5: Based on the acetic acid ratio, use real-time feedback to regulate the sulfite dosing tank (1) and ultrasonic treatment device (2) to control the acetic acid ratio to be no less than 60wt%; detect the sulfite concentration in the reactor body using the sulfite detector (9), and use the ultrasonic treatment device (2) to enhance the sulfite activation effect based on the detected concentration. After the reaction ends, turn off the ultrasonic treatment device (2); detect the acetic acid content. In step S1, the dosage of sulfite is 50-150 mg / g TSS; In step S2, the method of enhancing the activation effect of sulfite using an ultrasonic treatment device (2) according to the sulfite concentration is as follows: when the sulfite concentration is greater than 50 mg / g TSS, the ultrasonic power is 0.3-0.5 kW and the ultrasonic frequency is 40-60 kHz; when the sulfite concentration is 10-50 mg / g TSS, the ultrasonic power is 0.1-0.3 kW and the ultrasonic frequency is 20-40 kHz; when the sulfite concentration is less than 10 mg / g TSS, the ultrasonic treatment is stopped.

2. The method of claim 1, wherein the directedly reinforced microorganism is used to improve acetic acid production from wet waste. In step S1, the total suspended solids concentration of the wet waste is 40-60 g / L.

3. The method for using targeted enhancement microorganisms to increase acetic acid production from wet waste according to claim 1, characterized in that, The sulfite is selected from sodium sulfite and / or potassium sulfite.

4. The method of claim 1, wherein the directedly reinforced microorganism is used to increase acetic acid production from wet waste. In step S3, the conditions for the anaerobic fermentation reaction are: pH value of 8.0-11.0, fermentation time of 6-10 days, and fermentation temperature of 25-45 ℃.

5. The method of claim 1, wherein the directedly reinforced microorganism is used to increase acetic acid production from wet waste. In step S4, the organic acid includes one or more of acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, and isovaleric acid; and / or, the acetic acid percentage refers to the ratio of the total content of acetic acid to the total content of organic acids.

6. The method of claim 1, wherein the directedly reinforced microorganism is used to increase acetic acid production from wet waste. In step S5, the method of enhancing the activation effect of sulfite using an ultrasonic treatment device (2) based on the detected concentration is as follows: When the sulfite concentration is greater than 50 mg / g TSS, the ultrasonic power is 0.3-0.5 kW and the ultrasonic frequency is 40-60 kHz; when the sulfite concentration is 10-50 mg / g TSS, the ultrasonic power is 0.1-0.3 kW and the ultrasonic frequency is 20-40 kHz; when the sulfite concentration is less than 10 mg / g TSS...

7. The method of claim 1, wherein the directedly reinforced microorganism is used to increase acetic acid production from wet waste. In step S5, based on the acetic acid ratio, the method of controlling the sulfite dosing tank (1) and ultrasonic treatment device (2) to ensure that the acetic acid ratio is not less than 60wt% is as follows: when the acetic acid ratio is less than 60wt%, sulfite is added, and the amount of sulfite added is 25-75 mg / g TSS.

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