Control method of powder carbon backflow recycling process in sewage advanced treatment

Abstract

The invention discloses a control method of a powder carbon backflow recycling technology in advanced sewage treatment, and the control method comprises the following steps: S1, before sewage treatment, early-stage work preparation is carried out in advance, and related facility transformation and debugging are carried out on working equipment. According to the UCR tank, the discharged carbon mud flows back to the water inlet of the UCR tank again, organic matters in water can be repeatedly adsorbed until the powdered carbon reaches an adsorption saturation state, and the adsorption capacity of the powdered carbon is fully utilized on the premise that the effluent reaches the standard, so that the economic benefit is maximized; moreover, through regular operation of adding new charcoal for 4 days and refluxing charcoal mud for 6 days, the new powdered charcoal adding amount can be saved by about 60% compared with that before transformation, the time for adding powdered charcoal all year round is about 8 months, the average using amount of powdered charcoal every day is about 1 ton, about 240 tons of powdered charcoal is used all year round, and 144 tons of powdered charcoal can be saved after transformation.

Description

Technical Field

[0001] This invention relates to the field of advanced wastewater treatment technology, specifically to a control method for the process of pulverized carbon recirculation and reuse in advanced wastewater treatment. Background Technology

[0002] The upflow activated carbon adsorption pulse clarifier (UCR tank) consists of a distribution well, a carbon adsorption tank, a coagulation tank, a vacuum chamber, a water distribution system, a sludge layer zone, and an inclined tube zone. Wastewater is evenly distributed through the distribution well and then enters the adsorption tank where it rapidly mixes and contacts the powdered activated carbon. In the final rapid mixing tank, coagulants and flocculants are added. The coagulated water first enters the vacuum chamber at a stable flow rate. Under the action of vacuum, the water is pushed towards the water distribution pipe at a high speed, causing the water flow to enter the clarifier in a pulse form. The water flows upward through the carbon bed and through the inclined tube zone on the tank surface into the collection tank. The collected water flows into the next process by gravity. After the sludge layer formed in the tank reaches a certain height, it enters the sludge thickening unit for periodic discharge.

[0003] Due to the characteristics of the process design, the powdered carbon added to the system is discharged after only one adsorption in the water. Through several adsorption experiments, it was found that the adsorbed and discharged carbon sludge still has a strong adsorption capacity for organic matter in wastewater, which leads to a waste of resources. Moreover, the existing technology still has the problems of low powdered carbon utilization rate and poor economic benefits. Summary of the Invention

[0004] The purpose of this invention is to provide a control method for the recycling and reuse of powdered carbon in the deep treatment of wastewater, in order to solve the problem mentioned in the background art, where the powdered carbon added to the system is discharged after only one adsorption in the water due to the characteristics of the process design. Through several adsorption experiments, it was found that the adsorbed and discharged carbon sludge still has a strong adsorption capacity for organic matter in wastewater, which will lead to a waste of resources. Moreover, the existing technology still has the problems of low powdered carbon utilization rate and poor economic benefits.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for controlling the recirculation and reuse of powdered carbon in advanced wastewater treatment, comprising the following: S1: Before the sewage treatment work begins, preliminary work preparations are carried out in advance, and relevant facilities are modified and debugged for the working equipment. S2: Control the concentration of charcoal sludge by adjusting the intensity of the calibration pulse; S3: During operation, monitor changes in carbon sludge discharge in real time and implement precise control based on the change data; S4: Match and control the discharge and return flow of carbon sludge, and monitor the stability of the liquid level in the sludge storage tank; S5: Set the replacement cycle based on the different dosages of new charcoal powder and the concentration information of the resulting charcoal sludge; S6: Install a flow meter on the return pipeline and set a regular cleaning cycle for the return pipeline; S7: Based on the feedback monitoring information and cleaning cycle, start full-process work monitoring, and start backflushing when the return pipeline is blocked; S8: Set up special emergency response plans for the work.

[0006] Preferably, step S1 includes the following: S11: The overall process equipment for the return of pulverized carbon in advanced wastewater treatment includes, in sequence: carbon absorption tank, coagulation tank, vacuum chamber, water distribution pipe, sludge layer zone, sludge thickening unit and sludge storage tank. The equipment is equipped with return pipe, flow meter and backwash water pump, etc. A bypass return pipe is added to the sludge discharge pipe of the sludge discharge pump in the sludge storage tank. One end is connected to the main sludge discharge pipe and the other end is precisely connected to the pulverized carbon dosing point in the UCR tank to ensure that the returned carbon sludge and the newly added pulverized carbon are quickly mixed. At the same time, a flow meter is installed on the return pipe to monitor the carbon sludge return flow rate in real time. S12: Install a submersible pump in the effluent area of ​​the UCR tank, connect it to the return pipeline through a dedicated pipeline, configure a well-sealed shut-off valve to form a backwashing circuit, prevent carbon sludge from clogging the pipeline, and then debug the instruments and equipment used. S13: The feasibility of carbon sludge reuse was verified through small-scale coagulation tests. A process for the return and reuse of powdered carbon in deep wastewater treatment was implemented, and adsorption coagulation tests were conducted on powdered carbon sludge obtained from the site, proving that it still has adsorption capacity. The average test data included: sludge addition ratios of 0% (30 mg / L powdered carbon), 1%, 2%, 3%, and 4%; COD after adsorption of 18, 21, 24, 21, and 20; COD of raw water of 30; COD removal of 12, 9, 6, 9, and 10; and COD removal rates of 40.00%, 30.00%, 20.00%, 30.00%, and 33.33%. Furthermore, the test showed that as the sludge addition ratio increased, the COD removal rate of the effluent continuously increased, which is sufficient to prove that the powdered carbon sludge in the UCR tank still has an adsorption effect.

[0007] Preferably, step S2 includes the following: S21: The concentration of sludge layer in the UCR tank is captured in real time by a carbon sludge layer concentration sensor, and the uniformity of the carbon sludge layer concentration in the UCR tank is ensured by adjusting the pulse intensity, thereby ensuring that the concentration of carbon sludge discharged from the UCR is not less than 8000 mg / L. S22: If the concentration exceeds 12000mg / L, fine-tune the parameters in the opposite direction to prevent excessive disturbance of the carbon mud layer, which could cause the carbon mud to overflow through the inclined tube and affect the quality of the effluent. S23: After adjusting the pulse intensity, record the relationship between pulse parameters and carbon mud concentration daily to form a baseline parameter table, and make flexible fine adjustments based on subsequent water quality fluctuations.

[0008] Preferably, step S3 includes the following: S31: By using an ultrasonic mud-water interface meter to monitor the height of the carbon mud layer in the UCR tank, if the height exceeds the set threshold of 80%, the sludge discharge cycle is shortened. The duration of the cycle shortening is automatically adjusted according to the on-site working conditions, and the duration of the single sludge discharge is extended. The duration of the single sludge discharge extension is automatically adjusted according to the on-site working conditions, thereby quickly reducing the height of the carbon mud layer and preventing carbon mud from overflowing. S32: Monitor the carbon mud concentration in the storage tank using a carbon mud layer concentration sensor. If the concentration is below 8000 mg / L, immediately reduce the amount of sludge discharged or stop discharging sludge to prevent clean water from being discharged with the carbon mud and diluting the concentration, thus affecting the subsequent recirculation adsorption effect. S33: Based on the cooperation of the above sensors, the frequency of the sludge discharge pump in the sludge storage tank should be set reasonably to ensure that the carbon sludge return flow rate and the carbon sludge discharge rate in the UCR tank are consistent. This prevents the sludge discharge pump frequency from being too high, which would cause the liquid level in the sludge storage tank to be too low, resulting in the sludge discharge pump running dry and thus damaging the pump. If the pump frequency is too low, the liquid level in the sludge tank will be too high. In this case, the standby pump can be started to continue discharging the carbon sludge, thereby reducing the concentration of the carbon sludge and preventing it from affecting the adsorption effect of the carbon sludge return.

[0009] Preferably, step S4 includes the following: S41: Based on the real-time sludge discharge volume determined in step S3, adjust the operating frequency of the sludge discharge pump in the sludge storage tank, and monitor the return flow in real time through the electromagnetic flowmeter on the return pipeline. S42: And precisely control the amount of sludge discharged from the UCR tank. When the amount of sludge discharged is too large, it will lead to the discharge of clear water. At this time, the concentration of carbon sludge in the sludge storage tank will be reduced to prevent it from affecting the adsorption effect of carbon sludge reflux. When the amount of sludge discharged is too small, it will cause the carbon sludge layer in the UCR tank to rise. At this time, the carbon sludge will overflow through the inclined plate and affect the effluent quality of the UCR tank. S43: Set the frequency of the sludge discharge pump in the sludge storage tank reasonably to ensure that the carbon sludge return flow rate and the carbon sludge discharge rate in the UCR tank are consistent. When the frequency of the sludge discharge pump is too high, the liquid level in the sludge storage tank will be too low. At this time, the sludge discharge pump will be running dry, which will damage the sludge discharge pump. When the frequency of the sludge discharge pump is too low, the liquid level in the sludge tank will be too high. At this time, start the standby sludge discharge pump and discharge the carbon sludge to reduce the concentration of carbon sludge and prevent it from affecting the adsorption effect of carbon sludge return. S44: Set the upper and lower limits of the sludge storage tank level, which is monitored in real time by a level sensor.

[0010] Preferably, step S5 includes the following: S51: According to step S1, when the dosage of new powdered carbon is 30 mg / L, the replacement cycle is set to 4-5 days. Actual operation data shows that at this dosage, only the refluxed carbon sludge can maintain effective adsorption for 7-13 days, which is consistent with the set cycle. S52: When the dosage of new carbon powder is 50mg / L, the carbon sludge concentration increases, the adsorption saturation rate accelerates, the replacement cycle is shortened to 3-4 days, and the amount of sludge discharged during the new carbon addition stage increases, accelerating the replacement of saturated carbon sludge and avoiding the mixing of new carbon and saturated carbon sludge to reduce adsorption efficiency. S53: Real-time monitoring of COD removal rate of influent and effluent in UCR tank. If the removal rate is below 25% for two consecutive days, the removal rate shows negative growth, or the adsorption capacity of the return carbon sludge is saturated and cannot play a positive role in COD removal, replacement can be started without waiting for the cycle to end.

[0011] Preferably, step S6 includes the following: S61: The flow meter installed on the return pipeline is located close to the UCR tank pulverized carbon dosing point to ensure that the monitoring data can accurately reflect the carbon sludge return flow into the UCR tank. During operation, the flow count value is calibrated daily to check for issues such as value drift and display abnormalities, ensuring data accuracy. S62: Conduct daily inspections of the return pipeline and flow meter, check the sealing of pipeline connections and the operating status of the flow meter, record the trend of flow data changes, promptly detect potential hazards such as minor pipeline blockages and leaks, and set up a comprehensive inspection to be carried out monthly or quarterly.

[0012] Preferably, step S8 includes the following: S81: Set up the first fault response measures: monitor the liquid flow in the return pipeline in real time through the flow meter, trigger the set threshold of the flow meter, give the staff a timely warning, and stop the return operation. Then turn on the submersible pump and connect it to the return pipeline through the pipeline. Normally close the valve. After stopping the carbon sludge return, use the outlet water to flush the return pipeline to prevent carbon sludge from clogging the return pipeline. S82: Set up the second fault situation response measures: When the effluent COD is abnormal and the COD removal rate begins to rise, stop the return of powdered carbon sludge, increase the amount of new powdered carbon added, discharge saturated carbon sludge, monitor the removal rate in real time, and after the effluent meets the standards, gradually restore the return to a stable state and restart the wastewater treatment powdered carbon return and reuse work. S83: Set up a third type of fault response: If the sludge pump, submersible pump and other machinery and equipment malfunction, stop the backflow and backwashing work, switch to the backup equipment, and resume work after the main equipment has been inspected and maintained, and recalibrated and debugged. S84: Based on past operational failures, establish contingency plans for other failure scenarios to ensure the smooth operation of wastewater treatment.

[0013] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention utilizes the powdered carbon recirculation and reuse technology to return discharged carbon sludge to the inlet of the UCR tank, where it can repeatedly adsorb organic matter in the water until the powdered carbon reaches adsorption saturation. Furthermore, under the premise of meeting effluent standards, this invention fully utilizes the adsorption capacity of the powdered carbon, maximizing economic benefits. Moreover, by regularly adding new carbon for 4 days and recirculating carbon sludge for 6 days, this invention can save approximately 60% of the amount of new powdered carbon added compared to the previous method. The annual powdered carbon addition period is approximately 8 months, with an average daily usage of about 1 ton, totaling about 240 tons per year. After the modification, 144 tons of powdered carbon can be saved, thus reducing the amount of new powdered carbon added. Furthermore, by reducing the annual addition of 144 tons of new powdered carbon, 720 tons less of the 80% moisture content powdered carbon sludge is generated annually, thereby reducing the generation of carbon sludge. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the method flow of the present invention; Figure 2 This is a schematic diagram of the overall process of powdered carbon recirculation in the advanced wastewater treatment of the present invention. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0016] Please see Figures 1 to 2 This invention provides a technical solution: a control method for the powdered carbon recirculation and reuse process in advanced wastewater treatment, comprising the following: S1: Before the sewage treatment work begins, preliminary work preparations are carried out in advance, and relevant facilities are modified and debugged for the working equipment. S2: Control the concentration of charcoal sludge by adjusting the intensity of the calibration pulse; S3: During operation, monitor changes in carbon sludge discharge in real time and implement precise control based on the change data; S4: Match and control the discharge and return flow of carbon sludge, and monitor the stability of the liquid level in the sludge storage tank; S5: Set the replacement cycle based on the different dosages of new charcoal powder and the concentration information of the resulting charcoal sludge; S6: Install a flow meter on the return pipeline and set a regular cleaning cycle for the return pipeline; S7: Based on the feedback monitoring information and cleaning cycle, start full-process work monitoring, and start backflushing when the return pipeline is blocked; S8: Set up special emergency response plans for the work.

[0017] Step S1 includes the following: S11: The overall process equipment for the return of pulverized carbon in advanced wastewater treatment includes, in sequence: carbon absorption tank, coagulation tank, vacuum chamber, water distribution pipe, sludge layer zone, sludge thickening unit and sludge storage tank. The equipment is equipped with return pipe, flow meter and backwash water pump, etc. A bypass return pipe is added to the sludge discharge pipe of the sludge discharge pump in the sludge storage tank. One end is connected to the main sludge discharge pipe and the other end is precisely connected to the pulverized carbon dosing point in the UCR tank to ensure that the returned carbon sludge and the newly added pulverized carbon are quickly mixed. At the same time, a flow meter is installed on the return pipe to monitor the carbon sludge return flow rate in real time. S12: Install a submersible pump in the effluent area of ​​the UCR tank, connect it to the return pipeline through a dedicated pipeline, configure a well-sealed shut-off valve to form a backwashing circuit, prevent carbon sludge from clogging the pipeline, and then debug the instruments and equipment used. S13: The feasibility of carbon sludge reuse was verified through small-scale coagulation tests. A process for the return and reuse of powdered carbon in deep wastewater treatment was implemented, and adsorption coagulation tests were conducted on powdered carbon sludge obtained from the site, proving that it still has adsorption capacity. The average test data included: sludge addition ratios of 0% (30 mg / L powdered carbon), 1%, 2%, 3%, and 4%; COD after adsorption of 18, 21, 24, 21, and 20; COD of raw water of 30; COD removal of 12, 9, 6, 9, and 10; and COD removal rates of 40.00%, 30.00%, 20.00%, 30.00%, and 33.33%. Furthermore, the test showed that as the sludge addition ratio increased, the COD removal rate of the effluent continuously increased, which is sufficient to prove that the powdered carbon sludge in the UCR tank still has an adsorption effect.

[0018] Step S2 includes the following: S21: The concentration of sludge layer in the UCR tank is captured in real time by a carbon sludge layer concentration sensor, and the uniformity of the carbon sludge layer concentration in the UCR tank is ensured by adjusting the pulse intensity, thereby ensuring that the concentration of carbon sludge discharged from the UCR is not less than 8000 mg / L. S22: If the concentration exceeds 12000mg / L, fine-tune the parameters in the opposite direction to prevent excessive disturbance of the carbon mud layer, which could cause the carbon mud to overflow through the inclined tube and affect the quality of the effluent. S23: After adjusting the pulse intensity, record the relationship between pulse parameters and carbon mud concentration daily to form a baseline parameter table, and make flexible fine adjustments based on subsequent water quality fluctuations.

[0019] Step S3 includes the following: S31: Shorten the sludge discharge cycle: By using an ultrasonic sludge-water interface instrument to monitor the height of the carbon sludge layer in the UCR tank, if the height exceeds the set threshold of 80%, the sludge discharge cycle is shortened. The duration of the cycle shortening is automatically adjusted according to the on-site working conditions, and the duration of each sludge discharge is extended. The duration of each sludge discharge extension is automatically adjusted according to the on-site working conditions, thereby quickly reducing the height of the carbon sludge layer and preventing carbon sludge overflow. S32: Monitor the carbon mud concentration in the storage tank using a carbon mud layer concentration sensor. If the concentration is below 8000 mg / L, immediately reduce the amount of sludge discharged or stop discharging sludge to prevent clean water from being discharged with the carbon mud and diluting the concentration, thus affecting the subsequent recirculation adsorption effect. S33: Based on the cooperation of the above sensors, the frequency of the sludge discharge pump in the sludge storage tank should be set reasonably to ensure that the carbon sludge return flow rate and the carbon sludge discharge rate in the UCR tank are consistent. This prevents the sludge discharge pump frequency from being too high, which would cause the liquid level in the sludge storage tank to be too low, resulting in the sludge discharge pump running dry and thus damaging the pump. If the pump frequency is too low, the liquid level in the sludge tank will be too high. In this case, the standby pump can be started to continue discharging the carbon sludge, thereby reducing the concentration of the carbon sludge and preventing it from affecting the adsorption effect of the carbon sludge return.

[0020] Step S4 includes the following: S41: Based on the real-time sludge discharge volume determined in step S3, adjust the operating frequency of the sludge discharge pump in the sludge storage tank, and monitor the return flow in real time through the electromagnetic flowmeter on the return pipeline. S42: And precisely control the amount of sludge discharged from the UCR tank. When the amount of sludge discharged is too large, it will lead to the discharge of clear water. At this time, the concentration of carbon sludge in the sludge storage tank will be reduced to prevent it from affecting the adsorption effect of carbon sludge reflux. When the amount of sludge discharged is too small, it will cause the carbon sludge layer in the UCR tank to rise. At this time, the carbon sludge will overflow through the inclined plate and affect the effluent quality of the UCR tank. S43: Set the frequency of the sludge discharge pump in the sludge storage tank reasonably to ensure that the carbon sludge return flow rate and the carbon sludge discharge rate in the UCR tank are consistent. When the frequency of the sludge discharge pump is too high, the liquid level in the sludge storage tank will be too low. At this time, the sludge discharge pump will be running dry, which will damage the sludge discharge pump. When the frequency of the sludge discharge pump is too low, the liquid level in the sludge tank will be too high. At this time, start the standby sludge discharge pump and discharge the carbon sludge to reduce the concentration of carbon sludge and prevent it from affecting the adsorption effect of carbon sludge return. S44: Set the upper and lower limits of the sludge storage tank level, which is monitored in real time by a level sensor.

[0021] Step S5 includes the following: S51: According to step S1, when the dosage of new powdered carbon is 30 mg / L, the replacement cycle is set to 4-5 days. Actual operation data shows that at this dosage, only the refluxed carbon sludge can maintain effective adsorption for 7-13 days, which is consistent with the set cycle. S52: When the dosage of new carbon powder is 50mg / L, the carbon sludge concentration increases, the adsorption saturation rate accelerates, the replacement cycle is shortened to 3-4 days, and the amount of sludge discharged during the new carbon addition stage increases, accelerating the replacement of saturated carbon sludge and avoiding the mixing of new carbon and saturated carbon sludge to reduce adsorption efficiency. S53: Real-time monitoring of COD removal rate of influent and effluent in UCR tank. If the removal rate is below 25% for two consecutive days, the removal rate shows negative growth, or the adsorption capacity of the return carbon sludge is saturated and cannot play a positive role in COD removal, replacement can be started without waiting for the cycle to end.

[0022] Step S6 includes the following: S61: The flow meter installed on the return pipeline is located close to the UCR tank pulverized carbon dosing point to ensure that the monitoring data can accurately reflect the carbon sludge return flow into the UCR tank. During operation, the flow count value is calibrated daily to check for issues such as value drift and display abnormalities, ensuring data accuracy. S62: Conduct daily inspections of the return pipeline and flow meter, check the sealing of pipeline connections and the operating status of the flow meter, record the trend of flow data changes, promptly detect potential hazards such as minor pipeline blockages and leaks, and set up a comprehensive inspection to be carried out monthly or quarterly.

[0023] Step S7 includes the following: S71: Real-time monitoring of key parameters such as the amount of new powdered carbon added, carbon sludge return flow / discharge, carbon sludge concentration in the UCR tank, sludge storage tank level, influent and effluent COD and removal rate, etc., and recording data daily to form trend curves, summarizing and analyzing weekly, optimizing process parameters, judging pipeline patency by changes in flow count values, if the flow rate continues to decrease and the sludge discharge pump is ruled out as faulty, it is determined that the pipeline is blocked, and the backwashing procedure is immediately started; S72: It automatically starts after each stop of carbon sludge reflux, opens the valve, starts the UCR tank effluent submersible pump to backwash the pipeline, closes the valve after rinsing, lets stand for 5 minutes to drain the residual water, and then resumes reflux. S73: If the pipeline is blocked, start enhanced backflushing and extend the flushing time to 40 minutes. If the flow rate does not recover after flushing, intervene with manual cleaning or maintenance. Combine with the cleaning cycle determined in step S6, perform a full enhanced backflushing once a week for 30 minutes to thoroughly remove stubborn carbon sludge and take measures to prevent blockage.

[0024] Step S8 includes the following: S81: Set up the first fault response measures: monitor the liquid flow in the return pipeline in real time through the flow meter, trigger the set threshold of the flow meter, give the staff a timely warning, and stop the return operation. Then turn on the submersible pump and connect it to the return pipeline through the pipeline. Normally close the valve. After stopping the carbon sludge return, use the outlet water to flush the return pipeline to prevent carbon sludge from clogging the return pipeline. S82: Set up the second fault situation response measures: When the effluent COD is abnormal and the COD removal rate begins to rise, stop the return of powdered carbon sludge, increase the amount of new powdered carbon added, discharge saturated carbon sludge, monitor the removal rate in real time, and after the effluent meets the standards, gradually restore the return to a stable state and restart the wastewater treatment powdered carbon return and reuse work. S83: Set up a third type of fault response: If the sludge pump, submersible pump and other machinery and equipment malfunction, stop the backflow and backwashing work, switch to the backup equipment, and resume work after the main equipment has been inspected and maintained, and recalibrated and debugged. S84: Based on past operational failures, establish contingency plans for other failure scenarios to ensure the smooth operation of wastewater treatment.

[0025] Specifically, when using this invention, step S1: the overall process equipment for the return of pulverized carbon in deep wastewater treatment sequentially includes: a carbon absorption tank, a coagulation tank, a vacuum chamber, a water distribution pipe, a sludge layer zone, a sludge thickening unit, and a sludge storage tank. The equipment is equipped with return pipes, flow meters, and backwash pumps. A bypass return pipe is added to the sludge discharge pipe of the sludge discharge pump in the sludge storage tank, with one end connected to the main sludge discharge pipe and the other end precisely connected to the pulverized carbon addition point in the UCR tank, ensuring rapid mixing of the returned carbon sludge and newly added pulverized carbon. A flow meter is also installed on the return pipe for real-time monitoring of the carbon sludge return flow rate. A submersible pump is installed in the effluent area of ​​the UCR tank, connected to the return pipe via a dedicated pipeline, and equipped with a well-sealed shut-off valve to form a backwash loop, preventing carbon sludge blockage of the pipeline. Then, the equipment is debugged. Through coagulation... The feasibility of carbon sludge reuse was verified by implementing a process for the return and reuse of powdered carbon in advanced wastewater treatment. Adsorption and coagulation tests were conducted on powdered carbon sludge obtained from the site, demonstrating its adsorption capacity. The average test data included: sludge addition ratios of 0% (30 mg / L powdered carbon), 1%, 2%, 3%, and 4%; COD after adsorption of 18, 21, 24, 21, and 20; COD of raw water of 30; COD removal of 12, 9, 6, 9, and 10; and COD removal rates of 40.00%, 30.00%, 20.00%, 30.00%, and 33.33%. Furthermore, the experiment showed that the COD removal rate of the effluent increased with the increase of the sludge addition ratio, sufficiently proving that the powdered carbon sludge in the UCR tank still has an adsorption effect. During the on-site modification phase (May 2025 to June 2025), the following time periods refer to the actual operation time: On-site modification: Install return pipes, flow meters and backwash water pumps on-site, and conduct on-site commissioning.

[0026] On-site operation and commissioning phase (June 2025 to August 2025) (1) First stage (June 23 - July 11): Add new carbon: 30 mg / L, carbon sludge return flow rate: about 40 m3 / h, and discharge carbon sludge. In the early stage, it is clear water. By adjusting the sludge discharge time and vacuum extraction ratio, the sludge return started on June 26.

[0027] Test date UCR influent COD UCR Effluent COD COD removal COD removal rate (mg / L) (mg / L) (mg / L) 2025 / 6 / 23 20.82 16.05 4.77 22.89% 2025 / 6 / 24 21.96 16.41 5.55 25.27% 2025 / 6 / 25 21.53 16.90 4.63 21.49% 2025 / 6 / 26 22.01 17.67 4.34 19.71% 2025 / 6 / 27 21.15 18.66 2.50 11.80% 2025 / 6 / 28 22.06 18.39 3.67 16.65% 2025 / 6 / 29 21.26 18.07 3.19 14.99% 2025 / 6 / 30 20.98 16.55 4.43 21.10% 2025 / 7 / 1 20.76 17.12 3.64 17.53% 2025 / 7 / 2 23.56 14.58 8.99 38.14% 2025 / 7 / 3 21.09 12.87 8.22 38.99% 2025 / 7 / 4 18.47 12.85 5.62 30.42% 2025 / 7 / 5 18.84 13.59 5.25 27.89% 2025 / 7 / 6 20.21 14.02 6.19 30.64% 2025 / 7 / 7 20.09 14.97 5.12 25.49% 2025 / 7 / 8 20.23 18.53 1.70 8.39% 2025 / 7 / 9 20.21 23.21 -3.00 -14.82% 2025 / 7 / 10 20.38 23.40 -3.02 -14.82% 2025 / 7 / 11 19.30 23.40 -4.10 -21.23% Initially, because the returned water was clean water, the COD removal rate initially decreased. Later, as the concentration of the returned sludge increased, the COD removal rate began to rise, reaching its peak on July 2-3. Subsequently, as the adsorption capacity of the returned powdered activated carbon sludge gradually became saturated, it could no longer play a positive role in COD removal, so the COD removal efficiency began to decrease, and by July 9, it had completely lost its adsorption effect, even leading to a decrease in COD adsorption effect from July 9 to 11.

[0028] (2) Second stage (July 12-17): Add new powdered carbon (30 mg / L) and stop the return of powdered carbon sludge.

[0029] Test date UCR influent COD UCR Effluent COD COD removal COD removal rate (mg / L) (mg / L) (mg / L) 2025 / 7 / 12 19.98 23.06 -3.08 -15.40% 2025 / 7 / 13 19.22 22.86 -3.64 -18.95% 2025 / 7 / 14 20.27 22.70 -2.43 -11.98% 2025 / 7 / 15 19.62 17.13 2.49 12.68% 2025 / 7 / 16 20.89 17.62 3.27 15.66% 2025 / 7 / 17 21.18 15.57 5.61 26.49% After stopping the return of powdered activated carbon sludge, the COD removal effect begins to recover over time, and it takes about 6 days to recover to the state of only adding new activated carbon (30 mg / L).

[0030] (3) Third stage (July 18 - August 4): Add new carbon: 30 mg / L, carbon sludge return flow rate: about 30 m3 / h, stop the discharge of carbon sludge.

[0031] Test date UCR influent COD UCR Effluent COD COD removal COD removal rate (mg / L) (mg / L) (mg / L) 7 / 18 20.98 15.78 5.20 24.79% 7 / 19 20.64 15.86 4.78 23.14% 7 / 20 19.90 15.35 4.55 22.86% 7 / 21 18.19 14.56 3.63 19.98% 7 / 22 19.09 16.25 2.84 14.88% 7 / 23 22.49 19.94 2.55 11.33% 7 / 24 23.05 20.42 2.63 11.39% 7 / 25 24.70 20.68 4.02 16.27% 7 / 26 25.61 20.76 4.85 18.92% 7 / 27 26.63 20.37 6.26 23.52% 7 / 28 25.87 19.37 6.50 25.11% 7 / 29 25.44 17.38 8.06 31.67% 7 / 30 24.29 16.00 8.29 34.13% 7 / 31 24.64 17.44 7.20 29.23% 8 / 1 24.79 17.12 7.67 30.94% 8 / 2 22.73 16.55 6.18 27.18% 8 / 3 22.35 17.00 5.35 23.93% 8 / 4 20.80 15.01 5.79 27.84% When the sludge recirculation with activated carbon was restarted, the recirculated liquid was initially clear water. It was not until the evening of the 20th that the recirculated liquid began to turn into activated carbon sludge. Initially, because the recirculated liquid was clear water and the concentration of activated carbon sludge gradually increased, the COD removal efficiency initially decreased. Later, as the concentration of activated carbon sludge increased, the COD removal rate began to rise, reaching its peak on July 30th. Subsequently, as the adsorption capacity of the recirculated activated carbon sludge gradually became saturated, the COD removal efficiency began to decrease. However, compared with the discharged sludge, there was no sharp drop in COD removal efficiency. On August 4th, the sludge recirculation with activated carbon was stopped, and the COD removal efficiency immediately rebounded.

[0032] Phase 4 (August 4 - August 10): The returned pulverized carbon sludge has no adsorption effect, so stop the return, add new carbon: 30 mg / L, discharge the pulverized carbon sludge, and renew the pulverized carbon sludge.

[0033] Test date UCR influent COD UCR Effluent COD COD removal COD removal rate (mg / L) (mg / L) (mg / L) 2025 / 8 / 5 19.7 17.84 1.86 9.44% 2025 / 8 / 6 21.73 16.7 5.03 23.15% 2025 / 8 / 7 22.7 13.71 8.99 39.60% 2025 / 8 / 8 21.22 13.72 7.5 35.34% 2025 / 8 / 9 19.77 13.17 6.6 33.38% 2025 / 8 / 10 19.15 11.82 7.33 38.28% After stopping the return of powdered activated carbon sludge, the COD removal efficiency begins to recover over time, and it takes about 3 days to return to the state when only 30 mg / L of new activated carbon is added.

[0034] Practical application phase (August 2025 to November 2025) (1) August 11-23: Stop adding new powdered carbon (30 mg / L) and external sludge, and only return powdered carbon sludge (return flow rate: about 30 m3 / h).

[0035] Test date UCR influent COD UCR Effluent COD COD removal COD removal rate (mg / L) (mg / L) (mg / L) 2025 / 8 / 11 18.22 11.64 6.58 36.11% 2025 / 8 / 12 19.58 13.08 6.5 33.20% 2025 / 8 / 13 20.71 11.58 9.13 44.08% 2025 / 8 / 14 22.06 13 9.06 41.07% 2025 / 8 / 15 22.21 15.15 7.06 31.79% 2025 / 8 / 16 22.4 15.8 6.6 29.46% 2025 / 8 / 17 20.7 13.89 6.81 32.90% 2025 / 8 / 18 21.27 13.58 7.69 36.15% 2025 / 8 / 19 20.35 14.01 6.34 31.15% 2025 / 8 / 20 18.45 12.55 5.9 31.98% 2025 / 8 / 21 18.37 11.69 6.68 36.36% 2025 / 8 / 22 20.36 13.27 7.09 34.82% 2025 / 8 / 23 19.7 14.63 5.07 25.74% After the reflux of the powdered carbon sludge was started, its COD removal rate remained at 34.92%. On August 23, the COD adsorption effect decreased and remained for about 13 days.

[0036] (2) August 24 - August 31: Resume adding new carbon (30 mg / L), discharge the charcoal sludge, update the charcoal sludge layer, and stop the charcoal sludge return.

[0037] Test date UCR influent COD UCR Effluent COD COD removal COD removal rate (mg / L) (mg / L) (mg / L) 2025 / 8 / 24 20.98 15.11 5.87 27.98% 2025 / 8 / 25 20.86 14.23 6.63 31.78% 2025 / 8 / 26 19.61 12.94 6.67 34.01% 2025 / 8 / 27 18.74 12.48 6.26 33.40% 2025 / 8 / 28 19.41 11.46 7.95 40.96% 2025 / 8 / 29 16.67 10.94 5.73 34.37% 2025 / 8 / 30 18.48 12 6.48 35.06% 2025 / 8 / 31 18.63 12.69 5.94 31.88% When new powdered activated carbon was added again, the COD adsorption effect gradually increased and stabilized in about 3 days.

[0038] (3) October 9-October 15: Stop adding new powdered carbon (30 mg / L) and external sludge, and only return the powdered carbon sludge (return flow rate: about 30 m3 / h).

[0039] Test date UCR influent COD UCR Effluent COD COD removal COD removal rate (mg / L) (mg / L) (mg / L) 2025 / 10 / 9 18.34 12.75 5.59 30.48% 2025 / 10 / 10 14.89 9.27 5.62 37.74% 2025 / 10 / 11 14.35 9.48 4.87 33.94% 2025 / 10 / 12 17.18 10.92 6.26 36.44% 2025 / 10 / 13 20.03 13.75 6.28 31.35% 2025 / 10 / 14 21.18 15.78 5.4 25.50% 2025 / 10 / 15 20.79 16.58 4.21 20.25% After the reflux of powdered carbon sludge began, the average COD removal rate was 30.81%. On October 13, the COD adsorption effect decreased and remained so for about 7 days.

[0040] (4) October 16-22: Resume adding new carbon (30 mg / L), discharge the charcoal sludge, replace the charcoal sludge layer, and stop the charcoal sludge return.

[0041] Test date UCR influent COD UCR Effluent COD COD removal COD removal rate (mg / L) (mg / L) (mg / L) 2025 / 10 / 16 22.56 17.13 5.43 24.07% 2025 / 10 / 17 22.65 15.48 7.17 31.66% 2025 / 10 / 18 21.59 15.29 6.3 29.18% 2025 / 10 / 19 22.08 14.86 7.22 32.70% 2025 / 10 / 20 21.53 14.68 6.85 31.82% 2025 / 10 / 21 24.52 14.55 9.97 40.66% 2025 / 10 / 22 23.82 14.29 9.53 40.01% When the new powdered activated carbon was added again, the COD adsorption effect gradually increased and reached a stable level in about 4 days. Step S2: The sludge concentration in the UCR tank is captured in real time by a sludge layer concentration sensor. The pulse intensity is adjusted to ensure the uniformity of the sludge concentration in the UCR tank, thereby ensuring that the sludge concentration of the UCR discharge is not less than 8000 mg / L. If the concentration exceeds 12000 mg / L, the parameters are finely adjusted in the opposite direction to prevent excessive disturbance of the sludge layer from causing sludge to overflow through the inclined tube and affect the effluent quality. After the pulse intensity is adjusted, the relationship between the pulse parameters and the sludge concentration is recorded daily to form a baseline parameter table, which can be flexibly fine-tuned in combination with subsequent water quality fluctuations. Step S3: Monitor the height of the carbon sludge layer in the UCR tank using an ultrasonic sludge-water interface meter. If the height exceeds the set threshold of 80%, shorten the sludge discharge cycle. The shortening period is automatically adjusted based on the on-site working conditions. Also, extend the single sludge discharge time, which is also automatically adjusted based on the on-site working conditions. This quickly reduces the carbon sludge layer height and prevents carbon sludge overflow. Monitor the carbon sludge concentration in the storage tank using a carbon sludge layer concentration sensor. If the concentration is below 8000 mg / L, immediately reduce the sludge discharge rate or suspend sludge discharge. To prevent the concentration of clean water from being diluted with the carbon sludge during discharge, which would affect the subsequent recirculation adsorption effect, and based on the cooperation of the above sensors, the frequency of the sludge discharge pump in the sludge storage tank should be reasonably set to ensure that the carbon sludge return flow rate and the carbon sludge discharge rate in the UCR tank are consistent. This prevents the sludge discharge pump frequency from being too high, which would cause the liquid level in the sludge storage tank to be too low, resulting in the sludge discharge pump running dry and thus damaging the pump. On the other hand, if the pump frequency is too low, the liquid level in the sludge tank will be too high. In this case, the standby pump can be started to continue to discharge the carbon sludge, thereby reducing the concentration of the carbon sludge and preventing it from affecting the adsorption effect of the carbon sludge recirculation. Step S4: Based on the real-time sludge discharge rate determined in Step S3, adjust the operating frequency of the sludge discharge pump in the sludge storage tank. Monitor the return flow rate in real time using an electromagnetic flowmeter on the return pipeline and precisely control the sludge discharge rate in the UCR tank. If the sludge discharge rate is too high, it will result in the discharge of clear water. In this case, reduce the carbon sludge concentration in the sludge storage tank to prevent affecting the adsorption effect of the carbon sludge return. If the sludge discharge rate is too low, the carbon sludge layer in the UCR tank will rise. In this case, the carbon sludge will overflow through the inclined plate, affecting the effluent quality of the UCR tank. Set the frequency of the sludge discharge pump in the sludge storage tank reasonably to ensure that the carbon sludge return flow rate and the carbon sludge discharge rate in the UCR tank are consistent. If the frequency of the sludge discharge pump is too high, it will result in the liquid level in the sludge storage tank being too low. In this case, the sludge discharge pump will be started and the carbon sludge will be discharged to reduce the carbon sludge concentration and prevent affecting the adsorption effect of the carbon sludge return. Set the upper and lower limits of the liquid level in the sludge storage tank and monitor them in real time using a liquid level sensor. Step S5: Based on Step S1, when the dosage of new powdered activated carbon is 30 mg / L, the replacement cycle is set to 4-5 days. Actual operation data shows that at this dosage, only the recirculated activated carbon sludge can maintain effective adsorption for 7-13 days, which is consistent with the set cycle. When the dosage of new powdered activated carbon is 50 mg / L, the activated carbon sludge concentration increases, the adsorption saturation rate accelerates, and the replacement cycle is shortened to 3-4 days. Simultaneously, the amount of sludge discharged during the new activated carbon addition stage is increased to accelerate the replacement of saturated activated carbon sludge and avoid the mixing of new activated carbon and saturated activated carbon sludge, which reduces adsorption efficiency. Real-time monitoring of the COD removal rate of the UCR tank influent and effluent is conducted. If the removal rate is below 25% for two consecutive days, the removal rate shows negative growth, or the recirculated activated carbon sludge adsorption capacity is saturated and cannot play a positive role in COD removal, replacement can be initiated without waiting for the cycle to end. Step S6: Install the flow meter on the return pipeline, with the installation position close to the side of the UCR tank pulverized carbon addition point, to ensure that the monitoring data can accurately reflect the carbon sludge return flow into the UCR tank. During operation, calibrate the flow count value daily, check for issues such as value drift and display abnormalities, and ensure data accuracy. Inspect the return pipeline and flow meter daily, check the sealing of pipeline connections and the operating status of the flow meter, record the flow data change trend, promptly detect potential hazards such as minor pipeline blockages and leaks, and set up a comprehensive inspection to be carried out monthly or quarterly. Step S7: Monitor key parameters in real time, including the amount of new activated carbon added, carbon sludge return flow / discharge, carbon sludge concentration in the UCR tank, sludge storage tank level, influent and effluent COD and removal rate. Record data daily and generate trend curves, summarize and analyze weekly, optimize process parameters, and determine pipeline patency by changes in flow count. If the flow rate continues to decrease and the sludge discharge pump is ruled out as faulty, the pipeline is considered blocked. In this case, immediately initiate the backwashing procedure, which will automatically start after each carbon sludge return is stopped, open the valve, and start the UCR tank effluent submersible pump to backwash the pipeline. After flushing, close the valve, let it stand for 5 minutes to drain residual water, and then resume return flow. If the pipeline is blocked, initiate enhanced backwashing, extending the flushing time to 40 minutes. If the flow rate does not recover after flushing, intervene with manual cleaning or maintenance, and combine with the cleaning cycle determined in Step S6, conduct a comprehensive enhanced backwash once a week for 30 minutes to thoroughly remove stubborn carbon sludge, implement blockage prevention measures, and set up a response plan for the first fault scenario. Measures: The flow rate in the return pipeline is monitored in real time using a flow meter. The flow meter's set threshold is triggered to provide timely warnings to staff and stop the return process. A submersible pump is then activated and connected to the return pipeline. Valves are normally closed. After stopping the carbon sludge return, the return pipeline is flushed with effluent to prevent blockage. A second contingency plan is in place: When the effluent COD is abnormal and the COD removal rate begins to rise, the return of powdered carbon sludge is stopped, the dosage of new powdered carbon is increased, saturated carbon sludge is discharged, and the removal rate is monitored in real time. Once the effluent meets standards, the return process is gradually restored to a stable state, and the wastewater treatment powdered carbon return and reuse operation is restarted. A third contingency plan is in place: If the sludge pump, submersible pump, or other equipment malfunctions, the return and backwashing operations are stopped, and backup equipment is used. After the main equipment is repaired and maintained, it is recalibrated and tested before resuming operation. Based on past failure scenarios, other contingency plans are established to ensure wastewater treatment operations.

[0042] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A control method for the process of powdered carbon recirculation and reuse in advanced wastewater treatment, characterized in that, Includes the following: S1: Before the sewage treatment work begins, preliminary work preparations are carried out in advance, and relevant facilities are modified and debugged for the working equipment. S2: Control the concentration of charcoal sludge by adjusting the intensity of the calibration pulse; S3: During operation, monitor changes in carbon sludge discharge in real time and implement precise control based on the change data; S4: Match and control the discharge and return flow of carbon sludge, and monitor the stability of the liquid level in the sludge storage tank; S5: Set the replacement cycle based on the different dosages of new charcoal powder and the concentration information of the resulting charcoal sludge; S6: Install a flow meter on the return pipeline and set a regular cleaning cycle for the return pipeline; S7: Based on the feedback monitoring information and cleaning cycle, start full-process work monitoring, and start backflushing when the return pipeline is blocked; S8: Set up special emergency response plans for the work.

2. The control method for the powdered carbon recirculation and reuse process in advanced wastewater treatment according to claim 1, characterized in that: Step S1 includes the following: S11: The overall process equipment for the return of pulverized carbon in advanced wastewater treatment includes, in sequence: carbon absorption tank, coagulation tank, vacuum chamber, water distribution pipe, sludge layer zone, sludge thickening unit and sludge storage tank. The equipment is equipped with return pipe, flow meter and backwash water pump, etc. A bypass return pipe is added to the sludge discharge pipe of the sludge discharge pump in the sludge storage tank. One end is connected to the main sludge discharge pipe and the other end is precisely connected to the pulverized carbon dosing point in the UCR tank to ensure that the returned carbon sludge and the newly added pulverized carbon are quickly mixed. At the same time, a flow meter is installed on the return pipe to monitor the carbon sludge return flow rate in real time. S12: Install a submersible pump in the effluent area of ​​the UCR tank, connect it to the return pipeline through a dedicated pipeline, configure a well-sealed shut-off valve to form a backwashing circuit, prevent carbon sludge from clogging the pipeline, and then debug the instruments and equipment used. S13: The feasibility of carbon sludge reuse was verified through small-scale coagulation tests. A process for the return and reuse of powdered carbon in deep wastewater treatment was implemented, and adsorption coagulation tests were conducted on powdered carbon sludge obtained from the site, proving that it still has adsorption capacity. The average test data included: sludge addition ratios of 0% (30 mg / L powdered carbon), 1%, 2%, 3%, and 4%; COD after adsorption of 18, 21, 24, 21, and 20; COD of raw water of 30; COD removal of 12, 9, 6, 9, and 10; and COD removal rates of 40.00%, 30.00%, 20.00%, 30.00%, and 33.33%. Furthermore, the test showed that as the sludge addition ratio increased, the COD removal rate of the effluent continuously increased, which is sufficient to prove that the powdered carbon sludge in the UCR tank still has an adsorption effect.

3. The control method for the powdered carbon recirculation and reuse process in advanced wastewater treatment according to claim 1, characterized in that: Step S2 includes the following: S21: The concentration of sludge layer in the UCR tank is captured in real time by a carbon sludge layer concentration sensor, and the uniformity of the carbon sludge layer concentration in the UCR tank is ensured by adjusting the pulse intensity, thereby ensuring that the concentration of carbon sludge discharged from the UCR is not less than 8000 mg / L. S22: If the concentration exceeds 12000mg / L, fine-tune the parameters in the opposite direction to prevent excessive disturbance of the carbon mud layer, which could cause the carbon mud to overflow through the inclined tube and affect the quality of the effluent. S23: After adjusting the pulse intensity, record the relationship between pulse parameters and carbon mud concentration daily to form a baseline parameter table, and make flexible fine adjustments based on subsequent water quality fluctuations.

4. The control method for the powdered carbon recirculation and reuse process in advanced wastewater treatment according to claim 1, characterized in that: Step S3 includes the following: S31: By using an ultrasonic mud-water interface meter to monitor the height of the carbon mud layer in the UCR tank, if the height exceeds the set threshold of 80%, the sludge discharge cycle is shortened. The duration of the cycle shortening is automatically adjusted according to the on-site working conditions, and the duration of the single sludge discharge is extended. The duration of the single sludge discharge extension is automatically adjusted according to the on-site working conditions, thereby quickly reducing the height of the carbon mud layer and preventing carbon mud from overflowing. S32: Monitor the carbon mud concentration in the storage tank using a carbon mud layer concentration sensor. If the concentration is below 8000 mg / L, immediately reduce the amount of sludge discharged or stop discharging sludge to prevent clean water from being discharged with the carbon mud and diluting the concentration, thus affecting the subsequent recirculation adsorption effect. S33: Based on the cooperation of the above sensors, the frequency of the sludge discharge pump in the sludge storage tank should be set reasonably to ensure that the carbon sludge return flow rate and the carbon sludge discharge rate in the UCR tank are consistent. This prevents the sludge discharge pump frequency from being too high, which would cause the liquid level in the sludge storage tank to be too low, resulting in the sludge discharge pump running dry and thus damaging the pump. If the pump frequency is too low, the liquid level in the sludge tank will be too high. In this case, the standby pump can be started to continue discharging the carbon sludge, thereby reducing the concentration of the carbon sludge and preventing it from affecting the adsorption effect of the carbon sludge return.

5. The control method for the powdered carbon recirculation and reuse process in advanced wastewater treatment according to claim 1, characterized in that: Step S4 includes the following: S41: Based on the real-time sludge discharge volume determined in step S3, adjust the operating frequency of the sludge discharge pump in the sludge storage tank, and monitor the return flow in real time through the electromagnetic flowmeter on the return pipeline. S42: And precisely control the amount of sludge discharged from the UCR tank. When the amount of sludge discharged is too large, it will lead to the discharge of clear water. At this time, the concentration of carbon sludge in the sludge storage tank will be reduced to prevent it from affecting the adsorption effect of carbon sludge reflux. When the amount of sludge discharged is too small, it will cause the carbon sludge layer in the UCR tank to rise. At this time, the carbon sludge will overflow through the inclined plate and affect the effluent quality of the UCR tank. S43: Set the frequency of the sludge discharge pump in the sludge storage tank reasonably to ensure that the carbon sludge return flow rate and the carbon sludge discharge rate in the UCR tank are consistent. When the frequency of the sludge discharge pump is too high, the liquid level in the sludge storage tank will be too low. At this time, the sludge discharge pump will be running dry, which will damage the sludge discharge pump. When the frequency of the sludge discharge pump is too low, the liquid level in the sludge tank will be too high. At this time, start the standby sludge discharge pump and discharge the carbon sludge to reduce the concentration of carbon sludge and prevent it from affecting the adsorption effect of carbon sludge return. S44: Set the upper and lower limits of the sludge storage tank level, which is monitored in real time by a level sensor.

6. The control method for the powdered carbon recirculation and reuse process in advanced wastewater treatment according to claim 1, characterized in that: Step S5 includes the following: S51: According to step S1, when the dosage of new powdered carbon is 30 mg / L, the replacement cycle is set to 4-5 days. Actual operation data shows that at this dosage, only the refluxed carbon sludge can maintain effective adsorption for 7-13 days, which is consistent with the set cycle. S52: When the dosage of new carbon powder is 50mg / L, the carbon sludge concentration increases, the adsorption saturation rate accelerates, the replacement cycle is shortened to 3-4 days, and the amount of sludge discharged during the new carbon addition stage increases, accelerating the replacement of saturated carbon sludge and avoiding the mixing of new carbon and saturated carbon sludge to reduce adsorption efficiency. S53: Real-time monitoring of COD removal rate of influent and effluent in UCR tank. If the removal rate is below 25% for two consecutive days, the removal rate shows negative growth, or the adsorption capacity of the return carbon sludge is saturated and cannot play a positive role in COD removal, replacement can be started without waiting for the cycle to end.

7. The control method for the powdered carbon recirculation and reuse process in advanced wastewater treatment according to claim 1, characterized in that: Step S6 includes the following: S61: The flow meter installed on the return pipeline is located close to the UCR tank pulverized carbon dosing point to ensure that the monitoring data can accurately reflect the carbon sludge return flow into the UCR tank. During operation, the flow count value is calibrated daily to check for issues such as value drift and display abnormalities, ensuring data accuracy. S62: Conduct daily inspections of the return pipeline and flow meter, check the sealing of pipeline connections and the operating status of the flow meter, record the trend of flow data changes, promptly detect potential hazards such as minor pipeline blockages and leaks, and set up a comprehensive inspection to be carried out monthly or quarterly.

8. The control method for the powdered carbon recirculation and reuse process in advanced wastewater treatment according to claim 1, characterized in that: Step S7 includes the following: S71: Real-time monitoring of key parameters such as the amount of new powdered carbon added, carbon sludge return flow / discharge, carbon sludge concentration in the UCR tank, sludge storage tank level, influent and effluent COD and removal rate, etc., and recording data daily to form trend curves, summarizing and analyzing weekly, optimizing process parameters, judging pipeline patency by changes in flow count values, if the flow rate continues to decrease and the sludge discharge pump is ruled out as faulty, it is determined that the pipeline is blocked, and the backwashing procedure is immediately started; S72: It automatically starts after each stop of carbon sludge reflux, opens the valve, starts the UCR tank effluent submersible pump to backwash the pipeline, closes the valve after rinsing, lets stand for 5 minutes to drain the residual water, and then resumes reflux. S73: If the pipeline is blocked, start enhanced backflushing and extend the flushing time to 40 minutes. If the flow rate does not recover after flushing, intervene with manual cleaning or maintenance. Combine with the cleaning cycle determined in step S6, perform a full enhanced backflushing once a week for 30 minutes to thoroughly remove stubborn carbon sludge and take measures to prevent blockage.

9. The control method for the powdered carbon recirculation and reuse process in advanced wastewater treatment according to claim 1, characterized in that: Step S8 includes the following: S81: Set up the first fault response measures: monitor the liquid flow in the return pipeline in real time through the flow meter, trigger the set threshold of the flow meter, give the staff a timely warning, and stop the return operation. Then turn on the submersible pump and connect it to the return pipeline through the pipeline. Normally close the valve. After stopping the carbon sludge return, use the outlet water to flush the return pipeline to prevent carbon sludge from clogging the return pipeline. S82: Set up the second fault situation response measures: When the effluent COD is abnormal and the COD removal rate begins to rise, stop the return of powdered carbon sludge, increase the amount of new powdered carbon added, discharge saturated carbon sludge, monitor the removal rate in real time, and after the effluent meets the standards, gradually restore the return to a stable state and restart the wastewater treatment powdered carbon return and reuse work. S83: Set up a third type of fault response: If the sludge pump, submersible pump and other machinery and equipment malfunction, stop the backflow and backwashing work, switch to the backup equipment, and resume work after the main equipment has been inspected and maintained, and recalibrated and debugged. S84: Based on past operational failures, establish contingency plans for other failure scenarios to ensure the smooth operation of wastewater treatment.

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