Pharmaceutical wastewater treatment method

Abstract

The invention discloses a pharmaceutical wastewater treatment method, and relates to the field of wastewater treatment. Comprising the following steps: carrying out evaporation salting-out treatment on high-salt pharmaceutical wastewater in advance, adjusting water quality and water quantity of evaporation condensate water and general pharmaceutical wastewater in an adjusting tank, and precipitating in a primary settling tank; the wastewater enters a primary catalytic ozonation tank for oxidation treatment, enters a biochemical treatment procedure, enters a secondary sedimentation tank for sedimentation, and effluent enters a secondary catalytic ozonation tank for oxidation treatment and enters an activated carbon filter tank for treatment. Aiming at the characteristics of high salinity, high ammonia nitrogen concentration and high toxicity of pharmaceutical wastewater, the salt concentration is reduced by adopting evaporation salting-out treatment, and the biodegradability is improved by utilizing oxidation treatment of the first-stage catalytic ozonation pond, so that the subsequent biochemical treatment efficiency is high, and a large amount of organic matters are decomposed; and a secondary ozone catalysis tank and an activated carbon filter tank are subsequently adopted to remove residual pollutants in the wastewater, so that the COD (Chemical Oxygen Demand), ammonia nitrogen, total phosphorus, total nitrogen and suspended matter concentration of effluent are low, and the effluent can stably reach emission indexes.

Description

Technical Field

[0001] The invention relates to the field of wastewater treatment, and in particular to a method for treating pharmaceutical wastewater. Background Art

[0002] The pharmaceutical industry is an important part of the development of the national economy. It is classified into fermentation pharmaceuticals, chemical synthesis pharmaceuticals, extraction pharmaceuticals, traditional Chinese medicine pharmaceuticals, bioengineering pharmaceuticals, etc. according to the type of pharmaceutical process. Among them, the main principle of chemical synthesis pharmaceuticals is to use a series of chemical reactions to generate active pharmaceutical ingredients, to generate fully synthetic and semi-synthetic pharmaceuticals, such as nervous system, anti-microbial infection, respiratory, cardiovascular, hormone, etc. Most of these pharmaceuticals belong to chemical synthesis pharmaceuticals, which account for about 47.2% of the Chinese pharmaceutical market.

[0003] The pharmaceutical industry will produce a variety of pollution, among which water pollution is the most concerned and is one of the ten key industry pollutions specially rectified in the water pollution prevention and control action plan. Chemical synthesis pharmaceuticals have many production process steps, long cycles, and many raw and auxiliary materials. The water pollution produced has complex chemical composition, high organic matter concentration, high salt, high ammonia nitrogen concentration, poor biodegradability of wastewater, and great difficulty in treatment. Due to the complexity and toxicity of chemical synthesis pharmaceutical wastewater, the wastewater is characterized by high COD concentration, poor biodegradability, and the presence of many toxic substances. Traditional biological treatment is difficult to effectively remove pollutants in wastewater. Summary of the invention

[0004] The present invention provides a method for treating pharmaceutical wastewater to solve the technical problems that pharmaceutical wastewater has high COD, high ammonia nitrogen, high salinity, high concentrations of organic matter and toxic substances, resulting in poor biodegradability, low biochemical treatment efficiency, and effluent quality failing to stably meet standards.

[0005] In order to solve the above technical problems, the present invention provides a method for treating pharmaceutical wastewater, comprising the following steps:

[0006] (1) The pharmaceutical wastewater enters the regulating tank for water quality and water quantity adjustment, and the effluent enters the primary sedimentation tank to precipitate suspended particles;

[0007] (2) the effluent from the primary sedimentation tank enters a primary ozone catalytic oxidation tank for oxidation treatment;

[0008] (3) the effluent from the primary ozone catalytic oxidation tank enters a biochemical treatment process, the biochemical treatment process includes a multi-stage anoxic tank and a multi-stage aerobic tank treatment;

[0009] (4) the effluent from the biochemical treatment process enters a secondary sedimentation tank, where the wastewater is precipitated and the mud and water are separated;

[0010] (5) the effluent from the secondary sedimentation tank is fed into a secondary ozone catalytic oxidation tank for oxidation treatment;

[0011] (6) the effluent from the secondary ozone catalytic oxidation tank enters an activated carbon filter for treatment and then enters a clean water tank;

[0012] Wherein, in step (1), the pharmaceutical wastewater includes high-salt pharmaceutical wastewater with a salt concentration higher than 10000 mg / L, high-salt pharmaceutical wastewater with a salt concentration higher than 10000 mg / L, and general pharmaceutical wastewater with a salt concentration lower than or equal to 10000 mg / L, the high-salt pharmaceutical wastewater is preliminarily subjected to evaporation and salt precipitation treatment, and the separated evaporation condensate and general pharmaceutical wastewater enter the regulating tank together, and the salt concentration of the effluent from the regulating tank is adjusted to be less than 4000 mg / L;

[0013] In steps (2) and (5), the primary ozone catalytic oxidation tank and the secondary ozone catalytic oxidation tank use ozone micro-nano bubbles and ultraviolet lamp technology for catalytic oxidation.

[0014] By adopting the above technical scheme, the present application aims at the characteristics of pharmaceutical wastewater with high salt content, high organic matter concentration, low biodegradability, high ammonia nitrogen concentration and high toxicity. Evaporative salting-out treatment is used to crystallize the salt in the wastewater to reduce the salt concentration of the wastewater; oxidation treatment is carried out using ozone micro-nano bubbles and ultraviolet lamp technology, which is beneficial to improving the oxidation efficiency of ozone. Ozone can oxidize toxic substances in the wastewater into non-toxic or slightly toxic substances, and at the same time oxidize and decompose biochemically difficult-to-degrade organic matter into small molecules, thereby improving the biodegradability of the wastewater and the growth and reproduction of aerobic and anaerobic bacteria in the subsequent biochemical treatment process. The biochemical treatment efficiency is improved, and organic matter can be decomposed in large quantities in the biochemical treatment process, thereby reducing the COD and ammonia nitrogen concentrations of the wastewater. The subsequent treatment using a secondary ozone catalytic pool can oxidize the residual difficult-to-decompose organic pollutants in the wastewater, and the activated carbon filter intercepts and filters the suspended matter, odor and chromaticity in the wastewater, so that the COD, ammonia nitrogen, total phosphorus, total nitrogen and suspended matter concentrations of the effluent water quality are all low, and the emission indicators can be stably met.

[0015] As a preferred embodiment, in step (1), the evaporation and salt precipitation temperature of the high-salt pharmaceutical wastewater is 90-100°C.

[0016] As a preferred embodiment, in step (3), the biochemical treatment process includes a primary anoxic tank, a primary aerobic tank, a secondary anoxic tank and a secondary aerobic tank for sequential treatment.

[0017] As a preferred embodiment, in step (3), the primary anoxic tank and the secondary anoxic tank control DO≤0.3 mg / L.

[0018] As a preferred solution, in step (3), the DO of the primary aerobic tank is controlled to be 2-6 mg / L, and the DO of the secondary aerobic tank is controlled to be 3-6 mg / L.

[0019] By adopting the above scheme, in the pharmaceutical wastewater of this application, under the action of anaerobic bacteria in the primary anoxic tank, macromolecular organic matter such as starch, fiber, protein, etc. in the wastewater is hydrolyzed into organic acid, further improving the biodegradability of the wastewater, and at the same time, denitrification reaction is carried out under the action of denitrifying bacteria to reduce the total nitrogen of the wastewater; at the same time, under the action of aerobic bacteria in the primary aerobic tank, the ammonia nitrogen in the water undergoes nitrification reaction under the action of nitrifying bacteria, and the organic pollutants in the water are oxidized and decomposed into CO2 and H2O, completing the large-scale removal of organic matter, and reducing the ammonia nitrogen in the water. After being treated in multiple anoxic tanks and aerobic tanks, the organic matter in the wastewater can be removed in large quantities, and the ammonia nitrogen content is greatly reduced. In the secondary anoxic tank, the microorganisms in the wastewater further reduce nitrates and nitrites to nitrogen gas through reduction, so that the total nitrogen of the effluent is further reduced, and the secondary aerobic tank further degrades the organic matter in the wastewater to improve the effluent water quality.

[0020] As a preferred embodiment, in steps (2) and (5), the primary ozone catalytic oxidation tank and the secondary ozone catalytic oxidation tank are provided with an ozone micro-nano bubble generator and an ultraviolet lamp.

[0021] As a preferred embodiment, in step (2), the ozone dosage of the ozone micro-nano bubble generator is 150-200 mg / L, the treatment time is 1-2 hours, the ultraviolet light wavelength is 185-400 nm, and the intensity is 50-200 mw / cm 2 .

[0022] As a preferred solution, in step (5), the ozone dosage of the ozone micro-nano bubble generator is 15-20 mg / L, the microbubble size is 10-50 μm, the treatment time is 1-2 h, the ultraviolet light wavelength is 185-400 nm, and the intensity is 50-200 mw / cm 2 .

[0023] By adopting the above scheme, in the primary ozone catalytic oxidation tank and the secondary ozone catalytic oxidation tank, the ozone generated by the ozone generator is mixed with the wastewater to produce a high-concentration ozone-microbubble mixed gas-liquid in the microbubble generator, which is aerated in the primary ozone catalytic oxidation tank through a stainless steel aeration head to achieve oxidation treatment of the wastewater. The primary ozone catalytic oxidation tank can improve the biodegradability of the wastewater, and the secondary ozone catalytic oxidation tank can oxidatively degrade the difficult-to-degrade organic matter remaining in the biochemical treatment process, thereby improving the effluent quality.

[0024] As a preferred embodiment, in step (6), the activated carbon in the activated carbon filter tank is a filter layer filler.

[0025] As a preferred embodiment, in step (6), the activated carbon filter is provided with a backwashing system.

[0026] As a preferred embodiment, in step (2), the primary anoxic tank and the secondary anoxic tank are provided with a stirring device.

[0027] As a preferred embodiment, in steps (1) and (4), the sludge produced in the primary sedimentation tank and the secondary sedimentation tank enters the sludge thickening tank, and polyacrylamide is added. The concentrated sludge enters the filter press for dehydration, and the supernatant of the sludge thickening tank and the filtrate produced by the filter press dehydration are refluxed into the regulating tank to regulate the water quantity and water quality.

[0028] As a preferred solution, in step (4), part of the sludge precipitated in the secondary sedimentation tank is returned to the primary anoxic tank and the secondary anoxic tank for sludge replenishment.

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

[0030] 1. In view of the characteristics of pharmaceutical wastewater, such as high salt content, high organic matter concentration, low biodegradability, high ammonia nitrogen concentration and high toxicity, this application adopts evaporative salting-out treatment to separate the salt from the wastewater and crystallize it, thereby reducing the salt concentration of the wastewater. At the same time, a primary ozone catalytic tank is used for oxidation treatment. Ozone can oxidize the toxic substances in the wastewater into non-toxic or slightly toxic substances, and at the same time oxidize and decompose the biochemically difficult-to-degrade organic matter into small molecules, thereby improving the biodegradability of the wastewater, and improving the growth and reproduction of aerobic bacteria and anaerobic bacteria in the subsequent biochemical treatment process, thereby improving the efficiency of the biochemical treatment.

[0031] 2. In the pharmaceutical wastewater of the present application, under the action of anaerobic bacteria in the primary anoxic tank, macromolecular organic matter such as starch, fiber, protein, etc. in the wastewater is hydrolyzed into organic acids, and at the same time, denitrification reaction is carried out under the action of denitrifying bacteria to reduce the total nitrogen in the wastewater; in the primary aerobic tank, ammonia nitrogen in the water undergoes nitrification reaction under the action of nitrifying bacteria, and organic pollutants in the water are oxidized and decomposed into CO2 and H2O, thereby completing the large-scale removal of organic matter and reducing ammonia nitrogen in the water.

[0032] 3. In the secondary anoxic tank of the present application, the microorganisms in the wastewater further reduce nitrate and nitrite into nitrogen gas through reduction, so that the total nitrogen in the effluent is further reduced. The secondary aerobic tank further degrades the organic matter in the wastewater to improve the effluent water quality.

[0033] 4. This application implements a deep treatment system after the biochemical treatment process, and adopts a secondary ozone catalytic tank to treat the residual difficult-to-decompose organic pollutants in the wastewater. At the same time, the activated carbon filter intercepts and filters the suspended matter, odor, and color in the wastewater, so that the COD, ammonia nitrogen, total phosphorus, total nitrogen and suspended matter concentrations of the effluent water quality are all low, and the emission indicators can be stably met. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 : is a schematic diagram of a process flow of a method for treating pharmaceutical wastewater in an embodiment of the present invention. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] The high-salt pharmaceutical wastewater used for the following examples and comparative examples of the present application has a COD concentration of 10,000 mg / L, a SS concentration of 700 mg / L, a TN concentration of 1,200 mg / L, a TP concentration of 30 mg / L, and a salt concentration of 20,000 mg / L. The present application adopts a combination of physical and chemical methods and biochemical methods to treat high-salt pharmaceutical wastewater. The salt content in the high-salt pharmaceutical wastewater is reduced to meet the requirements of biochemical treatment by evaporation and salt precipitation technology. After the water quality and water quantity are adjusted with general pharmaceutical wastewater, it is treated by ozone catalytic oxidation to convert phenol, cyanide and other pollutants in the water into non-toxic or slightly toxic substances. At the same time, it effectively decomposes organic matter such as sodium alkylbenzene sulfonate (ABS), protein, amino acids, organic amines, lignin, humus, heterocyclic compounds and chain unsaturated compounds, etc., to improve the biodegradability of the wastewater. The anaerobic bacteria in the multi-stage anoxic tank convert starch, Fiber, protein and other macromolecular organic matter are hydrolyzed into organic acid to reduce COD. Ammonia nitrogen in the wastewater undergoes nitrification reaction under the action of nitrifying bacteria in multi-stage aerobic pools, and organic pollutants in the wastewater are oxidized and decomposed into CO2 and H2O, completing the large-scale removal of organic matter and reducing ammonia nitrogen in the water. The residual difficult-to-degrade organic matter in the wastewater is re-oxidized in the secondary ozone catalytic pool, so that the organic matter in the wastewater can be removed efficiently. After the activated carbon filter absorbs color, odor and organic matter, the effluent can be used for reuse and discharge. The COD and salinity of the effluent are low, and the effluent water quality is stable and meets the standards.

[0037] Example 1

[0038] A method for treating pharmaceutical wastewater, such as Figure 1 As shown, the following steps are included:

[0039] (1) Pharmaceutical wastewater is divided into high-salt pharmaceutical wastewater with a salt concentration higher than 10000 mg / L and general pharmaceutical wastewater with a salt concentration lower than or equal to 10000 mg / L. The salt in the wastewater will affect the efficiency of subsequent biochemical treatment. In this embodiment, the high-salt pharmaceutical wastewater is first treated by continuous evaporation and salt precipitation. The evaporation and salt precipitation is a continuous operation mode with an evaporation temperature of 95°C. The waste salt (residue and high-concentration concentrated liquid) after evaporation and salt precipitation is outsourced for treatment. The separated evaporation condensate and general pharmaceutical wastewater enter the regulating tank for water quality and water quantity adjustment. The salt concentration of the effluent from the regulating tank is adjusted to 2000 mg / L to achieve uniform effluent.

[0040] (2) the effluent from step (1) enters a primary sedimentation tank to remove solid suspended particles with higher density in the wastewater and reduce the organic load of subsequent biological treatment;

[0041] (3) The effluent from step (2) enters a primary ozone catalytic oxidation tank, and adopts "ozone micro-nano bubble + ultraviolet light" catalytic oxidation technology to enhance the oxidation efficiency of ozone, effectively remove organic matter and improve the biodegradability of wastewater, including an ozone micro-nano bubble generator and an ultraviolet lamp. The microbubble generator in the ozone micro-nano bubble generator adopts a gas-liquid mixing tube technology, controls the gas-water ratio to be 1:10, and the pressure before the tube is 0.5 MPa. The microbubbles with a size of 20-30 μm account for more than 90%. The ozone generated by the ozone generator in the ozone micro-nano bubble generator is mixed with the wastewater to generate a high concentration of ozone microbubble mixed gas and liquid in the microbubble generator, which is aerated in the primary ozone catalytic oxidation tank through a stainless steel aeration head. The ozone dosage is 180 mg / L, the treatment time is 1.5 h, the ultraviolet light wavelength is 254 nm, and the intensity is 85 mw / cm 2 ;

[0042] (4) the effluent from step (3) enters a primary anoxic tank for anaerobic biological treatment, and the DO is controlled to be 0.15 mg / L. A stirring device is installed in the primary anoxic tank. Under the action of anaerobic bacteria, macromolecular organic matter such as starch, fiber, and protein in the wastewater is hydrolyzed into organic acids, thereby further improving the biodegradability of the wastewater. At the same time, denitrification reaction is carried out under the action of denitrifying bacteria to reduce the total nitrogen in the wastewater.

[0043] (5) The effluent from step (4) enters a primary aerobic tank for aerobic biological treatment, and the DO is controlled to be 4 mg / L. The ammonia nitrogen in the water undergoes nitrification reaction under the action of nitrifying bacteria, and the organic pollutants in the water are oxidized and decomposed into CO2 and H2O, thereby completing the removal of a large amount of organic matter and reducing the ammonia nitrogen in the water;

[0044] (6) The effluent from step (5) enters a secondary anoxic tank for anaerobic biological treatment, and the DO is controlled to be 0.15 mg / L. Microorganisms in the wastewater further reduce nitrates and nitrites to nitrogen gas through reduction, thereby further reducing the total nitrogen in the effluent;

[0045] (7) The effluent from step (6) enters a secondary aerobic tank for aerobic biological treatment, and the DO is controlled at 5 mg / L. The wastewater is further degraded by organic matter under the action of aerobic microorganisms;

[0046] (8) The effluent from step (7) enters the secondary sedimentation tank, where the wastewater is precipitated, the mud and water are separated, and the sludge is discharged into the sludge concentration tank. In order to ensure the sludge concentration in the pre-anoxic tank and the denitrification efficiency of the wastewater, part of the sludge is returned to the primary anoxic tank and the secondary anoxic tank, and the effluent enters the next step of the deep treatment system;

[0047] (9) The effluent from step (8) enters a secondary ozone catalytic oxidation tank. The pharmaceutical wastewater has a high COD concentration, and the effluent from the secondary sedimentation tank still contains a certain amount of difficult-to-degrade organic matter. The "ozone micro-nano bubble + ultraviolet light" catalytic oxidation technology is used to enhance the oxidation efficiency of ozone and further remove the residual difficult-to-degrade organic matter in the effluent from the secondary sedimentation tank. The method includes an ozone micro-nano bubble generator and an ultraviolet lamp. The microbubble generator in the ozone micro-nano bubble generator adopts a gas-liquid mixing tube technology to control the gas-water ratio to 1:10, the pressure before the tube to 0.5 MPa, and the microbubble size of 20-30 μm accounts for more than 90%. The ozone dosage in the ozone micro-nano bubble generator is 20 mg / L, the treatment time is 1.5 h, the ultraviolet light wavelength is 254 nm, and the intensity is 85 mw / cm 2 ;

[0048] (10) The effluent from step (9) enters an activated carbon filter tank, where activated carbon is used as the filter layer filler. The filter tank is in a continuous operation mode and is equipped with a backwash system to thoroughly adsorb and remove the color, odor, and organic matter in the wastewater. The wastewater then enters a clean water tank for reuse or discharge;

[0049] Among them, the sludge produced in the primary sedimentation tank and the secondary sedimentation tank enters the sludge thickening tank, and polyacrylamide is added. The concentrated sludge enters the filter press for dehydration, and the dehydrated sludge is transported out for disposal. The supernatant of the sludge thickening tank and the filtrate produced by the filter press dehydration can be reused in the regulating tank to adjust the water quantity and water quality.

[0050] Comparative Example 1

[0051] A method for treating pharmaceutical wastewater comprises the following steps:

[0052] (1) High-salt pharmaceutical wastewater is first treated by continuous evaporation and salt precipitation. The evaporation and salt precipitation is a continuous operation mode with an evaporation temperature of 95°C. The waste salt (residue and high-concentration concentrate) after evaporation and salt precipitation is outsourced for treatment. The separated evaporation condensate and general pharmaceutical wastewater enter the regulating tank together for water quality and water quantity adjustment. The salt concentration of the effluent from the regulating tank is adjusted to 2000 mg / L to achieve uniform effluent.

[0053] (2) the effluent from step (1) enters a primary sedimentation tank to remove solid suspended particles with higher density in the wastewater;

[0054] (3) the effluent from step (2) enters a primary anoxic tank for anaerobic biological treatment, and the DO is controlled to be 0.15 mg / L, and a stirring device is installed in the primary anoxic tank;

[0055] (4) The effluent from step (3) enters a primary aerobic tank for aerobic biological treatment, and the DO is controlled at 4 mg / L;

[0056] (5) The effluent from step (4) enters a secondary anoxic tank for anaerobic biological treatment, and controls the DO to 0.15 mg / L;

[0057] (6) The effluent from step (5) enters a secondary aerobic tank for aerobic biological treatment, and the DO is controlled at 5 mg / L;

[0058] (7) The effluent from step (6) enters the secondary sedimentation tank, where the wastewater is precipitated and the mud and water are separated. The sludge is discharged into the sludge concentration tank. In order to ensure the sludge concentration in the pre-anoxic tank and the denitrification efficiency of the wastewater, part of the sludge is returned to the primary anoxic tank and the secondary anoxic tank. The effluent enters the clear water tank for reuse or discharge.

[0059] Comparative Example 2

[0060] A method for treating pharmaceutical wastewater comprises the following steps:

[0061] (1) High-salt pharmaceutical wastewater is first treated by continuous evaporation and salt precipitation. The evaporation and salt precipitation is a continuous operation mode with an evaporation temperature of 95°C. The waste salt (residue and high-concentration concentrate) after evaporation and salt precipitation is outsourced for treatment. The separated evaporation condensate and general pharmaceutical wastewater enter the regulating tank for water quality and water quantity adjustment. The salt concentration of the effluent from the regulating tank is adjusted to 2000 mg / L to achieve uniform effluent.

[0062] (2) the effluent from step (1) enters a primary sedimentation tank to remove solid suspended particles with higher density in the wastewater;

[0063] (3) The effluent from step (2) enters a primary ozone catalytic oxidation tank, using a common ozone catalytic oxidation technology, including an ozone generator, the ozone generated by the ozone generator is aerated in the primary ozone catalytic oxidation tank through a stainless steel aeration head, the ozone dosage is 180 mg / L, and the treatment time is 1.5 h;

[0064] (4) the effluent from step (3) enters a primary anoxic tank for anaerobic biological treatment, and the DO is controlled to be 0.15 mg / L, and a stirring device is installed in the primary anoxic tank;

[0065] (5) The effluent from step (4) enters a primary aerobic tank for aerobic biological treatment, and the DO is controlled at 4 mg / L;

[0066] (6) The effluent from step (5) enters a secondary anoxic tank for anaerobic biological treatment, and controls the DO to 0.15 mg / L;

[0067] (7) The effluent from step (6) enters a secondary aerobic tank for aerobic biological treatment, and controls the DO to 5 mg / L;

[0068] (8) The effluent from step (7) enters the secondary sedimentation tank, where the wastewater is precipitated, the mud and water are separated, and the sludge is discharged into the sludge concentration tank. In order to ensure the sludge concentration in the pre-anoxic tank and the denitrification efficiency of the wastewater, part of the sludge is returned to the primary anoxic tank and the secondary anoxic tank, and the effluent enters the next step of the deep treatment system;

[0069] (9) The effluent from step (8) enters a secondary ozone catalytic oxidation tank, using a conventional ozone catalytic oxidation technology, including an ozone generator, an ozone dosage of 20 mg / L, and a treatment time of 1.5 h;

[0070] (10) The effluent from step (9) enters an activated carbon filter tank, where activated carbon is used as the filter layer filler. The filter tank is in continuous operation mode and is equipped with a backwash system. The effluent then enters a clean water tank for reuse or discharge.

[0071] Comparative Example 3

[0072] A method for treating pharmaceutical wastewater comprises the following steps:

[0073] (1) High-salt pharmaceutical wastewater is first treated by continuous evaporation and salt precipitation. The evaporation and salt precipitation is a continuous operation mode with an evaporation temperature of 95°C. The waste salt (residue and high-concentration concentrate) after evaporation and salt precipitation is outsourced for treatment. The separated evaporation condensate and general pharmaceutical wastewater enter the regulating tank together for water quality and water quantity adjustment. The salt concentration of the effluent from the regulating tank is adjusted to 2000 mg / L to achieve uniform effluent.

[0074] (2) the effluent from step (1) enters a primary sedimentation tank to remove solid suspended particles with higher density in the wastewater;

[0075] (3) the effluent from step (2) enters a primary anoxic tank for anaerobic biological treatment, and the DO is controlled to be 0.15 mg / L, and a stirring device is installed in the primary anoxic tank;

[0076] (4) The effluent from step (3) enters a primary aerobic tank for aerobic biological treatment, and the DO is controlled at 4 mg / L;

[0077] (5) The effluent from step (4) enters a secondary anoxic tank for anaerobic biological treatment, and controls the DO to 0.15 mg / L;

[0078] (6) The effluent from step (5) enters a secondary aerobic tank for aerobic biological treatment, and the DO is controlled at 5 mg / L;

[0079] (7) The effluent from step (6) enters the secondary sedimentation tank, where the wastewater is precipitated, the mud and water are separated, and the sludge is discharged into the sludge concentration tank. In order to ensure the sludge concentration in the pre-anoxic tank and the denitrification efficiency of the wastewater, part of the sludge is returned to the primary anoxic tank and the secondary anoxic tank, and the effluent enters the next step of the deep treatment system;

[0080] (8) The effluent from step (7) enters an ozone catalytic oxidation pool, and adopts an "ozone micro-nano bubble + ultraviolet light" catalytic oxidation technology, including an ozone micro-nano bubble generator and an ultraviolet lamp. The microbubble generator in the ozone micro-nano bubble generator adopts a gas-liquid mixing tube technology, and the gas-water ratio is controlled to be 1:10, the pressure before the tube is 0.5 MPa, and the microbubbles generated are 20-30 μm in size, accounting for more than 90%. The ozone dosage in the ozone micro-nano bubble generator is 20 mg / L, the treatment time is 1.5 h, the ultraviolet light wavelength is 254 nm, and the intensity is 85 mw / cm 2 ;

[0081] (9) The effluent from step (8) enters an activated carbon filter tank, which uses activated carbon as the filter layer filler. The filter tank is in continuous operation mode and is equipped with a backwash system. The effluent then enters a clean water tank for reuse or discharge.

[0082] Comparative Example 4

[0083] A method for treating pharmaceutical wastewater comprises the following steps:

[0084] (1) High-salt pharmaceutical wastewater is first treated by continuous evaporation and salt precipitation. The evaporation and salt precipitation is a continuous operation mode with an evaporation temperature of 95°C. The waste salt (residue and high-concentration concentrate) after evaporation and salt precipitation is outsourced for treatment. The separated evaporation condensate and general pharmaceutical wastewater enter the regulating tank for water quality and water quantity adjustment. The salt concentration of the effluent from the regulating tank is adjusted to 2000 mg / L to achieve uniform effluent.

[0085] (2) the effluent from step (1) enters a primary sedimentation tank to remove solid suspended particles with higher density in the wastewater;

[0086] (3) The effluent from step (2) enters an ozone catalytic oxidation pool, and adopts an "ozone micro-nano bubble generator ultraviolet light" catalytic oxidation technology, including an ozone micro-nano bubble generator and an ultraviolet lamp. The microbubble generator in the ozone micro-nano bubble generator adopts a gas-liquid mixing tube technology, and the gas-water ratio is controlled to be 1:10, the pressure before the tube is 0.5 MPa, and the microbubbles generated are 20-30 μm in size, accounting for more than 90%. The ozone dosage in the ozone micro-nano bubble generator is 180 mg / L, the treatment time is 1.5 h, the ultraviolet light wavelength is 254 nm, and the intensity is 85 mw / cm 2 ;

[0087] (4) the effluent from step (3) enters a primary anoxic tank for anaerobic biological treatment, and the DO is controlled to be 0.15 mg / L, and a stirring device is installed in the primary anoxic tank;

[0088] (5) The effluent from step (4) enters a primary aerobic tank for aerobic biological treatment, and the DO is controlled at 4 mg / L;

[0089] (6) The effluent from step (5) enters a secondary anoxic tank for anaerobic biological treatment, and controls the DO to 0.15 mg / L;

[0090] (7) The effluent from step (6) enters a secondary aerobic tank for aerobic biological treatment, and controls the DO to 5 mg / L;

[0091] (8) The effluent from step (7) enters the secondary sedimentation tank, where the wastewater is precipitated, the mud and water are separated, and the sludge is discharged into the sludge concentration tank. In order to ensure the sludge concentration in the pre-anoxic tank and the denitrification efficiency of the wastewater, part of the sludge is returned to the primary anoxic tank and the secondary anoxic tank, and the effluent enters the next step of the deep treatment system;

[0092] (9) The effluent from step (8) enters an activated carbon filter tank, which uses activated carbon as the filter layer filler. The filter tank is in continuous operation mode and is equipped with a backwash system. The effluent then enters a clean water tank for reuse or discharge.

[0093] Comparative Example 5

[0094] A method for treating pharmaceutical wastewater comprises the following steps:

[0095] (1) High-salt pharmaceutical wastewater is not treated by evaporation and salt precipitation, but directly enters the regulating pond together with general pharmaceutical wastewater for water quality and water quantity regulation. The salt concentration of the effluent from the regulating pond is 8000 mg / L;

[0096] (2) the effluent from step (1) enters a primary sedimentation tank to remove solid suspended particles with higher density in the wastewater;

[0097] (3) The effluent from step (2) enters a primary ozone catalytic oxidation pool, using "ozone micro-nano bubble + ultraviolet light" catalytic oxidation technology, including an ozone micro-nano bubble generator and an ultraviolet lamp. The microbubble generator in the ozone micro-nano bubble generator adopts a gas-liquid mixing tube technology, controls the gas-water ratio to be 1:10, and the pressure before the tube is 0.5 MPa. The microbubbles with a size of 20-30 μm account for more than 90%. The ozone dosage in the ozone micro-nano bubble generator is 180 mg / L, the treatment time is 1.5 h, the ultraviolet light wavelength is 254 nm, and the intensity is 85 mw / cm 2 ;

[0098] (4) the effluent from step (3) enters a primary anoxic tank for anaerobic biological treatment, and the DO is controlled to be 0.15 mg / L, and a stirring device is installed in the primary anoxic tank;

[0099] (5) The effluent from step (4) enters a primary aerobic tank for aerobic biological treatment, and the DO is controlled at 4 mg / L;

[0100] (6) The effluent from step (5) enters a secondary anoxic tank for anaerobic biological treatment, and controls the DO to 0.15 mg / L;

[0101] (7) The effluent from step (6) enters a secondary aerobic tank for aerobic biological treatment, and controls the DO to 5 mg / L;

[0102] (8) The effluent from step (7) enters the secondary sedimentation tank, where the wastewater is precipitated, the mud and water are separated, and the sludge is discharged into the sludge concentration tank. In order to ensure the sludge concentration in the pre-anoxic tank and the denitrification efficiency of the wastewater, part of the sludge is returned to the primary anoxic tank and the secondary anoxic tank, and the effluent enters the next step of the deep treatment system;

[0103] (9) The effluent from step (8) enters a secondary ozone catalytic oxidation pool, and adopts an "ozone micro-nano bubble + ultraviolet light" catalytic oxidation technology, including an ozone micro-nano bubble generator and an ultraviolet lamp. The microbubble generator in the ozone micro-nano bubble generator adopts a gas-liquid mixing tube technology, controls the gas-water ratio to be 1:10, and the pressure before the tube is 0.5 MPa. The microbubbles with a size of 20-30 μm account for more than 90%. The ozone dosage in the ozone micro-nano bubble generator is 20 mg / L, the treatment time is 1.5 h, the ultraviolet light wavelength is 254 nm, and the intensity is 85 mw / cm 2 ;

[0104] (10) The effluent from step (9) enters an activated carbon filter tank, where activated carbon is used as the filter layer filler. The filter tank is in continuous operation mode and is equipped with a backwash system. The effluent then enters a clean water tank for reuse or discharge.

[0105] The effluent of the wastewater treated in the embodiment and the comparative example was tested for COD (chemical oxygen demand), SS (suspended solids), TN (total nitrogen), TP (total phosphorus) and salt concentration. The COD test was carried out in accordance with the "Determination of Chemical Oxygen Demand of Water Quality by Potassium Dichromate Method" (HJ828-2017) standard, the SS test was carried out in accordance with the "Determination of Suspended Solids in Water Quality by Gravimetric Method" (GB 11901-89) standard, the TN test was carried out in accordance with the "Determination of Total Nitrogen in Water Quality by Alkaline Potassium Persulfate Digestion Ultraviolet Spectrophotometry" (HJ 636-2012) standard, the TP test was carried out in accordance with the "Determination of Total Phosphorus in Water Quality by Ammonium Molybdate Spectrophotometry" (GB 11893-89) standard, and the wastewater discharge was carried out in accordance with the "Emission Standard of Water Pollutants for Chemical Synthesis Pharmaceutical Industry" (GB 21904-2008). The test results are shown in Table 1 below.

[0106] Table 1 - Test results of effluent from high-salt pharmaceutical wastewater treated in the present application examples and comparative examples

[0107]

[0108]

[0109] As shown in Table 1, compared with Example 1, the wastewater of Comparative Examples 1 and 3 was not treated in the primary ozone oxidation tank after precipitation in the primary sedimentation tank, but directly entered the subsequent anoxic tank and aerobic tank for biological treatment. Ozone oxidation treatment can convert pollutants such as water-based phenol and cyanide into non-toxic or slightly toxic substances, oxidize metal ions into metal oxides through ozone and separate them out, and effectively decompose organic matter. Since Comparative Example 1 did not undergo ozone oxidation treatment, there were more metal ions and toxic pollutants in the wastewater during the biochemical treatment process, and the biodegradability was poor, which would affect the growth of anaerobic bacteria and aerobic bacteria, resulting in low decomposition efficiency of macromolecular organic matter in the wastewater, and the chemical oxygen demand, total nitrogen, and total phosphorus concentrations of the final treated effluent were significantly higher than those of Example 1. In addition, the wastewater of Comparative Example 1 was not deeply treated in an activated carbon filter, resulting in a higher concentration of suspended matter in the wastewater.

[0110] As shown in Table 1, compared with Example 1, the wastewater in Comparative Example 2 was subjected to ordinary ozone oxidation treatment in the primary ozone oxidation tank and the secondary ozone oxidation tank, without microbubble treatment ozone and ultraviolet lamp assistance, resulting in low ozone oxidation efficiency. The pharmaceutical wastewater has the characteristics of high COD concentration and high ammonia nitrogen concentration, resulting in the water quality of the effluent after the final treatment failing to meet the standards, and the chemical oxygen demand, total nitrogen and total phosphorus concentrations of the effluent are higher than those in Example 1.

[0111] As shown in Table 1, compared with Example 1, the wastewater of Comparative Example 4 was not treated in a secondary ozone oxidation tank after biochemical treatment and precipitation in the anoxic tank and aerobic tank, resulting in the presence of organic pollutants in the wastewater that were not completely decomposed by biochemical treatment, and the activated carbon filter was unable to effectively intercept and filter these difficult-to-decompose organic pollutants, resulting in the chemical oxygen demand, total nitrogen, and total phosphorus concentrations of the final effluent being slightly higher than those in Example 1.

[0112] As shown in Table 1, compared with Example 1, the high-salt wastewater in Comparative Example 5 was not subjected to evaporation and salt precipitation treatment, resulting in higher salinity in the effluent from the regulating tank and low biodegradability. During the biochemical treatment stage, anaerobic bacteria and aerobic bacteria were difficult to grow and reproduce in the wastewater with high salt concentration, resulting in a serious reduction in biochemical treatment efficiency and a significant decrease in the decomposition of organic matter. The effluent water still had higher COD, suspended solids, total phosphorus, and total nitrogen concentrations.

[0113] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. It is particularly pointed out that for those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for treating pharmaceutical wastewater, characterized in that: The following steps are involved: (1) The pharmaceutical wastewater enters the regulating tank for water quality and water quantity adjustment, and the effluent enters the primary sedimentation tank to precipitate suspended particles; (2) the effluent from the primary sedimentation tank enters a primary ozone catalytic oxidation tank for oxidation treatment; (3) the effluent from the primary ozone catalytic oxidation tank enters a biochemical treatment process, the biochemical treatment process includes a multi-stage anoxic tank and a multi-stage aerobic tank treatment; (4) the effluent from the biochemical treatment process enters a secondary sedimentation tank, where the wastewater is precipitated and the mud and water are separated; (5) the effluent from the secondary sedimentation tank is fed into a secondary ozone catalytic oxidation tank for oxidation treatment; (6) the effluent from the secondary ozone catalytic oxidation tank enters an activated carbon filter for treatment and then enters a clean water tank; Wherein, in step (1), the pharmaceutical wastewater includes high-salt pharmaceutical wastewater with a salt concentration higher than 10000 mg / L and general pharmaceutical wastewater with a salt concentration lower than or equal to 10000 mg / L, the high-salt pharmaceutical wastewater is preliminarily subjected to evaporation and salt precipitation treatment, and the separated evaporation condensate and general pharmaceutical wastewater enter the regulating tank together, and the salt concentration of the effluent from the regulating tank is adjusted to be less than 4000 mg / L; In steps (2) and (5), the primary ozone catalytic oxidation tank and the secondary ozone catalytic oxidation tank use ozone micro-nano bubbles and ultraviolet lamp technology for catalytic oxidation.

2. A method for treating pharmaceutical wastewater as claimed in claim 1, characterized in that: In step (1), the evaporation and salt precipitation temperature of the high-salt pharmaceutical wastewater is 90-100°C.

3. The method for treating pharmaceutical wastewater according to claim 1, characterized in that: In step (3), the biochemical treatment process includes a primary anoxic tank, a primary aerobic tank, a secondary anoxic tank and a secondary aerobic tank for sequential treatment.

4. A method for treating pharmaceutical wastewater as claimed in claim 3, characterized in that: In step (3), the primary anoxic tank and the secondary anoxic tank control DO≤0.3 mg / L.

5. A method for treating pharmaceutical wastewater as claimed in claim 3, characterized in that: In step (3), the DO of the primary aerobic pool is controlled at 2-6 mg / L, and the DO of the secondary aerobic pool is controlled at 3-6 mg / L.

6. A method for treating pharmaceutical wastewater according to claim 1, characterized in that: In steps (2) and (5), the primary ozone catalytic oxidation tank and the secondary ozone catalytic oxidation tank are provided with an ozone micro-nano bubble generator and an ultraviolet lamp.

7. A method for treating pharmaceutical wastewater as claimed in claim 6, characterized in that: In step (2), the ozone dosage of the ozone micro-nano bubble generator is 150-200 mg / L, the microbubble size is 10-50 μm, the treatment time is 1-2 hours, the ultraviolet light wavelength is 185-400 nm, and the intensity is 50-200 mw / cm 2 .

8. A method for treating pharmaceutical wastewater as claimed in claim 6, characterized in that: In step (5), the ozone dosage of the ozone micro-nano bubble generator is 15-20 mg / L, the treatment time is 1-2 hours, the ultraviolet light wavelength is 185-400 nm, and the intensity is 50-200 mw / cm 2 .

9. A method for treating pharmaceutical wastewater according to claim 1, characterized in that: In steps (1) and (4), the sludge produced in the primary sedimentation tank and the secondary sedimentation tank enters the sludge thickening tank, and polyacrylamide is added. The concentrated sludge enters the filter press for dehydration, and the supernatant of the sludge thickening tank and the filtrate produced by the filter press dehydration are refluxed into the regulating tank to regulate the water quantity and water quality.

10. The method for treating pharmaceutical wastewater according to claim 1, characterized in that: In step (4), part of the sludge precipitated in the secondary sedimentation tank is returned to the primary anoxic tank and the secondary anoxic tank for sludge replenishment.

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