A treatment device and treatment process for coating electrophoresis wastewater

Abstract

The present invention discloses a treatment device and treatment process for painting electrocoating wastewater, belonging to the technical field of wastewater treatment. The treatment device includes a physicochemical reaction device, and the physicochemical reaction device includes a first physicochemical reaction tank, a second physicochemical reaction tank, a third physicochemical reaction tank, and a fourth physicochemical reaction tank connected in series in sequence; reactant chemical dosing points are provided in each physicochemical reaction tank; reactant chemicals can be added to different physicochemical reaction tanks through each dosing point. When treating the painting electrocoating wastewater in this treatment device, the dosing sequence of each reactant chemical is polyaluminum chloride (PAC), Ca(OH)2 added once, Ca(OH)2 added a second time, NaOH, polyacrylamide (PAM), and Ca(OH)2 is added in two portions, which can significantly improve the treatment effect, reduce the usage amount of reactant chemicals, and reduce the treatment cost.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment, and in particular relates to a treatment device and a treatment process for coating electrophoresis wastewater. Background Art

[0002] Painting wastewater is widely generated in various manufacturing production processes such as machinery manufacturing and precision machining. Take the automobile industry as an example: the painting of the inner and outer surfaces of the automobile body is the link that generates and discharges the most wastewater during the four major processes of automobile production in the vehicle factory. With the vigorous development of the domestic automobile industry, the discharge of automobile painting wastewater has increased significantly, and the impact on our living environment is becoming increasingly serious. Automobile painting wastewater is the focus and difficulty of pollution control in the industry. The wastewater discharged from automobile painting has the characteristics of many types, large changes in discharge volume, complex components, and unstable discharge concentration. Among the wastewater in the painting workshop, the electrophoretic wastewater has the highest degree of pollution.

[0003] Electrophoretic wastewater mainly comes from electrophoretic paint-containing wastewater from tank cleaning, car body cleaning, skid cleaning, etc. in the electrophoretic area of ​​the paint shop, as well as paint-containing wastewater discharged from electrophoretic tank tank inversion, electrophoretic paint leakage, etc. The characteristics of this wastewater are: high COD, high SS, and low biodegradability. It is the most difficult wastewater to treat in the entire paint shop, and it is the key to the success of the entire plant wastewater treatment process. It is also the part with the highest operating cost in the later operation and management of the entire plant wastewater treatment station. Therefore, the pursuit of electrophoretic wastewater pretreatment technology with better treatment effect, lower operating cost, and smaller footprint is a hot topic in the current research on wastewater treatment in paint shops of vehicle manufacturers at home and abroad, and it is also the key to solving water pollution in the automotive industry.

[0004] In the Chinese invention patent application CN105417840A (a method for treating wastewater before painting), the wastewater is first degreased, and then added to a regulating tank for coagulation reaction. During the coagulation reaction, Ca(OH) 2, and treated at a pH of 10-11. The coagulated wastewater is added to the inclined plate sedimentation tank for solid-liquid separation, and then the solid suspended matter in the wastewater is removed by the filter. The filter uses a quartz sand filter and is equipped with a backwash system: the backwash effluent is returned to the regulating tank, and the quartz sand filter effluent is adjusted by a static mixer and then enters the clean water tank. This method uses the traditional coagulation and sedimentation method to remove pollutants. It is an extensive process with too high a treatment cost and is not suitable for scenes with high environmental protection requirements. In Chinese invention patent application CN107265787A (Automobile painting wastewater treatment process and automobile painting wastewater treatment system), automobile painting wastewater is treated by pretreatment, coagulation reaction, precipitation removal, hydrolysis acidification and molecular decomposition. The pretreatment process can degrease and precipitate the wastewater; then the pretreated wastewater is coagulated with an alkalizer, and the precipitate is removed. The hydrolysis acidification step can convert high-molecular organic matter into small-molecular organic matter. Finally, the hydrolyzed and acidified wastewater is added to a biological filter tank, and the small-molecular organic matter is decomposed by a biodegradation method. This treatment method relies on the decomposition of microorganisms, and different microorganisms can decompose different types of small-molecular organic matter, which may cause some components to fail to be effectively degraded.

[0005] In the Chinese invention patent application CN103319057A (a small integrated treatment device for coating wastewater), the treatment device includes a raw water pipeline pump, an upflow neutralization tower, an alkali doser, an acid doser, a polyacrylamide (PAM) doser, and a polyaluminium chloride (PAC) doser. The device is provided with a plurality of upflow neutralization towers, each of which is connected to the raw water pipe via a branch pipe with an adjustable rotor flowmeter. A pH detector is provided at the outlet of the upflow neutralization tower, and a magnetic pump is provided at the outlet of the alkali doser, acid doser, PAM doser, and PAC doser. In the device, all equipment is uniformly installed on a skid, centrally controlled by a PLC electric control cabinet, and occupies a small area. However, the device is not suitable for flow rates of 1-3m 3 The treatment effect of coating wastewater is good when the flow rate is small, but the treatment effect is poor when the flow rate is large.

[0006] Among the existing electrophoresis wastewater pretreatment processes, the most typical one in actual industrial application is "physical-chemical reaction + precipitation". The most common physico-chemical reaction is mainly a four-stage reaction. In each stage of the reaction tank, Ca(OH) 2 (controlled by pH value), NaOH (controlled by pH value), PAC, PAM, the design value of residence time at each level is 20-30min. The obvious shortcomings of this process are: 1. Ca(OH) 2 1. The dosage of the drug is large, the dosage is greater than 300ppm; 2. The dosage of PAC is large, the dosage is greater than 150ppm; 3. The amount of physical and chemical sludge produced is large; 4. The pipeline is easily clogged. Summary of the invention

[0007] The problem to be solved by the present invention is that in the prior art, in the process of treating coating electrophoresis wastewater, there are technical problems such as poor treatment effect, large dosage of chemicals, large amount of sludge produced, and easy clogging of pipelines.

[0008] In order to solve the above technical problems, the present invention discloses a treatment process for coating electrophoresis wastewater, comprising the following steps:

[0009] (1) Add the coating electrophoresis wastewater into the first physicochemical reaction tank, add polyaluminium chloride into the first physicochemical reaction tank, and react 1 After a certain time, the coating electrophoresis wastewater is added into the second physicochemical reaction tank;

[0010] (2) Adding Ca(OH) to the second physicochemical reaction tank 2 , reaction t 2 After a certain time, the coating electrophoresis wastewater is added into the third physicochemical reaction tank;

[0011] (3) Add Ca(OH) to the third physicochemical reaction tank 2 and NaOH, reaction t 3 After a certain time, the coating electrophoresis wastewater is added into the fourth physicochemical reaction tank;

[0012] (4) Add polyacrylamide to the fourth physicochemical reaction tank, and react 4 After a period of time, the coating electrophoresis wastewater treated by physicochemical reaction is discharged.

[0013] Furthermore, in the treatment process, the pH in the second physicochemical reaction tank is adjusted to 8-10, and the pH in the third physicochemical reaction tank is adjusted to 10-11.

[0014] The present invention also claims protection for a coating electrophoresis wastewater treatment device for treating coating electrophoresis wastewater, the device comprising a physicochemical reaction device, the physicochemical reaction device comprising a physicochemical reaction tank, the physicochemical reaction tank comprising a first physicochemical reaction tank, a second physicochemical reaction tank, a third physicochemical reaction tank, and a fourth physicochemical reaction tank connected in series in sequence;

[0015] The first physicochemical reaction tank is provided with a water inlet;

[0016] Every two adjacent physicochemical reaction tanks are connected via a water outlet;

[0017] The fourth physicochemical reaction tank is provided with a water outlet;

[0018] The first physicochemical reaction tank is provided with a PAC dosing point; the second physicochemical reaction tank is provided with a Ca(OH) 2 The first dosing point; the third physicochemical reaction tank is equipped with Ca(OH) 2Secondary dosing point and NaOH dosing point; the fourth physicochemical reaction tank is provided with a PAM dosing point; the second physicochemical reaction tank and the third physicochemical reaction tank are both provided with a pH meter;

[0019] The PAC dosing point is connected to a PAC storage tank via a PAC dosing pump; the Ca(OH) 2 Primary dosing point, Ca(OH) 2 The secondary dosing points are respectively through Ca(OH) 2 Primary dosing pump, Ca(OH) 2 The secondary dosing pump is connected to Ca(OH) 2 The NaOH dosing point is connected to the NaOH storage barrel via a NaOH dosing pump; the PAM dosing point is connected to the PAM storage barrel via a PAM dosing pump. A stirrer is provided in each storage barrel for dissolving and stirring the reagents in each storage barrel.

[0020] Furthermore, the volume of the physicochemical reaction tank is determined by the following formula: V n =C·t n ;

[0021] Where n = 1, 2, 3, 4, V n is the volume of each physicochemical reaction tank, C is the inlet flow rate of the coating electrophoresis wastewater entering the physicochemical reaction device, t n It is the reaction time of coating electrophoresis wastewater in each physicochemical reaction tank.

[0022] Here, t n It is set in advance according to the specific physicochemical reaction process. Specifically, the reaction times in the first to fourth physicochemical reaction tanks are: t 1 ≧12min, t 2 ≧16min, t 3 ≧16min, t 4 ≧16min. This time can be set according to the specific application scenario.

[0023] Furthermore, the water inlet is located at the top of the side of the first physicochemical reaction tank; the water outlet is located at the top of the side of the fourth physicochemical reaction tank. Furthermore, the first physicochemical reaction tank and the second physicochemical reaction tank are connected through a first water outlet, the second physicochemical reaction tank and the third physicochemical reaction tank are connected through a second water outlet, and the third physicochemical reaction tank and the fourth physicochemical reaction tank are connected through a third water outlet; every two adjacent physicochemical reaction tanks share a side wall;

[0024] The first water outlet is located at the bottom of the common side wall of the first physicochemical reaction tank and the second physicochemical reaction tank, on a side away from the water inlet; the second water outlet is located at the top of the common side wall of the second physicochemical reaction tank and the third physicochemical reaction tank, on a side away from the first water outlet; the third water outlet is located at the bottom of the common side wall of the third physicochemical reaction tank and the fourth physicochemical reaction tank, on a side away from the second water outlet.

[0025] Under such setting conditions, the pre-treated coating electrophoresis wastewater flows the longest distance after entering the physicochemical reaction tank, and the physicochemical reaction can be carried out more thoroughly.

[0026] Furthermore, a stirrer is installed in the physicochemical reaction tank, and the coating electrophoresis wastewater and the reagent can be fully mixed and reacted through the stirring of the stirrer.

[0027] Furthermore, the PAC dosing point is located at the water inlet; the PAC dosing point is located inside the first physicochemical reaction tank and adjacent to the water inlet; the Ca(OH) 2 The primary dosing point is located inside the second physicochemical reaction tank and adjacent to the first water outlet; the Ca(OH) 2 The secondary dosing point and NaOH dosing point are located inside the third physicochemical reaction tank, and Ca(OH) 2 The secondary dosing point is adjacent to the second water outlet, and the NaOH dosing point is adjacent to the Ca(OH) 2 The secondary dosing point is adjacent; the PAM dosing point is located inside the fourth physicochemical reaction tank and is adjacent to the third water outlet.

[0028] Furthermore, the probe of the pH meter in the second physicochemical reaction tank is located at a diagonal position opposite to the first water outlet; the probe of the pH meter in the third physicochemical reaction tank is located at a diagonal position opposite to the second water outlet.

[0029] The treatment process for treating coating electrophoresis wastewater using the above-mentioned treatment device comprises the following steps:

[0030] (1) The coating electrophoresis wastewater enters the first physicochemical reaction tank from the water inlet;

[0031] (2) PAC is added to the first physicochemical reaction tank through the PAC dosing point, and the reaction time is t 1 After a certain time, the coating electrophoresis wastewater enters the second physicochemical reaction tank through the first water outlet;

[0032] (3) Through Ca(OH) 2 The first dosing point adds Ca(OH) to the second physicochemical reaction tank. 2 , reaction t 2 After a certain time, the coating electrophoresis wastewater enters the third physicochemical reaction tank through the second water outlet;

[0033] (4) Through Ca(OH) 2 The secondary dosing point and the NaOH dosing point add Ca(OH) to the third physicochemical reaction tank. 2 and NaOH, reaction t 3 After a certain time, the coating electrophoresis wastewater enters the fourth physicochemical reaction tank through the third water outlet;

[0034] (5) Add PAM to the fourth physicochemical reaction tank through the PAM dosing point, and the reaction time is t 4 After a period of time, the coating electrophoresis wastewater treated by physicochemical reaction is discharged through the outlet.

[0035] Furthermore, in the above treatment process, the pH in the second physicochemical reaction tank is adjusted to 9-10, and the pH in the third physicochemical reaction tank is adjusted to 10-11.

[0036] When the device is in normal use, a pretreatment device is connected in series before the first physicochemical reaction tank, and the pretreated coating electrophoresis wastewater enters the physicochemical reaction device for physicochemical reaction treatment. A sedimentation tank or membrane system is connected in series after the fourth physicochemical reaction tank, and the wastewater after the physicochemical reaction treatment enters the sedimentation tank or membrane system for mud-water separation.

[0037] In the treatment device and treatment process, each section is controlled by a PLC automatic control program, and can be automatically and continuously treated, specifically: (1) when the pre-treated coating electrophoresis wastewater enters the first physicochemical reaction tank, the physicochemical mixer in the first physicochemical reaction tank is automatically turned on, and PAC enters the first physicochemical reaction tank from the PAC storage tank through the PAC dosing point under the action of the PAC dosing pump, and the concentration of PAC in the first physicochemical reaction tank is controlled to be 100-140ppm; (2) then the coating electrophoresis wastewater enters the second physicochemical reaction tank, and the physicochemical mixer in the second physicochemical reaction tank is automatically turned on, Ca(OH) 2 In Ca(OH) 2 Under the action of the primary dosing pump, Ca(OH) 2 The medicine storage tank is passed through Ca(OH) 2 The first dosing point enters the second physicochemical reaction tank, and the pH in the first physicochemical reaction tank is controlled between 8-10, specifically between 9-10; (3) the coating electrophoresis wastewater enters the third physicochemical reaction tank, and the physicochemical mixer in the third physicochemical reaction tank is automatically turned on, Ca(OH) 2 In Ca(OH) 2 Under the action of the secondary dosing pump, Ca(OH) 2 The medicine storage tank is passed through Ca(OH) 2 The secondary dosing point enters the third physicochemical reaction tank to control Ca(OH) 2The concentration in the third physicochemical reaction tank is 40-70ppm, specifically 50-70ppm; NaOH enters the third physicochemical reaction tank from the NaOH storage tank through the NaOH dosing point under the action of the NaOH dosing pump, and the pH in the third physicochemical reaction tank is controlled between 10-11; (4) the coating electrophoresis wastewater enters the fourth physicochemical reaction tank, and the physicochemical mixer in the fourth physicochemical reaction tank is automatically turned on, and PAM enters the fourth physicochemical reaction tank from the PAM storage tank through the PAM dosing point under the action of the PAM dosing pump, and the concentration of PAM in the fourth physicochemical reaction tank is controlled to be 20-40ppm.

[0038] In this treatment process, the order of adding reactants is PAC, Ca(OH) 2 , second addition of Ca(OH) 2 , NaOH and PAM, firstly, under the action of PAC, the coating electrophoresis wastewater flocculates to form flocs; then, Ca(OH) 2 Under the action of Ca(OH) 2 It can also promote further flocculation of wastewater; then add Ca(OH) 2 , and NaOH is added at the same time to adjust the pH of the system; finally, PAM is added for further flocculation to remove most of the suspended matter in the wastewater, and then the wastewater after the physicochemical reaction enters the sedimentation tank for sedimentation and slag removal treatment.

[0039] This dosing sequence can give full play to the "compressed double layer" effect in the colloidal flocculation process and the "netting-bridging" effect of PAC and PAM, and the treatment effect is better; due to the high price of PAC, Ca(OH) is added twice 2 It can reduce the dosage of PAC and reduce the cost in the treatment process. The reduction of dosage can further reduce the generation of sediment, reduce the amount of sludge generated in the system, and greatly reduce the probability of pipeline blockage in the treatment device.

[0040] In the present invention, two adjacent water outlets in the physicochemical reaction tank are staggered, so that the pretreated coating electrophoresis wastewater can enter different physicochemical reaction tanks by cross-flow, which can ensure the physicochemical reaction time of the coating electrophoresis wastewater entering the physicochemical reaction tank in different time periods, and ensure the physicochemical reaction treatment effect and stability of the coating electrophoresis wastewater on the basis of automated and continuous treatment.

[0041] The coating electrophoresis wastewater treatment device and treatment process of the present invention have the following advantages over the prior art:

[0042] (1) In the physicochemical reaction device, different reactant dosing points are set in each physicochemical reaction tank, and Ca(OH) 2 The primary dosing point and the secondary dosing point can realize the treatment process more conveniently and achieve better treatment effect.

[0043] (2) The amount of reactant added is greatly reduced, which reduces the amount of sludge generated in the treatment device and the chance of pipeline blockage.

[0044] (3) The volume of the corresponding physicochemical reaction tank is set according to the inlet flow rate of the wastewater and the physicochemical reaction time, so that the physicochemical reaction of each step is more targeted, and the entire treatment process can operate continuously and stably, thereby improving the treatment effect and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 : Schematic diagram of the flow direction of wastewater in the treatment device for coating electrophoresis wastewater.

[0046] Figure 2 : Schematic diagram of the structure of the physicochemical reaction device and sedimentation tank in the treatment device for coating electrophoresis wastewater.

[0047] Description of reference numerals: 1-physicochemical reaction device, 2-precipitation tank, 3-PAC storage tank, 4-Ca(OH) 2 Drug storage barrel, 5-NaOH drug storage barrel, 6-PAM drug storage barrel, 11-first physicochemical reaction tank, 12-second physicochemical reaction tank, 13-third physicochemical reaction tank 13, 14-fourth physicochemical reaction tank, 15-water inlet, 16-water outlet, 111-first water outlet, 121-second water outlet, 131-third water outlet, 112-PAC dosing point, 122-Ca(OH) 2 One dosing point, 132-Ca(OH) 2 Secondary dosing point, 133-NaOH dosing point, 142-PAM dosing point, 124-pH meter in the second physicochemical reaction tank, 134-pH meter in the third physicochemical reaction tank. DETAILED DESCRIPTION

[0048] The technical solution of the present invention is described in detail below through specific embodiments.

[0049] Generally speaking, the automobile painting process includes degreasing, phosphating, electrophoresis, topcoat and other steps. Electrophoresis wastewater is mainly produced in the workpiece electrophoresis and topcoat stages. The wastewater contains electrophoretic paint (such as water-soluble epoxy resin, ethanolamine, acetonitrile, phenolic resin, etc.), pigments (such as carbon black, red iron oxide, lead and mercury, etc.), fillers (such as titanium dioxide, talcum powder, etc.), organic solvents (such as triethanolamine, butanol, etc.) and a small amount of metal ions. The content of organic pollutants is large and the composition is complex.

[0050] like Figure 1 As shown, a schematic diagram of the flow direction of wastewater in the treatment device of coating electrophoresis wastewater is given. The wastewater first enters the pretreatment device for degreasing and filtering treatment, then enters the physicochemical reaction device 1 for physicochemical reaction treatment, and finally enters the sedimentation tank 2 for sedimentation treatment. The sedimentation can be removed, and the water out of the sedimentation tank is purified water. Among them, the pretreatment device and the sedimentation device 2 both use conventional mechanical equipment in the field.

[0051] like Figure 2 As shown, the structure of the physicochemical reaction device 1 and the sedimentation tank 2 in the treatment device for coating electrophoresis wastewater is given, and a pretreatment device is also arranged in series upstream of the physicochemical reaction device 1. The physicochemical reaction device 1 includes a physicochemical reaction tank, and the physicochemical reaction tank includes a first physicochemical reaction tank 11, a second physicochemical reaction tank 12, a third physicochemical reaction tank 13, and a fourth physicochemical reaction tank 14 connected in series in sequence;

[0052] A water inlet 15 is provided on the top of the side of the first physicochemical reaction tank 11, and the water inlet 15 is connected to the water outlet of the pretreatment device; a water outlet 16 is provided on the top of the side of the fourth physicochemical reaction tank 14; the water outlet 16 is connected to the water inlet of the sedimentation tank 2;

[0053] Every two adjacent physicochemical reaction pools are connected through a water outlet; the first physicochemical reaction pool 11 and the second physicochemical reaction pool 12 are connected through a first water outlet 111, the second physicochemical reaction pool 12 and the third physicochemical reaction pool 13 are connected through a second water outlet 121, and the third physicochemical reaction pool 13 and the fourth physicochemical reaction pool 14 are connected through a third water outlet 131; every two adjacent physicochemical reaction pools share a side wall.

[0054] Among them, the first water outlet 111 is located at the bottom of the common side wall of the first physicochemical reaction tank 11 and the second physicochemical reaction tank 12, on a side away from the water inlet 15; the second water outlet 121 is located at the top of the common side wall of the second physicochemical reaction tank 12 and the third physicochemical reaction tank 13, on a side away from the first water outlet 111; the third water outlet 131 is located at the bottom of the common side wall of the third physicochemical reaction tank 13 and the fourth physicochemical reaction tank 14, on a side away from the second water outlet 121.

[0055] The first physicochemical reaction tank 11 is provided with a PAC dosing point 112; the second physicochemical reaction tank 12 is provided with a Ca(OH) 2 The first dosing point 122; the third physicochemical reaction tank 13 is provided with Ca(OH) 2 The secondary dosing point 132 and the NaOH dosing point 133; the fourth physicochemical reaction tank 14 is provided with a PAM dosing point 142; wherein the PAC dosing point 112 is located inside the first physicochemical reaction tank 11 and adjacent to the water inlet; the Ca(OH) 2The primary dosing point 122 is located inside the second physicochemical reaction tank 12 and adjacent to the first water outlet 111; the Ca(OH) 2 The secondary dosing point 132 and the NaOH dosing point 133 are located inside the third physicochemical reaction tank 13, and Ca(OH) 2 The secondary dosing point 132 is adjacent to the second water outlet 121, and the NaOH dosing point 133 is adjacent to the Ca(OH) 2 The secondary dosing point 132 is adjacent; the PAM dosing point 142 is located inside the fourth physicochemical reaction tank 14 and adjacent to the third water outlet 131 .

[0056] A pH meter 124 is provided in the second physicochemical reaction tank 12, and a pH meter 134 is provided in the third physicochemical reaction tank 13. The probe of the pH meter 124 in the second physicochemical reaction tank 12 is located at a diagonal position opposite to the first water outlet 111; the probe of the pH meter 134 in the third physicochemical reaction tank 13 is located at a diagonal position opposite to the second water outlet 121.

[0057] The PAC dosing point 112 is connected to the PAC storage tank 3 through a PAC dosing pump; the Ca(OH)2 primary dosing point 122 and the Ca(OH)2 secondary dosing point 132 are connected to the Ca(OH)2 storage tank 4 through the Ca(OH)2 primary dosing pump and the Ca(OH)2 secondary dosing pump respectively; the NaOH dosing point 133 is connected to the NaOH storage tank 5 through a NaOH dosing pump; the PAM dosing point 142 is connected to the PAM storage tank 6 through a PAM dosing pump.

[0058] A stirrer is installed in each physicochemical reaction tank to mix the coating electrophoresis wastewater and the reactant reagents evenly and then react; a stirrer is also installed in the reactant storage barrel to dissolve the reagents in each storage barrel for use.

[0059] The treatment process of using the treatment device to treat coating electrophoresis wastewater includes the following steps:

[0060] (1) After being pretreated by the pretreatment device, the coating electrophoresis wastewater enters the first physicochemical reaction tank 11 through the water inlet 15; (2) PAC is added to the first physicochemical reaction tank 11 through the PAC dosing point 112, and the PAC dosing amount is 100-140ppm, and the residence time in the tank is 12min; after the reaction is completed, the coating electrophoresis wastewater enters the second physicochemical reaction tank 12 through the first water inlet 111;

[0061] (3) Through Ca(OH) 2 The primary dosing point 122 adds Ca(OH) to the second physicochemical reaction tank 12. 2The pH value measured by the pH meter 124 controls the start and stop of the dosing, and the pH value is controlled at 9-10. The residence time of the pool is 16 minutes. After the reaction is completed, the coating electrophoresis wastewater enters the third physicochemical reaction pool 13 through the second water outlet 121;

[0062] (4) Through Ca(OH) 2 The secondary dosing point 132 and the NaOH dosing point 133 add Ca(OH) to the third physicochemical reaction tank 13. 2 and NaOH, Ca(OH) 2 The addition amount is 50-70ppm; the start and stop of the dosing is controlled by the pH value measured by the pH meter 134, the pH value is controlled at 10-11, and the residence time of the pool is 16min; after the reaction is completed, the coating electrophoresis wastewater enters the fourth physicochemical reaction pool 14 through the third water outlet 131;

[0063] (5) Anionic PAM is added to the fourth physicochemical reaction tank 14 through the PAM dosing point 142, and the addition amount is 10-25 ppm. The residence time of the tank is 16 minutes. After the reaction is completed, the coating electrophoresis wastewater treated by the physicochemical reaction enters the sedimentation tank 2 through the outlet 16.

[0064] After sedimentation, the water discharged from the sedimentation tank is purified water.

[0065] Example 1: The electrophoresis wastewater from the automobile painting workshop is treated with the treatment device and treatment process of the present invention. The inlet flow rate of the electrophoresis wastewater is 12.5m 3 / h, using the formula V n =C·t n , the volume of each physicochemical reaction pool is obtained as:

[0066] The first physicochemical reaction tank V 1 =12.5*12 / 60=2.5m 3 ;

[0067] The second physicochemical reaction tank V 2 =12.5*16 / 60=3.33m 3 ;

[0068] The third physicochemical reaction tank V 3 =12.5*16 / 60=3.33m 3 ;

[0069] Fourth physical and chemical reaction tank V 4 =12.5*16 / 60=3.33m 3 .

[0070] At the same time, in order to reflect the feasibility and advantages of the coating electrophoresis wastewater treatment device and the treatment process of wastewater treatment using the treatment device in the present invention, two comparative examples are designed at the same time:

[0071] Comparative Example 1: The treatment device of the present invention is used to treat wastewater, which is different from Example 1 in that: in the treatment process, Ca(OH) 2 Without adding in batches, all the Ca(OH) 2 Add all at once, and only add NaOH to the third physicochemical reaction tank.

[0072] Comparative Example 2: Instead of using the treatment device of the present invention, a conventional coating electrophoresis wastewater treatment device and treatment process are used, that is, the order of adding chemicals is: first add Ca(OH) 2 , then add NaOH, and then add PAC, and PAM in sequence. In each stage of the reaction, the residence reaction time is 20-30min.

[0073] Table 1 shows the water quality parameters before and after the treatment of coating electrophoresis wastewater in the above-mentioned Example 1, Comparative Examples 1 and 2 during the project test phase; Table 2 shows the dosage of the reaction reagents during the treatment process.

[0074] Table 1 Water quality parameters of coating electrophoresis wastewater before and after treatment

[0075]

[0076] Table 2 Comparison of the amount of reactants used

[0077]

[0078] Implementation case: In order to verify the industrial use effect of the treatment device of the present invention, in the EPC project of the wastewater treatment system of FAW-Volkswagen Automotive Co., Ltd. Tianjin Factory, the electrophoresis wastewater was treated with the treatment device and treatment process of the present invention. The designed water volume of the electrophoresis wastewater was 25t / h, which is equivalent to 25m 3 / h.

[0079] Use the formula V n =C·t n , the volume of each physicochemical reaction pool is obtained as follows:

[0080] The first physicochemical reaction tank V 1 =25*12 / 60=5m 3 ;

[0081] The second physicochemical reaction tank V 2 =25*16 / 60=6.67m 3 ;

[0082] The third physicochemical reaction tank V3 =25*16 / 60=6.67m 3 ;

[0083] Fourth physical and chemical reaction tank V 4 =25*16 / 60=6.67m 3 .

[0084] The average data of the stable operation of the wastewater station for 6 months (July 2018-January 2019) after the project was put into mass production are shown in Table 3 below.

[0085] Table 3 Average data after mass production using the processing device and processing process of the present invention

[0086]

[0087] When using traditional technology for treatment, the order of adding drugs in the traditional treatment process is: first add Ca(OH) 2 , then add NaOH, then add PAC, and then PAM. In the same treatment process, the amount of PAC used is 210ppm, Ca(OH) 2 The usage of Ca(OH) is 310ppm, and the usage of PAM is 50ppm. Compared with the treatment process of the present invention, the usage of PAC in the treatment process of the present invention is reduced by 42.86%; Ca(OH) 2 The usage of was reduced by 41.93%, and the usage of PAM was reduced by 70%.

[0088] According to the above data, it can be seen that the treatment device of the present invention and the treatment process using the device have good treatment effect in actual application, and the dosage is significantly reduced, achieving a good process operation effect.

[0089] The above description is only a preferred embodiment of the present invention and is not intended to limit the invention. Any modifications, equivalent substitutions, improvements, etc. made within the design concept of the present invention should be included in the protection scope of the present invention.

Claims

1. A treatment process for coating electrophoresis wastewater, Features: The steps include: (1) Add the painted electrophoretic wastewater into the first physicochemical reaction tank, add polyaluminum chloride to the first physicochemical reaction tank, and after reacting for t 1 time, add the painted electrophoretic wastewater into the second physicochemical reaction tank; (2) Add Ca(OH) to the second physicochemical reaction tank 2 , pH value is controlled at 9-10, reaction t 2 After a certain time, the coating electrophoresis wastewater is added into the third physicochemical reaction tank; (3) Add Ca(OH) to the third physicochemical reaction tank 2 and NaOH, pH value is controlled at 10-11, Ca(OH) 2 The addition amount is 50-70ppm, the reaction t 3 After a certain time, the coating electrophoresis wastewater is added into the fourth physicochemical reaction tank; (4) Add polyacrylamide to the fourth physicochemical reaction tank, and the reaction 4 After a period of time, the coating electrophoresis wastewater treated by physicochemical reaction is discharged.

2. The coating electrophoresis wastewater treatment process according to claim 1, Features: The 1 ≧12min, t 2 ≧16min, t 3 ≧16min, t 4 ≧16min.

3. The treatment process for coating electrophoresis wastewater according to claim 1, Features: During the treatment process, the pH in the second physicochemical reaction tank is adjusted to 8-10, and the pH in the third physicochemical reaction tank is adjusted to 10-11.

4. A coating electrophoresis wastewater treatment device, used to implement the coating electrophoresis wastewater treatment process according to any one of claims 1 to 3, comprising a physicochemical reaction device, Features: The physicochemical reaction device includes a physicochemical reaction pool, which includes a first physicochemical reaction pool, a second physicochemical reaction pool, a third physicochemical reaction pool, and a fourth physicochemical reaction pool connected in series in sequence; The first physicochemical reaction tank is provided with a water inlet; Every two adjacent physicochemical reaction tanks are connected via a water outlet; The fourth physicochemical reaction tank is provided with a water outlet; The first physicochemical reaction tank is provided with a polyaluminium chloride dosing point; the second physicochemical reaction tank is provided with a Ca(OH) 2 The first dosing point; the third physicochemical reaction tank is equipped with Ca(OH) 2 A secondary dosing point and a NaOH dosing point; a polyacrylamide dosing point is provided in the fourth physicochemical reaction tank; a pH meter is provided in both the second physicochemical reaction tank and the third physicochemical reaction tank; The polyaluminium chloride dosing point is connected to a polyaluminium chloride storage tank via a polyaluminium chloride dosing pump; the Ca(OH) 2 Primary dosing point, Ca(OH) 2 The secondary dosing points are respectively through Ca(OH) 2 Primary dosing pump, Ca(OH) 2 The secondary dosing pump is connected to Ca(OH) 2 Drug storage barrel; the NaOH dosing point is connected to the NaOH drug storage barrel via a NaOH dosing pump; the polyacrylamide dosing point is connected to the polyacrylamide drug storage barrel via a PAM dosing pump; The polyaluminium chloride dosing point is located inside the first physicochemical reaction tank and adjacent to the water inlet; the Ca(OH) 2 The primary dosing point is located inside the second physicochemical reaction tank and adjacent to the first water outlet.

5. The coating electrophoresis wastewater treatment device according to claim 4, Features: The volume of the physicochemical reaction tank is determined by the following formula: ; Where n=1, 2, 3, 4, V n is the volume of each physicochemical reaction tank, C is the inlet flow rate of the coating electrophoresis wastewater entering the physicochemical reaction device, t n It is the reaction time of coating electrophoresis wastewater in each physicochemical reaction tank.

6. The coating electrophoresis wastewater treatment device according to claim 4, Features: The water inlet is located at the top of the side of the first physicochemical reaction tank; the water outlet is located at the top of the side of the fourth physicochemical reaction tank.

7. The coating electrophoresis wastewater treatment device according to claim 6, Features: The first physicochemical reaction pool and the second physicochemical reaction pool are connected via a first water outlet, the second physicochemical reaction pool and the third physicochemical reaction pool are connected via a second water outlet, and the third physicochemical reaction pool and the fourth physicochemical reaction pool are connected via a third water outlet; every two adjacent physicochemical reaction pools share a side wall; The first water outlet is located at the bottom of the common side wall of the first physicochemical reaction tank and the second physicochemical reaction tank, on a side away from the water inlet; the second water outlet is located at the top of the common side wall of the second physicochemical reaction tank and the third physicochemical reaction tank, on a side away from the first water outlet; the third water outlet is located at the bottom of the common side wall of the third physicochemical reaction tank and the fourth physicochemical reaction tank, on a side away from the second water outlet.

8. The coating electrophoresis wastewater treatment device according to claim 6, Features: A stirrer is installed in the physicochemical reaction tank.

9. The coating electrophoresis wastewater treatment device according to claim 6, Features: The Ca(OH) 2 The secondary dosing point and NaOH dosing point are located inside the third physicochemical reaction tank, and Ca(OH) 2 The secondary dosing point is adjacent to the second water outlet, and the NaOH dosing point is adjacent to the Ca(OH) 2 The secondary dosing point is adjacent to each other; the polyacrylamide dosing point is located inside the fourth physicochemical reaction tank and is adjacent to the third water outlet.

10. The coating electrophoresis wastewater treatment device according to claim 6, Features: The probe of the pH meter in the second physicochemical reaction tank is located at a diagonal position opposite to the first water outlet; the probe of the pH meter in the third physicochemical reaction tank is located at a diagonal position opposite to the second water outlet.

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