Sewage treatment process for organic wastewater

Abstract

The invention discloses a sewage treatment process for organic wastewater, and belongs to the field of sewage treatment.The sewage treatment process comprises the following steps that S1, wastewater containing nitrogen-containing organic phosphonic acid metal complexes is pumped into a dielectric barrier discharge reactor, and P-C bond energy is reduced through high-energy electron bombardment; s2, adding a modified layered metal hydroxide containing interlayer co-intercalation carbon quantum dots and persulfate and a composite oxidant of aspergillus niger immobilized microspheres into the wastewater subjected to plasma treatment; s3, deeply adsorbing heavy metal ions in the wastewater subjected to composite oxidation treatment in a gradient magnetic field by utilizing a magnetic layered metal hydroxide material; s4, the wastewater subjected to magnetic adsorption sequentially passes through an anaerobic ammonia oxidation coupling reactor and an aerobic biological membrane-activated sludge system to degrade pollutants; s5, dephosphorizing the wastewater subjected to biological treatment by algae by adopting a layered immobilized phycomycete symbiotic system; and S6, tail end magnetic recovery and effluent disinfection. The invention aims to solve the problems of low decomplexing efficiency and halfway decomplexing in the prior art.

Description

Technical Field

[0001] The invention belongs to the field of wastewater treatment and relates to a sewage treatment process for organic wastewater. Background Art

[0002] Complex heavy metals are heavy metal wastewaters that are more difficult to treat. Since the existence of pollutants in complex heavy metal wastewater is relatively complex, the current main treatment technology is to break the complex first and then use conventional methods to treat it. Therefore, it is necessary to coordinate the use of multiple methods and processes to comprehensively treat the wastewater, such as using redox or electrochemical methods to first break the complex pretreatment, and then use chemical precipitation and membrane separation methods to further reduce the heavy metal content. These processes are more commonly used in practice.

[0003] However, in the organic wastewater containing nitrogen-containing organophosphonic acid metal complexes, due to the high PC bond energy in the organic phosphonic acid, conventional oxidation (such as Fenton and ozone) is difficult to effectively break, resulting in incomplete decomplexation. In addition, the existing subsequent chemical precipitation method, membrane separation and other methods have relatively low removal rates for heavy metals, nitrogen and phosphorus. There is a lack of treatment processes that can efficiently treat organic wastewater containing nitrogen-containing organophosphonic acid metal complexes. Summary of the Invention

[0004] The purpose of the present invention is to provide a sewage treatment process for organic wastewater, which solves the problem of the lack of a treatment process for organic wastewater containing nitrogen-containing organophosphonic acid metal complexes.

[0005] The technical solution adopted in the present invention is as follows:

[0006] A sewage treatment process for organic wastewater, comprising the following steps:

[0007] S1. Plasma pretreatment: The wastewater containing nitrogen-containing organophosphonic acid metal complexes is pumped into a dielectric barrier discharge reactor, where high-energy electron bombardment is used to reduce the PC bond energy to 180-190 kJ / mol, and the effluent ORP is controlled at 150-200 mV.

[0008] S2. Composite oxidation treatment: adding a composite oxidant comprising a modified layered metal hydroxide containing co-intercalated carbon quantum dots and persulfate and Aspergillus niger immobilized microspheres to the wastewater after plasma treatment, and controlling alkaline conditions for oxidative decomplexation;

[0009] S3. Magnetic adsorption: Using magnetic layered metal hydroxide materials to deeply adsorb heavy metal ions in wastewater after composite oxidation treatment under a gradient magnetic field;

[0010] S4. Biological treatment: The wastewater after magnetic adsorption passes through the anaerobic ammonium oxidation coupled reactor and the aerobic biofilm-activated sludge system in sequence to degrade pollutants;

[0011] S5. Algae-bacteria symbiotic treatment: A layered immobilized algae-bacteria symbiotic system is used to remove phosphorus from the biologically treated wastewater;

[0012] S6, terminal magnetic recovery and effluent disinfection.

[0013] The present invention aims to solve the problems of low efficiency and incomplete decomplexation in the prior art. First, before oxidative decomplexation, the wastewater is subjected to plasma pretreatment. Dielectric barrier discharge generates high-energy electrons, which bombard the organic phosphonic acid molecules in the wastewater, reducing the PC bond energy to 180-190 kJ / mol. At the same time, the redox potential (ORP) is increased to 150-200 mV, creating active groups (·OH, SO4· - ) generation conditions, the prior art PC bond energy is high, requires a high oxidant dose, and the decomplexation is not complete;

[0014] Secondly, the present application adopts a composite oxidant to achieve decomplexation. The present application uses a modified layered metal hydroxide containing interlayer co-intercalated carbon quantum dots and persulfate as the core material, provides an interlayer reaction site, and replaces the existing liquid phase reaction; the interlayer reaction has the effect of interlayer confined oxidation, and the modified layered metal hydroxide channel forces the nitrogen-containing organic phosphonic acid metal complex to be in close contact with the persulfate and collide frequently, and the interlayer persulfate achieves concentration enrichment, which is several times higher than the concentration dispersed in the solution, and the interlayer structure can separate some impurities, reducing the degree of interference with the oxidation reaction, and achieving the decomposition of the organic phosphonic acid metal complex. Efficient oxidative decomplexation; The present application uses layered metal hydroxides as components that provide interlayer reactions. In addition to having a layered structure, it can also capture heavy metal ions and phosphates after decomplexation between layers; The principle of decomplexation in the present application is: under alkaline conditions, persulfate is activated to generate sulfate radicals, which preferentially attack weakened PC bonds to achieve the purpose of decomplexation; and carbon quantum dots have a free radical capture effect, and the adsorption effect of the π electron cloud causes sulfate radicals to form a high-concentration area on its surface, thereby achieving the enrichment of sulfate radicals between layers, increasing the collision frequency between free radicals and PC bonds, and contributing to the realization of efficient decomplexation between layers. The present invention reduces the pH of the oxidizing environment by reducing bond energy and utilizing interlayer reactions. It does not require a strong alkaline environment, and can achieve oxidative decomplexation in a weak alkaline environment close to neutral.

[0015] However, due to the intercalation modification of the layered metal hydroxide, the interlayer spacing is increased. During the dynamic reaction of decomplexation, some free heavy metal ions will escape from the interlayer structure. When the concentration of heavy metal ions in the wastewater outside the interlayer increases significantly, the free heavy metal ions are easily secondary complexed by the residual organic phosphonic acid in the wastewater to form a stable complex, which is difficult to remove. Therefore, in order to reduce the concentration of free heavy metals in the wastewater, the present application adds Aspergillus niger immobilized microspheres, which adsorb free heavy metal ions, such as Cu 2+, in real time. 2+ , secreting oxalic acid to degrade organic phosphonic acid residues, blocking secondary complexation, and being used as a "trap" for free heavy metals in the liquid phase. Aspergillus niger produces oxalic acid in a nearly neutral environment. Therefore, in order to avoid the impact of the oxidizing weak alkaline environment on Aspergillus niger, the present application utilizes the porous adsorption effect of the microsphere structure to adsorb oxalic acid and reduce the local pH at the location of the microspheres. Since the pH of the overall wastewater environment is a weak alkaline environment, the local pH at the location of the microspheres is less affected, so that the Aspergillus niger microspheres maintain a neutral environment capable of producing oxalic acid; the porous structure of the microspheres also facilitates the overflow of oxalic acid from the microspheres.

[0016] Furthermore, the composite oxidant in step S2 comprises the following components in parts by weight: 60-65 parts of modified Zn-Mg-Al LDH containing interlayer co-intercalated carbon quantum dots and persulfate, 25-30 parts of Aspergillus niger immobilized microspheres, and a pH regulator; the dosage of the composite oxidant is 0.5-1.5% g / m of the wastewater volume. 3 .

[0017] The present invention proposes a specific implementation scheme for limiting layered metal hydroxides based on current actual usage conditions.

[0018] Furthermore, the organophosphonic acid metal complex includes a Cu-ATMP complex, and the Aspergillus niger immobilized microspheres are obtained by the following preparation method:

[0019] A1. Aspergillus niger in the presence of ATMP and Cu 2+ Cultured in a culture medium for 72 hours to obtain mycelium;

[0020] B1, mixing mycelium with sodium alginate and Fe3O4 nanoparticles, and dropping them into CaCl2 solution to form magnetic gel microspheres;

[0021] C1. Surface modification of magnetic gel microspheres was performed using polyethyleneimine to obtain Aspergillus niger immobilized microspheres.

[0022] The present invention is mainly used for wastewater containing nitrogenous organic phosphonic acid copper ion complex, and Aspergillus niger is used for wastewater containing ATMP and Cu 2+ In the culture medium for 72 hours, the concentration of ATMP was 0.5-1mM, and Cu2+ The concentration is 0.5-2mM.

[0023] Furthermore, the modified Zn-Mg-Al LDH is prepared by the following method:

[0024] A2. Using zinc nitrate, magnesium nitrate, and aluminum nitrate as metal sources, a Zn-Mg-Al LDH precursor was synthesized by coprecipitation reaction under alkaline conditions; the CQDs dispersion, sodium persulfate, and LDH precursor were mixed;

[0025] B2. Reaction under alkaline hydrothermal conditions to obtain interlayer co-intercalated carbon quantum dots and persulfate Zn-Mg-AlLDH, wherein the mass ratio of CQDs to sodium persulfate is 1:1-3;

[0026] C2. A mesoporous SiO2 shell is formed on the surface of Zn-Mg-Al LDH with interlayer co-intercalated carbon quantum dots and persulfate by a sol-gel method to obtain a modified Zn-Mg-Al LDH containing interlayer co-intercalated carbon quantum dots and persulfate.

[0027] Furthermore, the mass ratio of Zn, Mg and Al in the modified Zn-Mg-Al LDH is 0.2:3:1.

[0028] Furthermore, the preparation method of the magnetic layered metal hydroxide material in step S3 is: using Zn-Mg-Al LDH to load on a magnetic fluidized bed adsorption tower, the Zn-Mg-Al LDH particle size is 50-100 μm, and the specific surface area is ≥80 m2 / g to obtain a magnetic layered double metal hydroxide material.

[0029] A gradient magnetic field is applied in the adsorption tower. The magnetic field force causes the magnetic components of the bed (Fe□O□ or carrier) to be oriented, driving the loaded LDH particles to be evenly suspended (fluidized) in the wastewater, thereby increasing the contact area with heavy metal ions.

[0030] Furthermore, the magnetic field gradient is achieved by a permanent magnet array with an inlet of 0.3T and an outlet of 0.5T.

[0031] Furthermore, the layered immobilized algae-bacteria symbiotic system in step S5 includes a photobioreactor structure, the upper layer of the photobioreactor structure includes an immobilized Chlorella biofilm, and the immobilized Chlorella biofilm is embedded in a sodium alginate-activated carbon carrier; the lower layer of the photobioreactor structure includes an aerobic bacterial biofilm, and the bacterial community includes nitrifying bacteria and polyphosphate bacteria.

[0032] Furthermore, in step S6, the terminal magnetic recovery uses Fe3O4@diatomaceous earth to separate and recover the magnetic materials in the terminal wastewater.

[0033] Furthermore, in step S6, a 254 nm ultraviolet disinfection system is used to disinfect the wastewater.

[0034] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0035] 1. A wastewater treatment process for organic wastewater addresses the core issue of organophosphonic acid complexes being difficult to decomplex and prone to complexation through plasma pretreatment, interlayer confined oxidation, and biological synergy. Combined with magnetic separation and algae-bacteria symbiosis, it also achieves deep removal of heavy metals, phosphorus, and nitrogen, meeting the discharge requirements for wastewater containing nitrogen-containing organophosphonic acid metal complexes.

[0036] 2. The present invention utilizes plasma pretreatment and interlayer confined oxidation to lower the pH for decomplexation. At this pH, combined with the effect of the microspheres, the microspheres are modified with positive charges of polyethyleneimine, and the microsphere surfaces can effectively adsorb oxalate anions, achieving a low pH at the microspheres that meets the pH requirement for oxalic acid production by Aspergillus niger.

[0037] 3. The magnetic LDH combined with the gradient magnetic field in the present invention can achieve deep removal of heavy metal ions, and the removal rate is much higher than that of traditional adsorption materials (such as activated carbon). BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be considered as limiting the scope. A person of ordinary skill in the art can also derive other relevant drawings based on these drawings without inventive effort, among which:

[0039] Figure 1 It is a process flow chart of a sewage treatment process for organic wastewater;

[0040] Figure 2 is a TEM image of Aspergillus niger immobilized microspheres. DETAILED DESCRIPTION

[0041] In order to make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present invention and are not intended to limit the present invention. That is, the embodiments described herein are only some embodiments of the present invention, not all embodiments. Generally, the components of the embodiments of the present invention described and illustrated in the drawings herein may be arranged and designed in various different configurations.

[0042] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but is merely intended to represent selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0043] It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0044] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0045] Example 1

[0046] like Figure 1 As shown, a sewage treatment process for organic wastewater provided by a preferred embodiment of the present invention comprises the following steps:

[0047] S1. Plasma pretreatment: The wastewater containing nitrogen-containing organophosphonic acid metal complexes is pumped into a dielectric barrier discharge reactor (power 300W, residence time 10-15min), and the PC bond energy is reduced to 180-190kJ / mol through high-energy electron bombardment, and the effluent ORP is controlled at 150-200mV;

[0048] S2. Composite oxidation treatment: adding a composite oxidant comprising a modified layered metal hydroxide containing co-intercalated carbon quantum dots and persulfate and Aspergillus niger immobilized microspheres to the wastewater after plasma treatment, and controlling the alkaline conditions for oxidation decomplexation at a pH of 8-8.5;

[0049] S3. Magnetic adsorption: Using magnetic layered metal hydroxide materials to deeply adsorb heavy metal ions in the filtered wastewater after composite oxidation treatment under a gradient magnetic field;

[0050] S4. Biological treatment: The wastewater after magnetic adsorption passes through the anaerobic ammonium oxidation coupled reactor and the aerobic biofilm-activated sludge system in sequence to degrade pollutants;

[0051] S5. Algae-bacteria symbiotic treatment: A layered immobilized algae-bacteria symbiotic system is used to remove phosphorus from the biologically treated wastewater;

[0052] S6, terminal magnetic recovery and effluent disinfection.

[0053] The composite oxidant in step S2 comprises the following components in parts by weight: 60 parts of modified Zn-Mg-Al LDH containing interlayer co-intercalated carbon quantum dots and persulfate, 25 parts of Aspergillus niger immobilized microspheres, and a pH regulator; the addition amount of the composite oxidant is 1.5% g / m3 of the wastewater volume. 3 .

[0054] The organic phosphonic acid metal complex in the wastewater containing nitrogen organic phosphonic acid metal complex mainly includes Cu-ATMP complex, the total copper ion concentration in the wastewater is 100-200 mg / L, and the ATMP concentration is 200-350 mg / L. The Aspergillus niger immobilized microspheres are obtained by the following preparation method:

[0055] A1. Aspergillus niger in the presence of ATMP and Cu 2+ Cultured in a culture medium for 72 hours to obtain mycelium;

[0056] B1, mixing mycelium with sodium alginate solution and Fe3O4 nanoparticles to form a suspension, and dropping it into CaCl2 solution to form magnetic gel microspheres;

[0057] C1. Surface modification of magnetic gel microspheres was performed using polyethyleneimine to obtain Aspergillus niger immobilized microspheres.

[0058] The dosage of mycelium, sodium alginate, and Fe3O4 is as follows: 10 g mycelium, 50 ml sodium alginate solution (the concentration of the sodium alginate solution is 4% w / v) per 100 mL of suspension, and the dosage of Fe3O4 relative to the sodium alginate solution is 2% w / v; the TEM image of the Aspergillus niger immobilized microspheres is shown in FIG. Figure 2 shown.

[0059] The modified Zn-Mg-Al LDH is prepared by the following method:

[0060] A2. Using zinc nitrate, magnesium nitrate, and aluminum nitrate as metal sources, a Zn-Mg-Al LDH precursor was synthesized by coprecipitation reaction under alkaline conditions; the CQDs dispersion, sodium persulfate, and LDH precursor were mixed;

[0061] B2. Reaction under alkaline hydrothermal conditions to obtain interlayer co-intercalated carbon quantum dots and persulfate Zn-Mg-AlLDH, wherein the mass ratio of CQDs to sodium persulfate is 1:1-3;

[0062] C2. A mesoporous SiO2 shell is formed on the surface of Zn-Mg-Al LDH with interlayer co-intercalated carbon quantum dots and persulfate by a sol-gel method to obtain a modified Zn-Mg-Al LDH containing interlayer co-intercalated carbon quantum dots and persulfate.

[0063] The mass ratio of Zn, Mg and Al in the modified Zn-Mg-Al LDH is 0.2:3:1.

[0064] The preparation method of the magnetic layered metal hydroxide material in step S3 is: using Zn-Mg-Al LDH to load on a magnetic fluidized bed adsorption tower, the Zn-Mg-Al LDH particle size is 50-100 μm, and the specific surface area is ≥80 m2 / g to obtain a magnetic layered double metal hydroxide material.

[0065] The magnetic field gradient is achieved by a permanent magnet array with an inlet of 0.3 T and an outlet of 0.5 T.

[0066] The layered immobilized algae-bacteria symbiotic system in step S5 includes a photobioreactor structure, wherein the upper layer of the photobioreactor structure includes an immobilized Chlorella biofilm, and the immobilized Chlorella biofilm is embedded in a sodium alginate-activated carbon carrier; and the lower layer of the photobioreactor structure includes an aerobic bacterial biofilm, and the bacterial community includes nitrifying bacteria and polyphosphate bacteria.

[0067] In step S6, the terminal magnetic recovery uses Fe3O4@diatomaceous earth to separate and recover the magnetic materials in the terminal wastewater.

[0068] In step S6, a 254 nm ultraviolet disinfection system is used to disinfect the wastewater.

[0069] Example 2

[0070] In this embodiment, based on the embodiment 1, the composite oxidant in step S2 comprises the following components in parts by weight: 63 parts of modified Zn-Mg-Al LDH containing interlayer co-intercalated carbon quantum dots and persulfate, 28 parts of Aspergillus niger immobilized microspheres, and a pH regulator; the addition amount of the composite oxidant is 0.8% g / m 2 of the wastewater volume. 3 .

[0071] Example 3

[0072] In this embodiment, based on the embodiment 1, the composite oxidant in step S2 comprises the following components in parts by weight: 65 parts of modified Zn-Mg-Al LDH containing interlayer co-intercalated carbon quantum dots and persulfate, 30 parts of Aspergillus niger immobilized microspheres, and a pH regulator; the dosage of the composite oxidant is 0.5% g / m3 of the wastewater volume. 3 .

[0073] Comparative Example 1

[0074] Based on Example 2, this comparative example is different from Example 2 in that the plasma pretreatment in step S1 is not performed in this comparative example, and water treatment is performed directly from step S2.

[0075] Comparative Example 2

[0076] Based on Example 2, this comparative example is different from Example 2 in that the composite oxidant of this comparative example does not contain Aspergillus niger immobilized microspheres.

[0077] Comparative Example 3

[0078] Based on Example 2, the difference between this comparative example and Example 2 is that the steps of this comparative example S2 are as follows: persulfate and Aspergillus niger immobilized microspheres are directly added to the wastewater after plasma treatment, modified Zn-Mg-Al LDH is not used, alkaline conditions are controlled for oxidative decomplexation, and the pH needs to be greater than 10.

[0079] Comparative Example 4

[0080] Based on Example 2, this comparative example is different from Example 2 in that the modified Zn-Mg-Al LDH in the composite oxidant of this comparative example is only modified by persulfate intercalation, and no carbon quantum dots are added.

[0081] Comparative Example 5

[0082] Based on Example 2, this comparative example is different from Example 2 in that Aspergillus niger is directly added to the composite oxidant in this comparative example instead of being added in the form of microspheres.

[0083] Comparative Example 6

[0084] Based on Example 2, this comparative example is different from Example 2 in that step S3, magnetic adsorption, is not performed in this comparative example.

[0085] Comparative Example 7

[0086] Based on Example 2, this comparative example is different from Example 2 in that S4 and biological treatment are not performed in this comparative example.

[0087] Comparative Example 8

[0088] Based on Example 2, this comparative example is different from Example 2 in that S5 and algae-bacteria symbiosis treatment are not performed in this comparative example.

[0089] Comparative Example 9

[0090] Based on Example 2, this comparative example is different from Example 2 in that S6, terminal magnetic recovery and effluent disinfection are not performed in this comparative example.

[0091] Comparative Example 10

[0092] Based on Example 2, this comparative example is different from Example 2 in that the modified Zn-Mg-Al LDH in this comparative example is prepared by the following method:

[0093] A2. Using zinc nitrate, magnesium nitrate, and aluminum nitrate as metal sources, a Zn-Mg-Al LDH precursor was synthesized by coprecipitation reaction under alkaline conditions; the CQDs dispersion, sodium persulfate, and LDH precursor were mixed;

[0094] B2. Zn-Mg-AlLDH with co-intercalated carbon quantum dots and persulfate was obtained by reaction under alkaline hydrothermal conditions, wherein the mass ratio of CQDs to sodium persulfate was 1:0.5;

[0095] C2. A mesoporous SiO2 shell is formed on the surface of Zn-Mg-Al LDH with interlayer co-intercalated carbon quantum dots and persulfate by a sol-gel method to obtain a modified Zn-Mg-Al LDH containing interlayer co-intercalated carbon quantum dots and persulfate.

[0096] Comparative Example 11

[0097] Based on Example 2, this comparative example is different from Example 2 in that the modified Zn-Mg-Al LDH in this comparative example is prepared by the following method:

[0098] A2. Using zinc nitrate, magnesium nitrate, and aluminum nitrate as metal sources, a Zn-Mg-Al LDH precursor was synthesized by coprecipitation reaction under alkaline conditions; the CQDs dispersion, sodium persulfate, and LDH precursor were mixed;

[0099] B2. Zn-Mg-AlLDH with co-intercalated carbon quantum dots and persulfate was obtained by reaction under alkaline hydrothermal conditions, wherein the mass ratio of CQDs to sodium persulfate was 1:4;

[0100] C2. A mesoporous SiO2 shell is formed on the surface of Zn-Mg-Al LDH with interlayer co-intercalated carbon quantum dots and persulfate by a sol-gel method to obtain a modified Zn-Mg-Al LDH containing interlayer co-intercalated carbon quantum dots and persulfate.

[0101] Comparative Example 12

[0102] Based on Example 2, this comparative example is different from Example 2 in that the Aspergillus niger immobilized microspheres in this comparative example are not modified with polyethyleneimine.

[0103] Comparative Example 13

[0104] Based on Example 2, this comparative example differs from Example 2 in that the modified Zn-Mg-Al LDH in this comparative example is not modified with mesoporous silica, but is prepared by the following method:

[0105] A2. Using zinc nitrate, magnesium nitrate, and aluminum nitrate as metal sources, a Zn-Mg-Al LDH precursor was synthesized by coprecipitation reaction under alkaline conditions; the CQDs dispersion, sodium persulfate, and LDH precursor were mixed;

[0106] B2. Zn-Mg-AlLDH with co-intercalated carbon quantum dots and persulfate was obtained by reaction under alkaline hydrothermal conditions, wherein the mass ratio of CQDs to sodium persulfate was 1:1-3.

[0107] Test Example 1

[0108] Take the wastewater containing Cu-ATMP complex (Cu 2+ 150mg / L, ATMP 300mg / L), according to the process of Examples 1-3 and Comparative Examples 1-13, the pH range of the decomplexation in the composite oxidation stage and the residual Cu in the water after treatment were determined. 2+ The concentration and ATMP concentration are used to calculate the removal rate. The above method is the existing technology. The test results are shown in Table 1.

[0109] Table 1 Pollutant removal rate

[0110]

[0111]

[0112] Test Example 2

[0113] Based on the water sample of Test Example 1, the COD, TN, TP and total bacteria count of the effluent of Examples 1-3 and Comparative Examples 1-13 were measured using the existing technology. The results are shown in Table 2.

[0114] Table 2 Comprehensive indicators of effluent

[0115]

[0116]

[0117] According to the data comparison of Table 1 and Table 2, the sewage treatment process of the present invention has good effects on decomplexation efficiency, pollutant removal rate and effluent water quality. The present invention solves the problem of difficult decomplexation and easy complexation of organic phosphonic acid complexes through plasma pretreatment, interlayer confined oxidation, biological synergy, etc., while achieving deep removal of heavy metals, nitrogen and phosphorus, and the effluent indicators are comprehensively better than traditional processes. Example 2 is the best solution. In addition to pollutants such as nitrogen-containing organic phosphonic acid metal complexes, organic wastewater generally also contains other organic pollutants. Therefore, the present invention adopts a multi-step collaborative treatment.

[0118] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions and improvements made by any technician familiar with the field within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A sewage treatment process for organic wastewater, characterized in that: The following steps are involved: S1. Plasma pretreatment: The wastewater containing nitrogen-containing organic phosphonic acid metal complexes is pumped into a dielectric barrier discharge reactor. The PC bond energy is reduced to 180-190 kJ / mol through high-energy electron bombardment, and the effluent ORP is controlled at 150-200 mV. S2. Composite oxidation treatment: adding a composite oxidant comprising a modified layered metal hydroxide containing co-intercalated carbon quantum dots and persulfate and Aspergillus niger immobilized microspheres to the wastewater after plasma treatment, and controlling alkaline conditions for oxidative decomplexation; S3. Magnetic adsorption: Using magnetic layered metal hydroxide materials to deeply adsorb heavy metal ions in wastewater after composite oxidation treatment under a gradient magnetic field; S4. Biological treatment: The wastewater after magnetic adsorption passes through the anaerobic ammonium oxidation coupled reactor and the aerobic biofilm-activated sludge system in sequence to degrade pollutants; S5. Algae-bacteria symbiotic treatment: A layered immobilized algae-bacteria symbiotic system is used to remove phosphorus from the biologically treated wastewater; S6, terminal magnetic recovery and effluent disinfection.

2. A sewage treatment process for organic wastewater according to claim 1, characterized in that: The composite oxidant in step S2 comprises the following components in parts by weight: 60-65 parts of modified Zn-Mg-Al LDH containing interlayer co-intercalated carbon quantum dots and persulfate, 25-30 parts of Aspergillus niger immobilized microspheres, and a pH regulator; the dosage of the composite oxidant is 0.5-1.5% g / m of the wastewater volume. 3 .

3. A sewage treatment process for organic wastewater according to claim 2, characterized in that: The organophosphonic acid metal complex includes a Cu-ATMP complex, and the Aspergillus niger immobilized microspheres are obtained by the following preparation method: A1. Aspergillus niger in the presence of ATMP and Cu 2+ Cultured in a culture medium for 72 hours to obtain mycelium; B1, mixing mycelium with sodium alginate and Fe3O4 nanoparticles, and dropping them into CaCl2 solution to form magnetic gel microspheres; C1. Surface modification of magnetic gel microspheres was performed using polyethyleneimine to obtain Aspergillus niger immobilized microspheres.

4. The sewage treatment process for organic wastewater according to claim 2, characterized in that: The modified Zn-Mg-Al LDH is prepared by the following method: A2. Using zinc nitrate, magnesium nitrate, and aluminum nitrate as metal sources, a Zn-Mg-AlLDH precursor was synthesized by coprecipitation reaction under alkaline conditions; CQDs dispersion, sodium persulfate, and LDH precursor were mixed; B2. Reaction under alkaline hydrothermal conditions to obtain Zn-Mg-Al LDH with interlayer co-intercalated carbon quantum dots and persulfate, wherein the mass ratio of CQDs to sodium persulfate is 1:1-3; C2. A mesoporous SiO2 shell is formed on the surface of Zn-Mg-Al LDH with interlayer co-intercalated carbon quantum dots and persulfate by a sol-gel method to obtain a modified Zn-Mg-Al LDH containing interlayer co-intercalated carbon quantum dots and persulfate.

5. A sewage treatment process for organic wastewater according to claim 4, characterized in that: The mass ratio of Zn, Mg and Al in the modified Zn-Mg-Al LDH is 0.2:3:

1.

6. The sewage treatment process for organic wastewater according to claim 1, characterized in that: The preparation method of the magnetic layered metal hydroxide material in step S3 is: using Zn-Mg-Al LDH to load on a magnetic fluidized bed adsorption tower, the Zn-Mg-Al LDH particle size is 50-100 μm, and the specific surface area is ≥80 m2 / g to obtain a magnetic layered double metal hydroxide material.

7. A sewage treatment process for organic wastewater according to claim 6, characterized in that: The magnetic field gradient is achieved by a permanent magnet array with an inlet of 0.3 T and an outlet of 0.5 T.

8. The sewage treatment process for organic wastewater according to claim 1, characterized in that: The layered immobilized algae-bacteria symbiotic system in step S5 includes a photobioreactor structure, wherein the upper layer of the photobioreactor structure includes an immobilized Chlorella biofilm, and the immobilized Chlorella biofilm is embedded in a sodium alginate-activated carbon carrier; and the lower layer of the photobioreactor structure includes an aerobic bacterial biofilm, and the bacterial community includes nitrifying bacteria and polyphosphate bacteria.

9. The sewage treatment process for organic wastewater according to claim 1, characterized in that: In step S6, the terminal magnetic recovery uses Fe3O4@diatomaceous earth to separate and recover the magnetic materials in the terminal wastewater.

10. The sewage treatment process for organic wastewater according to claim 1, characterized in that: In step S6, a 254 nm ultraviolet disinfection system is used to disinfect the wastewater.

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