Treatment process of nereistoxin pesticide wastewater

Abstract

The invention relates to the technical field of wastewater treatment, in particular to a nereistoxin pesticide wastewater treatment process which comprises the following steps: sequentially feeding nereistoxin agricultural wastewater into a filter tank, a pH regulating tank, a Fenton oxidation tank, a flocculation tank, an electrocatalytic oxidation tank, a pre-anoxic tank, a CASS tank and a disinfection tank for treatment. Wherein the concentration of hydrogen peroxide is dynamically controlled in the Fenton oxidation pond. The invention aims to avoid the problem that cyanide ions in the nereistoxin pesticide wastewater are not reacted thoroughly and a large amount of harmful gas ammonia is released, improve the capability of removing nereistoxin in agricultural wastewater treatment, and improve the biodegradability of the nereistoxin pesticide wastewater at the same time.

Description

Technical Field

[0001] The present application relates to the technical field of wastewater treatment, and in particular to a process for treating nereistoxin-type pesticide wastewater. Background Art

[0002] Nereidotoxin pesticides are a type of modern synthetic insecticide. The amount of wastewater produced by nereidotoxin pesticides is large, the concentration of pollutants is high, and the toxicity is high. The purpose of treating nereidotoxin pesticide wastewater is to reduce the concentration of pollutants in the wastewater as much as possible and strive to achieve harmlessness.

[0003] As a commonly used advanced oxidation technology, Fenton oxidation can destroy organic matter in the dark and has the advantages of simple operation process, easy reaction, low operating cost and low equipment investment. Fenton oxidation usually puts a fixed amount of hydrogen peroxide into the Fenton oxidation tank to produce Fenton oxidation reaction. However, the water quality and water volume of nereistoxin pesticide wastewater are extremely unstable. It is impossible to sense the Fenton oxidation status of the Fenton oxidation tank in time and dynamically adjust the concentration of hydrogen peroxide in the Fenton oxidation tank. There is a problem that nereistoxin in nereistoxin pesticide wastewater is not completely removed and harmful gas ammonia is released. Summary of the invention

[0004] In view of the above, it is necessary to provide a treatment process for nereis toxin pesticide wastewater to solve the above problems.

[0005] One embodiment of the present application provides a process for treating nereistoxin pesticide wastewater, the process comprising:

[0006] S1: Filter and treat large particles and impurities in nereistoxin-containing agricultural wastewater in a filtration tank;

[0007] S2: The wastewater treated by the filter tank is fed into the pH adjustment tank;

[0008] S3: The wastewater treated in the pH adjustment tank is fed into the Fenton oxidation tank, ferrous sulfate solution and hydrogen peroxide solution are added, and the concentration of hydrogen peroxide in the Fenton oxidation tank is dynamically controlled. The specific process is as follows:

[0009] S301: Divide the Fenton oxidation pool into a preset number of regions and number them, collect thermal imaging images of each region at each time; obtain the carbon dioxide concentration and ammonia concentration of the Fenton oxidation pool at each time;

[0010] S302: Segment the thermal imaging images of the other regions of the Fenton oxidation pool except the first region at each time to obtain a plurality of super pixel blocks; analyze the temperature distribution characteristics of each pixel block in each region, and combine the temperature distribution differences of adjacent regions to obtain the thermal uniformity index of each region at each time; wherein the first region is the region closest to the water inlet of the Fenton oxidation pool;

[0011] S303: Compare the carbon dioxide concentration values ​​of each area in the Fenton oxidation tank with the first area at each time, and combine the thermal uniformity index of each area to obtain the intensity of the oxidation reaction in each area at each time; analyze the trend of the intensity of the oxidation reaction in all areas at each time, and combine the ammonia concentration values ​​of all areas at each time to obtain the oxidant addition index of the Fenton oxidation tank at each time;

[0012] S304: adjusting the amount of oxidant added at each moment according to the difference between the oxidant addition coefficient at each moment and the previous moment;

[0013] S4: The wastewater treated in the Fenton oxidation tank is fed into the flocculation tank, and sodium hydroxide and flocculant are added to form flocculent precipitation;

[0014] S5: The clarified nereistoxin pesticide wastewater in the upper layer of the flocculation tank is sequentially fed into the electrocatalytic oxidation tank, the pre-anoxic tank, the CASS tank, and the disinfection tank for treatment.

[0015] Wherein, the pH value of the pH adjustment tank in S2 is 3-5.

[0016] Among them, the residence time of wastewater in S3 in the Fenton oxidation tank is 60 to 90 minutes.

[0017] The specific process of obtaining the thermal uniformity index of each area at each time is as follows:

[0018] Based on the average temperature of all pixels in each superpixel block, the superpixel blocks in each area at each moment are classified to obtain several superpixel block categories;

[0019] Calculate the mean Euclidean distance between each superpixel block category and the central pixel of all other superpixel block categories as the temperature distribution distance of each superpixel block category;

[0020] According to the temperature distribution differences of all pixels in the thermal images of adjacent areas at each moment, combined with the negative correlation mapping results of the temperature distribution distances of each superpixel block category in each area, the thermal uniformity index of each area at each moment is obtained.

[0021] The intensity of the oxidation reaction in each region at each moment is obtained as follows:

[0022] Obtain the ratio of the carbon dioxide concentration value of each area except the first area of ​​the Fenton oxidation pool to that of the first area at each time; and take the product of the ratio and the thermal uniformity index as the intensity of the oxidation reaction of the remaining areas of the Fenton oxidation pool at each time.

[0023] Wherein, the oxidant dosage index of the Fenton oxidation tank at each time is obtained, including:

[0024] The intensity of the oxidation reaction in all areas of the Fenton oxidation pool except the first area at each time is fitted, and the negative correlation mapping of the slope of the fitted straight line is used as the oxidation reaction attenuation degree of the Fenton oxidation pool at each time;

[0025] The average of the ammonia concentration values ​​of all areas of the Fenton oxidation pool at each time is taken as the ammonia emission value of the Fenton oxidation pool at each time;

[0026] The result of merging the oxidation reaction attenuation degree and the ammonia emission value of the Fenton oxidation pool at all times is used as the oxidant dosage coefficient of the Fenton oxidation pool.

[0027] The adjustment of the dosage of the oxidant at each moment is specifically as follows:

[0028] The oxidant dosage supplement value adjusted at the current moment is recorded as r, and its formula form is: Among them, R is the amount of oxidant added at the current moment, E′ is the oxidant addition coefficient at the previous moment, and E is the oxidant addition coefficient at the current moment.

[0029] The pH value of the flocculation tank is adjusted to 8-9 by adding sodium hydroxide; the flocculant is polyacrylamide or polymer aluminum.

[0030] Among them, the hydraulic retention time in the pre-anoxic tank is 8 to 10 hours, the sludge concentration is 2000 to 6000 mg / L, and the dissolved oxygen is controlled at 0.5 mg / L.

[0031] Among them, the residence time of nereistoxin pesticide wastewater in the main reaction zone of the CASS pool is 8 to 10 hours in the aeration stage, 1 to 1.5 hours in the sedimentation stage, 1 to 1.5 hours in the decanting stage, and 0.5 to 1 hour in the idle stage; the sludge concentration is 4000 to 6000 mg / L.

[0032] This application has at least the following beneficial effects:

[0033] 1. The present application organically combines Fenton oxidation, three-dimensional electrocatalytic oxidation and biochemical treatment. The three-dimensional electrocatalytic oxidation generates intermediates with strong oxidizing ability through anodic oxidation or anodic reaction, or other intermediate reactions occur outside the anodic reaction. With the synergistic effect of the catalyst, these intermediates can effectively oxidize the treated pollutants and ultimately achieve the degradation of the pollutants. This method can efficiently degrade organic matter in pesticide wastewater, reduce water toxicity, and will not produce secondary pollution. Improve the removal rate of organic pollutants in nereis toxin pesticide wastewater and reduce energy consumption.

[0034] 2. This application constructs the intensity of the oxidation reaction according to the temperature distribution of the chemical reaction occurring in the Fenton oxidation tank and the carbon dioxide concentration. The beneficial effect is that both the Fenton reaction and the oxidation reaction in the Fenton oxidation tank are exothermic reactions. The intensity of the oxidation reaction can eliminate the interference of the exothermic Fenton reaction, reflect the intensity of the oxidation reaction of nereistoxin pesticide wastewater, and improve the accuracy of subsequent hydrogen peroxide concentration assessment.

[0035] 3. This application analyzes the attenuation degree of the oxidation reaction and the degree of ammonia emission in the Fenton oxidation tank, timely perceives the Fenton oxidation status of the Fenton reaction tank, and dynamically adjusts the concentration of hydrogen peroxide in the Fenton reaction tank by adding oxidants to avoid the problem of incomplete reaction of cyanide ions in nereistoxin pesticide wastewater and release of harmful gas ammonia, thereby improving the removal capacity of nereistoxin in agricultural wastewater and reducing the emission of ammonia in the Fenton oxidation tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A flow chart of a treatment process for nereistoxin pesticide wastewater provided in this application;

[0037] Figure 2 Schematic diagram of the Fenton oxidation pond provided for this application;

[0038] Figure 3 A specific flow chart for controlling the concentration of hydrogen peroxide in a Fenton oxidation tank provided in this application. DETAILED DESCRIPTION

[0039] In the description of the embodiments of the present application, words such as "exemplary", "or", "for example" and the like are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary", "or", "for example" and the like is intended to present related concepts in a concrete manner.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the present application. The terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0041] It should also be noted that the terms "first" and "second" in this application and its drawings are used to distinguish similar objects, rather than to describe a specific order or sequence. The method disclosed in the embodiments of the present application or the method shown in the flow chart includes one or more steps for implementing the method. Without departing from the scope of protection of this application, the execution order of multiple steps can be interchanged with each other, and some steps can also be deleted.

[0042] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0043] Example 1

[0044] Example 1 of the present application proposes a treatment process for nereis toxin pesticide wastewater, which is applied in the field of wastewater treatment technology. Figure 1 , the process comprises:

[0045] S1: The nereistoxin pesticide wastewater is first passed through a filter tank to remove impurities in the wastewater. Specifically, activated carbon is installed in the filter tank to filter out large particles and impurities in the nereistoxin agricultural wastewater to avoid interference of large particles and impurities with subsequent wastewater treatment and improve treatment efficiency.

[0046] S2: The nereistoxin pesticide wastewater treated in the filtration tank is fed into the pH adjustment tank, and a dilute sulfuric acid dosing tank is connected to the pH adjustment tank to adjust the pH value of the wastewater to provide a reaction environment for the subsequent Fenton reaction. The pH adjustment tank adjusts the pH value of the nereistoxin pesticide wastewater to 3.

[0047] S3: The nereisin pesticide wastewater treated by the pH adjustment tank is fed into the Fenton oxidation tank, and an 18% concentration ferrous sulfate solution storage tank is connected to the water inlet of the Fenton oxidation tank, and the dosage of ferrous sulfate solution per ton of wastewater is 6kg. At the same time, a 30% concentration hydrogen peroxide storage tank is connected to 1 / 6 of the Fenton oxidation tank to dynamically control the concentration of hydrogen peroxide in the Fenton oxidation tank. The residence time of the nereisin pesticide wastewater in the Fenton oxidation tank is 60min. The purpose of the Fenton oxidation tank is to oxidize the nereisin in the nereisin pesticide wastewater and pre-oxidize a part of the difficult-to-degrade and highly toxic organic compounds.

[0048] S301: Divide the Fenton oxidation pool into a preset number of areas and number them, collect thermal imaging images of each area at each time; obtain the carbon dioxide concentration and ammonia concentration of the Fenton oxidation pool at each time.

[0049] The present application divides the Fenton oxidation pond into a preset number of regions evenly according to the length from the water inlet to the water outlet, and numbers the regions from small to large according to the distance from the water inlet; it should be noted that in this embodiment, the preset number is 6, and only ferrous sulfate for catalyst action is added to the first region, and hydrogen peroxide has not been added. Hydrogen peroxide has been added to the second to sixth regions, and chemical reactions occur in the regions. The schematic diagram of the Fenton oxidation pond is as follows Figure 2As shown, 201 is the Fenton oxidation pond, 202 is the liquid level of nereis toxin pesticide wastewater, 203 is the addition port of ferrous sulfate solution, 204 is the addition port of hydrogen peroxide solution, 205 is the ferrous sulfate solution storage tank, 206 is the hydrogen peroxide storage tank, and 207 is the third area of ​​the Fenton oxidation pond. An infrared imaging device and a fixed online gas concentration detector are placed just above the center of each area. The infrared imaging device is used to obtain the thermal imaging of the nereis toxin agricultural wastewater in the area. The fixed online gas concentration detector specifically includes an ammonia concentration detector and a carbon dioxide concentration detector to obtain the carbon dioxide concentration data and ammonia concentration data generated in the Fenton oxidation pond. The infrared imaging device, the ammonia concentration detector, and the carbon dioxide concentration detector are synchronously collected, and the collection time interval is 30s and the collection time is 10min. It should be noted that the collection time interval and collection time can be adjusted by the implementer according to the actual situation.

[0050] S302: Segment the thermal imaging images of the Fenton oxidation pool at all times except the first area to obtain a number of super pixel blocks; analyze the temperature distribution characteristics of each pixel block in each area, and combine the temperature distribution differences of adjacent areas to obtain the thermal uniformity index of each area at all times.

[0051] In the Fenton oxidation pool, hydrogen peroxide acts as an oxidant, reacting with the catalyst ferrous sulfate to produce a Fenton reaction, generating highly oxidizing hydroxyl radicals. The main components of nereisin-type agricultural wastewater are sodium cyanide, sodium sulfite, sodium chloride, organic matter and water. The hydroxyl radicals produced by the Fenton reaction can oxidize the cyanide ions in nereisin-type pesticide wastewater, and pre-oxidize a portion of the difficult-to-degrade and highly toxic organic compounds, decomposing them into the final products N2 and CO2 and discharging them.

[0052] The higher the concentration of hydrogen peroxide in the Fenton oxidation pool, the more effective collisions of activated molecules in the nereisin pesticide wastewater will increase, and the nereisin pesticide wastewater at all locations in the Fenton oxidation pool can react, accelerating the oxidation reaction rate and providing an oxidation effect on cyanide and organic matter. At the same time, the chemical reactions in the Fenton oxidation pool are all exothermic reactions, generating a large amount of heat. Therefore, the higher the concentration of hydrogen peroxide, the more intense the chemical reaction in the Fenton oxidation pool, the higher the temperature of the nereisin pesticide wastewater, and the higher the uniformity of the temperature distribution.

[0053] This application takes the thermal imaging image of any area in the 2nd to 6th area of ​​the Fenton oxidation pond at any time as an example, and uses the thermal imaging image as the input of the superpixel segmentation (simple linear iterative cluster, SLIC) algorithm, wherein the number of superpixel blocks in this embodiment is set to 20, and the implementer can set it according to the actual situation, and output each superpixel block of the thermal imaging image, and the temperature of the pixels in each superpixel is similar. The temperature mean of all pixels in each superpixel block in the thermal imaging image is counted, and the temperature mean of all superpixel blocks is used as the input of the natural break algorithm, and the superpixel blocks with different temperature means are divided into K categories. In this embodiment, K is 5, and the superpixel blocks in each category have similar temperatures. The setting of the number of categories can be adjusted by the implementer according to the actual situation. The mean Euclidean distance between each superpixel block category and the central pixel of all other superpixel block categories is calculated as the temperature distribution distance of each superpixel block category.

[0054] According to the temperature distribution difference of all pixels in the thermal imaging images of adjacent regions at each time, combined with the negative correlation mapping result of the temperature distribution distance of each superpixel block category in each region, the thermal uniformity index of each region at each time is obtained; in this embodiment, the temperature distribution difference of the thermal imaging images of the i-th region and the i-1-th region at each time is recorded as A i , where the temperature distribution difference is measured by the difference in the mean temperature; the temperature distribution distance of the kth superpixel block category in the i-th region is recorded as D i,k The negative correlation mapping result is expressed in the form of an inverse, that is, the thermal uniformity index u of the i-th region at each moment i The specific formula is: Where K represents the number of superpixel block categories, i>1.

[0055] It should be understood that the smaller the distance between superpixel block categories, the less local the chemical reaction in the Fenton oxidation pool, and the more active the collision of activated molecules in the nereistoxin pesticide wastewater. At the same time, the greater the temperature difference between adjacent areas, the more intense the chemical reaction in the Fenton oxidation pool, releasing a large amount of heat, and the greater the thermal uniformity index.

[0056] At this point, the thermal uniformity index of any area in the 2nd to 6th areas of the Fenton oxidation tank at any time is obtained to reflect the temperature conditions during the working process of the Fenton oxidation tank.

[0057] S303: Compare the carbon dioxide concentration values ​​of each area in the Fenton oxidation tank with the first area at each moment, and combine the thermal uniformity index of each area to obtain the intensity of the oxidation reaction in each area at each moment; analyze the trend of the intensity of the oxidation reaction of all areas at each moment, and combine the ammonia concentration values ​​of all areas at each moment to obtain the oxidant addition index of the Fenton oxidation tank at each moment.

[0058] There are mainly two types of chemical reactions in the Fenton oxidation pond. One is the Fenton reaction of hydrogen peroxide and ferrous sulfate, which produces strongly oxidizing hydroxyl radicals, which is the basis of the second type of chemical reaction. The other is the oxidation reaction between hydroxyl radicals or hydrogen peroxide and cyanide ions or organic matter in nereistoxin pesticide wastewater. The oxidation reaction mainly includes cyanide destruction reaction and organic matter degradation reaction, which can significantly reduce the cyanide content and organic matter content in nereistoxin pesticide wastewater.

[0059] Both Fenton reaction and oxidation reaction are exothermic reactions. The simple Fenton reaction has a large thermal uniformity index and cannot reflect the intensity of the oxidation reaction of nereis toxin pesticide wastewater in the Fenton oxidation pond. The cyanide breaking reaction and organic matter degradation reaction in the Fenton oxidation pond will release a large amount of carbon dioxide. Based on this, the carbon dioxide concentration values ​​of each area in the Fenton oxidation pond and the first area at each time are compared, and the thermal uniformity index of each area is combined to obtain the intensity of the oxidation reaction of each area at each time: obtain the ratio of the carbon dioxide concentration values ​​of the remaining areas of the Fenton oxidation pond except the first area to the first area at each time; and take the product of the ratio and the thermal uniformity index as the intensity of the oxidation reaction of the remaining areas of the Fenton oxidation pond at each time.

[0060] It should be understood that the larger the thermal uniformity index of each area of ​​the Fenton oxidation pool, the more intense the chemical reaction in the Fenton oxidation pool area, and the more heat is released. The larger the difference in carbon dioxide concentration between each area except the first area and the first area, the larger the chemical reaction in the Fenton oxidation pool area releases a large amount of carbon dioxide, and the more intense the oxidation reaction in the Fenton oxidation pool, that is, the greater the intensity of the oxidation reaction.

[0061] When there is enough hydrogen peroxide in the Fenton oxidation pond, the cyanide ions can be oxidized into harmless nitrogen gas and discharged through the cyanide breaking reaction. When the hydrogen peroxide concentration in the Fenton oxidation pond is low, the hydrogen peroxide concentration is lower in the area with a larger sequence number, resulting in the oxidation reaction gradually attenuating as the sequence number increases.

[0062] Obtain the severity of the oxidation reaction of each area of ​​the Fenton oxidation pool except the first area at each moment, and sort them in order from small to large according to the area number to form an oxidation reaction severity sequence. Obtain the overall trend of the oxidation reaction severity sequence to evaluate the oxidation reaction attenuation of the Fenton oxidation pool at each moment: Specifically, this embodiment uses the least squares method to linearly fit the oxidation reaction severity sequence, the horizontal coordinate of the fitting line is the area number, and the vertical coordinate is the oxidation reaction severity; further, obtain the slope L of the fitting line, and based on the slope, obtain the oxidation reaction attenuation G of the Fenton oxidation pool at each moment; wherein the oxidation reaction attenuation is negatively correlated with the slope, and the specific formula is: G = exp(-L), wherein exp() represents an exponential function with a natural constant as the base.

[0063] It should be understood that the greater the overall change trend of the oxidation reaction intensity sequence, that is, the larger the exp(-L), the greater the Fenton oxidation pool number, the gradually attenuated oxidation reaction in the region, and the greater the attenuation of the oxidation reaction.

[0064] In the Fenton oxidation pond, when the hydrogen peroxide concentration is low and oxidation is insufficient, there are incompletely oxidized ammonium ions in the nereistoxin pesticide wastewater. Due to the heat generated by the chemical reaction in the Fenton oxidation pond and the generation of bubbles, the ammonium ions are easily converted into harmful gas ammonia and escape, producing a foul odor near the Fenton oxidation pond, which is irritating to the human respiratory tract and mucous membranes.

[0065] In this embodiment, the mean of the ammonia concentration values ​​of all areas of the Fenton oxidation pool at each moment is used as the ammonia emission value of the Fenton oxidation pool at each moment; the result of fusing the oxidation reaction attenuation degree of the Fenton oxidation pool at all moments with the ammonia emission value is used as the oxidant addition coefficient of the Fenton oxidation pool: the product of the oxidation attenuation degree and the ammonia emission value at each moment is calculated, and as the result of the fusion, the cumulative sum of the products obtained at the current and previous preset number of moments of the Fenton oxidation pool is calculated, and normalized as the oxidant addition coefficient of the Fenton oxidation pool. In this embodiment, the preset number is 19, and the normalization method adopts the sigmoid function; the implementer can adjust it according to the actual situation.

[0066] It should be understood that the greater the attenuation of the oxidation reaction, the greater the oxidation reaction in the Fenton oxidation tank gradually decays as the serial number increases. At the same time, the higher the ammonia emission value, the more ammonium ions in the nereistoxin pesticide wastewater are converted into ammonia emission. At this time, more oxidant hydrogen peroxide should be added to completely oxidize the cyanide ions and ammonium ions in the nereistoxin pesticide wastewater to produce harmless nitrogen, and the greater the oxidant addition coefficient.

[0067] S304: adjusting the amount of oxidant added at each moment according to the difference between the oxidant addition coefficient at each moment and the previous moment.

[0068] The larger the oxidant addition coefficient is, the more the amount of hydrogen peroxide should be increased to increase the concentration of hydrogen peroxide in the nereis toxin pesticide wastewater. In this embodiment, the oxidant addition supplement value r adjusted at the current moment is obtained by the following formula, and the formula form is: Among them, R is the amount of oxidant added at the current moment, E′ is the oxidant addition coefficient at the previous moment, and E is the oxidant addition coefficient at the current moment. The larger it is, the more likely it is that the Fenton oxidation pond that has been added with oxidant hydrogen peroxide will not be able to support the oxidation reaction and completely oxidize the cyanide ions and ammonium ions in the nereistoxin pesticide wastewater to produce harmless nitrogen gas. The more oxidant hydrogen peroxide should be added to the Fenton oxidation pond, the greater the oxidant addition value.

[0069] An oxidant with a value of r is added to the Fenton oxidation pool to dynamically control the concentration of hydrogen peroxide in the Fenton oxidation pool, thereby increasing the removal rate of nereis toxins in nereis toxin pesticide wastewater and reducing the emission of ammonia in the Fenton oxidation pool.

[0070] Among them, the specific flow chart for controlling the concentration of hydrogen peroxide in the Fenton oxidation tank is as follows: Figure 3 shown.

[0071] S4: The nereistoxin pesticide wastewater treated in the Fenton oxidation tank is fed into the flocculation tank, and the pH value is first adjusted to 8 by adding sodium hydroxide, and then a flocculant is added to the flocculation tank to form a flocculent precipitate, wherein the flocculant can be polyacrylamide.

[0072] S5: The clarified nereis toxin pesticide wastewater in the upper layer of the flocculation tank is pumped into the electrocatalytic oxidation tank through a lifting pump. The electrocatalytic oxidation tank adopts three-dimensional electrocatalytic oxidation technology, which is suitable for the treatment of high COD wastewater. The strong oxidizing substances produced can oxidize and degrade almost all organic matter into short-chain molecules. The electrocatalytic oxidation tank uses a BBD (boron-doped diamond) electrode with titanium as the base material as the anode and a stainless steel plate as the cathode. The initial pH value is 7 and the current density is set to 60mA / cm 2 , the residence time is set to 3h. When the BBD electrode is used as the anode, it can remove the difficult-to-biodegrade organic matter in the nereistoxin pesticide wastewater, improve the biodegradability, and provide a guarantee for subsequent deep treatment.

[0073] The nereitoxin pesticide wastewater treated in the electrocatalytic oxidation tank is fed into the pre-anoxic tank. The pre-anoxic tank provides an anoxic environment to promote the denitrifying bacteria in the sludge to reduce nitrate nitrogen to nitrogen gas, thereby removing nitrogen pollution. The hydraulic retention time is 8h, the sludge concentration is 2000mg / L, and the dissolved oxygen is controlled at 0.5mg / L.

[0074] The nereis toxin pesticide wastewater treated in the pre-anoxic tank is fed into the CASS tank. The CASS tank has a removal effect on pollutants in the nereis toxin pesticide wastewater, and also has good denitrification and phosphorus removal functions. Specifically, the main reaction area of ​​the CASS tank is divided into four stages: aeration, sedimentation, decanting, and idle. The residence time is 8h, 1h, 1h, and 0.5h, respectively. The sludge concentration is 4000mg / L, and the remaining sludge is partially returned to the pre-anoxic tank, and the sludge return ratio is 20%.

[0075] The nereistoxin pesticide wastewater treated in the CASS pool is fed into the disinfection pool, which includes a disinfection area and a clean water area in sequence. The disinfection area can adopt an ultraviolet disinfection pool or a sodium hypochlorite disinfection pool. The nereistoxin pesticide wastewater first passes through the disinfection area with a residence time of 30 minutes, and then flows into the clean water area. The clean water area can be discharged into the receiving water body, thus completing the treatment process of nereistoxin pesticide wastewater.

[0076] Example 2

[0077] Example 2 of the present application proposes a treatment process for nereis toxin pesticide wastewater, which is applied in the field of wastewater treatment technology. Figure 1 , the process comprises:

[0078] S1: The same steps as S1 in Example 1 are used to filter and treat the nereistoxin agricultural wastewater.

[0079] S2: The same steps as S2 in Example 1 are used to adjust the pH of the wastewater after being treated in the filtration tank, wherein the pH adjustment tank adjusts the pH value of the nereistoxin pesticide wastewater to 5.

[0080] S3: The same steps as S3 in Example 1 are adopted to feed the wastewater treated in the pH adjustment tank into the Fenton oxidation tank, wherein the dosage per ton of wastewater is 6 kg of ferrous sulfate solution, and the wastewater stays in the Fenton oxidation tank for 60 min.

[0081] S4: The same steps as S4 in Example 1 are used to feed the wastewater treated in the Fenton oxidation tank into the flocculation tank, wherein sodium hydroxide is added to adjust the pH value to 8, and polymer aluminum is used as the flocculant.

[0082] S5: The clarified nereistoxin pesticide wastewater in the upper layer of the flocculation tank is pumped into the electrocatalytic oxidation tank through a lift pump. The initial pH value is 7 and the current density is set to 80 mA / cm2 , the residence time is set to 3h.

[0083] The nereistoxin pesticide wastewater treated in the electrocatalytic oxidation tank is fed into the pre-anoxic tank, where the hydraulic retention time is 10 hours, the sludge concentration is 4000 mg / L, and the dissolved oxygen is controlled at 0.5 mg / L.

[0084] The nereistoxin pesticide wastewater treated in the pre-anoxic tank is fed into the CASS tank, and the main reaction area of ​​the CASS tank is divided into four stages: aeration, sedimentation, decanting, and idle. The residence times are 8h, 1.5h, 1.5h, and 0.5h, respectively. The sludge concentration is 4000mg / L, and the remaining sludge is partially returned to the pre-anoxic tank, with a sludge return ratio of 25%.

[0085] The nereistoxin pesticide wastewater treated in the CASS pool is fed into the disinfection pool with a retention time of 30 minutes, and then discharged to the clean water area, which can be discharged into the receiving water body, thus completing the treatment process of nereistoxin pesticide wastewater.

[0086] Example 3

[0087] Example 3 of the present application proposes a treatment process for nereis toxin pesticide wastewater, which is applied in the field of wastewater treatment technology. Figure 1 , the process comprises:

[0088] S1: The same steps as S1 in Example 1 are used to filter and treat the nereistoxin agricultural wastewater.

[0089] S2: The pH of the wastewater after being treated in the filter tank is adjusted by the same steps as S2 in Example 1.

[0090] S3: The same steps as S3 in Example 1 are adopted to feed the wastewater treated in the pH adjustment tank into the Fenton oxidation tank, wherein the dosage per ton of wastewater is 8 kg of ferrous sulfate solution, and the residence time of the wastewater in the Fenton oxidation tank is 90 min.

[0091] S4: The same steps as S4 in Example 1 are used to feed the wastewater treated in the Fenton oxidation tank into the flocculation tank, wherein sodium hydroxide is added to adjust the pH value to 9, and polymer aluminum is used as the flocculant.

[0092] S5: The clarified nereistoxin pesticide wastewater in the upper layer of the flocculation tank is pumped into the electrocatalytic oxidation tank through a lift pump. The initial pH value is 9 and the current density is set to 60 mA / cm 2 , the residence time is set to 5h.

[0093] The nereistoxin pesticide wastewater treated in the electrocatalytic oxidation tank is fed into the pre-anoxic tank, where the hydraulic retention time is 10 hours, the sludge concentration is 6000 mg / L, and the dissolved oxygen is controlled at 0.5 mg / L.

[0094] The nereistoxin pesticide wastewater treated in the pre-anoxic tank is fed into the CASS tank, and the main reaction area of ​​the CASS tank is divided into four stages: aeration, sedimentation, decanting, and idle. The residence times are 10h, 1.5h, 1.5h, and 1h, respectively. The sludge concentration is 6000mg / L, and the remaining sludge is partially returned to the pre-anoxic tank, with a sludge return ratio of 40%.

[0095] The nereistoxin pesticide wastewater treated in the CASS pool is fed into the disinfection pool with a retention time of 40 minutes, and then discharged to the clean water area, which can be discharged into the receiving water body, thus completing the treatment process of nereistoxin pesticide wastewater.

[0096] Finally, the treatment results of nereistoxin pesticide wastewater with the hydrogen peroxide concentration in the Fenton oxidation tank controlled (Example) and without the hydrogen peroxide concentration in the Fenton oxidation tank controlled (Comparative Example) were tested, and the statistical results are shown in Table 1:

[0097] Table 1: Test results of examples and comparative examples

[0098]

[0099]

[0100] Among them, the content of nereis toxin is determined by silver nitrate titration; the ammonia concentration is determined by sodium hypochlorite-salicylic acid spectrophotometry, and the ammonia concentration monitoring point is the highest concentration point at the edge of the Fenton oxidation tank, all of which are existing publicly known technologies.

[0101] The flowchart and block diagram in the accompanying drawings show the possible architecture, function and operation of the system, method and computer program product according to the embodiment of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of the code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. In some alternative implementations, the function marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two continuous boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, which can depend on the functions involved. In the description corresponding to the flowchart and the block diagram in the accompanying drawings, the operations or steps corresponding to different boxes can also occur in a different order from the order disclosed in the description, and sometimes there is no specific order between different operations or steps. For example, two continuous operations or steps can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, which can depend on the functions involved. Each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented by a dedicated hardware-based system that performs the specified functions or actions, or may be implemented by a combination of dedicated hardware and computer instructions.

[0102] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A process for treating nereistoxin pesticide wastewater, characterized in that: The process includes: S1: Filter and treat large particles and impurities in nereistoxin-containing agricultural wastewater in a filtration tank; S2: The wastewater treated by the filter tank is fed into the pH adjustment tank; S3: The wastewater treated in the pH adjustment tank is fed into the Fenton oxidation tank, ferrous sulfate solution and hydrogen peroxide solution are added, and the concentration of hydrogen peroxide in the Fenton oxidation tank is dynamically controlled. The specific process is as follows: S301: Divide the Fenton oxidation pool into a preset number of regions and number them, collect thermal imaging images of each region at each time; obtain the carbon dioxide concentration and ammonia concentration of the Fenton oxidation pool at each time; S302: Segment the thermal imaging images of the other regions of the Fenton oxidation pool except the first region at each time to obtain a plurality of super pixel blocks; analyze the temperature distribution characteristics of each pixel block in each region, and combine the temperature distribution differences of adjacent regions to obtain the thermal uniformity index of each region at each time; wherein the first region is the region closest to the water inlet of the Fenton oxidation pool; S303: Compare the carbon dioxide concentration values ​​of each area in the Fenton oxidation tank with the first area at each time, and combine the thermal uniformity index of each area to obtain the intensity of the oxidation reaction in each area at each time; analyze the trend of the intensity of the oxidation reaction in all areas at each time, and combine the ammonia concentration values ​​of all areas at each time to obtain the oxidant addition index of the Fenton oxidation tank at each time; S304: adjusting the amount of oxidant added at each moment according to the difference between the oxidant addition coefficient at each moment and the previous moment; S4: The wastewater treated in the Fenton oxidation tank is fed into the flocculation tank, and sodium hydroxide and flocculant are added to form flocculent precipitation; S5: The clarified nereistoxin pesticide wastewater in the upper layer of the flocculation tank is sequentially fed into the electrocatalytic oxidation tank, the pre-anoxic tank, the CASS tank, and the disinfection tank for treatment.

2. A process for treating nereistoxin pesticide wastewater as claimed in claim 1, characterized in that: The pH value of the pH adjustment tank in S2 is 3-5.

3. A process for treating nereistoxin pesticide wastewater as claimed in claim 1, characterized in that: The residence time of wastewater in S3 in the Fenton oxidation tank is 60 to 90 minutes.

4. A process for treating nereistoxin pesticide wastewater as claimed in claim 1, characterized in that: The specific process of obtaining the thermal uniformity index of each area at each moment is as follows: Based on the average temperature of all pixels in each superpixel block, the superpixel blocks in each area at each moment are classified to obtain several superpixel block categories; Calculate the mean Euclidean distance between each superpixel block category and the central pixel of all other superpixel block categories as the temperature distribution distance of each superpixel block category; According to the temperature distribution differences of all pixels in the thermal images of adjacent areas at each moment, combined with the negative correlation mapping results of the temperature distribution distances of each superpixel block category in each area, the thermal uniformity index of each area at each moment is obtained.

5. A process for treating nereistoxin pesticide wastewater as claimed in claim 1, characterized in that: The intensity of the oxidation reaction in each region at each moment is obtained as follows: Obtain the ratio of the carbon dioxide concentration value of each area except the first area of ​​the Fenton oxidation pool to that of the first area at each time; and take the product of the ratio and the thermal uniformity index as the intensity of the oxidation reaction of the remaining areas of the Fenton oxidation pool at each time.

6. A process for treating nereistoxin pesticide wastewater according to claim 1, characterized in that: The method of obtaining the oxidant dosage index of the Fenton oxidation tank at each time comprises: The intensity of the oxidation reaction in all areas of the Fenton oxidation pool except the first area at each time is fitted, and the negative correlation mapping of the slope of the fitted straight line is used as the oxidation reaction attenuation degree of the Fenton oxidation pool at each time; The average of the ammonia concentration values ​​of all areas of the Fenton oxidation pool at each time is taken as the ammonia emission value of the Fenton oxidation pool at each time; The result of merging the oxidation reaction attenuation degree and the ammonia emission value of the Fenton oxidation pool at all times is used as the oxidant dosage coefficient of the Fenton oxidation pool.

7. The process for treating nereistoxin pesticide wastewater according to claim 1, characterized in that: The adjustment of the amount of oxidant added at each moment is specifically as follows: The oxidant dosage supplement value adjusted at the current moment is recorded as r, and its formula form is: Among them, R is the amount of oxidant added at the current moment, E ′ is the oxidant dosage coefficient at the previous moment, and E is the oxidant dosage coefficient at the current moment.

8. The process for treating nereistoxin pesticide wastewater according to claim 1, characterized in that: The pH value of the flocculation tank is adjusted to 8-9 by adding sodium hydroxide; the flocculant is polyacrylamide or polymer aluminum.

9. A process for treating nereistoxin pesticide wastewater as claimed in claim 1, characterized in that: The hydraulic retention time in the pre-anoxic tank is 8 to 10 hours, the sludge concentration is 2000 to 6000 mg / L, and the dissolved oxygen is controlled at 0.5 mg / L.

10. The process for treating nereistoxin pesticide wastewater according to claim 1, characterized in that: The residence time of nereistoxin pesticide wastewater in the main reaction zone of the CASS pool is 8 to 10 hours in the aeration stage, 1 to 1.5 hours in the sedimentation stage, 1 to 1.5 hours in the decanting stage, and 0.5 to 1 hour in the idle stage; the sludge concentration is 4000 to 6000 mg / L.

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