A device and method for treating oxytetracycline production wastewater by heterotrophic-autotrophic simultaneous reinforcement and synergistic denitrification

Abstract

The application provides a terramycin production wastewater treatment device and method for heterotrophic-autotrophic synchronous reinforcement and collaborative denitrification. The device comprises an anaerobic tank, an aerobic tank, an anoxic tank and a sedimentation tank arranged in sequence; the modified zeolite and anaerobic ammonia oxidation bacteria biofilm are arranged in the anoxic tank; the anaerobic digestion effluent enters the anaerobic tank for heterotrophic denitrification; the anaerobic tank effluent enters the aerobic tank after coagulation by polymeric ferric sulfate, short-term nitrification is carried out in the aerobic tank by gap aeration; the anaerobic ammonia oxidation autotrophic denitrification reaction is carried out in the anoxic tank; the nitrate-containing effluent in the anoxic tank is backflowed to the anaerobic tank to realize deep denitrification of the wastewater; the anoxic tank effluent enters the sedimentation tank, and the sludge in the sedimentation tank is backflowed to the aerobic tank to maintain the amount of autotrophic denitrification microorganisms. The application strengthens the heterotrophic and autotrophic denitrification paths step by step, collaboratively improves the denitrification efficiency, solves the problems of carbon source dependence, refractory organic matter and antibiotic inhibition in the traditional process, and high sludge yield, and is suitable for high-concentration terramycin pharmaceutical wastewater treatment.

Description

Technical Field

[0001] The present invention relates to the technical field of pharmaceutical wastewater treatment, and specifically to an oxytetracycline production wastewater treatment device and method for synchronous enhancement and synergistic denitrification of heterotrophic and autotrophic processes. Background Art

[0002] Oxytetracycline is a commonly used broad-spectrum antibiotic, and high-concentration organic pollutants and high-nitrogen-content wastewater are generated during its pharmaceutical production process. Such wastewater is characterized by high-difficulty biodegradable COD, high ammonia nitrogen, and complex components. Current treatment methods mainly include physicochemical methods and biological methods. Although physicochemical methods (such as adsorption, advanced oxidation, etc.) can partially remove pollutants, they have high treatment costs and secondary pollution problems. Compared with physicochemical methods, biological methods have the advantages of low treatment cost and environmental friendliness. Therefore, biological methods are more widely used.

[0003] In the existing oxytetracycline wastewater treatment process, polyferric sulfate is usually added after the effluent of the biochemical system for deep treatment to remove residual refractory organic matter and ensure that the effluent quality meets the standards. However, the high content of refractory organic matter (especially substances such as antibiotics) in the influent will significantly inhibit the biochemical system, greatly reducing the biological denitrification efficiency. In addition, the ammonia nitrogen concentration in oxytetracycline production wastewater can reach hundreds of mg / L, the content of refractory organic matter in the water is high, and the easily biodegradable carbon source is insufficient, resulting in incomplete denitrification and difficulty in stably meeting the standards. Therefore, how to optimize the pretreatment of refractory organic matter to weaken the inhibition of microorganisms and how to strengthen the contribution of autotrophic denitrification such as anaerobic ammonium oxidation have become the upgrade routes for efficient treatment of oxytetracycline wastewater. Summary of the Invention

[0004] The purpose of the present invention is to provide an oxytetracycline production wastewater treatment device and method for synchronous enhancement and synergistic denitrification of heterotrophic and autotrophic processes, so as to solve the problems in the prior art such as incomplete removal of refractory organic matter, obvious biochemical inhibition effect, and easy total nitrogen exceeding the standard, thereby achieving efficient, low-consumption, and deep denitrification of wastewater, reducing the operation cost, and strengthening the stable effluent compliance.

[0005] The present invention is achieved as follows:

[0006] An oxytetracycline production wastewater treatment device for synchronous enhancement of heterotrophic-autotrophic and collaborative denitrification, comprising an anaerobic tank, an aerobic tank, an anoxic tank and a sedimentation tank arranged in sequence; intermittent aeration is provided in the aerobic tank, and modified zeolite and anammox bacteria biofilm are provided in the anoxic tank; anaerobic digestion effluent enters the anaerobic tank, and heterotrophic denitrification is carried out in the anaerobic tank; the effluent from the anaerobic tank enters the aerobic tank after coagulation with polyferric sulfate, and short-term nitrification reaction is carried out in the aerobic tank; the effluent from the aerobic tank enters the anoxic tank, and anammox autotrophic denitrification reaction is carried out in the anoxic tank; the nitrate-containing effluent in the anoxic tank is refluxed to the anaerobic tank to achieve deep sewage denitrification; the effluent from the anoxic tank enters the sedimentation tank, and the sludge in the sedimentation tank is refluxed to the aerobic tank to maintain the amount of autotrophic denitrifying microorganisms.

[0007] Preferably, the anoxic tank is formed by stopping aeration at the end of the original aerobic tank, and the front end of the original aerobic tank constitutes the aerobic tank; the anoxic tank accounts for 10% - 30% of the volume of the original aerobic tank.

[0008] Preferably, when intermittent aeration is carried out in the aerobic tank, the ratio of aeration time to non-aeration time is 2:1.

[0009] Preferably, the modified zeolite is specifically: zeolite modified with 0.8 mol / L sodium chloride and having a particle size of 0.5 - 1.0 mm.

[0010] Preferably, the dosage of the modified zeolite is 200 g / L. [[ID= =13]]

[0011] The oxytetracycline production wastewater treatment method for synchronous enhancement of heterotrophic-autotrophic and collaborative denitrification provided by the present invention adopts the above device, and specifically includes the following steps:

[0012] (1) Anaerobic digestion effluent enters the anaerobic tank, and heterotrophic denitrification is carried out in the anaerobic tank;

[0013] (2) Polyferric sulfate is added to the effluent from the anaerobic tank for coagulation to remove suspended solids and refractory organic matter in the wastewater;

[0014] (3) The wastewater after the coagulation effect of polyferric sulfate enters the aerobic tank, and intermittent aeration is carried out in the aerobic tank;

[0015] (4) The effluent from the aerobic tank undergoes autotrophic denitrification in the anoxic tank through the modified zeolite and anammox bacteria biofilm;

[0016] (5) The nitrate-containing effluent in the anoxic tank is refluxed to the anaerobic tank to achieve deep sewage denitrification;

[0017] (6) The effluent from the anoxic tank enters the sedimentation tank, and the sludge in the sedimentation tank is refluxed to the aerobic tank to maintain the amount of autotrophic denitrifying microorganisms.

[0018] Preferably, in step (2), the dosage of polyferric sulfate is 5 - 10‰ of the effluent volume from the anaerobic tank

[0019] Preferably, in step (2), the hydraulic retention time of the anaerobic tank is 8 - 12 h.

[0020] Preferably, in step (3), the ratio of the aeration time to the non-aeration time in the aerobic tank is 2:1, the dissolved oxygen for aeration is controlled at 0.5 - 1.5 mg / L, and the hydraulic retention time is 2 - 5 h.

[0021] Preferably, in step (4), the modified zeolite is specifically zeolite modified with 0.8 mol / L sodium chloride and having a particle size of 0.5 - 1.0 mm; the dosage of the modified zeolite is 200 g / L.

[0022] The present invention relates to an oxytetracycline production wastewater treatment device and method for heterotrophic-autotrophic synchronous strengthening and cooperative denitrification, aiming to strengthen the original heterotrophic denitrification ability, cultivate autotrophic denitrifying microorganisms, reduce the toxicity inhibition effect of autotrophic denitrifying microorganisms, and increase the contribution ratio of autotrophic denitrification, so as to achieve low-cost deep sewage denitrification.

[0023] The present invention has the following beneficial effects:

[0024] 1. Strengthen the original heterotrophic denitrification ability: By adjusting the dosing position of the polyferric sulfate flocculant from the end effluent to the effluent of the anaerobic tank (A tank) and extending the hydraulic retention time (HRT) of the anaerobic zone, the particulate and refractory organic matters in the anaerobic effluent can be fully utilized, the heterotrophic denitrification efficiency can be improved, and the dosing of easily degradable carbon sources can be saved.

[0025] 2. Increase the contribution ratio of autotrophic denitrification: By reconstructing the original aerobic tank (O tank), stopping the aeration at the end of the O tank and changing it into an anoxic tank, and adding a specific modified zeolite carrier to cultivate anaerobic ammonium oxidation bacteria autotrophic denitrifying microorganisms, the contribution ratio of autotrophic denitrification can be increased. The effluent of the O tank contains nitrates and is refluxed to the A tank to achieve deep sewage denitrification.

[0026] 3. Reduce the toxicity inhibition of autotrophic microorganisms: By adjusting the dosing position of the polyferric sulfate flocculant to ensure solid-liquid separation before entering the O tank, the toxicity inhibition effect of suspended solids and refractory organic matters in the sewage on autotrophic microorganisms such as nitrifying bacteria and anaerobic ammonium oxidation bacteria can be reduced, the autotrophic denitrification efficiency can be greatly improved, the operation cost can be reduced, and the effluent can meet the standards stably.

[0027] The device of the present invention provides a new efficient, energy-saving and environmentally friendly way for the low-cost and deep denitrification treatment of oxytetracycline pharmaceutical wastewater, and has broad application prospects. Brief Description of the Drawings

[0028] Figure 1 It is a schematic structural diagram of the oxytetracycline production wastewater treatment device for heterotrophic-autotrophic synchronous strengthening and cooperative denitrification of the present invention.

[0029] Figure 2 It is the flow chart of the treatment method for oxytetracycline production wastewater with heterotrophic-autotrophic synchronous enhancement and cooperative denitrification in the present invention.

[0030] Figure 3 It is the relationship diagram between the particle size of natural zeolite and the ammonia nitrogen adsorption rate.

[0031] Figure 4 It is the relationship diagram between the dosage of natural zeolite and the ammonia nitrogen adsorption rate.

[0032] Figure 5 It is the ammonia nitrogen adsorption diagram of natural zeolite modified by hydrochloric acid, sulfuric acid or nitric acid solutions with different concentrations in wastewater.

[0033] Figure 6 It is the ammonia nitrogen adsorption diagram of natural zeolite modified by sodium hydroxide and potassium hydroxide solutions with different concentrations in wastewater.

[0034] Figure 7 It is the ammonia nitrogen adsorption diagram of natural zeolite modified by sodium chloride, calcium chloride and potassium chloride solutions with different concentrations in wastewater. Specific implementation manners

[0035] The structural schematic diagram of the treatment device for oxytetracycline production wastewater with heterotrophic-autotrophic synchronous enhancement and cooperative denitrification provided by the present invention is as Figure 1 shown. Its structure sequentially includes an anaerobic tank (A tank), an aerobic tank (O tank), an anoxic tank and a sedimentation tank. In the present invention Figure 1 shown in the structural schematic diagram of the device, it is a modification on the original actual tank body. The anaerobic tank and the aerobic tank are independently connected in series, and the end of the aerobic tank is in-situ transformed into an anoxic tank through engineering to realize autotrophic denitrification reaction.

[0036] Combined with Figure 1 and Figure 2 , in the present invention, the anaerobic digestion effluent does not need to be first dosed with polyferric sulfate for solid-liquid separation, but directly enters the anaerobic tank. The hydraulic retention time of the anaerobic tank is 8 - 12 h. In the anaerobic tank, the particulate and refractory organic matters in the water body are fully utilized to strengthen the original heterotrophic denitrification ability.

[0037] Polyferric sulfate is dosed into the effluent of the anaerobic tank, and the dosage is 5 - 10‰ of the effluent volume of the anaerobic tank. Through the coagulation of polyferric sulfate, the suspended solids, refractory COD, particulate matters and chromaticity in the wastewater are removed, and the toxicity inhibition on autotrophic denitrifying microorganisms is reduced, creating good conditions for subsequent autotrophic denitrification.

[0038] Traditional treatment involves solid-liquid separation of anaerobic digestion effluent, consuming a large amount of organic matter, resulting in waste of existing carbon sources. Subsequently, easily degradable carbon sources still need to be added, and excessive chemical sludge is generated, significantly increasing the operating cost. In contrast, the present invention proposes adding polyferric sulfate to the anaerobic pond effluent. On the one hand, it can promote the hydrolysis of particulate and refractory organic matter in the anaerobic pond, strengthen the heterotrophic denitrification nitrogen removal ability of the anaerobic pond, and reduce the dosage of coagulant; on the other hand, it can effectively reduce the toxicity inhibition of particulate and refractory organic matter on autotrophic nitrogen removal microorganisms in the subsequent aerobic pond and anoxic pond, thereby improving the autotrophic nitrogen removal efficiency.

[0039] The wastewater after the coagulation of polyferric sulfate enters the aerobic pond. In the aerobic pond, a low-oxygen intermittent aeration method is adopted, with the ratio of aeration time to non-aeration time being 2:1, the aeration dissolved oxygen controlled at 0.5 - 1.5 mg / L, and the hydraulic retention time being 2 - 5 h. First, a shortcut nitrification reaction is achieved, oxidizing part of the ammonia nitrogen to nitrite, creating conditions for the anaerobic ammonium oxidation denitrification reaction in the subsequent anoxic pond.

[0040] In the present invention, the anoxic pond is formed by stopping aeration in approximately 10% - 30% of the area at the end of the original aerobic pond, that is, upgrading and transforming the end of the aerobic pond in situ into an anoxic pond. Specific modified zeolite fillers are added to the anoxic pond, loading anaerobic ammonium oxidation bacteria (AMX) biofilms for anaerobic ammonium oxidation autotrophic nitrogen removal reaction (denitrification load ≥ 0.5 kg N / (m 3 ·d)). The residue of the polyferric sulfate added to the anaerobic pond effluent will also promote the reaction of the anaerobic ammonium oxidation bacteria biofilm in the anoxic pond, promoting autotrophic nitrogen removal.

[0041] The nitrate-containing effluent from the anoxic pond is refluxed to the front-end anaerobic pond to achieve deep sewage denitrification; the sedimentation tank sludge is refluxed to the aerobic pond to maintain the amount of autotrophic nitrogen removal microorganisms.

[0042] The present invention solves the problems of carbon source dependence, inhibition by refractory organic matter and antibiotics, and high sludge production in traditional processes by stepwise strengthening the heterotrophic and autotrophic nitrogen removal paths and synergistically improving the nitrogen removal efficiency, and is applicable to the treatment of high-concentration pharmaceutical wastewater.

[0043] In the present invention, modified zeolite is selected in the anoxic pond and combined with anaerobic ammonium oxidation for autotrophic nitrogen removal.

[0044] In terms of zeolite selection, considerations are made from several aspects such as zeolite particle size, zeolite addition amount, and zeolite modification method, which are described separately below.

[0045] Regarding the consideration of the particle size of zeolite, in this invention, four portions of 10 g of natural zeolite with particle sizes of 0.5 - 1 mm, 1 - 2 mm, 2 - 3 mm, and 3 - 5 mm were weighed respectively, and each was added to 100 mL of ammonia nitrogen solution with a concentration of about 40 - 50 mg / L. Stirring was carried out at a stirring speed of 150 r / min for 2 h. After filtration, the ammonia nitrogen concentration in the solution after adsorption was measured, and the ammonia nitrogen adsorption rate was calculated. The relationship between the particle size of natural zeolite and the ammonia nitrogen adsorption rate is as Figure 3 shown.

[0046] As Figure 3 can be seen, as the particle size of natural zeolite increases, the ammonia nitrogen adsorption rate gradually decreases from 46.9% to 25.6%, indicating that the ammonia nitrogen concentration in the filtrate gradually decreases, and the ability of zeolite to remove ammonia nitrogen from sewage gradually increases. When the particle size of zeolite changes from 0.5 - 1 mm to 1 - 2 mm, the ammonia nitrogen adsorption rate decreases by 4.8%. When it changes from 1 - 2 mm to 2 - 3 mm, the ammonia nitrogen adsorption rate decreases by 9.3%. This shows that as the particle size increases, the adsorption effect of zeolite on ammonia nitrogen first decreases slowly and then decreases more significantly. Therefore, this invention uses natural zeolite with a particle size of 0.5 - 1 mm.

[0047] Regarding the consideration of the addition amount of zeolite, seven portions of 5 g, 10 g, 15 g, 20 g, 25 g, 30 g, and 35 g of natural zeolite with a particle size of 1 - 2 mm were weighed respectively, and each was added to 100 mL of ammonia nitrogen solution with a concentration of about 40 - 50 mg / L. Stirring was carried out at a stirring speed of 150 r / min for 2 h. After filtration, the ammonia nitrogen concentration in the solution after adsorption was measured, and the ammonia nitrogen adsorption rate was calculated. The relationship between the dosage of natural zeolite and the ammonia nitrogen adsorption rate is as Figure 4 shown.

[0048] As Figure 4 can be seen, as the addition amount of zeolite increases, the ammonia nitrogen adsorption rate gradually increases from 31.5% to 47.2%. When the addition amount of zeolite is less than 20 g, the ammonia nitrogen adsorption rate increases with the increase of the addition amount of zeolite. When the addition amount of zeolite is greater than 20 g, the ammonia nitrogen adsorption rate is in the range of 45.9% - 47.2%, and the change is not obvious with the increase of the addition amount of zeolite. This indicates that the mass of ammonia nitrogen adsorbed per unit mass of zeolite decreases with the increase of the addition amount of zeolite, and there are differences in the adsorption amount of ammonia nitrogen with different zeolite dosages. The reason for the analysis is that with the increase of the addition amount of zeolite in ammonia nitrogen wastewater with a certain concentration, the attachment sites provided by per unit mass of zeolite for ammonia nitrogen ions decrease. Considering the comprehensive economic cost, this invention selects the addition amount of zeolite as 20 g / 100 mL.

[0049] Regarding the consideration of the modification method of zeolite, in this invention, the effects of inorganic acid, inorganic base, and inorganic salt on the ammonia nitrogen adsorption rate after modifying natural zeolite were studied respectively.

[0050] The adsorption of ammonia nitrogen in wastewater by natural zeolite modified with hydrochloric acid, sulfuric acid or nitric acid solutions of different concentrations is as Figure 5 shown.

[0051] As Figure 5 can be seen, the change range of ammonia nitrogen adsorption rate of hydrochloric acid modified zeolite is 36.7% - 54.7%, the change range of ammonia nitrogen adsorption rate of sulfuric acid modified zeolite is 23.8% - 35.0%, and the change range of ammonia nitrogen adsorption rate of nitric acid modified zeolite is 19.0% - 30.8%. The ammonia nitrogen adsorption rate of hydrochloric acid modified zeolite is significantly greater than that of sulfuric acid modified zeolite, followed by nitric acid modified zeolite. When the hydrochloric acid concentration of hydrochloric acid modified zeolite is between 0.1mol / L and 0.5mol / L, its ammonia nitrogen adsorption rate is slightly greater than that of natural zeolite, and it is lower than that of natural zeolite at other concentrations. It can be seen that after being modified with three different concentrations of inorganic acids, the ammonia nitrogen adsorption rate of zeolite in wastewater has not increased significantly, but there is a decreasing trend. The reason is that low-concentration inorganic acids can dissolve some impurities in the pores and channels of zeolite, which can slightly increase the ammonia nitrogen adsorption capacity of zeolite; however, with the increase of acid concentration, the microporous structure of zeolite is damaged, resulting in a decrease in ammonia nitrogen adsorption rate.

[0052] The adsorption of ammonia nitrogen in wastewater by natural zeolite modified with sodium hydroxide and potassium hydroxide solutions of different concentrations is as Figure 6 shown.

[0053] As Figure 6 can be seen, the change range of ammonia nitrogen adsorption rate of sodium hydroxide modified zeolite is 42.0% - 68.5%, the change range of ammonia nitrogen adsorption rate of potassium hydroxide modified zeolite is 40.3% - 60.8%, and the ammonia nitrogen adsorption rate of sodium hydroxide modified zeolite is significantly greater than that of potassium hydroxide modified zeolite. When the concentration of inorganic base is greater than 0.2mol / L, the ammonia nitrogen adsorption rate of sodium hydroxide and potassium hydroxide modified zeolite is greater than that of natural zeolite. It can be seen that after being modified with two different concentrations of inorganic bases, the ammonia nitrogen adsorption rate of zeolite in wastewater has been significantly improved. When the inorganic base concentration is between 0.8mol / L and 1mol / L, the ammonia nitrogen adsorption rate decreases. The reason is that low-concentration inorganic bases reduce the silicon-aluminum ratio of zeolite, improve the relevant ion exchange performance, and sodium ions or potassium ions are introduced into the zeolite pores, which is beneficial to the adsorption of ammonia nitrogen by zeolite, while high-concentration inorganic bases will cause certain damage to the original internal structure of zeolite, change its microporous adsorption state, and reduce the ammonia nitrogen adsorption rate to a certain extent.

[0054] The adsorption of ammonia nitrogen in wastewater by natural zeolite modified with sodium chloride, calcium chloride and potassium chloride solutions of different concentrations is as Figure 7 shown.

[0055] As Figure 7It can be seen that the ammonia nitrogen adsorption rate of sodium chloride modified zeolite ranges from 58.0% to 78.2%, the ammonia nitrogen adsorption rate of calcium chloride modified zeolite ranges from 48.0% to 59.7%, and the ammonia nitrogen adsorption rate of potassium chloride modified zeolite ranges from 51.3% to 70.8%. When the sodium chloride concentration is between 0.1 mol / L and 0.8 mol / L, the ammonia nitrogen adsorption rate of the modified zeolite increases from 58% to the highest 78.2%. When the sodium chloride concentration is between 0.8 mol / L and 2 mol / L, the ammonia nitrogen adsorption rate of the modified zeolite gradually decreases from 78.2% to 62.7%. When the potassium chloride concentration is between 0.1 mol / L and 0.7 mol / L, the ammonia nitrogen adsorption rate of the modified zeolite increases from 51.0% to the highest 70.8%. When the potassium chloride concentration is between 0.7 mol / L and 2 mol / L, the ammonia nitrogen adsorption rate of the modified zeolite slowly decreases from 70.8% to 52.5%. When the calcium chloride concentration is between 0.1 mol / L and 0.4 mol / L, the ammonia nitrogen adsorption rate of the modified zeolite increases from 48.0% to the highest 59.7%. When the calcium chloride concentration is between 0.4 mol / L and 0.75 mol / L, the ammonia nitrogen adsorption rate of the modified zeolite decreases from 59.7% to the ammonia nitrogen adsorption rate level of natural zeolite, which is 47.5%. When the calcium chloride concentration is greater than 0.75 mol / L, the ammonia nitrogen adsorption rate of the modified zeolite is lower than that of natural zeolite. It can be seen that after modification with three different inorganic salts, the ammonia nitrogen adsorption rate of zeolite has a significant increase except for calcium chloride.

[0056] As can be seen above, among the three inorganic salt modified zeolites, the sodium chloride modified zeolite has the best ammonia nitrogen adsorption effect, followed by the potassium chloride modified zeolite, and the calcium chloride modified zeolite has the worst adsorption effect. This modification method can significantly improve the ammonia nitrogen adsorption capacity of zeolite. The reason is that sodium ions exchange some of the original calcium ions in the zeolite and act as a role in balancing the negative charges on the silicon oxygen tetrahedron. The interaction between these low-valence and large-radius ions and the structural units is weak, so they can be peeled off under the action of interlayer solvent and dispersed into thinner single crystal wafers, which also makes the zeolite have a larger internal surface area. This large specific surface area with charges provides a strong dispersion force, making it a highly adsorbent sodium-type zeolite, thus enhancing the ammonia nitrogen adsorption capacity of natural zeolite.

[0057] Therefore, in the anoxic tank, the selected zeolite is the zeolite modified with 0.8 mol / L sodium chloride and with a particle size of 0.5 - 1.0 mm, and the dosing weight of the zeolite is 200 g / L, which is more suitable for the actual wastewater from oxytetracycline production targeted by the present invention.

[0058] The oxytetracycline production wastewater is treated by the process of the present invention, and the specific experimental data are as follows: the COD concentration of the anaerobic digestion effluent is 3000 mg / L, and the ammonia nitrogen concentration is 400 mg N / L. After treatment in the anaerobic tank, the COD concentration of the effluent is 1000 mg / L, and the ammonia nitrogen concentration is 150 mg N / L; after adding polyferric sulfate, the COD concentration is 200-400 mg / L, and the removal rate of refractory organic matter is 60-80%; the ammonia nitrogen concentration in the aerobic tank is 60 mg N / L, and the nitrite nitrogen concentration is 60 mg N / L, and the aeration energy consumption can be reduced by 40%. Anaerobic ammonium oxidation reaction occurs in the anoxic tank at the end of the aerobic tank, the total nitrogen concentration of the effluent is less than 20 mg / L, the contribution rate of autotrophic denitrification is higher than 20%, and the overall operation cost is reduced by about 30%.

Claims

1. A device for treating oxytetracycline production wastewater with simultaneous heterotrophic-autotrophic enhancement and synergistic denitrification, characterized in that, The system includes an anaerobic tank, an aerobic tank, an anoxic tank, and a sedimentation tank arranged in sequence. The aerobic tank is equipped with intermittent aeration, while the anoxic tank contains modified zeolite and an anaerobic ammonia-oxidizing bacteria biofilm. Anaerobic digestion effluent enters the anaerobic tank for heterotrophic denitrification. The effluent from the anaerobic tank is coagulated with polyferric sulfate and then enters the aerobic tank for short-cut nitrification. The effluent from the aerobic tank enters the anoxic tank for anaerobic ammonia oxidation autotrophic denitrification. Nitrate-containing effluent from the anoxic tank is returned to the anaerobic tank for deep denitrification. The effluent from the anoxic tank enters the sedimentation tank, and the sludge from the sedimentation tank is returned to the aerobic tank to maintain the autotrophic denitrification microbial biomass.

2. The oxytetracycline production wastewater treatment device with simultaneous heterotrophic-autotrophic enhancement and synergistic denitrification as described in claim 1, characterized in that, The anoxic tank is formed by stopping aeration at the end of the original aerobic tank, and the front end of the original aerobic tank constitutes the aerobic tank; the anoxic tank occupies 10% to 30% of the volume of the original aerobic tank.

3. The oxytetracycline production wastewater treatment device with simultaneous heterotrophic-autotrophic enhancement and synergistic denitrification as described in claim 1, characterized in that, When intermittent aeration is used in the aerobic tank, the ratio of aeration time to non-aeration time is 2:

1.

4. The oxytetracycline production wastewater treatment device with simultaneous heterotrophic-autotrophic enhancement and synergistic denitrification as described in claim 1, characterized in that, The modified zeolite is specifically: zeolite modified with 0.8 mol / L sodium chloride, with a particle size of 0.5~1.0 mm.

5. The oxytetracycline production wastewater treatment device with simultaneous enhanced heterotrophic-autotrophic and synergistic denitrification as described in claim 1, characterized in that, The dosage of modified zeolite is 200 g / L.

6. A method for treating oxytetracycline production wastewater with simultaneous heterotrophic-autotrophic enhancement and synergistic denitrification, characterized in that, The method employs the apparatus of claim 1 and includes the following steps: (1) Anaerobic digestion effluent enters the anaerobic tank, where heterotrophic denitrification is carried out; (2) Add polyferric sulfate to the effluent from the anaerobic tank for coagulation to remove suspended solids and recalcitrant organic matter from the wastewater; (3) The wastewater after coagulation by polyferric sulfate enters the aerobic tank and is intermittently aerated in the aerobic tank; (4) The effluent from the aerobic tank undergoes autotrophic denitrification in the anoxic tank by passing a modified zeolite-loaded anaerobic ammonia oxidation biofilm; (5) The nitrate-containing effluent from the anoxic tank is returned to the anaerobic tank to achieve deep denitrification of the wastewater; (6) The effluent from the anoxic tank enters the sedimentation tank, and the sludge in the sedimentation tank is returned to the aerobic tank to maintain the amount of autotrophic denitrifying microorganisms.

7. The method for treating oxytetracycline production wastewater with simultaneous enhanced heterotrophic-autotrophic and synergistic denitrification according to claim 6, characterized in that, In step (2), the amount of polyferric sulfate added is 5-10‰ of the effluent from the anaerobic tank.

8. The method for treating oxytetracycline production wastewater with simultaneous enhanced heterotrophic-autotrophic and synergistic denitrification according to claim 6, characterized in that, In step (2), the hydraulic retention time in the anaerobic tank is 8~12 h.

9. The method for treating oxytetracycline production wastewater with simultaneous enhanced heterotrophic-autotrophic and synergistic denitrification according to claim 6, characterized in that, In step (3), the ratio of aeration time to non-aeration time in the aerobic tank is 2:1, the dissolved oxygen during aeration is controlled at 0.5~1.5 mg / L, and the hydraulic retention time is 2~5 h.

10. The method for treating oxytetracycline production wastewater with simultaneous enhanced heterotrophic-autotrophic and synergistic denitrification according to claim 6, characterized in that, In step (4), the modified zeolite is specifically zeolite modified with 0.8 mol / L sodium chloride and with a particle size of 0.5~1.0 mm; the dosage of modified zeolite is 200 g / L.

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