A sewage treatment process for organic wastewater

Abstract

The application discloses a sewage treatment process for organic wastewater, and belongs to the field of sewage treatment, and comprises the following steps: S1, pumping wastewater containing nitrogen-containing organophosphonic acid metal complex into a dielectric barrier discharge reactor, and reducing P-C bond energy through high-energy electron bombardment; S2, adding a modified layered metal hydroxide containing intercalated carbon quantum dots and persulfate and black aspergillus immobilized microspheres into the wastewater treated by plasma; S3, using a magnetic layered metal hydroxide material to deeply adsorb heavy metal ions in the wastewater treated by the composite oxidation under a gradient magnetic field; S4, sequentially passing the wastewater after magnetic adsorption through an anaerobic ammonia oxidation coupling reactor and an aerobic biofilm-activated sludge system to degrade pollutants; S5, using a layered immobilized algal-bacterial symbiotic system to remove phosphorus from the wastewater treated by the biological treatment; and S6, terminal magnetic recovery and water disinfection. The application solves the problems of low and incomplete decomplexing efficiency of the prior art.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment and relates to a wastewater treatment process for organic wastewater. Background Technology

[0002] Complexed heavy metals are relatively difficult to treat in wastewater. Due to the complex forms of pollutants in complexed heavy metal wastewater, the current main treatment technology is to first break the complex and then use conventional methods for treatment. Therefore, it is necessary to use multiple methods and processes in combination for comprehensive treatment of wastewater. For example, oxidation-reduction or electrochemical methods can be used for pretreatment to break the complex, and then chemical precipitation or membrane separation can be used to further reduce the content of heavy metals. These processes are commonly used in practice.

[0003] However, the high PC bond energy in organic phosphonic acid metal complexes makes it difficult for conventional oxidation methods (such as Fenton oxidation and ozone oxidation) to effectively break the complexes in organic wastewater containing nitrogen-containing organophosphonic acid metal complexes, resulting in incomplete decomposition. Furthermore, existing methods such as subsequent chemical precipitation and membrane separation 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 this invention is to provide a wastewater treatment process for organic wastewater, which solves the problem of the current lack of efficient treatment processes for organic wastewater containing nitrogen-containing organophosphonic acid metal complexes.

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

[0006] A wastewater treatment process for organic wastewater includes the following steps:

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

[0008] S2. Composite oxidation treatment: Add a composite oxidant containing modified layered metal hydroxides with intercalated carbon quantum dots and persulfate, and immobilized Aspergillus niger microspheres to the wastewater after plasma treatment, and carry out oxidation and decomposition under controlled alkaline conditions.

[0009] S3. Magnetic adsorption: Utilizing 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 is passed sequentially through an anaerobic ammonia oxidation coupled reactor and an aerobic biofilm-activated sludge system to degrade pollutants.

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

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

[0013] To address the problems of low and incomplete decomplexing efficiency in existing methods, this invention first involves plasma pretreatment of the wastewater before oxidative decomplexing. Dielectric barrier discharge generates high-energy electrons that bombard organophosphonic acid molecules in the wastewater, reducing the PC bond energy to 180-190 kJ / mol and simultaneously increasing the oxidation-reduction potential (ORP) to 150-200 mV. This creates active groups (·OH, SO4·) for subsequent oxidation. - The formation conditions of PC are such that, in the existing technology, the bond energy of PC is high, requiring a very high amount of oxidation, and the decomposition is incomplete;

[0014] Secondly, this application employs a composite oxidant to achieve decomposition. Using a modified layered metal hydroxide containing intercalated carbon quantum dots and persulfate as the core material, this application provides an interlayer reaction site, replacing existing liquid-phase reactions. The interlayer reaction has the effect of interlayer confined oxidation; the modified layered metal hydroxide channels force nitrogen-containing organophosphonic acid metal complexes into close contact and frequent collisions with persulfate, resulting in a concentration enrichment of persulfate in the interlayer, several times higher than the concentration dispersed in solution. Furthermore, the interlayer structure can separate some impurities, reducing interference with the oxidation reaction and achieving decomposition of organophosphonic acid metal complexes. This application utilizes layered metal hydroxides as components for interlayer reactions. Besides their layered structure, these compounds can also trap heavy metal ions and phosphates after decomposition. The decomposition principle in this application is as follows: under alkaline conditions, persulfate is activated to generate sulfate radicals, which preferentially attack weakened PC bonds, achieving decomposition. Carbon quantum dots possess free radical trapping properties, and the adsorption of π electron clouds creates a high concentration region of sulfate radicals on their surface, enriching sulfate radicals in the interlayer and increasing the collision frequency between free radicals and PC bonds, thus contributing to efficient decomposition. This invention lowers the pH of the oxidation environment by reducing bond energy and utilizing interlayer reactions, eliminating the need for a strongly alkaline environment; a near-neutral, weakly alkaline environment is sufficient for oxidative decomposition.

[0015] However, due to the intercalation modification of layered metal hydroxides, the interlayer spacing is increased. During the dynamic reaction of decomposition, some free heavy metal ions 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 complexed again by residual organophosphonic acids in the wastewater, forming stable complexes that are difficult to remove. Therefore, in order to reduce the concentration of free heavy metals in the wastewater, this application incorporates Aspergillus niger immobilized microspheres. The Aspergillus niger microspheres adsorb free heavy metal ions, such as Cu, in real time. 2+ The microspheres secrete oxalic acid to degrade organophosphonic acid residues and block secondary complexation, thus acting as a "capturer" for free heavy metals in the liquid phase. Aspergillus niger produces oxalic acid in a near-neutral environment. Therefore, in order to avoid the impact of the weakly alkaline environment of oxidation on Aspergillus niger, this 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 weakly alkaline, it has little impact on the local pH at the location of the microspheres, allowing the Aspergillus niger microspheres to maintain a near-neutral environment that can produce oxalic acid. The porous structure of the microspheres also facilitates the overflow of oxalic acid from the microspheres.

[0016] Further, the composite oxidant in step S2 comprises the following components in parts by weight: 60-65 parts of modified Zn-Mg-Al LDH containing intercalated carbon quantum dots and persulfate, 25-30 parts of Aspergillus niger immobilized microspheres, and a pH adjuster; the dosage of the composite oxidant is 0.5-1.5% g / m³ of the wastewater volume. 3 .

[0017] Based on current practical applications, this invention proposes a specific implementation scheme for layered metal hydroxides.

[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+ Mycelium was obtained by culturing in the culture medium for 72 hours;

[0020] B1. Mix the mycelium with sodium alginate and Fe3O4 nanoparticles, and drop the mixture into a CaCl2 solution to form magnetic gel microspheres;

[0021] C1. Magnetic gel microspheres were surface-modified with polyethyleneimine to obtain Aspergillus niger immobilized microspheres.

[0022] This invention is mainly used for wastewater containing nitrogen-containing organophosphonic acid copper ion complexes, and for Aspergillus niger in the presence of ATMP and Cu. 2+ During the process of culturing in the culture medium for 72 hours to obtain mycelia, the concentration of ATMP was 0.5-1 mM, and Cu...2+ The concentration is 0.5-2 mM.

[0023] Furthermore, the modified Zn-Mg-Al LDH was 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 under alkaline conditions via a co-precipitation reaction; CQDs dispersion, sodium persulfate, and LDH precursor were mixed.

[0025] B2. Under alkaline hydrothermal conditions, Zn-Mg-AlLDH of intercalated carbon quantum dots and persulfate was obtained by reaction, wherein the mass ratio of CQDs to sodium persulfate was 1:1-3.

[0026] C2. A mesoporous SiO2 shell is formed on the surface of Zn-Mg-Al LDH containing intercalated carbon quantum dots and persulfate by means of sol-gel method, so as to obtain modified Zn-Mg-Al LDH containing 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 as follows: Zn-Mg-AlLDH is loaded onto a magnetic fluidized bed adsorption tower, the particle size of Zn-Mg-Al LDH is 50-100μm, and the specific surface area is ≥80m2 / g, to obtain a magnetic layered bimetallic hydroxide material.

[0029] A gradient magnetic field is applied in the adsorption tower. The magnetic force causes the magnetic components (Fe□O□ or carrier) in the bed to align in an orientation, which drives the loaded LDH particles to be uniformly suspended (fluidized) in the wastewater, increasing the contact area with heavy metal ions.

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

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

[0032] Furthermore, in step S6, the end-of-pipe magnetic recovery uses Fe3O4@diatomaceous earth to separate and recover magnetic materials from the end-of-pipe wastewater.

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

[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 solves the core problems of difficult-to-dissolve and easy-to-re-complex organophosphonic acid complexes by plasma pretreatment, interlayer confined oxidation, and biological synergy. At the same time, by combining magnetic separation and algae-bacterial symbiosis, it also achieves deep removal of heavy metals, phosphorus, and nitrogen, meeting the discharge requirements of wastewater containing nitrogen-containing organophosphonic acid metal complexes.

[0036] 2. This invention utilizes plasma pretreatment and interlayer confined oxidation to lower the pH of the complex. At this pH, combined with the role of microspheres, the microspheres are modified with positive charge by polyethyleneimine, and the surface of the microspheres can effectively adsorb oxalic acid anions, so that the pH of the microspheres is low, which meets the pH requirements for oxalic acid production by Aspergillus niger.

[0037] 3. In this invention, magnetic LDH combined with a gradient magnetic field can achieve deep removal of heavy metal ions, with a removal rate far exceeding that of traditional adsorption materials (such as activated carbon). Attached Figure Description

[0038] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort, wherein:

[0039] Figure 1 This is a process flow diagram for wastewater treatment of organic wastewater;

[0040] Figure 2 This is a TEM image of Aspergillus niger immobilized microspheres. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be 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 for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, and not all embodiments. The components of the embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

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

[0043] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

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

[0045] Example 1

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

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

[0048] S2. Composite oxidation treatment: Add a composite oxidant containing modified layered metal hydroxides with intercalated carbon quantum dots and persulfate, and immobilized Aspergillus niger microspheres to the plasma-treated wastewater, and control the alkaline conditions for oxidation and decomposition, with a pH of 8-8.5.

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

[0050] S4. Biological treatment: The wastewater after magnetic adsorption is passed sequentially through an anaerobic ammonia oxidation coupled reactor and an aerobic biofilm-activated sludge system to degrade pollutants.

[0051] S5. Algae-bacterial symbiotic treatment: A layered immobilized algae-bacterial 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 intercalated carbon quantum dots and persulfate, 25 parts of Aspergillus niger immobilized microspheres, and a pH adjuster; the dosage of the composite oxidant is 1.5% g / m³ of the wastewater volume. 3 .

[0054] The organophosphonic acid metal complexes in the wastewater containing nitrogen-containing organophosphonic acid metal complexes mainly include Cu-ATMP complexes. 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+ Mycelium was obtained by culturing in the culture medium for 72 hours;

[0056] B1. The mycelium was mixed with sodium alginate solution and Fe3O4 nanoparticles to form a suspension, which was then dropped into CaCl2 solution to form magnetic gel microspheres.

[0057] C1. Magnetic gel microspheres were surface-modified with polyethyleneimine to obtain Aspergillus niger immobilized microspheres.

[0058] The dosage standards for mycelium, sodium alginate, and Fe3O4 were as follows: 10g of mycelium, 50ml of sodium alginate solution (4% w / v concentration) per 100mL of suspension, and 2% w / v of Fe3O4 relative to the sodium alginate solution. TEM images of the Aspergillus niger immobilized microspheres are shown below. Figure 2 As shown.

[0059] The modified Zn-Mg-Al LDH was 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 under alkaline conditions via a co-precipitation reaction; CQDs dispersion, sodium persulfate, and LDH precursor were mixed.

[0061] B2. Under alkaline hydrothermal conditions, Zn-Mg-AlLDH of intercalated carbon quantum dots and persulfate was obtained by reaction, wherein the mass ratio of CQDs to sodium persulfate was 1:1-3.

[0062] C2. A mesoporous SiO2 shell is formed on the surface of Zn-Mg-Al LDH containing intercalated carbon quantum dots and persulfate by means of sol-gel method, so as to obtain modified Zn-Mg-Al LDH containing 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 as follows: Zn-Mg-Al LDH is loaded onto a magnetic fluidized bed adsorption tower. The particle size of Zn-Mg-Al LDH is 50-100μm and the specific surface area is ≥80m2 / g, thereby obtaining a magnetic layered bimetallic hydroxide material.

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

[0066] 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, which is embedded in a sodium alginate-activated carbon carrier. The lower layer of the photobioreactor structure includes an aerobic bacterial biofilm, which includes nitrifying bacteria and polyphosphate-accumulating bacteria.

[0067] In step S6, the end-of-pipe magnetic recovery uses Fe3O4@diatomaceous earth to separate and recover magnetic materials from the end-of-pipe wastewater.

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

[0069] Example 2

[0070] Based on Example 1, the composite oxidant in step S2 of this embodiment comprises the following components in parts by weight: 63 parts of modified Zn-Mg-Al LDH containing intercalated carbon quantum dots and persulfate, 28 parts of Aspergillus niger immobilized microspheres, and a pH adjuster; the dosage of the composite oxidant is 0.8% g / m³ of the wastewater volume. 3 .

[0071] Example 3

[0072] Based on Example 1, the composite oxidant in step S2 of this embodiment comprises the following components in parts by weight: 65 parts of modified Zn-Mg-Al LDH containing intercalated carbon quantum dots and persulfate, 30 parts of Aspergillus niger immobilized microspheres, and a pH adjuster; 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, the difference between this comparative example and Example 2 is that this comparative example does not perform plasma pretreatment in step S1, but directly starts water treatment from step S2.

[0075] Comparative Example 2

[0076] Based on Example 2, the difference between this comparative example and Example 2 is that the composite oxidant in 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, without using modified Zn-Mg-Al LDH, and the oxidation and decomposition are carried out under alkaline conditions, with the pH needing to be greater than 10.

[0079] Comparative Example 4

[0080] Based on Example 2, the difference between this comparative example and Example 2 is that the modified Zn-Mg-Al LDH in the composite oxidant of this comparative example only has persulfate intercalation modification and does not add carbon quantum dots.

[0081] Comparative Example 5

[0082] Based on Example 2, the difference between this comparative example and Example 2 is 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 differs from Example 2 in that it does not perform step S3, magnetic adsorption.

[0085] Comparative Example 7

[0086] Based on Example 2, this comparative example differs from Example 2 in that it does not perform S4 or biological treatment.

[0087] Comparative Example 8

[0088] Based on Example 2, this comparative example differs from Example 2 in that it does not perform S5, the algae-bacteria symbiosis treatment.

[0089] Comparative Example 9

[0090] Based on Example 2, this comparative example differs from Example 2 in that it does not perform S6, end-of-pipe magnetic recovery, and effluent disinfection.

[0091] Comparative Example 10

[0092] Based on Example 2, the difference between this comparative example and Example 2 is 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 under alkaline conditions via a co-precipitation reaction; CQDs dispersion, sodium persulfate, and LDH precursor were mixed.

[0094] B2. Under alkaline hydrothermal conditions, Zn-Mg-AlLDH of intercalated carbon quantum dots and persulfate was obtained by reaction, 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 containing intercalated carbon quantum dots and persulfate by means of sol-gel method, so as to obtain modified Zn-Mg-Al LDH containing intercalated carbon quantum dots and persulfate.

[0096] Comparative Example 11

[0097] Based on Example 2, the difference between this comparative example and Example 2 is 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 under alkaline conditions via a co-precipitation reaction; CQDs dispersion, sodium persulfate, and LDH precursor were mixed.

[0099] B2. Under alkaline hydrothermal conditions, Zn-Mg-AlLDH of intercalated carbon quantum dots and persulfate was obtained by reaction, 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 containing intercalated carbon quantum dots and persulfate by means of sol-gel method, so as to obtain modified Zn-Mg-Al LDH containing intercalated carbon quantum dots and persulfate.

[0101] Comparative Example 12

[0102] Based on Example 2, the difference between this comparative example and Example 2 is 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 described in this comparative example is not modified with mesoporous silica and 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 under alkaline conditions via a co-precipitation reaction; CQDs dispersion, sodium persulfate, and LDH precursor were mixed.

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

[0107] Experimental Example 1

[0108] Wastewater containing Cu-ATMP complex (Cu) was collected separately. 2+ 150 mg / L, ATMP 300 mg / L), treated according to the processes of Examples 1-3 and Comparative Examples 1-13, the pH range of decomplexation during the complexation stage and the residual Cu in the treated water were measured. 2+ The concentration and ATMP concentration were used to calculate the removal rate based on the participating concentration and the initial concentration. The above method is the existing technology, and the test results are shown in Table 1.

[0109] Table 1 Pollutant Removal Rate

[0110]

[0111]

[0112] Experimental Example 2

[0113] Based on the water sample from Experiment Example 1, the COD, TN, TP and total bacterial count of the effluent from Examples 1-3 and Comparative Examples 1-13 were determined using existing technologies. The results are shown in Table 2.

[0114] Table 2 Comprehensive Indicators of Effluent

[0115]

[0116]

[0117] Comparing the data in Tables 1 and 2, the wastewater treatment process of this invention demonstrates superior performance in terms of decomposition efficiency, pollutant removal rate, and effluent quality. This invention addresses the challenges of difficult decomposition and easy recomposition of organophosphonic acid complexes through plasma pretreatment, interlayer confined oxidation, and biological synergy, while simultaneously achieving deep removal of heavy metals, nitrogen, and phosphorus. The effluent indicators are comprehensively superior to those of traditional processes. Example 2 represents the optimal solution. In addition to pollutants such as nitrogen and organophosphonic acid metal complexes, organic wastewater generally contains other organic pollutants; therefore, this invention employs a multi-step synergistic treatment approach.

[0118] The above description is merely 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 those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A sewage treatment process for organic wastewater, characterized by: The method comprises the following steps: S1, plasma pretreatment: pumping the wastewater containing the metal complex of phosphonic acid containing nitrogen into a dielectric barrier discharge reactor, reducing the P-C bond energy to 180-190 kJ / mol by high-energy electron bombardment, and controlling the effluent ORP at 150-200 mV; S2, composite oxidation treatment: adding a composite oxidant comprising a modified layered metal hydroxide containing intercalated carbon quantum dots and persulfate, and Aspergillus niger immobilized microspheres to the wastewater after plasma treatment, and controlling the alkaline condition for oxidative decomplexation; S3, magnetic adsorption: using the magnetic layered metal hydroxide material to deeply adsorb heavy metal ions in the wastewater after composite oxidation treatment under a gradient magnetic field; S4, biological treatment: the wastewater after magnetic adsorption is sequentially degraded through an anaerobic ammonia oxidation coupling reactor and an aerobic biofilm-activated sludge system; S5, algal-bacterial symbiotic treatment: using a layered immobilized algal-bacterial symbiotic system to remove phosphorus from the wastewater after biological treatment; S6, terminal magnetic recovery and effluent disinfection.

2. A sewage treatment process for organic waste water as claimed in claim 1 wherein: The composite oxidant in the step S2 comprises the following components 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, a pH regulator; the dosage of the composite oxidant is 0.5-1.5% g / m 3 .

3. A sewage treatment process for organic waste water as claimed in claim 2 wherein: The metal complex of phosphonic acid contains Cu-ATMP complex, and the Aspergillus niger immobilized microspheres are prepared by the following method: A1. Aspergillus niger in the presence of ATMP and Cu 2+ Mycelium was obtained by culturing in the culture medium for 72 hours; B1, mixing the mycelium with sodium alginate and Fe3O4 nanoparticles, and dropping into a CaCl2 solution to form magnetic gel microspheres; C1, surface modification of the magnetic gel microspheres with polyethyleneimine to obtain Aspergillus niger immobilized microspheres.

4. The wastewater 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, synthesizing a Zn-Mg-Al LDH precursor by a coprecipitation reaction under alkaline conditions; mixing a CQDs dispersion, sodium persulfate and the LDH precursor; B2, obtaining a Zn-Mg-Al LDH containing intercalated carbon quantum dots and persulfate under alkaline hydrothermal conditions, wherein the mass ratio of CQDs to sodium persulfate is 1:1-3; C2, forming a mesoporous SiO2 shell on the surface of the Zn-Mg-Al LDH containing intercalated carbon quantum dots and persulfate by a sol-gel method to obtain a modified Zn-Mg-Al LDH containing intercalated carbon quantum dots and persulfate.

5. A sewage treatment process for organic waste water as claimed in claim 4 wherein: The mass ratio of Zn, Mg and Al in the modified Zn-Mg-Al LDH is 0.2:3:

1.

6. A sewage treatment process for organic waste water as claimed in claim 1 wherein: The preparation method of the magnetic layered metal hydroxide material in step S3 is as follows: loading the Zn-Mg-Al LDH in a magnetic fluidized bed adsorption tower, and the particle size of the Zn-Mg-Al LDH 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 waste water as claimed in claim 6 wherein: The magnetic field gradient is realized by a permanent magnet array with an inlet of 0.3 T and an outlet of 0.5 T.

8. A sewage treatment process for organic waste water as claimed in claim 1, wherein: The layered immobilized algal-bacterial symbiotic system in the step S5 comprises a photobioreactor structure, an upper layer of the photobioreactor structure comprises an immobilized chlorella biofilm embedded in a sodium alginate-activated carbon carrier, and a lower layer of the photobioreactor structure comprises an aerobic bacterial community biofilm, the bacterial community comprising nitrifying bacteria and phosphorus accumulating bacteria.

9. A sewage treatment process for organic waste water as claimed in claim 1 wherein: In the step S6, the terminal magnetic recovery is performed by using Fe3O4@diatomite to separate and recover the magnetic material in the terminal wastewater.

10. A sewage treatment process for organic waste water as claimed in claim 1 wherein: In the effluent disinfection in the step S6, a 254 nm ultraviolet disinfection system is used for wastewater disinfection.

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