Dynamic control method of electrochemical oxidation treatment device for high-salt and high-concentration organic wastewater

Abstract

The present invention discloses a dynamic regulation method for an electrochemical oxidation treatment device for high-salt and high-concentration organic wastewater. The device includes an electrochemical reactor, an absorbance sensor, and an automatic control system; the method specifically comprises: Step (1) recording the absorbances A(292,0), A(385,0), and A(460,0) at three wavelengths at the initial time of the reaction by the absorbance sensor; Step (2) the sensor monitors and records the absorbance at the reaction time t i ; Step (3) the automatic control system controls the pulse width duty ratio of the electrode group of the electrochemical reactor and the pulse width duty ratio of the corrosion-resistant magnetic pump of the electrochemical reactor according to the change of A(385) or A(460); Step (4) the automatic control system controls the on / off of the ultraviolet lamp group of the electrochemical reactor according to the change of A(292). The present invention monitors the absorbance in real time through the absorbance sensor, and accurately converts the monitored absorbance into the control quantities of the electrode group and the magnetic pump through a formula, while achieving efficient removal of organic pollutants, low generation of toxic by-products, and low energy consumption.

Description

Technical Field

[0001] The invention belongs to the field of wastewater treatment, and specifically relates to a dynamic control method of an electrochemical oxidation treatment device for high-salt and high-concentration organic wastewater. Background Art

[0002] my country is the world's largest producer of paints, dyes, antibiotics, and pesticides, which produces a large amount of high-salt and high-concentration organic wastewater. High-salt and high-concentration organic wastewater has water quality characteristics such as high salt content, high organic matter concentration, strong toxicity, complex composition, and low biodegradability. Once it enters the natural water environment, it will cause serious ecological safety problems. Therefore, a series of physical, chemical, biological, and advanced oxidation technologies are used at home and abroad to treat this type of wastewater.

[0003] Electrochemical oxidation technology is an advanced oxidation technology with the advantages of no reagent addition, no secondary pollution, small equipment footprint, and easy automation. With the development of the power industry and the reduction of electricity costs, the application prospects and market value of this technology are also constantly improving. Chinese patent application No. 201811542682.3, application date December 17, 2018, discloses a method for treating high-salt and high-concentration organic wastewater by electrocatalytic oxidation-biochemical coupling. This patent achieves efficient treatment of high-salt and high-concentration organic wastewater by organically coupling electrocatalytic oxidation with biochemical treatment technology.

[0004] The effect of electrochemical oxidation is closely related to the current density. The electron transfer rate and hydroxyl radical (·OH) generation rate at low current density are slow, which often requires a long reaction time and may lead to unsatisfactory treatment effects. High current density will transfer more electrons in a short time and produce more ·OH. Therefore, for high-salt and high-concentration organic wastewater, a higher current density is usually used for electrochemical oxidation. For example, Chinese Patent Application No. 201811536099.1, filed on December 14, 2018, discloses a comprehensive treatment method for high-salt and high-concentration organic wastewater. The current density used in the electrochemical oxidation part described in the patent is as high as 500-1000A / m 2 However, at high current density, the concentration of organic matter continues to decrease, the amount of ·OH that reacts with organic matter decreases, and the excess ·OH reacts with the high concentration of Cl in the wastewater. - reaction, producing a large amount of carcinogenic toxic byproducts (ClO2 - 、ClO3 - and ClO4 - etc.)(Jasper et al., 2017), which harms ecological security and increases unnecessary energy consumption.

[0005] In summary, the main problem with the current electrochemical oxidation treatment device method for high-salt and high-concentration organic wastewater is that it is difficult to dynamically optimize and balance the relationship between the removal of organic pollutants and the formation of toxic by-products and energy consumption in real time, that is, it is difficult to simultaneously achieve efficient removal of organic pollutants, low generation of toxic by-products and low energy consumption. Summary of the invention

[0006] In view of the problem that the current electrochemical oxidation treatment device for high-salt and high-concentration organic wastewater is difficult to dynamically optimize and balance the relationship between organic pollutant removal and toxic by-product formation and energy consumption in real time, the present invention aims to provide a dynamic optimization and control method for the electrochemical oxidation treatment device for high-salt and high-concentration organic wastewater, which realizes efficient removal of organic pollutants, low generation of toxic by-products and low energy consumption at the same time by using an absorbance sensor to monitor the absorbance during the reaction process in real time and continuously adjusting the current size according to the absorbance.

[0007] The technical solution to achieve the purpose of the present invention is: a dynamic control method of an electrochemical oxidation treatment device for high-salt and high-concentration organic wastewater, the device comprising an electrochemical reactor, an absorbance sensor and an automatic control system; the method specifically comprises the following steps:

[0008] Step (1): Record the absorbance of the absorbance sensor at the initial three wavelengths, A(292,0), A(385,0) and A(460,0);

[0009] Step (2): During the reaction process, the sensor monitors and records the reaction time t in real time i The absorbance data at t is recorded as A(292,t i )、A(385,t i ) and A(460,t i );

[0010] Step (3): The automatic control system controls the pulse width duty cycle PWM of the electrode group of the electrochemical reactor according to the change of A (385) or A (460) I Pulse width duty cycle PWM of corrosion resistant magnetic pump for electrochemical reactor V ;

[0011] Step (4): The automatic control system controls the switch of the ultraviolet lamp group of the electrochemical reactor according to the change of A (292).

[0012] Furthermore, step (3) specifically includes the following steps:

[0013] The pulse width duty ratio PWM of the electrode group at the beginning of the reaction I 100% corrosion resistant magnetic pump pulse width duty cycle PWM V is 0;

[0014] If the initial absorbance A(385,0)≤1.5cm -1 , the change of A(385) is used as the feedback control signal of the electrode group driving current and the circulation flow rate of the corrosion-resistant magnetic pump. i The electrode group pulse width duty ratio PWM I =100%×(A(385,t i )-0.1×A(385,0)) / (0.9×A(385,0)), pulse width duty cycle PWM of corrosion-resistant magnetic pump V =100%×(A(385,t i )-A(385,0)) / (0.9×A(385,0)), that is, when A(385,t i )≤(0.1×A(385,t i =0)), the pulse width duty ratio PWM of the electrode group I =0 and stops working, while the pulse width duty cycle of the corrosion-resistant magnetic pump is 100%, and it stops working after delaying working for 0.1 to 1h at rated power;

[0015] If the initial absorbance A(385,0)>1.5cm -1 And A(460,0)≤1.5cm -1 , A(460) is selected as the feedback control signal of the electrode group driving current and the circulation flow rate of the corrosion-resistant magnetic pump. i The electrode group pulse width duty ratio PWM I =100%×(A(460,t i )-0.1×A(460,0)) / (0.9×A(460,0)), pulse width duty cycle PWM of corrosion-resistant magnetic pump V =100%×(A(460,t i )-A(460,0)) / (0.9×A(460,0)), that is, when A(460,t i )≤(0.1×A(460,0)), the pulse width duty ratio PWM of the electrode group I =0 and stops working, while the pulse width duty cycle of the corrosion-resistant magnetic pump is 100%, and it stops working after delaying working for 0.1 to 1h at rated power;

[0016] If the initial absorbance A(460,0)>1.5cm -1 , pre-treat the raw water first, and then select the treatment method based on A(385,0) and A(460,0) after pre-treatment.

[0017] Furthermore, the step (4) is specifically as follows:

[0018] When A(292,t i )≤1.0cm -1 When the current measurement data A(292,t i ) and the previous measured data A(292,t i-1 ), if ΔA(292) data is positive, that is, A(292,t i ) value starts to increase gradually, the UV lamp group turns on, and continues to work for 0.1 to 1 hour after the electrode group stops working, and then stops working.

[0019] Furthermore, the absorbance sensor uses 292±5nm ultraviolet LED, 385±5nm ultraviolet LED and 460±5nm blue light LED as light sources, and works in pulse stroboscopic mode in turn during measurement. Two gallium nitride-based photodiodes and one silicon-based photodiode are used to detect the ultraviolet light intensity and the blue light intensity, respectively, so as to measure the absorbance of three wavelengths of A(292), A(385) and A(460), respectively.

[0020] Furthermore, the ultraviolet lamp group adopts an ultraviolet LED array light source with a central wavelength of 292±5nm.

[0021] Furthermore, the ultraviolet lamp group adopts a low-pressure mercury lamp ultraviolet light source with a central wavelength of 254nm.

[0022] Furthermore, the electrochemical reactor also includes a reactor tank, a water inlet pipe, a drain pipe and a circulation pipeline;

[0023] The circulation pipeline connects the water inlet and outlet of the electrochemical reactor, and the internal circulation of the liquid is realized by a corrosion-resistant magnetic pump; the electrode group is an anode and a cathode arranged alternately and the circuit is set in parallel; two oppositely arranged ultraviolet lamp groups are distributed on both sides of each electrode group, and the electrode group and the ultraviolet lamp group are evenly distributed in the reactor tank; the electrochemical reactor adopts a sequencing batch reaction mode, including three stages of water inlet, reaction and drainage, and the absorbance sensor is placed inside the electrochemical reactor; the automatic control system is connected to the absorbance sensor to monitor and obtain absorbance data of three wavelengths in real time; the automatic control system supplies power to the electrode group and the ultraviolet lamp group respectively in a constant current drive mode, and adjusts the driving current size by pulse width modulation; the automatic control system is connected to the corrosion-resistant magnetic pump, and adjusts the circulation flow rate by pulse width modulation.

[0024] Furthermore, the anode of the electrode group adopts one or more of boron-doped diamond film, ruthenium-iridium-titanium, tin-antimony-titanium, iridium-tantalum-titanium, and graphite electrode.

[0025] Compared with the prior art, the present invention has the following significant advantages:

[0026] (1) The dynamic control method of the present invention uses an absorbance sensor to monitor the absorbance data A (385) and A (460) in real time during the reaction process, and the automatic control system continuously adjusts the driving current pulse width duty cycle PWM of the electrode group according to the changes of A (385) or A (460) I and pulse width duty cycle PWM of corrosion-resistant magnetic pump V , so that the driving current is always lower than the limiting current required to oxidize the organic matter concentration, and the circulation flow rate is increased to enhance mass transfer when the organic matter concentration is low, thereby achieving efficient removal of organic pollutants, low generation of toxic by-products and low energy consumption.

[0027] (2) The dynamic control method of the present invention quantifies the relationship between the absorbance change and the driving current pulse width duty cycle of the electrode group and the pulse width duty cycle of the corrosion-resistant magnetic pump through a formula, thereby achieving dynamic and precise regulation of the oxidation process and improving the control accuracy.

[0028] (3) The dynamic control method of the present invention monitors the absorbance data A (292) in the reaction process in real time through an absorbance sensor. The automatic control system then turns on the ultraviolet light when the chlorine evolution side reaction begins to occur according to the change of A (292), thereby decomposing HClO / ClO - Produce Cl· and ·OH to oxidize organic matter; on the other hand, inhibit the subsequent ClO2 - 、ClO3 - and ClO4 - The formation of toxic by-products. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a front view of the processing device of the present invention.

[0030] Figure 2 It is a top view of the processing device of the present invention.

[0031] Figure 3 It is a schematic diagram of the structure of the electrode group in the processing device of the present invention.

[0032] Figure 4 It is a schematic diagram of the structure of the ultraviolet lamp group in the processing device of the present invention.

[0033] Figure 5 The figure is a schematic flow chart of the dynamic control method of the present invention.

[0034] Description of reference numerals:

[0035] 1-reactor body, 2-electrode group, 3-ultraviolet lamp group, 4-corrosion-resistant magnetic pump, 5-water inlet pipeline, 6-drainage pipeline, 7-circulation pipeline, 8-absorbance sensor, 201-anode, 202-cathode, 203-insulating gasket, 204-fixing rod, 301-low-pressure mercury lamp, 302-LED lamp, 303-quartz glass sleeve. DETAILED DESCRIPTION

[0036] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0037] Example 1

[0038] For electrochemical oxidation processes under mass transfer control, the maximum oxidation rate of organic matter can be defined by the concept of limiting current, which is only related to the organic matter concentration and fluid dynamics conditions. When the driving current exceeds the limiting current, part of the current will be wasted in oxygen and chlorine evolution reactions, resulting in unnecessary energy consumption and the production of ClO2 - 、ClO3 - and ClO4 - Toxic byproducts such as oxidative stress are produced. In order to achieve a balance between the removal of organic pollutants and the formation of toxic byproducts and energy consumption, the driving current needs to be adjusted in multiple steps so that it does not exceed the limiting current. A (385) and A (460) can be adjusted according to the organic concentration. Therefore, the driving current can be continuously adjusted according to the changes in A (385) or A (460) to ensure that the driving current is always lower than the limiting current required for the oxidation of organic concentration, and the circulation flow rate is continuously adjusted to improve mass transfer, thereby achieving efficient removal of organic pollutants, low generation of toxic byproducts and low energy consumption. In addition, the chlorine evolution reaction produces a large amount of HClO / ClO - , which has an obvious absorption peak at 292nm. Therefore, according to the change of A(292), when the chlorine evolution side reaction begins, ultraviolet light can be turned on to decompose HClO / ClO - Produce Cl· and ·OH to oxidize organic matter; on the other hand, inhibit the subsequent ClO2 - 、ClO3 - and ClO4 - The formation of toxic by-products.

[0039] This embodiment provides an electrochemical oxidation treatment device for high-salt and high-concentration organic wastewater, including an electrochemical reactor, an absorbance sensor, and an automatic control system. Figure 1As shown, the electrochemical reactor includes a reactor tank 1, an electrode group 2, an ultraviolet lamp group 3, a corrosion-resistant magnetic pump 4, a water inlet pipe 5, a drain pipe 6 and a circulation pipeline 7, and an absorbance sensor 8 is placed inside the electrochemical reactor. The electrochemical reactor adopts a sequential batch reaction method, including three stages: water inlet, reaction and drainage. The automatic control system is connected to the absorbance sensor 8 to monitor and obtain absorbance data of three wavelengths (A (292), A (385) and A (460)) in real time; the automatic control system supplies power to the electrode group 2 and the ultraviolet lamp group 3 respectively in a constant current drive mode, and the driving current can be adjusted; the automatic control system is also connected to the corrosion-resistant magnetic pump 4 to adjust the circulation flow rate by pulse width modulation. As shown Figure 2 As shown, the electrode group mainly includes an anode 201, a cathode 202, an insulating gasket 203 and a fixing rod 204. The anode uses 7 pieces 201 of boron-doped diamond film, and the cathode uses 6 pieces 202 of stainless steel electrodes. The anode 201 and the cathode 202 are arranged alternately and the circuit is set in parallel. The distance between the cathode and the cathode is controlled by the insulating gasket 203, and the anode and the cathode are fixed by two fixing rods 204. Two UV lamp groups 3 arranged opposite to each other are distributed on both sides of each electrode group 2. Figure 3 As shown, the UV lamp assembly is mainly composed of a low-pressure mercury lamp 301 with a central wavelength of 254nm and a quartz glass sleeve 302. The quartz glass sleeve wraps the low-pressure mercury lamp to achieve a waterproof effect. The circulation pipeline 7 connects the water inlet and outlet of the electrochemical reactor, and the internal circulation of the liquid is realized through the corrosion-resistant magnetic pump 4.

[0040] The dynamic optimization control method of this embodiment is as follows Figure 4 As shown, after the electrochemical reactor is filled with water, the absorbance data A(292,0), A(385,0) and A(460,0) at the beginning of the reaction are recorded. During the reaction, the sensor monitors and records the reaction time t in real time. i The absorbance data at t is recorded as A(292,t i )、A(385,t i ) and A(460,t i ); the automatic control system controls the pulse width duty ratio PWM of the electrode group according to the change of A (385) or A (460) I and pulse width duty cycle PWM of corrosion-resistant magnetic pump V , the pulse width duty ratio PWM of the electrode group at the initial reaction I 100% (i.e. based on the rated maximum current I max =20A operation), pulse width duty ratio PWM of corrosion-resistant magnetic pump V In this embodiment, the influent is pesticide wastewater from a certain place (a typical high-salt and high-concentration organic wastewater), and the initial absorbance A(385,0)≤1.5cm -1, the change of A(385) is selected as the feedback control signal of the electrode group driving current and the circulation flow rate of the corrosion-resistant magnetic pump. i The electrode group pulse width duty ratio PWM I =100%×(A(385,t i )-0.1×A(385,0)) / (0.9×A(385,0)), while the pulse width duty cycle PWM of the corrosion-resistant magnetic pump V =100%×(A(385,t i )-A(385,0)) / (0.9×A(385,0)), that is, when A(385,t i )≤(0.1×A(385,t i =0)), the pulse width duty ratio PWM of the electrode group I =0 and stops working, while the pulse width duty cycle of the corrosion-resistant magnetic pump is 100%, and it stops working after 0.5h of delay at rated power. The automatic control system controls the switch of the ultraviolet lamp group according to the change of A(292). During the processing, when A(292,t i )≤1.0cm -1 When the current measurement data A(292,t i ) and the previous measured data A(292,t i-1 ), if ΔA(292) data is positive, that is, A(292,t i ) value begins to increase gradually, the UV lamp group is turned on, and continues to work for a period of 0.5h after the electrode group stops working, and then stops working. When the electrode group, UV lamp group and magnetic pump all stop working, the reactor starts to drain.

[0041] The pesticide wastewater treatment scale in this embodiment is 2t / d, which was run for 1 week, with a reaction time of 8-12h. The inlet and outlet water were sampled once a day and analyzed and tested. The treatment effect is shown in Table 1.

[0042] Table 1 Wastewater treatment effect in this embodiment

[0043] 1 2 3 4 5 6 7 COD removal (%) 88.7 89.2 85.7 88.3 90.4 91.5 89.7 <![CDATA[ClO2 - Production amount (mg / L)]]> 2.5 4.4 3.9 2.8 3.3 4.6 5.4 <![CDATA[ClO3 - Production amount (mg / L)]]> 14.2 16.5 17.1 15.6 16.2 17.3 15.8 <![CDATA[ClO4 - Production amount (mg / L)]]> 6.3 7.2 6.8 6.5 7.7 7.6 7.8 <![CDATA[Energy consumption (kWh / m 3 )]]> 17.6 14.2 18.9 16.9 16.2 18.2 15.4

[0044] COD removal rate is 85.7~91.5%, ClO2 - 、ClO3 - and ClO4 - The generation amount is less than 6, 18 and 8 mg / L respectively, and the energy consumption is 14.2-18.9 kWh / m 3 .

[0045] Example 2

[0046] The difference between the electrochemical oxidation treatment device for high-salt and high-concentration organic wastewater provided in this embodiment and in Embodiment 1 is that an ultraviolet LED with a central wavelength of 290±5 nm is used as the light source of the ultraviolet lamp group 3 .

[0047] The dynamic optimization control method of this embodiment is as follows Figure 4 As shown, after the electrochemical reactor is filled with water, the absorbance data A(292,0), A(385,0) and A(460,0) at the beginning of the reaction are recorded. During the reaction, the sensor monitors and records the reaction time t in real time. i The absorbance data at t is recorded as A(292,t i )、A(385,t i ) and A(460,t i ); the automatic control system controls the pulse width duty ratio PWM of the electrode group according to the change of A (385) or A (460) I and pulse width duty cycle PWM of corrosion-resistant magnetic pump V , the pulse width duty ratio PWM of the electrode group at the initial reaction I 100% (i.e. based on the rated maximum current I max =20A operation), pulse width duty ratio PWM of corrosion-resistant magnetic pump V In this embodiment, the influent is a printing and dyeing wastewater (a typical high-salt and high-concentration organic wastewater), and the initial absorbance A(385,0)>1.5cm -1 And A(460,0)≤1.5cm -1 , the change of A(460) is selected as the feedback control signal of the electrode group driving current and the circulation flow rate of the corrosion-resistant magnetic pump. i The electrode group pulse width duty ratio PWM I =100%×(A(460,t i )-0.1×A(460,0)) / (0.9×A(460,0)), while the pulse width duty cycle PWM of the corrosion-resistant magnetic pump V =100%×(A(460,t i )-A(460,0)) / (0.9×A(460,0)), that is, when A(460,t i )≤(0.1×A(460,t i =0)), the pulse width duty ratio PWM of the electrode group I =0 and stops working, while the pulse width duty cycle of the corrosion-resistant magnetic pump is 100%, and it stops working after 0.5h of delay at rated power. The automatic control system controls the switch of the ultraviolet lamp group according to the change of A(292). During the processing, when A(292,t i )≤1.0cm -1When the current measurement data A(292,t i ) and the previous measured data A(292,t i-1 ), if ΔA(292) data is positive, that is, A(292,t i ) value begins to increase gradually, the UV lamp group is turned on, and continues to work for a period of 0.5h after the electrode group stops working, and then stops working. When the electrode group, UV lamp group and magnetic pump all stop working, the reactor starts to drain.

[0048] This embodiment is a printing and dyeing wastewater treatment scale of 3t / d, which was run for 1 week, with a reaction time of 10-15h. The inlet and outlet water were sampled once a day and analyzed and tested. The treatment effect is shown in Table 2.

[0049] Table 2 Wastewater treatment effect in this embodiment

[0050] 1 2 3 4 5 6 7 COD removal (%) 83.9 82.4 85.1 84.2 86.4 87.3 86.1 <![CDATA[ClO2 - Production amount (mg / L)]]> 3.7 4.2 3.9 4.5 5.3 5.6 4.8 <![CDATA[ClO3 - Production amount (mg / L)]]> 14.2 15.6 14.2 13.6 15.5 15.2 14.7 <![CDATA[ClO4 - Production amount (mg / L)]]> 6.7 5.6 4.8 5.2 4.5 4.2 6.3 <![CDATA[Energy consumption (kWh / m 3 )]]> 17.9 18.2 16.3 18.2 17.8 16.5 19.8

[0051] COD removal rate is 82.4~87.3%, ClO2 - 、ClO3 - and ClO4 - The generation amount is less than 5, 16 and 7 mg / L respectively, and the energy consumption is 16.3-19.8 kWh / m 3 .

[0052] Example 3

[0053] The difference between this embodiment and embodiment 1 is that a ruthenium-iridium-titanium electrode is used as the anode, and other implementation conditions remain unchanged.

[0054] The scale of pesticide wastewater treatment in this embodiment is 2t / d, which was run for 1 week, with a reaction time of 14-18h. The inlet and outlet water were sampled once a day and analyzed and tested. The treatment effect is shown in Table 3.

[0055] Table 3 Wastewater treatment effect in this example

[0056] 1 2 3 4 5 6 7 COD removal (%) 55.8 50.7 58.5 61.3 62.5 60.4 57.2 <![CDATA[ClO2 - Production amount (mg / L)]]> 4.5 3.5 2.5 3.4 4.2 3.5 2.8 <![CDATA[ClO3 - Production amount (mg / L)]]> 12.4 13.6 12.6 11.4 13.2 13.8 13.2 <![CDATA[ClO4 - Production amount (mg / L)]]> 4.3 3.4 4.4 4.5 3.5 3.2 4.5 <![CDATA[Energy consumption (kWh / m 3 )]]> 25.8 23.2 24.7 25.2 26.7 22.6 25.1

[0057] COD removal rate is 50.7~62.5%, ClO2 - 、ClO3 - and ClO4 - The generation amount is less than 5, 14 and 5 mg / L respectively, and the energy consumption is 22.6-26.7 kWh / m 3 .

[0058] Comparative Example 1

[0059] The high-salt and high-concentration organic wastewater electrochemical oxidation treatment device provided in this comparative example is consistent with Example 1.

[0060] This comparative example does not use the above-mentioned dynamic optimization control method. That is, the automatic control system in the above-mentioned device is not used, and the pulse width duty ratio PWM of the electrode group is I Always 100% (i.e. at the rated maximum current I max =20A operation), pulse width duty ratio PWM of corrosion-resistant magnetic pump V The UV lamp is kept off and the direct reaction is terminated after 12 hours.

[0061] This comparative example is a pesticide wastewater treatment scale of 2t / d, which was run for 1 week with a reaction time of 12h. The inlet and outlet water were sampled once a day and analyzed and tested. The treatment effect is shown in Table 11.

[0062] Table 11 Wastewater treatment effect in this example

[0063] 1 2 3 4 5 6 7 COD removal (%) 85.8 88.3 89.3 87.4 88.3 84.3 89.4 <![CDATA[Effluent ClO2 - Concentration (mg / L)]]> 11.4 11.2 10.4 11.7 9.5 10.6 9.8 <![CDATA[Effluent ClO3 - Concentration (g / L)]]> 3.5 3.4 3.4 3.3 3.6 3.8 3.5 <![CDATA[Effluent ClO4 - Concentration (g / L)]]> 11.4 10.3 12.1 12.4 12.4 12.8 12.3 <![CDATA[Energy consumption (kWh / m 3 )]]> 68.4 58.6 67.3 72.4 74.9 65.2 69.3

[0064] COD removal rate is 84.3~89.4%, ClO2 - The production is less than 12 mg / L, but ClO3 - The amount of ClO4 generated is as high as 3.3-3.8 g / L - The generation volume is as high as 10.3-12.8g / L, and the energy consumption is as high as 58.6-74.9kWh / m 3 .

[0065] Compared with Example 1, the COD removal rate in this comparative example is close to that in Example 1, but a large amount of toxic byproduct ClO3 is generated. - and ClO4 - , and the energy consumption is greatly increased, so the effluent toxicity and operating cost are significantly higher than those in Example 1.

Claims

1. A dynamic control method for an electrochemical oxidation treatment device for high-salt and high-concentration organic wastewater, characterized in that: The device includes an electrochemical reactor, an absorbance sensor and an automatic control system; the method specifically includes the following steps: Step (1): Record the absorbance of the absorbance sensor at the initial three wavelengths, A(292,0), A(385,0) and A(460,0); Step (2): During the reaction process, the sensor monitors and records the reaction time t in real time i The absorbance data at t is recorded as A(292,t i ) 、 A(385,t i ) and A(460,t i ); Step (3): The automatic control system controls the pulse width duty cycle PWM of the electrode group of the electrochemical reactor according to the change of A (385) or A (460) I Pulse width duty cycle PWM of corrosion resistant magnetic pump for electrochemical reactor V ; Step (4): the automatic control system controls the switch of the ultraviolet lamp group of the electrochemical reactor according to the change of A (292); Step (3) specifically includes the following steps: The pulse width duty ratio PWM of the electrode group at the beginning of the reaction I 100% corrosion resistant magnetic pump pulse width duty cycle PWM V is 0; If the initial absorbance A(385,0)≤1.5cm -1 , the change of A(385) is used as the feedback control signal of the electrode group driving current and the circulation flow rate of the corrosion-resistant magnetic pump. i The electrode group pulse width duty ratio PWM I =100%×(A(385,t i )-0.1×A(385,0)) / (0.9×A(385,0)), pulse width duty cycle PWM of corrosion-resistant magnetic pump V =100%×(A(385,t i )-A(385,0)) / (0.9×A(385,0)), that is, when A(385,t i )≤(0.1×A(385,t i =0)), the pulse width duty ratio PWM of the electrode group I =0 and stops working, while the pulse width duty cycle of the corrosion-resistant magnetic pump is 100%, and it stops working after delaying working for 0.1 to 1h at rated power; If the initial absorbance A(385,0)>1.5cm -1 And A(460,0)≤1.5cm -1 , A(460) is selected as the feedback control signal of the electrode group driving current and the circulation flow rate of the corrosion-resistant magnetic pump. i The electrode group pulse width duty ratio PWM I =100%×(A(460,t i )-0.1×A(460,0)) / (0.9×A(460,0)), pulse width duty cycle PWM of corrosion-resistant magnetic pump V =100%×(A(460,t i )-A(460,0)) / (0.9×A(460,0)), that is, when A(460,t i )≤(0.1×A(460,0)), the pulse width duty ratio PWM of the electrode group I =0 and stops working, while the pulse width duty cycle of the corrosion-resistant magnetic pump is 100%, and it stops working after delaying working for 0.1 to 1h at rated power; If the initial absorbance A(460,0)>1.5cm -1 , pre-treat the raw water first, and then select the treatment method according to A(385,0) and A(460,0) after pre-treatment; The step (4) is specifically as follows: when A(292,t i )≤1.0cm -1 When the current measurement data A(292,t i ) and the previous measured data A(292,t i-1 ), if ΔA(292) data is positive, that is, A(292,t i ) When the value starts to increase gradually, the UV lamp group turns on, and continues to work for 0.1 to 1 hour after the electrode group stops working, and then stops working; The electrochemical reactor also includes a reactor tank, a water inlet pipe, a drain pipe and a circulation pipeline; The circulation pipeline connects the water inlet and outlet of the electrochemical reactor, and the internal circulation of the liquid is realized by a corrosion-resistant magnetic pump; the electrode group is an anode and a cathode arranged alternately and the circuit is set in parallel; two UV lamp groups arranged opposite to each other are distributed on both sides of each electrode group, and the electrode group and the UV lamp group are evenly distributed in the reactor tank; the electrochemical reactor adopts a sequencing batch reaction mode, including three stages of water inlet, reaction and drainage, and the absorbance sensor is placed inside the electrochemical reactor; the automatic control system is connected to the absorbance sensor to monitor and obtain absorbance data of three wavelengths in real time; the automatic control system supplies power to the electrode group and the UV lamp group respectively in a constant current drive mode, and adjusts the driving current size by pulse width modulation; The automatic control system is connected to the corrosion-resistant magnetic pump and the circulation flow rate is adjusted by pulse width modulation.

2. The dynamic control method according to claim 1, characterized in that: The absorbance sensor uses 292±5nm ultraviolet LED, 385±5nm ultraviolet LED and 460±5nm blue light LED as light sources. During measurement, it works in pulse stroboscopic mode in turn. Two gallium nitride-based photodiodes and one silicon-based photodiode are used to detect the ultraviolet light intensity and blue light intensity respectively, thereby measuring the absorbance of three wavelengths A(292), A(385) and A(460) respectively.

3. The dynamic control method according to claim 2, characterized in that: The ultraviolet lamp group adopts an ultraviolet LED array light source with a central wavelength of 292±5nm.

4. The dynamic control method according to claim 3, characterized in that: The ultraviolet lamp group adopts a low-pressure mercury lamp ultraviolet light source with a central wavelength of 254nm.

5. The dynamic control method according to claim 4, characterized in that: The anode of the electrode group adopts one or more of boron-doped diamond film, ruthenium-iridium-titanium, tin-antimony-titanium, iridium-tantalum-titanium and graphite electrode.

Images