Device and process for treating pharmaceutical wastewater by internal electrolysis method

Abstract

The invention discloses a device and process for treating pharmaceutical wastewater through an internal electrolysis method. The device comprises a pretreatment unit, an internal electrolysis reaction unit, a precipitation separation unit, a pH adjusting unit and a control system which are sequentially connected. The internal electrolytic reaction unit comprises a reaction tower body, the top of the reaction tower body is provided with a water inlet, and the bottom is provided with a water outlet; a supporting layer, an iron-carbon micro-electrolysis filler layer, a catalytic oxidation layer and a biological membrane layer are sequentially arranged in the reaction tower body from bottom to top, the iron-carbon micro-electrolysis filler layer comprises an iron-carbon composite filler, and the mass ratio of iron to carbon in the iron-carbon composite filler is (1: 1)-(3: 1). The internal electrolysis reaction unit with a multi-level filling structure is adopted, iron-carbon micro-electrolysis, catalytic oxidation and biodegradation are organically combined to form a synergistic effect, the removal efficiency of refractory organics in the pharmaceutical wastewater is remarkably improved, and the COD removal rate can reach 80% or above.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment, and more particularly to an apparatus and process for treating pharmaceutical wastewater by internal electrolysis. Background Technology

[0002] Pharmaceutical wastewater is characterized by its complex composition, high concentration of organic matter, high toxicity, and poor biodegradability. If it is discharged directly without effective treatment, it will cause serious environmental pollution.

[0003] Internal electrolysis (also known as micro-electrolysis) is a highly efficient wastewater treatment technology. Its principle involves using iron filings and carbon particles to form a galvanic cell, removing pollutants from wastewater through oxidation-reduction, flocculation, sedimentation, and adsorption. However, traditional internal electrolysis treatment devices suffer from low reaction efficiency, easy packing material caking, and unstable treatment effects, making it difficult to meet the treatment requirements of pharmaceutical wastewater.

[0004] Therefore, developing an efficient, stable, and durable internal electrolysis method for treating pharmaceutical wastewater is of significant practical importance. Summary of the Invention

[0005] The first objective of this invention is to provide an apparatus for treating pharmaceutical wastewater using an internal electrolysis method, which has the advantages of improving the treatment efficiency and stability of pharmaceutical wastewater.

[0006] To achieve the above-mentioned objectives, the technical solution of this invention is as follows: An apparatus for treating pharmaceutical wastewater using internal electrolysis includes a pretreatment unit, an internal electrolysis reaction unit, a sedimentation and separation unit, a pH adjustment unit, and a control system connected in sequence. The internal electrolysis reaction unit includes a reaction tower with an inlet at the top and an outlet at the bottom. The reaction tower contains, from bottom to top, a support layer, an iron-carbon micro-electrolysis packing layer, a catalytic oxidation layer, and a biofilm layer. The iron-carbon micro-electrolysis packing layer includes an iron-carbon composite packing, wherein the mass ratio of iron to carbon in the iron-carbon composite packing is 1:1 to 3:1.

[0007] By adopting the above technical solution and employing a multi-level packed internal electrolysis reaction unit, iron-carbon micro-electrolysis, catalytic oxidation, and biodegradation are organically combined to form a synergistic effect, significantly improving the removal efficiency of recalcitrant organic matter in pharmaceutical wastewater, with a COD removal rate exceeding 80%. The pretreatment unit effectively intercepts large particulate impurities and floating matter in the wastewater, preventing blockages in subsequent pipelines or equipment. The support layer primarily supports the upper packing layer while ensuring uniform wastewater distribution and preventing localized water accumulation. The iron-carbon composite packing forms numerous micro-galvanic cells in the wastewater, with iron acting as the anode for oxidation and carbon as the cathode for reduction, forming highly adsorbent flocs that can adsorb and remove organic pollutants from the wastewater.

[0008] Preferably, the catalytic oxidation layer comprises a mixture of a supported catalyst and activated carbon, wherein the supported catalyst is activated carbon particles supported with copper, nickel or cobalt, and the mass ratio of the supported catalyst to the activated carbon is 1:5 to 1:10.

[0009] By adopting the above technical solution, this layer can utilize the catalytic effect of the catalyst to promote the oxidative decomposition of recalcitrant organic matter in wastewater, while activated carbon can adsorb some organic matter, further improving the pollutant removal efficiency.

[0010] Preferably, the biofilm synergistic layer comprises a porous ceramic carrier and a microbial agent attached to the porous ceramic carrier, wherein the porosity of the porous ceramic carrier is 50%–70%.

[0011] By adopting the above technical solution, microbial agents are attached to the porous ceramic carrier to form a biofilm. The microorganisms in the biofilm can degrade organic pollutants in wastewater through metabolism, forming a synergistic effect with iron-carbon micro-electrolysis and catalytic oxidation, which significantly improves the removal effect of recalcitrant organic matter.

[0012] Preferably, the sedimentation separation unit includes an inclined tube sedimentation tank and a sludge thickening tank. The inlet of the inclined tube sedimentation tank is connected to the outlet of the internal electrolysis reaction unit through a conveying pipeline, and the bottom sludge discharge port of the inclined tube sedimentation tank is connected to the sludge thickening tank through a pipeline. The inclined tube sedimentation tank is equipped with inclined tube packing material, and the inclined tube packing material has an inclination angle of 60 degrees.

[0013] By adopting the above technical solutions, the inclined tube packing can increase the sedimentation area, shorten the settling distance of suspended solids, improve sedimentation efficiency, and allow wastewater to stay in the tank for a longer time, with flocs and suspended solids settling on the surface of the inclined tube.

[0014] Preferably, the pH adjustment unit includes a first pH adjustment tank and a second pH adjustment tank. The first pH adjustment tank is connected to the pretreatment unit and the internal electrolysis reaction unit via pipelines, and the second pH adjustment tank is connected to the precipitation separation unit via pipelines. Both the first pH adjustment tank and the second pH adjustment tank are equipped with a stirring device and a pH sensor, and the pH sensor is electrically connected to the control system.

[0015] By adopting the above technical solution, the pH sensor is electrically connected to the control system, and alkaline solution is automatically added according to the monitoring results to adjust the pH value to 6-9, ensuring that the pH value of the effluent meets the discharge standards. The second objective of this invention is to provide a process for treating pharmaceutical wastewater using the above-mentioned apparatus. This process is simple to operate, has low energy consumption, is highly adaptable, and can achieve efficient purification of pharmaceutical wastewater.

[0016] To achieve the above-mentioned objectives, the technical solution of this invention comprises the following steps: S1. Pretreatment: Pharmaceutical wastewater is introduced into the pretreatment unit, first passing through a bar screen to remove large particulate impurities and floating matter, and then entering a sedimentation tank for sedimentation treatment, with a sedimentation time of 1-2 hours. S2, pH adjustment: The pretreated wastewater is introduced into the first pH adjustment tank, and acid solution is added to adjust the pH value of the wastewater to 2-4. S3, Internal Electrolysis Reaction: The pH-adjusted wastewater is pumped into the internal electrolysis reaction unit. The residence time of the wastewater in the reaction tower is controlled at 60-120 minutes, the reaction temperature is controlled at 25-35℃, and intermittent aeration is adopted. S4. Sedimentation and separation: The wastewater after the internal electrolysis reaction is introduced into the inclined tube sedimentation tank for sedimentation and separation. The sedimentation time is 1-1.5 hours. The supernatant enters the next treatment unit, and the bottom sludge is discharged into the sludge thickening tank. S5. Effluent adjustment: The supernatant after sedimentation and separation is introduced into the second pH adjustment tank. Alkali solution is added to adjust the pH value to 6-9. After meeting the standard, it is discharged or reused.

[0017] Preferably, in step S3, the ratio of the aeration time to the aeration stop time during intermittent aeration is 1:2 to 1:3.

[0018] Preferably, in step S3, the backwashing cycle of the iron-carbon micro-electrolysis packing layer is 7-15 days, and the backwashing is carried out by a combination of air and water, with a backwashing time of 10-15 minutes.

[0019] The beneficial effects of this invention are: 1. The device of the present invention adopts an internal electrolysis reaction unit with a multi-level packed structure, which organically combines iron-carbon micro-electrolysis, catalytic oxidation and biodegradation to form a synergistic effect, significantly improving the removal efficiency of refractory organic matter in pharmaceutical wastewater, with a COD removal rate of over 80%; at the same time, the multi-level packed structure can buffer water quality fluctuations, and the biofilm layer can adapt to low concentrations of organic matter in the influent, ensuring stable operation of the system.

[0020] 2. The various units of the device are closely connected and rationally laid out. The control system enables automated operation, which is simple to operate and stable and reliable.

[0021] 3. Compared with traditional treatment methods, this invention has the advantages of low operating cost, low energy consumption, and low sludge production, and has good economic and environmental benefits, and is easy to promote and apply in industrial applications. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the present invention.

[0023] Figure 2 for Figure 1 Enlarged view of part A in the middle.

[0024] Figure 3 This is a schematic diagram of the backwashing device.

[0025] Figure 4 This is a schematic diagram of the aeration device.

[0026] Figure 5 This is a schematic diagram of the stirring device.

[0027] In the picture: 1. Pretreatment unit; 11. Bar screen filter; 12. Sedimentation tank; 2. Internal electrolysis reaction unit; 21. Reaction tower body; 22. Support layer; 23. Iron-carbon micro-electrolysis packing layer; 24. Catalytic oxidation layer; 25. Biofilm synergistic layer; 3. Sedimentation separation unit; 31. Inclined tube sedimentation tank; 311. Inclined tube packing; 32. Sludge thickening tank; 4. pH adjustment unit; 41. First pH adjustment tank; 42. Second pH adjustment tank; 43. Stirring device; 431. Motor; 432. Stirring shaft; 433. Stirring blades; 44. pH sensor; 5. Aeration device; 51. Aeration pump; 52. Aeration pipe; 53. Aerator; 6. Backwashing device; 61. Backwash water tank; 62. Backwash water pump; 63. Air compressor; 64. Water and air distribution mechanism. Detailed Implementation

[0028] The technical solutions in the embodiments of the present invention will now be clearly and completely described in conjunction with the accompanying drawings.

[0029] The described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0030] Example 1 like Figure 1 As shown, an apparatus for treating pharmaceutical wastewater using an internal electrolysis method includes a pretreatment unit 1, an internal electrolysis reaction unit 2, a sedimentation and separation unit 3, a pH adjustment unit 4, and a control system. The pretreatment unit 1 includes a bar screen 11 and a sedimentation tank 12. The bar screen 11 is equipped with a stainless steel bar screen with a pore size of 1 mm. The sedimentation tank 12 has a conical bottom with a cone angle of 75 degrees.

[0031] like Figure 1 and Figure 2As shown, the internal electrolysis reaction unit 2 includes a reaction tower body 21, lined with anti-corrosion material. The reaction tower body 21 is filled from bottom to top with a support layer 22, an iron-carbon micro-electrolysis packing layer 23, a catalytic oxidation layer 24, and a biofilm synergistic layer 25. The support layer 22 is laid with 70mm diameter pebbles to a height of 150mm. The iron-carbon micro-electrolysis packing layer 23 has an iron to carbon mass ratio of 1:1-3:1, preferably 2:1, a packing particle size of 5mm, and a filling height of 1000mm. The iron-carbon micro-electrolysis packing layer 23 forms numerous tiny galvanic cells in the wastewater, decomposing organic matter in the wastewater through oxidation-reduction reactions. The catalytic oxidation layer 24 is a mixture of copper-loaded activated carbon particles and activated carbon at a mass ratio of 1:8, with a filling height of 400mm. The catalytic oxidation layer 24 further promotes the oxidative decomposition of organic matter, improving treatment efficiency. The porous ceramic carrier provides a site for microorganisms to attach and grow, and the resulting biofilm can degrade organic pollutants in wastewater, forming a synergistic effect with internal electrolysis. The biofilm synergistic layer 25 uses a porous ceramic carrier with a porosity of 60% and a filling height of 300 mm.

[0032] like Figure 1 and Figure 3 As shown, a backwashing device 6 electrically connected to the control system is provided between the support layer 22 and the iron-carbon micro-electrolysis filler layer 23. The backwashing device 6 includes a backwashing water tank 61, a backwashing water pump 62, an air compressor 63, and a water and air distribution mechanism 64. The backwashing water tank 61 is connected to the inlet of the backwashing water pump 62 through a pipe. The inlet of the water and air distribution mechanism 64 is connected to the outlet of the backwashing water pump 62 through a pipe. The air inlet is connected to the outlet of the air compressor 63 through a pipe.

[0033] like Figure 1 and Figure 4 As shown, an aeration device 5 is provided at the bottom of the reaction tower body 21. The aeration device 5 includes an aeration pump 51, an aeration pipe 52, and several aerators 53. The aeration pipe 52 is laid at the bottom of the reaction tower body 21. The outlet of the aeration pump 51 is connected to the aeration pipe 52. Several aerators 53 are evenly distributed on the aeration pipe.

[0034] like Figure 1 As shown, the sedimentation separation unit 3 includes an inclined tube sedimentation tank 31 and a sludge thickening tank 32. The inlet of the inclined tube sedimentation tank 31 is connected to the outlet of the internal electrolysis reaction unit 2 through a conveying pipe, and the bottom sludge discharge port of the inclined tube sedimentation tank 31 is connected to the sludge thickening tank 32 through a pipe. The inclined tube sedimentation tank 31 is equipped with inclined tube packing material 311, and the inclined tube packing material 311 has an inclination angle of 60 degrees and a length of 1100 mm.

[0035] like Figure 1 and Figure 5As shown, the pH adjustment unit 4 includes a first pH adjustment tank 41 and a second pH adjustment tank 42. The first pH adjustment tank 41 is connected to the pretreatment unit 1 and the internal electrolysis reaction unit 2 via pipes, respectively. The second pH adjustment tank 42 is connected to the precipitation separation unit 3 via pipes. Both the first pH adjustment tank 41 and the second pH adjustment tank 42 are equipped with a stirring device 43 and a pH sensor 44. The stirring device 43 includes a motor 431, a stirring shaft 432 fixed to the motor 431, and stirring blades 433 fixed to the stirring shaft 432.

[0036] The control system adopts a PLC control system. The backwash water pump 62, air compressor 63, aeration pump 51, motor 431, and pH sensor 44 are electrically connected to the control system.

[0037] Example 2 A method for treating wastewater from a pharmaceutical factory using the apparatus described in Example 1. The raw wastewater has a COD of approximately 4500 mg / L and a pH of 7.5–8.5, and mainly contains antibiotic intermediates and solvents. The steps are as follows: Step 1: Introduce pharmaceutical wastewater into pretreatment unit 1, where it first passes through bar screen filtration device 11 to remove large particulate impurities and floating matter, and then enters sedimentation tank 12 for sedimentation for 1.5 hours.

[0038] Step 2: Introduce the pretreated wastewater into the first pH adjustment tank 41, and add sulfuric acid solution to adjust the pH value to 3.

[0039] Step 3: Pump the pH-adjusted wastewater into the internal electrolysis reaction unit 2, control the residence time to be 90 minutes, the reaction temperature to be 30℃, adopt intermittent aeration, and the ratio of aeration time to aeration stop time is 1:2. The backwashing cycle of the iron-carbon micro-electrolysis packing layer 23 is 10 days, and the air-water combined backwashing is adopted, with a backwashing time of 12 minutes.

[0040] Step 4: The wastewater after the internal electrolysis reaction is introduced into the inclined tube sedimentation tank 31 for sedimentation for 1.2 hours. The supernatant enters the next treatment unit, and the bottom sludge is discharged into the sludge thickening tank 32.

[0041] Step 5: Introduce the supernatant into the second pH adjustment tank 42, and add sodium hydroxide solution to adjust the pH value to 7.5; Step 6: Perform a combined air-water backwash on the iron-carbon layer every 10 days (water flush 10 L / (m²·s), air flush 20 L / (m²·s), lasting 12 minutes).

[0042] After the above process, the COD of the effluent is reduced to below 650 mg / L, the removal rate is over 85%, the color removal exceeds 90%, and the effluent is clear and meets the effluent standards.

[0043] The described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. An apparatus for treating pharmaceutical wastewater using an internal electrolysis method, characterized in that, It includes a pretreatment unit, an internal electrolysis reaction unit, a precipitation separation unit, a pH adjustment unit, and a control system connected in sequence; The internal electrolysis reaction unit includes a reaction tower body, with a water inlet at the top and a water outlet at the bottom. The reaction tower is provided with a support layer, an iron-carbon micro-electrolysis packing layer, a catalytic oxidation layer and a biofilm layer from bottom to top. The iron-carbon micro-electrolysis packing layer includes an iron-carbon composite packing, in which the mass ratio of iron to carbon is 1:1 to 3:

1.

2. The apparatus for treating pharmaceutical wastewater by internal electrolysis according to claim 1, characterized in that, The catalytic oxidation layer comprises a mixture of a supported catalyst and activated carbon. The supported catalyst is activated carbon particles supported with copper, nickel, or cobalt, and the mass ratio of the supported catalyst to the activated carbon is 1:5 to 1:

10.

3. The apparatus for treating pharmaceutical wastewater by internal electrolysis according to claim 2, characterized in that, The biofilm synergistic layer comprises a porous ceramic carrier and a microbial agent attached to the porous ceramic carrier, wherein the porosity of the porous ceramic carrier is 50%–70%.

4. The apparatus for treating pharmaceutical wastewater by internal electrolysis according to claim 1, characterized in that, The sedimentation and separation unit includes an inclined tube sedimentation tank and a sludge thickening tank. The inlet of the inclined tube sedimentation tank is connected to the outlet of the internal electrolysis reaction unit through a conveying pipeline, and the bottom sludge discharge port of the inclined tube sedimentation tank is connected to the sludge thickening tank through a pipeline. The inclined tube sedimentation tank is equipped with inclined tube packing material, and the inclined tube packing material is inclined at an angle of 60 degrees.

5. The apparatus for treating pharmaceutical wastewater by internal electrolysis according to claim 1, characterized in that, The pH adjustment unit includes a first pH adjustment tank and a second pH adjustment tank. The first pH adjustment tank is connected to the pretreatment unit and the internal electrolysis reaction unit via pipelines, and the second pH adjustment tank is connected to the precipitation separation unit via pipelines. Both the first pH adjustment tank and the second pH adjustment tank are equipped with a stirring device and a pH sensor, and the pH sensor is electrically connected to the control system.

6. A process for treating pharmaceutical wastewater using the apparatus described in any one of claims 1-5, characterized in that, Includes the following steps: S1. Pretreatment: Pharmaceutical wastewater is introduced into the pretreatment unit, first passing through a bar screen to remove large particulate impurities and floating matter, and then entering a sedimentation tank for sedimentation treatment, with a sedimentation time of 1-2 hours. S2, pH adjustment: The pretreated wastewater is introduced into the first pH adjustment tank, and acid solution is added to adjust the pH value of the wastewater to 2-4. S3, Internal Electrolysis Reaction: The pH-adjusted wastewater is pumped into the internal electrolysis reaction unit. The residence time of the wastewater in the reaction tower is controlled at 60-120 minutes, the reaction temperature is controlled at 25-35℃, and intermittent aeration is adopted. S4. Sedimentation and separation: The wastewater after the internal electrolysis reaction is introduced into the inclined tube sedimentation tank for sedimentation and separation. The sedimentation time is 1-1.5 hours. The supernatant enters the next treatment unit, and the bottom sludge is discharged into the sludge thickening tank. S5. Effluent adjustment: The supernatant after sedimentation and separation is introduced into the second pH adjustment tank. Alkali solution is added to adjust the pH value to 6-9. After meeting the standard, it is discharged or reused.

7. The process for treating pharmaceutical wastewater according to claim 6, characterized in that, In step S3, the ratio of the aeration time to the aeration stop time during intermittent aeration is 1:2 to 1:

3.

8. The process for treating pharmaceutical wastewater according to claim 6, characterized in that, Step S3 also includes periodic backwashing of the iron-carbon micro-electrolysis packing layer. The backwashing cycle is 7-15 days. The backwashing is performed using a combination of air and water, and the backwashing time is 10-15 minutes.

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