Energy-saving and recycling method and system for treating erythromycin thiocyanate wastewater

Abstract

The application discloses an energy-saving and recycling erythromycin thiocyanate wastewater treatment method and system, which comprises the following steps: firstly pretreating high-concentration erythromycin thiocyanate wastewater; adding an oxidizing agent to effluent water after the first pretreatment and evaporating and concentrating; carrying out anaerobic ammonia oxidation treatment on condensate generated in the evaporation and concentration; mixing mother liquor generated in the evaporation and concentration with low-concentration erythromycin thiocyanate wastewater and secondarily pretreating the mixed wastewater; mixing effluent water after the secondary pretreatment with effluent water after the anaerobic ammonia oxidation treatment and carrying out hydrolytic acidification treatment on the mixed effluent water; sequentially carrying out anaerobic treatment, advanced biochemical treatment and advanced catalytic oxidation treatment on effluent water after the hydrolytic acidification treatment, and discharging the effluent water up to the standard. The application combines the oxidation process with the evaporation process, simultaneously and efficiently removes erythromycin titer and thiocyanate, and eliminates the inhibition of the anaerobic biological process.

Description

Technical Field

[0001] This invention relates to the field of antibiotic production wastewater treatment technology, specifically to an energy-saving and recyclable erythromycin thiocyanate wastewater treatment method and system. Background Technology

[0002] Erythromycin thiocyanate wastewater presents industry challenges such as high organic matter concentration, poor biodegradability, and high biological toxicity. Typically, this type of wastewater has a COD concentration of 10,000-100,000 mg / L, an NH4-N concentration of 500-1,000 mg / L, and a thiocyanate concentration of 1,000-2,000 mg / L. It is a typical high-concentration, recalcitrant organic wastewater with significant environmental hazards and treatment difficulties.

[0003] Currently, biochemical processes are commonly used to treat thiocyanate wastewater, but these methods suffer from operational instability and difficulty in consistently meeting effluent quality standards. The reason for this is that the high concentrations of erythromycin residue and thiocyanate in erythromycin wastewater strongly inhibit and toxicize microbial activity, limiting the effectiveness of biological treatment and resulting in substandard effluent quality. Furthermore, the presence of high-concentration erythromycin residue easily leads to the generation of large numbers of drug-resistant bacteria and genes during biological treatment. These substances, along with undegraded antibiotics, may enter the environment with the treated wastewater and residual sludge, posing a significant ecological safety hazard. Therefore, achieving efficient and selective pre-treatment of thiocyanate in wastewater is a crucial step in realizing efficient and low-cost biological treatment of this type of wastewater. Summary of the Invention

[0004] To address the shortcomings of existing erythromycin thiocyanate wastewater treatment processes, such as poor thiocyanate removal, strong microbial inhibition, unstable system operation, high energy consumption, and difficulty in consistently meeting effluent standards, this invention provides an energy-saving and recyclable erythromycin thiocyanate wastewater treatment method and system. This system efficiently removes pollutants, ensures stable effluent compliance, and achieves energy recycling, significantly reducing process operating energy consumption and costs.

[0005] The first objective of this invention is to provide an energy-saving and recyclable method for treating erythromycin thiocyanate wastewater, comprising: Step 1: Perform a primary pretreatment on the high-concentration erythromycin cyanate wastewater; wherein, the primary pretreatment includes adjusting the pH and adding coagulant and flocculant; Step 2: Add oxidant to the effluent after the first pretreatment and then evaporate and concentrate it; Step 3: Perform anaerobic ammonia oxidation treatment on the condensate produced by evaporation and concentration; Step 4: Mix the mother liquor produced by evaporation and concentration with low-concentration erythromycin thiocyanate wastewater, and perform secondary pretreatment on the mixed waste liquid; wherein, the secondary pretreatment includes adding oxidant, adding reducing agent, adding coagulant and flocculant; Step 5: Mix the effluent after secondary pretreatment with the effluent after anaerobic ammonia oxidation treatment, and then perform hydrolysis acidification treatment on the mixed effluent. Step 6: Anaerobic treatment of the effluent after hydrolysis and acidification; Step 7: Perform advanced biological treatment on the effluent after anaerobic treatment; Step 8: Perform advanced catalytic oxidation treatment on the effluent after deep biological treatment, and discharge the effluent that meets the standards after advanced catalytic oxidation treatment.

[0006] Furthermore, the COD concentration of the high-concentration erythromycin cyanate wastewater is 10,000-100,000 mg / L, and the thiocyanate concentration is 100-2,000 mg / L; the COD concentration of the low-concentration erythromycin cyanate wastewater is 100-10,000 mg / L, and the thiocyanate concentration is <100 mg / L.

[0007] Further, step 1 specifically includes: The pH of the high-concentration erythromycin thiocyanate wastewater was adjusted to 6-7.5. Coagulants and flocculants were added to the high-concentration erythromycin thiocyanate wastewater after pH adjustment to facilitate precipitation, thereby partially removing organic matter, hardness, and suspended solids from the wastewater and reducing the treatment load of subsequent evaporation treatment.

[0008] Further, step 2 specifically includes: An oxidant is added to the effluent after the first pretreatment to carry out an oxidation reaction, and then it enters the evaporation unit for further oxidation treatment and evaporation concentration. The high temperature of evaporation further improves the removal efficiency of the oxidant, removes the high concentration of thiocyanate in the high-concentration erythromycin thiocyanate wastewater, and reduces the toxicity to subsequent biochemical system treatment. The oxidant includes one or more of hydrogen peroxide, sodium perchlorate, sodium chlorate, sodium hypochlorite and potassium permanganate. The mass ratio of the oxidant to thiocyanate is (2~10):1, and the operating temperature of the evaporation unit is 80~110℃.

[0009] Furthermore, step 3 specifically includes: The condensate produced by evaporation and concentration enters the anaerobic ammonia oxidation unit, where the pH is adjusted to 7-9.5 and nutrients are added. Ammonia-oxidizing bacteria are used to remove a small amount of organic matter and most of the high-concentration ammonia nitrogen contained in the evaporation condensate.

[0010] Furthermore, step 4 specifically includes: The mother liquor produced by evaporation and concentration is mixed with low-concentration erythromycin thiocyanate wastewater, and an oxidant is added to the mixed wastewater for secondary oxidation to further reduce the bioinhibitory effect of thiocyanate in the mixed solution; wherein, the oxidant includes one or more of hydrogen peroxide, sodium perchlorate, sodium chlorate, sodium hypochlorite and potassium permanganate, the mass ratio of the oxidant to thiocyanate is (2~10):1, and the oxidation reaction time of the secondary oxidation is 1~4h; After secondary oxidation, a reducing agent is added to reduce the residual oxidant; wherein the reducing agent includes one or more of sodium sulfite, sodium bisulfite and ferrous sulfate, and the effluent ORP after adding the reducing agent is <50mv; After reduction, continue to add coagulants and flocculants to allow for sedimentation.

[0011] Furthermore, in step 6, the organic matter in the influent is converted into biogas after anaerobic treatment, and then enters the biogas boiler after biogas treatment to generate steam for supplementing the steam of the evaporation unit.

[0012] Furthermore, it also includes: The sludge generated during primary pretreatment, anaerobic ammonia oxidation, secondary pretreatment, hydrolysis acidification, anaerobic treatment, deep biological treatment, and advanced catalytic oxidation is dewatered and then transported off-site for disposal.

[0013] The second objective of this invention is to provide an energy-saving and recyclable erythromycin thiocyanate wastewater treatment system for implementing the above-mentioned treatment method, comprising: a primary pretreatment unit, an evaporation unit, an anaerobic ammonia oxidation unit, a secondary pretreatment unit, an equalization tank, a hydrolysis acidification unit, an anaerobic unit, a deep biochemical treatment unit, and an advanced catalytic oxidation treatment unit. High-concentration erythromycin thiocyanate wastewater flows into the primary pretreatment unit, while low-concentration erythromycin thiocyanate wastewater flows into the secondary pretreatment unit. The primary pretreatment unit, evaporation unit, and anaerobic ammonia oxidation unit are connected sequentially. The secondary pretreatment unit, equalization tank, hydrolysis acidification unit, anaerobic unit, deep biological treatment unit, and advanced catalytic oxidation treatment unit are connected sequentially. The effluent from the advanced catalytic oxidation treatment unit meets discharge standards. The evaporation unit is connected to the secondary pretreatment unit, so that the condensate produced after evaporation and concentration enters the anaerobic ammonia oxidation unit, and the mother liquor produced after evaporation and concentration enters the secondary pretreatment unit; the anaerobic ammonia oxidation unit is connected to the equalization tank; The primary pretreatment unit is connected to a first pH adjustment dosing unit and a first coagulation and flocculation dosing unit. The effluent pipe between the primary pretreatment unit and the evaporation unit is connected to a first oxidant dosing unit. The anaerobic ammonia oxidation unit is connected to a second pH adjustment dosing unit and a nutrient dosing unit. The secondary pretreatment unit is connected to a second oxidant dosing unit, a reducing agent dosing unit, and a second coagulation and flocculation dosing unit.

[0014] Furthermore, it also includes: a biogas treatment unit, a biogas boiler, and a sludge dewatering unit; The biogas produced by the anaerobic unit passes sequentially through the biogas treatment unit and the biogas boiler. The biogas boiler is connected to the evaporation unit, and the steam generated by burning the biogas in the biogas boiler is used to supply steam to the evaporation unit. The sludge produced by the primary pretreatment unit, anaerobic ammonia oxidation unit, secondary pretreatment unit, hydrolysis acidification unit, anaerobic unit, deep biochemical treatment unit, and advanced catalytic oxidation treatment unit all enter the sludge dewatering unit.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention, building upon the advantages of existing biochemical treatment methods, combines oxidation and evaporation processes to simultaneously and efficiently remove erythromycin potency and thiocyanate ions, while also mitigating their inhibitory effects on anaerobic biological processes. Furthermore, the organic matter in the wastewater is converted into biogas to generate steam, which is then used to supplement the evaporation system. This low-energy, energy-efficient treatment of erythromycin thiocyanate wastewater demonstrates exceptional economic efficiency and stability. The application of this invention can completely overcome the shortcomings of existing erythromycin thiocyanate treatment processes, and it possesses a very broad market application prospect. Attached Figure Description

[0016] Figure 1 This is a process flow diagram of the energy-saving and recyclable erythromycin thiocyanate wastewater treatment system and method disclosed in this invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] The present invention will now be described in further detail with reference to the accompanying drawings: like Figure 1As shown, this invention provides an energy-saving and recyclable erythromycin thiocyanate wastewater treatment system, comprising: a primary pretreatment unit 1, an evaporation unit 2, an anaerobic ammonia oxidation unit 3, a secondary pretreatment unit 4, an equalization tank 5, a hydrolysis acidification unit 6, an anaerobic unit 7, a deep biochemical treatment unit 8, an advanced catalytic oxidation treatment unit 9, a biogas treatment unit 10, a biogas boiler 11, and a sludge dewatering unit 12; wherein, high-concentration erythromycin thiocyanate wastewater flows into the primary pretreatment unit 1, and low-concentration erythromycin thiocyanate wastewater flows into the secondary pretreatment unit 4; the primary pretreatment unit 1, the evaporation unit 2, the anaerobic ammonia oxidation unit 3, the secondary pretreatment unit 4, the equalization tank 5, the hydrolysis acidification unit 6, the anaerobic unit 7, the deep biochemical treatment unit 8, the advanced catalytic oxidation treatment unit 9, the biogas treatment unit 10, the biogas boiler 11, and the ... The evaporation unit 2 and the anaerobic ammonia oxidation unit 3 are connected sequentially. The secondary pretreatment unit 4, the equalization tank 5, the hydrolysis acidification unit 6, the anaerobic unit 7, the deep biological treatment unit 8, and the advanced catalytic oxidation treatment unit 9 are connected sequentially. The effluent from the advanced catalytic oxidation treatment unit 9 meets the discharge standards. The evaporation unit 2 is connected to the secondary pretreatment unit 4, so that the condensate produced after evaporation and concentration enters the anaerobic ammonia oxidation unit 3, and the mother liquor produced after evaporation and concentration enters the secondary pretreatment unit 4. The anaerobic ammonia oxidation unit 3 is connected to the equalization tank 5.

[0019] The primary pretreatment unit 1 is connected to a first pH adjustment dosing unit and a first coagulation and flocculation dosing unit. The effluent pipe between the primary pretreatment unit 1 and the evaporation unit 2 is connected to a first oxidant dosing unit. The anaerobic ammonia oxidation unit 3 is connected to a second pH adjustment dosing unit and a nutrient dosing unit. The secondary pretreatment unit 4 is connected to a second oxidant dosing unit, a reducing agent dosing unit, and a second coagulation and flocculation dosing unit.

[0020] The biogas produced by the anaerobic unit 7 passes sequentially through the biogas treatment unit 10 and the biogas boiler 11. The biogas boiler 11 is connected to the evaporation unit 2, and the steam generated by burning the biogas in the biogas boiler 11 is used to supply steam to the evaporation unit 2. The sludge produced by the primary pretreatment unit 1, the anaerobic ammonia oxidation unit 3, the secondary pretreatment unit 4, the hydrolysis acidification unit 6, the anaerobic unit 7, the deep biochemical treatment unit 8, and the advanced catalytic oxidation treatment unit 9 all enter the sludge dewatering unit 12.

[0021] This invention provides an energy-saving and recyclable method for treating erythromycin thiocyanate wastewater, comprising: Step 1: The high-concentration erythromycin thiocyanate wastewater enters the primary pretreatment unit 1 for pH adjustment, adjusting its pH value to 6-7.5; coagulant and flocculant are added to the pH-adjusted high-concentration erythromycin thiocyanate wastewater for precipitation, in order to partially remove organic matter, hardness and suspended solids in the high-concentration wastewater, and reduce the treatment load of subsequent evaporation treatment.

[0022] Step 2: An oxidant is added to the effluent after the first pretreatment to carry out an oxidation reaction. Then, it enters the evaporation unit 2 for further oxidation treatment and evaporation concentration. The high temperature of evaporation further improves the removal efficiency of the oxidant, removes the high concentration of thiocyanate in the high-concentration erythromycin thiocyanate wastewater, and reduces the toxicity to the subsequent biochemical system treatment. The oxidant includes one or more of hydrogen peroxide, sodium perchlorate, sodium chlorate, sodium hypochlorite, and potassium permanganate. The mass ratio of the oxidant to thiocyanate is (2~10):1. The operating temperature of the evaporation unit is 80~110℃. The evaporation unit 2 can adopt a single or multiple evaporation systems such as MVR or multi-effect evaporation.

[0023] Step 3: The condensate produced by evaporation and concentration enters the anaerobic ammonia oxidation unit 3, where the pH value is adjusted to 7-9.5 and nutrients are added. Ammonia oxidizing bacteria are used to remove a small amount of organic matter and most of the high-concentration ammonia nitrogen and total nitrogen contained in the evaporation condensate, converting the ammonia nitrogen into nitrogen gas for emission.

[0024] Step 4: The mother liquor produced by evaporation and concentration is mixed with the low-concentration erythromycin thiocyanate wastewater in the secondary pretreatment unit 4. An oxidant is added to the mixed wastewater for secondary oxidation to further reduce the concentration and biotoxicity of thiocyanate in the mixed liquid. The oxidant includes one or more of hydrogen peroxide, sodium perchlorate, sodium chlorate, sodium hypochlorite, and potassium permanganate. The mass ratio of the oxidant to thiocyanate is (2~10):1, and the oxidation reaction time for the secondary oxidation is 1~4 hours. After the secondary oxidation, a reducing agent is added to reduce the residual oxidant and avoid oxidant residue. The reducing agent includes one or more of sodium sulfite, sodium bisulfite, and ferrous sulfate. The effluent ORP after adding the reducing agent is <50mv. After reduction, coagulant and flocculant are added for precipitation. Through the above operations, thiocyanate can be removed, biotoxicity can be reduced, and sludge-water separation can be achieved through one or more processes such as sedimentation tank, sludge dewatering machine, or membrane filtration to remove SS and some organic matter, thereby reducing the load on subsequent treatment.

[0025] Step 5: The effluent after secondary pretreatment and the effluent after anaerobic ammonia oxidation treatment are mixed in the equalization tank 5. The mixed effluent enters the hydrolysis acidification unit 6 for hydrolysis acidification treatment to further improve biodegradability. The hydrolysis acidification removes residual nitrate nitrogen in the effluent after anaerobic ammonia oxidation treatment, further improving the total nitrogen removal rate, improving biodegradability, and providing some ammonia nitrogen for anaerobic treatment, thereby improving the stability of the anaerobic system.

[0026] Step 6: The effluent after hydrolysis and acidification treatment enters the anaerobic unit 7. The anaerobic unit 7 converts the organic matter in the influent into biogas, which then enters the biogas boiler 11 after passing through the biogas treatment unit 10. The generated steam is used to supplement the steam of the evaporation unit 2, thereby greatly reducing the overall system energy consumption.

[0027] Step 7: The effluent after anaerobic treatment enters the advanced biological treatment unit 8, where the remaining pollutants such as COD, NH3-N, TN, and TP are further removed through anoxic-aerobic processes.

[0028] Step 8: The effluent after deep biological treatment enters the advanced catalytic oxidation treatment unit 9 to further remove the remaining organic matter that is difficult to biodegrade, thereby achieving the standard discharge.

[0029] Step 9: The sludge generated during the primary pretreatment, anaerobic ammonia oxidation treatment, secondary pretreatment, hydrolysis acidification treatment, anaerobic treatment, deep biological treatment and advanced catalytic oxidation treatment is dewatered and then transported off-site for disposal.

[0030] The COD concentration of the high-concentration erythromycin cyanate wastewater is 10,000-100,000 mg / L, and the thiocyanate concentration is 100-2,000 mg / L. The low-concentration erythromycin cyanate wastewater has a COD concentration of 100-10,000 mg / L and a thiocyanate concentration of <100 mg / L.

[0031] Furthermore, the mother liquor produced by the evaporation unit can also be directly dehydrated, desalinated, and transported off-site for disposal.

[0032] Furthermore, the effluent from the anaerobic ammonia oxidation unit can be directly fed into the advanced biological treatment unit, or it can be mixed with the secondary pretreatment effluent from the low-concentration erythromycin thiocyanate wastewater and then fed into the hydrolysis acidification unit to further remove residual nitrate nitrogen and organic matter in the mixed wastewater, thereby improving biodegradability and denitrification.

[0033] The above are merely preferred embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An energy-saving and recyclable method for treating erythromycin thiocyanate wastewater, characterized in that, include: Step 1: Perform a primary pretreatment on the high-concentration erythromycin thiocyanate wastewater; wherein, the primary pretreatment includes adjusting the pH and adding coagulant and flocculant; Step 2: Add an oxidant to the effluent after the first pretreatment and then evaporate and concentrate it; specifically, this includes: adding an oxidant to the effluent after the first pretreatment to carry out an oxidation reaction, and then entering the evaporation unit for oxidation treatment and evaporation concentration, utilizing the high temperature of evaporation to improve the removal efficiency of the oxidant for thiocyanate, and removing the high concentration of thiocyanate from the high-concentration erythromycin thiocyanate wastewater; wherein, the oxidant includes one or more of hydrogen peroxide, sodium perchlorate, sodium chlorate, sodium hypochlorite and potassium permanganate, the mass ratio of the oxidant to thiocyanate is (2~10):1, and the operating temperature of the evaporation unit is 80~110℃; Step 3: Perform anaerobic ammonia oxidation treatment on the condensate produced by evaporation and concentration; Step 4: Mix the mother liquor produced by evaporation and concentration with low-concentration erythromycin thiocyanate wastewater, and perform secondary pretreatment on the mixed wastewater. The secondary pretreatment includes adding an oxidant, a reducing agent, a coagulant, and a flocculant. Specifically, this includes mixing the mother liquor produced by evaporation and concentration with the low-concentration erythromycin thiocyanate wastewater, and adding an oxidant to the mixed wastewater for secondary oxidation. The oxidant includes one or more of hydrogen peroxide, sodium perchlorate, sodium chlorate, sodium hypochlorite, and potassium permanganate, with a mass ratio of oxidant to thiocyanate of (2~10):

1. The oxidation reaction time for the secondary oxidation is 1~4 hours. After the secondary oxidation, a reducing agent is added to reduce the remaining oxidant. The reducing agent includes one or more of sodium sulfite, sodium bisulfite, and ferrous sulfate. The effluent ORP after adding the reducing agent is <50 mV. After reduction, coagulants and flocculants are added for precipitation. Step 5: Mix the effluent after secondary pretreatment with the effluent after anaerobic ammonia oxidation treatment, and then perform hydrolysis acidification treatment on the mixed effluent. Step 6: Anaerobic treatment of the effluent after hydrolysis and acidification; Step 7: Perform advanced biological treatment on the effluent after anaerobic treatment; Step 8: Perform advanced catalytic oxidation treatment on the effluent after deep biological treatment, and discharge the effluent that meets the standards after advanced catalytic oxidation treatment; The high-concentration erythromycin thiocyanate wastewater has a COD concentration of 10,000-100,000 mg / L and a thiocyanate concentration of 100-2,000 mg / L, while the low-concentration erythromycin thiocyanate wastewater has a COD concentration of 100-10,000 mg / L and a thiocyanate concentration of <100 mg / L.

2. The processing method as described in claim 1, characterized in that, Step 1 specifically includes: The pH of the high-concentration erythromycin thiocyanate wastewater was adjusted to 6-7.

5. Coagulants and flocculants were added to the high-concentration erythromycin thiocyanate wastewater after pH adjustment to induce precipitation, thereby partially removing organic matter, hardness, and suspended solids from the high-concentration wastewater.

3. The processing method as described in claim 1, characterized in that, Step 3 specifically includes: The condensate produced by evaporation and concentration enters the anaerobic ammonia oxidation unit, where the pH is adjusted to 7-9.5 and nutrients are added. Anaerobic ammonia oxidizing bacteria are used to remove a small amount of organic matter and most of the high-concentration ammonia nitrogen contained in the evaporation condensate.

4. The processing method as described in claim 1, characterized in that, In step 6, the organic matter in the influent is converted into biogas after anaerobic treatment. After biogas treatment, it enters the biogas boiler to generate steam for supplementing the steam of the evaporation unit.

5. The processing method as described in claim 1, characterized in that, Also includes: The sludge generated during primary pretreatment, anaerobic ammonia oxidation, secondary pretreatment, hydrolysis acidification, anaerobic treatment, deep biological treatment, and advanced catalytic oxidation is dewatered and then transported off-site for disposal.

6. An energy-saving and recyclable erythromycin thiocyanate wastewater treatment system, used to implement the treatment method as described in any one of claims 1 to 3, characterized in that, include: The system includes a primary pretreatment unit, an evaporation unit, an anaerobic ammonia oxidation unit, a secondary pretreatment unit, an equalization tank, a hydrolysis acidification unit, an anaerobic unit, a deep biological treatment unit, and an advanced catalytic oxidation treatment unit. High-concentration erythromycin thiocyanate wastewater flows into the primary pretreatment unit, while low-concentration erythromycin thiocyanate wastewater flows into the secondary pretreatment unit. The primary pretreatment unit, evaporation unit, and anaerobic ammonia oxidation unit are connected sequentially. The secondary pretreatment unit, equalization tank, hydrolysis acidification unit, anaerobic unit, deep biological treatment unit, and advanced catalytic oxidation treatment unit are connected sequentially. The effluent from the advanced catalytic oxidation treatment unit meets discharge standards. The evaporation unit is connected to the secondary pretreatment unit, so that the condensate produced after evaporation and concentration enters the anaerobic ammonia oxidation unit, and the mother liquor produced after evaporation and concentration enters the secondary pretreatment unit; the anaerobic ammonia oxidation unit is connected to the equalization tank; The primary pretreatment unit is connected to a first pH adjustment dosing unit and a first coagulation and flocculation dosing unit. The effluent pipe between the primary pretreatment unit and the evaporation unit is connected to a first oxidant dosing unit. The anaerobic ammonia oxidation unit is connected to a second pH adjustment dosing unit and a nutrient dosing unit. The secondary pretreatment unit is connected to a second oxidant dosing unit, a reducing agent dosing unit, and a second coagulation and flocculation dosing unit.

7. The processing system as described in claim 6, characterized in that, Also includes: Biogas treatment unit, biogas boiler and sludge dewatering unit; The biogas produced by the anaerobic unit passes sequentially through the biogas treatment unit and the biogas boiler. The biogas boiler is connected to the evaporation unit, and the steam generated by burning the biogas in the biogas boiler is used to supply steam to the evaporation unit. The sludge produced by the primary pretreatment unit, anaerobic ammonia oxidation unit, secondary pretreatment unit, hydrolysis acidification unit, anaerobic unit, deep biochemical treatment unit, and advanced catalytic oxidation treatment unit all enter the sludge dewatering unit.

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