Overflow type two-phase anaerobic fermentation device and application method

Abstract

The invention discloses an overflow two-phase anaerobic fermentation device and an application method. The device comprises a sealed box, wherein a hydrolysis acidification tank and a methane production tank are arranged on the left and right sides of the sealed box, an overflow tank is arranged between the hydrolysis acidification tank and the methane production tank, sludge beds are arranged at the bottom of the hydrolysis acidification tank and the methane production tank, electrodes are arranged in the two sludge beds, the electrodes in the hydrolysis acidification tank are connected to the anode of an external power supply, and the electrodes in the methane production tank are connected to the cathode of the external power supply. The method comprises the following steps: S1, sludge inoculation; S2, sludge culture and domestication; S3, wastewater treatment; S4, waste detection. The present invention integrates high-concentration organic wastewater treatment, microbial culture and domestication, and fermentation performance testing, and continuously and deeply treats wastewater by overflow, which can not only achieve a dynamic balance between hydrolysis acidification and methane production processes, but also greatly improve the wastewater treatment capacity and resource utilization effect.

Description

Technical Field

[0001] The invention relates to the technical field of high-concentration organic wastewater treatment, and in particular to an overflow-type two-phase anaerobic fermentation device and an application method thereof. Background Art

[0002] With the development of industry, industrial organic wastewater pollution is becoming more and more serious. The complete anaerobic fermentation process of high-concentration organic wastewater can be divided into three stages: hydrolysis, acidification and methanogenesis. The imbalance between hydrolysis, acidification and methanogenesis will lead to serious acid accumulation and failure of anaerobic fermentation. Therefore, the two-phase fermentation method of carrying out the two processes of hydrolysis, acidification and methanogenesis in two independent devices is widely used in the treatment of high-concentration organic wastewater. It not only provides the best growth and reproduction conditions for hydrolysis and acidification bacteria and methanogens, so that they can obtain the highest reaction rate in their respective devices, but also alleviates the impact of high organic load on the methanogenesis process, effectively improving the treatment effect of organic wastewater.

[0003] At present, the two-phase anaerobic fermentation process is to simply connect the hydrolysis acidification and methanogens in series for material transfer. The independent two-phase device hinders the exchange of electrons and protons between the hydrolysis acidification bacteria and the methanogens, weakens the mutual relationship between the hydrolysis acidification bacteria and the methanogens, and makes the two-phase fermentation cycle long and the wastewater treatment is not thorough enough. At present, the resource utilization efficiency of the two-phase anaerobic fermentation is mainly improved by pumping the gas (carbon dioxide and hydrogen) produced by the hydrolysis acidification tank into the methane production tank for reuse, but there is still a problem of low mass transfer efficiency between the two phases.

[0004] Therefore, under the premise of ensuring the treatment efficiency of high-concentration organic wastewater, improving the mass transfer and efficiency of two-phase anaerobic fermentation is an urgent problem that needs to be solved. Summary of the invention

[0005] In view of the above-mentioned problems, the present invention provides an overflow two-phase anaerobic fermentation device and an application method.

[0006] The technical solution of the present invention is:

[0007] An overflow type two-phase anaerobic fermentation device comprises a sealed box, wherein a hydrolysis acidification tank and a methane production tank are arranged on the left and right sides of the sealed box, an overflow tank is arranged between the hydrolysis acidification tank and the methane production tank, a water inlet pipe is arranged at the bottom of the hydrolysis acidification tank, a three-phase separator is arranged at the upper part of the hydrolysis acidification tank and the methane production tank, a sludge bed is arranged at the bottom of the hydrolysis acidification tank and the methane production tank, electrodes are arranged in the two sludge beds, the electrodes in the hydrolysis acidification tank are connected to the anode of an external power supply, the electrodes in the methane production tank are connected to the cathode of the external power supply, and a drain pipe is arranged at the upper part of the side wall of the methane production tank.

[0008] Furthermore, the overflow trough is L-shaped, the top of the overflow trough is lower than the top edge of the hydrolysis acidification tank and the bottom of the overflow trough extends to the bottom of the methane production tank, the bottom of the hydrolysis acidification tank is provided with a first porous partition connected to the water inlet pipe, and the bottom of the methane production tank is provided with a second porous partition connected to the overflow trough.

[0009] Description: The overflow tank can be set up to connect two independent hydrolysis acidification tanks and methane production tanks by overflow, thereby improving space utilization efficiency and reducing energy loss in pumping wastewater between the two phases through a water pump.

[0010] Furthermore, the electrode is a platinum mesh electrode, and the external power supply is connected to an external resistor.

[0011] Description: The two-phase fermentation is further strengthened by adding an electrode between the two phases, and the electrons generated in the hydrolysis acidification pool are used in the methane production pool to balance the hydrolysis acidification rate and improve the efficiency of the two-phase fermentation.

[0012] Furthermore, the hydrolysis acidification tank and the methane production tank have the same shape and size, and the height of the bottom of the hydrolysis acidification tank from the top of the overflow tank is the same as the height of the bottom of the methane production tank from the drain pipe. There is a gap of 1 to 5 mm between the three-phase separator and the inner wall of the hydrolysis acidification tank and the methane production tank. The drain pipe is located above the three-phase separator, and the liquid level of the sludge bed is located at 1 / 4 to 1 / 3 in the hydrolysis acidification tank and the methane production tank.

[0013] Furthermore, exhaust pipes are provided on the tops of the two three-phase separators.

[0014] Note: The gas produced in the hydrolysis acidification tank and the methane production tank is collected in time through the three-phase separator.

[0015] The present invention also discloses an application method of an overflow two-phase anaerobic fermentation device, comprising the following steps:

[0016] S1. Sludge inoculation: anaerobic sludge is inoculated into the bottom of the hydrolysis acidification tank and the methane production tank to form a sludge bed, until the liquid level of the sludge bed is located at 1 / 4 to 1 / 3 of the hydrolysis acidification tank and the methane production tank;

[0017] S2. Sludge culture and acclimatization: inject simulated acidified wastewater containing trace elements through the water inlet pipe, turn on the external power supply, and operate at a low organic load for 7 to 15 days. The low organic load is:

[0018] The organic loading rate in simulated acidified wastewater is 0.2~1kg COD / (m 3 d), the injection rate is (n / 1000~n / 200)mL / min, where n is the volume of the hydrolysis acidification tank and the methane production tank;

[0019] Then the organic loading rate in the simulated acidified wastewater was increased to 1-4 kg COD / (m 3 ·d), increase the injection rate to (n / 800~n / 200)mL / min, control the internal temperature of the sealed box to 35~37℃, the water retention time in the sealed box to 8~24h, and maintain for 3~5d;

[0020] S3, wastewater treatment: the wastewater to be treated is injected into the hydrolysis acidification tank through the water inlet pipe, the injection speed is (n / 800~n / 200)mL / min, the external power supply is turned on, the hydrolysis acidification reaction is carried out, the temperature inside the sealed box is controlled to be 35~37℃, the wastewater is decomposed into volatile fatty acids, and part of the electrons generated are transferred to the methane production tank through the potential difference, and then the wastewater enters the methane production tank through the overflow tank, and the anaerobic sludge uses the electrons transferred by the hydrolysis acidification tank through the external circuit and the protons coupled with the electron transfer and the high-quality carbon source generated by the hydrolysis acidification tank to synthesize methane, keep the pH of the hydrolysis acidification tank stable at 5.8~6.5, and the pH of the methane production tank stable at 6.8~7.2, the hydraulic retention time in the sealed box is 8~24h, and finally the wastewater is discharged through the drain pipe, and the generated gas is collected by two three-phase separators;

[0021] S4. Waste detection: Detect and maintain the voltage across the external resistor stable, and detect the gas components and wastewater COD produced by the hydrolysis acidification tank and methane production tank.

[0022] Furthermore, the anaerobic sludge is flocculent, the volatile suspended matter (VSS) content of the anaerobic sludge is 3-5%, and the anaerobic sludge is washed 3-5 times with physiological saline having a mass concentration of 0.9% before inoculation.

[0023] Description: Anaerobic sludge is cleaned with saline to remove impurities in the anaerobic sludge, including suspended matter and dissolved organic matter.

[0024] Furthermore, the simulated acidified wastewater containing trace elements contains CH 12 The content of O6 is 1800-1900 mg / L, the content of NH4Cl is 180-190 mg / L, the content of KH2PO4 is 70-80 mg / L, the content of MnCl2·4H2O is 2 mg / L, the content of CaCl2 is 2 mg / L, the content of FeCl3 is 1 mg / L, the content of ZnCl2·4H2O is 1 mg / L, and the content of MgCl2·6H2O is 1 mg / L.

[0025] Description: Anaerobic sludge is cultivated and domesticated by simulating easily acidified wastewater, so that it can subsequently treat wastewater efficiently.

[0026] Furthermore, in step S3, the voltage of the external power supply is 0.4-1.5V, and the external resistance of the external power supply is 0.1-2MΩ.

[0027] The beneficial effects of the present invention are:

[0028] The overflow two-phase anaerobic fermentation device and application method of the present invention integrate high-concentration organic wastewater treatment, microbial cultivation and domestication, and fermentation performance testing. The wastewater is continuously and deeply treated by overflow. The wastewater first enters a hydrolysis and acidification tank, then enters a methane production tank through an overflow tank, and is finally discharged from the methane production tank. The energy loss of pumping water between the two tanks is eliminated, and the mass transfer and efficiency transfer between the hydrolysis and acidification tank and the methane production tank are strengthened. Not only can the dynamic balance of the hydrolysis and acidification and methanogenesis processes be achieved, but also the wastewater treatment capacity and resource utilization effect are greatly improved. By detecting the voltage across an external resistor, the electron transfer activity between the fermentation bacteria can be intuitively observed, which plays an important role in screening electron-interactive bacteria. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the overall structure of an overflow two-phase anaerobic fermentation device of the present invention;

[0030] Figure 2 It is a COD degradation rate diagram in the experimental example of the present invention;

[0031] Figure 3 is a graph of methane production in an experimental example of the present invention;

[0032] Figure 4 is a graph of hydrogen production in an experimental example of the present invention;

[0033] Figure 5 is the current diagram of the MCTF group in the experimental example of the present invention;

[0034] Figure 6 This is the electron transfer activity diagram of the methane production pool in the experimental example of the present invention.

[0035] Among them, 1-sealed box, 2-hydrolysis acidification tank, 21-water inlet pipe, 3-methane production tank, 31-drain pipe, 32-second porous partition, 4-overflow tank, 5-three-phase separator, 51-exhaust pipe, 6-sludge bed, 7-electrode, 8-external power supply, 81-external resistor. DETAILED DESCRIPTION

[0036] Example 1

[0037] An overflow type two-phase anaerobic fermentation device comprises a sealed box body 1, wherein a hydrolysis acidification tank 2 and a methane production tank 3 are arranged on the left and right sides of the sealed box body 1, an overflow tank 4 is arranged between the hydrolysis acidification tank 2 and the methane production tank 3, the overflow tank 4 is L-shaped, the top of the overflow tank 4 is lower than the top edge of the hydrolysis acidification tank 2 and the bottom of the overflow tank 4 extends to the bottom of the methane production tank 3, the bottom of the hydrolysis acidification tank 2 is provided with a first porous partition 22 connected to the water inlet pipe 21, the bottom of the methane production tank 3 is provided with a second porous partition 32 connected to the overflow tank 4, the hydrolysis acidification tank 2 is provided with a first porous partition 22 connected to the water inlet pipe 21, the bottom of the methane production tank 3 is provided with a second porous partition 32 connected to the overflow tank 4, A water inlet pipe 21 is provided at the bottom of the pool 2, a three-phase separator 5 is provided at the upper part of the hydrolysis acidification pool 2 and the methane production pool 3, and an exhaust pipe 51 is provided at the top of the two three-phase separators 5. A sludge bed 6 is provided at the bottom of the hydrolysis acidification pool 2 and the methane production pool 3, and electrodes 7 are provided in the two sludge beds 6. The electrode 7 in the hydrolysis acidification pool 2 is connected to the anode of the external power supply 8, and the electrode 7 in the methane production pool 3 is connected to the cathode of the external power supply 8. The electrode 7 is a platinum mesh electrode, and the external power supply 8 is connected to an external resistor 81. A drain pipe 31 is provided at the upper part of the side wall of the methane production pool 3;

[0038] The hydrolysis acidification tank 2 and the methane production tank 3 have the same shape and size, and the height of the bottom of the hydrolysis acidification tank 2 from the top of the overflow tank 4 is the same as the height of the bottom of the methane production tank 3 from the drain pipe 31. There is a 2 mm gap between the three-phase separator 5 and the inner wall of the hydrolysis acidification tank 2 and the methane production tank 3. The drain pipe 31 is located above the three-phase separator 5. The liquid level of the sludge bed 6 is located at 1 / 4 of the hydrolysis acidification tank 2 and the methane production tank 3.

[0039] Example 2

[0040] The difference between this embodiment and embodiment 1 is that:

[0041] The liquid level of the sludge bed 6 is located at 1 / 3 of the hydrolysis acidification tank 2 and the methane production tank 3 , and there is a 4 mm gap between the three-phase separator 5 and the inner wall of the hydrolysis acidification tank 2 and the methane production tank 3 .

[0042] Example 3

[0043] This embodiment is an application method of an overflow two-phase anaerobic fermentation device in Embodiment 1, comprising the following steps:

[0044] S1. Sludge inoculation: anaerobic sludge is inoculated into the bottom of the hydrolysis acidification tank 2 and the methane production tank 3 to form a sludge bed 6, until the liquid level of the sludge bed 6 is located at 1 / 4 of the hydrolysis acidification tank 2 and the methane production tank 3. The anaerobic sludge is flocculent, and the volatile suspended matter VSS content of the anaerobic sludge is 4%. The anaerobic sludge is washed 4 times with physiological saline with a mass concentration of 0.9% before inoculation;

[0045] S2. Sludge cultivation and acclimatization: simulated acidified wastewater containing trace elements is injected through the water inlet pipe 21. The C6H12 The content of O6 is 1875mg / L, the content of NH4Cl is 187.5mg / L, the content of KH2PO4 is 75mg / L, the content of MnCl2·4H2O is 2mg / L, the content of CaCl2 is 2mg / L, the content of FeCl3 is 1mg / L, the content of ZnCl2·4H2O is 1mg / L, the content of MgCl2·6H2O is 1mg / L, the external power supply 8 is turned on, and the system is operated at low organic load for 10d. The low organic load is:

[0046] The organic loading rate in the simulated acidified wastewater is 0.5 kg COD / (m 3 d), the injection rate is (n / 900) mL / min, where n is the volume of the hydrolysis acidification pool 2 and the methane production pool 3;

[0047] Then the organic loading rate in the simulated acidified wastewater was increased to 2 kg COD / (m 3 d), increase the injection rate to (n / 700) mL / min, control the internal temperature of the sealed box 1 to 36°C, and the water retention time in the sealed box 1 to 12 hours, and maintain for 4 days;

[0048] S3, wastewater treatment: the wastewater to be treated is injected into the hydrolysis acidification tank 2 through the water inlet pipe 21, the injection speed is (n / 700) mL / min, the external power supply 8 is turned on, the hydrolysis acidification reaction is carried out, the temperature inside the sealed box 1 is controlled to be 36°C, the wastewater is decomposed into volatile fatty acids, and part of the electrons generated are transferred to the methane production tank 3 through the potential difference, and then the wastewater enters the methane production tank 3 through the overflow tank 4, and the anaerobic sludge uses the electrons transferred by the hydrolysis acidification tank 2 through the external circuit and the protons coupled with the electron transfer and the high-quality carbon source generated by the hydrolysis acidification tank 2 to synthesize methane, keep the pH of the hydrolysis acidification tank 2 stable at 6.2, and the pH of the methane production tank 3 stable at 7, the hydraulic retention time in the sealed box 1 is 16h, and finally the wastewater is discharged through the drain pipe 31, and the two three-phase separators 5 collect the generated gas;

[0049] S4. Waste detection: detect and maintain the voltage across the external resistor 81 stable, the voltage of the external power supply 8 is 1.2V, the external resistor 81 of the external power supply 8 is 1MΩ, and at the same time detect the gas components and wastewater COD generated by the hydrolysis acidification tank 2 and the methane production tank 3.

[0050] Example 4

[0051] The difference between this embodiment and embodiment 3 is that:

[0052] C6H in simulated acidified wastewater containing trace elements 12The content of O6 is 1875mg / L, the content of NH4Cl is 187.5mg / L, the content of KH2PO4 is 70mg / L, the content of MnCl2·4H2O is 2mg / L, the content of CaCl2 is 2mg / L, the content of FeCl3 is 1mg / L, the content of ZnCl2·4H2O is 1mg / L, and the content of MgCl2·6H2O is 1mg / L.

[0053] Example 5

[0054] The difference between this embodiment and embodiment 3 is that:

[0055] C6H in simulated acidified wastewater containing trace elements 12 The content of O6 is 1875mg / L, the content of NH4Cl is 187.5mg / L, the content of KH2PO4 is 80mg / L, the content of MnCl2·4H2O is 2mg / L, the content of CaCl2 is 2mg / L, the content of FeCl3 is 1mg / L, the content of ZnCl2·4H2O is 1mg / L, and the content of MgCl2·6H2O is 1mg / L.

[0056] Example 6

[0057] The difference between this embodiment and embodiment 3 is that:

[0058] C6H in simulated acidified wastewater containing trace elements 12 The content of O6 is 1820mg / L, the content of NH4Cl is 182mg / L, the content of KH2PO4 is 72mg / L, the content of MnCl2·4H2O is 2mg / L, the content of CaCl2 is 2mg / L, the content of FeCl3 is 1mg / L, the content of ZnCl2·4H2O is 1mg / L, and the content of MgCl2·6H2O is 1mg / L.

[0059] Example 7

[0060] The difference between this embodiment and embodiment 3 is that:

[0061] S2. Sludge culture and acclimatization: operate at low organic load for 7 days, the low organic load is:

[0062] The organic loading rate in the simulated acidified wastewater is 1kg COD / (m 3 d), the injection rate is (n / 200) mL / min, where n is the volume of the hydrolysis acidification pool 2 and the methane production pool 3;

[0063] Then the organic loading rate in the simulated acidified wastewater was increased to 4 kg COD / (m 3·d), increase the injection rate to (n / 200) mL / min, control the internal temperature of the sealed box 1 to 35°C, and the hydraulic retention time in the sealed box 1 to 8 hours, which is maintained for 3 days.

[0064] Example 8

[0065] The difference between this embodiment and embodiment 3 is that:

[0066] S2. Sludge culture and acclimatization: operate at low organic load for 15 days, the low organic load is:

[0067] The organic loading rate in the simulated acidified wastewater is 0.2 kg COD / (m 3 d), the injection rate is (n / 1000) mL / min, where n is the volume of the hydrolysis acidification pool 2 and the methane production pool 3;

[0068] Then the organic loading rate in the simulated acidified wastewater was increased to 1 kg COD / (m 3 ·d), increase the injection rate to (n / 800) mL / min, control the internal temperature of the sealed box 1 to 37°C, and the water retention time in the sealed box 1 to 24h, which is maintained for 5 days.

[0069] Note: When the low organic load operation time is shorter, the controlled organic load rate increases, the injection speed increases, and the hydraulic retention time decreases accordingly; and when the low organic load operation time is longer, the controlled organic load rate decreases, the injection speed decreases, and the hydraulic retention time increases accordingly.

[0070] Example 9

[0071] The difference between this embodiment and embodiment 3 is that the basic parameters are different.

[0072] S1. Sludge inoculation: The volatile suspended solids (VSS) content of the anaerobic sludge is 3%. The anaerobic sludge is washed three times with 0.9% saline before inoculation.

[0073] S3, wastewater treatment: the wastewater to be treated is injected into the hydrolysis acidification tank 2 through the water inlet pipe 21, the injection speed is (n / 300) mL / min, the external power supply 8 is turned on, the hydrolysis acidification reaction is carried out, the internal temperature of the sealed box 1 is controlled to be 35°C, the wastewater is decomposed into volatile fatty acids, and part of the electrons generated are transferred to the methane production tank 3 through the potential difference, and then the wastewater enters the methane production tank 3 through the overflow tank 4, and the anaerobic sludge uses the electrons transferred by the hydrolysis acidification tank 2 through the external circuit and the protons coupled with the electron transfer and the high-quality carbon source generated by the hydrolysis acidification tank 2 to synthesize methane, keep the pH of the hydrolysis acidification tank 2 stable at 5.8, and the pH of the methane production tank 3 stable at 6.8, the hydraulic retention time in the sealed box 1 is 24h, and finally the wastewater is discharged through the drain pipe 31, and the two three-phase separators 5 collect the generated gas;

[0074] S4. Waste detection: detect and maintain the voltage across the external resistor 81 stable, the voltage of the external power supply 8 is 0.4V, the external resistor 81 of the external power supply 8 is 0.1MΩ, and at the same time detect the gas components and wastewater COD produced by the hydrolysis acidification tank 2 and the methane production tank 3.

[0075] Example 10

[0076] The difference between this embodiment and embodiment 3 is that the basic parameters are different.

[0077] S1. Sludge inoculation: The volatile suspended solids (VSS) content of the anaerobic sludge is 5%. The anaerobic sludge is washed five times with 0.9% saline before inoculation.

[0078] S3, wastewater treatment: the wastewater to be treated is injected into the hydrolysis acidification tank 2 through the water inlet pipe 21, the injection speed is (n / 600) mL / min, the external power supply 8 is turned on, the hydrolysis acidification reaction is carried out, the internal temperature of the sealed box 1 is controlled to be 37°C, the wastewater is decomposed into volatile fatty acids, and part of the electrons generated are transferred to the methane production tank 3 through the potential difference, and then the wastewater enters the methane production tank 3 through the overflow tank 4, and the anaerobic sludge uses the electrons transferred by the hydrolysis acidification tank 2 through the external circuit and the protons coupled with the electron transfer and the high-quality carbon source generated by the hydrolysis acidification tank 2 to synthesize methane, keep the pH of the hydrolysis acidification tank 2 stable at 6.5, and the pH of the methane production tank 3 stable at 7.2, the hydraulic retention time in the sealed box 1 is 8h, and finally the wastewater is discharged through the drain pipe 31, and the two three-phase separators collect the generated gas;

[0079] S4. Waste detection: detect and maintain the voltage across the external resistor 81 stable, the voltage of the external power supply 8 is 1.5V, the external resistor 81 of the external power supply 8 is 2MΩ, and at the same time detect the gas components and wastewater COD generated by the hydrolysis acidification tank 2 and the methane production tank 3.

[0080] Experimental example

[0081] The overflow two-phase anaerobic fermentation device of the present invention is simulated and tested below. The method parameters in Example 3 are taken as an example (referred to as MCTF group), wherein the length, width and height of the hydrolysis acidification tank 2 and the methane production tank 3 are 6*6*10 cm, the upper part of the overflow tank 4 is 8 cm high, the lower part is 1 cm, and the width is 1 cm. The size of the electrode 7 is 3.5 cm×3.5 cm, the electrode rod height of the hydrolysis acidification tank 2 is 6 cm, and the electrode rod height of the methane production tank 3 is 5 cm. The pore size of the first porous partition 22 and the second porous partition 32 is 0.1-0.2 mm. In step S3, 1000 mg COD / L simulated acidified wastewater is injected into the water inlet of the device at a flow rate of 0.3-2 mL / min through a peristaltic pump, and the device is maintained at 37° C. through a water bath and operated for 30 days. During this process, the water inlet flow rate is gradually increased according to the effluent COD and gas production to ensure stable operation.

[0082] At the same time, a control experiment was carried out. In the hydrolysis acidification tank 2 and the methane production tank 3 of the overflow two-phase anaerobic fermentation device of the present invention, no electrode 7 was added as comparative example 1 (referred to as Control group), and in the hydrolysis acidification tank 2 and the methane production tank 3, only the electrode 7 was added without inoculating flocculent sludge as comparative example 2 (referred to as Control-2 group). Other operations were the same as those in Example 3.

[0083] Gas component test method: The gases to be measured in this system include methane, hydrogen and carbon dioxide. The data in this method are detected using a gas chromatograph (Agilent 6890N, USA).

[0084] Wastewater degradation test method,This system needs to determine the COD degradation rate of wastewater after treatment in the hydrolysis acidification tank and the methane production tank. First, it is filtered through a 0.45nm polyethersulfone filter head and then the COD test is performed using a COD digestion reagent (Hash Technology, China) and a COD digestion detector.

[0085] Electron transfer activity test method: In this system, sludge from hydrolysis acidification tanks and methane production tanks at different fermentation periods was used to test the microbial electron transfer activity using the INT-ETS method.

[0086] The test results show that under low organic loading rate conditions (OLR < 0.5 kgCOD / (m 3 ·d)), the effluent COD and methane production of the Control group and the MCTF group were similar. With the increase of organic loading rate (OLR>0.5kgCOD / (m 3 ·d)), there were significant differences between the Control group and the MCTF group, e.g. Figure 2 and Figure 3 As shown, when the organic loading rate is 3kgCOD / (m 3·d), the COD removal rate of the MCTF group stabilized at more than 95%, while the Control group finally stabilized at 52%; the Control-2 group had no effect on sewage degradation;

[0087] As shown in Table 1, compared with the low organic loading rate (OLR>0.5kgCOD / (m 3 Compared with the MCTF group, the MCTF group increased the wastewater treatment efficiency by more than two times. The MCTF group had a high organic load (OLR = 3 kgCOD / (m 3 d) Methane production reached 180 mL, an increase of 76% compared to 102 mL in the Control group;

[0088] Table 1 Comparison of COD removal rates of different reaction devices

[0089]

[0090] like Figure 4 As shown, the hydrogen production of the Control group increased with the increase of organic loading rate, and the maximum value reached 98mL, while the maximum value of hydrogen production of the MCTF group was only 8.1mL, indicating that the protons produced by the hydrolysis acidification pool 2 entered the methane production pool 3 through coupled electron transfer to participate in methane synthesis, thereby significantly increasing the methane production of the MCTF group;

[0091] like Figure 5 As shown in the figure, the current curve of the MCTF group showed an S-shape and stabilized at 108·10 -3 In summary, the device builds a stable electron transfer network and promotes proton-coupled electron transfer between the hydrolysis acidification tank and the methane production tank, thereby significantly improving the treatment efficiency and resource utilization effect of organic wastewater;

[0092] like Figure 6 As shown, the electron transfer activity of the Control group and the MCTF group was detected at different times. The electron transfer activity of the MCTF group was 7 times that of the Control group. The increase in the electron transfer activity of the MCTF group was positively correlated with the increase in current. Therefore, the electron transfer activity of the methane production pool can be reflected by the current curve.

Claims

1. An overflow two-phase anaerobic fermentation device, characterized in that: The invention comprises a sealed box (1), wherein a hydrolysis acidification tank (2) and a methane production tank (3) are arranged on the left and right sides of the sealed box (1), an overflow tank (4) is arranged between the hydrolysis acidification tank (2) and the methane production tank (3), a water inlet pipe (21) is arranged at the bottom of the hydrolysis acidification tank (2), a three-phase separator (5) is arranged at the upper part of the hydrolysis acidification tank (2) and the methane production tank (3), a sludge bed (6) is arranged at the bottom of the hydrolysis acidification tank (2) and the methane production tank (3), electrodes (7) are arranged in the two sludge beds (6), the electrodes (7) in the hydrolysis acidification tank (2) are connected to the anode of an external power supply (8), the electrodes (7) in the methane production tank (3) are connected to the cathode of the external power supply (8), and a drainage pipe (31) is arranged at the upper part of the side wall of the methane production tank (3); The overflow trough (4) is L-shaped, the top of the overflow trough (4) is lower than the top edge of the hydrolysis acidification tank (2) and the bottom of the overflow trough (4) extends to the bottom of the methane production tank (3), and the external power supply (8) is connected to an external resistor (81).

2. The overflow two-phase anaerobic fermentation device according to claim 1, characterized in that: A first porous baffle (22) connected to the water inlet pipe (21) is provided at the bottom of the hydrolysis acidification tank (2), and a second porous baffle (32) connected to the overflow tank (4) is provided at the bottom of the methane production tank (3).

3. The overflow two-phase anaerobic fermentation device according to claim 1, characterized in that: The electrode (7) is a platinum mesh electrode.

4. The overflow two-phase anaerobic fermentation device according to claim 1, characterized in that: The hydrolysis acidification tank (2) and the methane production tank (3) have the same shape and size, and the height of the bottom of the hydrolysis acidification tank (2) from the top of the overflow tank (4) is the same as the height of the bottom of the methane production tank (3) from the drain pipe (31). There is a gap of 1 to 5 mm between the three-phase separator (5) and the inner wall of the hydrolysis acidification tank (2) and the methane production tank (3). The drain pipe (31) is located above the three-phase separator (5). The liquid level of the sludge bed (6) is located at 1 / 4 to 1 / 3 of the hydrolysis acidification tank (2) and the methane production tank (3).

5. The overflow two-phase anaerobic fermentation device according to claim 1, characterized in that: An exhaust pipe (51) is provided at the top of each of the two three-phase separators (5).

6. The application method of the overflow two-phase anaerobic fermentation device according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Sludge inoculation: anaerobic sludge is inoculated into the bottom of the hydrolysis acidification tank (2) and the methane production tank (3) to form a sludge bed (6), until the liquid level of the sludge bed (6) is located at 1 / 4 to 1 / 3 of the hydrolysis acidification tank (2) and the methane production tank (3); S2. Sludge culture and acclimatization: simulated acidified wastewater containing trace elements is injected through the water inlet pipe (21), and the external power supply (8) is turned on to operate at a low organic load for 7 to 15 days. The low organic load is: The organic loading rate in simulated acidified wastewater is 0.2~1kg COD / (m 3 d), the injection rate is (n / 1000~n / 200)mL / min, where n is the volume of the hydrolysis acidification pool (2) and the methane production pool (3); Then the organic loading rate in the simulated acidified wastewater was increased to 1-4 kg COD / (m 3 d), increase the injection rate to (n / 800~n / 200)mL / min, control the internal temperature of the sealed box (1) to 35~37°C, and the water retention time in the sealed box (1) to 8~24h, which is maintained for 3~5d; S3. Wastewater treatment: The wastewater to be treated is injected into the hydrolysis acidification tank (2) through the water inlet pipe (21) at an injection rate of (n / 800~n / 200) mL / min. The external power supply (8) is turned on to carry out the hydrolysis acidification reaction. The internal temperature of the sealed box (1) is controlled to be 35~37°C. The wastewater is decomposed into volatile fatty acids. At the same time, part of the electrons generated are transferred to the methane production pool (3) through the potential difference. Then the wastewater passes through the overflow tank (4) and enters the methane production pool (3). Pool (3), anaerobic sludge utilizes the electrons transferred by the hydrolysis acidification pool (2) through the external circuit and the protons coupled with the electron transfer and the high-quality carbon source produced by the hydrolysis acidification pool (2) to synthesize methane, the pH of the hydrolysis acidification pool (2) is kept stable at 5.8-6.5, the pH of the methane production pool (3) is kept stable at 6.8-7.2, the hydraulic retention time in the sealed box (1) is 8-24 hours, and finally the wastewater is discharged through the drain pipe (31), and the generated gas is collected by two three-phase separators (5); S4. Waste detection: Detect and maintain the voltage across the external resistor (81) stable, and simultaneously detect the gas components and wastewater COD generated by the hydrolysis acidification pool (2) and the methane production pool (3).

7. The application method of the overflow two-phase anaerobic fermentation device according to claim 6, characterized in that: The anaerobic sludge is flocculent, and the volatile suspended matter (VSS) content of the anaerobic sludge is 3-5%. Before inoculation, the anaerobic sludge is washed 3-5 times with physiological saline with a mass concentration of 0.9%.

8. The application method of the overflow two-phase anaerobic fermentation device according to claim 6, characterized in that: The CH2H2O2 in the simulated acidified wastewater containing trace elements 12 The content of O6 is 1800~1900mg / L, the content of NH4Cl is 180~190mg / L, the content of KH2PO4 is 70~80mg / L, the content of MnCl2·4H2O is 2mg / L, the content of CaCl2 is 2mg / L, the content of FeCl3 is 1mg / L, the content of ZnCl2·4H2O is 1mg / L, and the content of MgCl2∙6H2O is 1mg / L.

9. The application method of the overflow two-phase anaerobic fermentation device according to claim 6, characterized in that: In step S3, the voltage of the external power supply (8) is 0.4-1.5V, and the external resistor (81) of the external power supply (8) is 0.1-2MΩ.

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