A device and method for treating ibuprofen-containing wastewater

Abstract

The application discloses a device and method for treating wastewater containing ibuprofen, and belongs to the field of wastewater treatment. The device comprises a low-oxygen aeration tank, a variable-oxygen aeration tank, a sludge conveying pipe connecting the two aeration tanks, and an adjustable air pump arranged at the bottom of the aeration tank for aeration of the system. The method comprises the following steps: controlling the dissolved oxygen in the two tanks and closing the sludge conveying pipe valve in a non-response state, and normally treating wastewater in the two tanks; when the liquid chromatography detects that the concentration of ibuprofen in the influent reaches a certain concentration, closing the influent and effluent valves of the low-oxygen aeration tank to make the sludge in the tank in a starvation state, adjusting the dissolved oxygen in the variable-oxygen aeration tank to make the sludge in the tank in an aerobic condition to maintain the treatment effect, periodically conveying the starved sludge in the low-oxygen aeration tank into the variable-oxygen aeration tank through the sludge conveying pipe to efficiently degrade ibuprofen, and conveying the sludge in the secondary sedimentation tank into the low-oxygen aeration tank; after the reactor responds, the low-oxygen aeration tank only performs aeration, and at this time, the sludge enters a starvation state after consuming the nutrients in the wastewater. The operation process of the application is simple, the aeration tank is fully utilized, and the application potential is huge.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of sewage treatment, and particularly relates to a device and method for treating wastewater containing ibuprofen. BACKGROUND

[0002] Active sludge floc is a biological community formed by adhesion of extracellular polymers of aerobic microorganisms to a skeleton composed of filamentous bacteria. Active sludge utilizes the metabolic action of aerobic microorganisms in the active sludge to degrade and remove organic matter in wastewater, thereby achieving the effect of purifying wastewater. Compared with other physical and chemical processes, the active sludge process has low operating cost, large treatment capacity, and relatively simple structure, but still exposes some shortcomings in the process of operation, such as high energy consumption, large amount of residual sludge, and sludge bulking.

[0003] In order to solve the above problems, a low-dissolved oxygen active sludge process emerges as the times require. In the low-dissolved oxygen active sludge process, the dissolved oxygen in the aeration tank is artificially controlled, so that the filamentous bacteria can be maintained at an appropriate abundance, so that the net-like structure formed by the filamentous bacteria can effectively capture suspended solids in the wastewater, and will not cause the sludge to produce malignant filamentous bulging. At the same time, under the condition of low dissolved oxygen, the sludge yield is also reduced, thereby saving the sludge treatment cost. Under the condition of low dissolved oxygen, there are three environments of oxygen, facultative and anoxic inside the sludge floc from outside to inside, and nitrifying bacteria and nitrosation bacteria can coexist in the sludge floc and cooperate with each other, and even realize short-cut nitrification and denitrification, thereby ensuring efficient removal of ammonia nitrogen.

[0004] Ibuprofen belongs to non-steroidal anti-inflammatory analgesic drugs, which can reduce inflammation and pain by inhibiting the activity of cyclooxygenase (COX), and can also act on the hypothalamic temperature regulation center, so as to make the body temperature return to normal, and can be used as an analgesic and an antipyretic and anti-inflammatory drug.

[0005] Studies have shown that after the drug is ingested by the human body, it is not all absorbed and utilized, and finally excreted in the original form with urine or feces and flows into the sewage treatment plant through the sewage treatment system. As early as the 1980s, ibuprofen was detected in different water bodies and sewage treatment plants in various countries and regions. Ibuprofen is not completely degraded in the sewage treatment process and enters the natural water body. Continuous input leads to pseudo-persistence of ibuprofen. Although the environmental residue level is low, long-term exposure still causes chronic and cumulative toxicity to microorganisms, invertebrates and humans. Studies have shown that ibuprofen entering the sewage treatment system will affect the enzyme activity and respiration of microorganisms, interfere with the normal metabolism of microorganisms, especially for low-dissolved oxygen activated sludge method, which will seriously affect the treatment effect of low-dissolved oxygen activated sludge method, and even cause the collapse of the biological treatment system. Therefore, it is necessary to develop a new process that can cope with the impact of ibuprofen on activated sludge while retaining the advantages of low-oxygen activated sludge method and achieve efficient removal of ibuprofen. SUMMARY

[0006] Based on the above problems, the purpose of the present application is to provide a device and method for treating wastewater containing ibuprofen. The device and method of the present application can achieve efficient removal of ibuprofen in water.

[0007] To achieve the above-mentioned purpose, the present application provides the following technical solutions.

[0008] In the scheme of the present application, the activated sludge is divided into two parts. In the non-response state, the activated sludge is kept in a low-oxygen state. When ibuprofen is detected in the influent, one part of the activated sludge is subjected to appropriate starvation treatment to enrich the sludge with high-efficiency ibuprofen-degrading function, and the other part of the sludge is kept in a condition with a higher dissolved oxygen concentration. The starved sludge obtained by enrichment is used to treat wastewater containing ibuprofen. On the one hand, it can cope with the inhibition of ibuprofen on the respiration of activated sludge to ensure the removal effect of conventional pollutants, and on the other hand, the starved sludge has a higher degradation efficiency for ibuprofen, thereby achieving efficient removal of ibuprofen in wastewater.

[0009] Therefore, one embodiment of the present application provides a device for treating wastewater containing ibuprofen, comprising:

[0010] A low-oxygen aeration tank and a variable-oxygen aeration tank are arranged in parallel, and a secondary sedimentation tank is connected in series with the low-oxygen aeration tank and the variable-oxygen aeration tank, respectively;

[0011] Adjustable air pumps, two of which are arranged at the bottom of the low-oxygen aeration tank and the variable-oxygen aeration tank, respectively, for aeration;

[0012] The device for treating wastewater containing ibuprofen comprises two dissolved oxygen control devices, each of which is connected with one of the adjustable air pumps and monitors the dissolved oxygen concentration in the low-oxygen aeration tank and the variable-oxygen aeration tank, and is used for adjusting the dissolved oxygen concentration in the two aeration tanks.

[0013] The device for treating wastewater containing ibuprofen provided by the above-mentioned embodiment of the application comprises a low-oxygen aeration tank and a variable-oxygen aeration tank, and the low-oxygen aeration tank and the variable-oxygen aeration tank are connected in parallel through a sludge conveying pipe.

[0014] The device for treating wastewater containing ibuprofen provided by the above-mentioned embodiment of the application comprises a low-oxygen aeration tank and a variable-oxygen aeration tank, and the low-oxygen aeration tank and the variable-oxygen aeration tank are connected in parallel through a sludge conveying pipe.

[0015] The device for treating wastewater containing ibuprofen provided by the above-mentioned embodiment of the application comprises a low-oxygen aeration tank and a variable-oxygen aeration tank, and the low-oxygen aeration tank and the variable-oxygen aeration tank are connected in parallel through a sludge conveying pipe.

[0016] The device for treating wastewater containing ibuprofen provided by the above-mentioned embodiment of the application comprises a low-oxygen aeration tank and a variable-oxygen aeration tank, and the low-oxygen aeration tank and the variable-oxygen aeration tank are connected in parallel through a sludge conveying pipe.

[0017] S1: When no ibuprofen is detected in the influent or the concentration of ibuprofen does not reach a certain threshold, the device is in a non-response state, the valves of the influent and effluent of the low-oxygen aeration tank, the first sludge collecting pipe and the first sludge backflow pipe are opened, and the valve of the sludge conveying pipe is closed.

[0018] S2: When a certain concentration of ibuprofen is detected in the influent, the device enters a response state, the valves of the influent and effluent of the low-oxygen aeration tank and the first sludge collecting pipe are closed, the valve of the sludge conveying pipe is opened, the sludge in the low-oxygen aeration tank is in a starvation state, the sludge in the secondary sedimentation tank is supplemented to the low-oxygen aeration tank through the first sludge backflow pipe, and the starvation sludge in the low-oxygen aeration tank is conveyed to the variable-oxygen aeration tank through the sludge conveying pipe.

[0019] According to the method for treating wastewater containing ibuprofen provided in the above embodiment of the present application, the sludge concentration of the low-oxygen aeration tank and the variable-oxygen aeration tank in step S1 is between 4000 and 6000 mg / L; and the dissolved oxygen of the low-oxygen aeration tank and the variable-oxygen aeration tank is between 1.0 and 1.5 mg / L.

[0020] According to the method for treating wastewater containing ibuprofen provided in the above embodiment of the present application, the sludge concentration of the low-oxygen aeration tank in step S2 is between 5000 and 10000 mg / L; the sludge concentration of the variable-oxygen aeration tank is between 2000 and 4000 mg / L; the dissolved oxygen of the low-oxygen aeration tank is between 1.0 and 1.5 mg / L; and the dissolved oxygen of the variable-oxygen aeration tank is 3.0±0.5 mg / L.

[0021] In steps S1 and S2, too low sludge concentration of the low-oxygen aeration tank will reduce the efficiency of enriching the starved sludge, and too high sludge concentration of the variable-oxygen aeration tank will easily lead to sludge loss and digestion.

[0022] In step S1, the dissolved oxygen content of the low-oxygen aeration tank and the variable-oxygen aeration tank is low, the sludge bulking caused by filamentous bacteria can be controlled within a reasonable range, and the effluent quality is not deteriorated.

[0023] In step S1, too low dissolved oxygen of the low-oxygen aeration tank will inhibit the aerobic process, and too high dissolved oxygen will waste energy; and the ibuprofen in the influent of the variable-oxygen aeration tank will inhibit the sludge respiration rate, and too low dissolved oxygen will lead to the decrease of sludge treatment efficiency and even cause the collapse of the biological treatment system.

[0024] According to the method for treating wastewater containing ibuprofen provided in the above embodiment of the present application, the hydraulic retention time of the low-oxygen aeration tank and the variable-oxygen aeration tank in step S1 is 10 to 12 hours.

[0025] According to the method for treating wastewater containing ibuprofen provided in the above embodiment of the present application, the hydraulic retention time of the variable-oxygen aeration tank in step S2 is 12 to 15 hours; the sludge retention time of the low-oxygen aeration tank is 3 to 5 days, that is, 1 / 5 to 1 / 3 of the sludge is inoculated into the variable-oxygen aeration tank through a sludge conveying pipe every day, and the corresponding sludge is supplemented from the low-oxygen aeration tank to keep the amount of sludge in the variable-oxygen aeration tank unchanged.

[0026] According to the method for treating wastewater containing ibuprofen provided in the above embodiment of the present application, the threshold value in step S1 is 100 μg / L.

[0027] According to the method for treating wastewater containing ibuprofen provided in the above embodiment of the present application, the lower limit of the ibuprofen concentration in the influent in step S2 is 100 μg / L. Higher ibuprofen concentration will affect the activity of the activated sludge.

[0028] In the non-response state, the dissolved oxygen in the two tanks (low-oxygen aeration tank and variable-oxygen aeration tank) is controlled to be 1.0-1.5 mg / L, and the sludge conveying pipe valve is closed, and the two tanks normally treat wastewater; when it is detected that the concentration of ibuprofen in the influent is higher than 100 μg / L, the low-oxygen aeration tank influent and effluent valves are closed to make the sludge in the tank in a starvation condition, the dissolved oxygen in the variable-oxygen aeration tank is adjusted to 3±0.5 mg / L to make the sludge in the tank in an aerobic condition to maintain the treatment effect, and at the same time, the starvation sludge in the low-oxygen aeration tank is periodically sent into the variable-oxygen aeration tank through the sludge conveying pipe to treat ibuprofen, and the sludge in the secondary sedimentation tank is sent into the low-oxygen aeration tank to make the sludge in a starvation state.

[0029] Compared with the prior art, the present application has the following beneficial effects:

[0030] (1) The present application uses low-oxygen activated sludge process in the non-response state, which can effectively reduce energy consumption and reduce sludge bulking.

[0031] (2) The present application effectively utilizes the aeration tank. In the non-response state, the two aeration tanks can be used as biological treatment units of the low-oxygen activated sludge process to treat wastewater; when the influent contains a certain amount of ibuprofen, the process flow can be changed in a short time and respond in time to avoid the decline or even collapse of the system treatment efficiency due to the impact of ibuprofen on the activated sludge.

[0032] (3) In the response state, the sludge moves in space to make the state in a "starvation-treatment-re-starvation" cycle, so even if the treatment unit is only the variable-oxygen aeration tank, the utilization rate of the sludge can be maintained, so the treatment effect will not be greatly reduced.

[0033] (4) In the non-response state, the present application uses low-dissolved-oxygen activated sludge process, and the sludge yield is greatly reduced compared with the traditional activated sludge process. In the response state, the process of enriching starvation sludge in the low-oxygen aeration tank also causes the consumption of organic matter in the sludge and the digestion of part of the sludge, thereby greatly reducing the amount of residual sludge in the whole system.

[0034] (5) The present application divides the sludge into two parts, and when the influent contains ibuprofen, one part of the sludge is treated in a starvation state, and the other part is used to treat wastewater containing ibuprofen, and the sludge in the two tanks is rotated through the sludge conveying pipe, which is simple in operation and fully utilizes the aeration tank, and has high practical value. The present application can effectively improve the removal efficiency of ibuprofen by the activated sludge in the aeration tank by enriching starvation sludge, and can avoid the steps of purchasing and adding ibuprofen-degrading bacteria, and reduce the cost of purchasing and storing functional bacteria. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 It is a schematic diagram of the device for treating wastewater containing ibuprofen according to the present application.

[0036] Figure 2 COD removal rate vs. dissolved oxygen in Example 1;

[0037] Figure 3 Ammonia nitrogen removal rate vs. dissolved oxygen in Example 1;

[0038] Figure 4 COD and ammonia nitrogen removal rate vs. ibuprofen concentration in Example 2;

[0039] Figure 5 COD, ammonia nitrogen and ibuprofen removal rate vs. time in Example 3.

[0040] In the figure: 10, 11, adjustable air pump; 20, 21, dissolved oxygen control device; 100, low-oxygen aeration tank; 101, variable-oxygen aeration tank; 102, secondary sedimentation tank; 200, low-oxygen aeration tank water inlet pipe; 201, variable-oxygen aeration tank water inlet pipe; 210, first sludge collection pipe; 211, second sludge collection pipe; 212, drain pipe; 300, sludge conveying pipe; 312, sludge discharge pipe; 320, first sludge return pipe; 321, second sludge return pipe. Embodiment

[0041] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work belong to the scope of protection of the present application.

[0042] Unless otherwise defined, 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; the term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0043] Unless otherwise specified, the specific conditions in the examples are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are not specified by the manufacturer, but are conventional products that can be purchased on the market.

[0044] As used herein, the term "about" is used to provide flexibility to a given term, measurement, or value. The degree of flexibility of a particular variable can be readily determined by one of skill in the art.

[0045] The present application will be further described below in conjunction with specific examples.

[0046] As Figure 1As shown, the preferred embodiment of the present application provides a device for treating wastewater containing ibuprofen, which comprises a low-oxygen aeration tank 100 and a variable-oxygen aeration tank 101 connected in parallel, and a secondary sedimentation tank 102 connected in series with the low-oxygen aeration tank 100 and the variable-oxygen aeration tank 101, respectively. Two adjustable air pumps are provided, shown as 10 and 11, respectively, and arranged at the bottom of the low-oxygen aeration tank 100 and the variable-oxygen aeration tank 101, respectively. The adjustable air pumps serve two purposes: 1. to greatly change the dissolved oxygen concentration in the aeration tank, such as from 1 mg / L to 3 mg / L; 2. to maintain the dissolved oxygen in the aeration tank within a stable range, which is generally achieved by using an automatic monitoring system to control the aeration amount through negative feedback, more specifically, by using a PID algorithm to obtain the required aeration amount, comparing the difference between the required aeration amount and the measured value, and then increasing or decreasing the aeration amount of the air pump to achieve stable control of the dissolved oxygen in the aeration tank; the dissolved oxygen control device also comprises two, shown as 20 and 21, respectively, which are connected with the adjustable air pumps 10 and 11 and monitor the dissolved oxygen concentration in the low-oxygen aeration tank 100 and the variable-oxygen aeration tank 101, respectively, for adjusting the dissolved oxygen in the two aeration tanks. Preferably, each of the dissolved oxygen control devices 20 and 21 comprises a dissolved oxygen probe for adjusting the dissolved oxygen in the aeration tank (low-oxygen aeration tank 100 or variable-oxygen aeration tank 101) and a controller connected with the adjustable air pump to control the aeration amount of the adjustable air pump. The low-oxygen aeration tank 100 and the variable-oxygen aeration tank 101 are connected in parallel through a sludge conveying pipe 300. The low-oxygen aeration tank 100 further comprises a low-oxygen aeration tank inlet pipe 200. The variable-oxygen aeration tank 101 further comprises a variable-oxygen aeration tank inlet pipe 201. The secondary sedimentation tank 102 comprises a sludge discharge pipe 312 and a water discharge pipe 212. The secondary sedimentation tank 102 is connected in series with the low-oxygen aeration tank 100 through a first sludge collection pipe and a first sludge return pipe, and is connected in series with the variable-oxygen aeration tank through a second sludge collection pipe and a second sludge return pipe. The sludge age of the low-oxygen aeration tank 100 and the variable-oxygen aeration tank is 20 d, and a too long sludge age will cause sludge aging and reduce the treatment effect; a too short sludge age will cause a continuous decrease in sludge concentration.

[0047] In the non-response state, the sludge conveying pipe 300 is closed, the sewage enters the low-oxygen aeration tank 100 and the variable-oxygen aeration tank 101 through the water inlet, stays for a certain period of time, and then the treated sludge-water mixture enters the secondary sedimentation tank 102 through the water outlet, part of the settled sludge in the secondary sedimentation tank is returned to the two aeration tanks through the first and second sludge return pipes 320 and 321, the remaining sludge is discharged through the sludge discharge pipe 312, and the supernatant is discharged through the drain pipe 212; when the ibuprofen content in the influent (designated as the ibuprofen content in the effluent of the settling tank or the influent of the low-oxygen aeration tank) reaches a certain level, the inlet and outlet valve of the low-oxygen aeration tank is closed, part of the sludge in the low-oxygen aeration tank enters the variable-oxygen aeration tank through the sludge conveying pipe 300, and the sludge conveying period is about 3-5 days, the dissolved oxygen in the variable-oxygen aeration tank 101 is adjusted to 3.0±0.5 mg / L, and the wastewater containing ibuprofen enters the variable-oxygen aeration tank 101 through the water inlet and is mixed with the starved sludge, after a period of time, the treated sludge-water mixture enters the secondary sedimentation tank 102 through the second sludge collection pipe 211, the supernatant is discharged through the drain pipe 212, and part of the settled sludge is returned to the low-oxygen aeration tank 101 through the first sludge return pipe 320 to supplement the sludge lost in the low-oxygen aeration tank 100, and part of the settled sludge is discharged through the sludge discharge pipe 312.

[0048] The operation is as described above. In the non-response state, the sludge concentrations in the low-oxygen aeration tank and the variable-oxygen aeration tank are in the range of 4000-6000 mg / L, the hydraulic retention time is 10-12 h, and the sludge age is 20 d; in the response state, the sludge concentration in the low-oxygen aeration tank is controlled in the range of 5000-10000 mg / L, the dissolved oxygen is maintained at 1.0-1.5 mg / L, the sludge discharge period is 3-5 days, the sludge concentration in the variable-oxygen aeration tank is controlled in the range of 2000-4000 mg / L, and the dissolved oxygen is maintained at 3.0±0.5 mg / L to cope with the inhibition of ibuprofen on sludge respiration, and the hydraulic retention time is 12-15 h.

[0049] The above settings are because too low sludge concentration in the low-oxygen aeration tank will reduce the efficiency of enriching starved sludge, and too high sludge concentration in the variable-oxygen aeration tank will easily lead to sludge loss and digestion. When the dissolved oxygen concentration in the low-oxygen aeration tank and the variable-oxygen aeration tank is 1-1.5 mg / L, the sludge bulking caused by filamentous bacteria can be controlled within a reasonable range, and at the same time, the effluent quality can be guaranteed not to deteriorate. Too low dissolved oxygen in the low-oxygen aeration tank will inhibit the aerobic process, and too high dissolved oxygen will waste energy. The ibuprofen in the influent of the variable-oxygen aeration tank will inhibit the sludge respiration rate, and too low dissolved oxygen will lead to a decrease in sludge treatment efficiency and even collapse of the biological treatment system.

[0050] Example 1: The inoculated sludge in this example was taken from the secondary sedimentation tank of a sewage treatment plant in Nanjing City, and the sludge concentration was about 4100 mg / L. The sludge was divided into two groups A and B, and the treatment mode was continuous flow. The influent was artificially prepared and contained about 300 mg / L of COD, 50 mg / L of NH4 + -N 10 mg / L of total phosphorus, pH 7.5-7.8, water temperature was normal temperature (20-25℃), hydraulic retention time was 12 h. The influent of group A was also added with 5 mg / L of ibuprofen (to indicate that the device can also operate normally under high concentration of ibuprofen interference). The initial dissolved oxygen concentration of the two groups of sludge was 4.0 mg / L, which was reduced by 0.5 mg / L every 7 days, and the effluent quality was detected every day and the average treatment effect in seven days was calculated.

[0051] The experimental results are shown in Figure 2 (COD removal rate) and Figure 3 (ammonia nitrogen removal rate), it is found that when the influent does not contain ibuprofen, the removal efficiency of pollutants does not decrease basically when the dissolved oxygen is reduced to 1.0 mg / L, and the aerobic activated sludge system cannot maintain stability until the dissolved oxygen is reduced to 0.5 mg / L, and the effluent quality is greatly deteriorated; when the influent contains 5 mg / L of ibuprofen, the ammonia nitrogen removal effect is obviously decreased when the dissolved oxygen is lower than 2.5 mg / L, and the COD removal efficiency is also obviously inhibited when the dissolved oxygen reaches 1.0 mg / L. The experiment proves that the minimum dissolved oxygen of low-oxygen activated sludge method can be controlled at 1.0-1.5 mg / L, and when the influent contains 5 mg / L of ibuprofen, the dissolved oxygen is lower than 2.5 mg / L, which will cause the system to greatly decrease the pollutant removal capacity.

[0052] Example 2: The inoculated sludge in this example was taken from the secondary sedimentation tank of a sewage treatment plant in Nanjing City, and the sludge concentration was about 3300 mg / L. The influent was artificially prepared and contained about 300 mg / L of COD, 50 mg / L of NH4 + -N 10 mg / L of total phosphorus, pH 7.5-7.8, water temperature was normal temperature (20-25℃), hydraulic retention time was 12 h, and the dissolved oxygen was maintained at 1.5 mg / L. The sludge was divided into 9 groups, and the ibuprofen concentration in the influent was 0 μg / L, 20 μg / L, 50 μg / L, 100 μg / L, 200 μg / L, 500 μg / L, 1000 μg / L, 2000 μg / L, and 5000 μg / L, respectively. The effluent quality was detected continuously for seven days, and the average treatment effect was calculated.

[0053] The experimental results are shown in Figure 4As shown in the figure, it can be found that the concentration of ibuprofen has little effect on the COD removal effect, that is, even if the concentration reaches 5000 μg / L, the sludge removal effect on COD still remains above 90%, but when the concentration of ibuprofen reaches 100 μg / L, the sludge removal effect on ammonia nitrogen is inhibited.

[0054] Example 3: In this example, the inoculated sludge is taken from the secondary sedimentation tank of a sewage treatment plant in Nanjing, the sludge concentration in the variable oxygen aeration tank is 2900 mg / L, the dissolved oxygen is controlled at 2.5 mg / L, and the hydraulic retention time is 12 h; the sludge concentration in the low-oxygen aeration tank is 6700 mg / L, the dissolved oxygen is controlled at 1.0 mg / L, and the sludge discharge period is 4 d. The influent is artificial water, containing COD of about 300 mg / L, NH4 + -N 50 mg / L, total phosphorus 10 mg / L, and also containing a certain amount of ibuprofen. The concentration of ibuprofen in the influent is 100 μg / L, 500 μg / L, 2000 μg / L, and 5000 μg / L respectively in the first to third days, the fourth to sixth days, the seventh to ninth days, and the tenth to twelfth days. The effluent water quality and ibuprofen content are detected.

[0055] The experimental results are shown in the figure. Figure 5 During the operation, the sludge properties are stable, there is no sludge bulking phenomenon, the effluent water quality is good, and the ibuprofen removal effect also reaches about 80%.

[0056] The details not described in the present application are the known technology of those skilled in the art.

[0057] Finally, it should be noted that: the above specific embodiments are only used to illustrate the technical solutions of the present application and not to limit, although the present application is described in detail with reference to the examples, those skilled in the art should understand that the technical solutions of the present application can be modified and replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application, which should be covered in the scope of the claims of the present application.

Claims

1. A method of treating ibuprofen-containing wastewater, characterized by, The device for treating wastewater containing ibuprofen comprises: a low-oxygen aeration tank and a variable-oxygen aeration tank, and two sedimentation tanks connected in series with the low-oxygen aeration tank and the variable-oxygen aeration tank respectively; two adjustable air pumps, one for each of the low-oxygen aeration tank and the variable-oxygen aeration tank, for aeration; two dissolved oxygen control devices, one for each of the adjustable air pumps, for monitoring the dissolved oxygen concentration in the low-oxygen aeration tank and the variable-oxygen aeration tank and adjusting the dissolved oxygen concentration in the two aeration tanks; the low-oxygen aeration tank and the variable-oxygen aeration tank are connected in series through a sludge conveying pipe, the low-oxygen aeration tank further comprises a low-oxygen aeration tank water inlet pipe, and the variable-oxygen aeration tank further comprises a variable-oxygen aeration tank water inlet pipe; the method comprises the following steps: S1: when no ibuprofen is detected in the influent or the ibuprofen concentration does not reach a certain threshold value, the device is in a non-response state, the valve of the sludge conveying pipe is closed, the water inlets of the low-oxygen aeration tank and the variable-oxygen aeration tank are opened, and after a certain period of time, the treated sludge-water mixture is discharged into the two sedimentation tanks through the first and second sludge collection pipes, and part of the settled sludge in the sedimentation tanks is returned to the two aeration tanks through the first and second sludge return pipes; S2: when a certain concentration of ibuprofen is detected in the influent, the device enters a response state, the water inlet of the low-oxygen aeration tank and the valve of the first sludge collection pipe are closed, the valve of the sludge conveying pipe is opened, the sludge in the low-oxygen aeration tank is in a starved state, the starved sludge in the low-oxygen aeration tank is conveyed to the variable-oxygen aeration tank through the sludge conveying pipe, and the wastewater containing ibuprofen is mixed with the starved sludge in the variable-oxygen aeration tank through the water inlet pipe, after a period of time, the treated sludge-water mixture is discharged into the sedimentation tank through the second sludge collection pipe, and part of the settled sludge is returned to the low-oxygen aeration tank through the first sludge return pipe; in step S1, the sludge concentration in the low-oxygen aeration tank and the variable-oxygen aeration tank is between 4000 and 6000 mg / L, and the dissolved oxygen in the low-oxygen aeration tank and the variable-oxygen aeration tank is between 1.0 and 1.5 mg / L; in step S2, the sludge concentration in the low-oxygen aeration tank is between 5000 and 10000 mg / L, the sludge concentration in the variable-oxygen aeration tank is between 2000 and 4000 mg / L, the dissolved oxygen in the low-oxygen aeration tank is between 1.0 and 1.5 mg / L, and the dissolved oxygen in the variable-oxygen aeration tank is 3.0±0.5 mg / L.

2. The method of treating ibuprofen-containing wastewater according to claim 1, wherein, in step S1, the hydraulic retention time of the low-oxygen aeration tank and the variable-oxygen aeration tank is 10-12 h.

3. The method of treating ibuprofen-containing wastewater according to claim 1, wherein in step S2, the hydraulic retention time of the variable-oxygen aeration tank is 12-15 h, and the sludge retention time of the low-oxygen aeration tank is 3-5 days, i.e. 1 / 5-1 / 3 of the sludge is inoculated into the variable-oxygen aeration tank through the sludge conveying pipe every day, and the corresponding sludge is supplemented from the low-oxygen aeration tank to maintain the amount of sludge in the variable-oxygen aeration tank unchanged.

4. The method of treating ibuprofen-containing wastewater according to claim 1, wherein in step S1, the threshold value is 100 μg / L, and in step S2, the lower limit of the ibuprofen concentration in the influent is 100 μg / L.

5. The method of treating ibuprofen-containing wastewater according to claim 1, wherein Each of the dissolved oxygen control devices comprises a dissolved oxygen probe located in the variable oxygen aeration tank for monitoring and feeding back to adjust the dissolved oxygen of the aeration tank, and a controller connected with the adjustable air pump to control the aeration amount of the adjustable air pump.

6. The method of treating ibuprofen-containing wastewater according to claim 1, wherein The secondary sedimentation tank comprises a sludge discharge pipe and a water discharge pipe; the secondary sedimentation tank and the low-oxygen aeration tank are connected in series through a first sludge collection pipe and a first sludge return pipe, and the secondary sedimentation tank and the variable oxygen aeration tank are connected in series through a second sludge collection pipe and a second sludge return pipe.

7. The method of treating ibuprofen-containing wastewater according to claim 1, wherein The sludge age of the low-oxygen aeration tank and the variable oxygen aeration tank is 20 d.

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