A wastewater treatment system based on ultraviolet photocatalytic oxidation reaction

Abstract

The application discloses a wastewater treatment system based on ultraviolet photocatalytic oxidation reaction, comprising: a water inlet bucket for containing wastewater and adjusting the acid-base property of the wastewater by a first medicament tank; the wastewater in the water inlet bucket flows into a circulating mixing bucket; the circulating mixing bucket is communicated with a catalytic reaction module based on a pipeline mixer and a second medicament tank; the second medicament tank is used for adding an oxidant; the wastewater mixed by the pipeline mixer and the oxidant enter the catalytic reaction module; the catalytic reaction module is internally provided with an ultraviolet lamp for catalyzing and oxidizing the oxidant to be rapidly decomposed, so that the organic pollutants in the wastewater are efficiently oxidized and decomposed; part of the treated wastewater is discharged into a water outlet tank, and the other part of the treated wastewater is returned to the circulating mixing bucket through a heat exchange reflux unit. The controller realizes deep purification of organic wastewater with different concentrations and improves the wastewater purification effect by flexibly adjusting the water inlet amount, water outlet amount, oxidant adding amount and operation mode of the catalytic reaction module.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and specifically to a wastewater treatment system based on ultraviolet photocatalytic oxidation reaction. Background Technology

[0002] With the promotion of zero-discharge technology for industrial wastewater, membrane concentration technologies such as reverse osmosis and nanofiltration have been widely used for the reduction treatment of high-salinity and high-concentration wastewater. However, while concentrating wastewater, organic pollutants also accumulate in the membrane concentrate. If these enriched high-concentration, high-salinity, and recalcitrant organic compounds are directly introduced into the subsequent evaporation and crystallization unit without treatment, they are very likely to cause coking in the evaporator, reduce heat exchange efficiency, and seriously affect the purity of the crystallized salt, generating a large amount of hazardous waste containing mixed salts, significantly increasing the operating cost and disposal difficulty of the zero-discharge system.

[0003] Currently, advanced ozone oxidation, activated carbon adsorption, and electrocatalytic oxidation are commonly used technologies for the advanced treatment of such high-salinity and recalcitrant organic wastewater. Although advanced ozone oxidation is widely used, it suffers from low ozone utilization and limited selective oxidation of complex organic matter. Under conditions of salinity and complex water quality, its chemical oxygen demand (COD) removal rate is typically only around 10-20%, which is insufficient to meet the requirements for advanced treatment.

[0004] Activated carbon adsorption can effectively remove some organic matter, but it requires frequent replacement or regeneration after adsorption saturation, generating large amounts of hazardous waste and incurring extremely high regeneration costs. While electrocatalytic oxidation technology has certain advantages in treating high-salinity wastewater, high concentrations of corrosive components such as chloride ions drastically increase electrode wear, leading to high equipment investment and maintenance costs, thus limiting its large-scale engineering application. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a wastewater treatment system based on ultraviolet photocatalytic oxidation reaction, aiming to achieve deep purification of organic wastewater and improve wastewater purification efficiency by constructing an ultraviolet photocatalytic oxidation system.

[0006] This invention discloses a wastewater treatment system based on ultraviolet photocatalytic oxidation reaction, comprising: A water inlet tank is provided with a first pH monitor inside the water inlet tank. The water inlet tank is connected to a first reagent tank, which is used to add a first reagent into the water inlet tank. A circulating mixing tank is connected to the inlet tank. A second pH monitor and a temperature monitor are installed inside the circulating mixing tank. The circulating mixing tank is connected to a catalytic reaction module via a reaction pipe. A pipeline mixer is installed on the reaction pipe. An inlet pressure pump and an inlet flow monitor are installed between the pipeline mixer and the catalytic reaction module. The first inlet of the pipeline mixer is connected to the circulating mixing tank, and the second inlet of the pipeline mixer is connected to a second reagent tank, which is used to add oxidant into the reaction pipe. The inlet of the catalytic reaction module is connected to the outlet of the pipeline mixer to receive the mixed liquid. The catalytic reaction module is equipped with an ultraviolet lamp, and a water quality monitor and a return water flow monitor are installed at the first outlet of the catalytic reaction module. The heat exchange reflux unit has its inlet connected to the first outlet of the catalytic reaction module via a return water pressure pump, and its outlet connected to the circulating mixing tank, so as to exchange heat and cool part of the effluent after the catalytic reaction and reflux it back into the circulating mixing tank. A water outlet tank, which is connected to the second water outlet of the catalytic reaction module via a water outlet pipe; The controller is electrically connected to the first pH monitor, the second pH monitor, the temperature monitor, the catalytic reaction module, the water quality monitor, the first reagent tank, the second reagent tank, the inlet pressure pump, the return pressure pump, the heat exchange reflux unit, the return flow monitor, and the inlet flow monitor.

[0007] Preferably, the controller is configured as follows: The first reagent is added into the inlet tank by the first reagent tank so that the first pH value monitored by the first pH monitor is within the first preset range; The operating status of the inlet pressure pump and the return pressure pump is controlled so that the water quality parameters monitored by the water quality monitor are within a second preset range; The second reagent tank is controlled to add oxidant into the reaction tube so that the water quality parameters monitored by the water quality monitor are within the second preset range.

[0008] Preferably, the catalytic reaction module includes a first catalytic reactor and a second catalytic reactor, and the operation mode of the catalytic reaction module includes a parallel operation mode and a series operation mode; The reaction tube is equipped with multiple valves, and the controller is electrically connected to these valves to control the operating mode of the catalytic reaction module. The controller is configured such that if the water quality parameters are within the second preset range, the catalytic reaction module is controlled to operate in parallel mode; if the water quality parameters are not within the second preset range, the catalytic reaction module is controlled to operate in series mode.

[0009] Preferably, in the parallel operation mode, the inlet of the first catalytic reactor is connected to the circulating mixing tank via the first reaction pipe; the first reaction pipe is equipped with a first pipeline mixer and a first inlet pressure pump, the first inlet of the first pipeline mixer is connected to the circulating mixing tank, and the second inlet of the first pipeline mixer is connected to the second reagent tank. The inlet of the second catalytic reactor is connected to the circulating mixing tank via the second reaction pipe. The second reaction pipe is equipped with a second pipeline mixer and a second inlet pressure pump. The first inlet of the second pipeline mixer is connected to the circulating mixing tank, and the second inlet of the second pipeline mixer is connected to the second reagent tank. The first outlet of the first catalytic reactor and the first outlet of the second catalytic reactor are both connected to the inlet of the heat exchange reflux unit, and the second outlet of the first catalytic reactor and the second outlet of the second catalytic reactor are both connected to the outlet tank.

[0010] Preferably, in the series operation mode, the inlet of the first catalytic reactor is connected to the circulating mixing tank via the first reaction pipe; the first reaction pipe is equipped with a first pipeline mixer and a first inlet pressure pump, the first inlet of the first pipeline mixer is connected to the circulating mixing tank, and the second inlet of the first pipeline mixer is connected to the second reagent tank. The first outlet of the first catalytic reactor is connected to the inlet of the second catalytic reactor, the first outlet of the second catalytic reactor is connected to the inlet of the heat exchange reflux unit, and the second outlet of the second catalytic reactor is connected to the outlet tank.

[0011] Preferably, the first catalytic reactor and the second catalytic reactor have the same structure, both being a double-layer structure; The first catalytic reactor includes a reactor shell, with an ultraviolet lamp located at the center of the reactor shell. A quartz sleeve is fitted around the ultraviolet lamp, forming an annular water passage between the quartz sleeve and the reactor shell. The thickness of the water passage is within a preset thickness range, and the outer diameter of the quartz sleeve is within a preset outer diameter range.

[0012] Preferably, the water quality monitor includes a chemical oxygen demand (COD) monitor and a total organic carbon (TOC) analyzer; the water quality parameters include COD values ​​and TOC values. The chemical oxygen demand (COD) monitor is used to monitor COD values, and the total organic carbon (TOC) analyzer is used to monitor TOC values.

[0013] Preferably, the heat exchange reflux unit includes a plate heat exchanger, the hot side channel of which is connected in series between the first outlet of the catalytic reaction module and the circulating mixing tank, and the cold side channel of which is connected to an external cooling water source.

[0014] Preferably, the reactor shell is provided with a high borosilicate glass viewing window, and the reactor shell is provided with an irradiation intensity sensor, which is electrically connected to the controller.

[0015] Preferably, the wastewater treatment system based on ultraviolet photocatalytic oxidation reaction further includes a sewage discharge tank, which is connected to the inlet tank, the first reagent tank, the circulating mixing tank, the catalytic reaction module, the second reagent tank, and the heat exchange reflux unit via sewage discharge pipes; the sewage discharge pipes are equipped with multiple sewage discharge valves.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention regulates the pH of the wastewater in the inlet tank to a preset range using a first reagent tank, creating a suitable acidic environment for the subsequent catalytic reaction. The circulating mixing tank, via a second reagent tank, adds oxidant to the reaction tube. Through coordinated control of the inlet and return water pressure pumps, the ratio of inlet to return water flow is ensured to remain stable within a preset range, achieving efficient circulation of the mixture within the catalytic reaction module. The catalytic reaction module innovatively employs a combination design of a first and second catalytic reactor. Based on water quality parameters such as chemical oxygen demand (COD) and total organic carbon (TOC) values ​​fed back from the water quality monitor, it can intelligently switch between parallel and series operation modes, flexibly adapting to wastewater treatment needs with varying pollution loads. This achieves deep purification of organic wastewater. Attached Figure Description

[0017] Figure 1 A schematic diagram of the wastewater treatment system based on ultraviolet photocatalytic oxidation reaction provided by the present invention; Figure 2 A schematic diagram of the parallel operation mode of the catalytic reaction module provided by the present invention; Figure 3 This is a schematic diagram of the catalytic reaction module in series operation mode provided by the present invention.

[0018] Icon labels: 1. Inlet tank; 2. First reagent tank; 3. Circulating mixing tank; 4. Catalytic reaction module; 41. First catalytic reactor; 42. Second catalytic reactor; 5. Pipeline mixer; 6. Inlet pressure pump; 7. Second reagent tank; 8. Heat exchange reflux unit; 9. Return water pressure pump; 10. Outlet tank; 11. Valve. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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.

[0020] The present invention will now be described in further detail with reference to the accompanying drawings.

[0021] like Figure 1 As shown, this embodiment of the invention provides a wastewater treatment system based on ultraviolet photocatalytic oxidation, including an inlet tank 1. The inlet tank 1 is equipped with a first pH monitor, which monitors the pH value of the inlet water in real time and feeds the data back to a controller. The inlet tank 1 is connected to a first reagent tank 2, which adds a first reagent to the inlet tank 1. The first reagent can be an acidic or alkaline reagent, such as hydrochloric acid or sulfuric acid. The first reagent tank 2 may be equipped with a dosing pump, which is controlled by the controller. The controller controls the first reagent tank 2 to add the first reagent to the inlet tank 1, so that the first pH value monitored by the first pH monitor is within a first preset range. The first preset range corresponds to a pH value of 6 to 9; for example, the pH value can be selected as 6.5, 7.0, 7.5, or 8.0.

[0022] The circulating mixing tank 3 is connected to the inlet tank 1. For example, an inlet pump is installed between the circulating mixing tank 3 and the inlet tank 1. A second pH monitor and a temperature monitor are installed inside the circulating mixing tank to monitor the pH value and temperature of the mixture in real time and transmit the data to the controller. The circulating mixing tank 3 is connected to the catalytic reaction module 4 via a reaction tube. A pipeline mixer 5 is installed on the reaction tube. An inlet pressure pump 6 and an inlet flow monitor are installed between the pipeline mixer 5 and the catalytic reaction module 4. The first inlet of the pipeline mixer 5 is connected to the circulating mixing tank 3, and the second inlet of the pipeline mixer 5 is connected to the second reagent tank 7, which is used to add an oxidant into the reaction tube. For example, the oxidant can be hydrogen peroxide. A stirring device is installed inside the circulating mixing tank.

[0023] The pipeline mixer 5 can quickly and uniformly mix the wastewater transported by the circulating mixing tank 3 with the oxidant added by the second reagent tank 7, ensuring that the oxidant is evenly distributed in the wastewater and providing sufficient reaction conditions for the subsequent ultraviolet photocatalytic oxidation reaction. The inlet pressure pump 6 is used to provide power for the transport of wastewater from the circulating mixing tank 3 to the catalytic reaction module 4, and its operating parameters are adjusted by the controller according to the overall operating status of the system.

[0024] The inlet of the catalytic reaction module 4 is connected to the outlet of the pipe mixer 5 to receive the fully mixed mixture of oxidant and wastewater. The catalytic reaction module 4 is equipped with an ultraviolet lamp that emits ultraviolet light of a specific wavelength, serving as the light source for the catalytic oxidation reaction.

[0025] It should be noted that when ultraviolet light irradiates the mixed liquid, the high-intensity ultraviolet photocatalytic oxidant rapidly decomposes to produce a high concentration of active hydroxyl radicals, which can then efficiently oxidize and decompose organic pollutants in the wastewater, converting them into harmless substances such as carbon dioxide and water.

[0026] A water quality monitor and a return water flow monitor are installed at the first outlet of the catalytic reaction module 4. The water quality monitor can monitor the water quality parameters of the effluent after the catalytic reaction in real time. The water quality monitor includes a chemical oxygen demand (COD) monitor and a total organic carbon (TOC) analyzer. The COD monitor is used to monitor the COD value, and the TOC analyzer is used to monitor the TOC value. The water quality monitor feeds the monitoring data back to the controller, so that the controller can adjust the system operation according to the water quality conditions.

[0027] The inlet of the heat exchange reflux unit 8 is connected to the first outlet of the catalytic reaction module 4 via the return water pressure pump 9, and the outlet of the heat exchange reflux unit 8 is connected to the circulating mixing tank 3. Its function is to cool a portion of the effluent after the catalytic reaction and then return it to the circulating mixing tank 3. This returned effluent can mix with the newly introduced wastewater, which on the one hand dilutes the new wastewater, reducing its pollutant concentration and facilitating subsequent catalytic reactions; on the other hand, the cooled reflux liquid can regulate the temperature of the mixture in the circulating mixing tank 3, preventing the mixture temperature from becoming too high due to exothermic reactions, thus affecting the catalytic reaction efficiency or causing adverse effects on the equipment.

[0028] The return water pressure pump 9 provides power for the transport of the return liquid. It works in conjunction with the inlet water pressure pump 6, and under the control of the controller, maintains the ratio of inlet water flow to return water flow within a preset range to ensure stable system operation and treatment effectiveness. The controller controls the inlet and return water flow rates by controlling the operating states of the inlet and return water pressure pumps, thereby ensuring that the water quality parameters monitored by the water quality monitor are within a second preset range. The inlet and return water flow rates are collected by the inlet and return water flow monitors, respectively, and the preset ratio range of inlet water flow to return water flow rate is 1:11 to 1:23. In this way, the large reflux volume dilutes and mixes the influent, reduces the influent load, improves the system's resistance to shock loads, and ensures the flow rate of water in the reactor while increasing the water volume, thus improving the mixing reaction effect. On the other hand, the large reflux volume increases the influent volume and removes a large amount of heat generated by strong ultraviolet radiation during the reaction, reducing the temperature rise of the reaction liquid. At the same time, the reflux liquid enters the circulating mixing tank after heat exchange through the plate heat exchanger, ensuring the reactor influent temperature, avoiding reactor overheating, and improving operational safety.

[0029] The outlet tank 10 is connected to the second outlet of the catalytic reaction module 4 via an outlet pipe, and is used to collect the effluent that has undergone sufficient catalytic oxidation treatment and whose water quality parameters meet the preset discharge standards. This qualified effluent can be reused or discharged as needed.

[0030] The controller, as the core control unit of the entire system, is electrically connected to the first pH monitor, the second pH monitor, the temperature monitor, the catalytic reaction module 4, the water quality monitor, the first reagent tank 2, the second reagent tank 7, the inlet water pressure pump 6, the return water pressure pump 9, the heat exchange reflux unit 8, the return water flow monitor, and the inlet water flow monitor. The controller receives real-time data from each monitor, such as the pH value in the inlet tank 1, the pH value and temperature in the circulating mixing tank 3, and the water quality parameters of the effluent from the catalytic reaction module 4. Based on this data and the preset control strategy, the controller precisely controls the dosage of the first reagent tank 2, the oxidant dosage in the second reagent tank 7, the operating status of the inlet water pressure pump 6 and the return water pressure pump 9, and the working status of the catalytic reaction module 4.

[0031] The controller, based on water quality parameters collected by the water quality monitor, directs the addition of oxidant from the second reagent tank 7 into the reaction tube to increase the hydrogen peroxide concentration. Through this intelligent control method, the system achieves efficient, stable, and deep purification of organic wastewater.

[0032] In this embodiment of the invention, the heat exchange reflux unit 8 includes a plate heat exchanger. The hot side channel of the plate heat exchanger is connected in series between the first outlet of the catalytic reaction module 4 and the circulating mixing tank 3, and the cold side channel of the plate heat exchanger is connected to an external cooling water source.

[0033] In this way, the portion of the effluent whose temperature rises after the catalytic reaction flows through the hot side channel of the plate heat exchanger, where it undergoes efficient heat exchange with the external cooling water flowing in the cold side channel. This rapidly cools the high-temperature effluent to a suitable temperature for circulation, and then it is returned to the circulating mixing tank 3 by the return water pressure pump 9. For example, the inlet and outlet temperatures of the cold side channel of the plate heat exchanger are 30-35℃, and the inlet and outlet temperatures of the hot side channel are 39-35℃. The heat exchange plates of the plate heat exchanger are made of titanium, and the plate heat exchanger is supplied with cooling water via an external circulating cooling water or air heat source pump.

[0034] Plate heat exchangers offer advantages such as high heat exchange efficiency, compact structure, and small footprint, effectively meeting the system's heat exchange and cooling requirements while being easy to install and maintain. The external cooling water source can be selected from tap water, cooling tower circulating water, or other low-temperature water sources, depending on the actual situation, ensuring stable and reliable heat exchange performance.

[0035] In this embodiment of the invention, the wastewater treatment system based on ultraviolet photocatalytic oxidation reaction further includes a sewage discharge tank. The sewage discharge tank is connected to the inlet tank 1, the first reagent tank 2, the circulating mixing tank 3, the catalytic reaction module 4, the second reagent tank 7, and the heat exchange reflux unit 8 via sewage discharge pipes. Multiple sewage discharge valves are provided on the sewage discharge pipes.

[0036] The wastewater discharge tank is used to collect wastewater, cleaning water, and any abnormal discharges generated during system maintenance, repair, or reagent replacement, preventing these wastewaters from directly entering the environment and causing pollution. Each discharge valve is electrically connected to the controller, which can control the opening and closing of the corresponding discharge valves according to preset programs or manual commands, enabling periodic or emergency discharge. For example, when there is a large amount of sediment in the circulating mixing tank 3 or the water quality monitor detects abnormal water quality requiring emptying, the controller can open the valve on the corresponding discharge pipe to discharge the liquid into the wastewater discharge tank. The wastewater in the discharge tank can be collected and further treated according to its properties or handed over to a professional environmental protection agency for disposal, ensuring the environmental friendliness and safety of the entire wastewater treatment system.

[0037] In this embodiment of the invention, the catalytic reaction module 4 includes a first catalytic reactor 41 and a second catalytic reactor 42. The catalytic reaction module 4 can operate in parallel or in series. Multiple valves 11 are provided on the reaction tube, and a controller is electrically connected to these valves 11 to control the operating mode of the catalytic reaction module 4.

[0038] Specifically, if the water quality parameters are within the second preset range, the controller controls the operation mode of the catalytic reaction module 4 to be parallel operation mode; if the water quality parameters are not within the second preset range, the controller controls the operation mode of the catalytic reaction module 4 to be series operation mode.

[0039] In parallel operation mode, such as Figure 2As shown, the inlet of the first catalytic reactor 41 and the inlet of the second catalytic reactor 42 are both connected to the outlet of the pipeline mixer 5 via independent branch reaction pipes, so that the mixture of oxidant and wastewater after being mixed by the pipeline mixer 5 can enter the two catalytic reactors simultaneously for parallel treatment.

[0040] Specifically, the inlet of the first catalytic reactor 41 is connected to the circulating mixing tank 3 via a first reaction pipe; the first reaction pipe is equipped with a first pipeline mixer and a first inlet pressure pump, the first inlet of the first pipeline mixer is connected to the circulating mixing tank 3, and the second inlet of the first pipeline mixer is connected to the second reagent tank 7. The inlet of the second catalytic reactor 42 is connected to the circulating mixing tank 3 via a second reaction pipe, the second reaction pipe is equipped with a second pipeline mixer and a second inlet pressure pump, the first inlet of the second pipeline mixer is connected to the circulating mixing tank 3, and the second inlet of the second pipeline mixer is connected to the second reagent tank 7. The first outlet of the first catalytic reactor 41 and the first outlet of the second catalytic reactor 42 are both connected to the inlet of the heat exchange reflux unit 8, and the second outlets of the first catalytic reactor 41 and the second outlet of the second catalytic reactor 42 are both connected to the outlet tank 10.

[0041] It should be noted that in parallel operation mode, the first outlet of the first catalytic reactor 41 and the first outlet of the second catalytic reactor 42 are both connected to the inlet of the heat exchange reflux unit 8 via a connecting pipe, returning a portion of the treated mixture to the circulating mixing tank 3. Meanwhile, the second outlets of the first catalytic reactor 41 and the second outlets of the second catalytic reactor 42 are connected to the outlet tank 10 via a connecting pipe, collecting the treated water that meets the discharge standards into the outlet tank 10. In this parallel mode, the two catalytic reactors operate simultaneously, significantly increasing the system's treatment capacity. This mode is suitable for situations where water quality parameters (such as chemical oxygen demand and total organic carbon) are within a second preset range, i.e., the pollution load is relatively low and the treatment requirements are not extremely stringent. The increased treatment throughput meets the demand for high-efficiency treatment.

[0042] In the case of serial operation mode, such as Figure 3 As shown, the outlet of the first catalytic reactor 41 and the inlet of the second catalytic reactor 42 are connected by a connecting pipe to form a series treatment path. Specifically, the inlet of the first catalytic reactor 41 is connected to the circulating mixing tank 3 via a first reaction pipe. The first reaction pipe is equipped with a first pipeline mixer and a first inlet pressure pump 6. The first inlet of the first pipeline mixer is connected to the circulating mixing tank 3, and the second inlet of the first pipeline mixer is connected to the second reagent tank 7. The first outlet of the first catalytic reactor 41 is connected to the inlet of the second catalytic reactor 42, the first outlet of the second catalytic reactor 42 is connected to the inlet of the heat exchange reflux unit 8, and the second outlet of the second catalytic reactor 42 is connected to the outlet tank.

[0043] Thus, the mixture of oxidant and wastewater, after being mixed by the pipeline mixer 5, first enters the first catalytic reactor 41 for preliminary catalytic oxidation treatment. The treated mixture then enters the second catalytic reactor 42 for deep catalytic oxidation treatment. In series operation mode, the first outlet of the first catalytic reactor 41 can be selectively connected to the heat exchange reflux unit 8, or directly connected to the inlet of the second catalytic reactor 42. The first outlet of the second catalytic reactor 42 is connected to the inlet of the heat exchange reflux unit 8, and its second outlet is connected to the outlet tank 10.

[0044] In this series-connected mode, wastewater is treated sequentially through two catalytic reactors, which significantly extends the reaction time and improves the degradation efficiency of organic pollutants. This is suitable for situations where water quality parameters (such as chemical oxygen demand and total organic carbon) are outside the second preset range, i.e., when the pollution load is high, the content of recalcitrant organic matter is high, and treatment requirements are stringent. By enhancing the treatment depth, the effluent quality is ensured to meet standards. The controller intelligently switches between parallel and series operation modes of the first catalytic reactor 41 and the second catalytic reactor 42 by controlling the opening and closing of the corresponding valves 11 on the reaction pipe. This allows for flexible response to treatment needs under different water quality conditions, optimizing treatment effectiveness and operating costs.

[0045] In this embodiment of the invention, the first catalytic reactor 41 and the second catalytic reactor 42 have the same structure, both being double-layered structures. The first catalytic reactor 41 includes a reactor shell, with an ultraviolet lamp located at the center of the reactor shell. A quartz sleeve is fitted around the ultraviolet lamp, forming an annular water passage between the quartz sleeve and the reactor shell. The thickness of the water passage is within a preset thickness range, and the outer diameter of the quartz sleeve is within a preset outer diameter range. The preset thickness range of the water passage is 10-20 mm, the preset outer diameter range of the quartz sleeve is 30-40 mm, and the water flow velocity in the water passage is controlled at 0.7~2 m / s.

[0046] For example, the ultraviolet lamp is preferably a high-power, high-intensity irradiation medium-pressure mercury lamp with a wavelength range of 0-400nm, and preferably a single lamp with a power of 6kW or 12kW; the strong ultraviolet photocatalytic oxidation reactor can automatically achieve series and parallel operation through valve 11 and pipeline switching, and the operation mode can be flexibly adjusted.

[0047] The mass ratio of oxidant to wastewater COD should be in the range of (2~10):1, and the ratio of oxidant to TOC should be (6-30):1. The reaction time under a single ultraviolet irradiation should be controlled within 180s to prevent the reaction solution from overheating.

[0048] By controlling the outer diameter of the quartz sleeve within the range of 30-40mm, the distance between the sleeve and the lamp tube can be reduced, effectively promoting heat dissipation from the lamp source. A water-passing layer exists between the quartz sleeve and the reactor shell, with a thickness controlled within the range of 10-20mm and a flow velocity of 0.7~2m / s. The reactor adopts a thin-layer water-passing structure. By reducing the thickness of the water-passing layer, the irradiation intensity of the wastewater in the layer is increased, enhancing the treatment effect. Simultaneously, the thin water layer ensures a high flow velocity, improving the scouring of the sleeve surface, reducing lamp tube scaling, and lowering the cleaning frequency. The catalytic reaction module 4 is made of duplex steel such as 2205 or 2507, or 316L with a fluorine coating, to avoid corrosion from high-salt, high-chlorine wastewater.

[0049] In this embodiment of the invention, a high borosilicate glass window is provided on the reactor shell for observing the reaction state, and an irradiation intensity sensor is provided inside the reactor shell. The irradiation intensity sensor is electrically connected to the controller for monitoring the temperature and the intensity of the strong ultraviolet lamp irradiation.

[0050] In this embodiment of the invention, the controller acquires temperature data sent by the temperature monitor in the circulating mixing tank 3. When the temperature exceeds the warning value, it promptly adjusts the cooling water flow of the cooling system to reduce the outlet water temperature. When the temperature exceeds the over-limit setting value, it turns off the ultraviolet lamp to prevent the strong ultraviolet lamp from overheating and going out, thus ensuring the safe operation of the system.

[0051] The following is a detailed explanation of a wastewater treatment system based on ultraviolet photocatalytic oxidation, illustrated by a specific example. The membrane concentrate has a TDS of 50,000-150,000 mg / L and a COD of 100-1000 mg / L. The specific treatment process is as follows: Wastewater is first temporarily stored in inlet tank 1, and the pH value of the wastewater is measured using a first pH monitor and is within the range of 6-9. If the pH is outside the range, acid and alkali are added through the first reagent tank 2 to adjust the pH. The pH-adjusted wastewater enters the circulating mixing tank 3, and the wastewater in the circulating mixing tank 3 enters the first catalytic reactor and the second catalytic reactor through the first reaction pipe and the second reaction pipe, respectively. The reaction pipe is equipped with a pipeline mixer and an inlet pressure pump. The pipeline mixer is connected to the second reagent tank 7 to mix hydrogen peroxide with the membrane concentrate. The hydrogen peroxide dosage is 400-2000 mg / L.

[0052] The controller controls the flow rate of wastewater from the inlet tank 1 into the circulating mixing tank 3 to be one cubic meter per hour, while the inlet pressure pump operates at a flow rate of 12 cubic meters per hour. After mixing with the wastewater, hydrogen peroxide enters the catalytic reaction module 4. Within the thin-layer flow path, the hydrogen peroxide in the wastewater undergoes catalytic decomposition under high-intensity ultraviolet (UV) irradiation, generating hydroxyl radicals. These hydroxyl radicals oxidize and decompose recalcitrant organic matter in the water, achieving deep COD removal. The UV lamp tube length is controlled to approximately 800-1000 mm, and the diameter to be within the range of 80-90 mm. The diameter of the quartz sleeve surrounding the UV lamp is within the range of 30-40 mm, and the flow passage is within the range of 10-20 mm, ensuring the flow velocity is controlled within 0.7-2.5 m / s to prevent excessive wastewater temperature rise.

[0053] After the reaction in catalytic reaction module 4, one stream of water (1 cubic meter per hour) enters the water outlet tank, and another stream (23 cubic meters per hour) enters the circulation pipeline and then enters the plate heat exchanger for heat exchange and cooling. After cooling, the water returns to the circulating mixing tank.

[0054] The reactor effluent enters the effluent tank, and the COD / TOC data is monitored online. If the COD / TOC does not meet the requirements, the controller adjusts the valve 11 of the catalytic reaction module 4 to realize the series operation of the first catalytic reactor 41 and the second catalytic reactor 42. After continuous reaction, part of the effluent enters the effluent tank 10, and the remaining effluent enters the circulation pipeline. After heat exchange by the plate heat exchanger, it returns to the circulation mixing tank 3, mixes with the influent, and then enters the reactor again for reaction, realizing multiple circulation reactions and improving the treatment effect.

[0055] As can be seen from the above technical solution, this application provides a wastewater treatment system based on ultraviolet photocatalytic oxidation reaction. By setting up a circulating mixing tank and a catalytic reaction module to form a circulating treatment path, and introducing a heat exchange reflux unit to cool part of the effluent before recirculation, effective dilution and temperature control of the influent are achieved, improving the system's resistance to shock loads and operational safety. At the same time, the controller intelligently controls the reagent addition, flow ratio, and catalytic reaction module operation mode (series / parallel) based on real-time monitoring data. Combined with the double-layer catalytic reactor design, the ultraviolet photocatalytic oxidation efficiency is significantly improved, ensuring that wastewater with different pollution loads can achieve efficient and stable deep purification treatment, thereby improving the wastewater purification effect.

[0056] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A wastewater treatment system based on ultraviolet photocatalytic oxidation reaction, characterized in that, include: A water inlet tank is provided with a first pH monitor inside the water inlet tank. The water inlet tank is connected to a first reagent tank, which is used to add a first reagent into the water inlet tank. A circulating mixing tank is connected to the inlet tank. A second pH monitor and a temperature monitor are installed inside the circulating mixing tank. The circulating mixing tank is connected to a catalytic reaction module via a reaction pipe. A pipeline mixer is installed on the reaction pipe. An inlet pressure pump and an inlet flow monitor are installed between the pipeline mixer and the catalytic reaction module. The first inlet of the pipeline mixer is connected to the circulating mixing tank, and the second inlet of the pipeline mixer is connected to a second reagent tank, which is used to add oxidant into the reaction pipe. The inlet of the catalytic reaction module is connected to the outlet of the pipeline mixer to receive the mixed liquid. The catalytic reaction module is equipped with an ultraviolet lamp. A water quality monitor and a return water flow monitor are installed at the first outlet of the catalytic reaction module. The catalytic reaction module includes a first catalytic reactor and a second catalytic reactor. The catalytic reaction module can operate in parallel and in series. A heat exchange reflux unit is provided, wherein the inlet of the heat exchange reflux unit is connected to the first outlet of the catalytic reaction module via a return water pressure pump, and the outlet of the heat exchange reflux unit is connected to the circulating mixing tank, so as to exchange heat and cool part of the effluent after the catalytic reaction and reflux it back into the circulating mixing tank; the heat exchange reflux unit includes a plate heat exchanger, the hot side channel of which is connected in series between the first outlet of the catalytic reaction module and the circulating mixing tank, and the cold side channel of which is connected to an external cooling water source; A water outlet tank, which is connected to the second water outlet of the catalytic reaction module via a water outlet pipe; The controller is electrically connected to the first pH monitor, the second pH monitor, the temperature monitor, the catalytic reaction module, the water quality monitor, the first reagent tank, the second reagent tank, the inlet pressure pump, the return pressure pump, the heat exchange reflux unit, the return flow monitor, and the inlet flow monitor, respectively. The reaction tube is equipped with multiple valves, and the controller is electrically connected to multiple valves to control the operating mode of the catalytic reaction module.

2. The wastewater treatment system based on ultraviolet photocatalytic oxidation reaction according to claim 1, characterized in that, The controller is configured to: The first reagent is added into the water inlet tank by the first reagent tank, so that the first pH value monitored by the first pH monitor is within a first preset range; The operating status of the inlet pressure pump and the return pressure pump is controlled so that the water quality parameters monitored by the water quality monitor are within a second preset range; The second reagent tank is controlled to add the oxidant into the reaction tube so that the water quality parameters monitored by the water quality monitor are within a second preset range.

3. The wastewater treatment system based on ultraviolet photocatalytic oxidation reaction according to claim 2, characterized in that, The controller is configured to: if the water quality parameters are within the second preset range, control the operation mode of the catalytic reaction module to be parallel operation mode; if the water quality parameters are not within the second preset range, control the operation mode of the catalytic reaction module to be series operation mode.

4. The wastewater treatment system based on ultraviolet photocatalytic oxidation reaction according to claim 3, characterized in that, In the parallel operation mode, the inlet of the first catalytic reactor is connected to the circulating mixing tank via the first reaction pipe; the first reaction pipe is equipped with a first pipeline mixer and a first inlet pressure pump, the first inlet of the first pipeline mixer is connected to the circulating mixing tank, and the second inlet of the first pipeline mixer is connected to the second reagent tank. The inlet of the second catalytic reactor is connected to the circulating mixing tank via the second reaction pipe. The second reaction pipe is equipped with a second pipeline mixer and a second inlet pressure pump. The first inlet of the second pipeline mixer is connected to the circulating mixing tank, and the second inlet of the second pipeline mixer is connected to the second reagent tank. The first outlet of the first catalytic reactor and the first outlet of the second catalytic reactor are both connected to the inlet of the heat exchange reflux unit, and the second outlet of the first catalytic reactor and the second outlet of the second catalytic reactor are both connected to the outlet tank.

5. The wastewater treatment system based on ultraviolet photocatalytic oxidation reaction according to claim 3, characterized in that, In the series operation mode, the inlet of the first catalytic reactor is connected to the circulating mixing tank via the first reaction pipe; the first reaction pipe is equipped with a first pipeline mixer and a first inlet pressure pump, the first inlet of the first pipeline mixer is connected to the circulating mixing tank, and the second inlet of the first pipeline mixer is connected to the second reagent tank. The first outlet of the first catalytic reactor is connected to the inlet of the second catalytic reactor, the first outlet of the second catalytic reactor is connected to the inlet of the heat exchange reflux unit, and the second outlet of the second catalytic reactor is connected to the outlet tank.

6. The wastewater treatment system based on ultraviolet photocatalytic oxidation reaction according to claim 3, characterized in that, The first catalytic reactor and the second catalytic reactor have the same structure, both being a double-layer structure; The first catalytic reactor includes a reactor shell, with an ultraviolet lamp located at the center of the reactor shell. A quartz sleeve is fitted around the ultraviolet lamp, and an annular water passage is formed between the quartz sleeve and the reactor shell. The thickness of the water passage is within a preset thickness range, and the outer diameter of the quartz sleeve is within a preset outer diameter range.

7. The wastewater treatment system based on ultraviolet photocatalytic oxidation reaction according to claim 1, characterized in that, The water quality monitor includes a chemical oxygen demand (COD) monitor and a total organic carbon (TOC) analyzer; the water quality parameters include COD values ​​and TOC values. The chemical oxygen demand (COD) monitor is used to monitor the COD value, and the total organic carbon (TOC) analyzer is used to monitor the TOC value.

8. The wastewater treatment system based on ultraviolet photocatalytic oxidation reaction according to claim 6, characterized in that, The reactor shell is provided with a high borosilicate glass viewing window, and the reactor shell is provided with an irradiation intensity sensor, which is electrically connected to the controller.

9. The wastewater treatment system based on ultraviolet photocatalytic oxidation reaction according to claim 1, characterized in that, It also includes a sewage tank, which is connected to the water inlet tank, the first reagent tank, the circulating mixing tank, the catalytic reaction module, the second reagent tank and the heat exchange reflux unit via sewage pipes; the sewage pipes are equipped with multiple sewage valves.

Images