Efficient energy-saving anti-blocking nanobubble aeration process based on silicon carbide ceramic membrane

Abstract

The invention relates to the technical field of sewage treatment, in particular to an efficient energy-saving anti-blocking nanobubble aeration process based on a silicon carbide ceramic membrane, which is used for completing the installation and debugging work of a micro-nanobubble aeration device. Devices used during installation comprise an oxygen generation device, a filtering device, a gas flow control device, an ozone generation device, a concentration detection device, micro-nano bubble generation equipment, a backwashing device, a pressure detection device, a controller, a reaction device and an ozone tail gas treatment device. The nanobubble aeration process can ensure that nanobubbles can be stably and efficiently generated, the oxygen transfer efficiency is improved, the treatment effect is improved, the sewage treatment cost is effectively reduced, micro-nano ozone bubbles are combined with a nano flocculant, impurities such as suspended particles and colloidal substances in wastewater are effectively removed, and the treatment effect is improved. Meanwhile, through comprehensive application of various anti-blocking measures, the problem that a membrane material is easy to block in a traditional aeration process is effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and particularly relates to an energy-efficient and anti-clogging nano-bubble aeration process based on silicon carbide ceramic membranes. Background Art

[0002] In the process of sewage treatment, aeration is one of the key links. Its purpose is to provide sufficient dissolved oxygen to the sewage to meet the needs of microorganisms to decompose organic matter. The nano-bubble aeration technology has received extensive attention because it can generate tiny bubbles, increase the gas-liquid contact area, and improve the oxygen transfer efficiency.

[0003] In traditional nano-bubble aeration processes, when treating sewage with a nano-bubble generator, pollutants such as suspended particles and colloidal substances in the sewage enter the nano-bubble generator and adhere to the surface of the membrane material, resulting in membrane clogging. This cannot ensure the stable and efficient generation of nano-bubbles, reducing the oxygen transfer efficiency of the aeration process. Therefore, when treating sewage, traditional nano-bubble aeration processes still face problems such as easy clogging of membrane materials, low sewage treatment efficiency, and short service life, which limit their large-scale popularization and application.

[0004] In summary, developing an energy-efficient and anti-clogging nano-bubble aeration process based on silicon carbide ceramic membranes remains a key problem urgently to be solved in the technical field of sewage treatment. Summary of the Invention

[0005] Aiming at the problems existing in the prior art, the purpose of the present invention is to provide an energy-efficient and anti-clogging nano-bubble aeration process based on silicon carbide ceramic membranes.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] An energy-efficient and anti-clogging nano-bubble aeration process based on silicon carbide ceramic membranes, comprising the following steps:

[0008] S1. Complete the installation and commissioning of the micro-nano bubble aeration device, and the devices used in the installation include an oxygen generation device, a filtration device, a gas flow control device, an ozone generation device, a concentration detection device, a micro-nano bubble generation device, a backwashing device, a pressure detection device, a controller, a reaction device, and an ozone tail gas treatment device;

[0009] S2. Take a certain amount of wastewater and put it into the reaction device, and continuously circulate and aerate the wastewater through the micro-nano bubble aeration device for 3 - 6 hours;

[0010] S3. According to the wastewater volume, add a certain amount of nano-flocculant and polymer flocculant PAM into the reaction device, stir for 30 - 60 s under the condition of 200 - 300 r / min by a magnetic stirrer, and let it stand for 10 - 30 min after mixing evenly;

[0011] S4. Wait for the solution in the reaction device to precipitate and stratify, take the supernatant, analyze it on a multi-parameter colorimeter, measure the COD of the wastewater and the supernatant according to the corresponding procedure, and calculate the COD removal rate;

[0012] S5. When the running time of the micro-nano bubble generating device reaches 3 h or the pressure difference across the silicon carbide ceramic membrane of the micro-nano bubble generating device exceeds 0.2 MPa, the backwashing device automatically backwashes the micro-nano bubble generating device, and at the same time, regularly add a certain amount of chemical agent into the reaction device to prevent pollutants from depositing on the surface of the silicon carbide ceramic membrane in the micro-nano bubble generating device.

[0013] The present invention is further configured as: in step S1, the installation and commissioning work of the micro-nano bubble aeration device includes the following steps:

[0014] S11. Install pressure detection devices on both sides of the silicon carbide ceramic membrane in the micro-nano bubble generating device, and install the backwashing device with the micro-nano bubble generating device;

[0015] S12. Install the micro-nano bubble generating device in the reaction device according to the design requirements, then connect the ozone tail gas treatment device with the reaction device, connect the pipelines between the oxygen generating device, the filtering device, the gas flow control device, the ozone generating device, the concentration detection device and the micro-nano bubble generating device, and check whether the pipeline connections are tight and there is no leakage;

[0016] S13. Connect the controller with the above-mentioned devices to obtain the micro-nano bubble aeration device, and commission the micro-nano bubble aeration device. Adjust the gas flow through the gas flow control device to meet the design requirements, and at the same time, check whether the micro-nano bubble generating device is working properly and observe whether bubbles are evenly released from the membrane surface.

[0017] The present invention is further configured as: in step S2, continuously circulate and aerate the wastewater through the micro-nano bubble aeration device, including the following steps:

[0018] S21. Start the micro-nano bubble aeration device, the filtering device filters the oxygen in the oxygen generating device, and the filtered oxygen enters the ozone generating device through the gas flow control device to generate ozone;

[0019] S22. Adjust the ozone gas flow to 0.3 - 0.6 L / min, and detect the ozone concentration to reach 150 - 180 mg / L through the concentration detection device;

[0020]

[0020] After the concentration of the ozone gas stabilizes, start the micro-nano bubble generating device. The ozone gas enters the interior of the micro-nano bubble generating device through a pipeline. By virtue of the uniform and controllable micropores of the silicon carbide ceramic membrane, the ozone gas is dispersed into ozone micro-nano bubbles. After the ozone micro-nano bubbles are released from the membrane surface, they enter the wastewater in the reaction device and undergo an oxidation reaction with the organic matter in the wastewater.

[0021]

[0021] S24. While the reaction is taking place, turn on the ozone tail gas treatment device to treat the tail gas generated by the reaction.

[0022]

[0022] The present invention is further configured such that: in step S3, according to the amount of wastewater, the input amount of the nano flocculant is 2 - 4 g / L, and the input amount of the polymer flocculant PAM is 1 - 3 g / L.

[0023]

[0023] The present invention is further configured such that: in step S3, the preparation method of the nano flocculant includes the following steps:

[0024] S31. Prepare nano nickel oxide and perform modification treatment to obtain vinyl-modified nano nickel oxide;

[0025]

[0025] S32. By mass, add 2 - 5 parts of vinyl-modified nano nickel oxide, 5 - 11 parts of acrylamide, 10 - 16 parts of dimethyldiallylammonium chloride, 5 - 7 parts of activated carbon, and 1 - 4 parts of cerium nitrate to 20 - 37 parts of deionized water. After fully stirring and dissolving, prepare a monomer mixed solution with a certain concentration, and lower the temperature of the monomer mixed solution to 0 - 3 °C;

[0026]

[0026] S33. Weigh 1 - 3 parts of ammonium persulfate and 2 - 5 parts of sodium bisulfite by mass respectively, and dissolve them in 5 - 12 parts of deionized water to prepare an initiator solution with a certain concentration;

[0027]

[0027] S34. Introduce nitrogen into the polymerization kettle for 20 - 30 min to remove the oxygen in the system;

[0028]

[0028] S35. Transfer the prepared monomer solution into the polymerization kettle and introduce nitrogen at a flow rate of 65 m 3 / h for 1 - 1.5 h, then add the initiator solution to initiate the polymerization reaction, and the polymerization reaction lasts for 4 - 5 h;

[0029]

[0029] S36. After the reaction ends, pour the reaction solution into a large amount of absolute ethanol to precipitate the polymer. The volume ratio of absolute ethanol to the reaction solution is 2 - 3:1. Stir to make the precipitation more complete and let it stand for 10 - 25 min;

[0030]

[0030] S37. Filter out the precipitate, wash it with absolute ethanol multiple times to remove the unreacted impurities. After each washing, perform suction filtration until no impurities are detected in the washing liquid;

[0031] S38. Place the washed product in a vacuum drying oven and dry it at a temperature of 30 - 40 °C for 2 - 3 h to obtain a dried nano flocculant.

[0032] The present invention is further configured as follows: In step S31, prepare nano nickel oxide and carry out modification treatment to obtain vinyl-modified nano nickel oxide, including the following steps:

[0033] S311. Dissolve 2 - 3 parts of nickel acetate tetrahydrate in 110 - 130 parts of deionized water by mass. While stirring, gradually add ammonia water dropwise to adjust the pH to 9.7 - 10, and continue stirring until nickel hydroxide sol is formed.

[0034] S312. Transfer the nickel hydroxide sol into a reaction kettle and keep it in a furnace at 400 °C for 4 - 6 h. Then, filter the product by suction, and wash it with deionized water and absolute ethanol until it is neutral. After vacuum drying at 60 °C for 24 h, nano nickel oxide is obtained.

[0035] S313. Dropwise add a vinyl silane coupling agent to the surface of nano nickel oxide. After stirring evenly, add acrylic acid. The mass ratio of the vinyl silane coupling agent, nano nickel oxide, and acrylic acid is 2 - 4:25:3 - 5, and stir and react for 1 - 2 h to obtain vinyl-modified nano nickel oxide.

[0036] The present invention is further configured as follows: In step S5, the backwashing device automatically backwashes the micro-nano bubble generating device, including the following steps:

[0037] S51. When the running time of the micro-nano bubble generating device reaches 3 h or the pressure difference across the silicon carbide ceramic membrane exceeds 0.2 MPa, the controller automatically shuts down the oxygen generating device and emits a prompt sound through a promptor.

[0038] S52. The controller automatically opens the valve of the backwashing device, so that high-pressure gas or liquid reversely passes through the silicon carbide ceramic membrane of the micro-nano bubble generating device at a specific pressure and flow rate, and automatically backwashes the micro-nano bubble generating device.

[0039] S53. Continuously backwash for 15 - 30 min. During the process, judge the backwashing effect by observing the water quality of the backwashing drainage. When the drainage is clear and there are no obvious impurities, close the backwashing device through the controller.

[0040] The present invention is further configured as follows: In step S5, the chemical agents are a dispersant and a cleaning agent. The addition amount of the dispersant is 10 - 20 mg / L, and the addition amount of the cleaning agent is 4 - 10 mg / L.

[0041] Beneficial effects

[0042] Adopting the technical solution provided by the present invention, compared with the known public technology, it has the following

[0043] Beneficial effects:

[0044] (1) In the present invention, by adding a nano-flocculant to the wastewater, the nano-bubble aeration process combines micro-nano ozone bubbles with the nano-flocculant. The nano-flocculant can effectively remove impurities such as suspended particles and colloidal substances in the wastewater during wastewater treatment. After the wastewater is subjected to good flocculation precipitation treatment and enters the aeration process of the silicon carbide ceramic membrane, the probability of pollutant attachment on the membrane surface can be reduced, and the risk of membrane blockage can be lowered, thereby ensuring that nano-bubbles can be stably and efficiently generated and maintaining the oxygen transfer efficiency of the aeration process. At the same time, the nano-bubbles generated by the silicon carbide ceramic membrane in the micro-nano bubble generating device can greatly increase the gas-liquid contact area and improve the oxygen transfer efficiency, thus accelerating the sewage treatment speed and improving the treatment effect. Compared with the traditional aeration process, the aeration process of the present invention has reduced energy consumption and can effectively reduce the sewage treatment cost.

[0045] (2) In the present invention, by adding a filtering device after the oxygen generating device, the gas passing through the micro-nano bubble generating device can be filtered to reduce the impurities in the gas. At the same time, the micro-nano bubble generating device is improved by adding a pressure detection device and a backwashing device. When the operation time of the micro-nano bubble generating device reaches 3 h or the pressure difference across the silicon carbide ceramic membrane exceeds 0.2 MPa, the backwashing device automatically backwashes the micro-nano bubble generating device. In addition, a certain amount of chemical agent is regularly added to the reaction device to prevent pollutants from depositing on the surface of the silicon carbide ceramic membrane in the micro-nano bubble generating device. Through the comprehensive application of various anti-blocking measures, the nano-bubble aeration process of the present invention effectively solves the problem of easy blockage of the membrane material in the traditional aeration process, extends the service life of the membrane module, and reduces the equipment maintenance cost. Description of the drawings

[0046] Figure 1 It is a process flow diagram of a high-efficiency, energy-saving and anti-blocking nano-bubble aeration process based on a silicon carbide ceramic membrane. Detailed implementation manners

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0048] The following further describes the present invention with reference to the embodiments.

[0049] Example 1: Please refer to Figure 1As shown in the figure, an energy-efficient and anti-clogging nano-bubble aeration process based on a silicon carbide ceramic membrane includes the following steps:

[0050] S1. Install and commission the micro-nano bubble aeration device;

[0051] S2. Take a certain amount of wastewater and put it into the reaction device, and continuously circulate and aerate the wastewater through the micro-nano bubble aeration device for 3 hours, including the following steps:

[0052] S21. Start the micro-nano bubble aeration device, and the filtration device filters the oxygen in the oxygen generation device. The filtered oxygen enters the ozone generation device through the gas flow control device to generate ozone;

[0053] S22. Adjust the ozone gas flow to 0.3 L / min, and detect the ozone concentration through the concentration detection device to reach 150 mg / L;

[0054] S23. After the ozone gas concentration is stable, start the micro-nano bubble generation device. The ozone gas enters the inside of the micro-nano bubble generation device through the pipeline. Relying on the uniform and controllable micropores of the silicon carbide ceramic membrane, the ozone gas is dispersed into ozone micro-nano bubbles. After the ozone micro-nano bubbles are released from the membrane surface, they enter the wastewater in the reaction device and react with the organic matter in the wastewater;

[0055] S24. While the reaction is in progress, turn on the ozone tail gas treatment device to treat the tail gas generated by the reaction;

[0056] S3. According to the amount of wastewater, add a certain amount of nano-flocculant and polymer flocculant PAM to the reaction device, stir for 30 s under the condition of 200 r / min by a magnetic stirrer, mix evenly and then stand for 10 min;

[0057] Among them, the input amount of the nano-flocculant is 2 g / L, and the input amount of the polymer flocculant PAM is 1 g / L;

[0058] Among them, the preparation method of the nano-flocculant includes the following steps:

[0059] S31. Prepare nano-nickel oxide and carry out modification treatment to obtain vinyl-modified nano-nickel oxide, including the following steps:

[0060] S311. Dissolve 2 parts of nickel acetate tetrahydrate in 110 parts of deionized water by mass, dropwise add ammonia water while stirring to adjust the pH to 9.7, and continue stirring until nickel hydroxide sol is formed;

[0061] S312. Transfer the nickel hydroxide sol into a reaction kettle and keep it in a furnace at 400 °C for 4 h. Then, filter the product by suction, wash it with deionized water and absolute ethanol until it is neutral, and dry it in vacuum at 60 °C for 24 h to obtain nano-nickel oxide;

[0062] S313. Drop the vinyl silane coupling agent onto the surface of nano nickel oxide. After stirring evenly, add acrylic acid. The mass ratio of the vinyl silane coupling agent, nano nickel oxide, and acrylic acid is 2:25:3. Stir and react for 1 h to obtain vinyl-modified nano nickel oxide.

[0063] S32. Add 2 parts of vinyl-modified nano nickel oxide, 5 parts of acrylamide, 10 parts of dimethyldiallylammonium chloride, 5 parts of activated carbon, and 1 part of cerium nitrate by mass to 20 parts of deionized water. After fully stirring and dissolving, prepare a monomer mixed solution with a certain concentration. Cool the temperature of the monomer mixed solution to 0 °C.

[0064] S33. Weigh 1 part of ammonium persulfate and 2 parts of sodium bisulfite by mass respectively, and dissolve them in 5 parts of deionized water to prepare an initiator solution with a certain concentration.

[0065] S34. Introduce nitrogen into the polymerization kettle for 20 min to remove oxygen in the system.

[0066] S35. Transfer the prepared monomer solution into the polymerization kettle and introduce nitrogen at a flow rate of 65 m 3 / h for 1 h, then add the initiator solution to initiate the polymerization reaction, and the polymerization reaction lasts for 4 h.

[0067] S36. After the reaction is completed, pour the reaction solution into a large amount of absolute ethanol to precipitate the polymer. The volume ratio of absolute ethanol to the reaction solution is 2:1. Stir to make the precipitation more complete and let it stand for 10 min.

[0068] S37. Filter out the precipitate, wash it with absolute ethanol multiple times to remove unreacted impurities. Perform suction filtration after each washing until no impurities are detected in the washing liquid.

[0069] S38. Place the washed product in a vacuum drying oven and dry it at 30 °C for 2 h to obtain a dried nano flocculant.

[0070] S4. Wait for the solution in the reaction device to precipitate and stratify, and take the supernatant.

[0071] S5. When the operation time of the micro-nano bubble generating device reaches 3 h or the pressure difference across the silicon carbide ceramic membrane exceeds 0.2 MPa, the backwashing device automatically backwashes the micro-nano bubble generating device for 15 min. At the same time, regularly add a certain amount of chemical agents to the reaction device to prevent pollutants from depositing on the surface of the silicon carbide ceramic membrane in the micro-nano bubble generating device.

[0072] Among them, the chemical agents are a dispersant and a cleaning agent. The addition amount of the dispersant is 10 mg / L, and the addition amount of the cleaning agent is 4 mg / L.

[0073] Example 2: Please refer to Figure 1 As shown in the figure, a high-efficiency energy-saving and anti-blocking nano-bubble aeration process based on a silicon carbide ceramic membrane includes the following steps:

[0074] S1. Complete the installation and commissioning of the micro-nano bubble aeration device;

[0075] S2. Take a certain amount of wastewater and put it into the reaction device, and continuously circulate and aerate the wastewater through the micro-nano bubble aeration device for 5 hours, including the following steps:

[0076] S21. Start the micro-nano bubble aeration device, and the filtering device filters the oxygen in the oxygen generation device. The filtered oxygen enters the ozone generation device through the gas flow control device to generate ozone;

[0077] S22. Adjust the ozone gas flow to 0.4 L / min, and detect the ozone concentration through the concentration detection device to reach 165 mg / L;

[0078] S23. After the ozone gas concentration is stable, start the micro-nano bubble generation device. The ozone gas enters the interior of the micro-nano bubble generation device through the pipeline. Relying on the uniform and controllable micropores of the silicon carbide ceramic membrane, the ozone gas is dispersed into ozone micro-nano bubbles. After the ozone micro-nano bubbles are released from the membrane surface, they enter the wastewater in the reaction device and undergo an oxidation reaction with the organic matter in the wastewater;

[0079] S24. While the reaction is in progress, turn on the ozone tail gas treatment device to treat the tail gas generated by the reaction;

[0080] S3. According to the amount of wastewater, add a certain amount of nano-flocculant and polymer flocculant PAM to the reaction device, stir at 250 r / min for 50 s through a magnetic stirrer, mix evenly and then stand for 20 min;

[0081] Among them, the input amount of the nano-flocculant is 3 g / L, and the input amount of the polymer flocculant PAM is 2 g / L;

[0082] Among them, the preparation method of the nano-flocculant includes the following steps:

[0083] S31. Prepare nano-nickel oxide and carry out modification treatment to obtain vinyl-modified nano-nickel oxide, including the following steps:

[0084] S311. Dissolve 3 parts of nickel acetate tetrahydrate in 120 parts of deionized water by mass, dropwise add ammonia water while stirring to adjust the pH to 9.8, and continue stirring until nickel hydroxide sol is formed;

[0085] S312. Transfer the nickel hydroxide sol into a reaction kettle and keep it in a furnace at 400 °C for 5 h. Then, filter the product by suction, wash it with deionized water and absolute ethanol until it is neutral, and dry it in vacuum at 60 °C for 24 h to obtain nano nickel oxide;

[0086] S313. Drop the vinyl silane coupling agent onto the surface of the nano nickel oxide, stir evenly, and then add acrylic acid. The mass ratio of the vinyl silane coupling agent, nano nickel oxide, and acrylic acid is 3:25:4. Stir and react for 1.5 h to obtain vinyl-modified nano nickel oxide;

[0087] S32. Add 4 parts of vinyl-modified nano nickel oxide, 8 parts of acrylamide, 12 parts of dimethyldiallylammonium chloride, 6 parts of activated carbon, and 3 parts of cerium nitrate by mass to 30 parts of deionized water. After fully stirring and dissolving, prepare a monomer mixed solution with a certain concentration, and lower the temperature of the monomer mixed solution to 2 °C;

[0088] S33. Weigh 2 parts of ammonium persulfate and 4 parts of sodium bisulfite by mass respectively, and dissolve them in 8 parts of deionized water to prepare an initiator solution with a certain concentration;

[0089] S34. Introduce nitrogen into the polymerization kettle for 25 min to remove oxygen in the system;

[0090] S35. Transfer the prepared monomer solution into the polymerization kettle, and after introducing nitrogen at a flow rate of 65 m 3 / h for 1.5 h, add the initiator solution to initiate the polymerization reaction, and the polymerization reaction lasts for 5 h;

[0091] S36. After the reaction is completed, pour the reaction solution into a large amount of absolute ethanol to precipitate the polymer. The volume ratio of absolute ethanol to the reaction solution is 3:1. Stir to make the precipitation more complete, and let it stand for 15 min;

[0092] S37. Filter out the precipitate, wash it with absolute ethanol multiple times to remove unreacted impurities, and perform suction filtration after each washing until no impurities are detected in the washing liquid;

[0093] S38. Place the washed product in a vacuum drying oven and dry it at 35 °C for 2 h to obtain a dried nano flocculant;

[0094] S4. Wait for the solution in the reaction device to precipitate and stratify, and take the supernatant;

[0095] S5. When the operation duration of the micro-nano bubble generating device reaches 3 h or the pressure difference across the silicon carbide ceramic membrane exceeds 0.2 MPa, the backwashing device automatically backwashes the micro-nano bubble generating device for 20 min continuously. Meanwhile, a certain amount of chemical agent is regularly added to the reaction device to prevent pollutants from depositing on the surface of the silicon carbide ceramic membrane in the micro-nano bubble generating device.

[0096] Among them, the chemical agent is a dispersant and a cleaning agent. The addition amount of the dispersant is 15 mg / L, and the addition amount of the cleaning agent is 6 mg / L.

[0097] Example 3: Please refer to Figure 1 As shown, a high-efficiency energy-saving anti-clogging nano-bubble aeration process based on a silicon carbide ceramic membrane includes the following steps:

[0098] S1. Complete the installation and commissioning of the micro-nano bubble aeration device.

[0099] S2. Take a certain amount of wastewater and put it into the reaction device. Continuously circulate and aerate the wastewater through the micro-nano bubble aeration device for 6 h, including the following steps:

[0100] S21. Start the micro-nano bubble aeration device. The filtration device filters the oxygen in the oxygen generating device, and the filtered oxygen enters the ozone generating device through the gas flow control device to generate ozone.

[0101] S22. Adjust the ozone gas flow to 0.6 L / min, and detect the ozone concentration to reach 180 mg / L through the concentration detection device.

[0102] S23. After the ozone gas concentration is stable, start the micro-nano bubble generating device. The ozone gas enters the interior of the micro-nano bubble generating device through the pipeline. Relying on the uniform and controllable micropores of the silicon carbide ceramic membrane, the ozone gas is dispersed into ozone micro-nano bubbles. After the ozone micro-nano bubbles are released from the membrane surface, they enter the wastewater in the reaction device and undergo an oxidation reaction with the organic matter in the wastewater.

[0103] S24. While the reaction is taking place, turn on the ozone tail gas treatment device to treat the tail gas generated by the reaction.

[0104] S3. According to the amount of wastewater, add a certain amount of nano-flocculant and polymer flocculant PAM to the reaction device, stir for 60 s under the condition of 300 r / min by a magnetic stirrer, mix evenly and then stand for 30 min.

[0105] Among them, the input amount of the nano-flocculant is 4 g / L, and the input amount of the polymer flocculant PAM is 3 g / L.

[0106] Among them, the preparation method of the nano-flocculant includes the following steps:

[0107] S31. Prepare nano nickel oxide and carry out modification treatment to obtain vinyl-modified nano nickel oxide, including the following steps:

[0108] S311. Dissolve 3 parts of nickel acetate tetrahydrate in 130 parts of deionized water by mass, dropwise add ammonia water while stirring to adjust the pH to 10, and continue stirring until nickel hydroxide sol is formed;

[0109] S312. Transfer the nickel hydroxide sol into a reaction kettle and keep it in an oven at 400 °C for 6 h. Then, filter the product by suction, wash it with deionized water and absolute ethanol until it is neutral, and dry it in vacuum at 60 °C for 24 h to obtain nano nickel oxide;

[0110] S313. Dropwise add vinyl silane coupling agent to the surface of nano nickel oxide, stir evenly, then add acrylic acid. The mass ratio of vinyl silane coupling agent, nano nickel oxide, and acrylic acid is 4:25:5, and stir and react for 2 h to obtain vinyl-modified nano nickel oxide;

[0111] S32. Add 5 parts of vinyl-modified nano nickel oxide, 11 parts of acrylamide, 16 parts of dimethyldiallylammonium chloride, 7 parts of activated carbon, and 4 parts of cerium nitrate by mass to 37 parts of deionized water, fully stir and dissolve to prepare a monomer mixed solution with a certain concentration, and lower the temperature of the monomer mixed solution to 3 °C;

[0112] S33. Weigh 3 parts of ammonium persulfate and 5 parts of sodium bisulfite by mass respectively, and dissolve them in 12 parts of deionized water to prepare an initiator solution with a certain concentration;

[0113] S34. Introduce nitrogen into the polymerization kettle for 30 min to remove oxygen in the system;

[0114] S35. Transfer the prepared monomer solution into the polymerization kettle, and after introducing nitrogen at a flow rate of 65 m 3 / h for 1.5 h, add the initiator solution to initiate the polymerization reaction, and carry out the polymerization reaction for 5 h;

[0115] S36. After the reaction is completed, pour the reaction solution into a large amount of absolute ethanol to precipitate the polymer. The volume ratio of absolute ethanol to the reaction solution is 3:1. Stir to make the precipitation more complete and let it stand for 25 min;

[0116] S37. Filter out the precipitate, wash it with absolute ethanol multiple times to remove unreacted impurities, and carry out suction filtration after each washing until no impurities can be detected in the washing solution;

[0117] S38. Place the washed product in a vacuum drying oven and dry it at 40 °C for 3 h to obtain a dried nano flocculant;

[0118] S4. Wait for the solution in the reaction device to precipitate and stratify, and take the supernatant.

[0119] S5. When the operation duration of the micro-nano bubble generating device reaches 3 h or the pressure difference across the silicon carbide ceramic membrane exceeds 0.2 MPa, the backwashing device automatically backwashes the micro-nano bubble generating device for 30 min. Meanwhile, a certain amount of chemical agent is regularly added to the reaction device to prevent pollutants from depositing on the surface of the silicon carbide ceramic membrane in the micro-nano bubble generating device.

[0120] Among them, the chemical agent is a dispersant and a cleaning agent. The addition amount of the dispersant is 20 mg / L, and the addition amount of the cleaning agent is 10 mg / L.

[0121] Comparative Example 1: Please refer to Figure 1 As shown, this embodiment provides an energy-efficient and anti-clogging nano-bubble aeration process based on a silicon carbide ceramic membrane. Its process is generally the same as that of Example 1. The main difference is that: in step S3, no nano-flocculant is added.

[0122] Comparative Example 2: Please refer to Figure 1 As shown, this embodiment provides an energy-efficient and anti-clogging nano-bubble aeration process based on a silicon carbide ceramic membrane. Its process is generally the same as that of Example 1. The main difference is that: in step S3, no polymer flocculant PAM is added.

[0123] Comparative Example 3: Please refer to Figure 1 As shown, this embodiment provides an energy-efficient and anti-clogging nano-bubble aeration process based on a silicon carbide ceramic membrane. Its process is generally the same as that of Example 1. The main difference is that: in the micro-nano bubble generating device, no silicon carbide ceramic membrane is used.

[0124] Test experiment: Denote the wastewater treated by the aeration processes of Examples 1 to 3 as Example Groups 1 to 3, and denote the wastewater treated by the aeration processes of Comparative Examples 1 to 3 as Comparative Groups 1 to 3. According to the GB18918-2002 standard, test the COD removal rate, NH 3 -N removal rate, and TOC removal rate of the wastewater in Experimental Groups 1 to 3 and Comparative Groups 1 to 3 respectively, and record the relevant data in Table 1.

[0125] Table 1: Test data record table

[0126]

[0127]

[0128] As can be seen from Table 1, compared with Comparative Groups 1 to 3, the wastewater treated by the aeration processes of Examples 1 to 3 can significantly improve the COD removal rate, NH 3-N removal rate and TOC removal rate. When treating wastewater by the aeration process of Example 1, first complete the installation and commissioning of the micro-nano bubble aeration device. Take a certain amount of wastewater and put it into the reaction device. Continuously circulate and aerate the wastewater through the micro-nano bubble aeration device for 3 hours. According to the amount of wastewater, add a certain amount of nano-flocculant and polymer flocculant PAM into the reaction device. Stir for 30 seconds under the condition of 200 r / min by a magnetic stirrer, let it stand for 10 minutes after mixing evenly. Wait for the solution in the reaction device to precipitate and stratify, and take the supernatant. When the operation time of the micro-nano bubble generating device reaches 3 hours or the pressure difference across the silicon carbide ceramic membrane exceeds 0.2 MPa, the backwashing device automatically backwashes the micro-nano bubble generating device for 15 minutes continuously. At the same time, regularly add a certain amount of chemical agents into the reaction device to prevent pollutants from depositing on the surface of the silicon carbide ceramic membrane in the micro-nano bubble generating device. The chemical agents are dispersant and cleaning agent. The addition amount of the dispersant is 10 mg / L, and the addition amount of the cleaning agent is 4 mg / L. Measure the COD of the wastewater and the supernatant, calculate the COD removal rate, and for the wastewater treated by the aeration process of Example 1, the COD removal rate, NH 3 -N removal rate and TOC removal rate are the highest, which are 88.8%, 90.2% and 75.3% respectively;

[0129] When comparing Example Groups 1 to 3 with Comparative Group 1, when treating wastewater by the aeration process of Comparative Example 1, no nano-flocculant was added. The COD removal rate, NH 3 -N removal rate and TOC removal rate in Comparative Group 1 decreased. And in Example 1, when adding a certain amount of nano-flocculant and polymer flocculant PAM into the reaction device according to the amount of wastewater, the input amount of the nano-flocculant is 2 g / L, and the input amount of the polymer flocculant PAM is 1 g / L, which can significantly improve the COD removal rate, NH 3 -N removal rate and TOC removal rate in the wastewater.

[0130] In this invention, when treating wastewater by the aeration process of Example 1, by adding nano-flocculant to the wastewater, this aeration process combines micro-nano ozone bubbles with nano-flocculant. The nano-flocculant can effectively remove impurities such as suspended particles and colloidal substances in the wastewater during wastewater treatment. After the wastewater undergoes good flocculation and precipitation treatment and enters the aeration process of the silicon carbide ceramic membrane, it can reduce the probability of pollutant attachment on the membrane surface and lower the risk of membrane blockage, thereby ensuring that nano-bubbles can be generated stably and efficiently and maintaining the oxygen transfer efficiency of the aeration process. At the same time, the nano-bubbles generated by the silicon carbide ceramic membrane in the micro-nano bubble generating device can greatly increase the gas-liquid contact area, improve the oxygen transfer efficiency, thereby accelerating the sewage treatment speed and improving the treatment effect. Compared with the traditional aeration process, the aeration process of this invention has reduced energy consumption and can effectively reduce the sewage treatment cost;

[0131] By adding a filtering device after the oxygen generation device, the gas passing through the micro-nano bubble generation device can be filtered to reduce the impurities in the gas. At the same time, the micro-nano bubble generation device is improved by adding a pressure detection device and a backwashing device. When the operation time of the micro-nano bubble generation device reaches 3 h or the pressure difference across the silicon carbide ceramic membrane exceeds 0.2 MPa, the backwashing device automatically performs backwashing on the micro-nano bubble generation device. In addition, a certain amount of chemical agent is regularly added to the reaction device to prevent pollutants from depositing on the surface of the silicon carbide ceramic membrane in the micro-nano bubble generation device. Through the comprehensive application of various anti-blocking measures, the aeration process of the present invention effectively solves the problem of easy blockage of the membrane material in the traditional aeration process, extends the service life of the membrane module, and reduces the equipment maintenance cost.

[0132] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A high-efficiency, energy-saving and anti-blocking nanobubble aeration process based on silicon carbide ceramic membrane, characterized in that: The following steps are involved: S1. Complete the installation and commissioning of the micro-nano bubble aeration device, and the devices used during the installation include oxygen generator, filter, gas flow control device, ozone generator, concentration detection device, micro-nano bubble generating equipment, backwashing device, pressure detection device, controller, reaction device and ozone tail gas treatment device; S2. Take a certain amount of wastewater and put it into the reaction device, and use the micro-nano bubble aeration device to continuously circulate and aerate the wastewater for 3 to 6 hours; S3. According to the amount of wastewater, add a certain amount of nano-flocculant and polymer flocculant PAM to the reaction device, stir for 30 to 60 seconds at 200 to 300 r / min using a magnetic stirrer, mix well and let stand for 10 to 30 minutes; S4, the solution in the reaction device is precipitated and layered, the supernatant is taken, and analyzed on a multi-parameter colorimeter, the COD of the wastewater and the supernatant is determined according to the corresponding procedure, and the COD removal rate is calculated; S5. When the operation time of the micro-nano bubble generating device reaches 3h or the pressure difference on both sides of the silicon carbide ceramic membrane exceeds 0.2MPa, the backwashing device automatically backwashes the micro-nano bubble generating device, and at the same time regularly adds a certain amount of chemical agent to the reaction device to prevent pollutants from being deposited on the surface of the silicon carbide ceramic membrane in the micro-nano bubble generating device.

2. The high-efficiency, energy-saving and anti-blocking nanobubble aeration process based on silicon carbide ceramic membrane according to claim 1 is characterized in that: In step S1, the installation and commissioning of the micro-nano bubble aeration device includes the following steps: S11, installing pressure detection devices on both sides of the silicon carbide ceramic membrane in the micro-nano bubble generating device, and installing the backwashing device and the micro-nano bubble generating device; S12, install the micro-nano bubble generating device in the reaction device according to the design requirements, then connect the ozone tail gas treatment device with the reaction device, connect the pipelines between the oxygen generating device, the filtering device, the gas flow control device, the ozone generating device, the concentration detection device and the micro-nano bubble generating device, and check whether the pipeline connection is tight and whether there is any leakage; S13, connecting the controller with the above-mentioned devices to obtain a micro-nano bubble aeration device, and debugging the micro-nano bubble aeration device, adjusting the gas flow through the gas flow control device to meet the design requirements, and checking whether the micro-nano bubble generating device is working normally, and observing whether bubbles are evenly released from the membrane surface.

3. The high-efficiency, energy-saving and anti-blocking nanobubble aeration process based on silicon carbide ceramic membrane according to claim 1 is characterized in that: In step S2, the wastewater is continuously aerated by a micro-nano bubble aeration device, including the following steps: S21, starting the micro-nano bubble aeration device, the filtering device filters the oxygen in the oxygen generating device, and the filtered oxygen enters the ozone generating device through the gas flow control device to generate ozone; S22, adjust the ozone gas flow rate to 0.3-0.6 L / min, and detect the ozone concentration through the concentration detection device to reach 150-180 mg / L; S23, after the concentration of ozone gas is stabilized, the micro-nano bubble generating device is started, and the ozone gas enters the micro-nano bubble generating device through the pipeline, and the ozone gas is dispersed into ozone micro-nano bubbles by means of the uniform and controllable micropores of the silicon carbide ceramic membrane, and the ozone micro-nano bubbles are released from the membrane surface and enter the wastewater of the reaction device, and undergo oxidation reaction with organic matter in the wastewater; S24. While reacting, open the ozone tail gas treatment device to treat the tail gas generated by the reaction.

4. The high-efficiency, energy-saving and anti-blocking nanobubble aeration process based on silicon carbide ceramic membrane according to claim 1 is characterized in that: In step S3, according to the amount of wastewater, the input amount of the nano-flocculant is 2-4 g / L, and the input amount of the polymer flocculant PAM is 1-3 g / L.

5. The high-efficiency, energy-saving and anti-blocking nanobubble aeration process based on silicon carbide ceramic membrane according to claim 1 is characterized in that: In step S3, the method for preparing the nano flocculant comprises the following steps: S31, preparing nano nickel oxide and performing modification treatment to obtain vinyl-modified nano nickel oxide; S32, adding 2 to 5 parts of vinyl-modified nano nickel oxide, 5 to 11 parts of acrylamide, 10 to 16 parts of dimethyldiallylammonium chloride, 5 to 7 parts of activated carbon and 1 to 4 parts of cerium nitrate to 20 to 37 parts of deionized water by mass, stirring and dissolving them fully, preparing a monomer mixed solution of a certain concentration, and reducing the temperature of the monomer mixed solution to 0 to 3°C; S33, weighing 1 to 3 parts of ammonium persulfate and 2 to 5 parts of sodium bisulfite by mass, and dissolving them in 5 to 12 parts of deionized water to prepare an initiator solution of a certain concentration; S34, introducing nitrogen into the polymerization kettle for 20 to 30 minutes to remove oxygen from the system; S35, transfer the prepared monomer solution into the polymerization kettle and heat at 65m 3 After nitrogen is introduced at a flow rate of / h for 1 to 1.5h, an initiator solution is added to initiate the polymerization reaction, and the polymerization reaction is continued for 4 to 5h; S36. After the reaction is completed, pour the reaction solution into a large amount of anhydrous ethanol to precipitate the polymer. The volume ratio of anhydrous ethanol to the reaction solution is 2 to 3:

1. Stir to make the precipitation more complete and let it stand for 10 to 25 minutes. S37, filtering out the precipitate, washing with anhydrous ethanol for multiple times to remove unreacted impurities, and filtering after each washing until no impurities are detected in the washing liquid; S38, placing the washed product in a vacuum drying oven, and drying at 30-40°C for 2-3 hours to obtain a dry nano-flocculant.

6. The high-efficiency, energy-saving and anti-blocking nanobubble aeration process based on silicon carbide ceramic membrane according to claim 5 is characterized in that: In step S31, nano nickel oxide is prepared and modified to obtain vinyl-modified nano nickel oxide, comprising the following steps: S311, dissolving 2 to 3 parts of nickel acetate tetrahydrate in 110 to 130 parts of deionized water by mass, adding ammonia water dropwise while stirring to adjust the pH to 9.7 to 10, and continuing to stir until a nickel hydroxide sol is generated; S312, transferring the nickel hydroxide sol into a reaction kettle and placing it in a furnace at 400° C. for 4 to 6 hours, then filtering the product, washing it with deionized water and anhydrous ethanol until it is neutral, and drying it under vacuum at 60° C. for 24 hours to obtain nano nickel oxide; S313. Add vinyl silane coupling agent dropwise to the surface of nano nickel oxide, stir evenly, and then add acrylic acid. The mass ratio of vinyl silane coupling agent, nano nickel oxide and acrylic acid is 2-4:25:3-5. Stir and react for 1-2 hours to obtain vinyl modified nano nickel oxide.

7. The high-efficiency, energy-saving and anti-blocking nanobubble aeration process based on silicon carbide ceramic membrane according to claim 1 is characterized in that: In step S5, the backwashing device automatically backwashes the micro-nano bubble generating device, including the following steps: S51. When the operation time of the micro-nano bubble generating device reaches 3 hours or the pressure difference on both sides of the silicon carbide ceramic membrane exceeds 0.2MPa, the controller automatically shuts down the oxygen generating device and issues a prompt sound through the prompter; S52, the controller automatically opens the valve of the backwashing device, so that the high-pressure gas or liquid passes through the silicon carbide ceramic membrane of the micro-nano bubble generating device in reverse at a specific pressure and flow rate, and automatically backwashes the micro-nano bubble generating device; S53, continue backwashing for 15 to 30 minutes, and judge the backwashing effect by observing the water quality of the backwashing drainage during the process. When the drainage is clear and has no obvious impurities, turn off the backwashing device through the controller.

8. The high-efficiency, energy-saving and anti-blocking nanobubble aeration process based on silicon carbide ceramic membrane according to claim 1 is characterized in that: In step S5, the chemical agents are dispersants and cleaning agents, the added amount of the dispersants is 10-20 mg / L, and the added amount of the cleaning agents is 4-10 mg / L.

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