Method and device for sequencing batch treatment of aniline wastewater

Abstract

The invention discloses a method and a device for sequencing batch treatment of aniline wastewater, and belongs to the technical field of wastewater treatment. The method creatively adopts a physicochemical mode of oil separation, phenolic aldehyde condensation and coagulating sedimentation to treat the high aniline wastewater, firstly, a large amount of heavy oil substances in the wastewater are removed through oil separation treatment, the interference influence on subsequent chemical reactions is reduced, and then the high aniline wastewater is treated by utilizing the principle of amine-aldehyde condensation. According to the invention, formaldehyde and aniline are subjected to condensation covalent cross-linking through aldehyde groups and imino groups to form flocs, and finally, a flocculating agent is added to enhance polymerization bridging between fine flocs to form larger flocs to be discharged, so that a large amount of aniline and derivatives thereof in wastewater can be efficiently removed, and the concentration of organic matters in wastewater is reduced; and the biotoxicity of the wastewater is reduced, so that the consumption of additional nutrient substances in a biochemical treatment method is reduced, the operation cost of a subsequent biochemical treatment method is reduced, and the effect of the subsequent biochemical treatment method of the wastewater is powerfully guaranteed.

Description

Technical Field

[0001] The present application belongs to the technical field of aniline wastewater treatment, and specifically relates to a method and device for treating aniline wastewater in a sequential batch mode. Background Art

[0002] Aniline compounds are a class of organic compounds containing aniline groups. They are important raw materials for the production of pesticides, rubber additives, sulfonamide drugs, etc. They are also intermediates for the production of dyes, varnishes, plastics, fragrances, films, etc. Therefore, there are often a large number of aniline and its derivatives in the production wastewater of these industries. The characteristics of this type of high-aniline wastewater are mainly complex costs, high pollutant concentrations, high oil content, high chroma, high biological toxicity, poor biodegradability, etc. (The biological toxicity of aniline substances is LC 100＝ 21.5mmol / L(24h)(Tetrahymena pearformis)). These characteristics lead to poor treatment effect of high-aniline wastewater directly using low-cost and economical biochemical treatment method, and the effluent is difficult to meet the standards; and in order to maintain the system stability of the biochemical treatment method from the biological impact of high-aniline wastewater, the consumption of additional nutrients increases, thereby greatly increasing the operating cost of the biochemical treatment method. Therefore, it is necessary to use physical and chemical treatment methods to first remove and degrade aniline and its derivatives in high-aniline wastewater in large quantities, reduce the biological toxicity of wastewater, improve biodegradability, and then use biochemical treatment methods for biochemical treatment, and finally meet the discharge standards.

[0003] The common physicochemical treatment methods for treating high-aniline wastewater on the market are mainly Fenton oxidation, extraction and adsorption. Among them, the disadvantages of Fenton oxidation are that it involves the use of many types of reagents and large amounts, high comprehensive operating costs, and poor effluent color; the disadvantage of the extraction method is that the process operation is too difficult and difficult for ordinary operators to complete, which is not conducive to practical application; the disadvantage of the adsorption method is that it is not suitable for high-aniline wastewater, and the adsorbent is easily lost into the subsequent biochemical treatment system, resulting in an increase in indicators such as effluent suspended solids.

[0004] In the related art, for example, the Chinese invention patent with application publication number CN104445711A records a method for treating aniline wastewater, which reduces the COD and aniline content of aniline wastewater by combining polycondensation reaction-Fenton-NaClO oxidation technology. In the polycondensation reaction process, it first "adds 0.01-0.5% of the wastewater mass of adsorbent to the aniline wastewater for 0.1-1h adsorption and oil removal, adjusts the pH value of the supernatant to 2-5 after separation, heats the supernatant to 60-70°C, mixes with formaldehyde solution, performs polycondensation reaction at 70-80°C, adjusts the pH to 6-9, and filters to obtain supernatant I". However, in the actual treatment of aniline wastewater, especially a large amount of aniline wastewater, heating the wastewater requires a special heating device on the one hand, and consumes a lot of energy on the other hand. Summary of the invention

[0005] 1. Problem to be solved

[0006] In view of the problems existing in the polycondensation reaction process in the above-mentioned prior art, the present application provides a method and device for treating aniline wastewater in a batch process, which can carry out the polycondensation reaction without heating, has a simple device and reduces energy consumption.

[0007] 2. Technical solution

[0008] In order to solve the above problems, the technical solutions adopted in this application are as follows:

[0009] The present application provides a method for treating aniline wastewater in a batch process, the method comprising the following steps:

[0010] S1, adding a pH regulator to adjust the pH of the aniline wastewater to 8-9, stirring and standing, and obtaining supernatant I; heavy oil in the high-aniline wastewater is precipitated due to the change in pH value, and is removed after standing and settling. Removing a large amount of heavy oil in the aniline wastewater can reduce its interference with subsequent chemical reactions and improve the treatment effect of subsequent biochemical processes;

[0011] S2, add formaldehyde to the supernatant I, stir, add pH adjuster after stirring to adjust pH value to 5-7, continue stirring until amine-aldehyde condensation is completed, let stand, and obtain supernatant II; using the principle of amine-aldehyde condensation, formaldehyde and aniline are condensed under acidic conditions through aldehyde group and imino group to synthesize polymers such as Mann's base and undergo covalent cross-linking to form flocs, which are removed after standing and settling.

[0012] Furthermore, the above-mentioned method for treating aniline wastewater by sequencing batch method further comprises the steps of:

[0013] S3, adding flocculant to the supernatant II, stirring, and then adding pH regulator to adjust the pH value to 5-7, stirring and then standing to obtain supernatant III; in step S2, although a large amount of precipitated amine-aldehyde condensation flocs are removed, there are still many suspended fine amine-aldehyde condensation flocs in the supernatant II, and the flocculant can enhance the polymerization bridge between the fine flocs to form larger flocs for precipitation and discharge, which can further remove residual aniline and its derivatives in the wastewater and reduce the concentration of organic matter in the wastewater.

[0014] Furthermore, the pH adjuster includes: dilute sulfuric acid (10%), sodium hydroxide solution (10%) and other commonly used pH adjusters in the art.

[0015] Furthermore, in the above S1, the pH of the aniline wastewater is adjusted to 8.5.

[0016] Furthermore, in the above S1, the stirring time is 10 to 20 minutes. Furthermore, in the above S1, the stirring time is 15 minutes.

[0017] Furthermore, in the above S1, the standing time is 15 to 45 minutes. Furthermore, in the above S1, the stirring time is 30 minutes.

[0018] Furthermore, in the above S2, the amount of formaldehyde added is such that the molar concentration of formaldehyde after addition is 1 to 3 times the molar concentration of aniline in the wastewater. Furthermore, in the above S2, the amount of formaldehyde added is such that the molar concentration of formaldehyde after addition is 2 times the molar concentration of aniline in the wastewater.

[0019] Furthermore, in the above S2, the first stirring time is 15 to 45 minutes. Furthermore, in the above S2, the first stirring time is 30 minutes.

[0020] Furthermore, in the above S2, the pH value is adjusted to 6.0 to provide acidic conditions for the reaction of polymers such as Mann's base.

[0021] Furthermore, in the above S2, the second stirring time is 15 to 45 minutes. Furthermore, in the above S2, the second stirring time is 30 minutes.

[0022] Furthermore, in the above S2, the standing time is 15 to 45 minutes. Furthermore, in the above S2, the stirring time is 30 minutes.

[0023] Furthermore, in the above S3, the flocculant includes: polyaluminum chloride (PAC) and / or polyferrous sulfate (PFS).

[0024] Furthermore, in the above S3, the amount of the flocculant added is 0.05% to 1% by volume of the wastewater. Furthermore, in the above S3, the amount of the flocculant added is 0.5% by volume of the wastewater.

[0025] Furthermore, in the above S3, the first stirring time is 5 to 15 minutes. Furthermore, in the above S3, the first stirring time is 10 minutes.

[0026] Furthermore, in the above S3, the pH value is adjusted to 6.0, which is close to neutrality to ensure good conditions for subsequent microbial treatment.

[0027] Furthermore, in the above S3, the second stirring time is 10 to 30 minutes. Furthermore, in the above S3, the second stirring time is 20 minutes.

[0028] Furthermore, in the above S2, the standing time is 15 to 45 minutes. Furthermore, in the above S2, the stirring time is 30 minutes.

[0029] The present application also provides a device for treating aniline wastewater in a batch process, the device comprising:

[0030] a first reaction vessel, a second reaction vessel, and a third reaction vessel;

[0031] The first reaction container is provided with a first stirring device, a first water inlet and a first water outlet;

[0032] The second reaction container is provided with a second stirring device, a second water inlet and a second water outlet;

[0033] The third reaction container is provided with a third stirring device, a third water inlet and a third water outlet;

[0034] The first water outlet is connected to the second water inlet pipeline, and the second water outlet is connected to the third water inlet pipeline; valves are arranged in the pipelines to control the inflow and outflow of inlet and outlet water.

[0035] Furthermore, in the above-mentioned device for treating aniline wastewater in a batch process, the bottoms of the first reaction container, the second reaction container and the third reaction container are all configured to be conical, and the conical bottom is provided with a valve and an opening, the valve is used to control the closing of the opening, and the conical bottom is conducive to removing the precipitation generated by standing.

[0036] The present application also provides an application of the above-mentioned device for treating aniline wastewater by sequencing batch method in treating aniline wastewater, and the application is to run the above-mentioned method for treating aniline wastewater by sequencing batch method in the device for treating aniline wastewater by sequencing batch method, specifically comprising: performing the above-mentioned S1 in a first reaction container, performing the above-mentioned S2 in a second reaction container, and performing the above-mentioned S3 in a third reaction container.

[0037] 3. Beneficial effects

[0038] Compared with the prior art, the present application has the following beneficial effects:

[0039] (1) The present invention provides a method and device for treating aniline wastewater in a batch process, which can carry out polycondensation reaction without heating. The device is simple and the energy consumption is significantly reduced. The entire treatment process only involves pH adjustment, reagent addition and stirring, which is simple to operate and easy for operators to use.

[0040] (2) The present invention provides a method and device for treating aniline wastewater in a batch process. The chemicals used only include pH regulator, formaldehyde (37%) and flocculant. The unit price of the chemicals is relatively low, and the operating cost is lower than that of other common physical and chemical treatment methods.

[0041] (3) The present invention provides a method and device for treating aniline wastewater in a batch process, which creatively adopts the physicochemical method of oil separation + phenolic aldehyde condensation + coagulation and sedimentation to treat high-aniline wastewater. First, a large amount of heavy oil substances in the wastewater are removed by oil separation treatment to reduce the interference with subsequent chemical reactions. Then, the principle of amine-aldehyde condensation is utilized to make formaldehyde and aniline condense into Schiff base through aldehyde group and imino group condensation to form flocs by covalent cross-linking. Finally, flocculants are added to enhance the polymerization bridge between fine flocs to form larger flocs for precipitation and discharge. Aniline and its derivatives in the wastewater can be removed in large quantities and with high efficiency, and the concentration of organic matter in the wastewater can be reduced. The biological toxicity of the wastewater is reduced, and the biodegradability is improved. The impact and negative impact on the subsequent biochemical treatment system are reduced, thereby reducing the consumption of added nutrients in the biochemical treatment method, reducing the operating cost of the subsequent biochemical treatment method, and effectively ensuring the effect of the subsequent biochemical treatment method of the wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a schematic diagram of a device for treating aniline wastewater in a sequencing batch manner.

[0043] Among them: 1 is the first reaction container, 2 is the second reaction container, 3 is the third reaction container, 4 is the first stirring device, 5 is the second stirring device, and 6 is the third stirring device. DETAILED DESCRIPTION

[0044] The present application is further described below in conjunction with specific embodiments.

[0045] It should be noted that the terms such as "upper", "lower", "left", "right", "middle", etc. cited in this specification are only for the convenience of description and are not used to limit the scope of implementation. Changes or adjustments to their relative relationships should be regarded as the scope of implementation of this application without substantially changing the technical content.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the term "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0047] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased from the market.

[0048] As used herein, the term "about" is used to provide flexibility and imprecision associated with a given term, measurement or value. The degree of flexibility for a particular variable can be easily determined by one skilled in the art.

[0049] As used herein, the term "at least one of" is intended to be synonymous with "one or more of." For example, "at least one of A, B, and C" expressly includes only A, only B, only C, and combinations of each thereof.

[0050] Concentration, amount and other numerical data can be presented in range format herein.It should be understood that such range format is only used for convenience and simplicity, and should be flexibly interpreted as not only including the numerical value clearly described as range limit, but also including all single numerical values ​​or sub-ranges contained in the range, just as each numerical value and sub-range are clearly described.For example, the numerical range of about 1 to about 4.5 should be interpreted as not only including the limit value of 1 to about 4.5 clearly described, but also including single numerals (such as 2,3,4) and sub-ranges (such as 1 to 3,2 to 4, etc.).The same principle is applicable to the scope of only narrating a numerical value, such as "less than about 4.5", which should be interpreted as including all the above-mentioned values ​​and ranges.In addition, no matter how the breadth of the described range or feature is, this explanation should be applicable.

[0051] Example 1

[0052] This embodiment provides a device and method for treating aniline wastewater in a sequencing batch mode.

[0053] In this embodiment, a schematic diagram of a sequential batch treatment device for aniline wastewater is shown in FIG. Figure 1 As shown, including:

[0054] A first reaction vessel (oil separator) 1, a second reaction vessel (amine-aldehyde condensation device) 2 and a third reaction vessel (coagulation and sedimentation device) 3;

[0055] The first reaction container 1 is provided with a first stirring device 4, a first water inlet and a first water outlet; the second reaction container 2 is provided with a second stirring device 5, a second water inlet and a second water outlet; the third reaction container 3 is provided with a third stirring device 6, a third water inlet and a third water outlet; the first water outlet is connected to the second water inlet pipe, and the second water outlet is connected to the third water inlet pipe; valves are provided in the pipes to control the inflow and outflow of inlet and outlet water;

[0056] The bottoms of the first reaction container 1 , the second reaction container 2 and the third reaction container 3 are all set to be conical, and the conical bottoms are provided with valves and openings, and the conical bottoms are conducive to removing the precipitation generated by standing.

[0057] This embodiment also provides a method for treating aniline wastewater in a sequencing batch process. The method is based on the above-mentioned device for treating aniline wastewater in a sequencing batch process, and comprises:

[0058] The high-aniline wastewater enters the oil separator 1 from the lower left side of the oil separator 1, and a pH regulator (10% dilute sulfuric acid) is added into the oil separator 1 to adjust the pH value of the aniline wastewater to 8.5, and stirred for 15 minutes. After the stirring, the wastewater is allowed to stand for 30 minutes. The heavy oil in the aniline wastewater is allowed to settle to the bottom of the oil separator 1 after standing, and is discharged through the valve and opening at the bottom of the oil separator 1;

[0059] The supernatant I after being treated by the oil separator 1 enters the amine-aldehyde condensation device 2 through the pipeline between the first water outlet and the second water inlet, and the corresponding formaldehyde (concentration of 37%) is added to the amine-aldehyde condensation device 2 according to twice the molar concentration of aniline in the wastewater, and stirred for 30 minutes to carry out the amine-aldehyde condensation reaction. After the stirring is completed, a pH regulator is added to adjust the pH value to 6.0, and the stirring is continued for 30 minutes until the amine-aldehyde condensation is completed. The mixture is allowed to stand for 30 minutes. At this time, a large amount of flocs produced by the amine-aldehyde condensation are allowed to stand and settle to the bottom of the amine-aldehyde condensation device 2, and are discharged through the bottom of the amine-aldehyde condensation device 2 through the valve and the opening;

[0060] The supernatant II after removing a large amount of precipitated amine-aldehyde condensation flocs enters the coagulation sedimentation device 3 through the pipeline between the second water outlet and the third water inlet, and a flocculant (PAC) with a mass volume ratio of 0.5% is added to the coagulation sedimentation device 3 and stirred for 10 minutes. Then, a pH adjuster is added to adjust the pH value to 6.0 and stirred for 20 minutes. The solution is allowed to settle for 30 minutes, and finally the flocs are precipitated from the bottom of the coagulation sedimentation device 3 through the valve and the opening, and the effluent is discharged from the upper right side of the coagulation sedimentation device 3.

[0061] Example 2

[0062] This embodiment provides a practical application of a sequencing batch method for treating aniline wastewater in the present application in treating aniline wastewater.

[0063] A high aniline wastewater (aniline concentration of 18605 mg / L and COD concentration of 59980 mg / L) enters the oil separator 1 from the lower left side of the oil separator 1, and a pH regulator (10% dilute sulfuric acid) is added into the oil separator 1 to adjust the pH value from 11.4 to 8.5, and stirred for 15 minutes. After the stirring, it is allowed to stand for 30 minutes. The heavy oil in the wastewater is allowed to settle to the bottom of the oil separator 1 after standing, and is discharged through the valve and opening at the bottom of the oil separator 1;

[0064] The supernatant I after oil separation enters the amine-aldehyde condensation device 2 through the pipeline between the oil separation device 1 and the amine-aldehyde condensation device 2. In the amine-aldehyde condensation device 2, 32.40 g / L of corresponding formaldehyde (concentration of 37%) is added according to twice the molar concentration of aniline in the wastewater, and stirred for 30 minutes to carry out amine-aldehyde condensation reaction. After stirring, a pH regulator is added to adjust the pH value from 8.5 to 6.0, and stirring is continued for 30 minutes until the amine-aldehyde condensation is completed. It is allowed to stand for 30 minutes. At this time, a large amount of flocs produced by the amine-aldehyde condensation are allowed to settle to the bottom of the amine-aldehyde condensation device 2 and discharged through the valve and opening at the bottom of the amine-aldehyde condensation device 2; after testing, the effluent aniline concentration is 2235 mg / L at this time, and the removal rate reaches 88.0%; the COD concentration is 15455 mg / L, and the removal rate reaches 74.2%;

[0065] The supernatant II after removing a large amount of precipitated amine-aldehyde condensation flocs enters the coagulation and sedimentation device 3 through the pipeline between the amine-aldehyde condensation device 2 and the coagulation and sedimentation device 3, 0.5% flocculant (PAC) is added to the coagulation and sedimentation device and stirred for 10 minutes, and then a pH adjuster is added to adjust the pH value from 5.77 to 6.0 and stirred for 20 minutes, and then allowed to settle for 30 minutes. Finally, the floc precipitate is discharged from the bottom of the coagulation and sedimentation device 3 through the valve and the opening, and the effluent is discharged from the upper right side of the coagulation and sedimentation device 3. After testing, the final effluent aniline concentration is 678 mg / L, and the removal rate reaches 96.4%; the COD concentration is 9413 mg / L, and the removal rate reaches 84.3%.

[0066] Example 3

[0067] This embodiment provides a practical application of a sequencing batch method for treating aniline wastewater in the present application in treating aniline wastewater.

[0068] A high aniline wastewater (aniline concentration of 25331 mg / L and COD concentration of 91600 mg / L) enters the device from the lower left side of the oil separator 1, and a pH regulator (10% dilute sulfuric acid) is added into the oil separator 2 to adjust the pH value from 11.62 to 8.5, and stirred for 15 minutes. After stirring, it is allowed to stand for 30 minutes. The heavy oil in the wastewater is allowed to settle to the bottom of the oil separator 1 after standing, and then discharged through the valve at the bottom of the oil separator 1;

[0069] The supernatant after oil separation enters the amine-aldehyde condensation device through the pipeline between the oil separation device and the amine-aldehyde condensation device, and the corresponding formaldehyde (concentration of 37%) 44.1g / L is added to the amine-aldehyde condensation device according to twice the molar concentration of aniline in the wastewater, and stirred for 30min to carry out amine-aldehyde condensation reaction. After stirring, a pH value regulator is added to adjust the pH value from 7.84 to 6.0, and stirring is continued for 30min until the amine-aldehyde condensation is completed. The mixture is allowed to stand for 30min. At this time, a large amount of flocs produced by the amine-aldehyde condensation are allowed to stand and settle to the bottom of the amine-aldehyde condensation device, and are discharged through the valve at the bottom of the amine-aldehyde condensation device 2; after testing, the effluent aniline concentration is 3078mg / L at this time, and the removal rate reaches 87.8%; the COD concentration is 26080mg / L, and the removal rate reaches 71.5%;

[0070] The supernatant after removing a large amount of precipitated amine-aldehyde condensation flocs enters the coagulation and sedimentation device through the pipeline between the amine-aldehyde condensation device 2 and the coagulation and sedimentation device 3, 0.5% flocculant is added to the coagulation and sedimentation device and stirred for 10 minutes, and then a pH adjuster is added to adjust the pH value from 6.17 to 6.0 and stirred for 20 minutes, and allowed to settle for 30 minutes. Finally, the floc precipitate is discharged from the bottom of the coagulation and sedimentation device through a valve, and the effluent is discharged from the upper right side of the coagulation and sedimentation device 3.

[0071] After testing, the effluent aniline concentration was 520 mg / L, and the removal rate reached 97.9%; the COD concentration was 15125 mg / L, and the removal rate reached 83.5%.

[0072] Comparative Example 1

[0073] This example provides the effect of different pH values ​​on the oil separation treatment of high-aniline wastewater.

[0074] A high aniline wastewater (aniline concentration of 25331 mg / L and COD concentration of 91600 mg / L) enters the device from the lower left side of the oil separator 1, and a pH regulator (10% dilute sulfuric acid) is added into the oil separator 2 to adjust the pH value from 11.62 to 10, and stirred for 15 minutes. After stirring, it is allowed to stand for 30 minutes. The heavy oil in the wastewater is allowed to settle to the bottom of the oil separator 1 after standing, and then discharged through the valve at the bottom of the oil separator 1;

[0075] The supernatant after oil separation enters the amine-aldehyde condensation device through the pipeline between the oil separation device and the amine-aldehyde condensation device. In the amine-aldehyde condensation device, the corresponding formaldehyde (concentration of 37%) 44.1g / L is added according to twice the molar concentration of aniline in the wastewater, and stirred for 30min to carry out amine-aldehyde condensation reaction. After stirring, a pH value regulator is added to adjust the pH value from 7.84 to 6.0, and stirring is continued for 30min until the amine-aldehyde condensation is completed. It is allowed to stand for 30min. At this time, a large amount of flocs produced by the amine-aldehyde condensation are allowed to settle to the bottom of the amine-aldehyde condensation device and discharged through the valve at the bottom of the amine-aldehyde condensation device 2. After testing, the effluent aniline concentration is 5859mg / L at this time, and the removal rate reaches 76.9%; the COD concentration is 42375mg / L, and the removal rate reaches 53.7%;

[0076] The supernatant after removing a large amount of precipitated amine-aldehyde condensation flocs enters the coagulation and sedimentation device through the pipeline between the amine-aldehyde condensation device 2 and the coagulation and sedimentation device 3, 0.5% flocculant is added to the coagulation and sedimentation device and stirred for 10 minutes, and then a pH adjuster is added to adjust the pH value from 6.17 to 6.0 and stirred for 20 minutes, and then allowed to settle for 30 minutes. Finally, the floc precipitate is discharged from the bottom of the coagulation and sedimentation device through a valve, and the effluent is discharged from the upper right side of the coagulation and sedimentation device 3; after testing, the effluent aniline concentration is 2352 mg / L, and the removal rate reaches 90.7%; the COD concentration is 23684 mg / L, and the removal rate reaches 74.1%.

[0077] Comparative Example 2

[0078] This example provides the effect of only adjusting the pH without standing to remove heavy oil on the treatment of high-aniline wastewater.

[0079] A high aniline wastewater (aniline concentration of 25331 mg / L and COD concentration of 91600 mg / L) enters the device from the lower left side of the oil separator 1, and a pH regulator (10% dilute sulfuric acid) is added in the oil separator 2 to adjust the pH value from 11.62 to 8.5;

[0080] Subsequently, without static sedimentation, the wastewater directly enters the amine-aldehyde condensation device through the pipeline between the oil separator and the amine-aldehyde condensation device, and the corresponding formaldehyde (concentration of 37%) 44.1 g / L is added to the amine-aldehyde condensation device according to twice the molar concentration of aniline in the wastewater, and stirred for 30 minutes to carry out amine-aldehyde condensation reaction. After stirring, a pH value regulator is added to adjust the pH value from 7.84 to 6.0, and stirring is continued for 30 minutes until the amine-aldehyde condensation is completed. The wastewater is allowed to stand for 30 minutes, at which time a large amount of flocs produced by the amine-aldehyde condensation are statically precipitated to the bottom of the amine-aldehyde condensation device and discharged through the valve at the bottom of the amine-aldehyde condensation device 2; after testing, the effluent aniline concentration is 45985 mg / L at this time, and the removal rate reaches 49.8%; the COD concentration is 8758 mg / L, and the removal rate reaches 65.4%;

[0081] The supernatant after removing a large amount of precipitated amine-aldehyde condensation flocs enters the coagulation and sedimentation device through the pipeline between the amine-aldehyde condensation device 2 and the coagulation and sedimentation device 3, 0.5% flocculant is added to the coagulation and sedimentation device and stirred for 10 minutes, and then a pH adjuster is added to adjust the pH value from 6.17 to 6.0 and stirred for 20 minutes, and then allowed to settle for 30 minutes. Finally, the floc precipitate is discharged from the bottom of the coagulation and sedimentation device through a valve, and the effluent is discharged from the upper right side of the coagulation and sedimentation device 3; after testing, the effluent aniline concentration is 4952 mg / L, and the removal rate reaches 80.5%; the COD concentration is 35368 mg / L, and the removal rate reaches 61.4%.

[0082] It can be seen that static oil separation treatment can improve the effect of aniline wastewater treatment.

[0083] Comparative Example 3

[0084] This embodiment provides a practical application of a sequencing batch method for treating aniline wastewater in the present application in treating aniline wastewater.

[0085] A high aniline wastewater (aniline concentration of 25331 mg / L and COD concentration of 91600 mg / L) enters the device from the lower left side of the oil separator 1, and a pH regulator (10% dilute sulfuric acid) is added into the oil separator 2 to adjust the pH value from 11.62 to 8.5, and stirred for 15 minutes. After stirring, it is allowed to stand for 30 minutes. The heavy oil in the wastewater is allowed to settle to the bottom of the oil separator 1 after standing, and then discharged through the valve at the bottom of the oil separator 1;

[0086] The supernatant after oil separation enters the amine-aldehyde condensation device through the pipeline between the oil separation device and the amine-aldehyde condensation device, the inlet water is heated to 60-70°C, and the corresponding formaldehyde (concentration of 37%) 44.1g / L is added to the amine-aldehyde condensation device according to twice the molar concentration of aniline in the wastewater, and stirred for 30min to carry out amine-aldehyde condensation reaction while ensuring that the reaction temperature is maintained at 70-80°C. After stirring, a pH value regulator is added to adjust the pH value from 7.84 to 6.0, and stirring is continued for 30min until the amine-aldehyde condensation is completed, and it is allowed to stand for 30min. At this time, a large amount of flocs produced by the amine-aldehyde condensation are allowed to stand and settle to the bottom of the amine-aldehyde condensation device, and discharged through the valve at the bottom of the amine-aldehyde condensation device 2. After testing, the effluent aniline concentration is 2985mg / L, and the removal rate reaches 88.2%; the COD concentration is 26854mg / L, and the removal rate reaches 70.7%;

[0087] The supernatant after removing a large amount of precipitated amine-aldehyde condensation flocs enters the coagulation and sedimentation device through the pipeline between the amine-aldehyde condensation device 2 and the coagulation and sedimentation device 3, 0.5% flocculant is added to the coagulation and sedimentation device and stirred for 10 minutes, and then a pH adjuster is added to adjust the pH value from 6.17 to 6.0 and stirred for 20 minutes, and then allowed to settle for 30 minutes. Finally, the floc precipitate is discharged from the bottom of the coagulation and sedimentation device through a valve, and the effluent is discharged from the upper right side of the coagulation and sedimentation device 3; after testing, the effluent aniline concentration is 486 mg / L, and the removal rate reaches 98.1%; the COD concentration is 16255 mg / L, and the removal rate reaches 82.3%.

[0088] It can be seen that heating during the amine-aldehyde reaction does not significantly improve the effect of aniline wastewater treatment.

Claims

1. A method for treating aniline wastewater in a sequencing batch process, characterized in that: The method comprises the following steps: S1, adding a pH regulator to adjust the pH of the aniline wastewater to 8-9, stirring and standing to obtain supernatant I; S2, add formaldehyde to the supernatant I, stir, add pH adjuster after stirring to adjust the pH value to 5-7, continue stirring until the amine aldehyde condensation is complete, let stand, and obtain supernatant II.

2. The method for treating aniline wastewater in a sequencing batch process according to claim 1, characterized in that: The method further comprises the steps of: S3, add flocculant to the supernatant II, stir, then add pH adjuster to adjust pH value to 5-7, stir and let stand to settle, and obtain supernatant III.

3. A method for treating aniline wastewater in a sequencing batch process according to claim 1 or 2, characterized in that: In S2, the amount of formaldehyde added is such that the molar concentration of formaldehyde after addition is 1 to 3 times the molar concentration of aniline in the wastewater.

4. The method for treating aniline wastewater in a sequencing batch process according to claim 3, characterized in that: In S3, the flocculant includes: polyaluminium chloride and / or polyferric sulfate; the added amount of the flocculant is 0.05% to 1% by volume of the wastewater.

5. The method for treating aniline wastewater in a sequencing batch process according to claim 4, characterized in that: The pH adjuster includes: dilute sulfuric acid or sodium hydroxide solution.

6. A method for treating aniline wastewater in a sequencing batch process according to claim 4 or 5, characterized in that: The stirring time in S1 is 10 to 20 minutes; the standing time is 15 to 45 minutes; and / or In S2, the first stirring time is 15 to 45 minutes; the second stirring time is 15 to 45 minutes; the standing time is 15 to 45 minutes; and / or In S3, the first stirring time is 5 to 15 minutes; the second stirring time is 10 to 30 minutes; and the standing time is 15 to 45 minutes.

7. A method for treating aniline wastewater in a sequencing batch process according to claim 6, characterized in that: In S1, the pH of the aniline wastewater is adjusted to 8.5; and / or In S2, the pH value is adjusted to 6.0; and / or In S3, the pH value is adjusted to 6.

0.

8. A device for treating aniline wastewater in a sequencing batch mode, characterized in that: The device comprises: a first reaction vessel, a second reaction vessel, and a third reaction vessel; The first reaction container is provided with a first stirring device, a first water inlet and a first water outlet; The second reaction container is provided with a second stirring device, a second water inlet and a second water outlet; The third reaction container is provided with a third stirring device, a third water inlet and a third water outlet; The first water outlet is connected to the second water inlet pipeline, and the second water outlet is connected to the third water inlet pipeline; a valve is arranged in the pipeline.

9. The device for treating aniline wastewater in a sequencing batch process according to claim 8, characterized in that: The bottoms of the first reaction container, the second reaction container and the third reaction container are all set to be conical, and the conical bottoms are provided with valves and openings.

10. Use of the device for treating aniline wastewater in a sequencing batch mode according to claim 8 or 9 in treating aniline wastewater, characterized in that: The application is: running a method for treating aniline wastewater in a sequencing batch process according to any one of claims 1 to 7 in the device for treating aniline wastewater in a sequencing batch process, wherein: S1 is carried out in a first reaction container, S2 is carried out in a second reaction container, and S3 is carried out in a third reaction container.

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