A system and method for electrochemical softening and disinfection of wastewater using flue gas CO2

Abstract

The application provides a system and method for treating wastewater by using flue gas CO2 and electrochemical dehardening and sterilization, wherein the system comprises an electrochemical treatment device, an ultrasonic descaling device, a conical sedimentation tank and a flue gas treatment device. The electrochemical treatment device is internally provided with a cathode and an anode; the ultrasonic descaling device is installed in the electrochemical treatment device; the conical sedimentation tank is located below the electrochemical treatment device, and is internally provided with an inclined tube clarifier and is provided with a residue discharge port at the bottom; and the flue gas treatment device comprises a flue gas pipe and a fan, the flue gas pipe is connected to the fan and extends into the lower part of the electrochemical treatment device, and a plurality of aeration holes are formed in the wastewater contact section of the flue gas pipe. The system can quickly and efficiently supplement CO3 2‑ in the wastewater on the one hand, and can maintain the water quality of the electrochemical treatment system in weak acidity, so that a high concentration of HClO is generated in the water, thereby having a significant sterilization effect. 2+ The system can improve the Ca 2+ and Mg precipitation removal effect of the wastewater, and can maintain the water quality of the electrochemical treatment system in weak acidity, so that a high concentration of HClO is generated in the water, thereby having a significant sterilization effect.

Description

Technical Field

[0001] This invention relates to the technical field of wastewater treatment, and in particular to a system and method for treating wastewater by using flue gas CO2 in conjunction with electrochemical hardening and sterilization. Background Technology

[0002] In the process of modern industrial development, numerous industries such as thermal power, metallurgy, chemicals, and cement have flourished, making significant contributions to socio-economic growth. However, these industries generate large amounts of industrial wastewater during operation, and the water quality treatment of circulating water systems has always been a key concern within the industry. If this wastewater is not properly treated, it can lead to reduced equipment and pipeline efficiency and increased energy consumption due to scaling, potentially causing equipment malfunctions, disrupting normal production, and causing serious damage to the surrounding environment. Therefore, wastewater treatment is of paramount importance.

[0003] In past wastewater treatment practices, the commonly used methods for removing hardness from wastewater include chemical precipitation and ion exchange. Chemical precipitation involves adding specific chemical agents to the wastewater to cause calcium and magnesium ions to precipitate and thus remove them. Ion exchange uses ion exchange resins to adsorb and remove calcium and magnesium ions from the wastewater. For wastewater sterilization, a common practice is to add chemical disinfectants, such as chlorine or chlorine dioxide, to kill bacteria and other microorganisms in the wastewater.

[0004] However, existing wastewater treatment methods have significant shortcomings. Chemical precipitation and ion exchange for hardening removal are costly and prone to secondary pollution; adding chemical disinfectants may generate harmful disinfection byproducts, posing new environmental risks. More importantly, existing treatment methods struggle to simultaneously and efficiently achieve both hardening removal and sterilization, failing to meet the efficiency and environmental requirements of actual industrial production for wastewater treatment. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defects in the prior art, thereby providing a system and method for treating wastewater by using flue gas CO2 in conjunction with electrochemical hardening and sterilization.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A wastewater electrochemical hardening and sterilization treatment system utilizing flue gas CO2 in conjunction with wastewater includes: An electrochemical treatment device, wherein the electrochemical treatment device is provided with a cathode and an anode; An ultrasonic descaling device is installed inside the electrochemical treatment device. A conical sedimentation tank is located below the electrochemical treatment device. The conical sedimentation tank is equipped with an inclined tube clarifier inside and a slag discharge port is provided at the bottom of the conical sedimentation tank. A flue gas co-treatment device includes a flue gas pipe and a first fan. The flue gas pipe is connected to the first fan and extends into the lower part of the electrochemical treatment device. Multiple aeration holes are opened in the wastewater contact section of the flue gas pipe. in, The system introduces CO2 into the wastewater through the flue gas co-treatment device, causing the CO2 to react with water to produce carbonic acid and bicarbonate ions, thus replenishing the CO3 in the wastewater. 2- Ca removal by precipitation 2+ and Mg 2+ ; The CO2 dosage is adjusted by the flue gas co-treatment device to maintain the pH of the wastewater in a slightly acidic range, so that the ClO generated at the anode of the electrochemical treatment device can be controlled. - With H + They combine to form HClO.

[0007] In the above scheme, by integrating the electrochemical treatment device, ultrasonic descaling device, conical sedimentation tank and flue gas co-treatment device into one unit, and setting the conical sedimentation tank below the electrochemical treatment device, the carbonate precipitate generated during the electrochemical treatment process can fall directly into the conical sedimentation tank by gravity, without the need for additional precipitate conveying equipment, which simplifies the system structure and reduces equipment investment and operating energy consumption.

[0008] Furthermore, by extending the flue gas pipe into the lower part of the electrochemical treatment device and opening multiple aeration holes in the wastewater contact section, the first blower sends CO2-containing flue gas into the wastewater to form fine bubbles, increasing the gas-liquid contact area and improving the CO2 dissolution efficiency. Simultaneously, the carbonic acid and bicarbonate ions generated after CO2 dissolution effectively replenish the CO3 in the wastewater. 2- Promote Ca 2+ and Mg 2+ Carbonate precipitates are generated, thereby improving the hardness removal effect; in addition, by adjusting the CO2 dosage, the pH of the wastewater is maintained in a slightly acidic range, so that the ClO generated at the anode... - With H + By combining the generation of HClO, which has a stronger bactericidal effect, efficient sterilization can be achieved without the addition of chemical bactericides. This allows for the simultaneous completion of hardening and sterilization treatments in the same system, and also enables the resource utilization of flue gas CO2.

[0009] Preferably, the cathode and anode are plate-shaped electrodes arranged in parallel; The cathode and anode are made of materials that combine high conductivity and high hydrophobicity, including but not limited to graphene / carbon nanotubes and their derivatives, surface-modified metal-based materials, and conductive polymer composite materials.

[0010] In the above scheme, by setting the cathode and anode as parallel plate electrodes, the electric field distribution between the electrodes is uniform, and the current density in each area is consistent when the wastewater flows between the plates. This avoids the phenomenon of excessively high or low local current, improves the uniformity and stability of the electrochemical reaction, and thus ensures the stability of the hardening removal and sterilization effects.

[0011] Furthermore, by using materials with both high conductivity and high hydrophobicity to make the cathode and anode, the high conductivity reduces the resistance loss of the electrodes, reduces energy waste, and improves current efficiency; the high hydrophobicity makes the electrode surface less susceptible to water wetting, reducing the adhesion of scale such as CaCO3, MgCO3, and Mg(OH)2 to the electrode surface, making the scale easier to detach under gravity or water flow. At the same time, in conjunction with an ultrasonic descaling device, the cleaning cycle of the electrodes is significantly extended, downtime for maintenance is reduced, and the operating efficiency and reliability of the system are improved.

[0012] Preferably, the electrochemical treatment device includes an electrode adjustment assembly for adjusting the distance between the anode and the cathode.

[0013] In the above scheme, by setting an electrode adjustment component in the electrochemical treatment device, the system has the ability to adjust the distance between the anode and the cathode, which increases the adjustability and adaptability of the equipment and allows for flexible adjustment of the electrode configuration according to different operating conditions.

[0014] Furthermore, by adjusting the distance between the anode and cathode, the electric field strength and current density distribution between the electrodes can be altered: when treating wastewater with high hardness or high microbial content, the electrode spacing can be reduced to increase the current density, enhance the electrochemical reaction intensity, and improve hardness removal and sterilization efficiency; when treating wastewater with low hardness or when energy consumption needs to be reduced, the electrode spacing can be increased to reduce the current density and decrease energy consumption. In addition, if an increased scaling trend is detected on the electrode surface during operation, the electrode spacing can be appropriately adjusted to change the water flow state, helping to delay scaling and extend the cleaning cycle. This allows for flexible response to different water quality conditions and treatment needs, improving the system's operational economy and adaptability.

[0015] Preferably, the electrode adjustment assembly includes an electrode fixing frame, which includes a horizontally arranged slide rail and an electrode clamping block slidably mounted on the slide rail. The cathode and anode are respectively fixed on the corresponding electrode clamping blocks. The electrode clamping blocks are provided with locking bolts, and the ends of the locking bolts abut against the slide rail to fix the electrode position.

[0016] In the above scheme, by setting up an electrode fixing frame and arranging a horizontal slide rail and a sliding electrode clamping block on it, the cathode and anode are fixed on the corresponding electrode clamping block respectively, which realizes the adjustment of the position of the electrode in the horizontal direction. The operator can move the electrode clamping block along the slide rail according to the processing needs, thereby changing the relative position between the cathode and anode.

[0017] Furthermore, the locking bolts on the electrode clamping block abut against the slide rail. Once the electrode is adjusted to the target position, tightening the locking bolts secures the electrode clamping block to the slide rail, preventing electrode displacement due to water flow impact or vibration during operation and ensuring the stability of the electrode spacing. When readjustment is needed, simply loosen the locking bolts to slide again, making operation simple and reliable. This structure is simple and compact, with high adjustment precision and reliable fixation, meeting the electrode spacing adjustment requirements under different operating conditions while ensuring the long-term stability and safety of the electrochemical treatment device.

[0018] Preferably, the ultrasonic descaling device includes a plurality of ultrasonic transducers, which are arranged at intervals along the electrode extension direction of the electrochemical treatment device, and the ultrasonic transducers face the surfaces of the cathode and the anode.

[0019] In the above scheme, by setting up multiple ultrasonic transducers and arranging them at intervals along the extension direction of the electrode, the entire length range of the cathode and anode is covered, avoiding the descaling blind spots that exist in single-point ultrasonic descaling devices, ensuring that all areas of the electrode surface can be subjected to ultrasonic waves, and improving the comprehensiveness and uniformity of descaling.

[0020] Furthermore, by arranging the ultrasonic transducers toward the surfaces of the cathode and anode, the ultrasonic energy acts directly on the scale layer on the electrode surface, reducing energy attenuation during propagation in the medium and improving energy utilization efficiency. The cavitation effect and mechanical vibration generated by the ultrasonic waves on the electrode surface can effectively destroy the bonding force between the scale layer and the electrode, causing scale layers such as CaCO3, MgCO3, and Mg(OH)2 to peel off from the electrode surface, maintaining the cleanliness of the electrode surface.

[0021] It should be understood that multiple ultrasonic transducers are arranged at intervals along the electrode extension direction. The number and spacing of the transducers can be flexibly adjusted according to the electrode length and processing requirements to adapt to different specifications of electrochemical treatment devices. At the same time, this arrangement allows each transducer to be responsible for a relatively small electrode area, achieving an overall descaling effect with lower individual power, reducing the load on individual transducers and extending the service life of the ultrasonic descaling device. In addition, when it is necessary to intensify descaling in a specific area, the frequency or power of the corresponding transducer can be adjusted individually to achieve refined descaling control, further improving the system's operating efficiency and reliability.

[0022] Preferably, the portion of the flue gas pipe located in the wastewater is in the shape of an annular coil, and the portion of the flue gas pipe located in the wastewater is provided with multiple aeration nozzles, each aeration nozzle being configured in a one-to-one correspondence with an aeration hole, and each aeration nozzle communicating with the corresponding aeration hole.

[0023] In the above scheme, the part of the flue gas pipe located in the wastewater is set as an annular coil, which increases the distribution range of the flue gas pipe in the wastewater. This allows the flue gas to enter from multiple circumferential positions of the electrochemical treatment device at the same time, avoiding the phenomenon of excessively high local CO2 concentration or uneven distribution caused by single-point aeration, and improving the uniformity of CO2 dispersion in the wastewater.

[0024] Furthermore, by setting up multiple aeration nozzles and connecting them one-to-one with the aeration holes, the flue gas enters the aeration nozzles from the flue gas pipe and is released through the aeration holes. The aeration nozzles can guide and refine the airflow, allowing CO2 to enter the wastewater in the form of finer bubbles, further increasing the gas-liquid contact area and improving the CO2 dissolution efficiency. At the same time, the structural design of the aeration nozzles can adjust the bubble size and spray direction as needed to optimize the aeration effect.

[0025] It should be understood that the annular coil structure, combined with the arrangement of multiple aerators, ensures that bubbles are evenly distributed across the cross-section of the electrochemical treatment device, forming a three-dimensional aeration network that effectively avoids aeration dead zones. The rising bubbles create uniform disturbance to the wastewater, promoting the uniformity of the flow field within the electrochemical treatment device and enhancing the mass transfer process of ions to the electrode surface, thereby improving the efficiency of the electrochemical reaction. Furthermore, when individual aerators become clogged, they can be cleaned or replaced individually without replacing the entire flue pipe, reducing maintenance costs and downtime, and improving the reliability and maintainability of the system.

[0026] Preferably, the flue pipe is provided with a first regulating valve, a pressure gauge and a first flow meter in sequence.

[0027] In the above scheme, a complete flue gas conveying monitoring and regulation unit is constructed by sequentially installing a first regulating valve, a pressure gauge and a first flow meter on the flue gas pipe, thereby realizing the flow and pressure control of the CO2 conveying process.

[0028] Furthermore, operators can read CO2 flow data in real time through the first flow meter to understand the current flue gas intake; monitor pressure changes in the flue gas pipe through the pressure gauge to determine if there is any blockage or leakage in the system; and manually or automatically adjust the CO2 delivery rate through the first regulating valve. These three functions work together to enable the system to adjust the CO2 dosage according to changes in wastewater quality and treatment requirements, providing a fundamental guarantee for subsequent pH control and hardness removal optimization, while also facilitating operation, maintenance, and fault diagnosis.

[0029] Preferably, it further includes: pH sensor, wherein the pH sensor is disposed within the electrochemical treatment device; The controller is electrically connected to both the pH sensor and the first regulating valve.

[0030] In the above scheme, a pH sensor is set up to monitor the pH value of the wastewater in the electrochemical treatment device in real time, and the pH signal is transmitted to the controller. The controller sends a control command to the first regulating valve according to the deviation between the preset pH target value and the measured value, thus forming a closed-loop control system.

[0031] Furthermore, this automatic control system can respond to changes in wastewater pH in real time. When the pH deviates from the weakly acidic range, the controller adjusts the opening of the first regulating valve to increase or decrease the CO2 dosage, allowing the pH to quickly return to the target range, avoiding the lag and inaccuracy of manual adjustment. Simultaneously, the system can effectively cope with pH disturbances caused by fluctuations in influent water quality, consistently maintaining the ClO₂ produced at the anode. - With H + By combining the optimal pH conditions for HClO generation, the stability and reliability of the sterilization effect are ensured, and the intelligent operation of the system is realized.

[0032] Preferably, the bottom of the conical sedimentation tank is provided with a sludge discharge pipe, the sludge discharge port is located at the end of the sludge discharge pipe, the sludge discharge pipe is provided with a second regulating valve, and a sludge thickening tank is connected downstream of the second regulating valve.

[0033] In the above scheme, the sediment at the bottom of the conical sedimentation tank is led out by setting a sludge discharge pipe, and a second regulating valve is set on the sludge discharge pipe to achieve flexible control of the sludge discharge process; the downstream of the second regulating valve is connected to a sludge thickening tank for further thickening of the discharged sediment.

[0034] Furthermore, when the sediment accumulates to a certain amount, the second regulating valve can be opened to discharge the sediment into the sludge thickening tank for volume reduction treatment, thereby reducing the volume of subsequent treatment. By controlling the opening degree and opening time of the second regulating valve, the discharge speed and discharge volume can be adjusted to avoid the impact of a large amount of discharge on the system at one time. The sludge thickening tank thickens the sediment, reducing the water content, which facilitates subsequent transportation and resource utilization. At the same time, the supernatant can be returned to the front end of the system for reprocessing, realizing the recycling of water resources and reducing wastewater discharge.

[0035] A method for treating wastewater using flue gas CO2 in synergy with electrochemical hardening and sterilization, applied to the aforementioned system for treating wastewater using flue gas CO2 in synergy with electrochemical hardening and sterilization, includes the following steps: Flue gas containing CO2 is introduced into the lower part of the electrochemical treatment unit through a flue gas pipe via a first fan. The flue gas comes into direct contact with the wastewater through aeration holes, where CO2 dissolves in the water to generate H2CO3 and HCO3-. - Replenish CO3 in wastewater 2- , with Ca in wastewater 2+ Mg 2+ The reaction produces a carbonate precipitate; An electric field is applied to the electrochemical treatment device to cause an electrochemical reaction between the cathode and anode. The anode removes Cl from the wastewater. - Oxidation to produce ClO - ; By adjusting the CO2 dosage, the pH value of the wastewater in the electrochemical treatment device is maintained in the weakly acidic range, so that the ClO generated at the anode... - With H + The generated HClO is used to sterilize the wastewater. Scale on the surface of electrodes and flow components is removed by ultrasonic descaling device; The carbonate precipitate produced by the electrochemical process settles in the conical sedimentation tank via an inclined tube clarifier and is periodically discharged through the slag discharge port.

[0036] In the above scheme, five steps—flue gas introduction, electric field application, pH control, ultrasonic descaling, and sedimentation separation—are organically integrated to form a complete wastewater treatment process. Each step operates collaboratively within the same system, requiring no intermediate transfers or additional equipment. The process is simple, efficient, and easy to operate and manage. By introducing CO2-containing flue gas through aeration holes into the lower part of the electrochemical treatment device, the flue gas, in the form of fine bubbles, fully contacts the wastewater. The CO2 dissolves to generate H2CO3 and HCO3-. - Effectively replenishes CO3 in wastewater 2- , with Ca 2+ Mg 2+ The reaction produces carbonate precipitates, achieving softening and hardening treatment of wastewater, while simultaneously utilizing waste flue gas as a resource; by applying an electric field in the electrochemical treatment device, the anode removes Cl from the wastewater. - Oxidation to produce ClO - Simultaneously, by adjusting the CO2 dosage, the pH of the wastewater is maintained within a slightly acidic range, allowing ClO2 to... - With H +By combining the chemical process with the more potent bactericidal HClO, sterilization is achieved simultaneously in the same electrochemical process, eliminating the need for additional chemical bactericides, reducing operating costs, and preventing secondary pollution. An ultrasonic descaling device removes scale from the electrodes and flow components online, preventing scale buildup that increases resistance and reduces treatment efficiency, ensuring continuous and stable electrochemical reactions, and extending equipment cleaning cycles and maintenance intervals. A conical sedimentation tank and its internal inclined tube clarifier efficiently separate carbonate precipitates through sedimentation, with the clear water overflowing upwards and the concentrated precipitate periodically discharged through the slag outlet, achieving solid-liquid separation and ensuring effluent quality. This method organically combines multiple functional units, including flue gas CO2 resource utilization, electrochemical hardening removal, electrochemical sterilization, ultrasonic scale prevention, and efficient sedimentation separation, forming a synergistic waste-to-waste treatment process. Each step promotes and supports the others, achieving wastewater treatment that meets standards while simultaneously reducing flue gas CO2 emissions and utilizing resources, resulting in significant environmental and economic benefits.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. By introducing CO2 into the wastewater through a flue gas co-treatment device, the carbonic acid and bicarbonate generated after the CO2 dissolves effectively replenish the CO3 in the wastewater. 2- Promote Ca 2+ and Mg 2+ The formation of carbonate precipitates significantly improves hardness removal efficiency; on the other hand, by adjusting the CO2 dosage, the pH of the wastewater is maintained in a slightly acidic range, allowing the ClO generated at the anode to... - With H + By combining the generation of HClO, which has a stronger bactericidal effect, efficient sterilization and disinfection can be achieved without adding chemical bactericides. At the same time, the resource utilization of flue gas CO2 is realized, achieving the environmental protection effect of treating waste with waste.

[0038] 2. The electrodes are descaled online using an ultrasonic descaling device to prevent scale buildup from increasing resistance and reducing treatment efficiency, thus extending the electrode cleaning cycle. A closed-loop automatic control system composed of a pH sensor and controller monitors and precisely controls the wastewater pH in real time within a slightly acidic range, effectively addressing fluctuations in influent water quality and ensuring the stability of the sterilization effect. Efficient solid-liquid separation is achieved through an inclined tube clarifier in a conical sedimentation tank, ensuring effluent water quality. The overall system operates stably and reliably, with long maintenance intervals and low operating costs.

[0039] 3. By integrating the electrochemical treatment device, ultrasonic descaling device, conical sedimentation tank, and flue gas co-treatment device into one unit, and placing the conical sedimentation tank below the electrochemical treatment device, the precipitates generated during the electrochemical process can directly enter the sedimentation tank by gravity without the need for additional conveying equipment. This simplifies the system structure and reduces investment costs and operating energy consumption. Attached Figure Description

[0040] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of the overall electrochemical hardening and sterilization treatment system in this embodiment.

[0042] Figure 2 This is a schematic diagram of the electrode adjustment assembly in this embodiment.

[0043] Explanation of reference numerals in the attached figures: 1. Electrochemical treatment device; 2. Cathode; 3. Anode; 4. Ultrasonic descaling device; 5. Conical sedimentation tank; 6. Inclined tube clarifier; 7. Slag discharge port; 8. Flue gas pipe; 9. First blower; 10. First regulating valve; 11. Pressure gauge; 12. First flow meter; 13. Aeration hole; 14. Inlet pipe; 15. Outlet pipe; 16. Second flow meter; 17. Third regulating valve; 18. Second blower; 19. Fourth regulating valve; 71. Sludge discharge pipe; 72. Second regulating valve; 73. Sludge thickening tank; 101. Electrode holder; 102. Slide rail; 103. Electrode clamping block; 104. Locking bolt. Detailed Implementation

[0044] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0046] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0047] See Figure 1 This invention provides a flue gas CO2 co-processing wastewater electrochemical hardening and sterilization system, including an electrochemical treatment device 1, an ultrasonic descaling device 4, a conical sedimentation tank 5, and a flue gas co-processing device. The electrochemical treatment device 1 is equipped with a cathode 2 and an anode 3. The ultrasonic descaling device 4 is installed inside the electrochemical treatment device 1. The conical sedimentation tank 5 is located below the electrochemical treatment device 1. The conical sedimentation tank 5 is equipped with an inclined tube clarifier 6. The bottom of the conical sedimentation tank 5 is equipped with a slag discharge port 7. The flue gas co-processing device includes a flue gas pipe 8 and a first blower 9. The flue gas pipe 8 is connected to the first blower 9 and extends into the lower part of the electrochemical treatment device 1. Multiple aeration holes 13 are opened in the wastewater contact section of the flue gas pipe 8.

[0048] The system introduces CO2 into the wastewater through a flue gas co-treatment device, causing the CO2 to react with water to produce carbonic acid and bicarbonate ions, thus replenishing the CO3 in the wastewater. 2- Ca removal by precipitation 2+ and Mg 2+ The CO2 dosage is adjusted by the flue gas co-treatment device to maintain the pH of the wastewater in a slightly acidic range, so that the ClO generated at the anode 3 of the electrochemical treatment device 1 can be controlled. - With H + They combine to form HClO.

[0049] Specifically, the electrochemical treatment device 1 is the core reaction unit of this system, which contains a cathode 2 and an anode 3. The cathode 2 and anode 3 are connected to an external power source. When the system is running, the external power source applies an electric field to the cathode 2 and anode 3, causing ions in the wastewater to undergo an electrochemical reaction on the electrode surfaces. A reduction reaction occurs on the surface of the cathode 2, producing OH-. - An oxidation reaction occurs on the surface of anode 3, releasing Cl from the wastewater. - Oxidation to produce ClO - The shell of the electrochemical treatment device 1 can be made of corrosion-resistant materials, such as stainless steel with an anti-corrosion lining or fiberglass, to meet the treatment requirements of different water qualities. The arrangement of the cathode 2 and anode 3 can be designed according to the treatment volume and water quality characteristics, for example, by using multiple sets of electrodes in parallel or series to improve treatment capacity.

[0050] The ultrasonic descaling device 4 is installed inside the electrochemical treatment device 1, and its specific location can be set according to the electrode layout. When the ultrasonic descaling device 4 is working, it generates high-frequency mechanical vibrations, which propagate through the medium to the surfaces of the cathode 2 and anode 3, producing cavitation effects and mechanical impact forces on the electrode surfaces. This causes micro-cracks in the scale layer adhering to the electrode surfaces, gradually peeling it off. The ultrasonic descaling device 4 can be set to continuous or intermittent operation modes. For example, intermittent operation can be used in the initial stage when scaling is light to reduce energy consumption, while switching to continuous operation when scaling becomes heavier due to longer operating times enhances the descaling effect. The power of the ultrasonic descaling device 4 can be configured according to the volume and electrode area of ​​the electrochemical treatment device 1 to ensure that the ultrasonic energy can effectively cover the entire electrode area.

[0051] The conical sedimentation tank 5 is located below the electrochemical treatment unit 1, and the two can be connected by flanges or directly welded to form an integrated structure. During the electrochemical treatment process, the carbonate precipitate naturally settles under gravity and enters the conical sedimentation tank 5. The conical sedimentation tank 5 adopts a cone-shaped structure that is wider at the top and narrower at the bottom, which facilitates the concentration of precipitates at the bottom. Inside the conical sedimentation tank 5 is an inclined tube clarifier 6 (the inclined tube clarifier 6 is existing technology, and its specific working principle and structure will not be described here). The inclined tube clarifier 6 consists of multiple inclined pipes. When wastewater containing precipitates flows upward through the inclined tube clarifier 6, the precipitates settle inside the inclined tubes and slide down the pipe walls to the bottom of the conical sedimentation tank 5, while the clear water overflows from the top of the inclined tube clarifier 6, achieving solid-liquid separation. The bottom of the conical sedimentation tank 5 has a slag discharge port 7, through which precipitates accumulate to a certain amount and are periodically discharged from the system.

[0052] The flue gas co-treatment device is used to introduce CO2-containing flue gas into the system. It includes a flue gas pipe 8 and a first blower 9. One end of the flue gas pipe 8 is connected to the outlet of the first blower 9, and the other end extends into the lower part of the electrochemical treatment device 1. The first blower 9 provides the power to pressurize the CO2-containing flue gas and send it into the flue gas pipe 8. The wastewater contact section of the flue gas pipe 8, that is, the part located below the liquid surface inside the electrochemical treatment device 1, has multiple aeration holes 13. When the flue gas is ejected from the aeration holes 13, it is broken into fine bubbles and fully mixes with the wastewater. The pore size and distribution density of the aeration holes 13 can be designed according to the flue gas flow rate and bubble size requirements. For example, using a smaller pore size can obtain finer bubbles, increase the gas-liquid contact area, and improve the CO2 dissolution efficiency. The CO2 concentration in the flue gas can be determined according to the actual gas source conditions. For example, industrial tail gas containing CO2, such as flue gas from thermal power plant boilers or cement kiln tail gas, can be used directly.

[0053] During system operation, the flue gas co-treatment device continuously introduces CO2 into the electrochemical treatment device 1. CO2 dissolves in water and undergoes the following reaction: CO2 + H2O → H2CO3 → H + +HCO3- ; The generated HCO3 - OH produced by the reaction with the cathode - Further reaction produces CO3 2- HCO3 - +OH - →CO3 2- +H2O; CO3 2- With Ca in wastewater 2+ Mg 2+ The reaction produces CaCO3 and MgCO3 precipitates: Ca 2+ +CO3 2- →CaCO3↓, Mg 2+ +CO3 2- →MgCO3↓.

[0054] Through this process, the introduction of CO2 effectively replenishes the CO3 in the wastewater. 2- This promotes the precipitation and removal of hardness ions, overcoming the limitations of simple electrochemical treatment due to HCO3. - The problem of low efficiency in removing hardeners due to insufficient capacity.

[0055] Simultaneously, by regulating the CO2 dosage through the flue gas co-treatment device, the pH value of the wastewater in electrochemical treatment unit 1 can be precisely controlled and maintained within the weakly acidic range. Since the carbonic acid formed after CO2 dissolves is a weak acid, appropriately introducing CO2 can stabilize the wastewater pH within the weakly acidic range. Under these pH conditions, the ClO produced by anode 3... - With H in the solution + Combine to form HClO:ClO - +H + →HClO.

[0056] The redox potential of HClO is higher than that of ClO. - Its bactericidal ability is ClO - It is tens to hundreds of times stronger than CO2, thus achieving highly efficient sterilization and disinfection at lower concentrations. By controlling the amount of CO2 added, the pH is stably maintained in a slightly acidic range, ensuring the effectiveness of ClO2. - The efficient conversion to HClO enables simultaneous sterilization of wastewater without the addition of additional chemical disinfectants.

[0057] The aforementioned flue gas CO2 co-treatment system for wastewater electrochemical hardening and sterilization integrates the electrochemical treatment unit 1, the ultrasonic descaling unit 4, the conical sedimentation tank 5, and the flue gas co-treatment unit into a single unit. The conical sedimentation tank 5 is positioned below the electrochemical treatment unit 1, allowing the carbonate precipitates generated during the electrochemical treatment process to fall directly into the conical sedimentation tank by gravity, eliminating the need for additional precipitate conveying equipment. This simplifies the system structure and reduces equipment investment and operating energy consumption. By introducing CO2 into the wastewater through the flue gas co-treatment unit, the carbonate and bicarbonate ions generated after CO2 dissolution effectively replenish the CO3 in the wastewater. 2- Promote Ca 2+ and Mg 2+ The formation of carbonate precipitates significantly improves hardness removal efficiency; on the other hand, by adjusting the CO2 dosage, the pH of the wastewater is maintained in a slightly acidic range, allowing the ClO generated at the anode to... - With H + By combining the generation of HClO, which has a stronger bactericidal effect, efficient sterilization and disinfection can be achieved without adding chemical bactericides. At the same time, the resource utilization of flue gas CO2 is realized, achieving the environmental protection effect of treating waste with waste.

[0058] The following description, in conjunction with the accompanying drawings and specific embodiments, provides a more detailed account of the flue gas CO2 synergistic wastewater electrochemical hardening and sterilization treatment system provided by the present invention.

[0059] Based on any of the above specific embodiments, refer to Figure 1 The cathode 2 and anode 3 are parallel plate-shaped electrodes. The cathode 2 and anode 3 are made of materials with both high conductivity and high hydrophobicity, including but not limited to graphene / carbon nanotubes and their derivative materials, surface-modified metal-based materials, and conductive polymer composite materials.

[0060] Specifically, the cathode 2 and anode 3 adopt a parallel plate structure, arranged at intervals to form a uniform electric field distribution area. The spacing between the parallel plate electrodes can be preset according to the size of the electrochemical treatment device 1 and the treatment requirements, for example, it can be set to a fixed value between 10 mm and 50 mm. When wastewater flows between the plates, due to the uniform electric field distribution, the current density in each area is basically the same, avoiding overheating caused by excessively high local current or insufficient reaction caused by excessively low local current. This ensures that the entire electrode surface can undergo a uniform electrochemical reaction, improving the stability of hardening removal and sterilization effects.

[0061] The cathode 2 and anode 3 are made of materials that combine high conductivity and high hydrophobicity. High conductivity materials can reduce the resistance of the electrodes themselves, reduce the loss of electrical energy as heat, and allow more electrical energy to be used for electrochemical reactions, thus improving current efficiency. For example, graphene and carbon nanotubes and their derivatives have excellent conductivity, and their unique two-dimensional or one-dimensional structures provide efficient electron transport channels; surface-modified metal-based materials, such as silver nanomaterials or copper nanomaterials modified with hydrophobic organic materials, retain the good conductivity of metals while being endowed with hydrophobic properties through surface modification; conductive polymer composite materials, such as polypyrrole and polyaniline, are inherently conductive, and their surface properties can be adjusted through molecular design.

[0062] The high hydrophobicity makes the electrode surface less susceptible to water wetting, and the Ca in the wastewater... 2+ Mg 2+ With CO3 2- The adhesion of scale layers such as CaCO3 and MgCO3 generated by the reaction to the electrode surface is significantly reduced. With the weakened bond between the scale layer and the electrode surface, it is more easily detached under gravity or water flow. Simultaneously, the mechanical vibration of the ultrasonic descaling device 4 further enhances the scale removal effect. This material characteristic effectively slows down the accumulation rate of scale on the electrode surface, extends the cycle of electrode downtime for cleaning, and improves the continuous operation time and reliability of the system.

[0063] Based on any of the above specific embodiments, refer to Figure 1 and Figure 2 The electrochemical treatment device 1 is equipped with an electrode adjustment component, which is used to adjust the distance between the anode 3 and the cathode 2.

[0064] Specifically, in addition to the cathode 2 and anode 3, the internal space of the electrochemical treatment device 1 also houses an electrode adjustment assembly. This assembly is connected to the electrodes and can move them, thereby changing the relative distance between the cathode 2 and anode 3. The operating end of the electrode adjustment assembly can extend to the outside of the electrochemical treatment device 1 or be located in an easily accessible position, allowing operators to adjust the electrode spacing as needed. By adjusting the electrode spacing, the electric field strength and current density distribution between the electrodes can be changed, thus affecting the rate and efficiency of the electrochemical reaction. For example, when treating wastewater with high hardness or high microbial content, a stronger electrochemical reaction is required to improve the treatment effect. In this case, the electrode spacing can be reduced by using the electrode adjustment assembly, increasing the electric field strength and current density, thereby accelerating the reaction of Ca2+. 2+ Mg 2+ precipitation rate and ClO -The generation rate can be adjusted. When treating low-hardness wastewater or when energy consumption needs to be reduced, the electrode spacing can be increased to operate at a lower current density and reduce power consumption. In addition, if an accelerated scaling rate is detected on the electrode surface during system operation, the electrode spacing can be adjusted appropriately to change the water flow state and the shear force on the electrode surface, thereby helping to slow down the scaling process and extend the electrode cleaning cycle.

[0065] Alternatively, please refer to Figure 2 The electrode adjustment assembly includes an electrode fixing frame 101, which includes a horizontally arranged slide rail 102 and an electrode clamping block 103 slidably mounted on the slide rail 102. The cathode 2 and anode 3 are respectively fixed on the corresponding electrode clamping block 103. The electrode clamping block 103 is provided with a locking bolt 104, and the end of the locking bolt 104 abuts against the slide rail 102 to fix the electrode position.

[0066] Specifically, the electrode holder 101, serving as a support base, can be made of insulating materials such as polytetrafluoroethylene, engineering plastics, or metal materials with an insulating coating on the surface, and is installed on the bottom or side wall of the inner wall of the electrochemical treatment device 1. Horizontally extending slide rails 102 are fixedly mounted on the electrode holder 101. The number of slide rails 102 can be determined according to the number and arrangement of the electrodes; for example, two parallel slide rails can be used to provide more stable support. The cross-section of the slide rails 102 can be designed in the shape of a dovetail, T-shape, or circle to ensure the guiding accuracy and load-bearing capacity of the sliding components. The surface of the slide rails 102 is hardened to improve wear resistance and service life.

[0067] Electrode clamping blocks 103 are slidably mounted on the slide rail 102. The number of electrode clamping blocks 103 is the same as the number of electrodes, with two electrode clamping blocks 103 corresponding to each set of cathodes 2 and anodes 3. The bottom of the electrode clamping block 103 is provided with a sliding groove or slider that matches the slide rail 102, allowing the electrode clamping block 103 to move smoothly along the slide rail 102. The main body of the electrode clamping block 103 is provided with a clamping mechanism, such as a clamping groove with a fastening screw, or a spring pressure plate structure, for fixing the edge or end of the electrode. The cathode 2 and anode 3 are respectively mounted on the corresponding electrode clamping blocks 103, and are reliably fixed by the clamping mechanism, ensuring that the electrodes will not loosen due to water flow impact or vibration during long-term operation.

[0068] The electrode clamping block 103 has a threaded through hole on its side or top, and a locking bolt 104 is installed in the threaded through hole. The end of the locking bolt 104 faces the surface of the slide rail 102. When the locking bolt 104 is tightened, its end is tightly against the slide rail 102, and the electrode clamping block 103 is locked in the current position by friction. When it is necessary to adjust the electrode spacing, the operator first uses a tool to loosen the locking bolt 104, so that the end of the locking bolt 104 is out of contact with the slide rail 102. At this time, the electrode clamping block 103 is in a free sliding state. Then, according to the required electrode spacing, the electrode clamping block 103 is pushed along the slide rail 102, which moves the cathode 2 or anode 3. After adjusting to the target position, the locking bolt 104 is tightened again, so that the end of the locking bolt 104 is pressed against the slide rail 102, and the electrode clamping block 103 is fixed. This adjustment structure is simple and reliable, easy to operate, and can adjust the electrode spacing without disassembling other parts, which provides convenience for the flexible operation and maintenance of the system. Meanwhile, the precise fit between the slide rail 102 and the electrode clamping block 103 ensures the smoothness of electrode movement and the accuracy of position adjustment. The locking mechanism of the locking bolt 104 can effectively prevent the electrode from shifting during operation, ensuring the stability and consistency of the electrochemical reaction.

[0069] It should be noted that the electrode holder 101 and its slide rail 102 are detachably installed inside the electrochemical treatment device 1. Specifically, the electrode holder 101 can be detachably fixed to the inner wall or bottom of the electrochemical treatment device 1 by means of bolt connection, slot engagement, or hook connection, which facilitates installation, maintenance, and replacement. When it is necessary to inspect or replace the electrode, the electrode holder 101 can be removed as a whole for external operation, improving the convenience of maintenance.

[0070] Furthermore, the adjustment of the distance between cathode 2 and anode 3 should be performed before adding wastewater into the electrochemical treatment device 1. During initial system installation or when adjusting the electrode spacing, the operator first loosens the locking bolt 104, moves the electrode clamping block 103 along the slide rail 102, adjusts the cathode 2 and anode 3 to the required distance, and then tightens the locking bolt 104 to fix the electrode position. After adjustment, wastewater to be treated is injected into the electrochemical treatment device 1, and the system is started. This sequence of adjustment followed by water injection avoids the influence of water flow resistance on the adjustment accuracy when adjustment is performed in the presence of wastewater, and also prevents damage to the electrode coating caused by friction or collision on the electrode surface during adjustment, ensuring the accuracy of electrode spacing adjustment and the integrity of the electrode surface.

[0071] Based on any of the above specific embodiments, refer to Figure 1 The ultrasonic descaling device 4 includes multiple ultrasonic transducers, which are arranged at intervals along the electrode extension direction of the electrochemical treatment device 1, and the ultrasonic transducers face the surfaces of the cathode 2 and the anode 3.

[0072] Specifically, the ultrasonic descaling device 4 consists of multiple independent ultrasonic transducers, which are fixed inside the electrochemical treatment device 1 by mounting brackets. The core component of the ultrasonic transducer is a piezoelectric ceramic plate. When a high-frequency alternating electric field is applied, the piezoelectric ceramic plate generates mechanical vibration, converting electrical energy into ultrasonic mechanical energy. Multiple ultrasonic transducers are arranged along the extension direction of the electrodes within the electrochemical treatment device 1. For example, for vertically installed plate electrodes, where the electrodes extend vertically, multiple ultrasonic transducers are arranged vertically from top to bottom at intervals; for horizontally installed electrodes, they are arranged horizontally at intervals. This arrangement ensures that each ultrasonic transducer covers a certain range of electrode area, and the ultrasonic action ranges of adjacent transducers overlap, ensuring that there are no descaling blind spots on the entire electrode surface.

[0073] The ultrasonic transducer is installed with its transmitting end facing the surfaces of cathode 2 and anode 3, meaning the ultrasonic energy is directly directed towards the electrode surfaces. The mounting bracket can be designed with an angle-adjustable structure, such as a universal joint or an adjustable angle base. During installation, the transducer's emission direction can be adjusted so that its main acoustic beam axis is perpendicular to the electrode surfaces or points towards them at a certain angle. In this way, the ultrasonic energy propagates to the electrode surfaces via the shortest path, reducing energy attenuation during propagation through the medium and improving energy utilization efficiency.

[0074] When an ultrasonic transducer operates, it emits high-frequency mechanical waves towards the electrode surface, creating alternating compression and rarefaction regions in the liquid medium near the electrode surface, resulting in a cavitation effect. Cavitation refers to the process by which tiny bubbles in the liquid grow, oscillate, and violently collapse under the influence of ultrasound. The collapse of these bubbles generates localized high temperatures, high pressures, and high-speed microjets, which strongly impact and peel off the scale deposits adhering to the electrode surface. Simultaneously, as the ultrasound propagates at the interface between the electrode substrate and the scale, the difference in acoustic impedance between the two materials causes reflection and refraction, creating shear stress at the interface. This weakens the bond between the scale and the electrode surface, causing microcracks to form and gradually propagate, ultimately leading to the scale detachment.

[0075] Multiple ultrasonic transducers are arranged at intervals along the electrode's extension direction, and the number and spacing of the transducers can be flexibly adjusted according to the actual length and height of the electrode. For example, for an electrode 2 meters long, 5-8 ultrasonic transducers can be evenly distributed, with each transducer covering an electrode area of ​​0.25-0.4 meters. When severe scaling is detected in a certain area of ​​the electrode during system operation, the power of the corresponding ultrasonic transducer can be increased or its frequency adjusted via the controller to achieve targeted and enhanced descaling, while other areas maintain normal operation. This refined control method ensures effective descaling while avoiding unnecessary energy waste, thus improving the operational economy of the ultrasonic descaling device 4.

[0076] Based on any of the above specific embodiments, refer to Figure 1 The portion of the flue gas pipe 8 located in the wastewater is in the shape of a ring coil. The portion of the flue gas pipe 8 located in the wastewater is equipped with multiple aeration nozzles. Each aeration nozzle is corresponding to an aeration hole 13, and the aeration nozzle is connected to the corresponding aeration hole 13.

[0077] Specifically, after the flue gas pipe 8 enters the side wall or top of the electrochemical treatment device 1, the portion below the wastewater surface is constructed as an annular coil. The annular coil can be a single-layer or multi-layer structure, arranged around the lower space of the electrochemical treatment device 1. The diameter of the annular coil is adapted to the cross-sectional dimensions of the electrochemical treatment device 1; for example, it can be a circular or rectangular ring slightly smaller than the inner diameter of the electrochemical treatment device 1, maintaining a certain gap between the outer circumference of the coil and the inner wall of the device. This annular coil structure ensures that the distribution range of the flue gas pipe 8 in the wastewater covers the entire cross-section of the electrochemical treatment device 1, preventing flue gas from being concentrated in localized areas and laying the foundation for subsequent uniform aeration.

[0078] Multiple connecting seats are spaced apart along the circumference and axial direction on the annular coil, and an aeration nozzle is installed on each connecting seat. The aeration nozzle is connected to the flue gas channel inside the annular coil. After the flue gas enters the aeration nozzle from the annular coil, it is released into the wastewater from the aeration hole 13 at the end of the aeration nozzle. The number and distribution density of the aeration nozzles can be determined according to the size and treatment requirements of the electrochemical treatment device 1. For example, for an electrochemical treatment device 1 with a larger diameter, more aeration nozzles can be set to ensure the uniformity of bubble distribution; for a taller device, aeration nozzles can be set in the upper and lower layers of the annular coil to achieve three-dimensional aeration.

[0079] The aerator nozzle can be designed in various ways, such as using a threaded nozzle structure. The root of the aerator nozzle has an external thread that mates with an internally threaded connector on the annular coil, allowing for detachable installation. The main body of the aerator nozzle is tubular, with an internal channel communicating with the aeration holes 13. The end of the aerator nozzle can be designed with a tapering structure, accelerating the airflow before it exits through the aeration holes 13, forming fine bubbles. The diameter of the aeration holes 13 can be selected as needed, for example, set to different specifications such as 0.5mm, 1mm, and 2mm to obtain bubbles of different sizes. Smaller hole diameters produce finer bubbles, increasing the gas-liquid contact area, but with higher resistance; larger hole diameters produce larger bubbles, with lower resistance but a smaller contact area.

[0080] The aeration nozzles and aeration holes 13 are configured in a one-to-one correspondence. Each aeration nozzle contains only one aeration hole 13, or each aeration nozzle has multiple micro-holes, but the total number of aeration holes 13 corresponds to the total number of aeration nozzles. When an aeration nozzle becomes clogged, it can be removed individually for cleaning or replacement without affecting the normal operation of other aeration nozzles, thus improving the maintainability of the system.

[0081] During system operation, CO2-containing flue gas is pressurized by the first fan 9 and enters the flue gas pipe 8. After flowing through the annular coil, it is distributed to various aeration nozzles and sprayed out from the aeration holes 13 into the wastewater. Because the aeration nozzles are evenly distributed along the annular coil, the flue gas is released simultaneously from multiple locations across the cross-section of the electrochemical treatment device 1, forming a uniformly distributed cluster of bubbles in the wastewater. The bubbles rise independently, preventing them from merging into large bubbles and dissipating too quickly, thus extending their residence time in the wastewater and improving the CO2 dissolution efficiency. Simultaneously, the uniformly distributed bubbles create a uniform disturbance to the wastewater across the entire cross-section of the electrochemical treatment device 1, promoting the uniformity of the flow field within the device, enhancing the mass transfer process of ions to the electrode surface, and thereby improving the overall efficiency of the electrochemical reaction.

[0082] Based on any of the above specific embodiments, refer to Figure 1 The flue pipe 8 is equipped with a first regulating valve 10, a pressure gauge 11 and a first flow meter 12 in sequence.

[0083] Specifically, in the flue gas pipe 8, a first regulating valve 10, a pressure gauge 11, and a first flow meter 12 are installed sequentially according to the flue gas flow direction. The first regulating valve 10 is located at the end near the flue gas inlet and is used to control the opening and closing of the flue gas pipe 8 and to regulate the flue gas flow rate. The first regulating valve 10 can be a manual regulating valve or an automatic regulating valve. For example, when a manual butterfly valve or a manual ball valve is used, the operator changes the valve opening by rotating the handle, thereby regulating the flue gas flow rate; if an electric regulating valve or a pneumatic regulating valve is used, remote or automatic regulation can be achieved through an external control signal.

[0084] Pressure gauge 11 is installed between the first regulating valve 10 and the first flow meter 12 to monitor the pressure of the flue gas delivery pipeline in the flue gas pipe 8 in real time. Pressure gauge 11 can be a Bourdon tube pressure gauge, diaphragm pressure gauge, or digital pressure gauge, etc., and its range is selected according to the flue gas pressure range. The installation position of pressure gauge 11 should be easily observable by operators to promptly detect pressure anomalies. When the reading of pressure gauge 11 rises abnormally, it may indicate a blockage in the downstream pipeline, such as a blockage in the aeration hole 13; when the reading of pressure gauge 11 drops abnormally, it may indicate insufficient upstream gas source pressure or a pipeline leak. Operators can promptly troubleshoot and handle faults based on the indication of pressure gauge 11 to ensure the normal operation of the system.

[0085] The first flow meter 12 is installed downstream of the pressure gauge 11 and is used to measure the flow rate of flue gas in the flue gas pipe 8 in real time. The first flow meter 12 can be of various types, such as a rotor flow meter, vortex flow meter, or thermal mass flow meter, and the appropriate flow meter is selected based on the flue gas composition and flow range. The reading of the first flow meter 12 directly reflects the current CO2 dosage. Operators can control the CO2 flow rate within the target range according to the processing requirements and in conjunction with the adjustment of the first regulating valve 10. For example, when it is necessary to improve the hardening effect or lower the pH value, the opening of the first regulating valve 10 can be increased to increase the CO2 dosage; when it is necessary to reduce CO2 consumption or increase the pH value, the first regulating valve 10 can be closed to reduce the CO2 dosage.

[0086] Based on any of the above specific embodiments, refer to Figure 1 The flue gas CO2 co-processing wastewater electrochemical hardening and sterilization treatment system also includes a pH sensor and a controller. The pH sensor is located in the electrochemical treatment device 1, and the controller is electrically connected to the pH sensor and the first regulating valve 10.

[0087] Specifically, a pH sensor is installed inside the electrochemical treatment unit 1, with its probe immersed in the wastewater, to monitor the pH value of the wastewater in the electrochemical treatment unit 1 in real time. The pH sensor can be installed in the middle of the electrochemical treatment unit 1 or near the outlet to obtain representative pH measurements. The pH sensor can be a glass electrode pH meter, an antimony electrode pH meter, or an ISFET solid electrode pH meter, selected according to the wastewater characteristics and measurement accuracy requirements. The pH sensor converts the detected pH value into an electrical signal and transmits it to the controller via a signal cable.

[0088] The controller can be a programmable logic controller (PLC), an embedded controller, or an industrial control computer. The controller has a preset target control range for the wastewater pH, such as a slightly acidic range of 6.2-6.8. After receiving the real-time pH signal from the pH sensor, the controller compares and calculates this real-time value with the preset target range, for example, using a PID control algorithm to calculate the control quantity that needs to be adjusted. Based on the calculation result, the controller sends a control command to the first regulating valve 10 to adjust the opening degree of the first regulating valve 10.

[0089] The first regulating valve 10 is an electrically or pneumatically operated regulating valve, capable of receiving control signals from the controller and correspondingly changing its opening degree. When the pH sensor detects that the wastewater pH is higher than the upper limit of the target range, it indicates that the wastewater is not acidic enough. The controller sends a command to the first regulating valve 10 to increase the opening degree, increasing the CO2 dosage, so that more CO2 dissolves in the water to generate carbonic acid, thus lowering the pH value. When the pH sensor detects that the wastewater pH is lower than the lower limit of the target range, it indicates that the wastewater is too acidic. The controller sends a command to the first regulating valve 10 to decrease the opening degree, reducing the CO2 dosage, so that the pH value rises back to the target range. Through this closed-loop feedback control, the system can automatically and continuously maintain the wastewater pH in the electrochemical treatment device 1 within the set weakly acidic range.

[0090] Based on any of the above specific embodiments, refer to Figure 1 The bottom of the conical sedimentation tank 5 is provided with a slag discharge pipe 71, and the slag discharge port 7 is located at the end of the slag discharge pipe 71. The slag discharge pipe 71 is provided with a second regulating valve 72, and the downstream of the second regulating valve 72 is connected to a sludge thickening tank 73.

[0091] Specifically, the bottom of the conical sedimentation tank 5 has a conical structure that is wider at the top and narrower at the bottom. A slag discharge port 7 is provided at the bottom of the cone. One end of the slag discharge pipe 71 is sealed to the slag discharge port 7, and the other end extends downstream. The slag discharge pipe 71 can be made of steel pipe, plastic pipe or composite pipe. Its diameter is determined according to the output of sediment and the discharge frequency. The direction of the slag discharge pipe 71 can be designed according to the site layout. It is usually arranged vertically downward or inclined downward to ensure that the sediment can be discharged smoothly by gravity.

[0092] A second regulating valve 72 is installed on the slag discharge pipe 71. The second regulating valve 72 can be a manual gate valve, butterfly valve, ball valve, or electric valve. The second regulating valve 72 is used to control the opening and closing of the slag discharge pipe 71 and to regulate the slag discharge flow rate. When the system is operating normally, the second regulating valve 72 is in the closed state, and the sediment accumulates at the bottom of the conical sedimentation tank 5. When the sediment accumulates to a certain amount and needs to be discharged, the operator opens the second regulating valve 72, and the sediment is discharged downstream through the slag discharge pipe 71 under the action of gravity. By adjusting the opening degree of the second regulating valve 72, the slag discharge speed can be controlled to avoid the impact of discharging a large amount of slag at once on the downstream.

[0093] Downstream of the second regulating valve 72 is a sludge thickening tank 73. The end of the sludge discharge pipe 71 extends directly into the sludge thickening tank 73 or is connected to the inlet of the sludge thickening tank 73 via a pipeline. The sludge thickening tank 73 is an independent tank structure, which can be made of reinforced concrete or steel plate, and its volume is determined according to the system's processing scale and sludge discharge volume. The main function of the sludge thickening tank 73 is to further concentrate the discharged carbonate precipitate containing a large amount of water.

[0094] When the sludge-water mixture containing sediment enters the sludge thickening tank 73, the solid particles continue to settle under gravity due to the reduced flow rate and extended residence time, accumulating at the bottom of the sludge thickening tank 73, while the supernatant gradually clarifies. The sludge thickening tank 73 is equipped with a supernatant overflow outlet or a drain outlet at the top to discharge the separated supernatant. This supernatant can be discharged directly or returned to the front end of the system to re-enter the electrochemical treatment device 1 for treatment, achieving water resource recycling. The thickened sludge accumulated at the bottom of the sludge thickening tank 73 has a lower water content and smaller volume, facilitating subsequent transportation, disposal, or resource utilization.

[0095] Based on any of the above specific embodiments, the wastewater electrochemical hardening and sterilization treatment system utilizing flue gas CO2 also includes an inlet pipe 14 and an outlet pipe 15 to form a complete wastewater treatment flow path.

[0096] Specifically, the lower side wall of the electrochemical treatment device 1 is provided with an inlet pipe 14, which is connected to a wastewater source and is used to introduce the wastewater to be treated into the electrochemical treatment device 1. A second flow meter 16 and a third regulating valve 17 can be installed on the inlet pipe 14. The second flow meter 16 is used to monitor the inlet flow rate in real time, and the third regulating valve 17 is used to adjust the inlet flow rate, so that the system can accurately control the inlet load according to the treatment requirements. The upper side wall of the electrochemical treatment device 1 is provided with an outlet pipe 15, which is equipped with a fourth regulating valve 19. The treated clean water is discharged from the system through the outlet pipe 15, which can be connected to subsequent water-using units or discharge points.

[0097] Furthermore, to address unstable flue gas supply, the system can be equipped with a backup gas source. Specifically, this includes a second fan 18, whose inlet is connected to the atmosphere or a backup CO2 gas source, and whose outlet is connected to the electrochemical treatment device 1 via a pipeline. When the first fan 9 or the main flue gas source fails, the second fan 18 can be activated to supplement the system with air or backup CO2, ensuring uninterrupted aeration within the electrochemical treatment device 1 and maintaining continuous system operation.

[0098] This application further discloses a method for treating wastewater using flue gas CO2 in conjunction with electrochemical hardening and sterilization, applied to the aforementioned system for treating wastewater using flue gas CO2 in conjunction with electrochemical hardening and sterilization. The method includes the following steps: S1. Flue gas containing CO2 is introduced into the lower part of the electrochemical treatment device 1 through the first fan 9 and flue gas pipe 8. The flue gas comes into direct contact with the wastewater through the aeration holes 13, and the CO2 dissolves in the water to generate H2CO3 and HCO3-. - Replenish CO3 in wastewater 2- , with Ca in wastewater 2+ Mg 2+ The reaction produces a carbonate precipitate; S2. An electric field is applied in the electrochemical treatment device 1 to cause an electrochemical reaction between the cathode 2 and the anode 3. The anode 3 removes Cl from the wastewater. - Oxidation to produce ClO - ; S3. By adjusting the CO2 dosage, the pH value of the wastewater in the electrochemical treatment device 1 is maintained in the weakly acidic range, so that the ClO generated at the anode 3... - With H + The generated HClO is used to sterilize the wastewater. S4. Use ultrasonic descaling device 4 to remove scale from the surface of electrodes and flow components; S5. The carbonate precipitate generated by the electrochemical process settles in the conical sedimentation tank 5 through the inclined tube clarifier 6 and is periodically discharged through the slag discharge port 7.

[0099] Specifically, in step S1, after the system starts, the first fan 9 begins operation, pressurizing the CO2-containing flue gas and sending it into the flue gas pipe 8. The flue gas flows along the flue gas pipe 8, and when it reaches the annular coil section located at the bottom of the electrochemical treatment device 1, it is released into the wastewater in the form of fine bubbles through the evenly distributed aeration holes 13. As the bubbles rise, they come into full contact with the wastewater, causing the CO2 to dissolve in the water and undergo a hydration reaction to generate carbonic acid (H2CO3). The carbonic acid further dissociates into H+. + and HCO3 - The generated HCO3 - OH generated on the surface of cathode 2 - The reaction produces CO3 2- CO3 2- Then react with Ca in the wastewater 2+ Mg 2+ The reaction produces CaCO3 and MgCO3 precipitates. This process continues, causing hardness ions in the wastewater to be continuously removed as carbonates through precipitation. The flow rate of flue gas can be controlled by the first regulating valve 10, and the pressure gauge 11 and the first flow meter 12 monitor the pipeline pressure and flow rate in real time, providing operators with reference operating parameters.

[0100] In step S2, an external power source applies a DC electric field to the cathode 2 and anode 3 within the electrochemical treatment device 1. Under the influence of the electric field, a reduction reaction occurs on the surface of the cathode 2, reducing water molecules to OH-. - And hydrogen; an oxidation reaction occurs on the surface of anode 3, releasing Cl from the wastewater. - Oxidation to produce ClO - Because cathode 2 and anode 3 adopt a parallel plate structure and are arranged at intervals, the electric field distribution is uniform, and the entire electrode surface can undergo electrochemical reactions synchronously, ensuring the ClO -The stable generation of the electric field is achieved simultaneously with the flue gas introduction in step S1. The two processes do not interfere with each other but complement each other, together forming the processing unit of the system.

[0101] In step S3, the pH value of the wastewater in the electrochemical treatment device 1 is maintained within the weakly acidic range by adjusting the CO2 dosage. Specifically, a pH sensor installed in the electrochemical treatment device 1 monitors the wastewater pH value in real time and transmits the signal to the controller. The controller compares the received real-time pH value with a preset weakly acidic range (e.g., 6.2-6.8). When the real-time pH value is higher than the upper limit, the controller sends an instruction to increase the opening of the first regulating valve 10, increasing the CO2 dosage to dissolve more CO2 and form carbonic acid, thus lowering the pH value. When the real-time pH value is lower than the lower limit, the controller sends an instruction to decrease the CO2 dosage, causing the pH value to rise back to the target range. Under these weakly acidic conditions, the ClO generated by the anode 3 in step S2... - With H in the solution + A reversible reaction occurs, producing HClO. Because the redox potential of HClO is much higher than that of ClO... - Its bactericidal ability is significantly enhanced, enabling it to efficiently kill bacteria, viruses, and other microorganisms in wastewater at lower concentrations, achieving simultaneous sterilization treatment of wastewater. This step shares the same CO2 dosing system as step S1, integrating the pH adjustment function of CO2 with the supplementation of CO3. 2- The functions are organically combined to achieve a synergistic effect of one carbon source and two benefits.

[0102] In step S4, the ultrasonic descaling device 4 starts operating according to a preset program. Multiple ultrasonic transducers, spaced apart along the electrode extension direction, simultaneously emit high-frequency ultrasonic waves onto the surfaces of the cathode 2 and anode 3. The ultrasonic waves generate cavitation effects and mechanical vibrations in the liquid medium near the electrode surface. When the cavitation bubbles burst, they generate strong shock waves and microjets, which directly act on the scale layers such as CaCO3, MgCO3, and Mg(OH)2 adhering to the electrode surface. Under repeated cavitation impacts and mechanical vibrations, the scale layers develop microcracks and gradually expand, eventually peeling off from the electrode surface. Simultaneously, due to the high hydrophobicity of the electrode material itself, the adhesion between the scale layer and the electrode surface is weak, further reducing the difficulty of descaling. The ultrasonic descaling device 4 can be set to continuous operation mode or intermittent operation mode, for example, starting ultrasonic descaling for 15 minutes every 2 hours of operation. The specific operating strategy can be adjusted according to the wastewater quality and treatment load. Through this step, the electrode surface remains clean, avoiding the increase in resistance and decrease in electrochemical reaction efficiency caused by scale accumulation, ensuring the long-term stable operation of the system.

[0103] In step S5, the carbonate precipitate generated during the electrochemical process settles naturally under gravity and enters the conical sedimentation tank 5 located below the electrochemical treatment device 1. When the wastewater containing the precipitate flows upward through the inclined tube clarifier 6, the precipitate rapidly settles within the inclined tube and slides down the tube wall to the bottom of the conical sedimentation tank 5 due to the change in hydraulic conditions within the clarifier 6. Meanwhile, the clear water overflows from the top of the inclined tube clarifier 6, achieving solid-liquid separation. Once a certain amount of precipitate accumulates at the bottom of the conical sedimentation tank 5, the operator opens the second regulating valve 72 on the sludge discharge pipe 71. The precipitate is discharged through the sludge discharge pipe 71 under gravity and enters the downstream sludge thickening tank 73 through the sludge discharge port 7. In the sludge thickening tank 73, the precipitate further settles and thickens. The supernatant can overflow or be returned to the front end of the system for reprocessing. The thickened sludge has a lower water content and smaller volume, facilitating subsequent transportation and resource utilization. Sludge removal can be carried out periodically according to the accumulation of sediment, such as once every 8 hours or once every 24 hours. The specific frequency is determined according to the amount of water to be treated and the hardness of the wastewater.

[0104] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A system for treating wastewater using flue gas CO2 in conjunction with electrochemical hardening and sterilization, characterized in that, include: An electrochemical treatment device (1) is provided with a cathode (2) and an anode (3). An ultrasonic descaling device (4) is installed inside the electrochemical treatment device (1); A conical sedimentation tank (5) is located below the electrochemical treatment device (1). An inclined tube clarifier (6) is provided inside the conical sedimentation tank (5), and a slag discharge port (7) is provided at the bottom of the conical sedimentation tank (5). A flue gas co-treatment device, wherein the flue gas co-treatment device is used to introduce CO2 into the electrochemical treatment device (1); in, The system introduces CO2 into the wastewater through the flue gas co-treatment device, causing the CO2 to react with water to produce carbonic acid and bicarbonate ions, thus replenishing the CO3 in the wastewater. 2- Ca removal by precipitation 2+ and Mg 2+ ; The CO2 dosage is adjusted by the flue gas co-treatment device to maintain the pH of the wastewater in a weakly acidic range, so that the ClO generated at the anode (3) of the electrochemical treatment device (1) can be controlled. - With H + They combine to form HClO.

2. The system for treating wastewater using flue gas CO2 in conjunction with electrochemical sterilization and disinfection as described in claim 1, characterized in that, The cathode (2) and anode (3) are plate-shaped electrodes arranged in parallel; The cathode (2) and anode (3) are made of materials that have both high conductivity and high hydrophobicity.

3. The system for treating wastewater using flue gas CO2 in conjunction with electrochemical sterilization and disinfection as described in claim 1, characterized in that, The electrochemical treatment device (1) is equipped with an electrode adjustment component, which is used to adjust the distance between the anode (3) and the cathode (2).

4. The system for treating wastewater using flue gas CO2 in conjunction with electrochemical sterilization and disinfection as described in claim 2, characterized in that, The electrode adjustment assembly includes an electrode fixing frame (101), which includes a horizontally arranged slide rail (102) and an electrode clamping block (103) slidably mounted on the slide rail (102). The cathode (2) and anode (3) are respectively fixed on the corresponding electrode clamping block (103). The electrode clamping block (103) is provided with a locking bolt (104), and the end of the locking bolt (104) abuts against the slide rail (102) to fix the electrode position.

5. The system for co-processing wastewater electrochemical sterilization and disinfection using flue gas CO2 as described in claim 1, characterized in that, The ultrasonic descaling device (4) includes a plurality of ultrasonic transducers, which are arranged at intervals along the electrode extension direction of the electrochemical treatment device (1) and the ultrasonic transducers face the surfaces of the cathode (2) and the anode (3).

6. The system for co-processing wastewater electrochemical sterilization and disinfection using flue gas CO2 as described in claim 1, characterized in that, The flue gas co-treatment device includes a flue gas pipe (8) and a first fan (9). The flue gas pipe (8) is connected to the first fan (9) and extends into the lower part of the electrochemical treatment device (1). Multiple aeration holes (13) are opened in the wastewater contact section of the flue gas pipe (8). The flue pipe (8) is sequentially equipped with a first regulating valve (10), a pressure gauge (11), and a first flow meter (12).

7. The system for treating wastewater using flue gas CO2 in conjunction with electrochemical sterilization and disinfection as described in claim 6, characterized in that, The portion of the flue gas pipe (8) located in the wastewater is in the shape of an annular coil. The portion of the flue gas pipe (8) located in the wastewater is provided with multiple aeration nozzles. The aeration nozzles are arranged in a one-to-one correspondence with the aeration holes (13), and the aeration nozzles are connected to the corresponding aeration holes (13).

8. The flue gas CO2 synergistic wastewater electrochemical sterilization and disinfection system according to claim 7, characterized in that, Also includes: pH sensor, the pH sensor being disposed within the electrochemical treatment device (1); The controller is electrically connected to the pH sensor and the first regulating valve (10).

9. The system for treating wastewater using flue gas CO2 in conjunction with electrochemical sterilization and disinfection as described in claim 1, characterized in that, The bottom of the conical sedimentation tank (5) is provided with a slag discharge pipe (71), the slag discharge port (7) is located at the end of the slag discharge pipe (71), the slag discharge pipe (71) is provided with a second regulating valve (72), and the downstream of the second regulating valve (72) is connected to a sludge thickening tank (73).

10. A method for treating wastewater using flue gas CO2 in conjunction with electrochemical sterilization and disinfection, characterized in that, The method, applied to the flue gas CO2 synergistic wastewater electrochemical hardening and sterilization treatment system as described in any one of claims 1-9, comprises the following steps: Flue gas containing CO2 is passed through a flue gas co-treatment device into the lower part of the electrochemical treatment device (1). The flue gas comes into direct contact with the wastewater, and the CO2 dissolves in the water to generate H2CO3 and HCO3-. - Replenish CO3 in wastewater 2- , with Ca in wastewater 2+ Mg 2+ The reaction produces a carbonate precipitate; An electric field is applied in the electrochemical treatment device (1) to cause an electrochemical reaction between the cathode (2) and the anode (3). The anode (3) removes Cl from the wastewater. - Oxidation to produce ClO - ; By adjusting the amount of CO2 added, the pH value of the wastewater in the electrochemical treatment device (1) is maintained in the weakly acidic range, so that the ClO generated by the anode (3) is controlled. - With H + The generated HClO is used to sterilize the wastewater. The scale on the surface of the electrodes and flow components is removed by an ultrasonic descaling device (4); The carbonate precipitate generated by the electrochemical process settles in the conical sedimentation tank (5) through the inclined tube clarifier (6) and is periodically discharged through the slag discharge port (7).

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