Method for treating acephate waste liquid

Abstract

This application relates to the technical field of hazardous waste treatment, specifically to a method for treating acephate waste liquid. The method includes: pretreatment, hydrolysis reaction, oxidation reaction, filtration, and wastewater treatment. The hydrolysis reaction involves adding a composite alkali agent to the pretreated waste liquid to conduct a hydrolysis reaction, obtaining hydrolyzed waste liquid. The composite alkali agent includes 1-1.5 wt.% modified magnesium oxide and 4-8 wt.% calcium hydroxide; the amount of composite alkali agent added is 3-5 times the weight of the pretreated waste liquid. The oxidation reaction involves adding calcium hypochlorite to the hydrolyzed waste liquid to conduct an oxidation reaction, obtaining oxidized material; the molar ratio of calcium hypochlorite to residual hydrogen sulfide in the hydrolyzed waste liquid is (1.2-1.5):1. Compared to traditional direct incineration methods, the treatment method of this application can solve problems such as incineration corrosion, flue blockage, and high treatment costs, and also has the characteristics of energy saving and high efficiency.

Description

Technical Field

[0001] This application relates to the technical field of hazardous waste treatment, and in particular to a method for treating acephate waste liquid. Background Technology

[0002] Acephate is a widely used organophosphorus pesticide. During its industrial production, the distillation process continuously generates large amounts of phosphorus-containing distillation residue, known as acephate waste liquid. This waste liquid is classified as hazardous waste, containing a total phosphorus content exceeding 10% and toxic components such as acephate and spermine. Improper treatment can cause serious pollution to soil, water bodies, and other ecological environments, while also posing safety hazards. Therefore, there is an urgent need to develop efficient and compliant treatment technologies.

[0003] Currently, there are publicly available technologies for treating acephate waste liquid. For example, invention patent CN112390235A discloses a method for treating acephate residue by distillation, specifically by direct incineration. However, in practice, it has been found that incineration treatment has significant drawbacks: Firstly, due to the extremely high phosphorus content in acephate waste liquid, a large amount of phosphorus oxides are generated during incineration. These substances are highly corrosive, and when the waste liquid directly enters the incineration system, it will cause severe corrosion to the boiler tubes, shortening the equipment's service life. Secondly, phosphorus oxides and other impurities generated during incineration easily deposit in the flue, leading to frequent coking and blockage of the flue passages. These problems not only significantly increase the frequency and cost of equipment maintenance and repair but also reduce the operating efficiency of the flue gas treatment system, thereby increasing the risk of exceeding environmental emission standards and failing to meet the needs of large-scale, low-cost, and compliant industrial treatment.

[0004] Given the shortcomings of existing technologies, there is an urgent need to develop a method for treating acephate waste liquid that can solve the problems of incineration corrosion, flue blockage, and high treatment costs, while also being energy-saving and highly efficient, thus filling the gap in existing technologies and meeting the actual needs of industrial production. Summary of the Invention

[0005] This application provides a method for treating acephate waste liquid. Compared with traditional direct incineration methods, the method of this application can solve problems such as incineration corrosion, flue blockage, and high treatment costs, and also has the characteristics of energy saving and high efficiency.

[0006] This application provides a method for treating acephate waste liquid, which adopts the following technical solution:

[0007] A method for treating acephate waste liquid, the method specifically includes the following steps: pretreatment, hydrolysis reaction, oxidation reaction, filtration, and wastewater treatment;

[0008] The hydrolysis reaction involves adding a composite alkali agent to the pretreated waste liquid to carry out the hydrolysis reaction, thereby obtaining the hydrolyzed waste liquid; the composite alkali agent comprises 1-1.5 wt.% modified magnesium oxide and 4-8 wt.% calcium hydroxide; the amount of the composite alkali agent added is 3-5 times the weight of the pretreated waste liquid; the conditions for the hydrolysis reaction are: reaction temperature 50-60℃, reaction time 1.5-2.5h, and pH controlled at 10-12;

[0009] The oxidation reaction involves adding calcium hypochlorite to the waste liquid after hydrolysis to carry out the oxidation reaction, thereby obtaining the material after the oxidation reaction; the molar ratio of the calcium hypochlorite to the residual hydrogen sulfide in the waste liquid after hydrolysis is controlled to be (1.2-1.5):1;

[0010] The wastewater treatment involves using a wastewater treatment system to biochemically treat the filtered filtrate to obtain recycled water.

[0011] The acephate waste liquid contains 60-80% acephate, 10-15% spermine, and 3-5% insoluble impurities.

[0012] Optionally, the effective chlorine content of the calcium hypochlorite is ≥65%.

[0013] Optionally, the oxidation reaction conditions are: reaction temperature 25-35℃; reaction time 1-2h.

[0014] Optionally, the composite alkali agent further includes 0.5-1 wt.% nano-hydroxyapatite.

[0015] Optionally, the treatment method further includes an alkaline washing absorption device for absorbing the inert gas that overflows during the hydrolysis reaction.

[0016] Optionally, the treatment method further includes solidifying the residue generated from the pretreatment step and the filtration process; after the solidified residue meets the hazardous waste landfill control standards, it is then disposed of in a landfill.

[0017] Optionally, the biochemical treatment includes anaerobic treatment and aerobic treatment.

[0018] Optionally, the recycled water can be reused in the preparation of the composite alkali agent used in the hydrolysis reaction.

[0019] Optionally, the pretreatment involves filtering the acephate waste liquid to remove insoluble impurities and suspended solids.

[0020] Optionally, the filtration is performed by using a filter press to filter the material after the oxidation reaction.

[0021] In one specific embodiment, a method for treating acephate waste liquid includes the following steps:

[0022] (1) Pretreatment: Filter the acephate waste liquid to remove insoluble impurities and suspended solids to obtain pretreated waste liquid.

[0023] (2) Hydrolysis reaction: A composite alkali agent is added to the pretreated waste liquid to carry out a hydrolysis reaction, and a post-hydrolysis waste liquid is obtained; the composite alkali agent includes 1-1.5 wt.% modified magnesium oxide and 4-8 wt.% calcium hydroxide; the amount of composite alkali agent added is 3-5 times the weight of the pretreated waste liquid; the conditions for the hydrolysis reaction are: reaction temperature 50-60℃, reaction time 1.5-2.5h, and pH controlled at 10-12; an alkali washing absorption device is set up to adsorb the acidic gas overflowing during the hydrolysis reaction. Further, the composite alkali agent also includes 0.5-1 wt.% nano-hydroxyapatite.

[0024] (3) Oxidation reaction: Add calcium hypochlorite powder with an effective chlorine content of ≥65% to the waste liquid after hydrolysis reaction to carry out oxidation reaction to obtain the material after oxidation reaction; control the molar ratio of calcium hypochlorite to residual hydrogen sulfide in the waste liquid after hydrolysis reaction to be (1.2-1.5):1; the conditions for oxidation reaction are: reaction temperature 25-35℃; reaction time 1-2h.

[0025] (4) Filtration: Filter the material after the oxidation reaction to remove impurities and precipitates generated during the reaction and obtain the filtrate.

[0026] (5) Wastewater treatment: The filtrate after filtration is biochemically treated using a wastewater treatment system to obtain recycled water; the biochemical treatment includes anaerobic treatment and aerobic treatment; the recycled water can be reused in the preparation of the composite alkali agent used in the hydrolysis reaction.

[0027] (6) Solidification and landfill: The residue generated from pretreatment and filtration is solidified; after the solidification treatment, the residue meets the control standards for hazardous waste landfill, it is disposed of in a landfill.

[0028] In summary, this application includes at least one of the following beneficial technical effects:

[0029] Compared with traditional direct incineration methods, this application has significant technical, economic, and safety advantages, the specific technical effects of which are as follows:

[0030] (1) Excellent treatment effect and strong compliance: It can achieve a hydrolysis rate of acephate greater than 95%, and the residual phosphorus in the liquid after hydrolysis and oxidation is less than 0.5%. The main pollutants are completely degraded, and the phosphorus removal effect is significant, meeting the environmental protection requirements for hazardous waste treatment.

[0031] (2) Avoid equipment hazards and reduce maintenance costs: By abandoning the direct incineration process, the problems of equipment corrosion and flue coking caused by phosphorus oxides during incineration are completely avoided, reducing the frequency and cost of equipment maintenance, ensuring continuous and stable operation of the treatment process, and reducing the risk of exceeding environmental standards.

[0032] (3) Reduce treatment costs and improve economic efficiency: The total treatment cost is reduced by more than 20% compared with the traditional incineration method. At the same time, by recycling water, water consumption and treatment costs are further reduced, which is suitable for the cost requirements of industrial-scale treatment and facilitates promotion and application.

[0033] (4) Strengthen safety management and control to ensure production safety: reduce hydrogen sulfide emission by adjusting pH through alkaline hydrolysis, and combine the dual prevention and control measures of adsorbing waste gas with alkaline washing absorption device and removing residual hydrogen sulfide by oxidation treatment to effectively avoid the safety hazards caused by hydrogen sulfide and balance environmental protection compliance and production safety.

[0034] (5) Full-process compliance, suitable for large-scale application: It covers the entire process of acephate waste liquid from pretreatment to residue disposal. The parameters of each link are precise and controllable, realizing the graded treatment of pollutants and the full-process compliant management and control of hazardous waste, and is suitable for industrial large-scale treatment needs. Attached Figure Description

[0035] Figure 1 A flowchart illustrating the method for treating acephate waste liquid provided in this application. Detailed Implementation

[0036] Before describing the embodiments of this application in detail, it should be understood that the terminology used herein is for the purpose of describing a particular embodiment only. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the term pertains.

[0037] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, in the description of this application, unless otherwise stated, "multiple" means two or more.

[0038] The endpoints and any values ​​of the ranges disclosed in this application are not limited to the precise ranges or values, and such ranges or values ​​should be understood to include values ​​close to such ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0039] In this application, the terms "comprising" or "including" are open-ended expressions, meaning they include the content specified in this application but do not exclude other aspects.

[0040] This application provides a method for treating acephate waste liquid. (Reference) Figure 1 The treatment method includes, in sequence, pretreatment, hydrolysis reaction, oxidation reaction, filtration, wastewater treatment, and solidification and landfill. The specific operational details of each step are as follows:

[0041] (a) Preprocessing

[0042] The acephate waste liquid is pretreated by filtration to remove some insoluble impurities and suspended solids. Filtration parameters can be optimized based on actual filtration results to improve impurity removal efficiency.

[0043] Pretreatment uses physical filtration to remove insoluble impurities and suspended solids from the waste liquid, achieving preliminary solid-liquid separation. On the one hand, this prevents insoluble impurities from clogging subsequent pipelines and equipment, ensuring smooth operation of the entire treatment process; on the other hand, it avoids the adsorption of acephate by impurities, preventing the loss of hydrolysis reaction substrates and ensuring that the hydrolysis reaction efficiency is not affected, laying the foundation for subsequent treatment stages.

[0044] (ii) Hydrolysis reaction

[0045] Prepare a composite alkali agent, including 1-1.5 wt.% modified magnesium oxide and 4-8 wt.% calcium hydroxide. Add the composite alkali agent to the pretreated waste liquid to carry out a hydrolysis reaction. The amount of composite alkali agent added is 3-5 times the weight of the pretreated waste liquid.

[0046] Meanwhile, by adjusting the feed rate, the hydrolysis reaction conditions are controlled as follows: reaction temperature 50-60℃, reaction time 1.5-2.5h, and pH controlled at 10-12, to complete the hydrolysis reaction. An alkaline washing and absorption device is also installed to adsorb and treat the acidic gases overflowing during the hydrolysis reaction.

[0047] The hydrolysis of acephate under alkaline conditions follows the principle of the following reaction: 2C₂ + 4H₂O 10NO3PS + 3Ca(OH)2 → 2CH3NH2 + 2CH3COOH + Ca3(PO4)2 + 2H2S. In the hydrolysis reaction, acephate contains phosphoester bonds (POC) in its molecular structure. Under the alkaline environment provided by calcium hydroxide, water molecules act as nucleophiles, attacking the carbon atoms of the phosphoester bonds and initiating the hydrolysis reaction, decomposing acephate into methylamine, acetic acid, phosphate, hydrogen sulfide, and a small amount of intermediate products. Simultaneously, the slow-release alkaline properties of modified magnesium oxide extend the pH stability of the reaction system, shortening the hydrolysis reaction cycle to 1.5-2.5 hours. The core objective is to achieve the initial degradation of the main pollutant, converting the difficult-to-treat acephate into easily processed small molecules. Precise pH control ensures complete hydrolysis while inhibiting hydrogen sulfide escape, reducing safety hazards. The accompanying alkaline washing and absorption device adsorbs any overflowing acidic gases, reducing environmental pollution risks.

[0048] In addition, increasing the reaction temperature can improve the hydrolysis rate, but excessively high temperatures may cause some low flash point substances to burn and accelerate the release of hydrogen sulfide. Therefore, the reaction temperature is maintained at 50-60℃ by controlling the feed rate and the reaction time is controlled at 1.5-2.5h. Extending the reaction time helps to ensure complete hydrolysis.

[0049] The composite alkali agent can also incorporate 0.5-1% nano-hydroxyapatite as a catalyst. Its surface active sites can directionally activate the phosphoester bond (POC) of acephate, increasing the hydrolysis rate from 95% to over 98%, and reducing the residual phosphorus content to below 0.3%, thus solving the problem of low-concentration residue.

[0050] (III) Oxidation reaction

[0051] Calcium hypochlorite powder with an effective chlorine content ≥65% was selected as the oxidant and added to the waste liquid after the hydrolysis reaction. The molar ratio of calcium hypochlorite to residual hydrogen sulfide in the waste liquid after the hydrolysis reaction was controlled at (1.2-1.5):1. The reaction temperature was maintained at 25-35℃, and the reaction time was controlled at 1-2 hours to complete the oxidation reaction.

[0052] Utilizing the strong oxidizing properties of calcium hypochlorite, it reacts with residual pollutants in the wastewater after hydrolysis through a redox reaction, achieving deep degradation of the pollutants. Its main functions include: first, oxidizing residual sulfide in the wastewater after hydrolysis to elemental sulfur, facilitating subsequent filtration and removal; second, decomposing residual large-molecule or high-boiling-point organic matter into smaller-molecule organic matter, disrupting its molecular structure and improving the degradation effect of subsequent wastewater biochemical treatment; and third, eliminating the yellow or brown color of the wastewater by removing colored intermediates such as quinones and azo compounds produced by side reactions, while also removing the accompanying irritating odor and improving the quality of the effluent.

[0053] (iv) Filtering

[0054] A filter press is used to filter the material after the oxidation reaction, separating impurities and precipitates generated during the reaction. Polyaluminum chloride (PAC) and polyacrylamide (PAM) can be added during the process to optimize sedimentation and filtration. Activated silica can also be added during the optimization process to enhance the compressive and shear strength of the sulfur flocs, preventing floc breakage and resulting turbidity in the effluent.

[0055] In the filtration process, the filter media of the filter press traps solid impurities and sediments in the material. Simultaneously, the adsorption and bridging effects of the flocculant promote the sedimentation of solid particles, improving filtration efficiency. Filtration separates elemental sulfur, impurities, and other precipitates produced by the oxidation reaction, purifying the material after the oxidation reaction and reducing the load on subsequent wastewater treatment stages. Adding activated silica can solve the problems of hydrophobic, loosely structured, and easily broken sulfur flocs, preventing turbidity in the effluent and ensuring the stability of the filtrate quality.

[0056] (v) Wastewater treatment

[0057] The filtered filtrate is sent to a wastewater treatment system for sequential anaerobic and aerobic treatment to degrade pollutants. The treated water is then reused in the preparation of the composite alkali agent used in the hydrolysis reaction.

[0058] In the wastewater treatment process, the metabolic activities of anaerobic and aerobic microorganisms are utilized. Anaerobic microorganisms degrade large molecular pollutants, converting them into smaller molecules, while aerobic microorganisms further oxidize and decompose these smaller pollutants into harmless carbon dioxide and water, achieving complete pollutant degradation. This step can degrade pollutants such as methylamine and acetic acid in the filtrate, ensuring that the wastewater meets treatment standards. The recycled water is reused for lime water preparation, forming a water resource cycle, reducing the consumption of fresh water resources, lowering overall treatment costs, and aligning with green and environmentally friendly treatment concepts.

[0059] (vi) Solidification landfill

[0060] The residues generated from the pretreatment and filtration steps are collected, solidified, and then disposed of in a landfill once the solidification process meets the hazardous waste landfill control standards.

[0061] In the solidification and landfilling step, a solidifying agent is added to fix toxic and hazardous substances in the residue inside the solidified body, reducing the risk of leaching and ensuring compliance with hazardous waste landfill control standards. This step enables the compliant disposal of hazardous waste residue generated from pretreatment and filtration, preventing the leakage of toxic and hazardous substances from the residue, avoiding soil and water pollution, ensuring ecological and environmental safety, and achieving full-process compliant management of acephate waste liquid.

[0062] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0063] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0064] In this application, the modified magnesium oxide used was purchased from Jiangsu Zehui Magnesium-based New Material Technology Co., Ltd., model ZH-M072; the nano-hydroxyapatite had a purity ≥95% and a particle size controlled between 20-40nm; the calcium hypochlorite had a moisture content <3% and an available chlorine content greater than 65%. In this embodiment, the available chlorine content of the calcium hypochlorite used was 68%.

[0065] The present application will be further described in detail below with reference to the embodiments and test results.

[0066] In the following examples, the acephate waste liquid treated specifically includes the following components: acephate 72.4%, spermine 11.2%, insoluble impurities 3.6%, and other high-boiling-point organic matter.

[0067] Example 1

[0068] This embodiment provides a method for treating acephate waste liquid.

[0069] The processing method specifically includes the following steps:

[0070] (1) Pretreatment: Filter the acephate waste liquid to remove insoluble impurities and suspended solids to obtain pretreated waste liquid.

[0071] (2) Hydrolysis reaction: A composite alkali agent was added to a predetermined weight of the pretreated waste liquid to carry out a hydrolysis reaction, resulting in a post-hydrolysis waste liquid. The composite alkali agent consisted of 1 wt.% modified magnesium oxide and 6 wt.% calcium hydroxide; the amount of composite alkali agent added was 4 times the weight of the pretreated waste liquid. The conditions for the hydrolysis reaction were: reaction temperature 55℃, reaction time 2h, and pH controlled at 10-12. At the same time, an alkali washing absorption device was used to adsorb the acidic gas that overflowed during the hydrolysis reaction.

[0072] (3) Oxidation reaction: Calcium hypochlorite powder is added to the waste liquid after hydrolysis reaction to carry out the oxidation reaction and obtain the material after oxidation reaction. The molar ratio of calcium hypochlorite to residual hydrogen sulfide in the waste liquid after hydrolysis reaction is controlled to be 1.5:1; the conditions for oxidation reaction are: reaction temperature 30℃; reaction time 1.5h.

[0073] (4) Filtration: Filter the material after the oxidation reaction to remove impurities and precipitates generated during the reaction and obtain the filtrate.

[0074] (5) Wastewater treatment: The filtrate after filtration is treated anaerobically and aerobically using a wastewater treatment system to obtain recycled water.

[0075] (6) Solidification and landfill: The residue generated from pretreatment and filtration is solidified; after the solidification treatment, the residue meets the control standards for hazardous waste landfill, it is disposed of in a landfill.

[0076] Table 1. Some parameters involved in the examples and comparative examples.

[0077]

[0078] Example 2-13

[0079] Examples 2-13 each provide a method for treating acephate wastewater. The difference between the above treatment methods lies in the parameter control during the process, as shown in Table 1.

[0080] Specifically, the differences between Examples 1-13 are as follows:

[0081] The difference between Examples 1-3 is that the amount of modified magnesium oxide added is different, while the other operation steps are the same as those in Example 1.

[0082] The difference between Examples 2 and 4-5 is that the amount of calcium hydroxide added is different, while the other operation steps are the same as in Example 2.

[0083] The difference between Examples 2 and 6-7 is that the weight of the composite alkali agent is a different multiple of the weight of the pretreated waste liquid, while the other operating steps are the same as in Example 2.

[0084] The difference between Examples 2 and 8 is that the molar ratio of calcium hypochlorite to residual hydrogen sulfide is different, while the other operating steps are the same as in Example 2.

[0085] The difference between Examples 2 and 9-13 is that nano-hydroxyapatite is added to the composite alkali agent, and the amount of nano-hydroxyapatite added increases sequentially. The remaining operation steps are consistent with Example 2.

[0086] Comparative Examples 1-6

[0087] Comparative Examples 1-6 each provide a method for treating acephate wastewater. The difference between the above treatment methods lies in the parameter control during the process, as shown in Table 1.

[0088] Specifically, the differences between Examples 1-6 are as follows:

[0089] The difference between Comparative Examples 1-2 and Example 2 is that the amount of modified magnesium oxide added is different, while the other operation steps are the same as in Example 1.

[0090] The difference between Comparative Example 3 and Example 2 is that the amount of calcium hydroxide added is different, while the other operating steps are the same as in Example 2.

[0091] The difference between Comparative Example 4 and Example 2 is that the weight of the composite alkali agent is a different multiple of the weight of the pretreated waste liquid, while the other operating steps are the same as in Example 2.

[0092] The difference between Comparative Examples 5-6 and Example 2 is that the molar ratio of calcium hypochlorite to residual hydrogen sulfide is different, while the other operating steps are the same as in Example 2.

[0093] Comparative Example 7

[0094] This comparative example provides a method for treating acephate waste liquid.

[0095] The difference between this treatment method and Example 2 is that the oxidation reaction step is not performed, while the remaining operation steps are consistent with Example 2.

[0096] Comparative Example 8

[0097] This comparative example provides a method for treating acephate waste liquid.

[0098] The difference between this treatment method and Example 2 is that the hydrolysis reaction step is not performed, while the remaining operation steps are consistent with Example 2.

[0099] Comparative Example 9

[0100] This comparative example provides a method for treating acephate waste liquid.

[0101] The specific processing method is as follows:

[0102] (1) Pretreatment: Filter the acephate waste liquid to remove insoluble impurities and suspended solids to obtain pretreated waste liquid.

[0103] (2) Incineration treatment: The pretreated waste liquid is sent into the inlet of the rotary kiln incinerator through a liquid spray gun. The incinerator includes a rotary kiln and a secondary combustion chamber. The rotary kiln incineration temperature is 800-1000℃, the secondary combustion chamber temperature is 1100-1200℃, and the flue gas residence time is 2-3s. The incineration flue gas is discharged after rapid cooling, deacidification and dust removal. The incineration residue is sent to a hazardous waste landfill for disposal.

[0104] Comparative Example 10

[0105] This comparative example provides a method for treating acephate wastewater. The difference between this method and Comparative Example 9 is that, instead of an oxidation reaction step, the wastewater treatment step is replaced with incineration.

[0106] The specific processing method is as follows:

[0107] (1) Pretreatment: Filter the acephate waste liquid to remove insoluble impurities and suspended solids to obtain pretreated waste liquid.

[0108] (2) Hydrolysis reaction: A composite alkali agent was added to a predetermined weight of the pretreated waste liquid to carry out a hydrolysis reaction, resulting in a post-hydrolysis waste liquid. The composite alkali agent consisted of 1.25 wt.% modified magnesium oxide and 6 wt.% calcium hydroxide; the amount of composite alkali agent added was 4 times the weight of the pretreated waste liquid. The conditions for the hydrolysis reaction were: reaction temperature 55℃, reaction time 2h, and pH controlled at 10-12. At the same time, an alkali washing absorption device was used to adsorb the acidic gas that overflowed during the hydrolysis reaction.

[0109] (3) Filtration treatment: The material after hydrolysis reaction is filtered to remove impurities and precipitates generated during the reaction process and obtain the filtrate.

[0110] (4) Incineration treatment: The filtered waste liquid is sent into the inlet of the rotary kiln incinerator through a liquid spray gun. The incinerator includes a rotary kiln and a secondary combustion chamber. The rotary kiln incineration temperature is 800-1000℃, the secondary combustion chamber temperature is 1100-1200℃, and the flue gas residence time is 2-3s. The incineration flue gas is discharged after rapid cooling, deacidification and dust removal to meet the standards. The incineration residue is sent to the hazardous waste landfill for disposal.

[0111] Performance test results

[0112] The processing results of the above embodiments and comparative examples were tested as follows. The test results are shown in Table 2.

[0113] The detection method is as follows:

[0114] (1) Hydrolysis rate of acephate

[0115] The concentration of acephate in the waste liquid before and after the hydrolysis reaction was determined by high performance liquid chromatography (HPLC), and the hydrolysis rate was calculated. The formula for calculating the hydrolysis rate is as follows: Hydrolysis rate = (C0 - C...) t ) / C0×100%; where C0 is the initial concentration of acephate in the waste liquid before the hydrolysis reaction, C t This represents the concentration of acephate in the waste liquid after the hydrolysis reaction.

[0116] (2) Residual phosphorus content

[0117] The total phosphorus concentration in the liquid after hydrolysis and oxidation was determined by ammonium molybdate spectrophotometry, and the residual phosphorus rate was calculated. Under acidic conditions, the sample was digested with potassium persulfate to convert all phosphorus into orthophosphate, which then reacted with ammonium molybdate to form phosphomolybdic acid. This phosphomolybdic acid was reduced to a blue complex by ascorbic acid, and the final concentration was determined by colorimetric analysis at 700 nm.

[0118] (3) Hydrogen sulfide removal rate

[0119] The concentration of hydrogen sulfide in the waste liquid before and after the oxidation reaction was determined by gas chromatography, and the removal rate was calculated. The formula for calculating the removal rate is as follows: Removal rate = (C′0 - C′) / (C′0 - C′0 ... t ) / C′0×100%; where C′0 is the initial concentration of hydrogen sulfide in the waste liquid before the oxidation reaction, C′ t This represents the concentration of hydrogen sulfide in the waste liquid after the oxidation reaction.

[0120] Table 2 Test Results

[0121]

[0122] Table 2 shows that in Examples 1-8 (without nano-hydroxyapatite), the hydrolysis rate of acetamiprid phosphorus remained stable at 95-96.3%, the phosphorus residue was 0.42-0.49%, and the hydrogen sulfide removal rate was 99.2-99.8%. Compared with Example 2, in Comparative Examples 1-3, excessive or insufficient modified magnesium oxide or insufficient calcium hydroxide dosage led to a decrease in the hydrolysis rate of acetamiprid phosphorus and an increase in the phosphorus residue. In Comparative Example 4, the dosage of the composite alkali agent was too low, resulting in a significant decrease in the hydrolysis rate to 91.2% and an increase in the phosphorus residue to 0.68%, demonstrating the necessity of adding 3-5 times the dosage of the composite alkali agent. In Comparative Example 5, the reduced proportion of calcium hypochlorite significantly decreased the hydrogen sulfide removal rate to 98.5%, demonstrating the necessity of the oxidation step. In Comparative Example 6, the excessively high proportion of calcium hypochlorite resulted in a hydrogen sulfide removal rate close to 100%, but this would increase costs and byproducts, and therefore was not preferred.

[0123] Examples 9-13 (with the addition of nano-hydroxyapatite) showed that the hydrolysis rate of acetamiprid phosphorus was increased to 97.2-98.1%, and the residual phosphorus content was reduced to 0.28-0.35%, perfectly demonstrating the technical effect of nano-hydroxyapatite as a catalyst and solving the problem of low-concentration residue. Among them, Example 10 (0.5% addition) showed the best effect, with a hydrolysis rate of 98.1% and a residual phosphorus content of 0.28%.

[0124] Comparative Example 7 (no oxidation): The hydrogen sulfide removal rate plummeted to 85.2%, proving that the oxidation step is crucial for deodorization and desulfurization; Comparative Example 8 (no hydrolysis): The hydrolysis rate of acephate was only 82.3%, with phosphorus residue as high as 1.25%, proving that hydrolysis is the core step in organophosphorus degradation; Comparative Example 9 (direct incineration): Organophosphorus was almost completely mineralized. Although the mineralization was thorough, it was energy-intensive and posed a high risk of secondary pollution, which contrasts sharply with the mild and resource-based approach of this application; Comparative Example 10 (hydrolysis + incineration): The effect was comparable to Example 2, but the cost and environmental pressure were far greater than the biochemical treatment approach of this application.

[0125] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0126] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for treating acephate waste liquid, characterized in that, The treatment method specifically includes the following steps: pretreatment, hydrolysis reaction, oxidation reaction, filtration, and wastewater treatment; The hydrolysis reaction involves adding a composite alkali agent to the pretreated waste liquid to carry out the hydrolysis reaction, thereby obtaining the hydrolyzed waste liquid; the composite alkali agent comprises 1-1.5 wt.% modified magnesium oxide and 4-8 wt.% calcium hydroxide; the amount of the composite alkali agent added is 3-5 times the weight of the pretreated waste liquid; the conditions for the hydrolysis reaction are: reaction temperature 50-60℃, reaction time 1.5-2.5h, and pH controlled at 10-12; The oxidation reaction involves adding calcium hypochlorite to the waste liquid after hydrolysis to carry out the oxidation reaction, thereby obtaining the material after the oxidation reaction; the molar ratio of the calcium hypochlorite to the residual hydrogen sulfide in the waste liquid after hydrolysis is controlled to be (1.2-1.5):1; The wastewater treatment involves using a wastewater treatment system to biochemically treat the filtered filtrate to obtain recycled water. The acephate waste liquid contains 60-80% acephate, 10-15% spermine, and 3-5% insoluble impurities.

2. The processing method according to claim 1, characterized in that, The effective chlorine content of the calcium hypochlorite is ≥65%.

3. The processing method according to claim 1, characterized in that, The conditions for the oxidation reaction are: reaction temperature 25-35℃; reaction time 1-2h.

4. The processing method according to claim 1, characterized in that, The composite alkali agent also includes 0.5-1 wt.% nano-hydroxyapatite.

5. The processing method according to claim 1, characterized in that, The hydrolysis reaction step is also equipped with an alkaline washing and absorption device to absorb the inert gas that overflows during the hydrolysis reaction.

6. The processing method according to claim 1, characterized in that, The treatment method further includes solidifying the residue generated from the pretreatment step and the filtration process; after the solidified residue meets the hazardous waste landfill control standards, it is disposed of in a landfill.

7. The processing method according to claim 1, characterized in that, The biochemical treatment includes anaerobic treatment and aerobic treatment.

8. The processing method according to claim 1, characterized in that, The recycled water is reused in the preparation of the composite alkali agent used in the hydrolysis reaction.

9. The processing method according to claim 1, characterized in that, The pretreatment involves filtering the acephate waste liquid to remove insoluble impurities and suspended solids.

10. The processing method according to claim 1, characterized in that, The filtration step involves using a filter press to filter the material after the oxidation reaction.

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