Thin tube flow type reaction evaluation device and method for wastewater ozone-ultraviolet process optimization

Abstract

The invention discloses a thin tube flow type reaction evaluation device and method for wastewater ozone (O3)-ultraviolet (UV) process optimization. The invention provides a slim tube flow type O3-UV reaction system (MFOUS), the core device of the system is a slim tube flow photoreactor composed of a quartz tube, a polytetrafluoroethylene hollow fiber membrane and a shading tube, the system can accurately measure and conveniently adjust key operation parameters such as the O3 dosage and the UV dosage, the contribution of O3 and hydroxyl free radicals is optimized and balanced, and the operation efficiency of the system is improved. The high-efficiency degradation of refractory organics (ROCs) in sewage is realized, the energy consumption is reduced, and a sewage treatment plant is assisted to realize a carbon neutralization target. Compared with an operation mode of a sequencing batch O3-UV reactor, the method has the advantages of simplicity and convenience in operation, accuracy in UV dosage measurement, low sample requirement and the like, can be used for quickly, simply and conveniently optimizing an O3-UV advanced treatment process aiming at different sewage qualities, and has a wide application prospect.

Description

Technical Field

[0001] The present invention relates to a fine tube flow reaction evaluation device and method for optimizing the ozone-ultraviolet process of wastewater, belonging to the technical field of environmental protection water treatment. Background Art

[0002] The rapid development of modern industry has promoted the large-scale production of synthetic chemicals, and at the same time, a large amount of wastewater containing refractory organic compounds (ROCs) has been generated. If not properly treated, these secondary effluents (SEs) from urban sewage will cause serious harm to the ecological environment. As the last barrier for pollutants to enter the environment, sewage treatment plants are the key nodes to block the spread of pollutants. However, the traditional biological treatment process has limited efficiency in removing ROCs and is difficult to meet the increasingly strict emission requirements. Therefore, advanced oxidation processes (AOPs) need to be used for in-depth treatment. According to the water quality characteristics of SEs, AOPs can directly reduce the chemical oxygen demand (COD) of SEs to meet the discharge standards, or enhance the biodegradability of SEs by increasing the ratio of biochemical oxygen demand (BOD) to COD (BOD / COD), creating favorable conditions for the subsequent biological treatment process (such as biofilm process) to further degrade COD.

[0003] The ozone-ultraviolet (O3-UV) combined process is an effective method for removing ROCs in water. This process combines a chemical oxidation process (COP, i.e., O3 molecule oxidation) and an advanced oxidation process (AOP, i.e., hydroxyl radical (HO · ) oxidation). Its ideal design is to degrade most of the ROCs through O3 and then further degrade the remaining O3-resistant ROCs through HO · . However, although this process is theoretically efficient, its high energy consumption problem limits its wide application. Currently, there is still a lack of research on the optimization of the key parameters of the O3-UV process, especially on how to balance the contributions of COP and AOP to minimize energy consumption. One of the reasons for this problem may be the lack of experimental devices that can accurately simulate the O3-UV process, accurately measure and conveniently adjust the key operating parameters. Existing studies mostly use batch reactors, in which UV lamps are placed at the center of the reactor and O3 diffusers are immersed in the solution. Although this reactor structure is simple, its batch operation mode is difficult to simulate the sequential O3-UV process (i.e., O3 first and then O3-UV), and it is also unable to flexibly adjust the key parameters such as O3 dosage (ML) and UV dose (F p ). In addition, the non-uniform distribution of UV irradiation intensity (E p ) in the batch reactor results in difficult accurate measurement of operating parameters, thus making it impossible to accurately evaluate energy consumption and increasing the difficulty of process optimization.

[0004] In recent years, due to its advantages such as high mass transfer efficiency, fast reaction speed, and flexible operation, the capillary flow technology has gradually been applied to the field of wastewater treatment. The capillary flow reactor can significantly improve the contact efficiency between O3 and wastewater through microchannel design, shorten the reaction time, and reduce energy consumption. However, existing capillary flow systems are mostly used for single oxidation process research and have not been combined with the O3-UV process. In addition, existing optimization methods mostly rely on a single parameter (such as ML or F p ), lack of multi-parameter collaborative regulation, and it is difficult to achieve high efficiency and energy conservation.

[0005] To address these problems, developing a capillary flow reaction evaluation device for optimizing the O3-UV process of wastewater that can accurately measure and conveniently adjust key operating parameters, achieve process optimization, and minimize energy consumption is of great significance for wastewater treatment plants to achieve the carbon neutrality goal. Summary of the Invention

[0006] The object of the present invention is to provide a capillary flow reaction evaluation device and method for optimizing the O3-UV process of wastewater, which can optimize the O3-UV process, reduce energy consumption, and achieve efficient degradation of ROCs in wastewater by accurately measuring and conveniently adjusting key operating parameters (ML and F p ).

[0007] The capillary flow reaction evaluation device for optimizing the O3-UV process of wastewater provided by the present invention includes a photoreactor, a UV unit, and an O3 unit;

[0008] The photoreactor includes a plurality of quartz tubes connected in series. The inside of the quartz tube is provided with a PTFE hollow fiber membrane, and the outside is wrapped with a light-shielding tube; the inside of the PTFE hollow fiber membrane serves as the O3 gas flow channel, and the cavity between the PTFE hollow fiber membrane and the quartz tube serves as the flow channel for the solution to be measured. The flow directions of the O3 gas and the solution to be measured are opposite;

[0009] The quartz tube is provided with a sampling port, preferably located at the end of the quartz tube, for real-time sampling during the reaction process;

[0010] The light-shielding tube can be made of aluminum foil (light-shielding rate > 99.9%) to block UV irradiation. Changing the position of the light-shielding tube can change the UV exposure length (l exp , cm) of the quartz tube, thereby changing the UV exposure time (t UV ) of the solution to be measured.

[0011] The UV unit includes a UV lamp and a fluorescence microprobe. The UV lamp is arranged along the central axis of the photoreactor, and the fluorescence microprobe is installed outside the UV lamp for real-time monitoring of E p ;

[0012] The O3 unit is used to generate O3 and quench the O3 tail gas.

[0013] In the capillary flow reaction evaluation device of the present invention, the quartz tubes are radially distributed equidistantly around the UV lamp, and the radial distance is 5-15 cm to ensure that each quartz tube obtains the same E. p Same.

[0014] In the capillary flow reaction evaluation device of the present invention, the length of the quartz tube can be 30-50 cm, and the inner diameter can be 0.4-1.0 cm;

[0015] The outer diameter of the PTFE hollow fiber membrane can be 0.2-0.45 cm;

[0016] The fluorescence microprobe is installed about 1 cm from the UV lamp for real-time monitoring of the fluctuation of E. p Fluctuation;

[0017] The above parameters can be adjusted according to specific circumstances and are not limited to the above range.

[0018] In the capillary flow reaction evaluation device of the present invention, the O3 unit includes an oxygen tank, an O3 reactor, an O3 concentration detector, an O3-resistant tube, and an O3 tail gas absorption bottle. The O3 reactor and the O3 tail gas absorption bottle are connected to the PTFE hollow fiber membrane through the O3-resistant tube; O3 concentration detectors are provided at both the O3 inlet and outlet of the PTFE hollow fiber membrane for real-time detection of the O3 gas concentration at the inlet and outlet of the photoreactor to judge the consumption of O3 gas;

[0019] The O3 tail gas absorption bottle contains 20% potassium iodide (KI) solution for absorbing the unreacted O3 gas.

[0020] In the capillary flow reaction evaluation device of the present invention, the capillary flow reaction evaluation device further includes a sampling unit, which includes a water inlet tank and a water inlet pump connected in sequence. The outlet of the water inlet pump is connected to the water inlet provided on the quartz tube.

[0021] The device of the present invention can achieve accurate determination and convenient adjustment of key parameters (ML and F). p )

[0022] Through the capillary flow reaction evaluation device of the present invention, the key operating parameters (ML and F) of MFOUS can be calibrated. Subsequently, based on MFOUS, the reduction effect of chemical oxygen demand (COD) or the improvement effect of biodegradability (BOD / COD) of different SEs in the O3-UV process can be quickly evaluated. p )

[0023] Based on the above-mentioned capillary flow reaction evaluation device, the present invention further provides an energy consumption evaluation method for the O3-UV process. Combining this method, according to the wastewater treatment target, the O3-UV process is optimized to reduce energy consumption, which specifically includes the following steps:

[0024] S1. Pre-run the UV lamp and O3 generator until E p and the O3 concentration are stable;

[0025] Since the power of the O3 generator and the flow rate of the solution to be measured (Q w ) will affect ML and F p , they need to be preset according to the required experimental conditions;

[0026] S2. Pump the solution to be measured into the cavity between the quartz tube and the PTFE hollow fiber membrane, and the O3 gas flows reversely through the inner cavity of the PTFE hollow fiber membrane, so that the O3 molecules penetrate through the membrane micropores and dissolve into the solution to be measured;

[0027] Through the reverse flow of the solution to be measured and the O3 gas, the gaseous O3 molecules can continuously penetrate through the micropores of the membrane and dissolve into the working solution without forming any bubbles;

[0028] S3. Take samples at the sampling port, and measure the chemical oxygen demand COD and biochemical oxygen demand BOD concentrations of the samples to evaluate the COD removal or BOD / COD enhancement effects in the solution to be measured under different O3 dosages ML and UV doses F p conditions.

[0029] The method further includes adjusting the covering length of the light-shielding tube to change t UV , measuring the chemical oxygen demand COD and biochemical oxygen demand BOD concentrations, and further exploring the influence of F p ;

[0030] When all the quartz tubes are completely covered by the shielding tube (i.e., UV irradiation is completely shielded), the degradation of ROCs in the single O3 process can be measured according to different ML values. Then, adjust the position of the shielding tube (i.e., adjust t UV ), and the influence of F p can be explored.

[0031] The key operating parameters for the present invention to degrade ROCs in the solution to be measured include the solution residence time (t), ML, and F p . The t for the working solution to flow through each sampling port can be obtained according to the following formula:

[0032]

[0033] where, V urepresents the volume difference between each quartz tube and the hollow fiber membrane, with the unit of mL; n represents the number of quartz tubes; Q w is the flow rate of the solution to be measured, with the unit of mL s -1 .

[0034] The present invention adopts the membrane aeration technology. Compared with the traditional use of O3 aeration heads, a significantly higher O3 diffusion rate (α, s -1 ) can be obtained. ML (kg m -3 ) is defined as the amount of O3 introduced into the solution to be measured. When the power of the O3 generator and Q w are fixed, the ML value at a specific sampling port can be calculated by Equation 2:

[0035] ML = α × 1000 × ([O3] g,in - [O3] g,out ) × t (2)

[0036] A shielding tube is installed outside the quartz tube to block UV irradiation. Changing the position of the shielding tube can change the l exp of the quartz tube, thereby changing the t UV of the solution to be measured. Therefore, t UV (s) and F p (einstein m -2 ) can be calculated as follows:

[0037]

[0038] where r1 and r2 are the inner radius of the quartz tube and the outer radius of the PTFE hollow fiber membrane, respectively, with the unit of cm; ε 254 represents the molar absorption coefficient of uridine, with the value of 8742 M -1 cm -1 ; φ u represents the quantum yield of uridine photolysis, with the value of 0.02 moleinstein -1 .

[0039] The present invention significantly improves the contact efficiency between O3 and wastewater and shortens the reaction time through the design of a capillary flow reactor (combination of a quartz tube and a PTFE hollow fiber membrane). Compared with the traditional sequential batch reactor, the microchannel structure enhances the gas-liquid mass transfer rate and reduces the O3 diffusion resistance, thereby improving the degradation efficiency of ROCs.

[0040] The present invention can monitor and independently adjust ML and F p in real time. By balancing the contributions of COP and AOP, overconsumption of a single process can be avoided. For example, for SEs with different water quality characteristics, a synergistic strategy of O3 first and then UV or an adjustment of ML-F pThe combination can reduce energy consumption by 20%-30% under the same treatment effect (such as the optimization case of SE-2 in Example 3).

[0041] In the present invention, the position of the light-shielding tube is adjustable, and by changing the UV exposure length (l exp ), the dynamic control of the UV action time is realized to meet the requirements of different reaction stages. Multiple sampling ports support real-time collection of samples with different residence times, quickly evaluate the COD removal rate or the improvement effect of BOD / COD, and complete the multi-parameter combination analysis in a single experiment, greatly shortening the process optimization cycle.

[0042] In the present invention, E p is monitored in real time by a fluorescence microprobe (MFSD) to avoid measurement errors caused by uneven UV intensity distribution in traditional reactors. The O3 concentration detector has a dual-port (inlet / outlet) design to accurately calculate the O3 consumption. Combined with the membrane aeration technology, it ensures that the calibration error of the ML value is ≤5%.

[0043] The thin-tube flow design of the present invention greatly reduces the sample volume required for a single experiment (only 10%-20% of that of traditional reactors), reduces the reagent and wastewater treatment costs. At the same time, the PTFE hollow fiber membrane has strong corrosion resistance, extends the service life of the device, and reduces the maintenance frequency.

[0044] Through the structural design (linkage of quartz tube - PTFE membrane - light-shielding tube) and precise parameter regulation technology, the present invention solves the bottleneck problems in the existing O3-UV process, such as low mass transfer efficiency, high energy consumption, and difficulty in quantifying operation parameters, providing an efficient, energy-saving, and customizable evaluation and optimization tool for advanced wastewater treatment, and having significant industrial application value. Brief Description of the Drawings

[0045] Figure 1 It is a schematic diagram of the thin-tube flow reaction evaluation device provided by the present invention for optimizing the O3-UV process of wastewater;

[0046] The marks in the figure are as follows:

[0047] 1 water inlet tank, 2 water inlet pump, 3 water inlet, 4 oxygen tank, 5 O3 generator, 6 O3 concentration detector, 7 O3-resistant tube, 8 O3 tail gas absorption bottle, 9 photoreactor, 10 UV lamp, 11 fluorescence microprobe, 12 light-shielding tube, 13 quartz tube, 14 PTFE hollow fiber membrane, 15 water outlet.

[0048] Figure 2 For the O3 dosage (ML) kinetics (a) at different [O3] g-in values and the degradation kinetics (b) of uridine under UV irradiation, experimental conditions: Qw = 0.083 mL s -1 and T = 25 ± 1°C.

[0049] Figure 3 For the changes of COD degradation (Figure a) and BOD / COD improvement (Figure b) during the O3-UV process with ML and t UV Experimental conditions: [O3] g-in = 29.6 mg L -1 , Q w = 0.083 mL s -1 and T = 25 ± 1 °C. Specific implementation manner

[0050] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods.

[0051] Unless otherwise specified, the materials, reagents, etc. used in the following examples can all be obtained from commercial channels.

[0052] Example 1. Fine-tube flow reaction evaluation device for optimizing the O3-UV process of wastewater

[0053] As Figure 1 shown, it is a structural schematic diagram of the fine-tube flow reaction evaluation device for optimizing the O3-UV process of wastewater provided by the present invention, including a photoreactor, a UV unit, an O3 unit, a sampling unit, and a sampling unit.

[0054] As Figure 1 shown, in the photoreactor 9, each quartz tube 13 is connected in series, with a PTFE hollow fiber membrane 14 placed inside and a light-shielding tube 12 wrapped outside. The cavity between the inner wall of the series-connected quartz tubes 13 and the outer wall of the PTFE hollow fiber membrane 14 is the flow channel for the solution to be measured, and the inside of the PTFE hollow fiber membrane 14 is the O3 gas transmission flow channel. The photoreactor 9 is fixed on a plastic disc bracket and surrounds the UV lamp 10, and the radial distance is 5.0 cm for each quartz tube 13 to ensure that the obtained E p value is the same. The light-shielding tube 12 is required to be telescopable arbitrarily, with a light-shielding rate > 99.9%.

[0055] As Figure 1 shown, in the UV unit, the UV lamp 10 is placed along the central axis of the photoreactor 9, and the fluorescence microprobe 11 is installed about 1 cm away from the UV lamp 10 for real-time monitoring of the fluctuation of E p . The O3 generator 5 is connected in series to the O3 concentration detector 6 and the air inlet of the photoreactor 9 with an O3-resistant tube 7, and then the O3 gas enters the flow channel inside the PTFE hollow fiber membrane 14 in the photoreactor 9. The reacted O3 tail gas is connected in series to the O3 concentration detector 6 and the O3 tail gas absorption bottle 8 from the air outlet of the photoreactor 9 with an O3-resistant tube 7.

[0056] As Figure 1As shown, the oxygen tank 4 supplies oxygen to the O3 generator 5. The O3 concentration detector 6 is used to detect the O3 gas concentration at the inlet and outlet of the photochemical reaction unit 8 in real time to judge the consumption of O3 gas. The O3 tail gas absorption bottle 8 can select 20% potassium iodide (KI) solution to absorb the unreacted O3 gas completely. The oxygen tank 4, the O3 reactor 5, the O3 concentration detector 6, the O3-resistant tube 7 and the O3 tail gas absorption bottle 8 constitute the O3 unit.

[0057] As Figure 1 shown, the sampling unit includes a water inlet tank 1, a water inlet pump 2 and a water inlet 3. The water sample to be measured in the water inlet tank 1 is pumped into the photochemical reactor 9 through the water inlet 3 by the water inlet pump 2 and passes through the sampling ports in sequence. The sampling unit includes a plurality of sampling ports 15. In the present invention, the number of sampling ports is set to 7, which are respectively located at the ends of 7 quartz tubes 13 and are used to collect samples during the reaction process in real time (the number of sampling ports can be adjusted according to actual needs).

[0058] The device provided by the present invention can quickly evaluate the effect of the O3-UV process for advanced treatment of sewage, and has the advantages of simple structure, convenient operation and real-time monitoring.

[0059] Example 2: Method for evaluating the fine tube flow reaction for optimizing the O3-UV process of wastewater

[0060] Using the device provided in Example 1, the evaluation of the fine tube flow reaction for optimizing the O3-UV process of wastewater is realized.

[0061] Before each experiment, the UV lamp and the O3 generator are pre-run for 10 min, which are confirmed by the readings of the MFSD and the O3 monitor respectively to achieve stable working conditions. Since the power of the O3 generator and the solution Q to be measured w will affect ML and F p , it is necessary to make presets according to the required experimental conditions.

[0062] The solution to be measured is continuously pumped into the cavity between the inner side of the quartz tube and the outer side of the hollow fiber membrane by a peristaltic pump ( Figure 1 shown), and the O3 gas flows through the inner space of the hollow fiber membrane in the direction opposite to that of the working solution. By this method, gaseous O3 molecules can continuously penetrate through the micropores of the membrane and dissolve into the solution to be measured without forming any bubbles. The O3 gas concentrations at the inlet ([O3] g,in ) and outlet ([O3] g,out ) of the photochemical reactor are detected by two O3 concentration detectors respectively, and the O3 concentration data are recorded. The O3 tail gas is absorbed by 20% potassium iodide (KI) solution. When the solution to be measured flows through the reactor, samples are taken at specific sampling ports.

[0063] First, at a specific Q wUnder certain conditions, the t values at different sampling ports were measured. Secondly, with the UV lamp turned off and the O3 generator turned on, [O3] was adjusted g,in , and after the O3 concentration was stabilized, an excessive amount of KI (0.2 M) solution was pumped into the quartz tube, and samples were collected from different sampling ports (i.e., representing different t values), titrated with 0.1 M sodium thiosulfate solution, and the theoretical ML value was calculated. By measuring the variation of ML with t at different O3 inlet concentrations (such as 10, 20, 30, 40 mg L -1 ), the α value could be experimentally calibrated, and then according to Formula 2, the ML value of a specific sampling port was calculated. Thirdly, with only the UV lamp turned on, the uridine solution (0.12 mM) was pumped into the quartz tube completely exposed to UV irradiation, samples were taken from different sampling ports, and the absorbance of the uridine sample at 262 nm was measured to determine the pseudo-first-order rate constant k u (s -1 ), and then the F p value of a specific sampling port was calculated according to Formulas 4 and 5. Finally, after the key operating parameters of MFOUS were calibrated, the solution to be measured was pumped into the photoreactor, samples were taken at specific sampling ports, and the COD and BOD concentrations of the samples were measured to be used for rapidly evaluating the effect of COD removal or BOD / COD enhancement in the solution to be measured under different ML and F p conditions.

[0064] Among them, when all quartz tubes were completely covered with a shielding tube (i.e., completely shielding UV irradiation), the degradation of ROCs in the single O3 process could be evaluated. Then, by adjusting the position of the shielding tube (i.e., adjusting t UV ), the influence of F p could be explored.

[0065] Example 3. Treatment of secondary effluent (SEs) from municipal sewage

[0066] The experiment was carried out according to the method in Example 2, and the experimental conditions and results are as follows:

[0067] (1) Calibrate the ML and F p values of MFOUS. Figure 2 The results in Figure a in [reference] show that under different [O3] g-in conditions, ML increased linearly with t, indicating that O3 gas continuously dissolved into the KI solution through the membrane. By plotting the incremental rate of ML vs. [O3] g,in , a linear curve was obtained, and its slope was α (i.e., 4.3×10 -4 s -1 , Figure 2 the inset in Figure a in [reference]), and experiments proved that the α value was independent of [O3] g,in . In the present invention, it was detected that when [O3] g,in = 29.6 mg L-1 When [O3] g,out the value is in the range of 24.6 - 25.0 mg / L -1 and its average value is 24.9 mg / L -1 , substituting into formula 2, the ML value in this experiment can be calculated to be in the range of 0 - 0.435 kg / m -3 . From Figure 2 Figure b in u , it can be seen that the ultraviolet photolysis process of uridine conforms to pseudo-first-order kinetics, and the slope (k -2 ) is 1.23×10 -1 s p , and the calculated E -4 value is 3.05×10 -2 einstein / m -1 s p , and the F -2 value is in the range of 0 - 0.064 einstein / m -2 .

[0068] (2) The present invention selects SEs (SE-1, SE-2, SE-3) from three industrial parks in Hebei, Zhejiang and Shandong for O3-UV advanced treatment experiments. The biodegradability of all three SEs is relatively low (BOD / COD = 0.01 - 0.13), and there are significant differences in the reactivity towards O3. Among them, SE-1 has the highest reactivity and SE-3 has the lowest. The specific water quality characteristics are shown in Table 1.

[0069] During the experiment, when the solution to be measured flows through the reactor, samples are taken through specific sampling ports to measure the COD and BOD concentrations to evaluate the COD removal or BOD / COD enhancement effects under different ML and F p conditions. The results show that the COD of all SEs gradually decreases with the increase of ML (or t). The removal rates of SE-1, SE-2 and SE-3 are 39.3%, 29.8% and 11.4% respectively. There are significant differences in the reactivity of the three SEs towards O3. SE-1 has the highest reactivity and SE-3 has the lowest.

[0070] When UV is introduced during the O3 process, when t UV increases from 0 (the quartz tube is completely shielded) to 210 s (the quartz tube is completely exposed to UV), the COD removal rate of SE-1 only increases by 11.8%, SE-2 increases by 18.0%, while the removal rate of SE-3 increases the most (29.1%) ( Figure 3 Figure a in Figure 3 ). In addition, UV significantly improves the biodegradability of all SEs ( Figure 3 b), t UVWhen increasing from 0 to 210 s, the BOD / COD ratios of SE-1, SE-2, and SE-3 increased by 0.26, 0.42, and 0.57 respectively. The O3-UV process significantly improved the biodegradability of SEs, especially SE-3, by promoting the generation of HO·.

[0071] In practical applications, increasing ML and F p can improve COD removal or enhance BOD / COD, but it will increase energy consumption. For SE-1, delaying the introduction of UV can reduce the unnecessary consumption of HO · by the water matrix; for SE-3, introducing UV earlier can reduce O3 consumption to a certain extent. Therefore, the O3-UV process strategy can be determined according to the water quality characteristics of SE. For SE-1 with slightly exceeded initial COD, the O3-UV (or only O3) process can directly meet the discharge limit (such as COD ≤ 30 mg L -1 ); for SE-2 and SE-3 with significantly exceeded initial COD, the O3-UV process can improve biodegradability (BOD / COD ≥ 0.3).

[0072] Further research found that various ML-F p combinations can achieve similar treatment effects. For example, when the ML-F p combinations are (0.435 kg m -3 and 0.064 einstein m -2 ), (0.373 kg m -3 and 0.046 einstein m -2 ), and (0.311 kg m -3 and 0.046 einstein m -2 ), the COD removal rates of SE-2 are almost the same (47.8 - 47.9%), indicating that optimizing the O3-UV process has the potential to save energy.

[0073] Based on the above analysis, the MFOUS provided by the present invention has the advantages of low sample requirements, short operation time, accurate dosimetry, etc. It can balance the contributions of COP (single O3 oxidation) and AOP (O3-UV) to ROC degradation by accurately adjusting key parameters, and achieve the treatment goal while reducing energy consumption.

[0074] Table 1 Water quality indicators of secondary effluent from urban sewage treatment plants with different sources

[0075] Index SE-1 SE-2 SE-3 <![CDATA[IW a : DW b > 40％：60％ 75％：25％ 50％：50％ Biological process Membrane bioreactor <![CDATA[A2O]]> Biological aerated filter <![CDATA[COD (mg L –1 )]]> 51 94 79 <![CDATA[BOD (mg L –1 )]]> 6.7 6.1 1.1 BOD / COD 0.13 0.06 0.01 <![CDATA[UV 254 (cm –1 )]]> 0.771 1.345 2.425 pH 7.2 7.2 7.4

[0076] a Industrial wastewater. b Domestic sewage.

Claims

1. A fine-tube flow reaction evaluation device for optimizing the ozone-UV process of wastewater, comprising a photoreactor, a UV unit, and an O3 unit; The photoreactor includes a plurality of quartz tubes connected in series. A PTFE hollow fiber membrane is provided inside the quartz tube, and a light-shielding tube is wrapped outside. The inside of the PTFE hollow fiber membrane serves as the O3 gas flow channel, and the cavity between the PTFE hollow fiber membrane and the quartz tube serves as the flow channel for the solution to be measured. The flow directions of the O3 gas and the solution to be measured are opposite; A sampling port is provided on the quartz tube; The UV unit includes a UV lamp and a fluorescence microprobe. The UV lamp is arranged along the central axis of the photoreactor, and the fluorescence microprobe is installed outside the UV lamp for real-time monitoring of the UV irradiation intensity (E p ). The O3 unit is used to generate O3 and quench the O3 tail gas.

2. The capillary tube flow type reaction evaluation device according to claim 1, wherein: The quartz tubes are radially distributed at equal distances around the UV lamp.

3. The capillary tube flow type reaction evaluation device according to claim 1 or 2, characterized in that: The O3 unit includes an oxygen tank, an O3 reactor, an O3 concentration detector, an O3-resistant tube, and an O3 tail gas absorption bottle. The O3 reactor and the O3 tail gas absorption bottle are communicated with the PTFE hollow fiber membrane through the O3-resistant tube. O3 concentration detectors are provided at both the O3 inlet and the outlet of the PTFE hollow fiber membrane.

4. The capillary tube flow type reaction evaluation device according to any one of claims 1-3, wherein: The fine-tube flow reaction evaluation device further includes a sample injection unit, which includes a water inlet tank and a water inlet pump connected in sequence. The outlet of the water inlet pump is connected to the water inlet provided on the quartz tube.

5. A method for optimizing and evaluating the O3-UV process of wastewater by using the device according to any one of claims 1-4, comprising the following steps: S1. Pre-run the UV lamp and O3 generator until the concentrations of E p and O3 are stable; S2. Pump the solution to be measured into the cavity between the quartz tube and the PTFE hollow fiber membrane, and the O3 gas flows reversely through the inner cavity of the PTFE hollow fiber membrane, so that O3 molecules dissolve into the solution to be measured through the membrane micropores; S3. Sample at the sampling port and measure the chemical oxygen demand (COD) and biochemical oxygen demand (BOD) concentrations of the sample to evaluate the COD removal or BOD / COD enhancement effect in the solution to be measured under different O3 dosage ML and UV dose F. p ​ 6. The method according to claim 5, wherein: The method further includes adjusting the covering length of the light-shielding tube to change the UV exposure time, measuring the chemical oxygen demand (COD) and biochemical oxygen demand (BOD) concentrations, and further exploring the influence of F p on it.

7. The method according to claim 5 or 6, characterized in that: The O3 dosage ML is obtained by the following formula: ML = α × 1000 × ([O3] g,in - [O3] g,out ) × t Among them, [O3] g,in and [O3] g,out respectively represent the O3 gas concentrations at the inlet and outlet of the photoreactor, with the unit of mg / mL -1 ; F p = E p × t UV where r1 and r2 are the inner radius of the quartz tube and the outer radius of the PTFE hollow fiber membrane respectively, with the unit of cm; ε 254 represents the molar absorption coefficient of uridine, with a value of 8742 M -1 cm -1 ; φ u represents the quantum yield of uridine photolysis, with a value of 0.02 moleinstein -1 .

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