Application method of phase separation enhanced electron transfer in longitudinal phase separation anaerobic reactor

Abstract

This invention discloses a method for enhancing electron transfer in a longitudinal phase-separation anaerobic reactor. This method achieves efficient degradation of various recalcitrant organic wastewaters and efficient biogas recovery in the anaerobic reactor. By longitudinally partitioning the reactor, relative phase separation of the acid-producing and methanogenic stages is achieved. Precise addition of acid-producing and methanogenic phase media materials through phase separation enhances the electron transfer process in the anaerobic treatment, resulting in a faster electron transfer rate, improved stability and pollutant treatment efficiency, shorter reactor start-up time, smaller footprint, easier control, lower cumulative effects of intermediate products such as VFAs, and higher treatment efficiency and energy recovery rate.

Description

Technical Field

[0001] This invention belongs to the field of anaerobic reactor technology, and specifically relates to a method for using a longitudinal phase separation anaerobic reactor. Background Technology

[0002] Anaerobic wastewater treatment technology is widely used in wastewater treatment due to its economic and environmentally friendly characteristics. It can also generate methane, allowing for energy recovery and utilization, which is of great significance in alleviating global energy shortages. To achieve high efficiency in anaerobic wastewater treatment, various classic anaerobic reactors, such as UASB reactors, EGSB reactors, and IC reactors, have been developed. However, for high-concentration, recalcitrant toxic wastewater, conventional anaerobic reactors exhibit poor treatment efficiency and low methane yield. In recent years, to further improve the treatment efficiency and applicability of anaerobic reactors, novel improved anaerobic reactors, such as the controllable dual-cycle anaerobic reactor, have been developed.

[0003] The controllable dual-circulation anaerobic reactor (publication number: CN105753147A) is an improvement on the internal circulation (IC) reactor. By adding an external controllable circulation device, it solves the problem of low biogas production preventing the initiation of internal circulation in the initial stage of the IC reactor, thus improving the reactor's start-up efficiency and applicability to recalcitrant wastewater. However, under anaerobic conditions, the reactor's biodegradation efficiency is low due to the biotoxicity of pollutants and their degradation intermediates, as well as limitations in electron transport rates. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a longitudinal phase separation anaerobic reactor.

[0005] Another objective of this invention is to provide a method for using the aforementioned longitudinal phase separation anaerobic reactor, which achieves efficient degradation of various recalcitrant organic wastewaters and efficient biogas recovery within the anaerobic reactor. By longitudinally partitioning the reactor, relative phase separation of the acid-producing and methanogenic stages is achieved. Precise addition of acid-producing and methanogenic phase media materials through phase separation enhances the electron transfer process in the anaerobic treatment, resulting in a faster electron transfer rate, improved stability and pollutant treatment efficiency, shorter reactor start-up time, smaller footprint, easier control, lower cumulative effects of intermediate products such as VFAs, and higher treatment efficiency and energy recovery rate.

[0006] The objective of this invention is achieved through the following technical solution.

[0007] A longitudinal phase separation anaerobic reactor includes: a reactor body, an inlet pipe, a first collection hood, a second collection hood, and a degassing tank. The reactor body is a sealed tank. The first collection hood is located below the second collection hood. Both the first and second collection hoods are installed inside the reactor body. A first sludge discharge port and an inlet are provided on the reactor body below the first collection hood. The inlet pipe is located outside the reactor body, and one end of the inlet pipe is connected to the inlet for feeding wastewater to be degraded into the reactor body. A second sludge discharge port is provided on the reactor body above the first collection hood.

[0008] The degassing tank is located above the reactor body. An exhaust port is formed on the degassing tank. A baffle is installed inside the degassing tank to divide it into a first space and a second space. A first riser pipe, a second riser pipe, a first return pipe, and a second return pipe are connected to the degassing tank. One end of the first return pipe and one end of the first riser pipe are respectively connected to the first space. One end of the second return pipe and one end of the second riser pipe are respectively connected to the second space. The other end of the first return pipe extends into the reactor body and is close to the bottom of the reactor body. A return inlet is formed on the reactor body between the first and second collection hoods. The other end of the second return pipe is connected to the return inlet. The reactor body is configured such that the other end of the first riser pipe is connected to the upper part of the first collection hood and a first pump is installed on the first riser pipe; the other end of the second riser pipe is connected to the upper part of the second collection hood and a second pump is installed on the second riser pipe; both the first and second collection hoods are tapered from bottom to top, used to sequentially guide the wastewater collected from the first and second collection hoods into the first and second riser pipes; a first gap is formed between the edge of the first collection hood and the inner wall of the reactor body, and a 30-40 mesh separator is installed on the first gap; a second gap is formed between the edge of the second collection hood and the inner wall of the reactor body; and an outlet pipe is connected to the reactor body above the second collection hood.

[0009] A first material inlet is formed on the reactor body below the first collection hood, and a second material inlet is formed on the reactor body between the first collection hood and the second collection hood.

[0010] The above technical solution also includes: a water distributor that is connected to the water inlet pipe and located inside the reactor body.

[0011] In the above technical solution, the first space and the second space are respectively connected to the exhaust port.

[0012] In the above technical solution, the lower part of the first space and the lower part of the second space are separated by the baffle, and the upper part of the first space and the upper part of the second space are connected.

[0013] In the above technical solution, the reflux inlet is located near the first collection hood.

[0014] In the above technical solution, the position where the first riser pipe is connected to the first space is higher than the position where the first return pipe is connected to the first space, and the position where the second riser pipe is connected to the second space is higher than the position where the second return pipe is connected to the second space.

[0015] In the above technical solution, the water outlet pipe is bent to form a water trap, which is used to form a water seal on the water outlet pipe.

[0016] In the above technical solution, a water outlet weir is installed on the inner wall of the reactor body, and the water outlet weir is connected to the water outlet pipe.

[0017] In the above technical solution, a first valve is installed on the first material inlet and a second valve is installed on the second material inlet.

[0018] In the above technical solution, a heat insulation layer is installed around the reactor body.

[0019] In the above technical solution, the first return pipe passes through the first collection hood and the second collection hood.

[0020] The method of using the above-mentioned longitudinal phase separation anaerobic reactor includes the following steps:

[0021] Step 1: Add anaerobic granular sludge to the first and second sludge discharge ports so that the volume of anaerobic granular sludge filled between the first and second collection hoods accounts for 25-35% of the volume of the methane phase, and the volume of anaerobic granular sludge filled below the first collection hood accounts for 25-35% of the volume of the acid-producing phase.

[0022] Step 2: Add culture medium into the reactor body through the inlet pipe until the reactor body is full, adjust the pH of the acid-producing phase to 5.5-6, and adjust the pH of the methanogenic phase to 7.5-7.8;

[0023] In step 2, a culture medium is prepared according to the concentration of volatile suspended solids (VSS) a mg / L in the anaerobic granular sludge. The culture medium includes a main component and a secondary component, and the ratio of the main component to the secondary component by volume is 1000:1. The main components are shown in Table 1, and the secondary components are shown in Table 2.

[0024] Table 1

[0025] principal component Concentration (mg / L) glucose 2000a ammonium chloride 600a Anhydrous calcium chloride 20a Potassium dihydrogen phosphate 40a Sodium bicarbonate 3000 Magnesium chloride hexahydrate 60a water -

[0026] Table 2

[0027]

[0028]

[0029] Step 3: Test the effluent quality of the acid-producing phase until the volatile acid concentration reaches 1500 mg / L, at which point the sludge culture in the acid-producing phase ends; and until the specific methanogenic activity of the sludge in the methanogenic phase reaches 50 mL CH4 / (gVSS·d) or higher, at which point the sludge culture in the methanogenic phase ends.

[0030] Step 4: Add acid-producing phase mediating material to the acid-producing phase and add methanogenic phase mediating material to the methanogenic phase;

[0031] In step 4, the mass of the acid-producing phase medium material added per liter of acid-producing phase is 1-2g, and the mass of the methanogenic phase medium material added per liter of methanogenic phase is 1-2g.

[0032] Step 5, Formal Treatment: Wastewater is introduced into reactor body 1 through inlet pipe 14.

[0033] In step 4, the preparation method of the acid-producing phase medium material is as follows: bamboo powder, KHCO3 as an activator and thiourea are uniformly mixed in deionized water at a mass ratio of 1:2:(0.8-1.2), stirred and reacted, dried, and then kept at 480-520℃ for 1.5-2.5h in a nitrogen or inert gas environment, and naturally cooled to room temperature to obtain the acid-producing phase medium material.

[0034] In step 4, the preparation method of the methanogenic phase medium material is as follows: In deionized water, bamboo powder, KHCO3 as an activator, and nitrogen source are uniformly mixed at a mass ratio of 2:2:(0.8-1.2), stirred and reacted, dried, and then pyrolyzed: Under nitrogen or inert gas environment, the mixture is kept at 580-620℃ for 1.5-2.5h, and then naturally cooled to room temperature to obtain an intermediate product. The intermediate product is acid-washed, filtered, washed with deionized water until the filtrate is neutral, dried, and then the intermediate product and K2FeO4 are uniformly mixed in deionized water at a mass ratio of 1:(0.3-0.5), stirred and reacted, dried, and then calcined at high temperature: Under nitrogen or inert gas environment, the mixture is kept at 580-620℃ for 1.5-2.5h, and then naturally cooled to room temperature to obtain the methanogenic phase medium material.

[0035] In the above technical solution, the pickling is performed using a 0.5-1 mol / L hydrochloric acid aqueous solution.

[0036] In the above technical solution, the nitrogen source is urea.

[0037] In the above technical solution, the particle size of the bamboo powder is 10-40 mesh.

[0038] In the above technical solution, the stirring reaction is carried out by stirring in a water bath at 80-100°C for 4-10 hours.

[0039] The beneficial effects of this invention are as follows:

[0040] 1. Adding acid-producing phase media materials and methanogenic phase media materials can enhance electron transfer efficiency, improve the shock resistance and stability of the longitudinal phase separation anaerobic reactor, ensure effluent quality, enable the longitudinal phase separation anaerobic reactor to start up quickly, maintain a stable and efficient operating state, and have a good treatment effect on recalcitrant toxic wastewater (such as azo dye wastewater), achieving high-efficiency wastewater degradation, ensuring stable effluent quality, and obtaining a high methane yield.

[0041] 2. Adding acid-producing phase media material to the acid-producing phase of the longitudinal phase separation anaerobic reactor can enhance electron transfer between microorganisms and pollutants in the acid-producing phase, enabling rapid detoxification of toxic substances.

[0042] 3. Adding methanogenic phase media materials to the methanogenic phase of a longitudinal phase separation anaerobic reactor can enhance the interspecies electron transfer efficiency (DIET) of microorganisms in the methanogenic phase and accelerate the methanogenic process.

[0043] 4. The method of using this invention allows acid-producing bacteria and methanogenic bacteria to grow under optimal conditions, resulting in a microbial community with higher activity and abundance, thereby accelerating the degradation rate of pollutants and alleviating the accumulation of intermediate products such as volatile fatty acids. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the longitudinal phase separation anaerobic reactor of the present invention;

[0045] Figure 2 The COD removal rate of the method used in Example 3 and Comparative Examples 1-3 is shown in the figure (Example 3 is shown in the figure).

[0046] Figure 3 The decolorization rate of the method used in Example 3 and Comparative Examples 1-3 is shown in the figure (Example 3 is shown in the figure).

[0047] Figure 4 The figure shows the average decolorization rate after 28 days of formal treatment using the method in Example 3 and Comparative Example 4 (Example in the figure is Example 3);

[0048] Figure 5 The specific methanogenic activity of the method used in Example 3 and Comparative Examples 1-3 is shown in the figure (Example 3 is shown in the figure).

[0049] Wherein, 1: reactor body, 2: degassing tank, 2-1: first space, 2-2: second space, 3: first collection hood, 4: partition net, 5: second collection hood, 6: baffle, 7: exhaust port, 8: first riser pipe, 9: first return pipe, 10: second riser pipe, 11: second return pipe, 12: sampling port, 13-1: first sludge discharge port, 13-2: second sludge discharge port, 14: water inlet pipe, 15: water distributor, 16: water outlet weir, 17: water outlet pipe, 18: water trap, 19: first pump, 20: second pump, 21: first material inlet, 22: second material inlet. Detailed Implementation

[0050] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0051] Example 1

[0052] like Figure 1 As shown, a longitudinal phase separation anaerobic reactor includes: a reactor body 1, an inlet pipe 14, a first collection hood 3, a second collection hood 5, and a degassing tank 2. The reactor body 1 is a closed cylindrical tank. The first collection hood 3 is located below the second collection hood 5. Both the first collection hood 3 and the second collection hood 5 are installed inside the reactor body 1. A first sludge discharge port 13-1 and an inlet are provided on the reactor body 1 below the first collection hood 3. The inlet pipe 14 is located outside the reactor body 1, and one end of the inlet pipe 14 is connected to the inlet for inputting wastewater to be degraded into the reactor body 1. An inlet pump (not shown in the figure) is installed on the inlet pipe 14. A second sludge discharge port 13-2 is provided on the reactor body 1 above the first collection hood 3.

[0053] The degassing tank 2 is located above the reactor body 1. An exhaust port 7 is formed on the degassing tank 2. A baffle 6 is installed inside the degassing tank 2 to divide the interior into a first space 2-1 and a second space 2-2. The first space 2-1 can be approximately cylindrical, and the second space 2-2 can be an annular structure surrounding the first space 2-1. A first riser pipe 8, a second riser pipe 10, a first return pipe 9, and a second return pipe 11 are connected to the degassing tank 2. One end of the first return pipe 9 and one end of the first riser pipe 8 are respectively connected to the first space 2-1. One end of the second return pipe 11 and one end of the second riser pipe 10 are respectively connected to the second space 2-2. The other end of the first return pipe 9 extends into the reactor body 1 and is close to the bottom of the reactor body 1. A return flow is formed on the reactor body 1 between the first collection hood 3 and the second collection hood 5. The inlet and the other end of the second return pipe 11 are connected to the return inlet. The other end of the first riser pipe 8 is connected to the upper part of the first collection hood 3 and a first pump 19 is installed on the first riser pipe 8. The other end of the second riser pipe 10 is connected to the upper part of the second collection hood 5 and a second pump 20 is installed on the second riser pipe 10. The first collection hood 3 and the second collection hood 5 are both tapered from bottom to top, used to sequentially guide the wastewater collected from the first collection hood 3 and the second collection hood 5 into the first riser pipe 8 and the second riser pipe 10. A first gap is formed between the edge of the first collection hood 3 and the inner wall of the reactor body 1, and a separator 4 is installed on the first gap. The separator 4 can be a 35-mesh nylon mesh. A second gap is formed between the edge of the second collection hood 5 and the inner wall of the reactor body 1. An outlet pipe 17 is connected to the reactor body 1 above the second collection hood 5.

[0054] A first material inlet 21 is formed on the reactor body 1 below the first collection hood 3, and a second material inlet 22 is formed on the reactor body 1 between the first collection hood 3 and the second collection hood 5.

[0055] The region of reactor body 1 below the first collection hood 3 constitutes an acid-producing phase, while the region of reactor body 1 between the first collection hood 3 and the second collection hood 5 constitutes a methanogenic phase.

[0056] Example 2

[0057] Based on Example 1, it also includes a water distributor 15 that is connected to the water inlet pipe 14 and located inside the reactor body 1.

[0058] The first space 2-1 and the second space 2-2 are respectively connected to the exhaust port 7, which is used to lead to the outside of the degassing tank 2.

[0059] The lower part of the first space 2-1 and the lower part of the second space 2-2 are separated by a baffle 6, while the upper part of the first space 2-1 and the upper part of the second space 2-2 are connected.

[0060] The reflux inlet is located near the first collection hood 3.

[0061] The position where the first riser pipe 8 is connected to the first space 2-1 is higher than the position where the first return pipe 9 is connected to the first space 2-1, and the position where the second riser pipe 10 is connected to the second space 2-2 is higher than the position where the second return pipe 11 is connected to the second space 2-2.

[0062] The outlet pipe 17 is bent to form a water trap 18, which is used to form a water seal on the outlet pipe 17.

[0063] An outlet weir 16 is installed on the inner wall of the reactor body 1, and the outlet weir 16 is connected to the outlet pipe 17.

[0064] A first valve (not shown in the figure) is installed on the first material inlet 21, and a second valve (not shown in the figure) is installed on the second material inlet 22.

[0065] An insulation layer (not shown in the figure) is installed around the reactor body 1. The insulation layer is a jacket through which hot water is introduced to regulate the temperature inside the reactor body 1. The insulation layer is less affected by the external temperature and can meet the usage requirements of different regions and seasons.

[0066] The first return pipe 9 passes through the first collection shroud 3 and the second collection shroud 5.

[0067] A sampling port 12 is formed on the reactor body 1 below the first collection hood 3.

[0068] Water quality monitoring probes are installed on the reactor body 1 of the acid-producing phase and the methanogenic phase, respectively, to monitor the physicochemical indicators of the wastewater in the corresponding acid-producing phase and methanogenic phase.

[0069] Temperature monitoring devices are installed on the reactor body 1 for both the acid-producing phase and the methanogenic phase.

[0070] Example 3

[0071] The method of using the longitudinal phase separation anaerobic reactor in Example 2 includes the following steps:

[0072] Step 1: Add anaerobic granular sludge to the first sludge discharge port 13-1 and the second sludge discharge port 13-2, so that the volume of anaerobic granular sludge filled between the first collection hood 3 and the second collection hood 5 accounts for 30% of the volume of the methane phase, and the volume of anaerobic granular sludge filled below the first collection hood 3 accounts for 30% of the volume of the acid-producing phase; the anaerobic granular sludge comes from the granular sludge inside the UASB reactor that treats dye wastewater.

[0073] Step 2: Add culture medium into reactor body 1 through water inlet pipe 14 until reactor body 1 is full. Add 1 mol / L hydrochloric acid (HCl) aqueous solution through first material inlet 21 to adjust the pH of acid-producing phase to 5.6. Add 1 mol / L sodium hydroxide (NaOH) aqueous solution through second material inlet 22 to adjust the pH of methanogenic phase to 7.6.

[0074] Step 3: Detect the effluent quality of the acid-producing phase at sampling port 12 until the concentration of volatile acid (calculated as acetic acid in this example) reaches 1500 mg / L, at which point the sludge cultivation in the acid-producing phase ends; Detect the sludge in the methanogenic phase through the second sludge discharge port 13-2 until the specific methanogenic activity of the sludge in the methanogenic phase reaches 50 mL CH4 / (gVSS·d) or higher, at which point the sludge cultivation in the methanogenic phase ends.

[0075] Step 4: Add 1.0g of acid-producing phase medium material per liter of acid-producing phase through the first material inlet 21, and add 1.0g of methanogenic phase medium material per liter of methanogenic phase through the second material inlet 22.

[0076] Step 5, Formal Treatment: Wastewater is introduced into reactor body 1 through inlet pipe 14. The wastewater is actual dye wastewater from a dyeing and printing factory in Shijiazhuang City (azo dye content is approximately 200 mg / L, the main azo dye component is Reactive Red 2). After introduction, the treatment lasts for 28 days. The COD removal rate, decolorization rate, average decolorization rate, and specific methanogenic activity during the 28-day treatment process are as follows: Figures 2-5 As shown.

[0077] In step 2 above, a culture medium is prepared based on the concentration of volatile suspended solids (VSS) a mg / L in the anaerobic granular sludge from step 1. The culture medium includes a main component and a secondary component, and the ratio of the main component to the secondary component by volume is 1000:1. The main components are shown in Table 1, and the secondary components are shown in Table 2.

[0078] Table 1

[0079] principal component Concentration (mg / L) glucose 2000a ammonium chloride 600a Anhydrous calcium chloride 20a Potassium dihydrogen phosphate 40a Sodium bicarbonate 3000 Magnesium chloride hexahydrate 60a water -

[0080] The concentration of sodium bicarbonate in Table 1 does not change with the mass of VSS, but remains at 3000 mg / L, mainly as a buffer to maintain the pH during the reaction.

[0081] Table 2

[0082]

[0083]

[0084] The specific preparation methods for acid-producing phase media materials and methanogenic phase media materials are as follows:

[0085] Preparation method of acid-producing phase medium material: Wash the impurities on the surface of bamboo with deionized water, dry in an air drying oven at 100℃ for 24 hours. After drying, crush in a crusher to form granules that pass through a 20-mesh sieve to obtain bamboo powder. Mix bamboo powder (15g), activator (KHCO3) and thiourea in deionized water (150ml) at a mass ratio of 1:2:1. Stir and react in an 80℃ water bath for 8 hours, then place in an air drying oven at 90℃ for 12 hours. After drying, place in a vacuum tube furnace (OT F-2000X-5L) for pyrolysis: Pour 200mL·min into the vacuum tube furnace. -1 Nitrogen gas was introduced at a flow rate of 10 °C / min to raise the vacuum tube furnace from room temperature. -1 The temperature was increased to 500℃ at a rate of 0.1℃ and held at 500℃ for 2 hours, then naturally cooled to room temperature to obtain the acid-producing phase medium material.

[0086] Preparation method of methanogenic phase media material: Bamboo surface impurities are washed with deionized water and dried in an air drying oven at 100℃ for 24 hours. After drying, it is crushed into granules through a 20-mesh sieve to obtain bamboo powder. In deionized water (150ml), bamboo powder (30g), activator (KHCO3), and nitrogen source (urea) are uniformly mixed at a mass ratio of 2:2:1. The mixture is stirred and reacted in an 80℃ water bath for 8 hours, then dried in an air drying oven at 90℃ for 12 hours. After drying, it is placed in a vacuum tube furnace (OT F-2000X-5L) for pyrolysis: 200mL·min⁻¹ is added to the vacuum tube furnace. -1 Nitrogen gas was introduced at a flow rate of 10 °C / min, and the vacuum tube furnace was heated from room temperature to 600 °C (temperature uncertainty within 0.1 °C) and held at 600 °C for 2 hours. The mixture was then naturally cooled to room temperature to obtain the intermediate product. The intermediate product was washed with 1 mol / L hydrochloric acid, filtered, and washed with deionized water until the filtrate was neutral. It was then dried at 80 °C for 10 hours. The intermediate product (10 g) was then mixed uniformly with K₂FeO₄ at a mass ratio of 1:0.4 in 150 ml of deionized water. The mixture was placed in a water bath and stirred for 4 hours at 80 °C. It was then dried at 80 °C for 10 hours using a blower. Finally, it was placed in a vacuum tube furnace (OT F-2000X-5L) for high-temperature calcination: 200 mL / min was introduced into the vacuum tube furnace. -1 Nitrogen gas was introduced at a flow rate of 10℃ / min to heat the vacuum tube furnace from room temperature to 600℃ (temperature uncertainty within 0.1℃), and the furnace was held at 600℃ for 1 hour. The furnace was then naturally cooled to room temperature to obtain the methanogenic phase medium material.

[0087] In the above-described operation, wastewater enters the distributor and is evenly distributed at the bottom of the acid-producing phase, mixing uniformly with the acid-producing sludge and medium material. The biogas generated by the acid-producing phase is collected by the first collection hood 3 and sent to the degassing tank 2. After the wastewater flows upward to the first collection hood 3, part of the wastewater is lifted by the first pump 19 through the first riser pipe 8 to the degassing tank 2 to complete gas-liquid separation. The gas is collected, and under the action of gravity, the wastewater in the first space 2-1 flows back to the bottom of the acid-producing phase through the first return pipe 9 to dilute the influent wastewater and improve the system mass transfer rate. Wastewater flowing through the separator 4 mixes with the methanogenic sludge and media material in the methanogenic phase, generating a large amount of biogas. This biogas is collected in the degassing tank via the second collection hood 5. In the second space 2-2, after flowing to the second collection hood 5, a portion of the sludge-water mixture, driven by the second pump 20, is lifted through the second riser 10 to the degassing tank 2 for gas-liquid separation and gas collection. The sludge-water mixture, under gravity, flows back to the bottom of the methanogenic phase via the second return pipe 11, completing wastewater dilution and circulating mass transfer. The remaining wastewater flows upwards, undergoing sedimentation in the upper part of the second collection hood 5. The settled sludge returns to the methanogenic phase, and the treated wastewater is discharged through the effluent weir and water seal along the effluent pipe.

[0088] Comparative Example 1

[0089] A controllable dual-cycle anaerobic reactor (its structure is shown in publication number CN105753147A, and all names below refer to those in CN105753147A), the method of using it includes the following steps:

[0090] Step 1: Inoculate the first reaction zone of the controllable dual-circulation anaerobic reactor with flocculent sludge from a municipal wastewater treatment plant that treats dye wastewater. The flocculent sludge accounts for 33% of the internal volume of the controllable dual-circulation anaerobic reactor.

[0091] Step 2: Wastewater of the same source and volume as in Example 3 is input into the controllable dual-circulation anaerobic reactor via an inlet pump and distributor, allowing the wastewater to mix evenly with the flocculent sludge. The biogas produced in the first reaction zone is collected by the primary three-phase separator. Since the biogas produced in the early stage of the reaction is insufficient to drive the internal circulation of the reactor, the valve on the internal circulation riser is closed, while the two valves on the internal circulation conversion pipe are opened and the internal circulation control pump is turned on. The internal circulation control pump drives the gas-liquid mixture in the pipeline to the inner layer of the degassing tank. The separated biogas is discharged from the top of the degassing tank, and the sludge-water mixture returns to the bottom of the first reaction zone along the internal circulation downcomer, completing the controllable internal circulation. After treatment in the first reaction zone, the wastewater automatically enters the second reaction zone for further treatment. The biogas produced in the second reaction zone is collected by a two-stage three-phase separator. Since the biogas produced in the early stage of the reaction is insufficient to drive the external circulation, the valve on the external circulation riser pipe is closed, while the two valves on the external circulation conversion pipe are opened, and the external circulation control pump is activated. The external circulation control pump drives the gas-liquid mixture in the pipeline to the outer layer of the degassing tank. The separated biogas is discharged from the top of the degassing tank, and the mud-water mixture returns to the bottom of the second reaction zone along the internal circulation downcomer, completing the controlled external circulation. In the sedimentation zone, the mud-water mixture undergoes solid-liquid separation. The treated wastewater supernatant is discharged through the effluent weir and effluent pipe, while the settled sludge is returned to the second reaction zone.

[0092] Step 3: After 110 days of reaction, the flocculent sludge in the controllable dual-circulation anaerobic reactor gradually forms granular sludge, and the wastewater treatment efficiency stabilizes, completing the reactor startup. Simultaneously, biogas production gradually increases. When the biogas is sufficient to drive both the internal and external circulation, the internal and external circulation control pumps are shut off, the valves on the internal and external circulation switching pipes are closed, and the valves on the internal and external circulation riser pipes are opened, achieving self-driven circulation in the reactor (at this point, the controllable dual-circulation anaerobic reactor startup is complete).

[0093] After the controlled dual-cycle anaerobic reactor is started up, a formal degradation process will be carried out for 28 days. The COD removal rate, decolorization rate, and specific methanogenic activity during the formal degradation process are as follows: Figure 2 , 3 As shown in Figure 5, the hydraulic retention time of the wastewater input into the controllable dual-circulation anaerobic reactor is 24 hours.

[0094] The wastewater treated by the controllable dual-circulation anaerobic reactor is the same as that in Example 3, which is the actual dye wastewater from a printing and dyeing factory in Shijiazhuang City (the azo dye content is about 200 mg / L, and the main azo dye component is Reactive Red 2).

[0095] In terms of processing efficiency, such as Figure 2As shown, the method used in Example 3 can achieve a COD removal rate of up to about 95% during the stable operation period of formal treatment, which is 27% higher than the method of using the controllable dual-cycle anaerobic reactor in Comparative Example 1. The decolorization rate of Example 3 can reach up to 95.8%, which is 26.9% higher than the controllable dual-cycle anaerobic reactor in Comparative Example 1.

[0096] like Figure 5 As shown, the granular sludge in the methanogenic phase of Example 3 had a specific methanogenic activity (SMA) of 7.5 ml / (gVSS·h) during the stable operation period of formal treatment, which was 41% higher than that of the sludge in the controllable dual-cycle anaerobic reactor in Comparative Example 1.

[0097] The method used in Example 3 achieved a methane yield of up to 67%, which is 16% higher than the controlled dual-cycle anaerobic reactor in Comparative Example 1.

[0098] In Comparative Example 1, the concentration of volatile fatty acids (VFAs) during the stable operation period of the formal treatment was 800-1000 mg / L, of which the concentration of propionic acid was 200-300 mg / L. In Example 3, the concentration of volatile fatty acids in the controlled dual-cycle anaerobic reactor during the stable operation period of the formal treatment was 300-500 mg / L, of which the concentration of propionic acid was 60-100 mg / L. The accumulation of VFAs, especially propionic acid, can easily lead to reactor acidification or even collapse. Therefore, it can be seen that the method of the present invention has better operational stability for azo dye wastewater. The present invention has greatly improved the degradation effect of azo dye wastewater by adjusting the electron transfer angle and improving the method of use.

[0099] Comparative Example 2

[0100] The method of using the longitudinal phase separation anaerobic reactor in Example 2 is basically the same as that in Example 3, except that step 4 is replaced with "Step 4: Add 1.0g of methanogenic phase medium material per liter of methanogenic phase through the second material inlet 22;" (i.e., no acidogenic phase medium material is added).

[0101] Comparative Example 3

[0102] The method of using the longitudinal phase separation anaerobic reactor in Example 2 is basically the same as that in Example 3, except that step 4 is replaced with "Step 4: Add 1.0g of acid-producing phase medium material per liter of acid-producing phase through the first material inlet 21;" (i.e., no methanogenic phase medium material is added).

[0103] Comparing the COD removal and decolorization rates during the 28-day treatment process in step 5 of Examples 3 and Comparative Examples 2-3, the COD removal rate of Example 3 was approximately 17% higher than that of Comparative Example 2, and the decolorization rate was approximately 18.9% higher; the COD removal rate of Example 3 was approximately 10% higher than that of Comparative Example 3, and the decolorization rate was approximately 10.5% higher. Therefore, it can be seen that the acid-producing phase medium material and the methanogenic phase medium material used in the method of the present invention have significantly improved treatment efficiency and exhibit a certain synergistic treatment effect.

[0104] Comparative Example 4

[0105] The method of using the longitudinal phase separation anaerobic reactor in Example 2 is basically the same as that in Example 3, except that step 4 is replaced by "adding 1.0g of methanogenic phase medium material to each liter of acid-producing phase through the first material inlet 21, and adding 1.0g of acid-producing phase medium material to each liter of methanogenic phase through the second material inlet 22".

[0106] Tests showed that the decolorization rate of the method used in Example 3 reached 94.3%, which is 6.1% higher than that of Comparative Example 4.

[0107] In addition, Example 3 can begin formal wastewater treatment in just 7-10 days, which greatly shortens the reactor start-up time compared to Comparative Example 1 (which takes 3 months to form granular sludge).

[0108] By adding acid-producing and methanogenic media materials in separate phases, the inhibitory effect of toxic pollutants is alleviated. Under the impact of wastewater, the longitudinal phase separation anaerobic reactor can resume stable operation in a short time.

[0109] The acid-producing phase medium material is SN-BC, which enhances the electron transfer process between microorganisms and pollutants. Because large molecular pollutants cannot enter the microorganisms, during degradation, electrons are typically released by the microorganisms and transferred to the pollutants, leading to their reduction into smaller molecules. The sulfur element in the acid-producing phase medium material mainly takes the form of thiophene sulfide (CSC) and C-SO4. X The presence of -C and the formation of N and S synergistic effects further enhance the electrochemical properties of SN-BC, giving SN-BC better redox performance. Its enhanced electron shuttle mechanism can promote electron transfer between microorganisms and pollutants, create new electron flow pathways in microbial energy metabolism, drive changes in microbial community composition, thereby accelerating the degradation of pollutants and energy recovery.

[0110] The methanogenic phase medium material is Fe-N-BC, which enhances the electron transfer process between microorganisms, i.e., promotes interspecies electron transfer in a mutualistic symbiotic relationship between microorganisms. This electron transfer method is not limited by transmembrane transport; insoluble macromolecular electron acceptors can be reduced extracellularly. Furthermore, as a conductive material, Fe-N-BC's conductivity is further improved through metal loading. Simultaneously, Fe... 2+ / Fe 3+ The presence of Fe-N-BC also enhances the redox performance of Fe-N-BC and accelerates the interspecies electron transfer rate, thereby increasing the rate of anaerobic digestion.

[0111] The present invention has been described above by way of example. It should be noted that any simple modifications, alterations or other equivalent substitutions that can be made by those skilled in the art without creative effort without departing from the core of the present invention fall within the protection scope of the present invention.

Claims

1. A method of using a longitudinal phase separation anaerobic reactor, the longitudinal phase separation anaerobic reactor comprising: The reactor body (1), inlet pipe (14), first collection hood (3), second collection hood (5), and degassing tank (2) are provided. The reactor body (1) is a sealed tank. The first collection hood (3) is located below the second collection hood (5). Both the first collection hood (3) and the second collection hood (5) are installed inside the reactor body (1). A first sludge discharge port (13-1) and an inlet are provided on the reactor body (1) below the first collection hood (3). The inlet pipe (14) is located outside the reactor body (1), and one end of the inlet pipe (14) is connected to the inlet for inputting wastewater to be degraded into the reactor body (1). A second sludge discharge port (13-2) is provided on the reactor body (1) above the first collection hood (3). The degassing tank (2) is located above the reactor body (1). An exhaust port (7) is formed on the degassing tank (2). A baffle (6) is provided inside the degassing tank (2) to divide the degassing tank (2) into a first space (2-1) and a second space (2-2). A first riser pipe (8), a second riser pipe (10), a first return pipe (9), and a second return pipe (11) are connected to the degassing tank (2). One end of the first return pipe (9) and one end of the first riser pipe (8) are respectively connected to the first space. In space (2-1), one end of the second reflux pipe (11) and one end of the second riser pipe (10) are respectively connected to the second space (2-2). The other end of the first reflux pipe (9) extends into the reactor body (1) and is close to the bottom of the reactor body (1). A reflux inlet is formed on the reactor body (1) between the first collection hood (3) and the second collection hood (5). The other end of the second reflux pipe (11) is connected to the reflux inlet. The other end of the first riser pipe (8) is connected to the first collection hood (5). The upper part of the cover (3) is connected and a first pump (19) is installed on the first riser pipe (8). The other end of the second riser pipe (10) is connected to the upper part of the second collection cover (5) and a second pump (20) is installed on the second riser pipe (10). The first collection cover (3) and the second collection cover (5) are both tapered from bottom to top, used to sequentially guide the wastewater collected from the first collection cover (3) and the second collection cover (5) into the first riser pipe (8) and the second riser pipe (10). The edge of the first collection cover (3) is connected to the upper part of the second collection cover (5). A first gap is formed between the inner walls of the reactor body (1) and a 30-40 mesh partition net (4) is installed on the first gap. An acid-producing phase is formed in the region of the reactor body (1) below the first collection hood (3), and a methanogenic phase is formed in the region of the reactor body (1) between the first collection hood (3) and the second collection hood (5). A second gap is formed between the edge of the second collection hood (5) and the inner wall of the reactor body (1). A water outlet pipe (17) is connected to the reactor body (1) above the second collection hood (5). A first material inlet (21) is formed on the reactor body (1) below the first collection hood (3), and a second material inlet (22) is formed on the reactor body (1) between the first collection hood (3) and the second collection hood (5); characterized in that, The method of using a longitudinal phase separation anaerobic reactor includes the following steps: Step 1: Add anaerobic granular sludge to the first sludge discharge port (13-1) and the second sludge discharge port (13-2) so that the volume of anaerobic granular sludge filled between the first collection hood (3) and the second collection hood (5) accounts for 25-35% of the volume of the methane phase, and the volume of anaerobic granular sludge filled below the first collection hood (3) accounts for 25-35% of the volume of the acid-producing phase. Step 2: Add culture medium into the reactor body (1) through the water inlet pipe (14) until the reactor body (1) is full, adjust the pH of the acid-producing phase to 5.5-6, and adjust the pH of the methanogenic phase to 7.5-7.8; Step 3: Test the effluent quality of the acid-producing phase until the volatile acid concentration reaches 1500 mg / L, at which point the sludge culture in the acid-producing phase ends; and until the specific methanogenic activity of the sludge in the methanogenic phase reaches 50 mL CH4 / (gVSS·d) or higher, at which point the sludge culture in the methanogenic phase ends. Step 4: Add acid-producing phase mediating material to the acid-producing phase and add methanogenic phase mediating material to the methanogenic phase; Step 5, Formal Treatment: Wastewater is introduced into the reactor body (1) through the inlet pipe (14); Preparation method of acid-producing phase medium material: bamboo powder, KHCO3 as activator and thiourea are uniformly mixed in deionized water at a mass ratio of 1:2:(0.8-1.2), stirred and reacted, dried, and then kept at 480-520℃ for 1.5-2.5h in a nitrogen or inert gas environment, and naturally cooled to room temperature to obtain acid-producing phase medium material; Preparation method of methanogenic phase medium material: In deionized water, bamboo powder, KHCO3 as activator and nitrogen source are uniformly mixed in a mass ratio of 2:2:(0.8-1.2), stirred and reacted, dried, and then pyrolyzed: under nitrogen or inert gas environment, it is kept at 580-620℃ for 1.5-2.5h, and then naturally cooled to room temperature to obtain intermediate product; the intermediate product is acid washed, filtered, washed with deionized water until the filtrate is neutral, dried, and then the intermediate product and K2FeO4 are uniformly mixed in deionized water in a mass ratio of 1:(0.3-0.5), stirred and reacted, dried, and then calcined at high temperature: under nitrogen or inert gas environment, it is kept at 580-620℃ for 1.5-2.5h, and then naturally cooled to room temperature to obtain methanogenic phase medium material.

2. The method of use according to claim 1, characterized in that, The pickling process uses a 0.5-1 mol / L hydrochloric acid aqueous solution.

3. The method of use according to claim 1, characterized in that, The nitrogen source is urea; The bamboo powder has a particle size of 10-40 mesh; The stirring reaction is carried out by stirring in a water bath at 80–100°C for 4–10 hours.

4. The method of use according to claim 1, characterized in that, In step 4, the mass of the acid-producing phase medium material added per liter of acid-producing phase is 1-2g, and the mass of the methanogenic phase medium material added per liter of methanogenic phase is 1-2g.

5. The method of use according to claim 1, characterized in that, In step 2, a culture medium is prepared according to the concentration of volatile suspended solids a mg / L in the anaerobic granular sludge. The culture medium includes a main component and an auxiliary component, and the ratio of the main component to the auxiliary component by volume is 1000:

1.

6. The method of use according to claim 1, characterized in that, The longitudinal phase separation anaerobic reactor also includes: a water distributor (15) connected to the inlet pipe (14) and located inside the reactor body (1); The first space (2-1) and the second space (2-2) are respectively connected to the exhaust port (7); The lower part of the first space (2-1) and the lower part of the second space (2-2) are separated by the baffle (6), and the upper part of the first space (2-1) and the upper part of the second space (2-2) are connected.

7. The method of use according to claim 1, characterized in that, The reflux inlet is located near the first collection hood (3).

8. The method of use according to claim 1, characterized in that, The position where the first riser (8) is connected to the first space (2-1) is higher than the position where the first return pipe (9) is connected to the first space (2-1), and the position where the second riser (10) is connected to the second space (2-2) is higher than the position where the second return pipe (11) is connected to the second space (2-2).

9. The method of use according to claim 1, characterized in that, The outlet pipe (17) is bent to form a water trap (18), which is used to form a water seal on the outlet pipe (17); A water outlet weir (16) is installed on the inner wall of the reactor body (1), and the water outlet weir (16) is connected to the water outlet pipe (17).

10. The method of use according to claim 1, characterized in that, A first valve is installed on the first material inlet (21), and a second valve is installed on the second material inlet (22); An insulation layer is installed around the reactor body (1); The first return pipe (9) passes through the first collection hood (3) and the second collection hood (5).

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