A multi-stage hydrolysis-acidification coupled electrocatalytic device and hydrolysis-acidification method

Abstract

The present application proposes a multi-stage hydrolysis and acidification coupled electrocatalytic device and a hydrolysis and acidification method, the device comprising: a multi-stage hydrolysis and acidification reactor, the pretreated raw water is connected to the water inlet of the first and / or second hydrolysis and acidification reactors through a water pipe, and the water inlet of the next hydrolysis and acidification reactor is connected to the water outlet of the previous hydrolysis and acidification reactor; a multi-stage electrocatalytic reactor, the multi-stage hydrolysis and acidification reactors are respectively connected to the corresponding electrocatalytic reactors through a reflux system, the electrocatalytic reactors have an electrode area, and the sewage in the hydrolysis and acidification reactors passes through the electrode area in the electrocatalytic reactors and returns to the corresponding hydrolysis and acidification reactors. The present application performs multi-stage hydrolysis and acidification and electrocatalytic reactions on the sewage through the arrangement of a multi-stage hydrolysis and acidification reactor and a multi-stage electrocatalytic reactor, so that the macromolecular organic matter in the raw water is decomposed by chain scission step by step, which accelerates the hydrolysis and acidification reaction and improves the efficiency of chain scission decomposition of pollutants.

Description

Technical Field

[0001] The present application relates to the field of industrial wastewater treatment, and in particular to a multi-stage hydrolysis-acidification coupled electrocatalytic device and a hydrolysis-acidification method. Background Art

[0002] Rapid industrial development has also brought new environmental challenges. my country produces enormous amounts of industrial wastewater, with the printing and dyeing, papermaking, chemical, leather, and coal chemical industries accounting for half of the total. This industrial wastewater is characterized by high concentrations, poor biodegradability, complex composition, the presence of toxic and hazardous substances, and difficulty in degradation, as well as significant fluctuations in water quality. Consequently, the difficulty and cost of treating industrial wastewater have increased dramatically.

[0003] Hydrolysis and acidification involves the fermentation and decomposition of insoluble and soluble, long-chain organic matter in wastewater into short-chain soluble organic matter, such as volatile fatty acids (VFAs) and alcohols, by hydrolytic and acidifying bacteria. Hydrolysis and acidification technology is widely used in industrial wastewater pretreatment due to its advantages, including improved biodegradability, resistance to shock loads, and low capital investment and operation and maintenance costs. However, traditional hydrolysis and acidification processes suffer from slow reactions and low efficiency in pollutant chain scission. Summary of the Invention

[0004] The present invention provides a multi-stage hydrolysis-acidification coupled electrocatalytic device and a hydrolysis-acidification method to solve the problems existing in the related art. The technical solution is as follows:

[0005] In a first aspect, an embodiment of the present application provides a multi-stage hydrolysis-acidification coupled electrocatalytic device, comprising:

[0006] Multi-stage hydrolysis acidification reactor, the pretreated raw water is connected to the water inlet of the first and / or second hydrolysis acidification reactor through a water pipe, and the water inlet of the next hydrolysis acidification reactor is connected to the water outlet of the previous hydrolysis acidification reactor;

[0007] Multi-stage electrocatalytic reactor, multi-stage hydrolysis acidification reactor is connected to the corresponding electrocatalytic reactor through a reflux system. The electrocatalytic reactor has an electrode area. The sewage in the hydrolysis acidification reactor passes through the electrode area in the electrocatalytic reactor and returns to the corresponding hydrolysis acidification reactor.

[0008] In one embodiment, the hydrolysis and acidification reactor includes a hydrolysis and acidification reaction tank body, a water inlet system, a water distribution system and a water outlet system. The water inlet of the water inlet system is connected to the water pipe, and / or the water inlet of the water inlet system is connected to the water outlet of the water outlet system of the upper-level hydrolysis and acidification reactor. The water distribution system is fixed in the hydrolysis and acidification reaction tank body, the water outlet of the water inlet system is connected to the water distribution system, and the sewage in the electrocatalytic reactor is returned to the water distribution system through the reflux system.

[0009] In one embodiment, the water distribution system includes an adjustable water distributor, a central vertical shaft and a water distribution system. The central vertical shaft is located in the hydrolysis and acidification reaction tank body. The top of the central vertical shaft is connected to the adjustable water distributor, the bottom of the central vertical shaft is connected to the water distribution system, and the outlet of the water inlet system is connected to the interior of the central vertical shaft.

[0010] In one embodiment, the reflux system includes a first reflux pipe, a second reflux pipe and a reflux pump, the reflux inlet of the first reflux pipe is located in the hydrolysis and acidification reaction tank body, the reflux outlet of the first reflux pipe is connected to the interior of the electrocatalytic reactor, the reflux inlet of the second reflux pipe is connected to the interior of the electrocatalytic reactor, the reflux pump is connected to the second reflux pipe, and the reflux pump returns the sewage in the electrocatalytic reactor to the adjustable water distributor through the second reflux pipe.

[0011] In one embodiment, the hydrolysis acidification reactor further includes a sludge discharge system, which is placed at the bottom of the hydrolysis acidification reaction tank body, and the sludge at the bottom of the hydrolysis acidification reaction tank body is discharged through the sludge discharge system; the effluent system is located at the top inner side of the hydrolysis acidification reaction tank body, and the treated sewage in the hydrolysis acidification reaction tank body is discharged through the effluent system.

[0012] In one embodiment, the electrocatalytic reactor includes an electrocatalytic reaction cell body and an electrode assembly. The electrocatalytic reaction cell body also has an electrode water inlet area and an electrode water outlet area. The electrode area is located between the electrode water inlet area and the electrode water outlet area, and the electrode assembly is placed in the electrode area.

[0013] In one embodiment, the electrocatalytic reactor further includes a power supply system, which includes a junction box and a voltage-stabilized power supply. The voltage-stabilized power supply is connected to the electrode assembly through the junction box, and the voltage-stabilized power supply provides a stable low-voltage power supply for the electrode assembly.

[0014] In one embodiment, the electrocatalytic reactor further includes an aeration system, which includes a blower, an air inlet main pipe, multiple air inlet branches and multiple microporous aeration tubes. The air outlet of the blower is connected to the air inlet of the air inlet main pipe, the multiple air inlet branches are respectively connected to the air inlet main pipe, the multiple microporous aeration tubes are respectively connected to the air outlets of the multiple air inlet branches, and the multiple air inlet branches are all provided with ball valves; the electrode water outlet area and the electrode water inlet area are both provided with an ORP detector and a pH probe.

[0015] In one embodiment, the electrode assembly includes an anode electrode plate and a cathode electrode plate that are spaced apart. Electrocatalytic fillers are provided on both the anode electrode plate and the cathode electrode plate. The electrocatalytic fillers are made of modified carbon fiber and nylon material.

[0016] In a second aspect, the present invention provides a hydrolysis and acidification method, comprising the following steps:

[0017] The pretreated sewage enters the primary hydrolysis and acidification reactor for hydrolysis and acidification reaction;

[0018] The sewage in the primary hydrolysis acidification reactor enters the corresponding primary electrocatalytic reactor through the reflux system to undergo electrocatalytic reaction;

[0019] The sewage in the primary electrocatalytic reactor enters the primary hydrolysis and acidification reactor again through the reflux system for hydrolysis and acidification;

[0020] The wastewater after primary hydrolysis in the primary hydrolysis acidification reactor enters the secondary hydrolysis acidification reactor for hydrolysis and acidification reaction;

[0021] The wastewater in the secondary hydrolysis acidification reactor enters the corresponding secondary electrocatalytic reactor through the reflux system for electrocatalytic reaction;

[0022] The sewage in the secondary electrocatalytic reactor enters the secondary hydrolysis and acidification reactor again through the reflux system for hydrolysis and acidification;

[0023] The wastewater after secondary hydrolysis in the secondary hydrolysis acidification reactor enters the tertiary hydrolysis acidification reactor for hydrolysis and acidification reaction;

[0024] The sewage in the three-stage hydrolysis acidification reactor enters the corresponding three-stage electrocatalytic reactor through the reflux system to carry out electrocatalytic reaction;

[0025] The sewage in the three-stage electrocatalytic reactor enters the three-stage hydrolysis acidification reactor again through the reflux system for hydrolysis and acidification, completing the three-stage hydrolysis and acidification.

[0026] The advantages or beneficial effects of the above technical solution include at least:

[0027] The multi-stage hydrolysis and acidification coupled electrocatalytic device of the present application includes a multi-stage hydrolysis and acidification reactor and a multi-stage electrocatalytic reactor, and the hydrolysis and acidification reactor of each stage is connected to the corresponding electrocatalytic reactor through a reflux system. When the multi-stage hydrolysis and acidification coupled electrocatalytic device is in use, the pretreated raw water first enters the primary hydrolysis and acidification reactor for the primary hydrolysis and acidification reaction, and at the same time, the sewage in the primary hydrolysis and acidification reactor enters the primary electrocatalytic reactor through the reflux system for the electrocatalytic reaction. The sewage after the electrocatalytic reaction in the primary electrocatalytic reactor enters the primary hydrolysis and acidification reactor again through the reflux system for the hydrolysis and acidification reaction. The sewage after the acidification reaction in the primary hydrolysis and acidification reactor enters the secondary hydrolysis and acidification reactor for hydrolysis and acidification, and at the same time as the secondary hydrolysis and acidification, the sewage enters the secondary electrocatalytic reactor for electrocatalytic reaction. The sewage after the acidification reaction in the secondary hydrolysis and acidification reactor enters the tertiary hydrolysis and acidification reactor for hydrolysis and acidification, and at the same time as the tertiary hydrolysis and acidification, the sewage enters the tertiary electrocatalytic reactor for electrocatalytic reaction.

[0028] The present application performs multi-stage hydrolysis and acidification and electrocatalytic reactions on sewage by setting up a multi-stage hydrolysis and acidification reactor and a multi-stage electrocatalytic reactor, so that the macromolecular organic matter in the raw water is decomposed by chain breaking step by step, accelerating the hydrolysis and acidification reaction, improving the chain breaking decomposition efficiency of pollutants, and improving the biodegradability of sewage.

[0029] The above summary is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present application will be readily apparent by reference to the accompanying drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar components or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0031] Figure 1 It is a schematic diagram of the structure of a multi-stage hydrolysis-acidification coupled electrocatalytic device;

[0032] Figure 2 is a structural schematic diagram of an electrode assembly;

[0033] Figure 3 It is the structural diagram of the aeration system;

[0034] Figure 4 This is a comparison chart of COD removal rate effects;

[0035] Description of reference numerals:

[0036] 1. Hydrolysis and acidification reactor; 2. Electrocatalytic reactor; 3. Water pipe; 4. Reflux system; 11. Primary hydrolysis and acidification reactor; 12. Secondary hydrolysis and acidification reactor; 13. Tertiary hydrolysis and acidification reactor; 21. Primary electrocatalytic reactor; 22. Secondary electrocatalytic reactor; 23. Tertiary electrocatalytic reactor; 14. Hydrolysis and acidification reaction tank; 15. Water inlet system; 16. Water distribution system; 17. Water outlet system; 160. Adjustable water distributor; 161. Central shaft; 162. Water distribution system; 151. Water inlet pipe ;41. First return line;42. Second return line;43. Return pump;171. Outlet weir;18. Mud discharge system;24. Electrocatalytic reaction cell body;25. Electrode assembly;26. Power supply system;27. Aeration system;251. Anode electrode plate;252. Cathode electrode plate;253. Electrode bracket;254. Electrocatalytic filler;271. Blower;272. Air intake main pipe;273. Air intake branch pipe;274. Microporous aeration tube;275. Ball valve;28. ORP detector;29. pH probe. DETAILED DESCRIPTION

[0037] Hereinafter, only certain exemplary embodiments are briefly described. As will be appreciated by those skilled in the art, the described embodiments may be modified in various ways without departing from the spirit or scope of the present application. Therefore, the drawings and description are to be regarded as illustrative in nature and not restrictive.

[0038] Example 1

[0039] Electrocatalysis involves applying a low-voltage electric field to an electrocatalytic reactor to promote the accumulation of microorganisms on the surface of the carrier, accelerate electron transfer within the reaction system, and promote the fermentation, chain scission, and decomposition of pollutants. Electrocatalysis is a highly efficient and energy-efficient biological treatment technology that can promote hydrolysis and acidification reactions.

[0040] like Figure 1 As shown, based on the above advantages of electrocatalytic technology, an embodiment of the present application provides a multi-stage hydrolysis and acidification coupled electrocatalytic device, including a multi-stage hydrolysis and acidification reactor 1 and a multi-stage electrocatalytic reactor 2. The pretreated raw water is connected to the water inlet of the first and / or second hydrolysis and acidification reactor 1 through a water pipe 3, and the water inlet of the next hydrolysis and acidification reactor 1 is connected to the water outlet of the previous hydrolysis and acidification reactor 1. The multi-stage hydrolysis and acidification reactor 1 is connected to the corresponding electrocatalytic reactor 2 through a reflux system 4. The electrocatalytic reactor 2 has an electrode area. The sewage in the hydrolysis and acidification reactor 1 passes through the electrode area in the electrocatalytic reactor 2 and returns to the corresponding hydrolysis and acidification reactor 1. The above-mentioned pretreated raw water refers to the sewage to be hydrolyzed and acidified.

[0041] In one embodiment, when the multi-stage hydrolysis-acidification coupled electrocatalytic device is a three-stage hydrolysis-acidification coupled electrocatalytic device, the hydrolysis-acidification reactor 1 includes a primary hydrolysis-acidification reactor 11, a secondary hydrolysis-acidification reactor 12, and a tertiary hydrolysis-acidification reactor 13. The electrocatalytic reactor 2 includes a primary electrocatalytic reactor 21, a secondary electrocatalytic reactor 22, and a tertiary electrocatalytic reactor 23. The primary hydrolysis-acidification reactor 11 is connected to the primary electrocatalytic reactor 21 via a reflux system 4, the secondary hydrolysis-acidification reactor 12 is connected to the secondary electrocatalytic reactor 22, and the tertiary hydrolysis-acidification reactor 13 is connected to the tertiary electrocatalytic reactor 23. The water inlet of the secondary hydrolysis-acidification reactor 12 is connected to the water outlet of the primary hydrolysis-acidification reactor 11, and the water inlet of the tertiary hydrolysis-acidification reactor 13 is connected to the water outlet of the secondary hydrolysis-acidification reactor 12.

[0042] The pretreated raw water is connected to the primary hydrolysis acidification reactor 11 via the water pipe 3. The pretreated raw water can also be connected to the primary hydrolysis acidification reactor 11 and the secondary hydrolysis acidification reactor 12 via the water pipe 3. In one embodiment, the pretreated raw water can be directly transported to the primary hydrolysis acidification reactor 11 via the water pipe 3. In another embodiment, the pretreated raw water can be transported to the primary hydrolysis acidification reactor 11 via the water pipe 3, or the pretreated raw water can be transported to the primary hydrolysis acidification reactor 11 or the secondary hydrolysis acidification reactor 12 via the water pipe 3.

[0043] To hydrolyze and acidify the wastewater, the primary hydrolysis and acidification reactor 11, the secondary hydrolysis and acidification reactor 12, and the tertiary hydrolysis and acidification reactor 13 each include a hydrolysis and acidification reaction tank body 14, a water inlet system 15, a water distribution system 16, and a water outlet system 17. The water inlet of the water inlet system 15 is connected to the water pipe 3, and / or the water inlet of the water inlet system 15 is connected to the water outlet of the water outlet system 17 of the previous hydrolysis and acidification reactor 11. The water distribution system 16 is fixed within the hydrolysis and acidification reaction tank body 14, and the water outlet of the water inlet system 15 is connected to the water distribution system 16. The wastewater in the electrocatalytic reactor is returned to the water distribution system 16 via the reflux system 4.

[0044] Furthermore, the water inlet system 15 includes a water inlet pipe 151. The sewage can be transported to the water inlet pipe 151 through a water pump and then enter the water distribution system 16 through the water inlet pipe 151. The height difference can also be used to realize the transportation of sewage under the action of gravity.

[0045] The water distribution system 16 is used to evenly distribute the pretreated raw water or the effluent from the previous hydrolysis and acidification process in the hydrolysis and acidification reaction tank body 14. The water distribution system 16 includes an adjustable water distributor 160, a central shaft 161, and a water distribution system 162. The central shaft 161 is located in the hydrolysis and acidification reaction tank body 14, the top of the central shaft 161 is connected to the adjustable water distributor 160, the bottom of the central shaft 161 is connected to the water distribution system 162, and the outlet of the water inlet pipe 151 of the water inlet system 15 is connected to the interior of the central shaft 161. In the primary hydrolysis and acidification reactor 11, the pretreated raw water is directly transported to the central shaft 161 through the water inlet system 15. In the secondary hydrolysis and acidification reactor 12, the sewage after the primary hydrolysis and acidification enters the central shaft 161 of the secondary hydrolysis and acidification reactor 12 through the water inlet system 15. In the tertiary hydrolysis and acidification reactor 13, the wastewater after the secondary hydrolysis and acidification enters the central vertical shaft 161 of the tertiary hydrolysis and acidification reactor 13 through the water inlet system 15. In one embodiment, in the secondary hydrolysis and acidification reactor 12, both the pretreated raw water and the wastewater after the primary hydrolysis and acidification enter directly into the central vertical shaft 161 of the secondary hydrolysis and acidification reactor 12 through the water inlet system 15.

[0046] The water distribution system 162 and adjustable water distributor 160 of this embodiment are identical to those disclosed in CN218709575. Water distribution system 162 is located at the bottom of central shaft 161. After sewage from central shaft 161 enters water distribution system 162, it distributes the sewage.

[0047] The reflux system 4 includes a first reflux line 41, a second reflux line 42, and a reflux pump 43. The reflux inlet of the first reflux line 41 is located within the hydrolysis and acidification reaction cell body 14, and the reflux outlet of the first reflux line 41 is connected to the interior of the electrocatalytic reactor 2. The sewage in the hydrolysis and acidification reaction cell body 14 can be transported to the electrocatalytic reaction cell body 24 by a water pump. The reflux inlet of the second reflux line 42 is connected to the interior of the electrocatalytic reactor 2. The reflux pump 43 is connected to the second reflux line 42. The reflux pump 43 returns the sewage in the electrocatalytic reactor 2 to the adjustable water distributor 160 through the second reflux line 42. The adjustable water distributor 160 is placed at the top of the hydrolysis and acidification reaction cell body 14. The refluxed sewage enters the central shaft 161 through the adjustable water distributor 160, and then enters the water distribution system 162 through the central shaft 161. The sewage is distributed to the hydrolysis and acidification reaction cell body 14 through the water distribution system 162.

[0048] The effluent system 17 is located at the top of the hydrolysis and acidification reaction tank body 14. The treated wastewater in the hydrolysis and acidification reaction tank body 14 is discharged through the effluent system 17. The effluent system 17 includes multiple parallel effluent weirs 171. The hydrolysis and acidification wastewater enters the effluent weirs 171 and is discharged through the drain pipe.

[0049] To discharge the sludge after hydrolysis and acidification, the hydrolysis and acidification reactor 1 of this embodiment also includes a sludge discharge system 18. This sludge discharge system 18 is located at the bottom of the hydrolysis and acidification reaction tank 14. The sludge at the bottom of the hydrolysis and acidification reaction tank 14 is discharged through the sludge discharge system 18. Preferably, the sludge discharge system 18 includes a sludge discharge pipe and a sludge discharge pump, which are connected to the sludge discharge pipe and the sludge discharge pump. The sludge inlet of the sludge discharge pipe is located above the water distribution system 162. The sludge discharge system 18 controls the sludge concentration and sludge production within the hydrolysis and acidification reactor by periodically discharging a portion of the sludge, thereby controlling the sludge age.

[0050] In one embodiment, the water inlet system 15 of the primary hydrolysis and acidification reactor 11 receives pretreated raw water for hydrolysis and acidification reaction. The hydraulic retention time of the primary hydrolysis and acidification reactor 11 is ≥6 hours, and the sludge age is 30 to 50 days.

[0051] The water inlet system 15 of the secondary hydrolysis acidification reactor 12 receives pretreated raw water or effluent from the primary hydrolysis acidification reactor 11. The hydraulic retention time of the secondary hydrolysis acidification reactor 12 is ≥8h, and the sludge age is ≥40 days.

[0052] The water inlet system 15 of the tertiary hydrolysis and acidification reactor 13 receives the effluent from the secondary hydrolysis and acidification reactor. The hydraulic retention time of the tertiary hydrolysis and acidification reactor 13 is ≥8h, and the sludge age is ≥40 days.

[0053] The redox potential in the primary hydrolysis acidification reactor 11, the secondary hydrolysis acidification reactor 12 and the tertiary hydrolysis acidification reactor 13 is controlled within a range of -450 mv to -200 mv.

[0054] To achieve the electrocatalytic reaction of wastewater, the first-stage electrocatalytic reactor 21, the second-stage electrocatalytic reactor 22, and the third-stage electrocatalytic reactor 23 each include an electrocatalytic reaction cell body 24. The electrocatalytic reaction cell body 24 has interconnected electrode water inlet area, electrode water outlet area, and electrode area, with the electrode area located between the electrode water inlet area and the electrode water outlet area.

[0055] The primary electrocatalytic reactor 21, the secondary electrocatalytic reactor 22, and the tertiary electrocatalytic reactor 23 also include electrode assemblies 25, a power supply system 26, and an aeration system 27. The electrode assemblies 25 are evenly distributed in the electrode area. The power supply system 26 includes a junction box and a regulated power supply. The regulated power supply is connected to the electrode assemblies 25 via the junction box, and the regulated power supply provides a stable low-voltage power supply to the electrode assemblies 25. The regulated power supply and junction box are located outside the electrocatalytic cell body. The electrode assemblies 25 are connected to the junction box via electrode wires, and the junction box is connected to the regulated power supply via metal wires. The electrode wires are carbon fiber wires, and the metal wires are copper wires.

[0056] like Figure 2 As shown, the electrode assembly 25 includes an anode electrode plate 251 and a cathode electrode plate 252 that are spaced apart. The anode electrode plate 251 and the cathode electrode plate 252 are both fixed to an electrode bracket 253. The electrode bracket 253 is made of PP material or stainless steel anti-corrosion material, and is used to provide positioning and support for the anode electrode plate 251 and the cathode electrode plate 252. The electrode bracket 253 is fixed in the electrocatalytic reaction cell body 24, with 2 to 10 cm reserved on both sides from the edge of the cell body, and the electrode bracket 253 is 5 to 30 cm higher than the liquid level. Two adjacent electrode plates, one positive and one negative, form an electrode pair, and multiple electrode pairs form an electrode group. The distance between adjacent electrode plates is 5-30 cm.

[0057] Electrocatalytic fillers 254 are provided on both the anode electrode plate 251 and the cathode electrode plate 252. The electrocatalytic fillers 254 are spaced apart along the height direction of the anode electrode plate 251 and the cathode electrode plate 252. The spacing between adjacent electrocatalytic fillers 254 on the same electrode plate is 6-20 cm.

[0058] In one embodiment, the electrocatalytic filler 254 is woven from modified carbon fibers and nylon. Preferably, the redirected carbon fibers are woven into a bio-rope filler with excellent electrical conductivity and microbial attachment capacity, enabling microbial enrichment. The bio-rope filler also removes, breaks, and loops pollutants under the action of a low-voltage electric field provided by the power supply system 26. The modified carbon fibers are conventionally modified carbon fibers. Compared to electrodes made of materials such as metal and graphite sheets, the electrocatalytic filler 254 woven from carbon fibers significantly reduces the amount of carbon material used while also ensuring the filler's strength, making it less susceptible to breakage and fracture, thereby reducing investment costs. Furthermore, the braided carbon fiber material, due to its high volume and high fiber count, possesses an excellent specific surface area, and the presence of a nylon wire skeleton allows for the attachment of more microorganisms. The electrocatalytic filler 254 composed of modified carbon fibers has low electrical resistance. Combined with the carbon fibers' high specific surface area, the modified carbon fibers effectively transfer more electrons, promoting electron transfer in microbial reactions and accelerating the decomposition, loop opening, and degradation of organic matter. This effectively improves the removal efficiency of biotreatment technologies for indicators such as COD.

[0059] In one embodiment, the voltage between the anode electrode plate 251 and the cathode electrode plate 252 ranges from 0.1 to 2.5 V, and the current ranges from 0.001 to 0.02 A. The voltage regulator needs to regulate the voltage during the operation of the multi-stage hydrolysis-acidification coupled electrocatalytic device according to the microbial enrichment. The voltage is regulated at 0.1 to 0.5 V in the early stage of operation, 0.5 to 1.5 V in the middle stage of operation, and 1.5 to 2.5 V in the late stage of operation.

[0060] One end of the copper wire is connected to a voltage-stabilized power supply, and the other end is connected to a terminal in a junction box or an air switch. The other end of the terminal in the junction box or the air switch is connected to a carbon fiber wire, and the other end of the carbon fiber wire is directly connected and fixed to the electrode filler in the electrode plate.

[0061] like Figure 3 As shown, the aeration system 27 is disposed at the bottom of the electrocatalytic reaction cell 24 and includes a blower 271, an air intake main pipe 272, multiple air intake branches 273, and multiple microporous aeration pipes 274. The air outlet of the blower 271 is connected to the air inlet of the air intake main pipe 272, the multiple air intake branches 273 are respectively connected to the air intake main pipe 272, and the multiple microporous aeration pipes 274 are respectively connected to the air outlets of the multiple air intake branches 273. Each of the multiple air intake branches 273 is provided with a ball valve 275.

[0062] The electrode outlet area and the electrode inlet area are both equipped with an ORP detector 28 and a pH probe 29. The ORP detector 28 and the pH probe 29 monitor the operating status of the electrocatalytic reactor 2, and the aeration volume of the aeration system 27 can be adjusted according to the detected ORP value to provide a micro-oxygen environment for the hydrolysis and acidification reaction. When the ORP value is higher than -200mV, the aeration is turned off, and when the ORP value is lower than -200mV, the aeration is turned on. When the ORP value is lower than -450mV, the valve is regulated to increase the aeration volume, and the aeration system 27 is adjusted according to the ORP value fed back by the ORP detector 28, so that the sewage in the electrocatalytic reactor 2 is in an oxygenated condition. The sewage under the oxygenated condition is returned to the adjustable water distributor 160 through the reflux system 4, and then evenly distributed to the bottom of the hydrolysis and acidification reactor 1, which can provide a micro-oxygen environment for the hydrolysis and acidification reaction. In addition, the aeration system 27 can also be used to aerate and stir the sludge at the bottom of the electrocatalytic reactor 1 and return it to the hydrolysis and acidification reactor 1 through the reflux pump 43.

[0063] In one embodiment, the hydraulic retention time in the electrocatalytic reaction cell body 24 is 0.2 to 3 hours, and the hydraulic retention time in the electrode water inlet area is 5 to 45 minutes.

[0064] When the multi-stage hydrolysis-acidification coupled electrocatalytic device of this embodiment is in use, the pretreated raw water first enters the hydrolysis-acidification reaction tank body 14 of the first hydrolysis-acidification reactor 11, where the first hydrolysis-acidification reaction is carried out. Simultaneously, the sewage in the hydrolysis-acidification reaction tank body 14 flows into the first electrocatalytic reactor 21 through the reflux system 4. The sewage entering the first electrocatalytic reactor 21 briefly stays in the electrode area, where microorganisms in the sewage are attached to the electrocatalytic filler 254, and the dominant hydrolysis-acidification bacteria are continuously enriched on the electrocatalytic filler 254. Simultaneously, the power supply system 26 can provide a stable low-voltage electric field for the electrode assembly 25. Under the action of the low-voltage electric field, the electron transfer between the microorganisms attached to the electrocatalytic filler 254 is promoted, thereby accelerating the degradation of pollutants by the microorganisms and promoting the hydrolysis-acidification reaction.

[0065] The wastewater treated in the primary hydrolysis and acidification reactor 11 enters the secondary hydrolysis and acidification reactor 12 and the secondary electrocatalytic reactor 22, and is further hydrolyzed and acidified in the secondary hydrolysis and acidification reactor 12. The wastewater treated in the secondary hydrolysis and acidification reactor 12 enters the tertiary hydrolysis and acidification reactor 13 and the tertiary electrocatalytic reactor 23, and is further hydrolyzed and acidified in the tertiary hydrolysis and acidification reactor 13.

[0066] During the primary hydrolysis and acidification stage, microorganisms break down recalcitrant macromolecules in the raw water into small organic molecules, such as proteins into amino acids and starch into carbohydrates. In the secondary hydrolysis and acidification stage, microorganisms continue to break down recalcitrant macromolecules that remained unbroken during the primary hydrolysis and acidification stage into small organic molecules. Simultaneously, the products of the primary hydrolysis and acidification are broken down into readily degradable small organic molecules, such as amino acids into VFAs and carbohydrates into alcohols. In the tertiary hydrolysis and acidification stage, microorganisms continue to break down recalcitrant macromolecules that remained unbroken during the secondary hydrolysis and acidification stage into small organic molecules. Simultaneously, the products of the secondary hydrolysis and acidification are further broken down into readily degradable small organic molecules and stable organic products such as methane and carbon dioxide. Through the tertiary hydrolysis and acidification stages, the macromolecules in the raw water are broken down step by step, reducing the COD content and improving the biodegradability of the wastewater.

[0067] Refer to the table below, which shows the effluent indicators after three-stage hydrolysis and acidification coupled electrocatalytic treatment:

[0068]

[0069]

[0070] like Figure 4 As shown, Figure 4 The following chart compares COD removal rates after hydrolysis and acidification. After hydrolysis and acidification, the average COD removal rate for primary hydrolysis and acidification was 25%, while that for tertiary hydrolysis and acidification was 48%, a 23% improvement over primary hydrolysis and acidification. The average COD removal rate for tertiary hydrolysis and acidification coupled with electrocatalysis was 61%, a 36% and 13% improvement over primary and tertiary hydrolysis and acidification, respectively.

[0071] This embodiment improves the population abundance of microorganisms through three-stage hydrolysis and acidification, and enhances the efficiency of chain-breaking decomposition of macromolecular organic matter in industrial wastewater. In addition, the multi-stage series connection method reduces the impact caused by shock load and ensures the stable operation of the multi-stage hydrolysis and acidification coupled electrocatalytic device. Through the electrocatalytic reactor, under the action of an external low-voltage electric field and a micro-oxygen environment, it is beneficial to the growth and activity of hydrolysis and acidification dominant microorganisms, promotes electron transfer between microorganisms, accelerates the hydrolysis and acidification reaction, and reduces the generation of toxic or difficult-to-degrade compounds in industrial wastewater. The multi-stage hydrolysis and acidification coupled electrocatalytic device of this embodiment has the characteristics of high efficiency of pollutant chain-breaking decomposition, stable operation, and simple structure.

[0072] In one embodiment, after pretreated raw water is directly connected to the water inlet system 15 of the secondary hydrolysis and acidification reactor 12, the pretreated raw water directly enters the secondary hydrolysis and acidification reactor 12 for acidification. The sewage in the secondary hydrolysis and acidification reactor 12 then enters the secondary electrocatalytic reactor 22 via the reflux system 4. The sewage entering the secondary electrocatalytic reactor 22 briefly resides in the electrode zone, where microorganisms in the sewage attach to the electrocatalytic filler 254, and the dominant hydrolysis and acidification bacteria continuously accumulate on the electrocatalytic filler 254. Simultaneously, the power supply system 26 can provide a stable low-voltage electric field for the electrode assembly 25. This low-voltage electric field promotes electron transfer between the microorganisms attached to the electrocatalytic filler 254, accelerating the degradation of pollutants by the microorganisms and promoting the hydrolysis and acidification reaction.

[0073] The wastewater after the primary hydrolysis and acidification reaction in the secondary hydrolysis and acidification reactor 12 enters the tertiary hydrolysis and acidification reactor 13. The wastewater in the tertiary hydrolysis and acidification reactor 13 enters the tertiary electrocatalytic reactor 23 through the reflux system 4 for electrocatalysis. The wastewater after the secondary hydrolysis in the tertiary hydrolysis and acidification reactor 13 is discharged.

[0074] Specifically, when the COD concentration in the pretreated raw water is ≤1000 mg / L, the pretreated raw water bypasses the inlet system 15 of the primary hydrolysis and acidification reactor 11 and directly enters the inlet system 15 of the secondary hydrolysis and acidification reactor 12. Furthermore, the hydraulic retention time (HRT) of the secondary hydrolysis and acidification reactor 12 is ≥6 hours, and the sludge age is 30 to 50 days; the HRT of the tertiary hydrolysis and acidification reactor 13 is ≥8 hours, and the sludge age is ≥40 days. The redox potentials of the secondary and tertiary hydrolysis and acidification reactors 12 and 13 are controlled between -450 mV and -200 mV.

[0075] Example 2

[0076] This embodiment discloses a hydrolysis and acidification method, comprising the following steps:

[0077] The pretreated sewage enters the primary hydrolysis and acidification reactor 11 for hydrolysis and acidification reaction;

[0078] The sewage in the primary hydrolysis acidification reactor 11 enters the corresponding primary electrocatalytic reactor 21 through the reflux system 4 to undergo electrocatalytic reaction;

[0079] The sewage in the primary electrocatalytic reactor 21 enters the primary hydrolysis and acidification reactor 11 again through the reflux system 4 for hydrolysis and acidification;

[0080] The wastewater after primary hydrolysis and acidification in the primary hydrolysis and acidification reactor 11 enters the secondary hydrolysis and acidification reactor 12 for hydrolysis and acidification reaction;

[0081] The wastewater in the secondary hydrolysis acidification reactor 12 enters the corresponding secondary electrocatalytic reactor 22 through the reflux system 4 to undergo electrocatalytic reaction;

[0082] The wastewater in the secondary electrocatalytic reactor 22 enters the secondary hydrolysis and acidification reactor 12 again through the reflux system 4 for hydrolysis and acidification;

[0083] The wastewater after the secondary hydrolysis and acidification in the secondary hydrolysis and acidification reactor 12 enters the tertiary hydrolysis and acidification reactor 13 for hydrolysis and acidification reaction;

[0084] The sewage in the tertiary hydrolysis acidification reactor 13 enters the corresponding tertiary electrocatalytic reactor 23 through the reflux system 4 to undergo electrocatalytic reaction;

[0085] The sewage in the three-stage electrocatalytic reactor 23 enters the three-stage hydrolysis and acidification reactor 13 again through the reflux system 4 for hydrolysis and acidification.

[0086] This embodiment improves the population abundance of microorganisms and the efficiency of pollutant chain decomposition by performing a tertiary hydrolysis and acidification reaction on sewage. At the same time, it promotes the electron transfer between microorganisms, thereby promoting the hydrolysis and acidification reaction and improving the biodegradability of sewage.

[0087] In the description of this specification, the reference terms "one embodiment," "some embodiments," "example," "specific example," or "some examples" mean that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. Moreover, the specific features, structures, materials, or characteristics described may be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification, as well as features of different embodiments or examples, unless they are mutually inconsistent.

[0088] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0089] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any person skilled in the art can easily conceive of various modifications or substitutions within the technical scope disclosed in this application, and such modifications or substitutions should be included within the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A multi-stage hydrolysis-acidification coupled electrocatalytic device, characterized in that: include: Multi-stage hydrolysis acidification reactor, the pretreated raw water is connected to the water inlet of the first and / or second hydrolysis acidification reactor through a water pipe, and the water inlet of the next hydrolysis acidification reactor is connected to the water outlet of the previous hydrolysis acidification reactor; Multi-stage electrocatalytic reactor, multi-stage hydrolysis acidification reactor is connected to the corresponding electrocatalytic reactor through a reflux system, the electrocatalytic reactor has an electrode area, the sewage in the hydrolysis acidification reactor passes through the electrode area in the electrocatalytic reactor and returns to the corresponding hydrolysis acidification reactor; The electrocatalytic reactor includes an electrocatalytic reaction cell body and an electrode assembly. The electrocatalytic reaction cell body also has an electrode water inlet area and an electrode water outlet area. The electrode area is located between the electrode water inlet area and the electrode water outlet area, and the electrode assembly is placed in the electrode area. The electrode assembly comprises an anode electrode plate and a cathode electrode plate which are arranged at intervals. Both the anode electrode plate and the cathode electrode plate are provided with electrocatalytic fillers which are made of modified carbon fiber and nylon material.

2. The multi-stage hydrolysis-acidification coupled electrocatalytic device according to claim 1, characterized in that: The hydrolysis and acidification reactor includes a hydrolysis and acidification reaction tank body, a water inlet system, a water distribution system and a water outlet system. The water inlet of the water inlet system is connected to the water pipe, and / or the water inlet of the water inlet system is connected to the water outlet of the water outlet system of the previous hydrolysis and acidification reactor. The water distribution system is fixed in the hydrolysis and acidification reaction tank body, and the water outlet of the water inlet system is connected to the water distribution system. The sewage in the electrocatalytic reactor is returned to the water distribution system through the reflux system.

3. The multi-stage hydrolysis-acidification coupled electrocatalytic device according to claim 2, characterized in that: The water distribution system includes an adjustable water distributor, a central vertical shaft and a water distribution system. The central vertical shaft is located in the hydrolysis and acidification reaction tank. The top of the central vertical shaft is connected to the adjustable water distributor, the bottom of the central vertical shaft is connected to the water distribution system, and the outlet of the water inlet system is connected to the interior of the central vertical shaft.

4. The multi-stage hydrolysis-acidification coupled electrocatalytic device according to claim 3, characterized in that: The reflux system includes a first reflux pipeline, a second reflux pipeline and a reflux pump. The reflux inlet of the first reflux pipeline is located in the hydrolysis and acidification reaction tank body, the reflux outlet of the first reflux pipeline is connected to the interior of the electrocatalytic reactor, the reflux inlet of the second reflux pipeline is connected to the interior of the electrocatalytic reactor, the reflux pump is connected to the second reflux pipeline, and the reflux pump returns the sewage in the electrocatalytic reactor to the adjustable water distributor through the second reflux pipeline.

5. The multi-stage hydrolysis-acidification coupled electrocatalytic device according to claim 2, characterized in that: The hydrolysis acidification reactor also includes a sludge discharge system, which is placed at the bottom of the hydrolysis acidification reaction tank body. The sludge at the bottom of the hydrolysis acidification reaction tank body is discharged through the sludge discharge system; the effluent system is located at the top inner side of the hydrolysis acidification reaction tank body. The treated sewage in the hydrolysis acidification reaction tank body is discharged through the effluent system.

6. The multi-stage hydrolysis-acidification coupled electrocatalytic device according to claim 1, characterized in that: The electrocatalytic reactor also includes a power supply system, which includes a junction box and a voltage-stabilized power supply. The voltage-stabilized power supply is connected to the electrode assembly through the junction box, and the voltage-stabilized power supply provides a stable low-voltage power supply for the electrode assembly.

7. The multi-stage hydrolysis-acidification coupled electrocatalytic device according to claim 6, characterized in that: The electrocatalytic reactor also includes an aeration system, which includes a blower, an air intake main pipe, multiple air intake branches and multiple microporous aeration pipes. The air outlet of the blower is connected to the air intake of the air intake main pipe, the multiple air intake branches are respectively connected to the air intake main pipe, the multiple microporous aeration pipes are respectively connected to the air outlets of the multiple air intake branches, and the multiple air intake branches are all provided with ball valves; the electrode water outlet area and the electrode water inlet area are both provided with ORP detectors and pH probes.

8. A hydrolysis and acidification method, characterized in that: The following steps are involved: The pretreated sewage enters the primary hydrolysis and acidification reactor for hydrolysis and acidification reaction; The sewage in the primary hydrolysis acidification reactor enters the corresponding primary electrocatalytic reactor through the reflux system to undergo electrocatalytic reaction; The sewage in the primary electrocatalytic reactor enters the primary hydrolysis and acidification reactor again through the reflux system for hydrolysis and acidification; The wastewater after primary hydrolysis in the primary hydrolysis acidification reactor enters the secondary hydrolysis acidification reactor for hydrolysis and acidification reaction; The wastewater in the secondary hydrolysis acidification reactor enters the corresponding secondary electrocatalytic reactor through the reflux system for electrocatalytic reaction; The sewage in the secondary electrocatalytic reactor enters the secondary hydrolysis and acidification reactor again through the reflux system for hydrolysis and acidification; The wastewater after secondary hydrolysis in the secondary hydrolysis acidification reactor enters the tertiary hydrolysis acidification reactor for hydrolysis and acidification reaction; The sewage in the three-stage hydrolysis acidification reactor enters the corresponding three-stage electrocatalytic reactor through the reflux system to carry out electrocatalytic reaction; The sewage in the three-stage electrocatalytic reactor enters the three-stage hydrolysis acidification reactor again through the reflux system for hydrolysis and acidification, completing the three-stage hydrolysis and acidification.

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