Aniline wastewater treatment system, treatment method and application

Abstract

The invention discloses an aniline wastewater treatment system, a treatment method and application. The aniline wastewater treatment system comprises a reactor with a reactor; the water inlet assembly comprises a water inlet pipe and a water inlet pump which are communicated with the reaction cavity; the filler is located in the reaction cavity and comprises a plurality of porous carriers, aerobic bacteria and facultative bacteria, the aerobic bacteria and the facultative bacteria are attached to the carriers, the aerobic bacteria are attached to the outer surfaces of the carriers, and the facultative bacteria are attached into holes of the carriers; the aeration assembly comprises a fan, an air inlet pipe for conveying air into the reaction cavity and an aeration head connected to the air inlet pipe, and the aeration head is located below the filler; the stirring assembly is used for stirring the wastewater in the reaction cavity; and the water outlet pipe is communicated with the reaction cavity. According to the aniline wastewater treatment system, by arranging the aeration assembly and the stirring assembly, alternate operation of nitration reaction and denitrification reaction can be achieved, and therefore the dual purposes of aniline degradation and efficient denitrification are achieved in the reactor.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to an aniline wastewater treatment system, a treatment method and an application. Background Art

[0002] Aniline wastewater is mainly produced in chemical processes such as dyeing (pigment), pharmaceuticals, printing and dyeing, and petroleum. Aniline compounds are toxic and highly toxic substances with "three-hazard" (carcinogenic, teratogenic, and mutagenic) effects. Improper contact can cause hypoxia in human tissues and damage the central nervous system, cardiovascular system, and other organs. In severe cases, it can cause death. If it is directly discharged without effective treatment and meeting the standards, it will cause serious pollution to the surrounding environment.

[0003] It is of great practical significance to carry out research on the prevention and treatment of aniline wastewater. The existing methods for treating large-scale aniline wastewater only focus on the removal of aniline and ignore the problem of releasing a large amount of ammonia nitrogen during the removal process.

[0004] In view of this, it is necessary to improve the existing aniline wastewater treatment system, treatment method and application to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide a novel aniline wastewater treatment system, treatment method and application.

[0006] In order to achieve the above-mentioned invention object, the present invention adopts the following technical scheme:

[0007] An aniline wastewater treatment system, comprising:

[0008] A reactor, including a reaction chamber;

[0009] A water inlet assembly, comprising a water inlet pipe communicating with the reaction chamber and a water inlet pump connected to the water inlet pipe;

[0010] A filler is located in the reaction chamber, the filler includes a plurality of porous carriers, aerobic bacteria and facultative anaerobic bacteria attached to the carriers, the aerobic bacteria are attached to the outer surface of the carriers, and the facultative anaerobic bacteria are attached to the pores of the carriers;

[0011] an aeration assembly, comprising a fan, an air inlet pipe for conveying gas into the reaction chamber, and an aeration head connected to the air inlet pipe, wherein the aeration head is located below the filler;

[0012] A stirring component is used to stir the wastewater in the reaction chamber;

[0013] A water outlet pipe is communicated with the reaction chamber.

[0014] In one embodiment, the porosity of the carrier is not less than 96%.

[0015] In one embodiment, the carrier includes a plurality of circumferential walls arranged at intervals, and connecting walls extending inward and outward directions and connecting adjacent circumferential walls, wherein the circumferential walls and the connecting walls are both porous structures, the aerobic bacteria are attached to the outer surfaces of the circumferential walls and the connecting walls, and the facultative anaerobic bacteria are attached to the pores of the circumferential walls and the connecting walls.

[0016] In one embodiment, the peripheral wall and the connecting wall divide the carrier into a plurality of through holes, and the area of ​​the through holes is 0.8 cm 2 ~1cm 2 .

[0017] In one embodiment, the stirring assembly includes a stirring reducer and a stirring paddle, part of the stirring paddle is located in the area where the filler is located, and part of the stirring paddle is located below the filler and above the aeration head.

[0018] A method for treating aniline wastewater based on the aniline wastewater treatment system comprises the following steps:

[0019] Start the water inlet pump to inject aniline wastewater into the reaction chamber of the reactor;

[0020] The aeration component and the stirring component are turned on alternately to perform nitrification treatment and denitrification treatment on the aniline wastewater alternately;

[0021] Close the aeration component and stirring component, and discharge the water after sedimentation.

[0022] In one embodiment, the amount of oxygen-containing gas delivered by the aeration assembly into the reaction chamber is 30 L / h to 40 L / h.

[0023] In one embodiment, during the process of alternately starting the aeration component and the stirring component, the operating time of the aeration component is longer than the operating time of the stirring component.

[0024] In one embodiment, alternately starting the aeration component and the stirring component comprises:

[0025] After the aeration component has been running for 1 to 2 hours, turn off the aeration component;

[0026] Start the stirring component immediately, and shut it down after it runs for 1 hour to 1.5 hours;

[0027] Run the above steps alternately until the total running time is 6 hours, then turn off the aeration component and the stirring component.

[0028] The application of the aniline wastewater treatment system or the aniline wastewater treatment method in the treatment of aniline-containing wastewater.

[0029] Application of the above aniline wastewater treatment system in the treatment of aniline-containing wastewater, or application of the above aniline wastewater treatment method in the treatment of aniline-containing wastewater.

[0030] The beneficial effects of the present invention are as follows: the aniline wastewater treatment system of the present invention can realize the alternating operation of nitrification reaction and denitrification reaction by arranging an aeration component and a stirring component, thereby achieving the dual purposes of aniline degradation and efficient nitrogen removal in the reactor. In addition, the present invention adopts a biological method to treat aniline wastewater, which has the advantages of no secondary pollution, low energy consumption and low economic cost compared with physical and chemical methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of the aniline wastewater treatment system of the present invention.

[0032] Figure 2 It is a schematic diagram of the structure of the filler of the present invention.

[0033] Among them, 100-aniline wastewater treatment system, 1-reactor, 2-water inlet assembly, 21-water inlet pipe, 22-water inlet pump, 3-filler, 31-carrier, 311-peripheral wall, 312-connecting wall, 4-aeration assembly, 41-fan, 42-inlet pipe, 43-aeration head, 5-stirring assembly, 51-stirring reducer, 52-stirring paddle, 6-water outlet pipe, DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] Please refer to Figure 1 and Figure 2 As shown, the present invention provides an aniline wastewater treatment system 100, comprising a reactor 1, a water inlet assembly 2 connected to the reactor 1, a filler 3 located in the reactor 1, an aeration assembly 4 for conveying oxygen-containing gas into the reactor 1, a stirring assembly 5 for driving the wastewater in the reactor 1 to circulate, and a water outlet pipe 6.

[0036] Specifically, the reactor 1 is preferably a fluidized bed reactor 1, which includes a reaction chamber. The reaction chamber provides a reaction site for wastewater treatment and cooperates with other structures or components to provide the required reaction conditions for aniline treatment.

[0037] The water inlet assembly 2 includes a water inlet pipe 21 connected to the reaction chamber and a water inlet pump 22 connected to the water inlet pipe 21. The water inlet pipe 21 is connected to the bottom of the filler 3 to let water in from the bottom, and the water inlet pump 22 controls the water inlet speed.

[0038] The water outlet pipe 6 is connected to the top of the reaction chamber, specifically connected to the top of the filler 3. After the wastewater is effectively treated by the filler 3, it is discharged from the top.

[0039] The filler 3 is located between the water inlet pipe 21 and the water outlet pipe 6, and is located in the middle of the reaction chamber in the height direction, which is the core place for aniline treatment.

[0040] The filler 3 includes a plurality of porous carriers 31, and aerobic bacteria and facultative anaerobic bacteria attached to the carriers 31. When the aeration component 4 is in operation, the aerobic bacteria decompose aniline to achieve nitrification reaction; when the aeration component 4 is closed and the stirring component 5 is in operation, the facultative anaerobic bacteria decompose ammonia nitrogen to achieve denitrification reaction, thereby achieving the dual purposes of aniline degradation and efficient denitrification in the reactor 1.

[0041] The carrier 31 is made of porous polyethylene material, which has the advantages of large specific surface area, easy biological attachment, non-degradation and good fluidization effect, and provides a good attachment environment for aerobic bacteria and facultative anaerobic bacteria.

[0042] In the present invention, the aerobic bacteria are attached to the outer surface of the carrier 31, and when the aeration assembly 4 is working, they come into contact with the oxygen-rich water body, and decompose the aniline in the wastewater into carbon dioxide and water through an oxidation reaction, and decompose ammonia nitrogen at the same time. The facultative anaerobic bacteria are attached to the pores of the carrier 31, and decompose nitrate nitrogen under anoxic conditions.

[0043] The carrier 31 is placed in activated sludge microorganisms with aerobic bacteria and facultative anaerobic bacteria, and the activated sludge microorganisms are attached to the inner or outer surface of the pores. The outer surface of the carrier 31 is in contact with the water body. When the aeration assembly 4 is working, the water body contains a large amount of oxygen, and an aerobic environment is formed on the outer surface of the carrier 31. The aerobic bacteria decompose the aniline in the wastewater into carbon dioxide and water through oxidation reaction, and grow and multiply to form a large number of aerobic bacteria attached to the outer surface of the filler 3; at the same time, a large amount of ammonia nitrogen is released during the degradation process of aniline.

[0044] The water flow in the pores of the carrier 31 is less flushed, and it is easy to form anoxic areas of the biofilm, so that facultative bacteria gather in the pores. When the aeration component 4 is closed, anoxic conditions are formed, and aerobic bacteria cannot grow and reproduce, while facultative bacteria can denitrify in the anoxic environment to degrade ammonia nitrogen, and grow and reproduce to form a large number of facultative bacteria attached to the pores of the filler 3.

[0045] In addition, the porosity of the carrier 31 is not less than 96%, the specific surface area is large, the contact area with the water body is large, and the aniline decomposition and ammonia nitrogen removal rates are high.

[0046] In one embodiment, if Figure 2 As shown, the carrier 31 includes a plurality of circumferential walls 311 arranged at intervals, and a connecting wall 312 extending in the inner and outer directions and connecting adjacent circumferential walls 311. Both the circumferential walls 311 and the connecting walls 312 are porous structures. The aerobic bacteria are attached to the outer surfaces of the circumferential walls 311 and the connecting walls 312, and the facultative anaerobic bacteria are attached to the holes of the circumferential walls 311 and the connecting walls 312.

[0047] The peripheral wall 311 and the connecting wall 312 divide the carrier 31 into a plurality of through holes, each of which has an area of ​​0.8 cm 2 ~1cm 2 The design of the through hole area, on the one hand, when the stirring component 5 is closed and only the aeration component 4 is opened, the wastewater is driven by gas to flow, and the flushing fluidity is relatively small. The structural combination of through holes and small pores is conducive to forming an anaerobic or anoxic environment in the pores; on the other hand, when the stirring component 5 is running, the water body has a large flow degree, and the water inside and outside the pores can be effectively exchanged, thereby improving the efficiency of anaerobic bacteria in decomposing ammonia nitrogen.

[0048] The aeration assembly 4 delivers oxygen-containing gas to the reaction chamber. The oxygen-containing gas includes any gas that can create an aerobic environment and adapt to the growth of aerobic bacteria, such as air, oxygen-rich gas, and ozone. The aeration device provides favorable conditions for aerobic bacteria attached to the outer surface of the filler 3 to decompose organic matter. Due to the special structure of the filler 3, the microorganisms inside are less affected by aeration, and the aeration will not cause a significant impact on the facultative aerobic bacteria inside the filler 3.

[0049] The aeration assembly 4 includes a fan 41, an air inlet pipe 42 for conveying gas into the reaction chamber, and an aeration head 43 connected to the air inlet pipe 42. When the fan 41 is started, oxygen-containing gas is provided to the reaction chamber to create an aerobic environment, which promotes aerobic bacteria to denitrify aniline. When the fan 41 is turned off, oxygen-containing gas is no longer provided to the reaction chamber, an anaerobic environment or anoxic environment is created, and facultative aerobic bacteria perform denitrification reaction on nitrogen-containing compounds to achieve efficient denitrification.

[0050] The aeration head 43 is located below the filler 3, so that the oxygen gas enters from the bottom of the reaction chamber. The oxygen gas enters the wastewater in the form of a high-speed jet, forming a gas-liquid mixed state, and drives the wastewater upward through the filler 3 under the action of the pressure difference / density difference, thereby achieving efficient degradation of aniline.

[0051] The stirring assembly 5 fully stirs the wastewater so that the microorganisms in the filler 3 are fully in contact with the wastewater. There is a trace amount of dissolved oxygen in the water body to provide aerobic bacteria for survival, and the anoxic environment formed inside the filler 3 provides favorable conditions for anaerobic bacteria to denitrify and degrade ammonia nitrogen, thereby achieving a denitrification reaction.

[0052] In one embodiment, the stirring assembly 5 includes a stirring reducer 51 and a stirring paddle 52, and the stirring assembly 5 is located in the middle of the container. In addition, part of the stirring paddle 52 is located in the area where the filler 3 is located, which can ensure effective contact with the anaerobic bacteria in the pores of the wastewater filler 3; part of the stirring paddle 52 is located below the filler 3 and above the aeration head 43, driving the wastewater to flow through the filler 3 and fully contact with the anaerobic bacteria, thereby improving the effect of the denitrification reaction.

[0053] The aeration assembly 4 and the stirring assembly 5 are set to operate in a selective manner, and the aeration assembly 4 and the stirring assembly 5 are operated alternately, and the aniline wastewater is subjected to nitrification treatment and denitrification treatment alternately. At the same time, in the alternating operation of aerobic and anaerobic, the aerobic bacteria attached to the outer surface of the filler 3 and the anaerobic bacteria inside will not die due to the alternation of different environments, but will only play the role of aerobic and anaerobic on each other, so as to achieve the dual purpose of aniline degradation and efficient denitrification.

[0054] Specifically, while aniline is degraded at a high speed in the aerobic section as the only carbon source, the released intermediate products are also rapidly decomposed and utilized by aerobic bacteria. It can be found that the introduction of intermittent aeration into the aniline degradation system can well stimulate the characteristics of the system to mainly perform nitrification reaction to remove ammonia nitrogen in the aerobic section and mainly perform denitrification reaction to remove nitrate nitrogen in the anoxic section. The nitrite nitrogen in the system also tends to increase and decrease alternately with the progress of nitrification and denitrification reactions, and the alternating changes in its mass concentration produce fluctuations between 0.4 mg / L and 1 mg / L. In an anaerobic environment where aeration component 4 stops aeration, the nitrate nitrogen or nitrite nitrogen released by the degraded aniline in the wastewater is reduced to nitrogen (N2) through a series of denitrification reactions, thereby achieving the purpose of efficient denitrification.

[0055] Based on the aniline wastewater treatment system 100, the present invention further provides an aniline wastewater treatment method, comprising the following steps: starting the water inlet pump 22 to inject the aniline wastewater into the reaction chamber of the reactor 1; alternately opening the aeration component 4 and the stirring component 5 to alternately perform nitrification treatment and denitrification treatment on the aniline wastewater; closing the aeration component 4 and the stirring component 5 to discharge the water after sedimentation.

[0056] The aeration component 4 delivers 30L / h to 40L / h of oxygen-containing gas into the reaction chamber, which can meet the needs of aerobic bacteria and effectively decompose aniline without affecting facultative anaerobic bacteria.

[0057] During the process of alternately starting the aeration component 4 and the stirring component 5, the operation time of the aeration component 4 is greater than the operation time of the stirring component 5. Such a design can increase the aerobic time to degrade aniline, and advance the start time of nitrification to produce sufficient nitric nitrogen substrate, thereby further increasing the rate of denitrification reaction and improving the system's ability to degrade aniline and denitrify simultaneously as a whole.

[0058] Alternatingly opening the aeration component 4 and the stirring component 5 includes: after the aeration component 4 has been running for 1 hour to 2 hours, closing the aeration component 4; immediately starting the stirring component 5, and after the stirring component 5 has been running for 1 hour to 1.5 hours, closing the stirring component 5; alternately performing the above steps until the total running time is 6 hours, closing the aeration component 4 and the stirring component 5.

[0059] The present invention controls the alternation time of the aerobic environment and the anaerobic environment by controlling the operation time of the aeration component 4 and the stirring component 5. The aerobic bacteria attached to the surface of the filler 3 and the anaerobic bacteria inside the filler 3 will not die due to the alternation of different environments. Instead, the aerobic and anaerobic effects will be exerted on each other, thereby achieving the dual purposes of aniline degradation and efficient denitrification.

[0060] After closing the aeration assembly 4 and the stirring assembly 5, the water is discharged after settling for 45min to 60min, and then the water is discharged, and the water exchange ratio is 30%. The water exchange ratio means that the water occupies 30% of the volume of the reactor 1 to ensure the quality of the discharged water.

[0061] The aniline wastewater treatment system 100 or the aniline wastewater treatment method of the present invention can be used to treat aniline-containing wastewater, and has a good treatment effect on aniline-containing wastewater generated by chemical engineering such as dyes (pigments), pharmaceuticals, printing and dyeing, and petroleum.

[0062] In summary, the novel aniline wastewater treatment system 100 of the present invention can realize the alternating operation of nitrification reaction and denitrification reaction by providing the aeration component 4 and the stirring component 5, thereby achieving the dual purpose of aniline degradation and efficient nitrogen removal in the reactor 1. In addition, the present invention adopts biological method to treat aniline wastewater, which has the advantages of no secondary pollution, low energy consumption and low economic cost compared with physical and chemical methods.

[0063] A specific implementation is provided below to describe the aniline wastewater treatment method of the present invention in detail.

[0064] A dye wastewater from Zhejiang was used as the experimental object. A portion of the biological sludge was retrieved from the aeration tank in the A2 / O process for treating the wastewater. After 24 hours of anaerobism, the sludge concentration was adjusted to about 3500 mg / L. A porous polyethylene filler 3 was added, and after stirring evenly, it was put into the reactor 1 for testing. The original sewage from the dye factory was used as the experimental influent. The aniline content of the original sewage was 185 mg / L, the ammonia nitrogen content was 10 mg / L, and the total nitrogen content was 50 mg / L.

[0065] The volume of the reaction chamber is 1L. Water is slowly introduced through the water inlet pump 22. The aeration component 4 and the stirring component 5 are opened alternately. After a period of alternating operation, aerobic bacteria are attached to the outer surface of the filler 3, and facultative anaerobic bacteria are attached to the pores of the filler 3.

[0066] The operation cycle of reactor 1 was set as follows: water inlet 5 min, aerobic 1.5 h, anoxic 1.5 h, aerobic 1.5 h, anoxic 1.5 h, sedimentation 1 h, water outlet 5 min, water exchange ratio 30%, and a total of 5 cycles.

[0067] After the above process treatment, the water quality indicators of each process section are shown in the table below.

[0068] Process wastewater Aniline(mg / L) Ammonia nitrogen (mg / L) Total nitrogen (mg / L) Water Intake 185 10 50 Cycle 1 18 5 15 Cycle 2 18 6 16 Cycle 3 16 5 15 Cycle 4 15 4 13 Cycle 5 15 4 12

[0069] Ammonia nitrogen is released during the degradation of aniline. We achieve nitrification and denitrification through intermittent aeration, and enhance the reaction by adding polyethylene filler 3 with a large specific surface area, so as to achieve efficient denitrification in reactor 1.

[0070] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. An aniline wastewater treatment system, characterized in that: include: A reactor, including a reaction chamber; A water inlet assembly, comprising a water inlet pipe communicating with the reaction chamber and a water inlet pump connected to the water inlet pipe; A filler is located in the reaction chamber, the filler includes a plurality of porous carriers, aerobic bacteria and facultative anaerobic bacteria attached to the carriers, the aerobic bacteria are attached to the outer surface of the carriers, and the facultative anaerobic bacteria are attached to the pores of the carriers; an aeration assembly, comprising a fan, an air inlet pipe for conveying gas into the reaction chamber, and an aeration head connected to the air inlet pipe, wherein the aeration head is located below the filler; A stirring component is used to stir the wastewater in the reaction chamber; A water outlet pipe is communicated with the reaction chamber.

2. The aniline wastewater treatment system according to claim 1, characterized in that: The porosity of the carrier is not less than 96%.

3. The aniline wastewater treatment system according to claim 1, characterized in that: The carrier includes a plurality of circumferential walls arranged at intervals and connecting walls extending inward and outward directions and connecting adjacent circumferential walls. Both the circumferential walls and the connecting walls are porous structures. The aerobic bacteria are attached to the outer surfaces of the circumferential walls and the connecting walls, and the facultative anaerobic bacteria are attached to the pores of the circumferential walls and the connecting walls.

4. The aniline wastewater treatment system according to claim 3, characterized in that: The peripheral wall and the connecting wall divide the carrier into a plurality of through holes, each of which has an area of ​​0.8 cm 2 ~1cm 2 .

5. The aniline wastewater treatment system according to claim 1, characterized in that: The stirring assembly includes a stirring reducer and a stirring paddle, part of the stirring paddle is located in the area where the filler is located, and part of the stirring paddle is located below the filler and above the aeration head.

6. A method for treating aniline wastewater based on the aniline wastewater treatment system according to any one of claims 1 to 5, characterized in that: The steps include: Start the water inlet pump to inject aniline wastewater into the reaction chamber of the reactor; The aeration component and the stirring component are turned on alternately to perform nitrification treatment and denitrification treatment on the aniline wastewater alternately; Close the aeration component and stirring component, and discharge the water after sedimentation.

7. The method for treating aniline wastewater according to claim 6, characterized in that: The amount of oxygen-containing gas delivered by the aeration component to the reaction chamber is: 30L / h~40L / h.

8. The method for treating aniline wastewater according to claim 6, characterized in that: During the process of alternately starting the aeration component and the stirring component, the operating time of the aeration component is longer than the operating time of the stirring component.

9. The method for treating aniline wastewater according to claim 6, characterized in that: The alternating aeration assembly and stirring assembly include: After the aeration component has been running for 1 to 2 hours, turn off the aeration component; Start the stirring component immediately, and shut it down after it runs for 1 hour to 1.5 hours; Run the above steps alternately until the total running time is 6 hours, then turn off the aeration component and the stirring component.

10. Use of the aniline wastewater treatment system according to any one of claims 1 to 5 or the aniline wastewater treatment method according to any one of claims 6 to 9 in the treatment of aniline-containing wastewater.

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