Directional acetic acid fermentation device and method for kitchen waste with lactic acid as intermediate

Abstract

The invention relates to the field of waste treatment and recycling, and discloses a kitchen waste directional acetic acid fermentation device and method with lactic acid as an intermediate, the kitchen waste directional acetic acid fermentation device comprises an acetic acid fermentation chamber, a lactic acid fermentation chamber is arranged in the acetic acid fermentation chamber, the top of the lactic acid fermentation chamber is provided with a lactic acid fermentation chamber water inlet, and the side wall of the lactic acid fermentation chamber is provided with a permeable membrane; lactic acid generated in the lactic acid fermentation chamber can enter the acetic acid fermentation chamber through the permeable membrane, an acetic acid fermentation chamber product water outlet is formed in the bottom of the acetic acid fermentation chamber, and the acetic acid fermentation chamber is further connected with a circulation system used for circulating liquid in the acetic acid fermentation chamber. The method can solve the problem that the kitchen waste is difficult to directionally recover, realizes directional acetic acid resource recovery of complex organic matters, and has multiple advantages of economy, environmental protection, resource reutilization and the like.

Description

Technical Field

[0001] The present invention relates to the field of waste treatment and resource utilization, and in particular to a device and method for directional acetic acid fermentation of kitchen waste using lactic acid as an intermediate. Background Art

[0002] Current food waste disposal methods, such as landfill, composting, and incineration, are generally subject to environmental pollution. While anaerobic digestion offers significant environmental benefits, it requires complex technology and equipment, resulting in high operational and maintenance costs. The stringent requirements for the storage and transportation of methane gas, in particular, further drive up costs. Therefore, there is an urgent need to explore new, environmentally friendly, cost-effective approaches to food waste disposal and resource utilization to address this significant challenge.

[0003] Acetic acid is a widely used organic acid in a wide range of industries, including food, pharmaceuticals, and chemicals. Its primary production method is chemical synthesis, which presents complex technical requirements, harsh reaction conditions, and numerous byproducts. Bio-based acetic acid production converts organic matter into acetic acid through microbial fermentation. Its raw materials include food industry byproducts and agricultural waste, enabling both organic waste treatment and resource recovery.

[0004] However, limited research is currently underway on bio-based acetic acid production. The acetic acid produced directly by fermentation with Acetobacter aceticum is generally of low purity and requires a long fermentation cycle. Therefore, achieving targeted acetic acid conversion from food waste and shortening fermentation time are key challenges in bio-based acetic acid production. Summary of the Invention

[0005] To solve the problems existing in the prior art, the present invention provides a device and method for the targeted acetic acid fermentation of food waste using lactic acid as an intermediate. The present invention first uses a lactic acid bacteria group to perform lactic acid fermentation on food waste, and then performs acetic acid fermentation using lactic acid as a substrate, thereby achieving the treatment and acetic acidization of food waste, which can realize organic waste treatment and resource recovery.

[0006] To achieve the above object, the specific technical solutions adopted in the present invention are as follows: A device for directional acetic acid fermentation of kitchen waste using lactic acid as an intermediate comprises an acetic acid fermentation chamber, wherein a lactic acid fermentation chamber is provided in the acetic acid fermentation chamber, a water inlet for the lactic acid fermentation chamber is provided at the top of the lactic acid fermentation chamber, a permeable membrane is provided on the side wall of the lactic acid fermentation chamber, and the permeable membrane enables lactic acid generated in the lactic acid fermentation chamber to enter the acetic acid fermentation chamber, a water outlet for the acetic acid fermentation chamber product is provided at the bottom of the acetic acid fermentation chamber, and the acetic acid fermentation chamber is further connected to a circulation system for circulating liquid in the acetic acid fermentation chamber.

[0007] Preferably, the lactic acid fermentation chamber is provided with a stirrer for stirring the liquid in the lactic acid fermentation chamber.

[0008] Preferably, the inner wall of the acetic acid fermentation chamber is provided with a temperature control layer for controlling the temperature of the liquid in the acetic acid fermentation chamber.

[0009] Preferably, the temperature control layer adopts a cylindrical structure with a cavity interlayer and no upper bottom. The outer wall of the temperature control layer is attached to the inner wall of the acetic acid fermentation chamber. The inner cavity of the temperature control layer is used to hold liquid. The lactic acid fermentation chamber is located in the inner cavity of the temperature control layer. The temperature control layer is connected to a temperature control layer water inlet and a temperature control layer water outlet that are in communication with the inner cavity of the cavity interlayer of the temperature control layer. The water inlet of the temperature control layer is connected to a circulating flow pump II and an electric valve V.

[0010] Preferably, the circulation system includes a circulation pipeline, one end of which is connected to the bottom of the inner cavity of the acetic acid fermentation chamber and the other end is arranged at the top of the acetic acid fermentation chamber. The circulation pipeline is sequentially provided with an electric valve II, a pH detector and a circulation flow pump I.

[0011] Preferably, an external pipeline is connected between the pH detector and the circulation flow pump I on the circulation pipeline, and an electric valve IV is provided on the external pipeline.

[0012] Preferably, an electric valve I is provided on the water inlet of the lactic acid fermentation chamber, and an electric valve III is provided on the product water outlet of the acetic acid fermentation chamber. The acetic acid fermentation chamber and the lactic acid fermentation chamber are both cylindrical in shape and coaxially arranged. The outer diameter of the lactic acid fermentation chamber is smaller than the inner diameter of the acetic acid fermentation chamber, and the height of the lactic acid fermentation chamber is smaller than the height of the acetic acid fermentation chamber. The inner cavity of the acetic acid fermentation chamber is provided with a temperature sensor for detecting the temperature of the liquid in the acetic acid fermentation chamber.

[0013] The present invention also provides a method for the directed acetic acid fermentation of food waste using lactic acid as an intermediate. The method is carried out using the device for the directed acetic acid fermentation of food waste using lactic acid as an intermediate as described above. The method comprises: Fe3O4 powder is added to the lactic acid fermentation chamber, and a mixed liquid of food waste is introduced into the lactic acid fermentation chamber until the liquid level in the lactic acid fermentation chamber and the acetic acid fermentation chamber is higher than the top height of the permeable membrane; wherein the mixed liquid of food waste is obtained by diluting the food waste with water; Then, respective activated seed solutions were inoculated in the lactic acid fermentation chamber and the acetic acid fermentation chamber, wherein the activated seed solution inoculated in the lactic acid fermentation chamber was obtained by inoculating a lactic acid bacteria mass formed by immobilized Lactobacillus rhamnosus and Rhizopus into a sterilized MRS medium and culturing the same; and the activated seed solution inoculated in the acetic acid fermentation chamber was obtained by inoculating an immobilized Acetobacter mass into a sterilized GYP medium and culturing the same; After the activated seed liquid is inoculated, fermentation is carried out using a sequencing batch operation method: in the lactic acid fermentation chamber, the food waste is hydrolyzed by Rhizopus, and Lactobacillus rhamnosus uses the hydrolysis area to generate lactic acid, thereby achieving lactic acidification of the food waste; the lactic acid generated in the lactic acid fermentation chamber enters the acetic acid fermentation chamber through a permeable membrane, and in the acetic acid fermentation chamber, the lactic acid is acted upon by acetic bacteria to generate acetic acid, and the generated acetic acid is discharged through the product outlet of the acetic acid fermentation chamber.

[0014] Preferably: in the lactic acid fermentation chamber, the concentration of Fe3O4 powder is 8-12 g / L, and the particle size of Fe3O4 powder is not greater than 0.2 mm; When inoculating the respective activated seed liquids in the lactic acid fermentation chamber and the acetic acid fermentation chamber, the activated seed liquids are inoculated at an inoculation ratio of 4.5%-5.5% by volume; after inoculating the respective activated seed liquids in the lactic acid fermentation chamber and the acetic acid fermentation chamber, the pH values ​​in the lactic acid fermentation chamber and the acetic acid fermentation chamber are adjusted and controlled to be maintained at 5.0-5.5, and then the supernatants in the lactic acid fermentation chamber and the acetic acid fermentation chamber are taken at preset time intervals to detect the concentrations of the components of each fermentation liquid until the component concentrations do not change, and the inoculation start-up of the device is completed.

[0015] Preferably, the total solid mass fraction in the mixed liquor of food waste is 5.5%-6.5%.

[0016] The present invention has the following beneficial effects: The directional acetic acid fermentation device of the present invention comprises a lactic acid fermentation chamber water inlet and an acetic acid fermentation product water outlet. During use, a food waste mixture diluted with water is introduced into the lactic acid fermentation chamber through the lactic acid fermentation chamber water inlet, so that the liquid level is higher than the top of the permeable membrane on the wall of the lactic acid fermentation chamber. Lactic acid produced by lactic acid fermentation of the food waste enters the acetic acid fermentation chamber through the permeable membrane, thereby achieving lactic acidification of the food waste. Under the promotion of Fe3O4, the acetic acid bacteria group uses lactic acid as a substrate to produce directional acetic acid, which is discharged through the water outlet provided in the acetic acid fermentation chamber, thereby achieving acetic acid production. As described above, the acetic acid fermentation device of the present invention can achieve food waste treatment. The acetic acid fermentation of food waste using lactic acid as an intermediate and Fe3O4 as a promoter improves the fermentation purity and yield of acetic acid, thereby achieving directional resource utilization of food waste. The directional acetic acid fermentation device of the present invention can also achieve the treatment of food industry byproducts and agricultural waste and directional acetic acid resource utilization, and has the characteristics of universal economic and environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic structural diagram of a device for directional acetic acid fermentation of food waste using lactic acid as an intermediate according to the present invention; Figure 22. It is a top view of the device for directional acetic acid fermentation of food waste using lactic acid as an intermediate according to the present invention; Figure 3 yes Figure 1 AA´ cross-section diagram; In the figure: 1-electric valve I, 2-lactic acid fermentation chamber water inlet, 3-temperature sensor, 4-bolt, 5-annular flange gasket, 6-temperature control layer water outlet, 7-permeable membrane, 8-insulation layer, 9-immobilized lactic acid bacteria group, 10-agitator, 11-temperature control layer, 12-immobilized acetic acid bacteria group, 13-electric valve II, 14-circulation flow pump I, 15-pH detector, 16-electric valve III, 17-acetic acid fermentation chamber product water outlet, 18-electric valve IV, 19-circulation pipeline, 20-external pipeline, 21-temperature control layer water inlet, 22-circulation flow pump II, 23-electric valve V. DETAILED DESCRIPTION

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Unless otherwise specified or conflicting, the preferred embodiments may be combined arbitrarily.

[0019] See also Figure 1-Figure 3 The present embodiment provides a device for the directed acetic acid fermentation of food waste using lactic acid as an intermediate, including an acetic acid fermentation chamber, wherein a lactic acid fermentation chamber is provided in the acetic acid fermentation chamber. A lactic acid fermentation chamber water inlet 2 is provided at the top of the lactic acid fermentation chamber, and a permeable membrane 7 is provided on the side wall of the lactic acid fermentation chamber. The permeable membrane 7 allows the lactic acid generated in the lactic acid fermentation chamber to enter the acetic acid fermentation chamber. An acetic acid fermentation chamber product water outlet 17 is provided at the bottom of the acetic acid fermentation chamber. The acetic acid fermentation chamber is also connected to a circulation system for circulating the liquid in the acetic acid fermentation chamber.

[0020] The method for directional acetic acid fermentation of kitchen waste using lactic acid as an intermediate using the fermentation device of the above embodiment of the present invention includes the following steps: Fe3O4 powder is added to the lactic acid fermentation chamber, and a mixed liquid of food waste is introduced into the lactic acid fermentation chamber until the liquid level in the lactic acid fermentation chamber and the acetic acid fermentation chamber is higher than the top height of the permeable membrane 7; wherein the mixed liquid of food waste is obtained by diluting the food waste with water; Then, respective activated seed solutions were inoculated in the lactic acid fermentation chamber and the acetic acid fermentation chamber, wherein the activated seed solution inoculated in the lactic acid fermentation chamber was obtained by inoculating a lactic acid bacteria mass formed by immobilized Lactobacillus rhamnosus and Rhizopus into a sterilized MRS medium and culturing the same; and the activated seed solution inoculated in the acetic acid fermentation chamber was obtained by inoculating an immobilized Acetobacter mass into a sterilized GYP medium and culturing the same; After the activated seed liquid is inoculated, fermentation is carried out using a sequencing batch operation method: in the lactic acid fermentation chamber, the food waste is hydrolyzed under the action of Rhizopus, and Lactobacillus rhamnosus uses the hydrolysis area to generate lactic acid, thereby achieving lactic acidification of the food waste; the lactic acid generated in the lactic acid fermentation chamber enters the acetic acid fermentation chamber through the permeable membrane 7, and in the acetic acid fermentation chamber, the lactic acid is acted upon by acetic bacteria to generate acetic acid, and the generated acetic acid is passed through the acetic acid fermentation chamber product outlet 17.

[0021] In the above scheme, the total solid mass fraction of the food waste mixture is 5.5%-6.5%; in the lactic acid fermentation chamber, the concentration of Fe3O4 powder is 8-12g / L, and the particle size of Fe3O4 powder is not greater than 0.2mm; when the respective activated seed liquids are inoculated in the lactic acid fermentation chamber and the acetic acid fermentation chamber, the activated seed liquids are inoculated at an inoculation ratio of 4.5%-5.5% by volume; after the respective activated seed liquids are inoculated in the lactic acid fermentation chamber and the acetic acid fermentation chamber, the pH values ​​in the lactic acid fermentation chamber and the lactic acid fermentation chamber are adjusted and controlled to be maintained at 5.0-5.5, and then the supernatant in the lactic acid fermentation chamber and the acetic acid fermentation chamber is taken at preset time intervals to detect the concentration of each fermentation liquid component until the component concentration does not change, and the inoculation start-up of the device is completed.

[0022] As a preferred embodiment of the present invention, see Figure 1-Figure 3 In this embodiment, a stirrer 10 is provided in the lactic acid fermentation chamber for stirring the liquid in the lactic acid fermentation chamber. The stirrer 10 can make the liquid in the lactic acid fermentation chamber mixed evenly, which is beneficial to improving the mass transfer rate and reaction rate in the lactic acid fermentation chamber.

[0023] As a preferred embodiment of the present invention, in this example, a temperature control layer 11 is installed on the inner wall of the acetic acid fermentation chamber to control the temperature of the liquid within the chamber. This temperature control layer 11 controls the temperature of the liquid within the acetic acid fermentation chamber. This, in turn, controls the temperature of the liquid within the lactic acid fermentation chamber by heating the liquid within the acetic acid fermentation chamber in a water bath. This helps ensure that each bacterial species reacts at the desired temperature, improving reaction efficiency and controlling the types of reaction products. Specifically, the liquid temperature within both the acetic acid fermentation chamber and the lactic acid fermentation chamber can be controlled at 36-38°C, achieving the aforementioned effects.

[0024] As a preferred embodiment of the present invention, in this embodiment, the temperature control layer 11 can specifically adopt the following structure. Specifically, the temperature control layer 11 can adopt a cylindrical structure with a hollow interlayer and no upper bottom (although a removable upper cover can be provided to maintain the reaction environment required by the entire device, but the upper cover is not part of the structure of the temperature control layer 11 itself). The outer wall of the temperature control layer 11 is attached to the inner wall of the acetic acid fermentation chamber, and the inner cavity of the temperature control layer 11 serves as the inner cavity of the acetic acid fermentation chamber for holding the liquid required by the acetic acid fermentation chamber. The lactic acid fermentation chamber is located in the inner cavity of the temperature control layer 11. The temperature control layer 11 is connected to a temperature control layer water inlet 21 and a temperature control layer water outlet 6, which are connected to the inner cavity of the hollow interlayer of the temperature control layer 11. The temperature control layer water inlet 21 is connected to a circulation flow pump II 22 and an electric valve V 23. In specific implementation, the temperature control layer water inlet 21 is set at the bottom of the temperature control layer 11, the temperature control layer water outlet 6 is set at the top of the temperature control layer 11, and the temperature control layer water outlet 6 is as far away from the temperature control layer water inlet 21 as possible (such as Figure 1 As shown, the temperature control layer water outlet 6 is located on the opposite side of the temperature control layer water inlet 21. A heat exchange medium (such as water) can be introduced from the temperature control layer water inlet 21 into the cavity interlayer of the temperature control layer 11 via a circulating flow pump II 22. The temperature control layer 11 can be made of a metal with heat conduction and heating capabilities (such as copper, iron, aluminum, or their corresponding alloys). This heat conduction heats the liquid within the temperature control layer 11. Simultaneously, an electric valve V 23 can control the flow rate at the temperature control layer water inlet 21, thereby achieving temperature control.

[0025] In addition, a heat preservation layer 8 may be provided outside the temperature control layer 11 to keep the temperature control layer 11 warm. In this case, the heat preservation layer 8 may be provided outside the temperature control layer 11 to form an acetic acid fermentation chamber.

[0026] As a preferred embodiment of the present invention, see Figure 1-Figure 3 In this embodiment, the circulation system includes a circulation line 19, one end of which is connected to the bottom of the acetic acid fermentation chamber interior and the other end is located at the top of the chamber. Circulation line 19 is sequentially provided with an electric valve II 13, a pH meter 15, and a circulation flow pump I 14. During operation, circulation flow pump I 14 draws liquid from the bottom of the acetic acid fermentation chamber interior and transports it to the top of the chamber via circulation line 19, thereby achieving a circulating mass transfer of the liquid within the acetic acid fermentation chamber and helping to increase reaction efficiency. The circulation speed can be adjusted using electric valve II 13, and the pH meter 15 monitors the pH value of the liquid within the acetic acid fermentation chamber in real time to ensure that all reactions proceed within a preset pH range.

[0027] As a preferred embodiment of the present invention, based on the above-described embodiment, in this embodiment, an external pipe 20 is connected to the circulation line 19 between the pH detector 15 and the circulation flow pump I 14. External pipe 20 is equipped with an electric valve IV 18. External pipe 20 can be used to replenish or drain liquid from the acetic acid fermentation chamber and can also be used to deliver pH-adjusting chemicals to maintain the pH value of the liquid in the acetic acid fermentation chamber within a preset range. Electric valve IV 18 controls the flow rate of the liquid through external pipe 20.

[0028] As a preferred embodiment of the present invention, based on the above embodiment, in this embodiment, an electric valve I1 is provided at the water inlet 2 of the lactic acid fermentation chamber, and an electric valve III 16 is provided at the product water outlet 17 of the acetic acid fermentation chamber. The flow rates of the water inlet 2 of the lactic acid fermentation chamber and the product water outlet 17 of the acetic acid fermentation chamber can be controlled by the electric valve I1 and the electric valve III 16, respectively. The acetic acid fermentation chamber and the lactic acid fermentation chamber are both cylindrical in shape and coaxially arranged. The outer diameter of the lactic acid fermentation chamber is smaller than the inner diameter of the acetic acid fermentation chamber, and the height of the lactic acid fermentation chamber is smaller than the height of the acetic acid fermentation chamber. The inner cavity of the acetic acid fermentation chamber is provided with a temperature sensor 3 for detecting the temperature of the liquid in the acetic acid fermentation chamber.

[0029] Example 1 Reference Figure 1 The present embodiment provides a device for directional acetic acid fermentation of kitchen waste using lactic acid as an intermediate, comprising a lactic acid fermentation chamber, an acetic acid fermentation chamber, a temperature control system, a pH detection system, and a control panel. The main control panel is arranged outside the device. An annular flange cover is provided on the top of the lactic acid fermentation chamber and the acetic acid fermentation chamber. The annular flange cover is divided into two layers, the center of the upper annular flange cover is connected to the top of the lactic acid fermentation chamber, and the lower annular flange cover is connected to the outer edge of the acetic acid fermentation chamber. An annular flange gasket 5 is provided at the edge between the upper annular flange cover and the lower annular flange cover. The edges of the upper annular flange cover and the lower annular flange cover are sealed and fixed by bolts 4. The inner radius of the upper layer of the annular flange cover is the same as the radius of the top cover of the lactic acid fermentation chamber, and the radius of the lower layer is the same as that of the lactic acid fermentation chamber. The lactic acid bacteria fermentation chamber is provided with a top cover, and rubber pads are provided on the outer edge and bottom of the top cover. The top cover of the lactic acid fermentation chamber is threadedly connected to the chamber body, so that the lactic acid fermentation chamber is fixed at the center and upper position of the acetic acid fermentation chamber. The top cover of the lactic acid fermentation chamber is embedded in the inner circle, with a rubber pad underneath. The top cover of the lactic acid fermentation chamber is provided with a water inlet 2. The interior of the lactic acid fermentation chamber is provided with an immobilized lactic acid-producing bacteria group 9 and a stirrer 10. The water inlet 2 of the lactic acid fermentation chamber is provided with an electric valve I 1. The wall of the lactic acid fermentation chamber is provided with a permeable membrane 7, which is below the fermentation substrate liquid level. The acetic acid fermentation chamber is provided with a top cover, a temperature sensor 3, a circulation pipeline 19, an immobilized acetic acid bacteria group 12, and an acetic acid fermentation chamber product outlet 17 in order from top to bottom. The circulation pipeline 19 is provided with an electric valve II 13, a pH detector 15, a circulation flow pump I 14, and an electric valve III 16 at the outlet end. The acetic acid fermentation chamber is provided with a temperature control system, which includes a temperature control layer 11, a water outlet 6 of the temperature control layer, a water inlet 21 of the temperature control layer, a temperature control layer insulation layer 8 and a temperature sensor 3. A refrigerant is provided in the temperature control layer 11 for temperature control, and the water inlet is connected to an external refrigerant. A circulating flow pump II 22 and an electric valve V 23 are provided. The temperature sensor 3, the circulating flow pump II 22 and the electric valve V 23 are connected to the control panel via electrical signals. A circulation pipeline 19 is provided outside the acetic acid fermentation chamber. The circulation pipeline 19 is provided with an electric valve II 13, a pH detector 15, a circulation flow pump I1 4 and an external pipeline 20. The external pipeline 20 is connected to 0.1 mol / L NaOH and is provided with an electric valve IV 18. The electric valve II 13, the pH detector 15 and the electric valve IV 18 are connected to the control panel through electrical signals.

[0030] Reference Figure 1 、 Figure 2 and Figure 3 In this embodiment, the effective height-to-diameter ratio of the lactic acid fermentation chamber is 1:1 (effective height = liquid level elevation - fermentation chamber bottom elevation), the outer wall diameter ratio of the lactic acid fermentation chamber and the acetic acid fermentation chamber is 1:1.3, and the effective height ratio of the lactic acid fermentation chamber and the acetic acid fermentation chamber is 1:1.2; A stirrer 10 is provided in the lactic acid fermentation chamber, and anaerobic fermentation is performed under the action of the stirrer 10. The rotation speed of the spiral stirrer is 150-200 rpm.

[0031] The method for treating kitchen waste and producing acetic acid in this embodiment is carried out using the above-mentioned kitchen waste directional acetic acid fermentation device using lactic acid as an intermediate, and the process is as follows: Step 1: The device is equipped with a pH detector and an automatic valve to control the pH inside the device to 5. The device is also equipped with a temperature sensor, a flow pump and an electric valve V to control the temperature inside the device to 36-38°C; Step 2: Inoculate the immobilized "Lactobacillus rhamnosus + Rhizopus" lactic acid bacteria group and the immobilized Acetobacter group into the sterilized MRS medium and GYP medium at a concentration of 3 g / L, respectively, and culture for 24 hours. Pre-add 10 g / L Fe3O4 powder (particle size ≤ 0.2 mm) to the acetic acid fermentation chamber, introduce a certain amount of food waste mixture into the reactor, and then inoculate the cultured activated seed liquid into each fermentation chamber at an inoculation ratio of 5% (volume fraction). Adjust and control the pH to 5.0, operate the reactor for several days, and take the supernatant every 12 hours to detect the concentration of each component of the fermentation liquid until the concentration no longer changes, and the inoculation start-up of the device is completed.

[0032] Step 3: The fermentation process of this device adopts a sequencing batch operation, diluting the food waste to control the total solids (TS) mass fraction to 6% ± 0.5%. The food waste mixture is introduced into the lactic acid fermentation chamber through the water inlet, so that the effective height of the food waste mixture in the lactic acid fermentation chamber is equal to its diameter, and the pH in the device is adjusted to 5.0. The food waste is hydrolyzed into small molecular organic substances such as reducing sugars and amino acids under the action of Rhizopus. Lactobacillus rhamnosus uses the small molecular organic substances to generate lactic acid, thereby achieving lactic acidification of the food waste. The generated lactic acid enters the acetic acid fermentation chamber through the permeable membrane, and is acted upon by acetic bacteria to generate acetic acid, which is discharged through the water outlet 17. Step 4. When the device is finished running, close the electric valve I 1, the electric valve III 16, the electric valve II 13 and the circulation flow pump I 14, stop feeding, turn off the agitator 10, take out the lactic acid fermentation chamber as a whole, open the top cover of the lactic acid fermentation chamber, rinse the lactic acid and acetic acid fermentation chambers with clean water, reinstall the device, open the electric valve I 1, pass clean water to the top of the permeable membrane 7, turn on the agitator 10, the electric valve II 13 and the circulation flow pump I 14, run stably for 1 hour, thoroughly clean the circulation pipeline 19, close the electric valve I 1, the agitator 10, the electric valve II 13 and the circulation flow pump I 14, and complete the termination of the device.

[0033] Example 2 like Figures 1 to 3 As shown, in the directional acetic acid fermentation device for food waste using lactic acid as an intermediate in this embodiment, the sizes and proportions of the various components can be set according to actual conditions. In this embodiment, the effective height-to-diameter ratio of the lactic acid fermentation chamber is 1:1 (effective height = liquid level elevation - fermentation chamber bottom elevation), the outer wall diameter ratio of the lactic acid fermentation chamber and the acetic acid fermentation chamber is 1:1.3, and the effective height ratio of the lactic acid fermentation chamber and the acetic acid fermentation chamber is 1:1.2. The water outlet 17 of the acetic acid fermentation chamber is 1 / 10 of the total height from the bottom of the fermentation chamber, the headspace of the lactic acid fermentation chamber accounts for 33.3%, and the headspace of the acetic acid fermentation chamber accounts for 25.1%. The permeable membrane 7 is square with a height-to-width ratio of 1:1, and the ratio of the surface area of ​​the permeable membrane to the total volume of the lactic acid fermentation chamber is 1 cm 2 :60cm3 The thickness of the temperature control layer 11 is 3 / 10 of the diameter of the lactic acid fermentation chamber, and the thickness ratio of the temperature control layer 11 to the insulation layer 8 is 1:1. After testing, the above dimensions and ratios can better achieve the experimental purpose of the present invention.

[0034] In this embodiment, the device for directional acetic acid fermentation of food waste using lactic acid as an intermediate is made of organic glass, and its working process is as follows: The device adopts a sequencing batch operation to mix food waste and tap water, controlling the total solids (TS) mass fraction to 6%±0.5%. The food waste mixture is introduced into the lactic acid fermentation chamber through the water inlet 2 so that the effective height of the food waste mixture in the lactic acid fermentation chamber is equal to its diameter, and the pH in the device is adjusted to 5. The food waste is hydrolyzed into small molecular organic substances such as reducing sugars and amino acids under the action of Rhizopus. Lactobacillus rhamnosus uses the small molecular organic substances to generate lactic acid, thereby achieving lactic acidification of the food waste. The generated lactic acid enters the acetic acid fermentation chamber through the permeable membrane, and is acted upon by acetic bacteria to generate acetic acid, which is discharged through the water outlet 17. When the device is finished running, close the electric valve I 1, the electric valve III 16, the electric valve II 13 and the circulation flow pump I 14, stop feeding, turn off the agitator 10, take out the lactic acid fermentation chamber as a whole, open the top cover of the lactic acid fermentation chamber, rinse the lactic acid and acetic acid fermentation chambers with clean water, reinstall the device, open the electric valve I 1, and pass clean water to the top of the permeable membrane 7. Turn on the agitator 10, the electric valve II 13 and the circulation flow pump I 14, run stably for 1 hour, thoroughly clean the circulation pipeline 19, close the electric valve I 1, the agitator 10, the electric valve II 13 and the circulation flow pump I 14, and complete the termination of the device.

[0035] The present invention provides a water inlet for the lactic acid fermentation chamber and a water outlet for the acetic acid fermentation chamber product. When in use, a mixed liquid of kitchen waste diluted with water is introduced into the lactic acid fermentation chamber through the water inlet of the lactic acid fermentation chamber, so that the liquid level is higher than the top of the permeable membrane on the wall of the lactic acid fermentation chamber. At the same time, a pH control system is turned on to control the pH in the reactor to be 5, and a temperature control system is turned on to control the temperature in the reactor to be 36-38°C. Lactic acid generated after lactic acid fermentation of the kitchen waste enters the acetic acid fermentation chamber through the permeable membrane, thereby achieving lactic acidification of the kitchen waste. Under the promoting effect of Fe3O4 Under the above conditions, the acetic acid bacteria group uses lactic acid as a substrate to produce directional acetic acid, and the acetic acid is discharged through the water outlet provided in the acetic acid fermentation chamber, thereby realizing the production of acetic acid. Through the above, the acetic acid fermentation device of the present invention can realize the treatment of food waste, and the acetic acid fermentation of food waste using lactic acid as an intermediate and Fe3O4 as a promoter improves the fermentation purity and yield of acetic acid, realizing the directional resource utilization of food waste. The directional acetic acid fermentation device of the present invention can also realize the treatment of food industry by-products and agricultural waste and the directional acetic acid resource utilization, and has the characteristics of universal economy and environmental protection.

[0036] The lactic acid bacteria and acetic acid bacteria used in the technical solution of the present invention are abundant in source, low in price, and have strong activity. Fe3O4 is magnetic and can be recycled. In addition, the microorganisms attached to the surface of the recycled Fe3O4 are also conducive to the production of organic acids. At the same time, acetic acid is safer than methane, a product of traditional anaerobic digestion, and is non-flammable and non-explosive, thereby saving storage and transportation costs. Therefore, in summary, the product of the present invention is safer, saves costs, and reduces greenhouse gas emissions. The effects of the above-described directional acetic acid fermentation device of the present invention indicate that the directional acetic acid fermentation method of the present invention using lactic acid as an intermediate can achieve the directional conversion of food waste into acetic acid, save costs, and realize resource recycling. Therefore, it has multiple advantages such as economy, environmental protection, and resource recycling. It can solve the problem of the difficulty in directional recycling of food waste and realize the directional acetic acid resource recovery of complex organic matter.

[0037] Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A device for directional acetic acid fermentation of kitchen waste using lactic acid as an intermediate, characterized in that: The invention comprises an acetic acid fermentation chamber, wherein a lactic acid fermentation chamber is provided in the acetic acid fermentation chamber, a lactic acid fermentation chamber water inlet (2) is provided at the top of the lactic acid fermentation chamber, a permeable membrane (7) is provided on the side wall of the lactic acid fermentation chamber, and the permeable membrane (7) can allow lactic acid generated in the lactic acid fermentation chamber to enter the acetic acid fermentation chamber, and an acetic acid fermentation chamber product water outlet (17) is provided at the bottom of the acetic acid fermentation chamber. The acetic acid fermentation chamber is also connected to a circulation system for circulating liquid in the acetic acid fermentation chamber.

2. The device for directional acetic acid fermentation of kitchen waste using lactic acid as an intermediate according to claim 1, characterized in that: The lactic acid fermentation chamber is provided with a stirrer (10) for stirring the liquid in the lactic acid fermentation chamber.

3. The device for directional acetic acid fermentation of kitchen waste using lactic acid as an intermediate according to claim 1, characterized in that: The inner wall of the acetic acid fermentation chamber is provided with a temperature control layer (11) for controlling the temperature of the liquid in the acetic acid fermentation chamber.

4. The device for directional acetic acid fermentation of kitchen waste using lactic acid as an intermediate according to claim 3, characterized in that: The temperature control layer (11) adopts a cylindrical structure with a cavity interlayer and no upper bottom. The outer wall of the temperature control layer (11) is attached to the inner wall of the acetic acid fermentation chamber. The inner cavity of the temperature control layer (11) is used to hold liquid. The lactic acid fermentation chamber is located in the inner cavity of the temperature control layer (11). The temperature control layer (11) is connected to a temperature control layer water inlet (21) and a temperature control layer water outlet (6) that are in communication with the inner cavity of the cavity interlayer of the temperature control layer (11). The temperature control layer water inlet (21) is connected to a circulating flow pump II (22) and an electric valve V (23).

5. The device for directional acetic acid fermentation of kitchen waste using lactic acid as an intermediate according to claim 1, characterized in that: The circulation system includes a circulation pipeline (19), one end of which is connected to the bottom of the inner cavity of the acetic acid fermentation chamber and the other end is arranged on the top of the acetic acid fermentation chamber. The circulation pipeline (19) is sequentially provided with an electric valve II (13), a pH detector (15) and a circulation flow pump I (14).

6. The device for directional acetic acid fermentation of kitchen waste using lactic acid as an intermediate according to claim 5, characterized in that: An external pipe (20) is connected to the circulation pipe (19) between the pH detector (15) and the circulation flow pump I (14), and an electric valve IV (18) is provided on the external pipe (20).

7. The device for directional acetic acid fermentation of kitchen waste using lactic acid as an intermediate according to claim 1, characterized in that: An electric valve I (1) is provided on the water inlet (2) of the lactic acid fermentation chamber, and an electric valve III (16) is provided on the product water outlet (17) of the acetic acid fermentation chamber. The acetic acid fermentation chamber and the lactic acid fermentation chamber are both cylindrical in shape and coaxially arranged. The outer diameter of the lactic acid fermentation chamber is smaller than the inner diameter of the acetic acid fermentation chamber, and the height of the lactic acid fermentation chamber is smaller than the height of the acetic acid fermentation chamber. A temperature sensor (3) for detecting the temperature of the liquid in the acetic acid fermentation chamber is provided in the inner cavity of the acetic acid fermentation chamber.

8. A method for the directed acetic acid fermentation of food waste using lactic acid as an intermediate, characterized in that: The method is carried out using the device for directional acetic acid fermentation of kitchen waste using lactic acid as an intermediate according to any one of claims 1 to 7, and comprises: Fe3O4 powder is added to the lactic acid fermentation chamber, and a mixed liquid of food waste is introduced into the lactic acid fermentation chamber until the liquid level in the lactic acid fermentation chamber and the acetic acid fermentation chamber is higher than the top height of the permeable membrane (7); wherein the mixed liquid of food waste is obtained by diluting the food waste with water; Then, respective activated seed solutions were inoculated in the lactic acid fermentation chamber and the acetic acid fermentation chamber, wherein the activated seed solution inoculated in the lactic acid fermentation chamber was obtained by inoculating a lactic acid bacteria mass formed by immobilized Lactobacillus rhamnosus and Rhizopus into a sterilized MRS medium and culturing the same; and the activated seed solution inoculated in the acetic acid fermentation chamber was obtained by inoculating an immobilized Acetobacter mass into a sterilized GYP medium and culturing the same; After the activated seed liquid is inoculated, fermentation is carried out using a batch operation method: in the lactic acid fermentation chamber, the food waste is hydrolyzed by Rhizopus, and Lactobacillus rhamnosus uses the hydrolysis area to generate lactic acid, thereby achieving lactic acidification of the food waste; the lactic acid generated in the lactic acid fermentation chamber enters the acetic acid fermentation chamber through the permeable membrane (7), and in the acetic acid fermentation chamber, the lactic acid is generated by the action of Acetobacter to generate acetic acid, and the generated acetic acid is discharged through the acetic acid fermentation chamber product outlet (17).

9. The method for the directed acetic acid fermentation of kitchen waste using lactic acid as an intermediate according to claim 8, characterized in that: In the lactic acid fermentation room, the concentration of Fe3O4 powder is 8-12 g / L, and the particle size of Fe3O4 powder is not greater than 0.2 mm; When inoculating the respective activated seed liquids in the lactic acid fermentation chamber and the acetic acid fermentation chamber, the activated seed liquids are inoculated at an inoculation ratio of 4.5%-5.5% by volume; after inoculating the respective activated seed liquids in the lactic acid fermentation chamber and the acetic acid fermentation chamber, the pH values ​​in the lactic acid fermentation chamber and the acetic acid fermentation chamber are adjusted and controlled to be maintained at 5.0-5.5, and then the supernatants in the lactic acid fermentation chamber and the acetic acid fermentation chamber are taken at preset time intervals to detect the concentrations of the components of each fermentation liquid until the component concentrations do not change, and the inoculation start-up of the device is completed.

10. The method for directional acetic acid fermentation of kitchen waste using lactic acid as an intermediate according to claim 8, characterized in that: The total solid mass fraction in the mixed liquid of food waste is 5.5%-6.5%.

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