An aerobic granular sludge sewage treatment process

Abstract

This invention relates to the field of environmental engineering technology, specifically to an aerobic granular sludge wastewater treatment process, comprising the following steps: S1: ultrasonic treatment of raw wastewater; S2: preliminary screening of the ultrasonically treated wastewater; S3: adjusting the pH value of the screened wastewater and adding nutrients; S4: injecting the adjusted wastewater into a biological reaction zone containing pre-cultured aerobic granular sludge and performing intermittent aeration; S5: periodically performing microwave treatment during the biological reaction process; S6: chemical precipitation of the biologically treated wastewater; S7: microfiltration of the biologically and chemically treated wastewater; S8: ozone and ultraviolet light treatment of the microfiltered water; S9: terminal disinfection of the treated water. This invention effectively promotes the formation and stabilization of aerobic granular sludge, improves the removal efficiency of pollutants such as organic matter, nitrogen, and phosphorus in wastewater, and ensures that the effluent quality meets standards.

Description

Technical Field

[0001] This invention relates to the field of environmental engineering technology, and in particular to an aerobic granular sludge wastewater treatment process. Background Technology

[0002] With the development of the social economy and the acceleration of urbanization, wastewater treatment has become one of the important issues in the field of environmental protection. Traditional wastewater treatment processes, such as the activated sludge process, have achieved certain results in treating organic pollutants, nitrogen, and phosphorus in wastewater. However, they still face a series of challenges during operation, such as sludge bulking, large sludge production, and low nitrogen and phosphorus removal efficiency in wastewater. In recent years, aerobic granular sludge technology has gradually become a research hotspot in the field of wastewater treatment due to its advantages such as good sludge settling properties, high treatment efficiency, and small system footprint. This technology forms granular sludge through the natural aggregation of aerobic microorganisms, which can maintain stable operation under high load conditions and has a high sludge recycling rate. However, in practical applications, the formation conditions of aerobic granular sludge are relatively complex. How to stably generate granular sludge and maintain its structure and activity during long-term operation remains one of the difficulties in the large-scale promotion of this technology.

[0003] Existing aerobic granular sludge technology still faces several technical bottlenecks in its application. Firstly, the degradation of large organic molecules in wastewater is difficult, affecting the biological activity and formation process of aerobic granular sludge. Secondly, in high-load wastewater treatment, the balance of nutrients such as nitrogen and phosphorus is not precisely controlled, leading to unsatisfactory nitrogen and phosphorus removal effects. Furthermore, the structural stability of sludge particles is poor, making them susceptible to external conditions such as aeration methods and chemical substances, thus impacting the efficiency and operating costs of the entire treatment system. Therefore, developing an aerobic granular sludge wastewater treatment process that can effectively solve these problems is particularly necessary. Summary of the Invention

[0004] To achieve the above objectives, the present invention provides an aerobic granular sludge wastewater treatment process.

[0005] An aerobic granular sludge wastewater treatment process includes the following steps:

[0006] S1: Ultrasonic treatment of raw wastewater to break down large organic molecules in the wastewater;

[0007] S2: Perform preliminary screening on the ultrasonically treated wastewater to remove large suspended solids and easily deposited matter;

[0008] S3: Adjust the pH value of the wastewater after screening and add nutrients to maintain nutrient balance;

[0009] S4: Inject the adjusted wastewater into the biological reaction zone containing pre-cultured aerobic granular sludge and perform intermittent aeration to promote microbial activity and sludge particle maturation.

[0010] S5: Microwave treatment is performed periodically during the biological reaction process to enhance the structural stability of sludge particles;

[0011] S6: Chemically precipitate the biologically treated wastewater and add a predetermined amount of flocculant to remove dissolved phosphorus;

[0012] S7: Micro-filter the wastewater that has undergone biological and chemical treatment to remove residual sludge particles and fine suspended solids;

[0013] S8: The micro-filtered water is treated with ozone and ultraviolet light to degrade residual recalcitrant organic matter;

[0014] S9: Perform end-of-pipe disinfection on the treated water to ensure it meets discharge standards.

[0015] Optionally, S1 specifically includes:

[0016] S11: Preheat the raw wastewater before it enters the ultrasonic treatment process, adjusting the temperature to 20 to 30 degrees Celsius to optimize the efficiency of the ultrasonic treatment.

[0017] S12: The preheated wastewater is introduced into the ultrasonic reactor, wherein the frequency of the ultrasonic equipment is set between 25kHz and 35kHz, and the power density is controlled between 0.5 and 1.0W / cm³. 2 ;

[0018] S13: The duration of ultrasonic treatment is 5 to 15 minutes to ensure that large molecular organic matter in the wastewater is fully broken down.

[0019] Optionally, S2 specifically includes:

[0020] S21: The ultrasonically treated wastewater is transported to the preliminary screening station, where it is physically intercepted using a rotating screen;

[0021] S22: The mesh size of the screen is set to 0.5 to 1.0 mm to capture and remove large suspended solids and easily deposited matter;

[0022] S23: The flow rate of the screening operation is controlled at 100 to 200 cubic meters per hour;

[0023] S24: The screened wastewater is collected and diverted to the next treatment stage, while the screened solid waste is periodically removed from the screen.

[0024] Optionally, S3 specifically includes:

[0025] S31: Preliminary determination of the pH value of the screened wastewater, specifically using an online pH meter for continuous monitoring;

[0026] S32: If the pH value is below 6.5, sodium hydroxide will be automatically added for adjustment; if the pH value is above 7.5, hydrochloric acid will be added for adjustment, with the target pH value being 6.5 to 7.5.

[0027] S33: Add nutrients, including nitrogen and phosphorus sources, wherein the nitrogen source is selected from urea or ammonium nitrate, and the phosphorus source is selected from potassium dihydrogen phosphate or diammonium phosphate;

[0028] S34: The added nutrients are formulated according to the ratio of chemical oxygen demand (COD). Specifically, the ratio of nitrogen to phosphorus is COD:N = 100:5:1, which means that 5 grams of nitrogen and 1 gram of phosphorus need to be added for every 100 grams of COD.

[0029] Optionally, S4 specifically includes:

[0030] S41: The wastewater with adjusted pH and nutrients is pumped to the biological reaction zone at a fixed flow rate of 1-3 m / s. 3 / h;

[0031] S42: The biological reaction zone is pre-filled with aerobic granular sludge, and the initial concentration of the sludge is controlled at 3000 to 5000 mg / L;

[0032] S43: Oxygen is supplied using an intermittent aeration method, with each aeration cycle consisting of 10 minutes of continuous aeration and 5 minutes of aeration stop;

[0033] S44: During aeration, maintain the dissolved oxygen concentration at 2 to 4 mg / L to maintain suitable biological activity;

[0034] S45: After aeration, allow the sludge particles to settle naturally.

[0035] Optionally, S5 specifically includes:

[0036] S51: A microwave transmitter is installed in the bioreactor; and the frequency of the microwave treatment is set to 2.45 GHz;

[0037] S52: The duration of each microwave treatment is set to 30 to 90 seconds, and microwave treatment is performed every 30 to 60 minutes;

[0038] S53: Before each microwave treatment begins, pause the aeration operation in the bioreactor zone for 3 to 5 minutes;

[0039] S54: After the microwave treatment is completed, restart the aeration and stirring operation.

[0040] Optionally, S6 specifically includes:

[0041] S61: Introduce the biologically treated wastewater into a chemical sedimentation tank, controlling the wastewater flow rate at 2 to 5 m / s. 3 / h;

[0042] S62: Flocculant is added at the same time as the wastewater enters the sedimentation tank. The flocculant is polyferric sulfate or polyaluminum chloride.

[0043] S63: The amount of flocculant added should be controlled between 10 and 50 mg / L;

[0044] S64: After the flocculant is added, the stirring speed is controlled at 30 to 50 rpm, and stirring is continued for 3 to 5 minutes to ensure that the flocculant and phosphorus in the wastewater are fully mixed and reacted to form precipitate;

[0045] S65: After stirring, let it stand for 30 to 60 minutes to allow the sediment to settle fully. The supernatant after sedimentation flows into the subsequent treatment, while the sediment is discharged through the sludge discharge port.

[0046] Optionally, S7 specifically includes:

[0047] S71: The wastewater after chemical precipitation treatment is sent into the microfiltration equipment, and the wastewater flow rate is controlled at 5 to 15 cubic meters per hour.

[0048] S72: The pore size of the microfiltration membrane is set to 0.01 to 0.1 micrometers;

[0049] S73: Maintain the filtration pressure between 0.1 and 0.3 MPa during the filtration process;

[0050] S74: When the microfiltration equipment is running, a backwashing operation shall be performed every 30 minutes. The backwashing water flow rate shall be 3 to 5 cubic meters per hour and the duration shall be 3 to 5 minutes to remove the accumulations on the surface of the microfiltration membrane.

[0051] Optionally, S8 specifically includes:

[0052] S81: The micro-filtered water is transported to the ozone reactor at a flow rate of 10 to 20 cubic meters per hour to ensure full contact with ozone.

[0053] S82: Ozone gas is generated in the ozone reactor by an ozone generator. The ozone dosage is controlled at 5 to 10 mg / L and the dosage time is 5 to 15 minutes to ensure that the ozone reacts fully.

[0054] S83: After ozone treatment, the water flows into the ultraviolet light treatment equipment, and the wavelength of the ultraviolet light irradiation is set to 254nm;

[0055] S84: During the ultraviolet light treatment process, the ultraviolet light intensity is controlled between 30 and 60 mJ / cm. 2The irradiation time is 5 to 10 minutes.

[0056] Optionally, S9 specifically includes:

[0057] S91: Water treated with ozone and ultraviolet light is introduced into the disinfection tank, and the water flow rate is controlled at 5 to 10 cubic meters per hour to ensure sufficient disinfection time.

[0058] S92: Add disinfectant to the disinfection tank. Sodium hypochlorite or chlorine dioxide should be selected as the disinfectant, and the concentration of the disinfectant should be controlled between 0.5 and 2 mg / L.

[0059] S93: After the disinfectant is thoroughly mixed with water, the contact time should be maintained for 10 to 30 minutes;

[0060] S94: After disinfection, measure the residual chlorine concentration in the water and ensure that the residual chlorine concentration is below 0.5 mg / L before discharge.

[0061] The beneficial effects of this invention are:

[0062] This invention solves the problems of unstable granular sludge formation and incomplete nitrogen and phosphorus removal in existing technologies by organically combining multiple steps such as ultrasonic treatment, nutrient balance regulation, intermittent aeration, microwave enhancement, and chemical precipitation.

[0063] This invention enhances the structural stability of granular sludge by incorporating periodic microwave treatment during the biological reaction process, reducing the possibility of sludge disintegration and improving the efficiency of biological treatment. Furthermore, subsequent chemical precipitation and microfiltration further remove dissolved phosphorus and fine suspended solids from wastewater, ensuring that the treated water meets discharge standards. Attached Figure Description

[0064] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0065] Figure 1 This is a schematic diagram of a wastewater treatment process according to an embodiment of the present invention;

[0066] Figure 2 This is a schematic diagram of the periodic microwave processing flow according to an embodiment of the present invention. Detailed Implementation

[0067] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. It should also be noted that, to make the embodiments more comprehensive, the following embodiments are the best and preferred embodiments, and those skilled in the art can use other alternative methods to implement some well-known technologies; moreover, the accompanying drawings are only for more specific description of the embodiments and are not intended to specifically limit the present invention.

[0068] It should be noted that the use of terms such as "an embodiment," "an embodiment," "an exemplary embodiment," and "some embodiments" in the specification indicates that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments (whether explicitly described or not) should be within the knowledge of those skilled in the art.

[0069] Generally, terms can be understood at least partly from their use in context. For example, depending at least partly on the context, the term "one or more" as used herein can be used to describe any feature, structure, or characteristic in a singular sense, or a combination of features, structures, or characteristics in a plural sense. Additionally, the term "based on" can be understood not necessarily to convey an exclusive set of factors, but rather, alternatively, depending at least partly on the context, to allow for the presence of other factors that are not necessarily explicitly described.

[0070] Example 1

[0071] like Figures 1-2 As shown, an aerobic granular sludge wastewater treatment process includes the following steps:

[0072] S1: Ultrasonic treatment of raw wastewater breaks down large organic molecules in the wastewater to improve its biodegradability.

[0073] S2: Perform preliminary screening on the ultrasonically treated wastewater to remove large suspended solids and easily deposited matter;

[0074] S3: Adjust the pH value of the wastewater after screening and add nutrients to maintain nutrient balance;

[0075] S4: Inject the adjusted wastewater into the biological reaction zone containing pre-cultured aerobic granular sludge and perform intermittent aeration to promote microbial activity and sludge particle maturation.

[0076] S5: Microwave treatment is performed periodically during the biological reaction process to enhance the structural stability of sludge particles;

[0077] S6: Chemically precipitate the biologically treated wastewater and add a predetermined amount of flocculant to remove dissolved phosphorus;

[0078] S7: Micro-filter the wastewater that has undergone biological and chemical treatment to remove residual sludge particles and fine suspended solids;

[0079] S8: The micro-filtered water is treated with ozone and ultraviolet light to degrade residual recalcitrant organic matter;

[0080] S9: Perform end-of-pipe disinfection on the treated water to ensure it meets discharge standards.

[0081] S1 specifically includes:

[0082] S11: Preheat the raw wastewater before it enters the ultrasonic treatment process, and adjust the temperature to 25 degrees Celsius to optimize the efficiency of ultrasonic treatment.

[0083] S12: The preheated wastewater is introduced into the ultrasonic reactor, where the frequency of the ultrasonic equipment is set at 30kHz and the power density is controlled at 0.8W / cm³. 2 ;

[0084] S13: The duration of ultrasonic treatment is 10 minutes to ensure that large organic molecules in the wastewater are fully broken down, thereby improving the efficiency and effectiveness of subsequent biological treatment.

[0085] S2 specifically includes:

[0086] S21: The ultrasonically treated wastewater is transported to the preliminary screening station, where it is physically intercepted using a rotating screen;

[0087] S22: The mesh size of the screen is set to 0.7 mm to capture and remove large suspended solids and easily deposited matter;

[0088] S23: The flow rate of the screening operation is controlled at 150 cubic meters per hour to ensure that the sewage has sufficient contact time and shear force when it flows through the screen to improve the removal efficiency.

[0089] S24: The screened wastewater is collected and diverted to the next treatment stage, while the screened solid waste is periodically removed from the screen.

[0090] S3 specifically includes:

[0091] S31: Preliminary determination of the pH value of the screened wastewater, specifically using an online pH meter for continuous monitoring;

[0092] S32: The target pH value is adjusted to 7.0;

[0093] S33: Added nutrients, including nitrogen and phosphorus sources. The nitrogen source is selected from urea, and the phosphorus source is selected from potassium dihydrogen phosphate.

[0094] S34: The added nutrients are formulated according to the ratio of chemical oxygen demand (COD). Specifically, the ratio of nitrogen to phosphorus is COD:N = 100:5:1, which means that 5 grams of nitrogen and 1 gram of phosphorus need to be added for every 100 grams of COD.

[0095] S4 specifically includes:

[0096] S41: The wastewater with adjusted pH and nutrients is pumped to the biological reaction zone at a fixed flow rate of 2m. 3 / h;

[0097] S42: The biological reaction zone is pre-filled with aerobic granular sludge, and the initial concentration of the sludge is controlled at 4000 mg / L;

[0098] S43: Oxygen is supplied using an intermittent aeration method. Each aeration cycle consists of 10 minutes of continuous aeration and 5 minutes of aeration stop. The aeration operation uses a blower to provide the necessary oxygen.

[0099] S44: During aeration, maintain the dissolved oxygen concentration at 3 mg / L, manually monitor and adjust the oxygen supply to maintain suitable biological activity;

[0100] S45: After aeration, allow the sludge particles to settle naturally.

[0101] S5 specifically includes:

[0102] S51: A microwave transmitter is installed in the bioreactor to ensure that microwave energy uniformly covers the entire reaction zone; and the frequency of microwave treatment is set to 2.45 GHz;

[0103] S52: The duration of each microwave treatment is set to 60 seconds, and microwave treatment is performed every 40 minutes to avoid overheating or negative impact on microbial activity.

[0104] S53: Before each microwave treatment begins, pause the aeration operation in the bioreactor zone for 4 minutes to reduce mechanical interference and ensure that microwave energy is transferred to the sludge particles more efficiently.

[0105] S54: After microwave treatment, restart aeration and stirring to ensure that the sludge particles continue to maintain a good dissolved oxygen environment and microbial activity.

[0106] S6 specifically includes:

[0107] S61: Introduce the biologically treated wastewater into a chemical sedimentation tank, controlling the wastewater flow rate at 3m. 3 / h, to ensure sufficient contact time;

[0108] S62: Flocculant is added at the same time as the wastewater enters the sedimentation tank. The flocculant is polyferric sulfate.

[0109] S63: The amount of flocculant added should be controlled at 30 mg / L;

[0110] S64: After adding the flocculant, the stirring speed is controlled at 40 rpm and stirred continuously for 4 minutes to ensure that the flocculant and phosphorus in the wastewater are fully mixed and reacted to form precipitate;

[0111] S65: After stirring, let it stand for 45 minutes to allow the sediment to settle fully. The supernatant after sedimentation flows into the subsequent treatment, while the sediment is discharged through the sludge discharge port.

[0112] S7 specifically includes:

[0113] S71: The wastewater after chemical precipitation treatment is sent into the microfiltration equipment, and the wastewater flow rate is controlled at 10 cubic meters per hour to ensure appropriate filtration speed and pressure.

[0114] S72: The pore size of the microfiltration membrane is set to 0.05 micrometers to effectively filter out residual sludge particles and fine suspended solids in wastewater;

[0115] S73: Maintain the filtration pressure at 0.2MPa during the filtration process to ensure the effective operation of the microfiltration membrane and avoid excessive clogging of the membrane surface;

[0116] S74: When the microfiltration equipment is running, a backwashing operation shall be performed every 30 minutes. The backwashing water flow rate is 4 cubic meters per hour and the duration is 4 minutes to remove the accumulation on the surface of the microfiltration membrane.

[0117] S8 specifically includes:

[0118] S81: The micro-filtered water is transported to the ozone reactor at a flow rate of 15 cubic meters per hour to ensure full contact with ozone.

[0119] S82: In the ozone reactor, ozone gas is generated by an ozone generator. The ozone dosage is controlled at 8 mg / L and the dosage time is 10 minutes to ensure that the ozone reacts fully and oxidizes the recalcitrant organic matter in the water.

[0120] S83: After ozone treatment, the water flows into the ultraviolet light treatment equipment, and the wavelength of ultraviolet light irradiation is set to 254nm, which is suitable for breaking the chemical bonds in the residual organic molecules;

[0121] S84: During the ultraviolet light treatment process, the ultraviolet light intensity is controlled at 45 mJ / cm. 2 The irradiation time is 8 minutes to ensure that the ultraviolet rays can penetrate the water and achieve effective degradation.

[0122] S9 specifically includes:

[0123] S91: Water treated with ozone and ultraviolet light is introduced into the disinfection tank, and the water flow rate is controlled at 7 cubic meters per hour to ensure sufficient disinfection time.

[0124] S92: Add disinfectant to the disinfection tank. Sodium hypochlorite is selected as the disinfectant, and the concentration of the disinfectant is controlled at 1 mg / L.

[0125] S93: After the disinfectant is thoroughly mixed with water, the contact time should be maintained for 20 minutes to ensure that microorganisms, pathogens and other residual harmful substances in the water are fully inactivated;

[0126] S94: After disinfection, measure the residual chlorine concentration in the water and ensure that the residual chlorine concentration is 0.2 mg / L before discharge; ensure that the effluent meets the national or local wastewater discharge standards.

[0127] Example 2

[0128] S1: The raw wastewater is preheated to 20℃ and then fed into the ultrasonic reactor. The frequency of the ultrasonic equipment is set to 25kHz, and the power density is controlled at 0.5W / cm³. 2 The treatment time is set to 5 minutes to ensure that the large organic molecules in the wastewater are fully broken down, which will facilitate subsequent treatment.

[0129] S2: The wastewater treated by ultrasound is initially screened through a rotating screen with a mesh size of 0.5 mm and a processing flow rate of 100 cubic meters per hour. During this process, large suspended solids and easily deposited solids in the wastewater are effectively removed, and the screened solid waste will be removed periodically.

[0130] S3: The screened wastewater was continuously monitored by an online pH meter. The pH value was found to be 7.8. Hydrochloric acid was added to adjust the pH value to 6.5. Subsequently, ammonium nitrate was added as a nitrogen source and diammonium phosphate as a phosphorus source in a ratio of COD = 100:5:1 to ensure the nitrogen and phosphorus nutrient balance in the wastewater.

[0131] S4: After pH adjustment and nutrient replenishment, the wastewater is transported to the aerobic granular sludge biological reaction zone at a flow rate of 1 cubic meter / hour. The reaction zone is pre-filled with aerobic granular sludge with an initial concentration of 3000 mg / L. Intermittent aeration is adopted, with each aeration cycle including 10 minutes of aeration and 5 minutes of aeration stop, maintaining the dissolved oxygen concentration at 2 mg / L to ensure sludge activity.

[0132] S5: During the biological reaction, microwave treatment is performed every 30 minutes, with the microwave frequency set to 2.45 GHz and each treatment lasting 30 seconds; before microwave treatment, aeration is paused for 3 minutes, and aeration is resumed after the treatment is completed;

[0133] S6: The biologically treated wastewater is transported to the sedimentation tank at a flow rate of 2 cubic meters per hour. At the same time, 10 mg / L of polyaluminum chloride is added as a flocculant. The stirring speed is set to 30 rpm and the stirring time is 3 minutes to ensure that the flocculant and the dissolved phosphorus in the wastewater are fully mixed and reacted. After stirring, the mixture is allowed to settle for 30 minutes.

[0134] S7: The settled wastewater is sent to the microfiltration equipment with a flow rate of 5 cubic meters per hour. The pore size of the microfiltration membrane is set to 0.01 micrometers, and the filtration pressure is maintained at 0.1 MPa. In order to maintain the operating efficiency of the microfiltration equipment, a backwashing operation is performed every 30 minutes. The backwashing water flow rate is 3 cubic meters per hour, and the backwashing time is 3 minutes.

[0135] S8: The microfiltered water is fed into the ozone reactor at a flow rate controlled at 10 cubic meters per hour. The ozone dosage is set at 5 mg / L, and the treatment time is 5 minutes. After ozone treatment, the water enters the ultraviolet (UV) light treatment equipment. The UV light irradiation wavelength is 254 nm, and the UV light intensity is set at 30 mJ / cm². 2 The processing time is 5 minutes;

[0136] S9: Finally, the water treated with ozone and ultraviolet light is transported to the disinfection tank, with the flow rate controlled at 5 cubic meters per hour. 0.5 mg / L of chlorine dioxide is added as a disinfectant, and the disinfection time is set to 10 minutes. The residual chlorine concentration in the water is 0.4 mg / L, which meets the discharge standard.

[0137] Example 3

[0138] S1: The raw wastewater is preheated to 30℃ and then fed into the ultrasonic reactor. The frequency of the ultrasonic equipment is set to 35kHz, and the power density is controlled at 1.0W / cm³. 2 The treatment time is set to 15 minutes to ensure that the large organic molecules in the wastewater are fully broken down, which will facilitate subsequent treatment.

[0139] S2: The wastewater treated by ultrasound is initially screened through a rotating screen with a mesh size of 1.0 mm and a processing flow rate of 200 cubic meters per hour. During this process, large suspended solids and easily deposited solids in the wastewater are effectively removed, and the screened solid waste will be removed periodically.

[0140] S3: The screened wastewater was continuously monitored by an online pH meter. The pH value was found to be 8.1. Hydrochloric acid was added to adjust the pH value to 7.5. Subsequently, urea was added as a nitrogen source and potassium dihydrogen phosphate as a phosphorus source in a ratio of COD = 100:5:1 to ensure the nitrogen and phosphorus nutrient balance in the wastewater.

[0141] S4: After pH adjustment and nutrient replenishment, the wastewater is transported to the aerobic granular sludge biological reaction zone at a flow rate of 3 cubic meters per hour. The reaction zone is pre-filled with aerobic granular sludge with an initial concentration of 5000 mg / L. Intermittent aeration is adopted, with each aeration cycle including 10 minutes of aeration and 5 minutes of aeration stop, maintaining the dissolved oxygen concentration at 4 mg / L to ensure sludge activity.

[0142] S5: During the biological reaction, microwave treatment is performed every 60 minutes, with the microwave frequency set to 2.45 GHz and each treatment lasting 90 seconds; before microwave treatment, aeration is paused for 5 minutes, and aeration is resumed after the treatment is completed;

[0143] S6: The biologically treated wastewater is transported to the sedimentation tank with a flow rate of 5 cubic meters per hour. At the same time, 50 mg / L of polyferric sulfate is added as a flocculant. The stirring speed is set to 50 rpm and the stirring time is 5 minutes to ensure that the flocculant and the dissolved phosphorus in the wastewater are fully mixed and reacted. After stirring, the mixture is allowed to settle for 60 minutes.

[0144] S7: The settled wastewater is sent to the microfiltration equipment with a flow rate controlled at 15 cubic meters per hour. The pore size of the microfiltration membrane is set to 0.1 micrometers, and the filtration pressure is maintained at 0.3 MPa. In order to maintain the operating efficiency of the microfiltration equipment, a backwashing operation is performed every 30 minutes. The backwashing water flow rate is 5 cubic meters per hour, and the backwashing time is 5 minutes.

[0145] S8: The microfiltered water is fed into the ozone reactor at a flow rate controlled at 20 cubic meters per hour. The ozone dosage is set at 10 mg / L, and the treatment time is 15 minutes. After ozone treatment, the water enters the ultraviolet (UV) light treatment equipment. The UV light irradiation wavelength is 254 nm, and the UV light intensity is set at 60 mJ / cm². 2 The processing time is 10 minutes;

[0146] S9: Finally, the water treated with ozone and ultraviolet light is transported to the disinfection tank, with the flow rate controlled at 10 cubic meters per hour. 2 mg / L of sodium hypochlorite is added as a disinfectant, and the disinfection time is set to 30 minutes. The residual chlorine concentration in the water is 0.5 mg / L, which meets the discharge standards.

[0147] Table 1 Comparison of performance parameters of the embodiments

[0148]

[0149]

[0150] As can be seen from Table 1 above, the COD removal rate of Example 1 was 97%, higher than 90% of Example 2 and 95% of Example 3, showing the best removal effect; the ammonia nitrogen removal rate of Example 1 was 99%, much higher than 92% of Example 2, and slightly higher than 98% of Example 3, demonstrating excellent performance; the phosphorus removal rate of Example 1 was 98%, significantly higher than 90% of Example 2, and also better than 96% of Example 3; the sludge yield of Example 1 was 0.3 kg / m³. 3 This is lower than the other two embodiments, meaning less sludge is generated and the operation is more efficient; the energy consumption of Embodiment 1 is 0.6 kWh / m³. 3 Compared to 0.8 kWh / m³ in Example 2 3 And 1.0 kWh / m in Example 3 3 It is more energy-efficient; the effluent pH value of Example 1 is 7.0, which is neutral water quality and suitable for discharge standards; the residual chlorine concentration of Example 1 is 0.2 mg / L, which is lower than the other two examples, ensuring higher disinfection effect and environmental safety; in summary, Example 1 performs best in terms of removal effect, sludge production rate and energy consumption, and is the optimal implementation plan.

[0151] Table 2 Comparison of other performance parameters

[0152] Comparison Projects Example 1 Example 2 Example 3 Effluent turbidity (NTU) 0.3 0.8 0.5 Bioreaction efficiency (mg / L·h) 150 120 140 Sludge settling velocity (m / h) 1.2 1 1.1 Phosphorus content in effluent (mg / L) 0.1 0.2 0.15 Redox potential (mV) 450 400 420 Suspended solids removal rate (%) 99 95 97 Disinfection residue (mg / L) 0.05 0.1 0.08

[0153] As can be seen from Table 2 above, the effluent turbidity of Example 1 was 0.3 NTU, which was much lower than 0.8 NTU of Example 2 and 0.5 NTU of Example 3, indicating that the treated water was clearer; the biological reaction efficiency of Example 1 was 150 mg / L·h, slightly higher than 120 mg / L·h of Example 2 and 140 mg / L·h of Example 3, showing higher treatment efficiency; the sludge settling velocity of Example 1 was 1.2 m / h, better than 1.0 m / h of Example 2 and 1.1 m / h of Example 3, showing better sludge settling performance; the phosphorus content of the effluent of Example 1 was 0.1 mg / L. The phosphorus removal efficiency of Example 1 is significantly better than that of Example 2 (0.2 mg / L) and Example 3 (0.15 mg / L), indicating a superior phosphorus removal effect. The oxidation-reduction potential of Example 1 is 450 mV, higher than that of Example 2 (400 mV) and Example 3 (420 mV), indicating a stronger oxidation capacity during water treatment. The suspended solids removal rate of Example 1 is 99%, significantly higher than that of Example 2 (95%) and Example 3 (97%), demonstrating the best removal effect. The disinfection residue of Example 1 is 0.05 mg / L, lower than that of Example 2 (0.1 mg / L) and Example 3 (0.08 mg / L), ensuring safer water discharge. In summary, Example 1 performs best in several key performance aspects, including effluent turbidity, biological reaction efficiency, sludge settling velocity, and effluent phosphorus content, and remains the optimal implementation scheme.

[0154] This invention encompasses any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of this invention. To provide the public with a thorough understanding of this invention, specific details are described in detail in the following preferred embodiments; however, those skilled in the art will fully understand the invention even without these details. Furthermore, to avoid unnecessary misunderstanding of the essence of this invention, well-known methods, processes, procedures, components, and circuits are not described in detail.

[0155] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An aerobic granular sludge wastewater treatment process, characterized in that, Includes the following steps: S1: Ultrasonic treatment of raw wastewater to break down large organic molecules in the wastewater; S2: Perform preliminary screening on the ultrasonically treated wastewater to remove large suspended solids and easily deposited matter; S3: Adjust the pH value of the wastewater after screening and add nutrients to maintain nutrient balance; S4: Inject the adjusted wastewater into the biological reaction zone containing pre-cultured aerobic granular sludge and perform intermittent aeration to enhance microbial activity and promote sludge particle maturation. S5: Microwave treatment is performed periodically during the biological reaction process to enhance the structural stability of sludge particles; S5 specifically includes: S51: A microwave transmitter is installed in the bioreactor; and the frequency of the microwave treatment is set to 2.45 GHz; S52: The duration of each microwave treatment is set to 30 to 90 seconds, and microwave treatment is performed every 30 to 60 minutes; S53: Before each microwave treatment begins, pause the aeration operation in the bioreactor zone for 3 to 5 minutes; S54: After the microwave treatment is completed, restart the aeration and stirring operation; S6: Chemically precipitate the biologically treated wastewater and add a predetermined amount of flocculant to remove dissolved phosphorus; S7: Micro-filter the wastewater that has undergone biological and chemical treatment to remove residual sludge particles and fine suspended solids; S8: The micro-filtered water is treated with ozone and ultraviolet light to degrade residual recalcitrant organic matter; S9: Perform end-of-pipe disinfection on the treated water to ensure it meets discharge standards.

2. The aerobic granular sludge wastewater treatment process according to claim 1, characterized in that, S1 specifically includes: S11: Preheat the raw wastewater before it enters the ultrasonic treatment process, and adjust the temperature to 20 to 30 degrees Celsius. S12: Introduce the preheated wastewater into the ultrasonic reactor, wherein the frequency of the ultrasonic equipment is set to 25kHz to 35kHz and the power density is controlled to 0.5 to 1.0W / cm². S13: The duration of ultrasonic treatment is 5 to 15 minutes to ensure that large molecular organic matter in the wastewater is fully broken down.

3. The aerobic granular sludge wastewater treatment process according to claim 1, characterized in that, S2 specifically includes: S21: The ultrasonically treated wastewater is transported to the preliminary screening station, where it is physically intercepted using a rotating screen; S22: The mesh size of the screen is set to 0.5 to 1.0 mm to capture and remove large suspended solids and easily deposited matter; S23: The flow rate of the screening operation is controlled at 100 to 200 cubic meters per hour; S24: The screened wastewater is collected and diverted to the next treatment stage, while the screened solid waste is periodically removed from the screen.

4. The aerobic granular sludge wastewater treatment process according to claim 1, characterized in that, S3 specifically includes: S31: Preliminary determination of the pH value of the screened wastewater, and continuous monitoring using an online pH meter; S32: If the pH value is below 6.5, sodium hydroxide will be automatically added for adjustment; if the pH value is above 7.5, hydrochloric acid will be added for adjustment, with the target pH value being 6.5 to 7.

5. S33: Add nutrients, including nitrogen and phosphorus sources, wherein the nitrogen source is selected from urea or ammonium nitrate, and the phosphorus source is selected from potassium dihydrogen phosphate or diammonium phosphate; S34: The added nutrients are formulated according to the ratio of chemical oxygen demand (COD), that is, 5 grams of nitrogen and 1 gram of phosphorus need to be added for every 100 grams of COD.

5. The aerobic granular sludge wastewater treatment process according to claim 1, characterized in that, S4 specifically includes: S41: The wastewater with adjusted pH and nutrients is pumped to the biological reaction zone through a pump with a fixed flow rate of 1-3 m³ / h. S42: The biological reaction zone is pre-filled with aerobic granular sludge, and the initial concentration of aerobic granular sludge is controlled at 3000 to 5000 mg / L; S43: Oxygen is supplied using an intermittent aeration method, with each aeration cycle consisting of 10 minutes of continuous aeration and 5 minutes of aeration stop; S44: During aeration, maintain the dissolved oxygen concentration at 2 to 4 mg / L to maintain suitable biological activity; S45: After aeration, allow the sludge particles to settle naturally.

6. The aerobic granular sludge wastewater treatment process according to claim 1, characterized in that, S6 specifically includes: S61: Introduce the biologically treated wastewater into a chemical sedimentation tank, and control the wastewater flow rate at 2 to 5 m³ / h; S62: Flocculant is added at the same time as the wastewater enters the chemical sedimentation tank. The flocculant is polyferric sulfate or polyaluminum chloride. S63: The amount of flocculant added should be controlled between 10 and 50 mg / L; S64: After the flocculant is added, the stirring speed is controlled at 30 to 50 rpm, and stirring is continued for 3 to 5 minutes to ensure that the flocculant and phosphorus in the wastewater are fully mixed and reacted to form precipitate; S65: After stirring, let it stand for 30 to 60 minutes to allow the sediment to settle fully. The supernatant after sedimentation flows into the subsequent treatment, while the sediment is discharged through the sludge discharge port.

7. The aerobic granular sludge wastewater treatment process according to claim 1, characterized in that, Specifically, S7 includes: S71: The wastewater after chemical precipitation treatment is sent into the microfiltration equipment, and the wastewater flow rate is controlled at 5 to 15 cubic meters per hour. S72: The pore size of the microfiltration membrane is set to 0.01 to 0.1 micrometers; S73: Maintain the filtration pressure between 0.1 and 0.3 MPa during the filtration process; S74: When the microfiltration equipment is running, a backwashing operation shall be performed every 30 minutes. The backwashing water flow rate shall be 3 to 5 cubic meters per hour and the duration shall be 3 to 5 minutes to remove the accumulations on the surface of the microfiltration membrane.

8. The aerobic granular sludge wastewater treatment process according to claim 1, characterized in that, S8 specifically includes: S81: The micro-filtered water is transported to the ozone reactor at a flow rate of 10 to 20 cubic meters per hour to ensure full contact with ozone. S82: Ozone gas is generated in the ozone reactor by an ozone generator. The ozone dosage is controlled at 5 to 10 mg / L and the dosage time is 5 to 15 minutes to ensure that the ozone reacts fully. S83: After ozone treatment, the water flows into the ultraviolet light treatment equipment, and the wavelength of the ultraviolet light irradiation is set to 254nm; S84: During the ultraviolet light treatment process, the ultraviolet light intensity is controlled at 30 to 60 mJ / cm², and the irradiation time is 5 to 10 minutes.

9. The aerobic granular sludge wastewater treatment process according to claim 1, characterized in that, S9 specifically includes: S91: Water treated with ozone and ultraviolet light is introduced into the disinfection tank, and the water flow rate is controlled at 5 to 10 cubic meters per hour to ensure sufficient disinfection time. S92: Add disinfectant to the disinfection tank. Sodium hypochlorite or chlorine dioxide should be selected as the disinfectant, and the concentration of the disinfectant should be controlled between 0.5 and 2 mg / L. S93: After the disinfectant is thoroughly mixed with water, the contact time should be maintained for 10 to 30 minutes; S94: After disinfection, measure the residual chlorine concentration in the water and ensure that the residual chlorine concentration is below 0.5 mg / L before discharge.

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