Method and apparatus for treating hazardous waste liquid

Abstract

This invention discloses a method for treating hazardous waste liquid, comprising the following steps: mixing the hazardous waste liquid to be treated with polyferric sulfate evenly and then subjecting it to electron beam irradiation. In this method, before electron beam irradiation, polyferric sulfate is added to the hazardous waste liquid to be treated, mixed evenly, and then directly subjected to irradiation. This allows the catalytic oxidation effect of the synergistic irradiation treatment to more thoroughly treat the pollutants in the wastewater, while requiring a smaller dosage of the reagent.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a method for treating high-concentration hazardous wastewater by electron beam irradiation and a treatment device based on this method. Background Technology

[0002] Currently, hazardous waste liquids are characterized by complex sources and compositions, high toxicity, and poor biodegradability, posing a significant threat. The safe, efficient, and scientific disposal of hazardous waste liquids generated during the disposal process has attracted widespread public attention.

[0003] The high-concentration waste liquid generated during the hazardous waste disposal process mainly comes from wastewater prepared for the waste heat boiler in the incineration workshop, washing wastewater in the incineration workshop, floor washing wastewater in the incineration workshop, vehicle washing wastewater, hazardous waste container washing wastewater, slag removal system drainage, and waste gas purification equipment drainage, etc. The production wastewater of the solvent recovery system mainly includes wastewater in the production unit area, equipment floor cleaning water, and wastewater washing drainage, etc.

[0004] Considering the unique nature of hazardous waste, the pollution load of its production wastewater is very high, and the water quality and quantity vary greatly, especially the content of toxic and harmful substances is high. It is difficult to achieve the required treatment effect using biological treatment technologies alone. Based on the characteristics of high-concentration hazardous wastewater, current domestic and international hazardous waste disposal wastewater treatment technologies mainly include physicochemical treatment, biochemical treatment processes, and combinations of these processes. Traditional pretreatment processes before biochemical treatment typically employ physicochemical treatment (consisting of flocculation, sedimentation, iron-carbon micro-electrolysis, Fenton oxidation, etc.). Its main characteristic is the treatment of high concentrations of organic pollutants and heavy metal ions in the wastewater using chemical agents. This treatment method is often limited by the quality of the chemical agents and the fluctuations in water quality and quantity, leading to changes in reaction conditions. Therefore, it is characterized by high treatment difficulty, high technical requirements, and high operating costs. Summary of the Invention

[0005] In view of this, in order to overcome the shortcomings of the prior art, the object of the present invention is to provide an improved method for treating hazardous waste liquid.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for treating hazardous waste liquid includes the following steps: mixing the hazardous waste liquid to be treated with polyferric sulfate evenly and then directly subjecting it to electron beam irradiation treatment. This method is particularly suitable for high-concentration hazardous waste liquids (generally, wastewater with a COD higher than 2000 mg / L is considered high-concentration wastewater).

[0008] According to some preferred embodiments of the present invention, electron beam irradiation is performed within 10 minutes after the hazardous waste liquid to be treated is uniformly mixed with polyferric sulfate. In some embodiments, irradiation is preferably performed within 30 seconds after the addition of polyferric sulfate.

[0009] According to some preferred embodiments of the present invention, the addition of polyferric sulfate is a solid addition, and the amount added is such that the concentration of polyferric sulfate in the system after mixing with the hazardous waste liquid to be treated is not higher than 200 mg / L.

[0010] According to some preferred embodiments of the present invention, the addition of polyferric sulfate is a liquid addition: the polyferric sulfate is prepared into a liquid with a concentration of 8-12% and then added to the hazardous waste liquid to be treated, and the amount added is such that the concentration of polyferric sulfate in the system after mixing with the hazardous waste liquid to be treated is not higher than 200 mg / L.

[0011] According to some preferred embodiments of the present invention, the parameters of the electron beam irradiation treatment are a 1.5 MeV electron accelerator, providing an irradiation beam current of 60 mA, irradiating the hazardous waste liquid to be treated, and an absorbed dose of 5 to 15 kGy.

[0012] The present invention also provides a treatment device based on the treatment method described above, including a wastewater storage tank, a feed pipe, an irradiation tank, a discharge pipe, and an irradiation device. The feed pipe connects the wastewater storage tank and the irradiation tank and is used to transport wastewater from the wastewater storage tank to the irradiation tank. The irradiation device is used to irradiate the wastewater in the irradiation tank.

[0013] According to some preferred embodiments of the invention, a shielding body is included, the irradiation tank is disposed within the shielding body, and the feed pipe and discharge pipe penetrate the shielding body.

[0014] According to some preferred embodiments of the present invention, the feed pipe includes a horizontal section and a U-shaped section, a material mixer is provided on the horizontal section, the U-shaped section penetrates the side wall of the shield, and one end of the U-shaped section is connected to one end of the horizontal section, and the other end of the U-shaped section is connected to the irradiation water tank.

[0015] According to some preferred embodiments of the invention, the horizontal height of the U-shaped segment is lower than the horizontal height of the horizontal segment.

[0016] According to some preferred embodiments of the present invention, the feed pipe is provided with a water pump for conveying wastewater from the wastewater storage tank to the horizontal section.

[0017] According to some preferred embodiments of the invention, the feed pipe is provided with a feed pump for conveying polyferric sulfate to the horizontal section.

[0018] According to some preferred embodiments of the invention, the discharge pipe is disposed directly below the irradiation tank, and the discharge pipe includes a vertical section and an inclined section that are interconnected.

[0019] Compared with existing traditional technologies, the advantages of the present invention are as follows: In the method for treating hazardous waste liquid of the present invention, before electron beam irradiation treatment of hazardous waste liquid, polyferric sulfate is added to the hazardous waste liquid to be treated, and after mixing evenly, irradiation treatment is carried out directly. This makes the catalytic oxidation effect of synergistic irradiation treatment more thorough in treating pollutants in the wastewater, and the dosage of added reagents is less. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic flowchart of the hazardous waste liquid treatment method in an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of the hazardous waste liquid treatment equipment in an embodiment of the present invention;

[0023] In the attached diagram: 1. Electron beam irradiation device; 2. Stainless steel irradiation water tank; 3. Electron beam radiation shield; 4. Material mixer; 5. Irradiation water pump; 6. Feed pipe; 61. Horizontal section; 62. U-shaped section; 7. Discharge pipe; 71. Vertical section; 72. Inclined section; 8. Suction pipe; 9. Wastewater storage tank. Detailed Implementation

[0024] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 should fall within the scope of protection of the present invention.

[0025] Hazardous wastewater generated during disposal not only exhibits characteristics of excessive heavy metals but also high organic matter concentrations and poor biodegradability. Traditional wastewater treatment processes struggle to effectively degrade and remove heavy metal ions and toxic pollutants from concentrated hazardous wastewater using low-concentration chemical agents. The primary objective of this invention is to improve the biodegradability of highly concentrated hazardous wastewater and, through the synergistic effect of a catalytic agent (polyferric sulfate), degrade and remove toxic and harmful high-molecular-weight organic substances and heavy metal ions from the water.

[0026] The basic principle of this invention is as follows:

[0027] While treating wastewater with electron beam irradiation, polyferric sulfate (PFLS) is added as a co-catalyst. The active ions, such as hydroxyl radicals generated by electron beam excitation of water molecules, react with PFLS. Colloidal particulate pollutants and heavy metal ions, destabilized by the electron beam, undergo various polymerization processes and catalytic irradiation effects through the nuclear hydroxyl complexes provided by PFLS. The relatively small, high-valence complex ions are attracted to the negatively charged colloidal particles and suspended solids in the raw water, entering the compact layer and compressing the electric double layer of the particles, lowering the zeta potential, and causing rapid destabilization and aggregation. The high-valence macromolecular complex ions provided by PFLS mainly contribute to the adsorption and neutralization of the charge of the colloidal particles and also contribute to interparticle aggregation during the electron beam irradiation process. Through the synergistic polymerization effect of electron beam irradiation and PFLS, the final effect of removing recalcitrant pollutants and heavy metal ions from the water is achieved.

[0028] Example 1 Processing Equipment

[0029] like Figure 2 As shown, the hazardous waste liquid treatment equipment in this embodiment includes a shield 3, a wastewater storage tank 9, an inlet pipe 6, an irradiation water tank 2, an outlet pipe 7, and an irradiation device 1. The wastewater storage tank 9 is equipped with a suction pipe 8. The inlet pipe 6 connects the suction pipe 8 and the irradiation water tank 2, used to transport the wastewater in the wastewater storage tank 9 to the irradiation water tank 2. The irradiation device 1 is used to irradiate the wastewater in the irradiation water tank 2. The irradiation device 1 is installed on top of the electron beam radiation shield 3; the irradiation water tank 2 is installed inside the electron beam radiation shield 3, located below the irradiation device 1; the inlet pipe 6 and the outlet pipe 7 penetrate the shield 3.

[0030] The feed pipe 6 includes a horizontal section 61 and a U-shaped section 62. A material mixer 4 is installed on the horizontal section 61. The U-shaped section 62 penetrates the side wall of the shield 3, with one end of the U-shaped section 62 connected to one end of the horizontal section 61, and the other end connected to the irradiation water tank 2. The horizontal height of the U-shaped section 62 is lower than that of the horizontal section 61. Through the combination of the material mixer 4 and the U-shaped pipe, the electron beam radiation is effectively shielded to prevent leakage, while simultaneously achieving thorough mixing of the synergistic agent (polyferric sulfate) and the waste liquid to be treated.

[0031] The discharge pipe 7 is located at the bottom of the irradiation tank 2, and its end extends to the outside of the electron beam radiation shield 3. The discharge pipe 7 includes an interconnected vertical section 71 and an inclined section 72. The vertical section 71 is located directly below the irradiation tank 2 and passes through the shield 3. The vertical section 71 and the inclined section 72 of the discharge pipe 7 improve the flowability of the treated water from the irradiation tank 2, reduce the risk of siltation, and also avoid the safety risk of electron beam radiation leaking to the outside of the shield 3 through the conventional straight discharge pipe 7.

[0032] In this embodiment, the wastewater in the wastewater storage tank 9 is formed by uniformly mixing the waste liquid to be treated with the synergistic agent polyferric sulfate. Therefore, the feed pipe 6 is equipped with a water pump 5 for transporting the wastewater in the wastewater storage tank 9 to the horizontal section 61, and the material mixer 4 achieves more uniform mixing.

[0033] In other embodiments, the wastewater in the wastewater storage tank 9 is only untreated waste liquid. In this case, the feed pipe 6 is also equipped with a feed pump for conveying polyferric sulfate to the horizontal section 61, and the two are mixed by the material mixer 4 and then conveyed to the irradiation tank 2 through the U-shaped section 62. This effectively reduces the mixing time, allowing the mixed wastewater to be quickly conveyed to the irradiation device for irradiation, thus improving the treatment effect.

[0034] Example 2 Processing Method

[0035] like Figure 1 and 2 As shown, this embodiment provides a method for treating hazardous waste liquid based on the method in Example 1, which is particularly suitable for treating high-concentration hazardous waste liquid (generally, wastewater with a COD higher than 2000 mg / L is called high-concentration wastewater), including the following steps: The hazardous waste liquid to be treated is mixed evenly with polyferric sulfate and then subjected to electron beam irradiation treatment. Specifically, the following steps are included:

[0036] Step S1: After the hazardous waste liquid to be treated is mixed evenly with polyferric sulfate, it is transported to the wastewater storage tank 9. In this embodiment, the polyferric sulfate is added as a solid, and the amount added is such that the concentration of polyferric sulfate in the system after mixing with the hazardous waste liquid to be treated is not higher than 200 mg / L.

[0037] In other embodiments, the addition of polyferric sulfate can be in the form of liquid addition: the polyferric sulfate is prepared into a liquid with a concentration of 8-12%, preferably 10%, and then added to the hazardous waste liquid to be treated. The amount added is such that the concentration of polyferric sulfate in the system after mixing with the hazardous waste liquid to be treated is not higher than 200 mg / L.

[0038] Step S2: The wastewater in the wastewater storage tank 9 is pumped to the feed pipe 6 using the feed pump and suction pipe 8. Under the action of the material mixer 4 in the horizontal section 61, the wastewater to be irradiated is thoroughly mixed with the co-catalyst (polyferric sulfate). In this embodiment, irradiation is preferably carried out within 30 seconds after the addition of polyferric sulfate, thanks to the action of the pump and material mixer.

[0039] Step S3: The wastewater mixed with the synergistic catalyst (polyferric sulfate) enters the stainless steel irradiation tank 2 through the U-shaped inlet pipe for electron beam irradiation treatment. The U-shaped pipe design ensures that electron beam leakage is effectively avoided while achieving thorough mixing of the synergistic catalyst and the wastewater to be treated.

[0040] Step S4: The wastewater entering the stainless steel irradiation tank 2 is treated by irradiation with a high-energy electron beam.

[0041] Electron beam irradiation treatment uses a 1.5 MeV electron accelerator to provide an irradiation beam current of 60 mA to irradiate the hazardous waste liquid to be treated, with an absorbed dose of 5–15 kGy.

[0042] When water is exposed to ionizing radiation, ionized and excited water molecules and free electrons react rapidly to form reactive free radicals (e.g., ionized and excited water molecules and free electrons). aq -Electron beam irradiation (EMI) produces various redox reactions with recalcitrant organic matter in wastewater, including products such as H₂, OH₂, H₂O₂, etc., ultimately effectively decomposing toxic and harmful substances such as high-molecular-weight organic matter, thereby improving the biodegradability of wastewater. Simultaneously with wastewater treatment, polyferric sulfate (PFLS) is added as a co-catalyst. The active ions, such as hydroxyl radicals generated by electron beam excitation of water molecules, react with PFLS. Colloidal particulate pollutants and heavy metal ions, destabilized by the electron beam, undergo various polymerization processes and catalytic irradiation effects through the nuclear hydroxyl complexes provided by PFLS. The relatively small molecular weight of the high-valence complex ions is attracted to the compact layer of negatively charged colloidal particles and suspended solids in the raw water, compressing the double layer of the colloidal particles and lowering the zeta potential, causing the particles to rapidly destabilize and precipitate. The high-valence macromolecular complex ions provided by the synergistic catalyst polyferric sulfate adsorb and neutralize the charge of colloidal particles and also contribute to interparticle aggregation during electron beam irradiation synergistic treatment. The dosage of the synergistic catalyst polyferric sulfate generally varies depending on the quality of the treated water. As described in step S1, for high-concentration hazardous wastewater (generally defined as wastewater with a COD higher than 2000 mg / L), the dosage for electron beam synergistic treatment can be determined appropriately based on the properties of the raw water through production debugging or beaker experiments. Under normal circumstances, the solid dosage should not exceed 200 mg / L, and the liquid dosage can be prepared using tap water at a 10% concentration, confirmed by referring to the solid dosage method. Through the synergistic polymerization of polyferric sulfate under electron beam irradiation, the effect of removing recalcitrant pollutants and heavy metal ions from the water body is ultimately achieved.

[0043] Step S5: Discharge the irradiated wastewater to the subsequent treatment process section or to the outlet through the discharge pipe 7. The vertical section 71 and the inclined section 72 of the discharge pipe 7 not only improve the flowability of the treated water from the irradiation tank 2 and reduce the risk of siltation, but also avoid the safety risk of electron beam rays leaking to the outside of the shield 3 through the conventional straight discharge pipe 7.

[0044] Comparative Example 1

[0045] The difference between this comparative example and Example 2 is that the wastewater transported to the irradiation tank 2 in this comparative example is only the waste liquid to be treated, and no synergistic agent, polyferric sulfate, is added. The other steps and parameters are basically the same as in Example 2.

[0046] Comparative Example 2

[0047] The difference between this comparative example and Example 2 is that the wastewater transported to the irradiation tank 2 in this comparative example is only the waste liquid to be treated, and no synergistic agent, polyferric sulfate, is added. Polyferric sulfate is added to the system after the irradiation treatment is completed. The other steps and parameters are basically the same as in Example 2.

[0048] Tests and Results

[0049] The following tests were conducted on the original hazardous waste liquid, the hazardous waste liquid after adding polyferric sulfate, and the liquid after treatment according to Example 2, Comparative Example 1, or Comparative Example 2:

[0050] Table 1 Test Results

[0051]

[0052]

[0053] The results in the table above show that: the raw water has a high COD concentration and a B / C ratio below 0.1; when polyferric sulfate is added alone to the hazardous waste liquid to be treated, the COD organic pollutant removal rate is about 35% and the B / C ratio is 0.12; in Comparative Example 1, the waste liquid to be treated was irradiated alone, and the COD organic pollutant removal rate was about 40% and the B / C ratio was 0.20; in Comparative Example 2, the original hazardous waste liquid was irradiated and then polyferric sulfate was added, and the COD organic pollutant removal rate was about 50% and the B / C ratio was 0.24; in Example 2, the original hazardous waste liquid was treated with a synergistic combination of polyferric sulfate and irradiation, and the COD organic pollutant removal rate was 55% and the B / C ratio was 0.33, which is significantly better than that of the comparative examples.

[0054] The electron beam irradiation treatment equipment for high-concentration hazardous wastewater provided by the present invention includes: an irradiation device 1 located on top of a stainless steel irradiation tank 2; the stainless steel irradiation tank 2 placed inside an electron beam radiation shield 3; wastewater to be treated collected in a wastewater storage tank 9 located outside the radiation shield 3 is lifted and transported to a material mixer 4 in the feed pipeline by an inlet pump 5 located at the top of the wastewater storage tank 9 and an inlet pump suction pipe 8 inside the wastewater storage tank 9; then the wastewater to be treated is transported to the stainless steel irradiation tank 2 through a U-shaped section 6; finally, the irradiated wastewater is discharged to a subsequent treatment process section or discharged through a discharge pipe 7 located at the bottom of the stainless steel irradiation tank 2.

[0055] To prevent the radioactive electron beam generated within the electron beam radiation shield 3 from leaking into the external environment and posing a radiation safety hazard through the externally connected inlet and outlet pipes, a U-shaped section is installed on the inlet pipe, and a vertical and inclined section is installed on the outlet pipe. The high-concentration wastewater to be treated is transported through the irregular connection and transmission of the U-shaped inlet pipe and Z-shaped outlet pipe, allowing the wastewater to undergo a full and synergistic catalytic reaction with electron beam irradiation and polyferric sulfate. This reduces the risk of siltation in the treated water pipes and also avoids the safety risk of electron beam radiation leaking outside the shield through conventional straight inlet and outlet pipes.

[0056] The electron beam irradiation treatment equipment and synergistic method for treating high-concentration hazardous wastewater provided by this invention utilizes an irradiation treatment device capable of generating high-energy electron beams to treat high-concentration wastewater. This allows for the rapid reaction of ionized and excited water molecules and free electrons generated when water is subjected to ionizing radiation to form active free radicals (e.g., electron beams). aq - The product (such as ·H, ·OH, H2, H2O2, etc.) undergoes various redox reactions with recalcitrant organic matter in wastewater, effectively breaking down and severing the chains of large organic molecules in the water, transforming them into biodegradable small molecules. This effectively removes toxicity from the water and improves its biodegradability. Furthermore, with the synergistic effect of the polyferric sulfate catalyst, it removes heavy metal ions from the water. A U-shaped inlet pipe and a Z-shaped outlet pipe are used to transport the high-concentration wastewater, ensuring thorough irradiation while minimizing the risk of electron beam leakage from the shielding. The effluent treated with polyferric sulfate and electron beam irradiation is then combined with traditional biochemical processes to ultimately remove pollutants from the water.

[0057] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for treating hazardous waste liquid, wherein the COD of the hazardous waste liquid is higher than 2000 mg / L, characterized in that: Hazardous waste liquid is treated using a treatment device, which includes a wastewater storage tank, an inlet pipe, an irradiation tank, an outlet pipe, and an irradiation device. The inlet pipe connects the wastewater storage tank and the irradiation tank and is used to transport wastewater from the wastewater storage tank to the irradiation tank. The irradiation device is used to irradiate the wastewater in the irradiation tank. The system includes a shielding body, with the irradiation water tank housed within the shielding body. An inlet pipe and an outlet pipe penetrate the shielding body. The inlet pipe comprises a horizontal section and a U-shaped section. A material mixer is mounted on the horizontal section. The U-shaped section penetrates the side wall of the shielding body, with one end connected to one end of the horizontal section and the other end connected to the irradiation water tank. The outlet pipe is located directly below the irradiation water tank and comprises a vertical section and an inclined section that are interconnected. The vertical section penetrates the shielding body, and the horizontal height of the U-shaped section is lower than the horizontal height of the horizontal section. The treatment method includes the following steps: after uniformly mixing the hazardous waste liquid to be treated with polyferric sulfate, electron beam irradiation treatment is carried out; specifically, irradiation is carried out within 30 seconds after adding polyferric sulfate; the active ions generated by the electron beam excitation of water molecules undergo a chemical reaction with the synergistic catalytic agent polyferric sulfate, and the colloidal particulate pollutants and heavy metal ions formed after being destabilized by the electron beam in the water body undergo multiple polymerization and catalytic irradiation effects through the nucleohydroxy complexes of multiple components provided by polyferric sulfate.

2. The processing method according to claim 1, characterized in that: The addition of polyferric sulfate is a solid addition, and the amount added is such that the concentration of polyferric sulfate in the system after mixing with the hazardous waste liquid to be treated is not higher than 200 mg / L.

3. The processing method according to claim 1, characterized in that: The addition of polyferric sulfate is a liquid addition: the polyferric sulfate is prepared into a liquid with a concentration of 8~12% and then added to the hazardous waste liquid to be treated. The amount added is such that the concentration of polyferric sulfate in the system after mixing with the hazardous waste liquid to be treated is not higher than 200mg / L.

4. The processing method according to claim 1, characterized in that: The feed pipe is equipped with a water pump for conveying wastewater from the wastewater storage tank to the horizontal section; and / or, the feed pipe is equipped with a feed pump for conveying polyferric sulfate to the horizontal section.

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