Treatment method of banana oil-containing waste liquid

Abstract

The treatment method comprises the following steps: pumping waste liquid into a reaction tank, adding activated carbon, stirring, adjusting the pH value by using high-concentration fluorine dilute acid and calcium hydroxide to form paint slag, carrying out filter pressing by using a plate filter press, detecting and adjusting the fluorine content, and adding PAC and PAM for coagulating sedimentation treatment. According to the method, the paint slag blocking problem is effectively solved, the fluorine content is reduced to 50 mg / L or below, high-molecular organic matter is efficiently removed, the treated wastewater can normally enter a triple-effect system and a biochemical system for subsequent treatment, and the treatment cost is far lower than that of incineration treatment. The problems are effectively solved through an innovative process. According to the method, efficient treatment of complex components in the banana oil-containing waste liquid is realized through the steps of activated carbon adsorption, pH adjustment through acid-base to form paint slag, calcium chloride defluorination, PAC and PAM coagulating sedimentation and the like. Equipment blockage is avoided, it is ensured that the fluorine content of the treated wastewater reaches the standard, the organic matter removal effect is good, and the treatment cost is greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of industrial waste liquid disposal, in particular to a method for disposing thinner-containing waste liquid. Background Art

[0002] In industrial production, particularly in the automotive and furniture painting industries, thinner is widely used as a common solvent in painting processes. For example, in automobile manufacturing, thinner effectively dissolves paint, ensuring uniform application and ensuring product quality. However, the disposal of wastewater containing thinner after use is an increasingly prominent issue.

[0003] The composition of thinner-containing wastewater recovered from automobile manufacturers is composed of 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 significant amounts of paint and organic compounds such as ketones and alcohols. This makes direct biochemical disposal impractical, as the complex composition of these organic compounds makes it difficult for microorganisms to effectively decompose them.

[0004] Traditional treatment methods, when paint residue from thinner-containing wastewater is mixed with waste acid from conventional wastewater treatment, can lead to serious problems. The paint residue solidifies into small, highly viscous colloid flakes that easily clog pipes and plate-and-frame filter presses. Once clogged, treatment efficiency is reduced, equipment maintenance costs are increased, and production may even need to be halted for cleanup, severely impacting production schedules.

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

[0006] Existing treatment technologies for thinner-containing wastewater are either ineffective and fail to meet environmental standards, or are too costly to be widely adopted by businesses. Therefore, the development of an efficient, low-cost, and stable treatment technology for thinner-containing wastewater is urgently needed. Summary of the Invention

[0007] The purpose of the present invention is to provide a method for disposing thinner-containing wastewater. The present invention aims to solve the technical problems that thinner-containing wastewater has complex components and is difficult to treat, resulting in high treatment costs, poor treatment effects, and easy clogging of treatment equipment.

[0008] To achieve the above objectives, the present invention provides the following technical solutions: A method for disposing of waste liquid containing thinners, comprising the following steps: Inject the wastewater containing thinners into the reaction tank; During the injection of the waste liquid, add activated carbon and stir for 20 - 30 minutes; Add high - concentration dilute hydrofluoric acid to adjust the pH to 3 - 4, observe the formation of paint sludge, and then add calcium hydroxide to callback the pH to 6, so that the formed paint sludge is a flaky solid without adhesion; Filter the waste liquid through a plate - type filter press and temporarily store it in the observation tank; After the filtration is completed, use calcium hydroxide to callback the pH to 7 - 8, detect the fluorine content in the wastewater. If the fluorine content is greater than 50mg / L, add an appropriate amount of calcium chloride to remove fluorine, so that the fluorine in the waste liquid is reduced to less than 50mg / L; Add solid PAC and clear water to the PAC reagent tank in batches, stir well and set aside. Slowly add PAM and 1.5 tons of clear water to the PAM reagent tank. Use the dosing system to first add the PAC solution, then add the PAM solution, and then press the wastewater through the plate - and - frame filter press into the observation tank for the next step of disposal.

[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 thinners, the addition amount of activated carbon is 300 - 400kg, the addition amount of solid PAC is 100kg, the addition amount of PAM is 100L, and the addition amount of clear water for both times is 1.5T.

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

[0012] Preferably, the concentration of the high - concentration dilute hydrofluoric acid is 20% - 30%.

[0013] Preferably, when adding the PAC and PAM solutions, the dosing speed is 10 - 20L / min.

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

[0015] Compared with the prior art, the technical solution of the present application has the following technical effects: A method for disposing of waste liquid containing thinners provided by the present invention addresses numerous problems faced by existing treatment methods for thinners. For example, when treated in combination with waste acid, paint sludge is likely to clog pipelines and equipment, incineration disposal is costly, and biochemical treatment is difficult to implement. Through an innovative process, the present invention effectively solves these problems. By using steps such as activated carbon adsorption, adjusting the pH with acid and base to form paint sludge, removing fluorine with calcium chloride, and coagulation precipitation with PAC and PAM, efficient treatment of complex components in the waste liquid containing thinners is achieved. It not only avoids equipment blockage but also ensures that the fluorine content in the treated wastewater meets the standard and the removal effect of organic matter is good, significantly reducing the treatment cost, achieving a win-win situation for environmental protection and economy, and filling the gap in high-efficiency and low-cost treatment technology in this field. Specific Embodiments

[0016] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0017] As a preferred embodiment of the present invention, this embodiment provides a method for disposing of waste liquid containing thinners, including the following steps: Pump 10 tons of wastewater containing thinners into the reaction tank; During the process of pumping in the waste liquid, add 300 - 400 kg of activated carbon and stir for 20 - 30 minutes; Add high-concentration dilute hydrofluoric acid to adjust the pH to 3 - 4, observe the formation of paint sludge, and then add calcium hydroxide to callback the pH to 6 to make the formed paint sludge a flaky solid without adhesion; Press-filter the waste liquid through a plate-and-frame filter press and temporarily store it in the observation tank; After the press-filtration is completed, use calcium hydroxide to callback the pH to 7 - 8, detect the fluorine content in the wastewater. If the fluorine content is greater than 50 mg / L, add an appropriate amount of calcium chloride to remove fluorine to reduce the fluorine in the waste liquid to less than 50 mg / L; Add 100 kg of solid PAC and 1.5 T of clear water to the PAC chemical agent tank in batches, stir well and set aside. Slowly add 100 L of PAM and 1.5 tons of clear water to the PAM chemical agent tank. Use the dosing system to first add 200 L of PAC working solution, then add 50 L of PAM working solution, and then press the wastewater through a plate-and-frame filter press into the observation tank for the next step of disposal.

[0018] The above embodiments provide a complete and systematic process for disposing of waste liquid containing thinners, covering the whole process from pumping the wastewater into the reaction tank to temporarily storing it in the observation tank after multi-step treatment, ensuring the orderly progress of the treatment.

[0019] It should be understood that the PAC described in the present invention is polyaluminum chloride, which is an inorganic polymer coagulant. It is an inorganic polymer water treatment agent with a relatively large molecular weight and a relatively high charge produced by the bridging action of hydroxide ions and the polymerization of polyvalent anions. In the treatment of thinners waste liquid in the present invention, its function is to produce a large number of polynuclear complexes and charged ions through hydrolysis. These substances can compress the double electric layer on the surface of suspended particles, destabilize the particles, and through adsorption, bridging and other effects, make the tiny particles in the waste liquid aggregate to form larger flocs, which is convenient for subsequent removal by precipitation or filtration, effectively reducing the content of suspended solids and some organic matters in the wastewater. PAM is polyacrylamide, which belongs to organic polymer flocculants and can be divided into four types according to ionic characteristics: non-ionic, anionic, cationic and amphoteric. In the treatment of thinners waste liquid, anionic or cationic PAM is usually used. It contains a large number of active groups on its molecular chain and can further combine with the particles that have been preliminarily flocculated. On the basis of the preliminary aggregation of particles by PAC, PAM connects more small flocs through the bridging action of long chains to form larger and denser flocs, accelerating the sedimentation speed of the flocs, improving the solid-liquid separation effect, further removing impurities and some dissolved organic matters in the wastewater, and enhancing the quality of the treated wastewater.

[0020] When the above-mentioned embodiment is implemented, the activated carbon is powdered activated carbon with a particle size range of 100-200 mesh to ensure its good adsorption performance and effectively adsorb the organic matters in the waste liquid. The powdered activated carbon with a particle size of 100-200 mesh has a large specific surface area and many adsorption sites, can contact more fully with organic matters such as ketones and alcohols in the waste liquid, enhance the adsorption effect, further reduce the content of organic matters in the waste liquid, and improve the quality of the treated wastewater.

[0021] In a preferred embodiment, in order to limit the concentration of high-concentration dilute hydrofluoric acid, accurately control the pH adjustment process, ensure the forming effect of paint sludge, and at the same time reduce the introduction of impurities, the concentration of the high-concentration dilute hydrofluoric acid in this embodiment is 20%-30%, ensuring that the paint sludge can be effectively formed during the pH adjustment process without introducing too many impurities.

[0022] When the dilute hydrofluoric acid with a concentration of 20%-30% adjusts the pH to 3-4, it can promote the paint sludge to form flaky solids without adhesive conditions, which is not only conducive to subsequent pressure filtration separation, but also avoids poor treatment effects of the paint sludge caused by too high or too low acid concentration, ensuring the stability of the treatment process.

[0023] In the above-mentioned embodiment, in order to ensure the full mixing of PAC and PAM with the waste liquid and exert the best coagulation and precipitation effect, when adding the PAC and PAM working solutions, the adding speed is 10-20 L / min to ensure the full mixing of the medicaments with the waste liquid and improve the treatment effect.

[0024] In the above embodiments, the feeding rate of 10 - 20 L / min enables PAC and PAM to be evenly dispersed in the waste liquid, giving full play to the coagulation and flocculation effects, effectively promoting the aggregation of fine particles to form large flocs, improving the solid-liquid separation efficiency, and further removing impurities and organic substances in the waste liquid.

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

[0026] The above embodiments can effectively intercept solid impurities such as paint sludge, greatly reducing the content of solid suspended matter in the treated waste liquid, providing better conditions for the further treatment or discharge of the subsequent wastewater, and ensuring the final treatment quality of the entire treatment 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 them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the technical solutions of the present invention, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A method for disposing of waste liquid containing thinners, characterized in that, It includes the following steps: Inject the waste water containing thinners into the reaction tank; During the injection of the waste liquid, add activated carbon and stir for 20 - 30 minutes; Add high - concentration dilute hydrofluoric acid to adjust the pH to 3 - 4, observe the formation of paint sludge, and then add calcium hydroxide to callback the pH to 6, so that the formed paint sludge is a flaky solid without adhesion; Press - filter the waste liquid through a plate - type filter press and temporarily store it in the observation tank; After the press - filtration is completed, use calcium hydroxide to callback the pH to 7 - 8, detect the fluorine content in the waste water. If the fluorine content is greater than 50 mg / L, add an appropriate amount of calcium chloride to remove fluorine, so that the fluorine in the waste liquid is reduced to less than 50 mg / L; Add solid PAC and clear water to the PAC reagent tank in batches, stir well and reserve. Slowly add PAM and 1.5 tons of clear water to the PAM reagent tank. Use the dosing system to first add the PAC working solution, then add the PAM working solution, and then press - filter the waste water through a plate - and - frame filter press into the observation tank for the next treatment.

2. The disposal method of the thinners-containing waste liquid according to claim 1, wherein The activated carbon is powdered activated carbon, and its particle size range is 100 - 200 mesh.

3. The disposal method of the thinners waste liquid according to claim 1, characterized in that, For every 10 tons of waste water containing thinners, the addition amount of activated carbon is 300 - 400 kg, the addition amount of solid PAC is 100 kg respectively, the addition amount of PAM is 100 L, and the addition amount of clear water for both times is 1.5 T.

4. The method for disposing the thinners-containing waste liquid according to claim 3, wherein The addition amount of the PAC working solution is 200 L, and the addition amount of the PAM working solution is 50 L.

5. The method for disposing the thinners-containing waste liquid according to claim 1, wherein The concentration of the high - concentration dilute hydrofluoric acid is 20% - 30%.

6. The disposal method of the thinners waste liquid according to claim 1, characterized in that, When adding the PAC and PAM working solutions, the dosing speed is 10 - 20 L / min.

7. The method for disposing of the thinners waste liquid according to claim 1, characterized in that, The filtration accuracy of the plate - type filter press is 1 - 5 μm.