Efficient resource recycling and purifying treatment method for coating wastewater in automobile industry

Abstract

The invention relates to an efficient resource recycling and purification treatment method for coating wastewater in the automobile industry. The method comprises the following steps: carrying out filtering and deslagging, pH regulation, coagulating sedimentation and solid-liquid separation on wastewater generated in a coating workshop in the automobile industry; degrading organic matters in the pretreated wastewater by using an activated sludge method or a biofilm method; further removing refractory organic matters, electrophoretic paint and heavy metal ions in the wastewater subjected to biological treatment by adopting a multi-stage membrane separation technology to obtain a high-concentration solvent subjected to membrane separation; the high-concentration solvent subjected to membrane separation is recycled through a resource recycling unit; and the wastewater subjected to resource recycling treatment is disinfected, so that pathogenic microorganisms in the wastewater are killed, and the safety of effluent quality is ensured. The resource recycling and purification treatment method for the automobile coating wastewater can effectively solve the problem of treatment of the coating wastewater in the automobile industry, realizes efficient recycling and high-standard purification of the wastewater, and has a wide application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of water treatment, and in particular relates to a method for efficiently recycling and purifying painting wastewater in the automobile industry. Background Art

[0002] The painting process in the automobile manufacturing process produces a large amount of wastewater containing high concentrations of organic solvents. If these wastewaters are discharged directly without proper treatment, they will cause serious pollution to the environment. Traditional treatment methods such as coagulation and sedimentation, biological treatment, etc. have limitations in treatment efficiency, effluent quality and resource recovery. Therefore, it is particularly important to develop a new technology that can not only efficiently recover organic solvents in wastewater, but also achieve deep purification of wastewater.

[0003] Chinese patent CN111470717A discloses a method for treating and reusing wastewater from electrophoretic coating of new energy vehicles, which includes the following steps: 1) phosphating wastewater treatment; 2) solid-liquid separation of phosphating wastewater; 3) coating wastewater treatment; 4) solid-liquid separation of coating wastewater; 5) wastewater conditioning and quantity adjustment; 6) wastewater hydrolysis and acidification; 7) wastewater contact oxidation; 8) membrane biological reaction; 9) ultraviolet disinfection and discharge; 10) sludge reuse: the sludge entering the production sludge pool, phosphating sludge pool and biochemical sludge pool is concentrated in the first sludge concentration pool, the second sludge concentration pool and the third sludge concentration pool, and the concentrated sludge is sent to the first chamber filter press, the second chamber filter press and the third chamber filter press for filtration. This solution has complex process, long process and high treatment cost.

[0004] Chinese patent CN112624517A discloses a wastewater treatment process for the coating industry, including a coating wastewater treatment process and a comprehensive treatment process, including the following treatment process steps: S1, the wastewater in the coating circulation pool is filtered, the filtrate enters the sedimentation tank, the coating wastewater in the collection tank enters the Fenton oxidation tank, and then undergoes coagulation and sedimentation; S2, the electrophoresis wastewater flows into the comprehensive regulating tank by gravity after sedimentation, and first enters the coagulation and sedimentation tank by pumping; S3, the water in the intermediate water tank is pumped to the biochemical tank to degrade organic matter; S4, the residual sludge generated during the comprehensive wastewater sedimentation process is pumped to the sludge concentration tank, and then dehydrated by the filter press. However, the treatment effect of this process is poor, the effluent quality is not high, and there is no good resource recovery. Summary of the invention

[0005] Existing methods for treating painting wastewater, such as coagulation sedimentation and biological treatment, have problems of low treatment efficiency, poor effluent quality and poor resource recovery. The present invention provides a method for efficient resource recovery and purification of painting wastewater in the automobile industry.

[0006] The solution of this application integrates membrane separation technology, advanced oxidation technology, and bio-enhanced treatment technology. Through the solution provided in this application, effective separation, recovery and high-standard purification of wastewater can be achieved, environmental pollution can be reduced, and resource utilization efficiency can be improved.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] The present invention provides a method for efficiently recycling and purifying painting wastewater in the automobile industry, comprising the following steps:

[0009] (1) Wastewater pretreatment: The wastewater generated by the paint shop of the automobile industry is filtered to remove slag, pH is adjusted, and coagulated and precipitated, and solid-liquid separation is performed to obtain pretreated wastewater;

[0010] (2) Biological treatment: using activated sludge or biofilm method to degrade organic matter in pre-treated wastewater and improve the biodegradability of wastewater;

[0011] (3) Membrane separation: Multi-stage membrane separation technology is used to further remove refractory organic matter, electrophoretic paint and heavy metal ions in the wastewater after biological treatment to obtain a high-concentration solvent after membrane separation;

[0012] (4) Resource recovery: The high-concentration solvent after membrane separation is recovered and reused through the resource recovery unit;

[0013] (5) Disinfection: Disinfection of wastewater after resource recovery to kill pathogenic microorganisms and ensure the safety of effluent water quality.

[0014] In one embodiment of the present invention, the wastewater pretreatment in step (1) specifically comprises the following steps:

[0015] (1.1) Collection: Wastewater generated by the paint shop in the automotive industry first enters the wastewater collection tank for preliminary mixing and homogenization;

[0016] (1.2) Pretreatment: The wastewater passes through a screen to remove large suspended solids, then enters a regulating tank where a pH regulator is added to adjust the water quality and quantity to provide stable conditions for subsequent treatment;

[0017] (1.3) Coagulation and sedimentation: Add coagulants and coagulant aids to the wastewater treated in step (1.2) to condense the suspended solids, colloidal substances and soluble organic matter in the wastewater into larger particles, and achieve solid-liquid separation in a sedimentation tank to obtain pretreated wastewater.

[0018] In one embodiment of the present invention, in step (1.2), the grid gap is ≤5 mm, the retention time in the adjustment tank is ≥4 h, and the pH is adjusted to 6-9.

[0019] In one embodiment of the present invention, in step (1.3), the coagulant is PAC, the coagulant aid is PAM, the concentration of the coagulant after being added to the wastewater is 10-30 mg / L (for example, 20 mg / L), the concentration of the coagulant aid after being added to the wastewater is 0.3-3 mg / L (for example, 0.5 mg / L), and after the coagulant and coagulant aid are added to the wastewater, the sedimentation time is 1 to 2 hours.

[0020] In one embodiment of the present invention, after the coagulation and sedimentation in step (1.3), flotation treatment is also performed, and the flotation treatment method is:

[0021] Use high-efficiency flotation equipment and add demulsifiers to make the tiny oil droplets in the wastewater condense and float, removing most of the floating oil.

[0022] In one embodiment of the present invention, during the flotation treatment, the dissolved air volume is 5% of the wastewater volume, and the flotation time is 0.5 hours.

[0023] In one embodiment of the present invention, the biological treatment in step (2) is specifically: using a sequencing batch sludge process (SBR) or an anaerobic-aerobic (A / O) biological treatment process to utilize the metabolic action of microorganisms to degrade organic matter in the wastewater.

[0024] In one embodiment of the present invention, a sequencing batch sludge (SBR) reactor is used to degrade organic matter using microorganisms through periodic water filling, reaction, sedimentation, and drainage steps.

[0025] In one embodiment of the present invention, an anaerobic-aerobic (A / O) biological treatment process is used to effectively degrade biodegradable organic matter in wastewater, wherein the wastewater first enters an anaerobic tank, where macromolecular organic matter is degraded into small molecular substances under the action of anaerobic bacteria; then enters an aerobic tank, where the organic matter is further degraded into carbon dioxide and water under the action of aerobic bacteria.

[0026] In one embodiment of the present invention, the dissolved oxygen concentration in the aerobic tank is 2-4 mg / L, the hydraulic retention time is ≥12 h, and the dissolved oxygen concentration in the anaerobic tank is less than 0.5 mg / L, the hydraulic retention time is 6 hours.

[0027] In one embodiment of the present invention, the concentration of microbial strains is ≥10^8 CFU / mL.

[0028] In one embodiment of the present invention, the biological treatment in step (2) further comprises the following steps: using a membrane bioreactor (MBR) to perform deep treatment on the wastewater after the sequencing batch activated sludge process (SBR) or the anaerobic-aerobic (A / O) biological treatment process to improve the removal rate of organic matter and suspended solids. MBR technology combines the advantages of biological treatment and membrane separation, and can achieve efficient and stable wastewater treatment.

[0029] In one embodiment of the present invention, the multi-stage membrane separation technology in step (3) specifically includes the following steps: using ultrafiltration membrane or nanofiltration membrane treatment, and then using reverse osmosis membrane to further remove refractory organic matter, electrophoretic paint and heavy metal ions in the wastewater, wherein the pore size of the ultrafiltration membrane (UF membrane) is 0.01-0.1 μm, the desalination rate of the nanofiltration (NF) membrane is ≥90%, the desalination rate of the reverse osmosis membrane (RO membrane) is 99%, the operating pressure is ≤5 MPa, and the recovery rate is ≥70%. Reverse osmosis (RO) is used to further purify the wastewater after MBR treatment and achieve the separation of heavy metal ions and soluble organic matter.

[0030] In one embodiment of the present invention, after the multi-stage membrane separation in step (3), an advanced oxidation treatment is further performed, wherein the advanced oxidation treatment is to use ozone (O3) or Fenton's reagent for deep oxidation to remove refractory organic matter.

[0031] In one embodiment of the present invention, during the advanced oxidation treatment, the amount of O3 added is 10-50 mg / L, and the Fenton reagent Fe 2+ / H2O2 molar ratio 1:5-1:15, reaction time ≥2h.

[0032] In one embodiment of the present invention, the step (5) of disinfecting the wastewater after resource recovery treatment is to use ultraviolet (UV) disinfection or sodium hypochlorite disinfection to kill pathogenic microorganisms in the wastewater to ensure the safety of effluent water quality.

[0033] In one embodiment of the present invention, the sludge generated during the treatment process needs to be dehydrated, dried, etc., and finally be harmlessly disposed of or recycled. :

[0034] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0035] 1. The scheme of this application adopts multi-stage membrane separation technology to achieve efficient separation and recovery of wastewater and improve resource utilization.

[0036] 2. Advanced oxidation and bio-augmentation can be combined: use advanced oxidation technology to treat difficult-to-degrade organic matter, and then use bio-augmentation treatment to further purify the water quality to ensure that the effluent meets the standards.

[0037] 3. Based on the process provided in this application, membrane separation technology can efficiently recover organic solvents in wastewater and reduce resource waste.

[0038] 4. Based on the process provided in this application, the effluent quality is excellent: combining advanced oxidation and bio-augmented treatment to ensure that the effluent quality is better than the national emission standards and is suitable for reuse or discharge.

[0039] 5. Based on the process provided in this application, the operating cost is low: the intelligent control system optimizes the operating parameters, reduces energy consumption and reagent consumption, and reduces operating costs.

[0040] The method for recycling and purifying automobile painting wastewater provided by the present invention can effectively solve the problem of painting wastewater treatment in the automobile industry, realize efficient recycling of wastewater and high-standard purification of wastewater, and has broad application prospects. DETAILED DESCRIPTION

[0041] The present invention is described in detail below with reference to specific embodiments.

[0042] Example 1

[0043] The coating wastewater containing organic solvents of a large automobile parts manufacturer was treated.

[0044] Project Background

[0045] The auto parts manufacturer produces about 1,000 tons of painting wastewater containing organic solvents every day. The main pollutants are organic solvents such as ethanol, toluene, xylene, as well as heavy metal ions, pigments, resins, etc. If the wastewater is discharged directly without treatment, it will cause serious pollution to the environment.

[0046] The process is as follows:

[0047] (1) Wastewater collection: The wastewater generated by the painting workshop first enters the wastewater collection tank for preliminary mixing and homogenization.

[0048] (2) Pretreatment: The wastewater passes through a screen to remove large suspended solids, and then enters a regulating tank for water quality and quantity adjustment to provide stable conditions for subsequent treatment.

[0049] (3) Coagulation and sedimentation: Add coagulants and flocculants to the wastewater to make the suspended matter, colloidal substances and soluble organic matter in the wastewater condense into larger particles, and achieve solid-liquid separation through sedimentation tanks.

[0050] (4) Flotation treatment: Dissolved air flotation is used for wastewater containing a large amount of emulsified oil and difficult-to-precipitate organic matter. The solid-liquid separation is achieved by adhering tiny bubbles to the flocs and causing them to float up.

[0051] (5) Biological treatment: Use activated sludge method or biofilm method to degrade organic matter in wastewater and improve the biodegradability of wastewater.

[0052] (6) Membrane separation: Ultrafiltration and reverse osmosis membrane technology are used to further remove difficult-to-degrade organic matter, electrophoretic paint, and heavy metal ions in wastewater.

[0053] (7) Resource recovery: The high-concentration solvent after membrane separation is recovered and reused through the resource recovery unit.

[0054] (8) Disinfection: Disinfect the treated wastewater to kill pathogenic microorganisms and ensure the safety of the effluent water quality.

[0055] Parameter settings

[0056] Grille: gap is 5mm.

[0057] Adjustment tank: The residence time is 2 hours, and the pH value is controlled between 6-9.

[0058] Coagulation and sedimentation unit: the dosage of coagulant PAC is 20 mg / L, the dosage of coagulant aid PAM is 0.5 mg / L, and the sedimentation time is 1.5 hours.

[0059] Flotation treatment unit: The dissolved air volume is 5% of the wastewater volume, and the flotation time is 0.5 hours.

[0060] Biological treatment unit: The dissolved oxygen concentration in the aerobic tank is 2 mg / L, the dissolved oxygen concentration in the anaerobic tank is less than 0.5 mg / L, and the hydraulic retention time is 6 hours.

[0061] Membrane separation unit: The pore size of the ultrafiltration membrane is 0.01μm, and the desalination rate of the reverse osmosis membrane is 99%.

[0062] Resource recovery unit: recovery efficiency is 80%.

[0063] Disinfection treatment unit: UV disinfection equipment, irradiation intensity is 3000μW / cm 2 , the irradiation time is 15 minutes.

[0064] The processing effect is:

[0065] Outlet water quality: CODCr concentration dropped from 2000mg / L to below 50mg / L, and heavy metal ion concentration was lower than the national emission standard.

[0066] Resource recovery rate: The solvent recovery rate is 82%, and the heavy metal ion recovery rate is 88%.

[0067] Economic benefits: After the implementation of the project, the company can save about 5 million yuan in processing costs each year, while realizing the resource utilization of solvents and heavy metal ions and increasing corporate revenue.

[0068] Example 2

[0069] The coating wastewater containing organic solvents of a certain automobile manufacturing enterprise was treated.

[0070] Project Background

[0071] The paint shop of the automobile manufacturer produces about 800 tons of wastewater every day, which mainly contains pollutants such as electrophoretic paint, organic solvents, grease, heavy metal ions, etc. Wastewater treatment is difficult and requires resource recycling.

[0072] The process is as follows:

[0073] Wastewater Collection and Conditioning

[0074] The wastewater generated by the coating line is collected through pipes into a regulating tank for homogenization adjustment to keep the flow and water quality of the wastewater stable, providing favorable conditions for subsequent treatment.

[0075] In the regulating tank, an appropriate amount of acid-base regulator is added through a dosing device to control the pH value of the wastewater within an appropriate range (6-9) for subsequent biological and chemical treatments.

[0076] Preprocessing

[0077] Screens are used to remove large suspended and floating particles in wastewater to prevent them from clogging subsequent treatment equipment.

[0078] Through coagulation sedimentation and flotation treatment, suspended matter, grease and some soluble organic matter in wastewater are removed. During coagulation sedimentation, coagulants (such as polyaluminium chloride PAC) and coagulants (such as polyacrylamide PAM) are added to the wastewater to form large floccules that are easy to settle through stirring reaction, and then solid-liquid separation is achieved through the sedimentation tank. During flotation treatment, tiny bubbles are used to adhere to oil droplets and suspended matter in the wastewater to make them float, thereby achieving solid-liquid separation.

[0079] Biological treatment

[0080] The sequencing batch activated sludge process (SBR) or anaerobic-aerobic (A / O) biological treatment process is used to utilize the metabolic action of microorganisms to degrade organic matter in wastewater.

[0081] In the SBR reactor, biological treatment of wastewater is achieved through periodic water filling, reaction, precipitation, drainage and other steps. In the A / O process, wastewater first enters the anaerobic tank, where anaerobic bacteria degrade large molecular organic matter into small molecular substances; then it enters the aerobic tank, where aerobic bacteria further degrade organic matter into carbon dioxide and water.

[0082] Membrane separation and resource recovery

[0083] Membrane bioreactor (MBR) technology is used to deeply treat the wastewater after biochemical treatment to improve the removal rate of organic matter and suspended solids. MBR technology combines the advantages of biological treatment and membrane separation, and can achieve efficient and stable wastewater treatment.

[0084] Through the nanofiltration (NF) or reverse osmosis (RO) membrane system, pollutants such as soluble organic matter, heavy metal ions and electrophoretic paint in the wastewater are further removed. At the same time, the high-concentration solvent and electrophoretic paint separated by the membrane are recycled and reused to achieve the recycling of resources.

[0085] Disinfection

[0086] Ultraviolet (UV) disinfection or sodium hypochlorite disinfection are used to kill pathogenic microorganisms in wastewater to ensure the safety of effluent water quality.

[0087] Sludge treatment

[0088] The sludge generated during the treatment process needs to be dehydrated, dried, and ultimately disposed of harmlessly or recycled.

[0089] In this embodiment, the processing parameters are as follows:

[0090] Grille: gap is 5mm.

[0091] Equalization tank: The retention time is 2 hours.

[0092] Coagulation and sedimentation unit: the dosage of coagulant PAC is 20 mg / L, the dosage of coagulant aid PAM is 0.5 mg / L, and the sedimentation time is 1.5 hours.

[0093] Flotation treatment unit: The dissolved air volume is 5% of the wastewater volume, and the flotation time is 0.5 hours.

[0094] Biological treatment unit: The dissolved oxygen concentration in the aerobic tank is 2 mg / L, the dissolved oxygen concentration in the anaerobic tank is less than 0.5 mg / L, and the hydraulic retention time is 6 hours.

[0095] Membrane separation unit: The pore size of the ultrafiltration membrane is 0.01μm, and the desalination rate of the reverse osmosis membrane is 99%.

[0096] Resource recovery unit: recovery efficiency is 80%.

[0097] Disinfection treatment unit: UV disinfection equipment, irradiation intensity is 3000μW / cm 2 The irradiation time is 15 minutes.

[0098] Outlet water quality: CODCr concentration dropped from 1500mg / L to below 30mg / L, heavy metal ion concentration was lower than the national emission standard, and the electrophoretic paint recovery rate reached more than 90%.

[0099] Resource recovery rate: The recovery rate of electrophoretic paint is 92%, and the recovery rate of organic solvent is 78%.

[0100] Economic and environmental benefits: After the implementation of the project, the company can save about 4 million yuan in processing costs each year. At the same time, it realizes the resource utilization of electrophoretic paint and organic solvents, reduces waste emissions, and reduces the impact on the environment.

[0101] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for efficient resource recovery and purification of automobile industry painting wastewater, characterized in that: The following steps are involved: (1) Wastewater pretreatment: The wastewater generated by the paint shop of the automobile industry is filtered to remove slag, pH is adjusted, and coagulated and precipitated, and solid-liquid separation is performed to obtain pretreated wastewater; (2) Biological treatment: using activated sludge or biofilm method to degrade organic matter in pre-treated wastewater; (3) Membrane separation: Multi-stage membrane separation technology is used to further remove refractory organic matter, electrophoretic paint and heavy metal ions in the wastewater after biological treatment to obtain a high-concentration solvent after membrane separation; (4) Resource recovery: The high-concentration solvent after membrane separation is recovered and reused through the resource recovery unit; (5) Disinfection: Disinfection of wastewater after resource recovery to kill pathogenic microorganisms and ensure the safety of effluent water quality.

2. According to claim 1, a method for efficient resource recovery and purification of automobile industry painting wastewater is characterized in that: The wastewater pretreatment in step (1) specifically comprises the following steps: (1.1) Collection: Wastewater generated by the paint shop in the automotive industry first enters the wastewater collection tank for preliminary mixing and homogenization; (1.2) Pretreatment: The wastewater passes through a screen to remove large suspended solids, and then enters a regulating tank where a pH regulator is added to adjust the water quality and quantity; (1.3) Coagulation and sedimentation: Add coagulants and coagulant aids to the wastewater treated in step (1.2) to condense the suspended solids, colloidal substances and soluble organic matter in the wastewater into larger particles, and achieve solid-liquid separation in a sedimentation tank to obtain pretreated wastewater.

3. According to claim 2, a method for efficient resource recovery and purification of automobile industry painting wastewater is characterized in that: In step (1.2), the grid gap is ≤5 mm, the retention time in the regulating tank is ≥4 h, and the pH is adjusted to 6-9; In step (1.3), the coagulant is PAC, the coagulant aid is PAM, the concentration of the coagulant after being added to the wastewater is 10-30 mg / L, the concentration of the coagulant aid after being added to the wastewater is 0.3-3 mg / L, and the sedimentation time after the coagulant and coagulant aid are added to the wastewater is 1 to 2 hours.

4. According to claim 3, a method for efficient resource recovery and purification of automobile industry painting wastewater is characterized in that: After the coagulation and sedimentation in step (1.3), flotation treatment is also performed, and the flotation treatment method is: Use high-efficiency flotation equipment to add demulsifiers to make the tiny oil droplets in the wastewater condense and float, removing most of the floating oil; When flotation treatment is carried out, the dissolved air volume is 5% of the wastewater volume and the flotation time is 0.5 hours.

5. According to claim 1, a method for efficient resource recovery and purification of automobile industry painting wastewater is characterized in that: The biological treatment in step (2) specifically comprises: using a sequencing batch activated sludge process or an anaerobic-aerobic biological treatment process to utilize the metabolic action of microorganisms to degrade organic matter in the wastewater; When the anaerobic-aerobic biological treatment process is adopted, the wastewater first enters the anaerobic tank, where the macromolecular organic matter is degraded into small molecular substances under the action of anaerobic bacteria; then it enters the aerobic tank, where the organic matter is further degraded into carbon dioxide and water under the action of aerobic bacteria; the dissolved oxygen concentration in the aerobic tank is 2-4 mg / L, and the hydraulic retention time is ≥12h; the dissolved oxygen concentration in the anaerobic tank is less than 0.5 mg / L, and the hydraulic retention time is 6 hours; Microbial strain concentration ≥10^8CFU / mL.

6. The method for efficient resource recovery and purification of automobile industry painting wastewater according to claim 5 is characterized in that: The biological treatment in step (2) further comprises the following steps: using a membrane bioreactor to deeply treat the wastewater after the sequencing batch activated sludge process or the anaerobic-aerobic biological treatment process to improve the removal rate of organic matter and suspended solids.

7. The method for efficient resource recovery and purification of automobile industry painting wastewater according to claim 1 is characterized in that: The multi-stage membrane separation technology in step (3) specifically includes the following steps: using ultrafiltration membrane or nanofiltration membrane treatment, and then using reverse osmosis membrane to further remove refractory organic matter, electrophoretic paint and heavy metal ions in the wastewater, wherein the pore size of the ultrafiltration membrane is 0.01-0.1 μm, the nanofiltration membrane desalination rate is ≥90%, the reverse osmosis membrane desalination rate is 99%, the operating pressure is ≤5 MPa, and the recovery rate is ≥70%.

8. The method for efficient resource recovery and purification of automobile industry painting wastewater according to claim 7 is characterized in that: After the multi-stage membrane separation in step (3), an advanced oxidation treatment is further performed, wherein the advanced oxidation treatment is deep oxidation using ozone or Fenton's reagent to remove refractory organic matter; In advanced oxidation treatment, the O3 dosage is 10-50 mg / L, and the Fenton reagent Fe 2+ / H2O2 molar ratio 1:5-1:15, reaction time ≥2h.

9. The method for efficient resource recovery and purification of automobile industry painting wastewater according to claim 1 is characterized in that: In step (5), the wastewater after resource recovery treatment is disinfected by using ultraviolet disinfection or sodium hypochlorite disinfection to kill pathogenic microorganisms in the wastewater and ensure the safety of the effluent water quality.

10. The method for efficient resource recovery and purification of automobile industry painting wastewater according to claim 1 is characterized in that: The sludge generated during the treatment process needs to be dehydrated, dried, and ultimately disposed of harmlessly or recycled.