Catalytic ozonation system and method capable of adaptively controlling ozone dosage

Abstract

The invention relates to a catalytic ozonation system and method capable of adaptively controlling ozone dosage, the system comprises a catalytic ozonation unit and an ozone dosage controller, the catalytic ozonation unit is provided with a water inlet pipe, a gas inlet pipe, a water outlet pipe and a gas outlet pipe, the gas inlet pipe is connected with an ozone generator, the ozone generator is provided with a variable-frequency power supply, and the variable-frequency power supply is connected with the ozone dosage controller. The water inlet pipe is provided with a flow meter and an inlet water quality detection device, the water outlet pipe is provided with an outlet water quality detection device, detection signal outputs of the flow meter and the water quality detection devices are connected to the ozone adding controller, and control signal outputs of the ozone adding controller are connected to the variable-frequency power supply and a control end of an oxygen inlet valve of the ozone generator. According to the method, the ozone adding amount of the catalytic ozonation unit is controlled by adopting the system according to a water quality detection data comparison result before and after wastewater treatment. The ozone adding amount of the system can be automatically adjusted according to the water quality characteristics of inlet and outlet water of the system, it is guaranteed that outlet water reaches the standard, the operation cost is saved, and the ozone utilization efficiency is improved.

Description

Technical Field

[0001] The invention relates to an ozone catalytic oxidation system for adaptively controlling ozone dosage and an ozone catalytic oxidation method for adaptively controlling ozone dosage using the system, belonging to the technical field of wastewater treatment. Background Art

[0002] Industrial production will generate a large amount of wastewater. With the continuous improvement of the national economy, the degree of refinement of various industries has gradually increased, and the composition of the wastewater generated has become more complex and diverse. Even though clean production has been vigorously promoted in industrial production in recent years, a large number of industrial chemical products are still transferred to the wastewater, making the wastewater have the significant characteristics of poor biodegradability, difficult degradation, and high biological toxicity, which brings increasing treatment pressure to sewage treatment plants. Traditional sewage treatment processes are no longer competent for the task of meeting the standards for treating this type of difficult-to-degrade wastewater. Based on this, advanced oxidation processes such as ozone, Fenton, and electrochemistry are increasingly being used in the treatment of industrial wastewater, which can effectively strongly oxidize and degrade organic matter in sewage to obtain a greater improvement in biodegradability, ensure the operability of the treatment process, and ensure that the drainage meets the standards.

[0003] As one of the most widely used technologies in advanced oxidation processes, ozone has been continuously promoted and used in China in the past decade or so, and there are also various wastewater treatment systems applying ozone. For example, the utility model patent with the publication number CN221235378U discloses an ozone multi-catalytic oxidation system, which includes a homogeneous catalytic oxidation unit, a heterogeneous catalytic oxidation unit and an effluent tank; the homogeneous catalytic oxidation unit includes a homogeneous treatment tank and a homogeneous electrolysis device arranged in the homogeneous treatment tank, and the homogeneous treatment tank is connected with a water inlet pipe; the heterogeneous catalytic oxidation unit includes an ozone dosing module and at least two groups of heterogeneous catalytic tank modules connected in sequence, and the output ends of the ozone dosing module respectively extend into the bottoms of each heterogeneous catalytic tank module; the input end of the heterogeneous catalytic tank module at the head end is connected with the output end of the homogeneous catalytic oxidation unit, and the output end of the heterogeneous catalytic tank module at the tail end is connected with the effluent tank; the effluent tank is connected with a water outlet pipe. This system adopts a treatment process combining homogeneous and heterogeneous methods, which can effectively improve the treatment effect on wastewater. Another example is that the utility model patent with the publication number CN220788240U discloses a treatment system for ozone catalytic oxidation of industrial wastewater, which includes a first ozone reaction unit, a second ozone reaction unit and an ozone generating device; the first ozone reaction unit includes a first ozone catalytic reactor; the second ozone reaction unit includes a second ozone catalytic reactor; the first ozone catalytic reactor is a fluidized bed catalytic reactor containing first catalyst particles, and the second ozone catalytic reactor is a fixed bed catalytic reactor containing second catalyst particles. This system is applied to the treatment of industrial wastewater, has a high organic matter removal efficiency and ozone utilization rate, improves the treatment efficiency of industrial wastewater, and also has the advantages of low investment and operation costs and convenient operation and management. The above ozone catalytic oxidation technologies have their own characteristics and are respectively suitable for their respective applicable application scenarios. However, in the above technologies, the ozone dosing amount of the system cannot be effectively controlled, which is extremely likely to cause the situation that due to insufficient ozone dosing amount, pollutants cannot be removed completely and the drainage does not meet the standards, or due to excessive ozone dosing amount, ozone is wasted and the burden of tail gas treatment is increased. Summary of the Invention

[0004] To overcome the above defects of the prior art, the present invention provides an ozone catalytic oxidation system and method for adaptively controlling the ozone dosing amount, which can automatically adjust the ozone dosing amount of the system according to the water quality characteristics of the inlet and outlet water of the system, ensure that the effluent meets the standards, and save the operation cost.

[0005] The technical solution of the present invention to achieve the above object is: an ozone catalytic oxidation system for adaptively controlling the ozone dosage, including an ozone catalytic oxidation unit and an ozone dosage controller. The ozone catalytic oxidation unit is provided with a water inlet pipe, an air inlet pipe, a water outlet pipe and an air outlet pipe. The air inlet pipe is connected to an ozone generator, and the ozone generator is provided with a variable frequency power supply. A flow meter and a water quality detection device for inlet water are provided on the water inlet pipe, and a water quality detection device for outlet water is provided on the water outlet pipe. The detection signal outputs of the flow meter and each water quality detection device are connected to the ozone dosage controller, and the control signal output of the ozone dosage controller is connected to the control end of the variable frequency power supply and the oxygen inlet valve of the ozone generator. The ozone dosage controller controls the ozone dosage of the ozone catalytic oxidation unit according to the comparison result of the water quality detection data before and after wastewater treatment.

[0006] Preferably, the adaptive control of the ozone dosage is implemented by combining feedforward control and feedback control.

[0007] Preferably, when the change of the inlet water parameters (the relevant parameters based on which the feedforward control is started) does not exceed the set threshold, the feedback control method is used to implement the adaptive control of the ozone dosage. When the change of the inlet water parameters exceeds the set threshold, the feedforward control method is used to implement the adaptive control of the ozone dosage, and the value of the relevant inlet water parameters when the feedforward control is started is used as the new standard value for subsequent judgment of the change of the inlet water parameters.

[0008] Preferably, the water quality detection device for inlet water and the water quality detection device for outlet water are the same water quality detection device, and the water quality detection device is at least one of a three-dimensional fluorescence spectrometer, an ultraviolet spectrophotometer, a pH meter, and an ORP meter, that is, the water quality detection device can be any one of a three-dimensional fluorescence spectrometer, an ultraviolet spectrophotometer, a pH meter, and an ORP meter, or can be a combination of any two or more.

[0009] Preferably, the flow meter adopts any one of an electromagnetic flow meter, a differential pressure flow meter, and a mass flow meter with the function of remotely transmitting detection signals.

[0010] Preferably, the ozone dosage controller adopts a PLC programmable controller or an industrial control computer.

[0011] Preferably, the ozone generator is a tubular ozone generator or a plate-type ozone generator. The variable frequency power supply is a variable frequency power supply that can realize voltage regulation, amplitude modulation, pulse, and variable frequency control, and the output power is preferably 20Hz - 100Hz.

[0012] Preferably, the ozone catalytic oxidation unit is provided with an ozone catalytic oxidation chamber, which is provided with a water inlet, an air inlet, a water outlet and an air outlet. The water inlet and the air outlet are arranged at the top of the ozone catalytic oxidation chamber, and the air inlet and the water outlet are arranged at the lower part of the ozone catalytic oxidation chamber. Inside the ozone catalytic oxidation chamber, there are a water distribution device communicated with the water inlet, an air distribution device communicated with the air inlet, a water collection device communicated with the water outlet and a catalyst layer. The water distribution device is located in the upper part of the ozone catalytic oxidation chamber, the air distribution device and the water collection device are located in the lower part of the ozone catalytic oxidation chamber, and the water collection device is located below the air distribution device. The catalyst layer is located between the water distribution device and the air distribution device.

[0013] Preferably, the number of the ozone catalytic oxidation chambers is several, and several ozone catalytic oxidation chambers are connected in sequence. The water outlet and the air outlet of the previous-stage ozone catalytic oxidation chamber are respectively connected to the water inlet and the air inlet of the next-stage ozone catalytic oxidation chamber. The water inlet and the air inlet of the first-stage ozone catalytic oxidation chamber are respectively connected to the water inlet pipe and the air inlet pipe.

[0014] Furthermore, the number of the ozone catalytic oxidation chambers is two, namely a first-stage ozone catalytic oxidation chamber and a second-stage ozone catalytic oxidation chamber. Both the first-stage ozone catalytic oxidation chamber and the second-stage ozone catalytic oxidation chamber are provided with liquid level gauges.

[0015] The main structure of the ozone catalytic oxidation chamber can be a concrete pool or a steel device. When a steel device is adopted, the structural material is preferably S316L or carbon steel lined with rubber or PO.

[0016] Preferably, the air distribution device includes an air distribution main pipe and a plurality of air distribution branch pipes cross-connected with the air distribution main pipe. The air distribution main pipe is connected to the air inlet of the ozone catalytic oxidation chamber, and microporous aerators are densely arranged on the air distribution main pipe and each air distribution branch pipe.

[0017] The air distribution branch pipes can be straight pipes. Each air distribution branch pipe is vertically cross-connected with the air distribution main pipe. There is a space between adjacent air distribution branch pipes and the spaces between any adjacent air distribution branch pipes are the same. The air distribution branch pipes can also be annular pipes. A plurality of air distribution branch pipes are concentrically arranged on the same plane. There is a space (a radial space) between adjacent air distribution branch pipes and the spaces between any adjacent air distribution branch pipes are the same.

[0018] Preferably, the microporous aerators are uniformly distributed on the air distribution main pipe and the air distribution branch pipes.

[0019] Preferably, the water distribution device includes a main water distribution pipe and a plurality of water distribution branch pipes that intersect and communicate with the main water distribution pipe. The main water distribution pipe is connected to the water inlet of the ozone catalytic oxidation chamber, and downwardly inclined water outlet holes are densely arranged on the main water distribution pipe and each of the water distribution branch pipes.

[0020] The water distribution branch pipes can be straight pipes. Each of the water distribution branch pipes intersects and communicates with the main water distribution pipe perpendicularly. There is a spacing between adjacent water distribution branch pipes and the spacing between any adjacent water distribution branch pipes is the same. The water distribution branch pipes can also be annular pipes. A plurality of water distribution branch pipes are concentrically arranged on the same plane. There is a spacing between adjacent water distribution branch pipes (a spacing in the radial direction) and the spacing between any adjacent water distribution branch pipes is the same.

[0021] Preferably, the angle between the axis of the water outlet hole and the vertical line perpendicular to the corresponding pipe is 45°.

[0022] Preferably, two water outlet holes are provided on the same cross-section of the pipe, and the inclination directions of the two water outlet holes with respect to the vertical line perpendicular to the pipe are opposite. Or one water outlet hole is provided on the same cross-section of the pipe, and the inclination directions of any two adjacent water outlet holes on the pipe with respect to the vertical line perpendicular to the pipe are opposite.

[0023] Preferably, the water outlet holes are evenly distributed on the main water distribution pipe and the water distribution branch pipes.

[0024] Preferably, the installation position of the water distribution device is higher than the water surface during the normal operation of the ozone catalytic oxidation chamber.

[0025] Preferably, the water outlet collection device includes a main water outlet pipe and a plurality of water outlet branch pipes that intersect and communicate with the main water outlet pipe. The main water outlet pipe is connected to the water outlet of the ozone catalytic oxidation chamber or communicates with the water outlet of the ozone catalytic oxidation chamber and extends out of the water outlet of the ozone catalytic oxidation chamber (sealed connection is provided between the main water outlet pipe and the wall of the water outlet of the ozone catalytic oxidation chamber), and downwardly inclined water inlet holes are densely arranged on the main water outlet pipe and each of the water outlet branch pipes.

[0026] The water outlet branch pipes can be straight pipes. Each of the water outlet branch pipes intersects and communicates with the main water outlet pipe perpendicularly. There is a spacing between adjacent water outlet branch pipes and the spacing between any adjacent water outlet branch pipes is the same. The water outlet branch pipes can also be annular pipes. A plurality of water outlet branch pipes are concentrically arranged on the same plane. There is a spacing between adjacent water outlet branch pipes (a spacing in the radial direction) and the spacing between any adjacent water outlet branch pipes is the same.

[0027] Preferably, the angle between the axis of the water inlet hole and the vertical line perpendicular to the corresponding pipe is 45°.

[0028] Preferably, two of the water inlet holes are provided on the same cross-section of the pipeline, and the inclination directions of the two water inlet holes with respect to the vertical line perpendicular to the pipeline are opposite, or one of the water inlet holes is provided on the same cross-section of the pipeline, and the inclination directions of any two adjacent water inlet holes on the pipeline with respect to the vertical line perpendicular to the pipeline are opposite.

[0029] Preferably, the water inlet holes are evenly distributed on the main water outlet pipe and the branch water outlet pipes.

[0030] The water outlet collection device also serves as the backwashing water device of the ozone catalytic oxidation chamber.

[0031] Preferably, a supporting layer is provided at the bottom of the catalyst layer. The supporting layer (which may be provided with a suitable supporting bracket) can be a cobblestone layer or an inert porcelain ball layer. The particle size of the cobblestones or inert porcelain balls is not less than 7 mm, and the height (or thickness) of the supporting layer is not less than 200 mm. The catalyst of the catalyst layer can be any spherical solid catalyst of a multi-metal oxide type suitable for wastewater catalytic oxidation under the existing technology.

[0032] Preferably, the air distribution device is arranged in the supporting layer.

[0033] Preferably, a filter plate is provided between the catalyst layer (including the supporting layer) and the water outlet collection device. The filter plate is a perforated plate, and filter heads (or filter caps) are installed on the plate holes.

[0034] Preferably, the inlet air pipe is provided with inlet air branch pipes. The inlet air pipe and the inlet air branch pipes can be connected through a tee. An air compressor is provided on the inlet air branch pipes, and corresponding inlet air regulating valves are provided on the inlet air pipe and the inlet air branch pipes at the front end of the tee.

[0035] Preferably, the ozone catalytic oxidation system for adaptively controlling the ozone dosage further includes a tail gas circulation chamber and a tail gas destroyer. The tail gas circulation chamber is provided with a water inlet, an air inlet, a water outlet and an air outlet. The water inlet, the air inlet and the air outlet of the tail gas circulation chamber are arranged at its upper part. The water outlet of the tail gas circulation chamber is arranged at its lower part and is connected with a drain pipe. The water quality detection device is arranged on the drain pipe. The water inlet and the air inlet of the tail gas circulation chamber are respectively connected with the water outlet pipe and the air outlet pipe of the ozone catalytic oxidation unit. The air outlet of the tail gas circulation chamber is connected with the air inlet of the tail gas destroyer through an exhaust pipe. A fan is provided on the exhaust pipe. A gas distribution device is arranged at the lower part inside the tail gas circulation chamber. A tail gas circulation pipe is connected to the exhaust pipe between the fan and the tail gas destruction chamber, and the outlet of the tail gas circulation pipe is connected with the gas distribution device of the tail gas circulation chamber.

[0036] Preferably, the drain pipe is provided with a drain branch pipe, and the two can be connected through a tee. A water pump (or a drainage circulation pump) is provided on the drain branch pipe, and the drain branch pipe is connected to the water inlet pipe.

[0037] Preferably, the air distribution device in the tail gas circulation chamber includes a main air distribution pipe and a plurality of air distribution branch pipes that cross-connect with the main air distribution pipe. The main air distribution pipe is connected to the tail gas circulation pipe, and downwardly inclined air outlet holes are densely arranged on the main air distribution pipe and each air distribution branch pipe.

[0038] The air distribution branch pipes can be straight pipes. Each air distribution branch pipe vertically crosses and connects with the main air distribution pipe. There is a distance between adjacent air distribution branch pipes and the distances between any adjacent air distribution branch pipes are the same. The air distribution branch pipes can also be annular pipes. A plurality of air distribution branch pipes are concentrically arranged on the same plane. There is a distance (a radial distance) between adjacent air distribution branch pipes and the distances between any adjacent air distribution branch pipes are the same.

[0039] Preferably, the angle between the axis of the air outlet hole and the vertical straight line perpendicular to the corresponding pipe is 45°.

[0040] Preferably, two air outlet holes are provided on the same cross-section of the pipe, and the inclination directions of the two air outlet holes with respect to the vertical straight line perpendicular to the pipe are opposite. Or one air outlet hole is provided on the same cross-section of the pipe, and the inclination directions of any two adjacent air outlet holes on the pipe with respect to the vertical straight line perpendicular to the pipe are opposite.

[0041] Preferably, the air outlet holes are evenly distributed on the main air distribution pipe and the air distribution branch pipes.

[0042] Preferably, the tail gas circulation chamber is provided with a circulating water pipe. The inlet of the circulating water pipe is connected to the upper part of the tail gas circulation chamber, and the connection position is not higher than the water surface in the normal working state of the tail gas circulation chamber. The outlet of the circulating water pipe is connected to the water inlet of the tail gas circulation chamber or the water outlet pipe of the ozone catalytic oxidation unit. A micro-nano bubble generator in the form of a Venturi tube is provided on the circulating water pipe. The suction port (or air inlet) of the micro-nano bubble generator is connected to the upper part of the tail gas circulation chamber (the connection position is higher than the water surface in the normal working state of the tail gas circulation chamber), the air outlet of the tail gas circulation chamber or the exhaust pipe. A water pump is provided on the circulating water pipe in front of the micro-nano bubble generator.

[0043] Preferably, the ozone catalytic oxidation system for adaptively controlling the ozone dosage further includes a wastewater pretreatment device, and the water outlet of the wastewater pretreatment device is connected to the water inlet pipe of the ozone catalytic oxidation unit.

[0044] The wastewater pretreatment device is any one of a flocculation sedimentation tank, an inclined plate clarifier, a high-efficiency sedimentation tank, a dissolved air flotation unit, a sand filter, and a multi-media filter, or a series combination of any two or more of them.

[0045] Preferably, appropriate on-off control valves are provided on each pipeline of the ozone catalytic oxidation system for adaptively controlling the ozone dosage.

[0046] An ozone catalytic oxidation method for adaptively controlling the ozone dosage adopts any one of the ozone catalytic oxidation systems for adaptively controlling the ozone dosage disclosed in the present invention. The ozone dosage controller determines whether the ozone catalytic oxidation degree matches the removal amount of characteristic pollutants based on the real-time detection data of the flowmeter and each water quality detection device. When they do not match, a compensation value for the ozone dosage is calculated based on the real-time detection data according to the pre-obtained correlation between the ozone dosage and the detection data. Then, based on the compensation value of the ozone dosage, the frequency conversion power supply and the oxygen inlet valve are controlled to perform corresponding operations in a way of feedback control and / or feedforward control according to the pre-obtained correlation between the ozone dosage and the frequency conversion range of the frequency conversion power supply and the adjustment degree of the oxygen inlet valve, so as to realize the adaptive control of the ozone dosage.

[0047] When the influent water quality of the ozone catalytic oxidation system for adaptively controlling the ozone dosage is relatively constant (the influent water quality is within a certain threshold range), the frequency conversion power supply and the oxygen inlet valve are controlled to perform corresponding control operations in a way of feedback control; when the influent water quality of the ozone catalytic oxidation system for adaptively controlling the ozone dosage often fluctuates greatly (the influent water quality often exceeds a certain threshold range), the corresponding control operations (feedback control) performed on the frequency conversion power supply and the oxygen inlet valve are estimated and compensated in a way of feedforward control, and the feedback control signal is used as a correction. For example, when the influent water flow of the ozone catalytic oxidation system for adaptively controlling the ozone dosage exceeds the preset influent water flow threshold, the corresponding control operations (feedback control) performed on the frequency conversion power supply and the oxygen inlet valve are directly compensated in a way of feedforward control according to the ratio between the real-time influent water flow and the preset influent water flow threshold.

[0048] The beneficial effects of the present invention are as follows: The ozone catalytic oxidation system of the present invention enhances the effective contact efficiency, contact time between ozone and wastewater, and the solubility of ozone in wastewater through the reverse convection mode of ozone and wastewater, thereby realizing the high utilization rate of ozone. Moreover, it can quickly adjust the system operation control parameters according to the changes in the water quality characteristic parameters of the influent and effluent, realizing the real-time self-regulation of the ozone dosage. That is, under the condition of the removal rate of the characteristic pollutants designed by the predetermined ozone process, the ozone dosage is automatically increased or decreased to make the ozone catalytic oxidation degree of the wastewater match the removal amount of the characteristic pollutants, ensuring that the quality of the final effluent meets the standards, saving the system operation cost, and realizing the automatic control of the system operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 FIG. is a schematic structural diagram of an embodiment of the ozone catalytic oxidation system for adaptively controlling the ozone dosage of the present invention; Figure 2 FIG. is a schematic structural diagram of an embodiment of the ozone catalytic oxidation chamber of the present invention; Figure 3 FIG. is a schematic structural diagram of an embodiment of the water distribution device of the present invention; Figure 4 FIG. is a schematic cross-sectional structural diagram of an embodiment of the water distribution branch pipe of the present invention; Figure 5 FIG. is a flow chart of the ozone catalytic oxidation method for adaptively controlling the ozone dosage of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0050] See Figure 1, the present invention discloses an ozone catalytic oxidation system for adaptively controlling the ozone dosage, which includes an ozone catalytic oxidation unit and an ozone dosage controller 1. The ozone catalytic oxidation unit is used for ozone catalytic oxidation treatment of wastewater to remove characteristic pollutants in the wastewater, such as COD, TOC, etc. The ozone dosage controller is used to control the ozone dosage of the ozone catalytic oxidation unit so that the ozone catalytic oxidation degree of the wastewater in the ozone catalytic oxidation unit matches the removal amount of the characteristic pollutants. The ozone catalytic oxidation unit is provided with a water inlet pipe, an air inlet pipe, a water outlet pipe and an air outlet pipe. The water inlet pipe is used for wastewater to enter the ozone catalytic oxidation unit, the air inlet pipe is used for ozone to enter the ozone catalytic oxidation unit, the water outlet pipe is used for the catalytically oxidized wastewater to discharge from the ozone catalytic oxidation unit, and the air outlet pipe is used for the catalytically oxidized waste gas to discharge from the ozone catalytic oxidation unit. The air inlet pipe is connected to an ozone generator 2 to provide ozone required for wastewater catalytic oxidation for the ozone catalytic oxidation unit. The ozone generator is provided with a variable frequency power supply. A flowmeter 3 and an influent water quality detection device 4 are arranged on the water inlet pipe, which are respectively used to detect the influent water flow and influent water quality of the ozone catalytic oxidation unit. An effluent water quality detection device 5 is arranged on the water outlet pipe, which is used to detect the effluent water quality of the ozone catalytic oxidation unit. The detection signal outputs of the flowmeter and each water quality detection device are connected to the ozone dosage controller. The control signal output of the ozone dosage controller is connected to the control end of the variable frequency power supply and the oxygen inlet valve of the ozone generator. The ozone dosage controller controls the ozone dosage of the ozone catalytic oxidation unit according to the comparison result of the water quality detection data before and after wastewater treatment, realizes the real-time self-adjustment of the ozone dosage, that is, under the condition of the characteristic pollutant removal rate designed by the predetermined ozone process, automatically increases or decreases the ozone dosage to make the ozone catalytic oxidation degree of the wastewater match the removal amount of the characteristic pollutants, ensures the compliance of the final effluent water quality and the economic effectiveness of the ozone dosage, saves the system operation cost, realizes the automatic control of the system operation, and can better connect with the subsequent biochemical process and provide ozone surplus for the operation of the subsequent process.

[0051] The influent water quality detection device and the effluent water quality detection device adopt the same water quality detection device. The water quality detection device is preferably at least one of a three-dimensional fluorescence spectrometer, an ultraviolet spectrophotometer, a pH meter, and an ORP meter, that is, the water quality detection device can be any one of a three-dimensional fluorescence spectrometer, an ultraviolet spectrophotometer, a pH meter, and an ORP meter, or any combination of two or more. The water quality detection device can also adopt other suitable water quality detection devices under the existing technology, such as a laser spectrometer or a fluorescence spectrophotometer, etc. The real-time reaction period of the water quality detection device for water quality is preferably 1 s - 5 min, or even less.

[0052] Preferably, any one of an electromagnetic flowmeter, a differential pressure flowmeter, and a mass flowmeter with a function of remotely transmitting detection signals is adopted as the flowmeter.

[0053] Preferably, a PLC programmable controller or an industrial control computer is adopted as the ozone dosing controller.

[0054] The ozone generator may adopt a tubular ozone generator or a plate-type ozone generator. The variable-frequency power supply is a variable-frequency power supply that can realize voltage regulation, amplitude modulation, pulse, and variable-frequency control, and the output power is preferably 20 Hz - 100 Hz.

[0055] See Figure 2 , an ozone catalytic oxidation unit is provided with an ozone catalytic oxidation chamber 6. The ozone catalytic oxidation chamber is provided with a water inlet, an air inlet, a water outlet, and an air outlet. The water inlet is used to introduce the wastewater to be treated into the ozone catalytic oxidation chamber. The air inlet is used to input ozone into the ozone catalytic oxidation chamber. The water outlet is used to discharge the wastewater treated in the ozone catalytic oxidation chamber. The air outlet is used to discharge the waste gas after the catalytic oxidation reaction in the ozone catalytic oxidation chamber. The water inlet and the air outlet are arranged at the top of the ozone catalytic oxidation chamber. The air inlet and the water outlet are arranged at the lower part of the ozone catalytic oxidation chamber. A water distribution device 7 communicated with the water inlet, an air distribution device 8 communicated with the air inlet, a water collection device 9 communicated with the water outlet, and a catalyst layer 10 are arranged in the ozone catalytic oxidation chamber. The water distribution device is located in the upper part of the ozone catalytic oxidation chamber and above the water surface during the normal operation of the ozone catalytic oxidation chamber. The air distribution device and the water collection device are located in the lower part of the ozone catalytic oxidation chamber, and the water collection device is located below the air distribution device. The catalyst layer is located between the water distribution device and the air distribution device. With such an arrangement, ozone enters the ozone catalytic oxidation reaction chamber from bottom to top, and wastewater enters the ozone catalytic oxidation reaction chamber from top to bottom. In the ozone catalytic oxidation reaction chamber, the effective contact efficiency, contact time between ozone and wastewater, and the solubility of ozone in wastewater are enhanced by the countercurrent convection mode of ozone and wastewater, thereby realizing the high utilization rate of ozone.

[0056] Preferably, the number of the ozone catalytic oxidation chambers is several. The several ozone catalytic oxidation chambers are connected in sequence. The water outlet and the air outlet of the previous-stage ozone catalytic oxidation chamber are respectively connected to the water inlet and the air inlet of the next-stage ozone catalytic oxidation chamber to realize multi-stage ozone catalytic oxidation treatment of wastewater, so as to improve the treatment effect of wastewater. The water inlet and the air inlet of the first-stage ozone catalytic oxidation chamber are respectively connected to the water inlet pipe and the air inlet pipe.

[0057] A preferred embodiment is that the number of the ozone catalytic oxidation chambers is two, namely a primary ozone catalytic oxidation chamber and a secondary ozone catalytic oxidation chamber. The primary ozone catalytic oxidation chamber and the secondary ozone catalytic oxidation chamber are both provided with liquid level gauges for respectively monitoring the water levels in the primary ozone catalytic oxidation chamber and the secondary ozone catalytic oxidation chamber.

[0058] The ozone catalytic oxidation chamber is a closed container, and its main structure can adopt a concrete pool or a steel device. When a steel device is adopted, the structural material is preferably S316L or carbon steel lined with rubber or PO.

[0059] The air distribution device is preferably horizontally arranged and includes an air distribution main pipe and a plurality of air distribution branch pipes cross-connected with the air distribution main pipe. The air distribution main pipe is connected to the air inlet of the ozone catalytic oxidation chamber, and microporous aerators are densely arranged on the air distribution main pipe and each air distribution branch pipe. The air distribution main pipe and the air distribution branch pipes can adopt an ozone-resistant material not lower than 2205 duplex steel, and the microporous aerators can adopt microporous aerators made of pure titanium or titanium alloy to avoid damage caused by oxidation and reduce the service life.

[0060] The air distribution branch pipes can be straight pipes. Each air distribution branch pipe is vertically cross-connected with the air distribution main pipe, and there is a spacing between adjacent air distribution branch pipes and the spacing between any adjacent air distribution branch pipes is the same. The air distribution branch pipes can also be annular pipes. A plurality of air distribution branch pipes are concentrically arranged on the same plane, and there is a spacing between adjacent air distribution branch pipes (a spacing in the radial direction) and the spacing between any adjacent air distribution branch pipes is the same. The microporous aerators are preferably evenly distributed on the air distribution main pipe and the air distribution branch pipes to make the air distribution uniform. The microporous aerators can also be only arranged on the air distribution branch pipes and not on the air distribution main pipe.

[0061] See Figure 3 and Figure 4 As shown in and, the water distribution device is preferably horizontally arranged and includes a water distribution main pipe 11 and a plurality of water distribution branch pipes 12 cross-connected with the water distribution main pipe. The water distribution main pipe is connected to the water inlet of the ozone catalytic oxidation chamber, and downwardly inclined water outlet holes 13 are densely arranged on the water distribution main pipe and each water distribution branch pipe.

[0062] The water distribution branch pipes can be straight pipes. Each water distribution branch pipe is vertically cross-connected with the water distribution main pipe, and there is a spacing between adjacent water distribution branch pipes and the spacing between any adjacent water distribution branch pipes is the same. The water distribution branch pipes can also be annular pipes. A plurality of water distribution branch pipes are concentrically arranged on the same plane, and there is a spacing between adjacent water distribution branch pipes (a spacing in the radial direction) and the spacing between any adjacent water distribution branch pipes is the same.

[0063] The included angle between the axis of the water outlet hole and the vertical line perpendicular to the corresponding pipe is preferably 45°. Two water outlet holes are provided on the same cross-section of the pipe, and the inclination directions of the two water outlet holes with respect to the vertical line perpendicular to the pipe are opposite, or one water outlet hole is provided on the same cross-section of the pipe, and the inclination directions of any two adjacent water outlet holes on the pipe with respect to the vertical line perpendicular to the pipe are opposite. With such a setting, it can not only ensure uniform water distribution but also play a role in defoaming (no additional wire mesh foam remover or spraying device needs to be installed in the ozone catalytic oxidation chamber for defoaming). The water outlet holes are preferably evenly distributed on the water distribution main pipe and the water distribution branch pipes to achieve uniform water distribution. The water outlet holes can also be provided only on the water distribution branch pipes and not on the water distribution main pipe. The installation position of the water distribution device is higher than the water surface during the normal operation of the ozone catalytic oxidation chamber.

[0064] The water outlet collection device is preferably horizontally arranged and includes a water outlet main pipe and a plurality of water outlet branch pipes cross-connecting with the water outlet main pipe. The water outlet main pipe is connected to the water outlet of the ozone catalytic oxidation chamber or communicates with the water outlet of the ozone catalytic oxidation chamber and extends out of the water outlet of the ozone catalytic oxidation chamber (sealed connection is provided between the water outlet main pipe and the wall of the water outlet of the ozone catalytic oxidation chamber), and inclined downward water inlet holes are densely arranged on the water outlet main pipe and each water outlet branch pipe.

[0065] The water outlet branch pipes can be straight pipes, and each water outlet branch pipe is vertically cross-connected with the water outlet main pipe. There is a gap between adjacent water outlet branch pipes and the gaps between any two adjacent water outlet branch pipes are the same. The water outlet branch pipes can also be annular pipes, and a plurality of water outlet branch pipes are concentrically arranged on the same plane. There is a gap between adjacent water outlet branch pipes (a gap is left in the radial direction) and the gaps between any two adjacent water outlet branch pipes are the same.

[0066] The included angle between the axis of the water inlet hole and the vertical line perpendicular to the corresponding pipe is preferably 45°. Two water inlet holes are provided on the same cross-section of the pipe, and the inclination directions of the two water inlet holes with respect to the vertical line perpendicular to the pipe are opposite, or one water inlet hole is provided on the same cross-section of the pipe, and the inclination directions of any two adjacent water inlet holes on the pipe with respect to the vertical line perpendicular to the pipe are opposite. The water inlet holes are preferably evenly distributed on the water outlet main pipe and the water outlet branch pipes to achieve uniform water outlet. The water outlet holes can also be provided only on the water outlet branch pipes and not on the water outlet main pipe. The water outlet collection device can also serve as the backwashing water device of the ozone catalytic oxidation chamber.

[0067] A supporting layer is usually provided at the bottom of the catalyst layer. The supporting layer (equipped with a suitable support bracket) can be a cobblestone layer or an inert porcelain ball layer. The particle size of the cobblestones or inert porcelain balls is not less than 7 mm, and the height (or thickness) of the supporting layer is not less than 200 mm. The catalyst in the catalyst layer can be a spherical solid catalyst of any multi-metal oxide type suitable for catalytic oxidation of wastewater under the existing technology. The air distribution device is preferably arranged in the supporting layer to ensure that the ozone gas introduced into the ozone catalytic oxidation chamber is in a dispersed state after dilution and contacts and reacts with the catalyst in the catalyst layer to the maximum extent.

[0068] A filter plate 14 is preferably provided between the catalyst layer (including the supporting layer) and the effluent collection device (the catalyst layer can be arranged on the filter plate) for filtering and backwashing water distribution. The filter plate is a horizontal perforated plate, and filter heads (or filter caps) are installed on the plate holes.

[0069] The catalyst layer can be provided with an air washing device to add an air washing function on the basis of water washing to improve the backwashing ability.

[0070] The inlet pipe is preferably provided with inlet branch pipes. The inlet pipe and the inlet branch pipes can be connected through a tee. An air compressor is provided on the inlet branch pipe, and corresponding inlet regulating valves are provided on the inlet pipe and the inlet branch pipe at the front end of the tee. The arrangement of the inlet branch pipe and the air compressor can, on the one hand, increase the air supply volume, thereby increasing the mass transfer and exchange effect between the gas and the sewage, and on the other hand, supplement the pressure of the gas entering the ozone catalytic oxidation unit to make up for the pressure loss of the gas during the operation of the system and ensure that the gas can be normally distributed in a dispersed manner by the air distribution devices in the ozone catalytic oxidation chambers at all levels.

[0071] The ozone catalytic oxidation system for adaptively controlling the ozone dosage further includes an off-gas circulation chamber 15 and an off-gas destructor 16. The off-gas circulation chamber is used for recycling the off-gas of the ozone catalytic oxidation unit, and the off-gas destructor is used to decompose the final off-gas into harmless substances for evacuation. The off-gas circulation chamber is provided with a water inlet, an air inlet, a water outlet and an air outlet. The water inlet, air inlet and air outlet of the off-gas circulation chamber are arranged at its upper part, and the water outlet of the off-gas circulation chamber is arranged at its lower part and is connected with a drain pipe. The effluent water quality detection device is arranged on the drain pipe and is used to detect the water quality of the final effluent. The water inlet and air inlet of the off-gas circulation chamber are respectively connected with the water outlet pipe and the air outlet pipe of the ozone catalytic oxidation unit. The air outlet of the off-gas circulation chamber is connected with the air inlet of the off-gas destructor through an exhaust pipe. A blower (such as a high-pressure centrifugal blower, a rotary blower, a side-flow blower, a Roots blower, etc.) is arranged on the exhaust pipe. A gas distribution device is arranged at the lower part inside the off-gas circulation chamber, and the gas distribution device is arranged below the water surface in the normal working state of the off-gas circulation chamber. A tail gas circulation pipe is connected to the exhaust pipe between the blower and the off-gas destruction chamber, and the outlet of the tail gas circulation pipe is connected to the gas distribution device of the off-gas circulation chamber, which is used to circulate the discharged off-gas into the off-gas circulation chamber to perform surface aeration on the wastewater in the off-gas circulation chamber, so as to realize the recycling of the off-gas.

[0072] Preferably, the drain pipe is provided with a drain branch pipe, and the two can be connected through a tee. A water pump (or called a drainage circulation pump) is arranged on the drain branch pipe, and the drain branch pipe is connected to the water inlet pipe to achieve the gas-liquid balance of the ozone catalytic oxidation system and prevent the local liquid level imbalance caused by the gas-liquid connection of multiple ozone catalytic oxidation chambers or the full liquid situation in the first-stage ozone catalytic oxidation chamber.

[0073] Preferably, the gas distribution device in the off-gas circulation chamber is horizontally arranged and includes a gas distribution main pipe and a plurality of gas distribution branch pipes that are cross-connected with the gas distribution main pipe. The gas distribution main pipe is connected to the tail gas circulation pipe, and inclined downward air outlet holes are densely arranged on the gas distribution main pipe and each gas distribution branch pipe.

[0074] The gas distribution branch pipes can be straight pipes, and each gas distribution branch pipe is vertically cross-connected with the gas distribution main pipe. There is a distance between adjacent gas distribution branch pipes and the distance between any adjacent gas distribution branch pipes is the same. The gas distribution branch pipes can also be annular pipes, and a plurality of gas distribution branch pipes are concentrically arranged on the same plane. There is a distance (a radial distance) between adjacent gas distribution branch pipes and the distance between any adjacent gas distribution branch pipes is the same.

[0075] The included angle between the axis of the air outlet and the vertical line perpendicular to the corresponding pipeline is preferably 45°. Two air outlets are provided on the same cross-section of the pipeline, and the inclination directions of the two air outlets with respect to the vertical line perpendicular to the pipeline are opposite, or one air outlet is provided on the same cross-section of the pipeline, and the inclination directions of any two adjacent air outlets on the pipeline with respect to the vertical line perpendicular to the pipeline are opposite. The air outlets are preferably evenly distributed on the main air distribution pipe and the branch air distribution pipes to achieve uniform air distribution. The air outlets can be provided only on the branch air distribution pipes and not on the main air distribution pipe.

[0076] The tail gas circulation chamber may also be provided with a circulating water pipe. The inlet of the circulating water pipe is connected to the upper part of the tail gas circulation chamber, and the connection position is not higher than the water surface in the normal working state of the tail gas circulation chamber. The outlet of the circulating water pipe is connected to the water inlet of the tail gas circulation chamber or the water outlet pipe of the ozone catalytic oxidation unit. A micro-nano bubble generator (or dissolved air diffuser) in the form of a Venturi tube is provided on the circulating water pipe. The suction port (or air inlet) of the micro-nano bubble generator is connected to the upper part of the tail gas circulation chamber (the connection position is higher than the water surface in the normal working state of the tail gas circulation chamber), the air outlet of the tail gas circulation chamber or the exhaust pipe. A water pump is provided on the circulating water pipe in front of the micro-nano bubble generator. With such a setting, the wastewater circulation in the tail gas circulation chamber can be realized, and during the circulation process, the tail gas (residual ozone gas) in the tail gas circulation chamber is sucked into the micro-nano bubble generator by the negative pressure suction generated by the micro-nano bubble generator, and a mixed liquid with a large number of uniform micro-nano bubbles is sent into the tail gas circulation chamber to enable the reuse of ozone and complete the final treatment.

[0077] The ozone catalytic oxidation system for adaptively controlling the ozone dosage also includes a wastewater pretreatment device 17. The water outlet of the wastewater pretreatment device is connected to the water inlet pipe of the ozone catalytic oxidation unit, and is used for pre-treating the wastewater sent into the ozone catalytic oxidation unit, such as flocculation, sedimentation, air flotation and / or filtration, to reduce the suspended solids in the wastewater and reduce the additional consumption of ozone by the suspended solids. The wastewater pretreatment device can adopt any one of a flocculation sedimentation tank, an inclined plate clarifier, a high-efficiency sedimentation tank, a dissolved air flotation device, a sand filter, a multi-media filter, or a series combination of any two or more of them.

[0078] Appropriate on-off control valves are provided on each pipeline of the ozone catalytic oxidation system for adaptively controlling the ozone dosage, so as to control the on-off of the corresponding pipeline according to the actual working conditions.

[0079] Taking the ozone catalytic oxidation system with two - stage ozone catalytic oxidation chambers as an example, its main operation process is as follows: After the wastewater is treated by the wastewater pretreatment device and the effluent is discharged, the SS (suspended solids) of the wastewater is less than 20, and the pH is maintained at 8.5 - 10. The wastewater enters from the top of the first - stage ozone catalytic oxidation chamber, and ozone gas is distributed from the bottom of the first - stage ozone catalytic oxidation chamber. The interior of the first - stage ozone catalytic oxidation chamber is in a state of counter - current flow of gas and water. The first - stage ozone catalytic oxidation chamber is a closed pressure - bearing container. After the wastewater is catalytically oxidized in the first - stage ozone catalytic oxidation chamber, it is discharged from the effluent collection device at the bottom and then sent to the second - stage ozone catalytic oxidation chamber through a pipeline. After the ozone gas enters through the gas distribution device at the bottom of the first - stage ozone catalytic oxidation chamber, it is sent to the gas distribution device at the bottom of the second - stage ozone catalytic oxidation chamber through the pipeline at the top of the first - stage ozone catalytic oxidation chamber by using the residual pressure of ozone for secondary gas distribution in the second - stage ozone catalytic oxidation chamber to treat the wastewater in the second - stage ozone catalytic oxidation chamber. The effluent at the bottom of the second - stage ozone catalytic oxidation chamber is sent to the tail gas circulation chamber, and the residual gas at the top of the second - stage ozone catalytic oxidation chamber is sent to the tail gas circulation chamber through a pipeline. The tail gas in the tail gas circulation chamber is circulated to the gas distribution device installed within 0.5 m below the water surface in the tail gas circulation chamber for surface aeration to treat the wastewater again. The wastewater after being treated again in the tail gas circulation chamber is discharged from the drain pipe. The tail gas in the tail gas circulation chamber is sent to the tail gas destroyer to be decomposed into harmless substances and discharged. According to actual needs, the wastewater in the tail gas circulation chamber can be circulated by a water pump, and the tail gas in the tail gas circulation chamber can be sucked by the micro - nano bubble generator to form a mixed liquid with a large number of uniform micro - nano bubbles and sent into the tail gas circulation chamber to make ozone reused again.

[0080] In practical applications, if the requirement for the ozone catalytic oxidation removal rate is not high, a simple system composed of one ozone catalytic oxidation chamber and the tail gas circulation chamber, or only two ozone catalytic oxidation chambers (without using the tail gas circulation chamber) can be used to treat the wastewater.

[0081] See Figure 5, the present invention also discloses an ozone catalytic oxidation method for adaptively controlling the ozone dosage. Using any one of the ozone catalytic oxidation systems for adaptively controlling the ozone dosage disclosed in the present invention, the ozone dosage controller determines whether the degree of ozone catalytic oxidation matches the removal amount of characteristic pollutants based on the real-time detection data of the flow meter and each water quality detection device. When they do not match, based on the real-time detection data, a compensation value for the ozone dosage is calculated according to the pre-obtained correlation relationship between the ozone dosage and the detection data, and then based on the compensation value of the ozone dosage, according to the pre-obtained correlation relationship between the ozone dosage and the frequency conversion amplitude of the variable frequency power supply and the adjustment degree of the oxygen intake valve, the variable frequency power supply and the oxygen intake valve are controlled to perform corresponding operations in a way of feedback control and / or feedforward control, so as to realize the adaptive control of the ozone dosage.

[0082] The effluent water quality data compared with the influent water quality data is obtained according to the actual residence time at intervals.

[0083] For the data fed back by the water quality detection device, the correlation relationship between the two is obtained through preliminary experiments. For example, for the characteristic peak intensity corresponding to the three-dimensional fluorescence spectrum matrix data obtained and the characteristic intensity corresponding to the UV data, a functional relationship with the COD and TOC (characteristic pollutants) of the specific wastewater to be treated can be obtained by linear or nonlinear fitting.

[0084] When the water quality detection device uses a three-dimensional fluorescence spectrometer, according to the properties of the raw water, the data results shown by the three-dimensional fluorescence spectrum data can achieve at least three-dimensional correlation methods. For example, the migration and disappearance of the fluorescence response characteristic peaks or the characteristic fluorescence index can be used as the reaction end point for the design of the ozone reaction system. Among them, the migration situation is to monitor the movement trajectory of the Ex / Em coordinates of the characteristic peak point. When the Ex / Em coordinates of the fluorescence response characteristic peak of a main characteristic pollutant in the raw water move from point A (starting point) to point B (ending point), it means that a certain characteristic pollutant in the raw water has undergone oxidative chain scission transformation through ozone catalytic oxidation, and has been transformed from a refractory high-molecular organic pollutant into another low-molecular organic matter with high degradability. The coordinate movement amount can be determined as the removal amount of COD and TOC according to experimental data, or determined as the increase amplitude of B / C. That is, the migration route of the coordinate migration can be quantified as a linear or nonlinear function. According to the process of the coordinate movement trajectory, the saturation degree of the ozone catalytic oxidation degree can be quantitatively analyzed. For example, when the actual detection result shows that the coordinates have not completely moved to the end point, it means that the actual ozone dosage is lower than the required amount, and then a signal to increase the ozone dosage is fed back to the ozone dosage controller. The disappearance situation is to monitor the attenuation degree of the intensity of the characteristic peak point. When the intensity of the fluorescence response characteristic peak of a main characteristic pollutant in the raw water decays from value C to value D, it means that the main characteristic pollutant in the raw water has undergone oxidation or mineralization through ozone catalytic oxidation, and the characteristic pollutant to be treated is completely oxidized to CO2 Or make it no longer show fluorescence, and the intensity attenuation degree can be determined as the removal amount of COD and TOC according to the actual experimental data. A linear or non-linear function relationship is established between the two. According to the fluorescence response characteristic peak intensity of the actually detected main characteristic pollutants, the values of COD and TOC are directly converted. It can conveniently feedback whether the ozone catalytic oxidation degree matches the designed COD or TOC removal amount. For example, if the detected fluorescence response characteristic peak intensity does not decay to the target value, it means that the actual ozone dosage is lower than the required amount, and then a signal to increase the ozone dosage is fed back to the ozone dosage controller. Characteristic fluorescence indices are generally divided into two categories. One is to extract the fluorescence intensity at a specific Ex / Em or within a range, which characterizes the content of fluorescent substances in the corresponding partition. The other is the integral ratio within a specific fluorescence range, which reflects the source, aromaticity, etc. of DOM. As a reference signal for detecting the ozone reaction degree, the latter is preferably selected, that is, the integral ratio within a specific fluorescence range. The selected index is the humification index (HIX), which is determined by fluorescence spectroscopy analysis technology. Specifically, it refers to the ratio of the integral of the fluorescence intensity in the wavelength ranges of 435 - 480 nm and 300 - 345 nm at an excitation wavelength of 254 nm. The magnitude of the humification index can reflect the source, composition, and humification degree of humus. When applied to the physical, chemical, and biochemical treatment processes of industrial wastewater, this index has a correlation with the complexity of pollutable components. The higher the index value, the higher the content of small molecule substances and the lower the aromaticity degree. Therefore, the specific value of the characteristic fluorescence index HIX can be determined through preliminary experiments for the degree of oxidation designed for the actual ozone catalytic oxidation system, that is, from the E value to the F value, where the F value is the oxidation design end point. According to the detected characteristic fluorescence index, it can conveniently feedback whether the ozone catalytic oxidation degree matches the designed COD or TOC removal amount. For example, if the detected characteristic fluorescence index is lower than the designed value, it means that the actual ozone dosage is lower than the required amount, and then a signal to increase the ozone dosage is fed back to the ozone dosage controller.

[0085] When the water quality detection device uses an ultraviolet spectrophotometer, the ultraviolet spectrophotometer adopts at least one of the spectral slopes S275 - 295 and S350 - 400. Among them, S275 - 295 and S350 - 400 are slope indices characterizing the characteristics of characteristic pollutants in water, which are the ultraviolet absorption slopes calculated in the wavelength ranges of 275 to 295 nanometers and 350 to 400 nanometers respectively. In this method, in addition to being used to establish a correlation with data such as COD and TOC, it can also be used to estimate the molecular size and aromaticity of pollutants, so it can also be used to establish a correlation with data such as BOD5 for biodegradability.

[0086] When the water quality detection device uses a pH meter or an ORP meter, the data detected and fed back by the pH meter or the ORP meter can be used to indicate the degree of ozone reaction. This method is different from the method of directly correlating three-dimensional fluorescence spectrum data and ultraviolet spectrum data with conventional water quality such as COD. Using the above data as the indication data signal for the actual operation of the ozone catalytic oxidation system, a reference relationship is established through pre-experiments between the changes in pH and ORP values of a specific wastewater after the ozone process and the changes in COD or TOC values after the ozone process.

[0087] The feed-back control mechanism is based on the condition that the water quality of the wastewater entering the ozone catalytic oxidation unit is relatively constant. Since the residence time of the wastewater in the ozone process from inlet to outlet is at least more than 0.5 h, the comparison of the inlet and outlet water quality information of the same meta-flow requires at least 0.5 h. The ozone catalytic oxidation process is a typical process with variable time delay and large inertia. If the applied working condition background is that the water quality of the wastewater entering the ozone catalytic oxidation unit often fluctuates greatly, relying solely on the water quality detection device to compare the information of the same meta-flow and then making a feed-back adjustment is prone to adjustment disorders. Therefore, a feed-forward control method is adopted for predictive compensation to achieve the adaptive adjustment of the ozone dosage, and the feed-back signal is used as a correction. Since the ozone catalytic oxidation process is a strict ratio control system, that is, for a specific wastewater treatment condition or the self-treatment ability of the process system, in order to achieve a certain removal amount of organic pollutants, a corresponding amount of ozone is required. Therefore, the flow signal serves as a ratio basis throughout the system. For example, when the influent flow rate changes greatly and exceeds the allowable fluctuation range set by the system, direct compensation is carried out according to the ratio between the real-time flow rate and the set flow rate.

[0088] In practical applications, the data correlation relationships established between three-dimensional fluorescence spectrum data and ultraviolet fluorescence data and conventional water quality parameters can provide analysis conditions for fluctuations in influent water quality. When the influent water quality fluctuates, pre-compensation can be carried out through the established data correlation relationships and the system operation OC ratio obtained from previous experiments, which can avoid feed-back adjustment disorders and achieve complete compensation for water quality fluctuations.

[0089] In the case of feed-back control, that is, when the influent water quality meets the set value (the threshold or threshold range set for the influent water quality) and the effluent water quality y(a) has an error deviation from the effluent set value r(a), then: (1) Set the detection frequency. For example, if the adjustment period is set to 10 min, the system takes data samples through the water quality detection device every 10 min. (2) Take 5% (for example) of the stable value (the effluent water quality set threshold or threshold range) as the allowable error range. The effluent water quality within a 5% fluctuation range is considered the allowable fluctuation range, and the system does not issue adjustment instructions within this range. (3) If the stable value is greater than 5%, the system warning will be triggered and recorded, and then a feedback signal will be sent to the ozone dosing controller. The ozone dosing controller determines whether the error value w(a) = y(a) - r(a) is positive or negative. If it is positive, the judgment conclusion is that positive compensation is required; if it is negative, the judgment conclusion is that negative compensation is required. (4) Determine the correlation relationship q(a) between the ozone dosing amount and the data signal detected by the (water quality detection device), and the correlation relationship q(h, k) between the ozone dosing amount and the frequency conversion amplitude h of the variable frequency power supply and the adjustment degree k of the oxygen inlet valve according to experiments. The ozone dosing controller first calculates the required compensated ozone dosing amount q1, and then judges whether to increase or decrease the power h1 of the variable frequency power supply. The adjustment amount is based on the relationship between the power supply power and the ozone concentration. If q1 deviates from the original preset initial value by a certain range (for example, 40%), a control signal will be output to the oxygen inlet valve to adjust the switch quantity k1 and adjust the oxygen flow to implement compound adjustment. (5) After adjustment, according to the continuous feedback adjustment, the result data is obtained cyclically to continuously correct the error of the system.

[0090] In the case of feedforward control, that is, when the influent water quality deviates from the set value and water quality fluctuations occur, and the influent water quality g(a) deviates from the influent set value d(a), then: (1) Set the detection frequency. For example, if the adjustment period is set to 10 minutes, the system will take a data sample through the water quality detection device every 10 minutes. (2) Take 5% (for example) of the stable value as the allowable error range. The effluent water quality within a 5% fluctuation range is considered the allowable fluctuation range, and no adjustment command is made to the system within this range. (3) If the stable value is greater than 5%, the system warning will be triggered and recorded, and then a feedback signal will be sent to the ozone dosing controller. The system starts the estimated compensation. The ozone dosing controller determines whether the error value w(a) = y(a) - r(a) is positive or negative. If it is positive, the judgment conclusion is that positive compensation is required; if it is negative, the judgment conclusion is that negative compensation is required. (4) Determine the correlation relationship q(a) between the ozone dosing amount and the data signal detected by the (water quality detection device), and the correlation relationship q(h, k) between the ozone dosing amount and the frequency conversion amplitude h of the variable frequency power supply and the adjustment degree k of the oxygen inlet valve according to experiments. The ozone dosing controller first calculates the required compensated ozone dosing amount q2, and then judges whether to increase or decrease the power h2 of the variable frequency power supply. The adjustment amount is based on the relationship between the power supply power and the ozone concentration. If q2 deviates from the original preset initial value by a certain range (for example, 40%), a control signal will be output to the oxygen inlet valve to adjust the switch quantity k2 and adjust the oxygen flow to implement compound adjustment. (5)All feedforward cases are for predictive compensation. The water quality detection signal r(a) at the end of the system after the residence time s1 is used as the output value to verify the feedback. After the adjustment in step (4), it is verified whether the function used for the feedback predictive compensation by r(a) is correct, and the correction calculation is started, that is, the compensation function F(w)=q(h,k)+C1. This correction may not be immediately fed back and implemented, but recorded by the system. The adjustment period can be set to 1 day or longer. Then, in the next adjustment period, the error compensation function is corrected to F(w)=q(h,k)+average(C).

[0091] The flow rate L signal is all for feedforward control and is directly adjusted according to the proportionality coefficient. When the influent L1 is greater than the designed value L0, the subsequent compensation function directly executes F(w)=L1 / L0 q(h,k).

[0092] The change threshold of the relevant variables on which the feedforward control is based can be set. For example, when the change (absolute change amplitude or absolute value of the relative change amplitude) of the relevant variables (measured values) exceeds the change threshold, the feedforward control is started, and the relevant parameters are adjusted by the feedforward control method. The value of the relevant variables when the feedforward control is started is used as the new standard value to judge the change amplitude of the measured value. When the change of the measured value with respect to the new standard value exceeds the change threshold, the feedforward control is started again. When the change amplitude of the measured value of the relevant variables on which the feedforward control is based with respect to the standard value does not exceed the change threshold, the feedback control is implemented. Therefore, the feedback control can be continuously implemented between two feedforward controls, and the feedback control is paused when the feedforward control is implemented.

[0093] The relevant variables on which the feedforward control is based can be the influent flow rate of pollutants (influent flow rate multiplied by pollutant concentration); in some scenarios (scenarios where the influent pollutant concentration is considered stable / has little change), the influent flow rate can be used as the relevant variable on which the feedforward control is based; in some scenarios (scenarios where the influent flow rate is considered stable / has little change), the pollutant concentration of the influent can be used as the relevant variable on which the feedforward control is based. The threshold of the absolute change amplitude of the relevant variables can be set. The so-called absolute change amplitude is the absolute value of the difference between the measured value and the standard value; the threshold of the relative change amplitude of the relevant variables can also be set. The so-called relative change is the quotient of the absolute change amplitude divided by the standard value (which can be calculated as a percentage). Thus, it can be considered that the feedforward control is a rough adjustment and the feedback control is a fine adjustment.

[0094] Example (taking the mixed wastewater of a certain pesticide production wastewater and a small amount of biological sewage as an example): Pretreatment of a certain pesticide wastewater. The raw water comes from the influent of a glyphosate herbicide production enterprise, mixed with a small amount of domestic sewage. The main technological purpose of the pretreatment section is to improve biodegradability and reduce COD. The technological sequence is the regulating tank, flocculation sedimentation tank, and ozone catalytic oxidation. The original water COD is about 230 mg / L, and the fluctuation range does not exceed 20%. After the flocculation sedimentation tank, the COD is about 210 mg / L, and the pH is stably about 9.0. The pilot experiment of the ozone catalytic oxidation process is carried out using the ozone catalytic oxidation system of the present invention. The designed COD removal amount in the pilot experiment is 100 mg / L. The selected influent flowmeter is an electromagnetic flowmeter, and the selected influent and effluent water quality monitor is a pH meter, with a pH measurement accuracy of 0.001. It has been verified by practice that the removal amount of COD and the change amount of pH of this sewage have a high correlation. Specifically, the total residence time is 1 h, the COD is reduced from 210 mg / L to 110 mg / L, and the corresponding pH is reduced from 9 to 8.4. Intermediate sampling is carried out, and the proportional band is set. The average COD in 0.5 h is 145, and the pH is 8.8. The actual COD and pH correlation relationship is more than 50 groups of data.

[0095] The automatic control of the ozone dosage is carried out in the form of feed-back control. The ozone dosage is controlled by controlling the ozone concentration, and the ozone concentration is adjusted by changing the output power of the variable-frequency power supply of the plate ozone generator. After setting by the background data, the system defaults the common influent flow rate to be 1 m 3 / h, and its corresponding initial power supply output power is 30% (the output power of 30% corresponds to an ozone concentration of about 56 mg / L).

[0096] There are two types of automatic control programs carried out successively: The first is to perform non-linear fitting. After the best fitting, the correlation relationship between △COD(y) and pH(x) finally obtained is: y=-103.18221exp(-x / 0.2012)+103.18204, x∈(8.2,9), y∈(90,246), R2=0.9786 The meaning expressed is that within the fitting range, the actual measured value of pH is used to replace COD for detection. If the COD value calculated from pH is lower than the pre-designed △COD(y), then according to the calculation of the mathematical function, the power supply output power is compensated. For every 5 mg / L shortage, 1% is compensated, and for every 5 mg / L surplus, 1% is reduced, and iterative calculation is carried out after 5 min.

[0097] The second method is that the actual control uses the change in pH value for compensation according to a preset ratio. Let the inlet pH value of the influent be a, and the outlet pH value (the effluent from the secondary ozone catalytic oxidation chamber) be b (a > b). During operation, a and b are read respectively, and b is the value after 1 hour (the residence time of the wastewater in the ozone catalytic oxidation unit is 1 hour), which are denoted as a1 and b1 respectively. The value of △pH = a1 - b1 is used as a reference value, denoted as c. After 5 minutes, the system automatically detects a and b again respectively, denoted as a2 and b2. Subtract c from the value of △pH = a2 - b2 (denoted as d). If the absolute value of d - c is less than 0.02, no adjustment is made. If d - c is less than -0.02, the power output of the power supply is increased by 1%. If d - c is greater than 0.02, the power output of the power supply is decreased by 1%. The upper and lower limits of the power output of the power supply are set to 20% - 50% respectively. If the upper and lower limits are exceeded, the operation is carried out according to the upper and lower limit conditions.

[0098] For each of the preferred and optional technical means disclosed in the present invention, except as otherwise specifically stated or when one preferred or optional technical means is a further limitation of another technical means, they can be combined arbitrarily to form several different technical solutions.

Claims

1. An ozone catalytic oxidation system with adaptive control of ozone dosage, characterized in that It comprises an ozone catalytic oxidation unit and an ozone dosing controller. The ozone catalytic oxidation unit is provided with a water inlet pipe, an air inlet pipe, a water outlet pipe and an air outlet pipe. The air inlet pipe is connected to an ozone generator. The ozone generator is provided with a variable frequency power supply. The water inlet pipe is provided with a flow meter and an inlet water quality detection device. The water outlet pipe is provided with an outlet water quality detection device. The detection signal outputs of the flow meter and each water quality detection device are connected to the ozone dosing controller. The control signal output of the ozone dosing controller is connected to the variable frequency power supply and the control end of the oxygen inlet valve of the ozone generator. The ozone dosing controller controls the ozone dosage of the ozone catalytic oxidation unit according to the comparison result of the water quality detection data before and after the wastewater treatment.

2. The ozone catalytic oxidation system for adaptively controlling ozone dosage according to claim 1 is characterized in that The inlet water quality detection device and the outlet water quality detection device are the same water quality detection device, and the water quality detection device is at least one of a three-dimensional fluorescence spectrometer, an ultraviolet spectrophotometer, a pH meter, and an ORP meter.

3. The ozone catalytic oxidation system for adaptively controlling ozone dosage according to claim 1, characterized in that The ozone catalytic oxidation unit is provided with an ozone catalytic oxidation chamber, which is provided with a water inlet, an air inlet, a water outlet and an air outlet, the water inlet and the air outlet are arranged at the top of the ozone catalytic oxidation chamber, the air inlet and the water outlet are arranged at the lower part of the ozone catalytic oxidation chamber, the ozone catalytic oxidation chamber is provided with a water distribution device connected with the water inlet, an air distribution device connected with the air inlet, a water outlet collecting device connected with the water outlet and a catalyst layer, the water distribution device is located at the upper part of the ozone catalytic oxidation chamber, the air distribution device and the water outlet collecting device are located at the lower part of the ozone catalytic oxidation chamber and the water outlet collecting device is located below the air distribution device, and the catalyst layer is located between the water distribution device and the air distribution device.

4. The ozone catalytic oxidation system for adaptively controlling ozone dosage according to claim 3 is characterized in that There are several ozone catalytic oxidation chambers, which are connected in sequence. The water outlet and the air outlet of the previous ozone catalytic oxidation chamber are respectively connected to the water inlet and the air inlet of the next ozone catalytic oxidation chamber, and the water inlet and the air inlet of the first ozone catalytic oxidation chamber are respectively connected to the water inlet pipe and the air inlet pipe.

5. The ozone catalytic oxidation system for adaptively controlling ozone dosage according to claim 3, characterized in that The air distribution device comprises an air distribution main pipe and a plurality of air distribution branch pipes cross-connected with the air distribution main pipe. The air distribution main pipe and each of the air distribution branch pipes are densely provided with microporous aerators.

6. The ozone catalytic oxidation system for adaptively controlling ozone dosage according to claim 3, characterized in that The water distribution device comprises a main water distribution pipe and a plurality of branch water distribution pipes cross-connected with the main water distribution pipe. The main water distribution pipe and each of the branch water distribution pipes are densely provided with water outlet holes inclined downward.

7. The ozone catalytic oxidation system for adaptively controlling ozone dosage according to claim 3, characterized in that The water outlet collection device comprises a water outlet main pipe and a plurality of water outlet branch pipes cross-connected with the water outlet main pipe. The water outlet main pipe and each of the water outlet branch pipes are densely provided with water inlet holes inclined downward.

8. The ozone catalytic oxidation system for adaptively controlling ozone dosage according to claim 1, characterized in that It also includes an exhaust gas circulation chamber and an exhaust gas destroyer, the exhaust gas circulation chamber is provided with a water inlet, an air inlet, a water outlet and an air outlet, the water inlet, the air inlet and the air outlet of the exhaust gas circulation chamber are arranged at the upper part thereof, the water outlet of the exhaust gas circulation chamber is arranged at the lower part thereof and is connected with a drain pipe, the outlet water quality detection device is arranged on the drain pipe, the water inlet and the air inlet of the exhaust gas circulation chamber are respectively connected with the water outlet pipe and the air outlet pipe of the ozone catalytic oxidation unit, the air outlet of the exhaust gas circulation chamber is connected with the air inlet of the exhaust gas destroyer through an exhaust pipe, a fan is arranged on the exhaust pipe, an air distribution device is arranged at the lower part of the exhaust gas circulation chamber, an exhaust gas circulation pipe is connected to the exhaust pipe between the fan and the exhaust gas destruction chamber, and the outlet of the exhaust gas circulation pipe is connected with the air distribution device of the exhaust gas circulation chamber.

9. The ozone catalytic oxidation system for adaptively controlling ozone dosage according to claim 1, characterized in that It also includes a wastewater pretreatment device, the water outlet of which is connected to the water inlet pipe of the ozone catalytic oxidation unit.

10. An ozone catalytic oxidation method for adaptively controlling ozone dosage, characterized in that An ozone catalytic oxidation system for adaptively controlling ozone dosage according to any one of claims 1 to 9 is adopted, wherein the ozone dosage controller determines whether the degree of ozone catalytic oxidation matches the removal amount of characteristic pollutants based on the real-time detection data of the flow meter and each water quality detection device; when they do not match, a compensation value of the ozone dosage is calculated based on the real-time detection data according to the pre-obtained correlation relationship between the ozone dosage and the detection data; then, based on the compensation value of the ozone dosage, the variable frequency power supply and the oxygen intake valve are controlled to perform corresponding operations in a feedback control and / or feedforward control manner according to the pre-obtained correlation relationship between the ozone dosage and the frequency conversion amplitude of the variable frequency power supply and the adjustment degree of the oxygen intake valve, so as to realize adaptive control of the ozone dosage.

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