A method for disposing Tian'a water waste liquid

Abstract

The present application relates to a kind of handling methods containing Tianna water waste liquid, including into the reaction tank waste liquid, add activated carbon stirring, with high concentration fluorine dilute acid and calcium hydroxide adjust pH to make paint slag form, after filter pressing by plate filter press, detect and adjust fluoride content, again PAC and PAM are added to carry out coagulation sedimentation treatment.The method effectively solves the problem of paint slag blockage, reduce fluoride content to 50mg / L below, high molecular organic matter is removed efficiently, and the treated wastewater can normally enter three-effect system, biochemical system for subsequent disposal, and the processing cost is far lower than incineration disposal.The present application solves these problems effectively by innovative process.Using activated carbon adsorption, acid-base pH adjustment to make paint slag form, calcium fluoride removal and PAC and PAM coagulation sedimentation, etc., the efficient treatment of complex components in Tianna water waste liquid is realized.It not only avoids equipment blockage, but also ensures that the fluoride content of treated wastewater meets the standard, and the organic matter removal effect is good, which greatly reduces the treatment cost.

Description

Technical Field

[0001] This invention relates to the field of industrial waste liquid treatment technology, specifically a method for treating waste liquid containing thinner. Background Technology

[0002] In industrial production, especially in industries such as automobile manufacturing and furniture painting, thinner is widely used as a common solvent in painting processes. Taking automobile manufacturing as an example, during the painting process, thinner can effectively dissolve paint, helping to achieve uniform spraying and ensuring the quality of the product's appearance. However, the disposal of waste liquid containing thinner after use is becoming increasingly prominent.

[0003] In terms of composition, the thinner-containing wastewater recovered from automobile manufacturing companies contains n-butyl acetate (approximately 15%-20%), ethyl acetate (approximately 15%-19%), n-butanol (approximately 10%-14%), ethanol (approximately 10%-11.9%), and acetone (approximately 5%-10%). The wastewater also contains a large amount of paint and organic matter containing ketones and alcohols. This makes it impossible to directly use biological treatment methods, as the complex organic composition makes it difficult for microorganisms to effectively decompose it.

[0004] In traditional treatment methods, mixing paint residue from thinner-containing wastewater with general externally collected waste acid can cause serious problems. The paint residue will solidify into small, highly adhesive flakes that easily clog pipes and plate and frame filter presses. Once clogging occurs, it not only reduces treatment efficiency but also increases equipment maintenance costs and may even require production shutdowns for cleaning, severely impacting the company's production schedule.

[0005] While incineration can render waste liquid harmless, it is costly. The incineration process consumes a large amount of energy, including fuel costs and equipment operating costs, which represents a significant expense for enterprises, greatly increasing production costs and reducing their economic benefits.

[0006] Existing technologies for treating wastewater containing thinner either fail to meet environmental emission standards or are too costly to be widely adopted in enterprises. Therefore, developing a highly efficient, low-cost, and stable wastewater treatment technology is urgently needed. Summary of the Invention

[0007] The purpose of this invention is to provide a method for disposing of waste liquid containing thinner. This invention aims to solve the technical problems of high treatment costs, poor treatment effect, and easy clogging of treatment equipment caused by the complex composition and high difficulty in treating waste liquid containing thinner.

[0008] To achieve the above objectives, the present invention provides the following technical solution: A method for disposing of waste liquid containing thinner includes the following steps: Wastewater containing thinner was injected into the reaction tank; Add activated carbon during the process of injecting waste liquid and stir for 20-30 minutes; Add high concentration of hydrofluoric acid to adjust the pH to 3-4, observe the formation of paint sludge, then add calcium hydroxide to adjust the pH back to 6, so that the formed paint sludge is a flaky solid and has no adhesiveness. The waste liquid is filtered through a plate filter press and temporarily stored in an observation tank; After pressure filtration, the pH is adjusted to 7-8 with calcium hydroxide. The fluoride content in the wastewater is then tested. If the fluoride content is greater than 50 mg / L, an appropriate amount of calcium chloride is added to remove the fluoride, reducing the fluoride in the wastewater to below 50 mg / L. Solid PAC and clean water are added to the PAC reagent tank in batches and stirred thoroughly before use. PAM and 1.5 tons of clean water are slowly added to the PAM reagent tank. The PAC solution is added first, followed by the PAM solution, using the dosing system. The wastewater is then pressured to the observation tank through a plate and frame filter press for further treatment.

[0009] Preferably, the activated carbon is powdered activated carbon with a particle size range of 100-200 mesh.

[0010] Preferably, for every 10 tons of wastewater containing thinner, the amount of activated carbon added is 300-400 kg, the amount of solid PAC added is 100 kg, the amount of PAM added is 100 L, and the amount of water added for both purification processes is 1.5 T.

[0011] Preferably, the amount of PAC solution added is 200L, and the amount of PAM solution added is 50L.

[0012] Preferably, the concentration of the high-concentration fluorocarbon is 20%-30%.

[0013] Preferably, the addition rate of PAC and PAM working solution is 10-20 L / min.

[0014] Preferably, the filtration accuracy of the plate filter press is 1-5 μm.

[0015] Compared with the prior art, the technical solution of this application has the following technical effects: This invention provides a method for treating wastewater containing thinner, addressing numerous challenges of existing thinner treatment methods. These include issues such as paint sludge clogging pipes and equipment when mixed with waste acid, high incineration costs, and difficulties in implementing biochemical treatment. This invention effectively solves these problems through an innovative process. Utilizing activated carbon adsorption, pH adjustment to form paint sludge, calcium chloride defluorination, and PAC and PAM coagulation and sedimentation, this method achieves highly efficient treatment of the complex components in wastewater containing thinner. It avoids equipment clogging, ensures that the treated wastewater meets fluoride standards and achieves good organic matter removal, significantly reduces treatment costs, and achieves a win-win situation for both environmental protection and economic efficiency, filling a gap in high-efficiency, low-cost treatment technology in this field. Detailed Implementation

[0016] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] As a preferred embodiment of the present invention, this embodiment provides a method for disposing of wastewater containing thinner, comprising the following steps: 10 tons of wastewater containing thinner were pumped into the reaction tank; During the process of injecting waste liquid, add 300-400 kg of activated carbon and stir for 20-30 minutes; Add high concentration of hydrofluoric acid to adjust the pH to 3-4, observe the formation of paint sludge, then add calcium hydroxide to adjust the pH back to 6, so that the formed paint sludge is a flaky solid and has no adhesiveness. The waste liquid is filtered through a plate filter press and temporarily stored in an observation tank; After pressure filtration, the pH is adjusted to 7-8 with calcium hydroxide. The fluoride content in the wastewater is then tested. If the fluoride content is greater than 50 mg / L, an appropriate amount of calcium chloride is added to remove the fluoride, reducing the fluoride in the wastewater to below 50 mg / L. Add 100kg of solid PAC and 1.5T of clean water to the PAC reagent tank in batches, stir thoroughly and set aside. Slowly add 100LPAM and 1.5 tons of clean water to the PAM reagent tank. Use the dosing system to first add 200LPAC working solution, then add 50LPAM working solution. Then, use a plate and frame filter press to press the wastewater to the observation tank for further treatment.

[0018] The above embodiments provide a complete and systematic wastewater treatment process containing thinner, covering the entire process from the wastewater being pumped into the reaction tank to the multi-step treatment and subsequent temporary storage observation tank, ensuring that the treatment is carried out in an orderly manner.

[0019] It should be understood that PAC, as described in this invention, is polyaluminum chloride, an inorganic polymeric coagulant. It is a water treatment agent with a relatively high molecular weight and charge, produced by the bridging effect of hydroxide ions and the polymerization effect of polyvalent anions. In the treatment of thinner wastewater in this invention, its function is to generate a large number of polynuclear complexes and charged ions through hydrolysis. These substances can compress the electric double layer on the surface of suspended particles, destabilizing the particles. Furthermore, through adsorption and bridging, they cause the tiny particles in the wastewater to aggregate into larger flocs, facilitating subsequent removal by sedimentation or filtration, effectively reducing the content of suspended solids and some organic matter in the wastewater. PAM, or polyacrylamide, is an organic polymeric flocculant, which can be classified into four types according to its ionic properties: nonionic, anionic, cationic, and amphoteric. In the treatment of thinner wastewater, anionic or cationic PAM is commonly used. Its molecular chain contains a large number of active groups, which can further bind with the already preliminarily flocculated particles. Based on the initial aggregation of particles by PAC, PAM connects more small flocs through the bridging effect of long chains, forming larger and denser flocs, accelerating the settling speed of flocs, improving the solid-liquid separation effect, further removing impurities and some dissolved organic matter in wastewater, and improving the quality of treated wastewater.

[0020] In the above embodiments, the activated carbon is powdered activated carbon with a particle size range of 100-200 mesh to ensure good adsorption performance and effective adsorption of organic matter in the waste liquid. Powdered activated carbon of 100-200 mesh has a large specific surface area and numerous adsorption sites, allowing for more thorough contact with ketones, alcohols, and other organic matter in the waste liquid, enhancing adsorption, further reducing the organic matter content in the waste liquid, and improving the quality of the treated wastewater.

[0021] In a preferred embodiment, in order to limit the concentration of high-concentration hydrofluoric acid, precisely control the pH adjustment process, ensure the molding effect of paint sludge, and reduce the introduction of impurities, the concentration of high-concentration hydrofluoric acid in this embodiment is 20%-30%, which ensures that the paint sludge can be effectively molded during the pH adjustment process without introducing too many impurities.

[0022] When the pH of 20%-30% fluoroacid is adjusted to 3-4, it can promote the formation of flaky solids without stickiness in the paint residue. This is beneficial for subsequent pressure filtration and separation, and avoids poor paint residue treatment due to excessively high or low acid concentration, thus ensuring the stability of the treatment process.

[0023] In the above embodiments, in order to ensure that PAC and PAM are fully mixed with the waste liquid and achieve the best coagulation and sedimentation effect, the addition rate of PAC and PAM is 10-20 L / min when adding the working solution, so as to ensure that the reagents are fully mixed with the waste liquid and improve the treatment effect.

[0024] In the above embodiments, the addition rate of 10-20 L / min allows PAC and PAM to be evenly dispersed in the waste liquid, giving full play to their coagulation and flocculation effects, effectively promoting the aggregation of small particles into large flocs, improving solid-liquid separation efficiency, and further removing impurities and organic matter from the waste liquid.

[0025] In some preferred embodiments, in order to ensure efficient separation of paint residue and waste liquid and improve the purity of the treated wastewater, the plate filter press has a filtration accuracy of 1-5μm, which can effectively separate paint residue and waste liquid and ensure the quality of the treated wastewater.

[0026] The above embodiments can effectively intercept solid impurities such as paint residue, significantly reducing the content of suspended solids in the treated wastewater, providing better conditions for further treatment or discharge of subsequent wastewater, and ensuring the final treatment quality of the entire process.

[0027] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for treating waste liquid containing thinner, characterized in that, Includes the following steps: Wastewater containing thinner was injected into the reaction tank; During the process of injecting waste liquid, activated carbon is added and stirred for 20-30 minutes. The activated carbon is in powder form with a particle size range of 100-200 mesh. Add high-concentration hydrofluoric acid to adjust the pH to 3-4. The concentration of the high-concentration hydrofluoric acid is 20%-30%. Observe the formation of the paint sludge. Then add calcium hydroxide to adjust the pH back to 6 so that the formed paint sludge is a flaky solid and has no adhesiveness. The waste liquid is filtered through a plate filter press and temporarily stored in an observation tank; After pressure filtration, the pH is adjusted to 7-8 with calcium hydroxide. The fluoride content in the wastewater is then tested. If the fluoride content is greater than 50 mg / L, an appropriate amount of calcium chloride is added to remove the fluoride, reducing the fluoride in the wastewater to below 50 mg / L. Solid PAC and clean water are added to the PAC reagent tank in batches and stirred thoroughly before use. PAM and 1.5 tons of clean water are slowly added to the PAM reagent tank. The PAC solution is added first, followed by the PAM solution, using the dosing system. The wastewater is then pressured to the observation tank through a plate and frame filter press for further treatment.

2. The method for treating wastewater containing thinner according to claim 1, characterized in that, For every 10 tons of wastewater containing thinner, the amount of activated carbon added is 300-400 kg, the amount of solid PAC added is 100 kg, the amount of PAM added is 100 L, and the amount of clean water added twice is 1.5 T each time.

3. The method for treating wastewater containing thinner according to claim 2, characterized in that, The amount of PAC solution added is 200L, and the amount of PAM solution added is 50L.

4. The method for treating wastewater containing thinner according to claim 1, characterized in that, When adding PAC and PAM working solutions, the addition rate is 10-20 L / min.

5. The method for treating wastewater containing thinner according to claim 1, characterized in that, The filtration accuracy of the plate filter press is 1-5μm.