Photocatalytic oxidation treatment system and method for non-biodegradable organic wastewater

Abstract

The invention provides a photocatalytic oxidation treatment system and method for non-biodegradable organic wastewater, relates to the field of photocatalytic water treatment, and aims to solve the problem of low light energy utilization efficiency during photocatalytic oxidation treatment of wastewater in the prior art. The rotational flow guide grooves force fluid to generate strong rotational flow along the surface of the protective cover, a laminar flow boundary layer retarding mass transfer is actively damaged, and the contradiction that the flow speed is low at the strong illumination position is solved; a scattering / refraction interface formed by the grooves and the convex edges physically expands the contact area of a light source and wastewater, prolongs the optical path of ultraviolet light in a medium and increases the probability that photons are captured by pollutants; and the viscous attachments which are difficult to remove at the conventional smooth flow velocity are effectively stripped by utilizing instantaneous high shearing force generated by interaction of pulse backwashing water flow and the rib structure, so that the interface mass transfer efficiency and the organic matter degradation rate of unit light energy are improved on the premise of maintaining long-term high light transmittance of equipment, and the light energy utilization rate is improved.

Description

Technical Field

[0001] This invention relates to the field of photocatalytic water treatment, specifically to a photocatalytic oxidation treatment system and method for recalcitrant organic wastewater. Background Technology

[0002] Recalcitrant organic wastewater is generally characterized by complex composition, high biotoxicity, and poor biodegradability, making it a key target for industrial wastewater treatment. Photocatalytic oxidation technology, as a highly efficient advanced oxidation process, effectively disrupts the stable structure of organic macromolecules by generating strong oxidizing hydroxyl radicals under ultraviolet light excitation, achieving deep mineralization or modification of pollutants. Among existing technologies, the tubular photocatalytic reactor has become the mainstream form due to its compact structure and ease of engineering application. Its basic structure typically includes a centrally located tubular light source and a transparent protective shell enclosing the light source. Wastewater flows within the annular channel formed between the protective shell and the outer shell, undergoing photochemical reactions.

[0003] However, in actual operation, the light energy utilization efficiency of existing sleeve-type photocatalytic treatment systems is limited by the lack of a physical field synergy mechanism, and there are still insurmountable technical problems. Specifically, the casing of traditional light sources is mostly a smooth cylindrical surface. When fluid flows over its surface, a stable laminar boundary layer is easily generated. Due to the rapid exponential decay of ultraviolet light in industrial wastewater, the peak light intensity is highly concentrated in a micro-region close to the surface of the casing. The interfacial mass transfer resistance caused by the laminar boundary layer results in a low fluid renewal rate in this region. As a result, the light energy in the high-intensity region is excessively consumed in the degraded fluid, while the pollutants in the main fluid are difficult to effectively enter the reaction zone. The smooth interface of the light source casing lacks an optical scattering mechanism, resulting in a short optical path. Furthermore, for the stubborn scaling problem of high-viscosity wastewater, conventional hydraulic flushing is insufficient to remove the deposits, leading to an irreversible decrease in transmittance and making it difficult to effectively improve the reaction rate per unit of light energy. Summary of the Invention

[0004] In view of this, the present invention provides a photocatalytic oxidation treatment system and method for recalcitrant organic wastewater, which improves light energy utilization efficiency, disrupts the laminar boundary layer to promote fluid dynamic renewal, slows down the accumulation of dirt and maintains light transmittance, and achieves efficient and stable pollutant treatment.

[0005] The first objective of this invention is to provide a photocatalytic oxidation treatment system for recalcitrant organic wastewater, employing the following approach: It includes an outer shell and a light source. The light source is covered with a cylindrical light source shield, which extends into the outer shell. A reaction chamber with a radial cross-section of annular is formed between the light source shield and the inner wall of the inner cavity of the outer shell. The reaction chamber is provided with inlet and outlet water outlets that are spaced apart along the axial direction. The outer circumferential surface of the light source shield is provided with spirally distributed grooves and ridges, which form the optical scattering / refractive interface of the light source and expand the contact area between the light source and the wastewater in the reaction chamber. The grooves and ridges form a swirling flow guide groove on the outer circumferential surface of the light source shield, and its spiral angle matches the cutting angle of the inlet. The end face of the reaction chamber is provided with a pulse backwash port to output pulse backwash water flow to disturb the outer circumferential surface of the light source shield.

[0006] Furthermore, the pulse backwash port is connected to a nozzle facing the reaction chamber, and the pulse backwash port is connected to an external pulse water source.

[0007] Furthermore, the pulse backwash port is located at one end of the reaction chamber near the water outlet.

[0008] Furthermore, the grooves and ridges are distributed alternately in sequence, and adjacent ridges and the grooves between them together form a swirling guide groove.

[0009] Furthermore, a spiral guide vane is provided on the inner wall of the outer shell, and the spiral guide vane has the same rotation direction as the swirling guide groove.

[0010] Furthermore, the inlet and outlet are connected through a circulation pipe outside the casing. The circulation pipe is coupled with a heat exchanger to exchange heat with the wastewater inside the circulation pipe, and a circulation water pump is installed on the circulation pipe.

[0011] Furthermore, a temperature sensor is installed inside the reaction chamber. The temperature sensor, the circulating water pump, and the heat exchanger are respectively connected to the controller. The temperature sensor is used to measure the temperature of the wastewater in the reaction chamber and send it to the controller. The controller is used to adjust the operating status of the circulating water pump and the heat exchanger.

[0012] Furthermore, the outer casing is provided with an observation port and an instrument mounting port, and the light source cover is made of transparent material, which isolates the light source from the reaction chamber.

[0013] A second objective of this invention is to provide a method for operating a photocatalytic oxidation treatment system for recalcitrant organic wastewater, utilizing the photocatalytic oxidation treatment system for recalcitrant organic wastewater as described in the first objective, comprising: Wastewater enters tangentially through the inlet and is guided by the spirally distributed swirling guide grooves on the outer circumference of the light source shield, generating a strong swirling flow that matches the inlet angle, breaking the laminar boundary layer on the surface of the light source shield, and renewing the fluid that is in close contact with the light source shield. The light source emits ultraviolet light, which passes through the shield and enters the reaction chamber. The grooves and protrusions on the surface of the shield serve as an optical scattering / refractive interface, expanding the contact area between the light source and the wastewater. This allows the wastewater, which is in a highly turbulent state, to capture more light energy and efficiently oxidize and decompose organic matter. The pulse backwash port outputs a pulsed water flow, which uses instantaneous impact force to directly disturb the outer circumference of the light source cover, peeling off the dirt deposited on the grooves and protrusions, and restoring light transmittance.

[0014] Furthermore, the temperature of the wastewater injected into the reaction chamber is measured, and the wastewater flow rates at the inlet and outlet are adjusted.

[0015] Compared with the prior art, the advantages and positive effects of this invention are: To address the low light energy utilization efficiency in existing photocatalytic oxidation wastewater treatment technologies, this invention constructs a synergistic enhancement mechanism for flow field, light field, and cleaning by incorporating spirally distributed grooves and ridges on the outer circumference of the light source shield, matched with the inlet water inlet angle, and combined with pulse backwashing ports. In terms of fluid dynamics, the swirling guide grooves force the fluid to generate strong swirling flow along the shield surface, actively disrupting the laminar boundary layer that hinders mass transfer, resulting in a dramatic fluid renewal in high-intensity areas and resolving the contradiction of slow flow velocity in areas of high light intensity. Optically, the scattering / refractive interface formed by the grooves and ridges physically expands the contact area between the light source and the wastewater, extends the optical path of ultraviolet light in the medium, and increases the probability of photons being captured by pollutants. In terms of cleaning and maintenance, the instantaneous high shear force generated by the interaction between the pulse backwash water flow and the ridge structure effectively removes sticky deposits that are difficult to remove with conventional smooth flow rates. These mechanisms work together to improve interface mass transfer efficiency and the rate of organic matter degradation per unit of light energy while maintaining high light transmittance of the equipment over a long period, thereby enhancing light energy utilization.

[0016] A dual-sided synergistic flow field constraint mechanism is constructed, in which the spiral guide vanes on the outer wall and the swirling guide grooves on the inner light source shield form a fluid channel in the same direction, forcing the fluid in the entire annular cavity to maintain a consistent rotational motion, preventing the fluid from short-circuiting through areas with low resistance, reducing the dead zone of the flow velocity in the reaction chamber, and increasing the tangential velocity component of the fluid. This enhances the centrifugal force's pressing effect and shear scouring effect on the shield surface, achieving continuous cleaning and efficient mass transfer of the photocatalytic interface throughout the entire reaction process.

[0017] For high-viscosity, highly adhesive organic dirt, the technical challenge of effectively removing it by simply relying on water flooding or low-speed backwashing is addressed by utilizing the energy focusing of the nozzle and the unsteady impact effect of the pulse source. This converts the static pressure potential energy of the external water source into a high-velocity kinetic energy jet directed towards the surface of the light source cover. Pressure fluctuations are generated near the nozzle outlet, where dirt tends to accumulate. This generates instantaneous physical impact and peeling force on stubborn dirt attached to tiny grooves or sharp corners, achieving deep cleaning. The optical transparency of the quartz cover is restored without disassembling the equipment, reducing equipment maintenance costs and downtime.

[0018] By using a heat exchanger to force heat exchange in the circulating fluid, the thermodynamic environment of the reaction system is precisely controlled. Combined with a circulating pump, the material is repeatedly refluxed and irradiated. This maintains the ultraviolet lamps operating within the temperature range of optimal photoelectric conversion efficiency, preventing overheating and cracking or spectral drift. Furthermore, by accumulating reaction time, the effective irradiation time is increased, achieving deep treatment of difficult-to-decompose organic compounds such as benzene rings and heterocyclic compounds, and ensuring the stability of the final effluent water quality. Attached Figure Description

[0019] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0020] Figure 1 This is a schematic diagram of a photocatalytic oxidation treatment system for recalcitrant organic wastewater in one or more embodiments of the present invention.

[0021] Figure 2 This is a schematic diagram of the water inlet connecting to the outer casing in one or more embodiments of the present invention.

[0022] The components are as follows: 1. Outer shell; 2. Light source; 3. Light source cover; 4. Reaction chamber; 5. Inlet; 6. Outlet; 7. Groove; 8. Protrusion; 9. Swirl guide channel; 10. Pulse backwash port; 11. Heat exchanger; 12. Circulation pipe; 13. Circulation water pump; 14. Observation port; 15. Instrument mounting port. Detailed Implementation

[0023] Example 1 In a typical embodiment of the present invention, such as Figures 1-2 As shown, a photocatalytic oxidation treatment system for recalcitrant organic wastewater is presented.

[0024] Existing tubular photocatalytic treatment systems for treating recalcitrant organic wastewater suffer from several drawbacks, including low light energy utilization efficiency, high fluid mass transfer resistance, slow fluid renewal rate in high-intensity light zones, difficulty in effectively introducing pollutants into the reaction zone, short optical path length due to the scattering mechanism of the light source's casing, and persistent scaling issues with high-viscosity wastewater, where conventional hydraulic flushing is insufficient to remove deposits, leading to irreversible degradation of transmittance and hindering the effective improvement of the reaction rate per unit of light energy. Therefore, this embodiment provides a photocatalytic oxidation treatment system for recalcitrant organic wastewater, which offers advantages such as improved light energy utilization efficiency, disruption of the laminar boundary layer to promote dynamic fluid renewal, prevention of fouling accumulation to maintain transmittance, and efficient and stable pollutant treatment.

[0025] like Figures 1-2As shown, the photocatalytic oxidation treatment system for recalcitrant organic wastewater includes an outer shell 1 and a light source 2. The light source 2 is covered with a cylindrical light source cover 3, which extends into the outer shell 1. A reaction chamber 4 with a radial cross-section of annular is formed between the light source cover 3 and the inner wall of the inner cavity of the outer shell 1. The reaction chamber 4 is provided with an inlet 5 and an outlet 6 that are spaced apart along the axial direction. The outer circumferential surface of the light source cover 3 is provided with spirally distributed grooves 7 and protrusions 8, which constitute the optical scattering / refractive interface of the light source 2 and expand the contact area between the light source 2 and the wastewater in the reaction chamber 4. The grooves 7 and protrusions 8 form a swirling flow guide groove 9 on the outer circumferential surface of the light source cover 3, and its spiral angle matches the cutting angle of the inlet 5. The end face of the reaction chamber 4 is provided with a pulse backwash port 10 to output pulse backwash water flow to disturb the outer circumferential surface of the light source 2.

[0026] The light source 2 is encased in a cylindrical light source cover 3, made of transparent quartz. The light source 2 is an ultraviolet lamp, and the light source cover 3 carries the light source 2 inside the outer casing 1. A radially annular reaction chamber 4 is formed between the light source cover 3 and the inner wall of the inner cavity of the outer casing 1. This reaction chamber 4 is the main site for the photocatalytic reaction of wastewater. To achieve continuous wastewater treatment, the reaction chamber 4 is provided with an inlet 5 and an outlet 6 spaced apart along the axial direction. Wastewater enters the reaction chamber 4 through the inlet 5 and is discharged from the outlet 6 after treatment. The light source cover 3 can adopt a columnar shell structure to isolate the light source 2 from the wastewater. The inlet 5 and outlet 6 can be connected to the reaction chamber 4 by pipes, allowing wastewater to enter and exit the reaction chamber 4.

[0027] The grooves 7 and ridges 8 on the outer circumferential surface of the light source shield 3 together constitute the optical scattering and refraction interface of the light source 2. Increasing the grooves 7 and ridges 8 expands the contact area between the light source 2 and the wastewater in the reaction chamber 4, thereby improving the utilization efficiency of light energy. Simultaneously, the grooves 7 and ridges 8 also form a swirling flow guide groove 9 on the outer circumferential surface of the light source shield 3, used to guide the wastewater to form a specific flow pattern within the reaction chamber 4. The helix angle of this swirling flow guide groove 9 matches the inlet angle of the inlet 5 to optimize the fluid dynamics effect. In this embodiment, the surface of the light source shield 3 can be designed with an alternating structure of grooves 7 and ridges 8, and the cross-sections of the grooves 7 and ridges 8 can be V-shaped to provide an optical scattering effect.

[0028] The pulse backwash port 10 is used to output a pulse backwash water flow into the reaction chamber 4 to agitate the outer circumferential surface of the light source shield 3, thereby periodically cleaning the surface of the light source shield 3 to remove dirt adhering to it and maintain its light transmission performance. The pulse backwash port 10 can be a simple opening, with a continuous water flow provided by an external water pump for rinsing.

[0029] This system constructs an optical scattering and refraction interface and a swirling flow guide channel 9 by setting spiral grooves 7 and protrusions 8 on the outer circumferential surface of the light source shield 3. This effectively expands the contact area between the light source 2 and the wastewater, forces the wastewater to form a strong swirling flow, disrupts the laminar boundary layer, and improves mass transfer efficiency, solving the problems of low light energy utilization and limited mass transfer in traditional systems. Simultaneously, a pulse backwash port 10 is provided, which outputs pulsed water flow to directly disturb the shield surface, effectively removing attached dirt and restoring light transmittance. This overcomes the difficulty of cleaning stubborn scale using traditional hydraulic flushing, thereby improving the photocatalytic oxidation treatment efficiency and system operational stability of recalcitrant organic wastewater.

[0030] like Figure 1 As shown, the pulse backwash port 10 is connected to a nozzle facing the reaction chamber 4, and the pulse backwash port 10 is connected to an external pulse water source. The nozzle outlet faces the interior of the reaction chamber 4, particularly the outer circumferential surface of the light source shield 3. The nozzle structure may include a converging section, a throat, and a diffuser section. Through its internal flow channel design, it can accelerate the incoming pulse water flow and form a jet with high velocity and impact force. This jet can precisely act on the surface of the light source shield 3, providing concentrated physical impact force to effectively remove dirt adhering to the shield. The nozzle can be made of corrosion-resistant and wear-resistant materials, such as stainless steel, special plastics, or ceramics, to ensure its long-term stable operation in wastewater environments.

[0031] An external pulsed water source refers to an external water supply system capable of providing pulsed water flows with specific pressure, flow rate, and time intervals. This source typically includes one or more high-pressure pumps, an energy storage device (such as an accumulator), and a control valve system. The high-pressure pump is responsible for pressurizing the water to the required operating pressure, while the accumulator stores energy and releases it for a short period to generate instantaneous high-pressure pulses. The control valve system controls the opening, closing, and duration of the pulsed water flow according to a preset cleaning program, thereby achieving periodic, high-intensity rinsing of the light source shield 3.

[0032] Based on the existing pulse backwash port 10, a nozzle connected to the pulse backwash port 10 and facing the reaction chamber 4 was introduced, and an external pulse water source was connected. When the external pulse water source is activated, the high-pressure water flow is accelerated and focused through the nozzle, forming a jet with high flow velocity and strong impact force. This jet can act on the outer circumferential surface of the light source shield 3, and combined with the unsteady impact effect provided by the external pulse water source, it forms a high-velocity kinetic energy jet pointing towards the surface of the light source shield 3. The high-energy pulse water flow can generate instantaneous physical impact force and shear peeling force, effectively destroying and removing high-viscosity, high-adhesion organic dirt adhering to the surface of the light source shield 3, including stubborn deposits in the dead corners of the micro-grooves 7 or protrusions 8, improving the cleaning effect of the light source shield 3, ensuring the light transmittance of the light source 2 and the continuous and efficient photocatalytic reaction, thereby reducing the equipment maintenance cost and downtime, and ensuring the stability and efficiency of the system in treating recalcitrant organic wastewater.

[0033] The pulse backwash port 10 is located at the end of the reaction chamber 4 near the outlet 6. During photocatalytic oxidation, especially when treating high-viscosity, high-adhesion organic wastewater, reaction products or incompletely degraded pollutants tend to deposit and adhere more easily in the area where the fluid leaves the reaction chamber 4, i.e., near the outlet 6. The placement of the pulse backwash port 10 in this embodiment allows the backwash water flow to better target key areas where dirt easily accumulates. Specifically, the pulse backwash port 10 can be integrated into the end cap of the reaction chamber 4 or connected to the wall of the reaction chamber 4 via a separate pipeline. The orientation and angle of its nozzle can be optimized according to the geometry and hydrodynamic characteristics of the reaction chamber 4 to ensure that the jet water flow effectively covers and impacts the area near the outlet 6 on the outer circumference of the light source shield 3.

[0034] The grooves 7 and ridges 8 are alternately distributed, and adjacent ridges 8 and the grooves 7 between them together form a swirling guide groove. On the outer circumference of the light source cover 3, the grooves 7 and ridges 8 are arranged in a regular and continuous interval along the spiral path, providing a continuous guiding path for the fluid. The regular alternating distribution structure can be formed on the surface of the light source cover 3 by precision molding or CNC machining to ensure its geometric accuracy and consistency.

[0035] When the fluid flows on the surface of the light source shield 3, it is not guided by a single groove 7 or ridge 8, but by a fluid channel formed by the space defined by a ridge 8 and the grooves 7 on both sides, or a groove 7 and the ridges 8 on both sides. The geometric parameters of the swirling guide groove, such as depth, width and helix angle, can be optimized according to the actual treatment requirements to achieve control of the wastewater flow.

[0036] The swirling guide channel ensures clear and continuous geometric boundaries for the fluid channels on the outer circumference of the light source shield 3. This allows wastewater to be more effectively guided after entering the reaction chamber 4, forming a stable and uniform swirling flow. This reduces localized stagnation or short-circuiting of the fluid on the shield surface. Because the fluid is forced to move along a pre-defined spiral path, the shearing action between the fluid and the shield surface is enhanced, helping to disrupt the laminar boundary layer and promoting mass transfer efficiency from pollutants to the catalyst surface. Simultaneously, the uniform swirling distribution allows the wastewater to be more fully exposed to ultraviolet light, improving light energy utilization and thus enhancing the oxidative decomposition efficiency of recalcitrant organic matter.

[0037] A spiral guide vane is provided on the inner wall of the outer shell 1. The spiral guide vane is fixed to the inner wall of the outer shell 1 to guide the direction of fluid movement and optimize the flow field distribution within the reaction chamber 4. The spiral guide vane can be made of various materials, such as stainless steel, polytetrafluoroethylene (PTFE), and other corrosion-resistant materials. Its installation method can be integral molding, welding, or mechanical fixing. The geometric parameters of the guide vane, such as the spiral angle, vane height, vane width, and vane spacing, can be optimized according to the dimensions of the reaction chamber 4, the viscosity of the wastewater to be treated, and the required flow field intensity to ensure that the fluid can be effectively guided.

[0038] The spiral guide vane on the inner wall of the outer shell 1 and the swirling guide groove on the outer circumference of the light source shield 3 are aligned in the direction of fluid rotation. If the swirling guide groove guides the fluid to rotate clockwise, the spiral guide vane is also designed to guide the fluid to rotate clockwise, reducing the shearing or counter-current effects that may occur between the inner and outer walls of the annular reaction chamber 4, so that the fluid forms a uniform and stable spiral flow pattern throughout the entire reaction chamber 4.

[0039] The spiral guide vanes on the outer wall and the swirling guide grooves on the inner light source shield 3 form a fluid channel in the same direction, forcing the fluid in the entire annular cavity to maintain a consistent rotational motion. This reduces the short-circuiting of fluid through areas with low resistance and minimizes the dead zone of flow velocity within the reaction chamber 4, ensuring that the wastewater receives uniform and sufficient illumination throughout the entire reaction chamber 4. Simultaneously, this synergistic guiding mechanism enhances the tangential velocity component of the fluid, thereby strengthening the centrifugal force's pressing effect and shearing scouring effect on the surface of the light source shield 3. This achieves continuous cleaning and efficient mass transfer of the photocatalytic interface throughout the entire reaction process, further improving the treatment efficiency and stability of recalcitrant organic wastewater.

[0040] like Figure 1As shown, the inlet 5 and outlet 6 are connected through a circulation pipe 12 outside the outer casing 1. A heat exchanger 11 is coupled to the circulation pipe 12 to exchange heat with the wastewater inside. A circulation pump 13 is installed on the circulation pipe 12. After being treated in the reaction chamber 4, the wastewater can be guided back to the reaction chamber 4 for further treatment, forming a closed or semi-closed circulation loop. This allows the wastewater to pass through the photocatalytic reaction zone multiple times, effectively extending the contact time between the wastewater and the light source 2, and increasing the accumulation time of organic pollutants by the photocatalyst.

[0041] By adjusting the circulation flow rate, the residence time of wastewater can be flexibly controlled to adapt to the treatment needs of wastewater with different concentrations and degradation difficulties. A heat exchanger 11 coupled to the circulation pipe 12 is used for heat exchange with the wastewater within the circulation pipe 12. The heat exchanger 11 can heat or cool the wastewater as needed, maintaining the wastewater temperature in the reaction chamber 4 within the optimal temperature range for the photocatalytic reaction. For example, cooling can prevent the ultraviolet lamp from overheating and affecting its lifespan and light output efficiency, while heating can increase the reaction rate. The heat exchanger 11 can be a plate heat exchanger 11, a shell-and-tube heat exchanger 11, or a coaxial heat exchanger 11, selected according to the properties of the wastewater, the treatment volume, and the required heat exchange efficiency. A circulating water pump 13 is used to drive the wastewater to flow between the circulation pipe 12 and the reaction chamber 4. By adjusting the operating parameters of the circulating water pump 13, such as the speed or flow rate, the circulation rate of the wastewater and its residence time in the reaction chamber 4 can be controlled, thereby optimizing the conditions for the photocatalytic reaction. The circulating water pump 13 is usually selected from the type of pump that is corrosion-resistant and wear-resistant in order to adapt to the wastewater treatment environment.

[0042] The heat exchanger 11 regulates the wastewater temperature within the reaction chamber 4, ensuring the photocatalytic reaction proceeds within a suitable temperature range. This reduces the risk of performance degradation due to excessively high temperatures or reduced reaction efficiency due to excessively low temperatures, maintaining the optimal photoelectric conversion efficiency of the ultraviolet lamp and preventing overheating, cracking, or spectral drift. The circulating water pump 13 ensures stable wastewater circulation, working in conjunction with the heat exchanger 11 to achieve precise control of the thermodynamic environment of the reaction system. This significantly improves the treatment efficiency and depth of recalcitrant organic wastewater, ensuring the stability and compliance of the final effluent quality. Furthermore, by optimizing reaction conditions, it extends the equipment's lifespan and reduces operating and maintenance costs.

[0043] A temperature sensor is installed inside the reaction chamber 4. The temperature sensor, circulating water pump 13, and heat exchanger 11 are connected to the controller. The temperature sensor measures the temperature of the wastewater in the reaction chamber 4 and sends it to the controller. The controller adjusts the operating status of the circulating water pump 13 and the heat exchanger 11. Forced heat exchange of the circulating fluid through the heat exchanger 11 precisely controls the thermodynamic environment of the reaction system. Combined with the circulating pump, multiple reflux irradiation of the material is achieved. This maintains the ultraviolet lamps operating within the temperature range of optimal photoelectric conversion efficiency, preventing overheating and cracking or spectral drift. Furthermore, by accumulating reaction time, the effective irradiation time is increased, achieving deep treatment of recalcitrant organic compounds such as benzene rings and heterocyclic compounds, ensuring the stability and compliance of the final effluent quality.

[0044] Specifically, a temperature sensor installed inside reaction chamber 4 is used to monitor the temperature of the wastewater within reaction chamber 4 in real time. This temperature sensor can be of the type of resistance temperature detector (RTD), thermocouple, or semiconductor temperature sensor, and its measuring end is typically immersed in the wastewater to ensure accurate acquisition of wastewater temperature data. By continuously or periodically collecting temperature information, it provides the basic data for subsequent temperature control. The controller is the core of the entire temperature control system, responsible for receiving the wastewater temperature data sent by the temperature sensor and calculating the adjustment commands for the circulating water pump 13 and heat exchanger 11 based on the preset temperature target value and control algorithm. The controller can be a programmable logic controller (PLC), microcontroller, or industrial computer, integrating data processing, logic judgment, and output control functions to achieve intelligent management of the system's operating status.

[0045] A circulating water pump 13 drives wastewater to flow between the reaction chamber 4 and the circulation pipe 12. The controller can control the wastewater's circulation flow rate and velocity by adjusting the operating state of the circulating water pump 13, such as changing its speed or start-stop frequency. Changes in flow rate affect the wastewater's residence time in the heat exchanger 11 and the heat exchange efficiency with the heat exchange medium, thus indirectly affecting the wastewater temperature in the reaction chamber 4. The heat exchanger 11 exchanges heat with the wastewater in the circulation pipe 12 to raise or lower its temperature. The controller can directly and precisely adjust the wastewater temperature by adjusting the operating state of the heat exchanger 11, such as controlling the flow rate, temperature, or heating / cooling power of the heat exchange medium. A temperature sensor transmits temperature data in analog or digital signal form to the controller; the controller then sends control commands, such as PWM signals, 4-20mA current signals, or switching signals, to the circulating water pump 13 and the heat exchanger 11 through digital or analog output ports to achieve precise control over them.

[0046] The outer casing 1 has an observation port 14 and an instrument mounting port 15. The light source cover 3 is made of transparent material and isolates the light source 2 from the reaction chamber 4. The observation port 14 is a transparent window set at a specific location on the outer casing 1. Its material can be a material with high light transmittance, corrosion resistance, and a certain mechanical strength, such as quartz glass, tempered glass, or special polymer materials. This observation port 14 allows operators to directly visually inspect the internal operating conditions of the reaction chamber 4, such as the wastewater flow pattern, the working status of the light source 2, and whether there is dirt adhering to the surface of the light source cover 3, thereby facilitating the timely detection and handling of potential problems.

[0047] Instrument mounting port 15 refers to the interface reserved on the housing 1 for installing various sensors. These interfaces are usually designed as standard threaded or flanged interfaces to facilitate the connection of monitoring instruments such as temperature sensors, pH sensors, ultraviolet light intensity sensors, and pressure sensors. Through these instruments, various key operating parameters within the reaction chamber 4 can be obtained in real time and accurately, providing data support for the optimized control and fault diagnosis of the system.

[0048] The light source shield 3 is made of a transparent material, meaning that the material of the shield has good light transmittance, especially high transmittance for specific wavelengths (such as ultraviolet light) emitted by the light source 2. Commonly used transparent materials include high-purity quartz glass, which has excellent transmittance and chemical stability for ultraviolet light. The light source shield 3 isolates the light source 2 from the reaction chamber 4, and the light source 2 is completely enclosed inside the light source shield 3, preventing direct contact with the wastewater in the reaction chamber 4. The two ends of the light source shield 3 are usually connected to the outer shell 1 or support structure through sealing structures (such as O-rings, flange seals, etc.), forming an independent, dry internal space to protect the light source 2 from wastewater corrosion, contamination, and thermal shock.

[0049] Example 2 In another typical embodiment of the present invention, such as Figures 1-2 As shown, a working method for a photocatalytic oxidation treatment system for recalcitrant organic wastewater is presented. The system, as described in Example 1, includes the following steps: Wastewater enters tangentially through inlet 5 and is guided by the spirally distributed swirling guide grooves 9 on the outer circumference of the light source shield 3, generating a strong swirling flow that matches the inlet angle, breaking the laminar boundary layer on the surface of the light source shield 3, and renewing the fluid that is in close contact with the light source shield 3. The light source 2 emits ultraviolet light, which passes through the shield and enters the reaction chamber 4. The grooves 7 and protrusions 8 on the surface of the shield serve as optical scattering / refractive interfaces, expanding the contact area between the light source 2 and the wastewater, enabling the wastewater in a highly turbulent state to capture more light energy and efficiently oxidize and decompose organic matter. The pulse backwash port 10 outputs a pulsed water flow, which uses instantaneous impact force to directly disturb the outer circumference of the light source cover 3, peeling off the dirt deposited on the groove 7 and the protrusion 8, and restoring the light transmittance.

[0050] Measure the temperature of the wastewater injected into the reaction chamber 4, and adjust the wastewater flow rate at the inlet 5 and outlet 6.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the 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 system for photocatalytic oxidation treatment of biorefractory organic wastewater, characterized by, The application relates to a light catalytic oxidation treatment system for difficult biodegradable organic wastewater, which comprises an outer shell and a light source. The outer circumferential surface of the light source cover is provided with spiral grooves and convex edges, which form a spiral flow guide groove on the outer circumferential surface of the light source cover, and the spiral angle of the spiral flow guide groove matches the cutting angle of the water inlet.

2. The photo-catalytic oxidation treatment system for biorefractory organic wastewater according to claim 1, wherein The pulse backwash port is connected with a nozzle towards the reaction chamber.

3. The photo-catalytic oxidation treatment system for biorefractory organic wastewater according to claim 2, wherein The pulse backwash port is arranged at one end of the reaction chamber close to the water outlet.

4. The photo-catalytic oxidation treatment system for biorefractory organic wastewater according to claim 1, wherein The grooves and convex edges are alternately distributed in sequence, and adjacent convex edges and the grooves therebetween jointly form a spiral flow guide groove.

5. The photo-catalytic oxidation treatment system for biorefractory organic wastewater according to claim 4, wherein The outer wall of the outer shell is provided with a spiral flow guide piece, and the spiral direction of the spiral flow guide piece is the same as that of the spiral flow guide groove.

6. The photo-catalytic oxidation treatment system for biorefractory organic wastewater according to claim 1, wherein The water inlet and the water outlet are communicated through a circulating pipe outside the outer shell, the circulating pipe is coupled with a heat exchanger to exchange heat with the wastewater in the circulating pipe, and a circulating water pump is installed on the circulating pipe.

7. The photo-catalytic oxidation treatment system for biorefractory organic wastewater according to claim 7, wherein A temperature sensor is installed in the reaction chamber, and the temperature sensor, the circulating water pump and the heat exchanger are respectively connected to a controller.

8. The photo-catalytic oxidation treatment system for biorefractory organic wastewater according to claim 1, wherein The outer shell is provided with an observation port and an instrument installation port, the light source cover is made of transparent material, and the light source is isolated from the reaction chamber.

9. A method of operating a photocatalytic oxidation treatment system for the treatment of biorefractory organic wastewater, characterized by, The application relates to a light catalytic oxidation treatment system for difficult biodegradable organic wastewater, which comprises an outer shell and a light source. Wastewater enters tangentially through the water inlet and is guided by the spiral flow guide groove spirally distributed on the outer circumferential surface of the light source cover, strong spiral flow matching the water inlet angle is generated, the laminar boundary layer on the surface of the light source cover is destroyed, and the fluid close to the light source cover is updated; The light source emits ultraviolet light, which penetrates the cover and enters the reaction chamber, the grooves and convex edges on the surface of the cover serve as optical scattering / refraction interfaces, the contact area of the light source with the wastewater is expanded, the wastewater in a high turbulent state can capture more light energy, and organic matters are efficiently oxidized and decomposed; The pulse backwash port outputs pulse water flow, uses instantaneous impact force to directly disturb the outer circumferential surface of the light source cover, peels off dirt deposited on the grooves and convex edges, and restores light transmittance.

10. The working method of the photo-catalytic oxidation treatment system for the biorecalcitrant organic wastewater as claimed in claim 9, characterized in that, The temperature of the injected wastewater in the reaction chamber is measured, and the wastewater flow of the water inlet and the water outlet is adjusted.

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