Flocculating agent for pesticide missible oil preparation machine cleaning wastewater and application thereof

Abstract

The invention discloses a flocculating agent for machine cleaning wastewater of a pesticide missible oil preparation and application of the flocculating agent. The flocculating agent is prepared from the following components in parts by weight: 50-60 parts of an inorganic flocculating agent, 35-45 parts of an organic flocculating agent, 8-12 parts of a demulsification aid and 4-6 parts of a pH regulator. The flocculant disclosed by the invention is good in demulsification effect, high in COD removal rate, high in treatment efficiency, strong in floc stability, economical in cost and wide in wastewater adaptability, and solves the problems of poor demulsification effect, low COD removal rate, large flocculant dosage and the like when an existing flocculant is used for treating pesticide missible oil preparation cleaning wastewater.

Description

Technical Field

[0001] This invention belongs to the field of industrial wastewater treatment technology, specifically relating to a flocculant for cleaning wastewater in the production process of pesticide emulsifiable concentrates, a method for preparing the flocculant, and a method for treating cleaning wastewater from pesticide emulsifiable concentrates using the flocculant. Background Technology

[0002] The production of pesticide emulsifiable concentrates requires regular cleaning of production equipment and containers, generating a large amount of cleaning wastewater. This wastewater has a complex composition, containing pesticide active ingredients, organic solvents, surfactants, and emulsified oils, forming stable oil-in-water (O / W) or water-in-oil (W / O) emulsion systems. This type of wastewater has the following characteristics: High pollutant concentration: COD (chemical oxygen demand) can typically reach tens of thousands to hundreds of thousands of mg / L (far exceeding the level of cutting fluid wastewater). Highly toxic: Contains biologically inhibitory substances, making direct biochemical treatment difficult; High stability: Due to the presence of surfactants, the emulsion system is stable and difficult to demulsify.

[0003] Currently, conventional flocculants such as polyaluminum chloride (PAC) and polyacrylamide (PAM) suffer from problems such as unstable efficacy, high dosage, and large sludge production when treating this type of wastewater, and their removal effect on dissolved organic matter is limited. Therefore, developing a highly efficient and specialized flocculant for cleaning wastewater from pesticide emulsifiable concentrate formulations is of great significance.

[0004] Currently, conventional flocculants such as polyaluminum chloride (PAC) and polyacrylamide (PAM) suffer from problems such as unstable efficacy, high dosage, and large sludge production when treating this type of wastewater, and their removal effect on dissolved organic matter is limited. Therefore, developing a highly efficient and specialized flocculant for cleaning wastewater from pesticide emulsifiable concentrate formulations is of great significance. Summary of the Invention

[0005] To address the difficulty in treating cleaning wastewater generated during the production of existing pesticide emulsifiable concentrates, this invention provides a flocculant specifically designed for this purpose. This flocculant exhibits excellent demulsification performance, high COD removal rate, and low flocculant dosage, thus resolving the problems of poor demulsification, low COD removal rate, and high flocculant dosage associated with existing flocculants in treating pesticide emulsifiable concentrate cleaning wastewater.

[0006] The specific technical solution of this invention is as follows: A flocculant for cleaning wastewater from pesticide emulsifiable concentrate formulations, comprising the following components in parts by weight: 50-60 parts inorganic flocculant, 35-45 parts organic flocculant, 8-12 parts demulsifier, and 4-6 parts pH adjuster.

[0007] The inorganic flocculant comprises 50-60 parts by weight, for example, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, or 60 parts. The inorganic flocculant consists of 30-36 parts by weight of polyaluminum chloride (PAC) and 20-24 parts by weight of polyferric sulfate (PFS). The amount of PAC can be 30, 31, 32, 33, 34, 35, or 36 parts, and the amount of PFS can be 20, 21, 22, 23, or 24 parts. The total amount of PAC and PFS is 50-60 parts.

[0008] The organic flocculant comprises 35-45 parts by weight, for example, 35, 40, or 45 parts. The organic flocculant consists of 26-34 parts by weight of cationic polyacrylamide (CPAM) and 1-11 parts by weight of chitosan quaternary ammonium salt. The amount of cationic polyacrylamide (CPAM) can be 26, 27, 28, 29, 30, 31, 32, 33, or 34 parts, and the amount of chitosan quaternary ammonium salt can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11 parts. The total amount of cationic polyacrylamide (CPAM) and chitosan quaternary ammonium salt is 35-45 parts by weight.

[0009] The demulsifier comprises 8-12 parts by weight, for example, 8, 9, 10, 11, or 12 parts. The demulsifier consists of 5-7 parts by weight of modified diatomaceous earth and 3-5 parts by weight of polydiallyldimethylammonium chloride (PolyDADMAC). The amount of modified diatomaceous earth can be 5, 6, or 7 parts, and the amount of polydiallyldimethylammonium chloride (PolyDADMAC) can be 3, 4, or 5 parts. The total amount of modified diatomaceous earth and polydiallyldimethylammonium chloride (PolyDADMAC) is 8-12 parts by weight.

[0010] The pH adjuster is present in 4-6 parts by weight, for example, 4 parts, 5 parts, or 6 parts. The pH adjuster is solid sodium hydroxide.

[0011] Furthermore, the inorganic and organic flocculants used in the flocculants for cleaning wastewater from pesticide emulsifiable concentrates mentioned above are both commonly used flocculants for wastewater treatment in the prior art and are commercially available.

[0012] Furthermore, the cationic polyacrylamide has a molecular weight of 8-12 million and an ionicity of 20-30%.

[0013] Furthermore, the modified diatomaceous earth is prepared by calcining diatomaceous earth at 400-500℃ for 2-3 hours, followed by surface modification with silane coupling agent KH-550 to obtain modified diatomaceous earth. A typical method for modifying calcined diatomaceous earth with KH-550 is as follows: KH-550 is added to an ethanol aqueous solution and stirred to dissolve. Then, the calcined diatomaceous earth is added to the solution, and the mixture is stirred and reacted at 60-80℃. After the reaction, the mixture is filtered, washed, dried, and ground to obtain modified diatomaceous earth. The amount of KH-550 used is 1%-7% of the mass of the diatomaceous earth, and the concentration of the ethanol aqueous solution is 50-90 wt%.

[0014] This invention also provides a method for preparing a flocculant for cleaning wastewater from pesticide emulsifiable concentrate formulations. In this flocculant, the inorganic flocculant, organic flocculant, and demulsifying agent are mixed evenly and packaged together, while the pH adjuster is packaged separately. During use, the mixture of inorganic flocculant, organic flocculant, and demulsifying agent, along with the pH adjuster, are added to the wastewater separately. Generally, the mixture of inorganic flocculant, organic flocculant, and demulsifying agent is added first, stirred evenly, and then the pH adjuster is added.

[0015] The present invention also provides a method for treating pesticide emulsifiable concentrate cleaning wastewater, the method comprising the step of treating the pesticide emulsifiable concentrate cleaning wastewater with the above-mentioned flocculant.

[0016] Furthermore, the pesticide emulsifiable concentrate cleaning wastewater mentioned in this invention refers to the large amount of wastewater generated during the cleaning of production equipment and containers in the production process of pesticide emulsifiable concentrates. This type of wastewater contains emulsified oil, pesticide residues, and surfactants, and has high COD (tens of thousands to hundreds of thousands of mg / L), high toxicity, and is difficult to demulsify. For example, it can be cleaning wastewater from organophosphorus pesticide emulsifiable concentrates or pyrethroid pesticide emulsifiable concentrates.

[0017] Furthermore, the dosage of the flocculant in this invention varies depending on the COD level of the raw water. The total dosage of inorganic flocculant, organic flocculant, and demulsifier is 1‰ to 10‰ of the wastewater mass, for example, 1‰, 2‰, 3‰, 4‰, 5‰, 6‰, 7‰, 8‰, 9‰, and 10‰. The dosage of pH adjuster ensures that the pH of the wastewater is adjusted to 7.5 to 10.5, for example, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, and 10.5.

[0018] Furthermore, if there are large solid particles in the wastewater, the wastewater can be pretreated by filtration or other methods before adding flocculants to remove large suspended solids.

[0019] Furthermore, first add a mixture of inorganic flocculant, organic flocculant and demulsifier to the wastewater, and stir rapidly at a stirring speed of 200-300 r / min for 2-3 minutes. Then add a pH adjuster to adjust the pH to 7.5-10.5, and stir slowly at a stirring speed of 50-80 r / min for 10-15 minutes to carry out flocculation and sedimentation.

[0020] Furthermore, after flocculation and sedimentation, the oil phase flocculates and precipitates. After settling, the oil-containing flocs are removed by separation. The COD of the supernatant wastewater is greatly reduced, and it is then further treated in a Fenton oxidation unit, a biological treatment system, or an advanced treatment unit.

[0021] This invention provides a highly efficient and specialized flocculant for cleaning wastewater from pesticide emulsifiable concentrate formulations, which has the following advantages: 1. Excellent demulsification effect: For the emulsified system in the cleaning wastewater of pesticide emulsifiable concentrates, the compound demulsifier and flocculant work together to effectively disrupt the stability of the oil-water interface and improve the demulsification efficiency. 2. High COD removal rate: The COD removal rate of cleaning wastewater is over 90%, which is higher than the 60%-75% removal rate of traditional flocculants; 3. High processing efficiency: After adding flocculant, it can quickly flocculate within 20 minutes of stirring, which is time-saving and has high flocculation efficiency; 4. Strong floc stability: The formed flocs are dense and have good settling performance, reducing sludge volume; 5. Wide adaptability: Applicable to cleaning wastewater from the production of various types of pesticide emulsifiable concentrates (such as organophosphates, pyrethroids, etc.); 6. Cost-effective: The amount of flocculant used is small, and the cost of the agent to treat each ton of wastewater is about 0.3-0.5 yuan, which has good economic feasibility. Detailed Implementation

[0022] The following description illustrates exemplary embodiments of the present invention, including various details to aid understanding, and should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the invention. Similarly, for clarity and brevity, descriptions of well-known functions, operations, and structures are omitted in the following description.

[0023] In the following examples and comparative examples, all raw materials used were commercially available products. Polyaluminum chloride, polyferric sulfate, polyaluminum ferric silicate, and polyferric chloride were purchased from Hongyuan Environmental Protection. Cationic polyacrylamide, anionic polyacrylamide, and nonionic polyacrylamide were purchased from Henan Boyuan New Materials. Chitosan and chitosan quaternary ammonium salt were purchased from Nantong Lvshen. Polyethyleneimine was purchased from Wuhan Qianglong.

[0024] Preparation Example Diatomaceous earth was calcined at 450℃ for 2.5 hours. KH-550 was added to a 70wt% ethanol aqueous solution to prepare a 10wt% solution. After stirring and dissolving, the calcined diatomaceous earth was added to the solution at a mass ratio of diatomaceous earth to KH-550 of 1:0.05. The mixture was stirred and reacted at 70℃ for 3 hours. The mixture was then filtered, the filter cake was washed with ethanol, dried, and then ground to obtain modified diatomaceous earth.

[0025] Example 1 A flocculant for cleaning wastewater from pesticide emulsifiable concentrate formulations, comprising the following components in parts by weight: The preparation method of this flocculant is as follows: Inorganic flocculant, organic flocculant, and demulsifier are mixed evenly and packaged separately. The pH adjuster is packaged separately.

[0026] Example 2 A flocculant for cleaning wastewater from pesticide emulsifiable concentrate formulations, comprising the following components in parts by weight: The preparation method of the flocculant is the same as in Example 1.

[0027] Example 3 A flocculant for cleaning wastewater from pesticide emulsifiable concentrate formulations, comprising the following components in parts by weight: The preparation method of the flocculant is the same as in Example 1.

[0028] Comparative Example 1 A flocculant for cleaning wastewater from pesticide emulsifiable concentrate formulations, comprising the following components in parts by weight: The preparation method of the flocculant is the same as in Example 1.

[0029] Comparative Example 2 A flocculant for cleaning wastewater from pesticide emulsifiable concentrate formulations, comprising the following components in parts by weight: The preparation method of the flocculant is the same as in Example 1.

[0030] Comparative Example 3 A flocculant for cleaning wastewater from pesticide emulsifiable concentrate formulations, comprising the following components in parts by weight: The preparation method of the flocculant is the same as in Example 1.

[0031] Comparative Example 4 A flocculant for cleaning wastewater from pesticide emulsifiable concentrate formulations, comprising the following components in parts by weight: The preparation method of the flocculant is the same as in Example 1.

[0032] Comparative Example 5 A flocculant for cleaning wastewater from pesticide emulsifiable concentrate formulations, comprising the following components in parts by weight: The preparation method of the flocculant is the same as in Example 1.

[0033] Comparative Example 6 A flocculant for cleaning wastewater from pesticide emulsifiable concentrate formulations, comprising the following components in parts by weight: The preparation method of the flocculant is the same as in Example 1.

[0034] Application Example 1 The flocculants prepared using the above embodiments and comparative examples were used to treat the cleaning wastewater from the emulsifiable concentrate production line of a pesticide company. The main components of the wastewater were residual fluroxypyr emulsifiable concentrate, 200# solvent oil, DMF, anionic surfactant, and nonionic surfactant. The COD was 98,000 mg / L, the total nitrogen was 1,200 mg / L, and the pH was 6.8.

[0035] The wastewater treatment process is as follows: 1. Take 1000 mL of wastewater into a beaker.

[0036] 2. First, add 2.5g of the flocculant (excluding the pH adjuster) to the beaker. Then, stir rapidly at 250r / min for 2-3 minutes. Next, add the pH adjuster to adjust the pH to 8.5 and stir slowly at 60r / min for 12 minutes to allow for flocculation and sedimentation.

[0037] 3. After flocculation and sedimentation, the oil phase flocculates and settles. After settling, the oil-containing flocs are removed by separation.

[0038] Take the supernatant obtained from the separation and determine the COD content in the wastewater by potassium dichromate method. Determine the total nitrogen content in the wastewater by alkaline potassium persulfate digestion ultraviolet spectrophotometry. Calculate the COD removal rate and total nitrogen removal rate according to the following formula.

[0039] COD removal rate / Total nitrogen removal rate = (COD or total nitrogen content in wastewater before treatment - COD or total nitrogen content in wastewater after treatment) / COD or total nitrogen content in wastewater before treatment 100.

[0040] The treatment effects of each flocculant on wastewater are shown in Table 1.

[0041] Table 1 Application Example 2 The flocculants prepared using the above embodiments and comparative examples were used to treat the cleaning wastewater from the emulsifiable concentrate production line of a pesticide company. The main components of the wastewater were isopropyl chlorpyrifos residue, 200# solvent oil, anionic surfactant, and nonionic surfactant. The COD was 137,000 mg / L, the total nitrogen was 1,900 mg / L, and the pH was 6.5.

[0042] The wastewater treatment process is as follows: 1. Take 1000 mL of wastewater into a beaker.

[0043] 2. First, add 4g of the flocculant (excluding the pH adjuster) to the beaker. Then, stir rapidly at 250 r / min for 2-3 minutes. Next, add the pH adjuster to adjust the pH to 8.5 and stir slowly at 60 r / min for 12 minutes to allow flocculation and sedimentation.

[0044] 3. After flocculation and sedimentation, the oil phase flocculates and settles. After settling, the oil-containing flocs are removed by separation.

[0045] Take the supernatant obtained from the separation and determine the COD content in the wastewater by potassium dichromate method. Determine the total nitrogen content in the wastewater by alkaline potassium persulfate digestion ultraviolet spectrophotometry. Calculate the COD removal rate and total nitrogen removal rate according to the following formula.

[0046] COD removal rate / Total nitrogen removal rate = (COD or total nitrogen content in wastewater before treatment - COD or total nitrogen content in wastewater after treatment) / COD or total nitrogen content in wastewater before treatment 100.

[0047] The treatment effects of each flocculant on wastewater are shown in Table 2.

[0048] Table 2

Claims

1. A flocculant for cleaning wastewater from pesticide emulsifiable concentrate formulations, characterized in that: It consists of the following components in parts by weight: 50-60 parts inorganic flocculant, 35-45 parts organic flocculant, 8-12 parts demulsifier, and 4-6 parts pH adjuster.

2. The flocculant according to claim 1, characterized in that: The inorganic flocculant is composed of polyaluminum chloride and polyferric sulfate, with 30-36 parts by weight of polyaluminum chloride and 20-24 parts by weight of polyferric sulfate.

3. The flocculant according to claim 1, characterized in that: The organic flocculant is composed of cationic polyacrylamide and chitosan quaternary ammonium salt, with 26-34 parts by weight of cationic polyacrylamide and 1-11 parts by weight of chitosan quaternary ammonium salt.

4. The flocculant according to claim 3, characterized in that: The cationic polyacrylamide has a molecular weight of 8-12 million and an ionicity of 20-30%.

5. The flocculant according to claim 1, characterized in that: The demulsifier is composed of modified diatomaceous earth and polydiallyldimethylammonium chloride, with 5-7 parts by weight of modified diatomaceous earth and 3-5 parts by weight of polydiallyldimethylammonium chloride.

6. The flocculant according to claim 5, characterized in that: The modified diatomaceous earth is prepared by calcining the diatomaceous earth at 400-500℃ for 2-3 hours, and then surface modifying it with silane coupling agent KH-550 to obtain modified diatomaceous earth. The amount of KH-550 used is 1%-7% of the mass of the diatomaceous earth.

7. The flocculant according to claim 1, characterized in that: The pH adjuster is sodium hydroxide.

8. A method for treating wastewater from pesticide emulsifiable concentrate cleaning machines, characterized in that: The method includes the step of treating pesticide emulsifiable concentrate cleaning wastewater using any one of claims 1-7; preferably, the total amount of inorganic flocculant, organic flocculant and demulsifying agent in the flocculant is 1‰ to 10‰ of the wastewater mass, and the amount of pH adjuster is sufficient to adjust the pH of the wastewater to 7.5 to 10.

5.

9. The processing method according to claim 8, characterized in that: First, add a mixture of inorganic flocculant, organic flocculant and demulsifier to the wastewater and stir rapidly at a stirring speed of 200-300 r / min for 2-3 minutes. Then, add a pH adjuster to adjust the pH to 7.5-10.5 and stir slowly at a stirring speed of 50-80 r / min for 10-15 minutes to carry out flocculation and sedimentation.

10. The processing method according to claim 8 or 9, characterized in that: The pesticide emulsifiable concentrate cleaning wastewater is the wastewater generated during the cleaning of production equipment and containers during the production process of the pesticide emulsifiable concentrate. The pesticides include organophosphorus pesticides and pyrethroid pesticides.

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