Aerobic granular sludge sewage treatment process

Abstract

The invention relates to the technical field of environmental engineering, in particular to an aerobic granular sludge sewage treatment process which comprises the following steps: S1, performing ultrasonic treatment on raw sewage; s2, preliminarily screening the sewage subjected to ultrasonic treatment; s3, adjusting the pH value of the screened sewage, and adding nutrient substances; s4, injecting the adjusted sewage into a biological reaction zone containing pre-cultured aerobic granular sludge, and carrying out intermittent aeration operation; s5, regularly performing microwave treatment in the biological reaction process; s6, carrying out chemical precipitation on the sewage subjected to biological treatment; s7, performing microfiltration on the sewage subjected to biological treatment and chemical treatment; s8, performing ozone and ultraviolet light treatment on the water subjected to microfiltration; s9, carrying out tail end disinfection on the treated water; according to the invention, the formation and stabilization of aerobic granular sludge are effectively promoted, the removal efficiency of pollutants such as organic matters, nitrogen and phosphorus in sewage is improved, and the effluent quality is ensured to reach the standard.

Description

Technical Field

[0001] The invention relates to the technical field of environmental engineering, and in particular to an aerobic granular sludge sewage treatment process. Background Art

[0002] With the development of social economy and the acceleration of urbanization, sewage treatment has become one of the important topics in the field of environmental protection. Traditional sewage treatment processes, such as activated sludge method, have achieved certain results in treating organic pollutants, nitrogen, phosphorus and other aspects in sewage, but they still face a series of challenges in the operation process, such as sludge bulking, large sludge production, low nitrogen and phosphorus removal efficiency in sewage, etc. In recent years, aerobic granular sludge technology has gradually become a research hotspot in the field of sewage treatment due to its advantages such as good sludge settling, high treatment efficiency and small system footprint. This technology forms granular sludge through the natural aggregation of aerobic microorganisms, can maintain stable operation under high load conditions, and has a high sludge recovery rate. However, in actual 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 is still one of the difficulties in the large-scale promotion of this technology.

[0003] The existing aerobic granular sludge technology still has many technical bottlenecks in the application process. First, the degradation of macromolecular organic matter in sewage is difficult, which affects the biological activity and formation process of aerobic granular sludge. Secondly, in high-load sewage treatment, the balance control of nutrients such as nitrogen and phosphorus is not precise enough, resulting in unsatisfactory nitrogen and phosphorus removal effects. In addition, the structural stability of sludge particles is poor and is easily affected by external conditions such as aeration methods and chemicals, thus affecting the efficiency and operating costs of the entire treatment system. Therefore, it is particularly necessary to develop an aerobic granular sludge sewage treatment process that can effectively solve these problems. Summary of the invention

[0004] Based on the above purpose, the present invention provides an aerobic granular sludge sewage treatment process.

[0005] An aerobic granular sludge sewage treatment process comprises the following steps:

[0006] S1: Ultrasonic treatment of raw sewage to break down macromolecular organic substances in sewage;

[0007] S2: Preliminary screening of ultrasonically treated wastewater to remove large suspended solids and sediments;

[0008] S3: Adjust the pH value of the screened wastewater and add nutrients to maintain nutritional balance;

[0009] S4: injecting the adjusted sewage into the biological reaction zone containing pre-cultured aerobic granular sludge, and performing intermittent aeration operation to promote microbial activity and maturation of sludge particles;

[0010] S5: During the biological reaction process, microwave treatment is performed regularly to enhance the structural stability of sludge particles;

[0011] S6: chemically precipitating the biologically treated wastewater by adding a predetermined amount of flocculant to remove dissolved phosphorus;

[0012] S7: Microfiltration of biologically and chemically treated sewage to remove residual sludge particles and fine suspended matter;

[0013] S8: treating the micro-filtered water with ozone and ultraviolet light to degrade the residual refractory organic matter;

[0014] S9: Perform terminal disinfection on the treated water to ensure that it meets the discharge standards.

[0015] Optionally, the S1 specifically includes:

[0016] S11: preheating the raw sewage before entering the ultrasonic treatment, adjusting the temperature to 20 to 30 degrees Celsius to optimize the efficiency of the ultrasonic treatment;

[0017] S12: The preheated sewage is introduced into an ultrasonic reactor, wherein the frequency of the ultrasonic equipment is set at 25kHz to 35kHz, and the power density is controlled at 0.5 to 1.0W / cm 2 ;

[0018] S13: The duration of ultrasonic treatment is 5 to 15 minutes, ensuring that the macromolecular organic matter in the sewage is fully broken down.

[0019] Optionally, the S2 specifically includes:

[0020] S21: The ultrasonically treated sewage is transported to a preliminary screening station for physical interception using a rotary screen;

[0021] S22: The mesh size is set to 0.5 to 1.0 mm to capture and remove large suspended solids and sediment-prone solids;

[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 directed to the next treatment stage, while the screened solid waste is removed from the screen regularly.

[0024] Optionally, the S3 specifically includes:

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

[0026] S32: If the pH value is lower than 6.5, sodium hydroxide is automatically added for adjustment; if the pH value is higher than 7.5, hydrochloric acid is added for adjustment, and the adjusted target pH value is 6.5 to 7.5;

[0027] S33: adding nutrients, including a nitrogen source and a phosphorus source, 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 prepared according to the ratio of chemical oxygen demand (COD). The specific ratio of nitrogen and phosphorus added is COD:N=100:5:1, that is, 5 grams of nitrogen and 1 gram of phosphorus are required for every 100 grams of COD.

[0029] Optionally, the S4 specifically includes:

[0030] S41: The sewage with adjusted pH and nutrients is transported to the biological reaction area through a fixed flow rate pump, and the flow rate is set to 1-3m 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: intermittent aeration is used for oxygen supply, and each aeration cycle includes 10 minutes of continuous aeration and 5 minutes of aeration suspension;

[0033] S44: During aeration, maintain dissolved oxygen concentration between 2 and 4 mg / L to maintain appropriate biological activity;

[0034] S45: Allow the sludge particles to settle naturally after aeration.

[0035] Optionally, the S5 specifically includes:

[0036] S51: arranging a microwave transmitter in the bioreactor; and setting the frequency of microwave treatment to 2.45 GHz;

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

[0038] S53: before each microwave treatment begins, suspending the aeration operation in the biological reaction zone for 3 to 5 minutes;

[0039] S54: After the microwave treatment is completed, the aeration and stirring operations are restarted.

[0040] Optionally, the S6 specifically includes:

[0041] S61: The biologically treated sewage is introduced into the chemical sedimentation tank, and the flow rate of the sewage is controlled at 2 to 5m 3 / h;

[0042] S62: When the sewage enters the sedimentation tank, a flocculant is added, and the flocculant is polyferric sulfate or polyaluminium chloride;

[0043] S63: The amount of flocculant added is 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 the stirring is continued for 3 to 5 minutes to ensure that the flocculant is fully mixed with the phosphorus in the sewage to react and form a precipitate;

[0045] S65: After the stirring is completed, the mixture is allowed to settle for 30 to 60 minutes so that the sediment can fully sink. The supernatant after the sedimentation flows into the subsequent treatment, and the sediment is discharged through the mud outlet for treatment.

[0046] Optionally, the S7 specifically includes:

[0047] S71: The sewage after chemical precipitation treatment is sent to the microfiltration equipment, and the sewage 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 microns;

[0049] S73: maintaining the filtration pressure at 0.1 to 0.3 MPa during the filtration process;

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

[0051] Optionally, the S8 specifically includes:

[0052] S81: The micro-filtered water is transported to the ozone reactor, and the water flow rate is controlled at 10 to 20 cubic meters per hour to ensure sufficient exposure to ozone;

[0053] S82: In the ozone reactor, ozone gas is generated by an ozone generator, and the dosage of ozone is controlled at 5 to 10 mg / L, and the dosage time is 5 to 15 minutes to ensure that the ozone fully reacts;

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

[0055] S84: During the UV treatment process, the UV intensity is controlled at 30 to 60 mJ / cm 2, the irradiation time is 5 to 10 minutes.

[0056] Optionally, the S9 specifically includes:

[0057] S91: Introduce the water treated with ozone and ultraviolet light into the disinfection tank, and control the water flow rate at 5 to 10 cubic meters per hour to ensure sufficient disinfection time;

[0058] S92: Add disinfectant to the disinfection pool. The disinfectant is sodium hypochlorite or chlorine dioxide. The concentration of the disinfectant is controlled at 0.5 to 2 mg / L.

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

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

[0061] Beneficial effects of the present invention:

[0062] The present invention solves the problems of the difficulty in stable formation of granular sludge and incomplete removal of nitrogen and phosphorus in the prior art by organically combining multiple steps such as ultrasonic treatment, nutrient balance adjustment, intermittent aeration, microwave enhancement and chemical precipitation.

[0063] The present invention, by adding regular microwave treatment in the biological reaction process, enhances the structural stability of granular sludge, reduces the possibility of sludge disintegration, and improves the efficiency of biological treatment; and further removes soluble phosphorus and fine suspended matter in sewage through subsequent chemical precipitation and microfiltration, ensuring that the treated water quality meets the discharge standard. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only for the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0065] Figure 1 A schematic diagram of a sewage treatment process according to an embodiment of the present invention;

[0066] Figure 2 Schematic diagram of the process of periodically performing microwave treatment according to an embodiment of the present invention. DETAILED DESCRIPTION

[0067] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. At the same time, it is explained here that in order to make the embodiments more detailed, the following embodiments are the best and preferred embodiments, and those skilled in the art may also adopt other alternatives to implement some known technologies; and 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 references to "one embodiment", "an embodiment", "an exemplary embodiment", "some embodiments" and the like in the specification indicate that the embodiments described may include specific features, structures or characteristics, but not every embodiment may include the specific features, structures or characteristics. In addition, when a specific feature, structure or characteristic is described in conjunction with an embodiment, it should be within the knowledge of a person skilled in the art to implement such feature, structure or characteristic in conjunction with other embodiments (whether or not explicitly described).

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

[0070] Example 1

[0071] like Figure 1-Figure 2 As shown, an aerobic granular sludge sewage treatment process comprises the following steps:

[0072] S1: Ultrasonic treatment of raw sewage to break down macromolecular organic matter in the sewage to improve its biodegradability;

[0073] S2: Preliminary screening of ultrasonically treated wastewater to remove large suspended solids and sediments;

[0074] S3: Adjust the pH value of the screened wastewater and add nutrients to maintain nutritional balance;

[0075] S4: injecting the adjusted sewage into the biological reaction zone containing pre-cultured aerobic granular sludge, and performing intermittent aeration operation to promote microbial activity and maturation of sludge particles;

[0076] S5: During the biological reaction process, microwave treatment is performed regularly to enhance the structural stability of sludge particles;

[0077] S6: chemically precipitating the biologically treated wastewater by adding a predetermined amount of flocculant to remove dissolved phosphorus;

[0078] S7: Microfiltration of biologically and chemically treated sewage to remove residual sludge particles and fine suspended matter;

[0079] S8: treating the micro-filtered water with ozone and ultraviolet light to degrade the residual refractory organic matter;

[0080] S9: Perform terminal disinfection on the treated water to ensure that it meets the discharge standards.

[0081] S1 specifically includes:

[0082] S11: preheating the raw sewage before entering the ultrasonic treatment, adjusting the temperature to 25 degrees Celsius to optimize the efficiency of the ultrasonic treatment;

[0083] S12: The preheated sewage 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 / cm 2 ;

[0084] S13: The duration of ultrasonic treatment is 10 minutes, which ensures that the macromolecular organic matter in the sewage is fully broken down to improve the efficiency and effect of subsequent biological treatment.

[0085] S2 specifically includes:

[0086] S21: The ultrasonically treated sewage is transported to a preliminary screening station for physical interception using a rotary screen;

[0087] S22: The mesh size is set to 0.7 mm to capture and remove large suspended solids and sediments;

[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 flowing through the screen to improve removal efficiency;

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

[0090] S3 specifically includes:

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

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

[0093] S33: adding nutrients, including a nitrogen source and a phosphorus source, wherein the nitrogen source is selected from urea, and the phosphorus source is selected from potassium dihydrogen phosphate;

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

[0095] S4 specifically includes:

[0096] S41: The sewage with adjusted pH and nutrients is transported to the biological reaction area through a fixed flow rate pump, and the flow rate is set to 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: Intermittent aeration is used for oxygen supply. Each aeration cycle includes 10 minutes of continuous aeration and 5 minutes of aeration suspension. The aeration operation uses a blower to provide the necessary oxygen.

[0099] S44: During aeration, the dissolved oxygen concentration was maintained at 3 mg / L, and the oxygen supply was manually tested and adjusted to maintain appropriate biological activity;

[0100] S45: Allow the sludge particles to settle naturally after aeration.

[0101] S5 specifically includes:

[0102] S51: arranging a microwave transmitter in the bioreactor to ensure that the microwave energy evenly covers the entire reaction area; and setting the frequency of the microwave treatment to 2.45 GHz;

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

[0104] S53: Before each microwave treatment, the aeration operation in the biological reaction zone was suspended for 4 minutes to reduce mechanical disturbance and ensure that microwave energy was more efficiently transferred to the sludge particles;

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

[0106] S6 specifically includes:

[0107] S61: The biologically treated sewage is introduced into the chemical sedimentation tank, and the flow rate of the sewage is controlled at 3m 3 / h to ensure adequate contact time;

[0108] S62: When the sewage enters the sedimentation tank, flocculant is added, and the flocculant is polyferric sulfate;

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

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

[0111] S65: After the stirring is completed, the mixture is allowed to settle for 45 minutes so that the sediment can fully sink. The supernatant after the sedimentation flows into the subsequent treatment, and the sediment is discharged through the mud discharge port for treatment.

[0112] S7 specifically includes:

[0113] S71: The sewage after chemical precipitation treatment is sent to the microfiltration equipment, and the sewage 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 microns to effectively filter out residual sludge particles and fine suspended matter in sewage;

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

[0116] S74: When the microfiltration equipment is in operation, backwashing is performed every 30 minutes, with a backwashing water flow rate of 4 cubic meters per hour and a duration of 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, and the water flow rate is controlled at 15 cubic meters per hour to ensure sufficient exposure to ozone;

[0119] S82: In the ozone reactor, ozone gas is generated by an ozone generator, and the dosage of ozone is controlled at 8 mg / L, and the dosage time is 10 minutes to ensure that the ozone fully reacts and oxidizes the difficult-to-degrade 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 UV treatment process, the UV intensity was controlled at 45mJ / cm 2 , the irradiation time is 8 minutes to ensure that the ultraviolet rays can deeply treat the water and achieve effective degradation effect.

[0122] S9 specifically includes:

[0123] S91: Introduce the water treated with ozone and ultraviolet light into the disinfection tank, and control the water flow rate at 7 cubic meters per hour to ensure sufficient disinfection time;

[0124] S92: Add disinfectant into the disinfection pool. Sodium hypochlorite is selected as the disinfectant. The concentration of the disinfectant is controlled at 1 mg / L.

[0125] S93: After the disinfectant is fully mixed with water, the contact time is 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 sewage discharge standards.

[0127] Example 2

[0128] S1: The raw sewage is preheated to 20°C and then sent into the ultrasonic reactor. The frequency of the ultrasonic equipment is set to 25kHz and the power density is controlled at 0.5W / cm 2 The treatment time is set to 5 minutes to ensure that the macromolecular organic matter in the sewage is fully broken down to facilitate subsequent treatment;

[0129] S2: The sewage after ultrasonic treatment is initially screened through a rotating screen with a sieve aperture of 0.5 mm and a treatment flow rate of 100 cubic meters per hour. During this process, large suspended solids and easily precipitated solids in the sewage are effectively removed, and the screened solid waste will be removed regularly.

[0130] S3: The screened sewage was continuously monitored by an online pH meter, and the pH value was found to be 7.8. Hydrochloric acid was added to adjust the pH value to 6.5; then, 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 sewage;

[0131] S4: After pH adjustment and nutrient supplementation, the sewage 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. Each aeration cycle includes 10 minutes of aeration and 5 minutes of aeration. The dissolved oxygen concentration is maintained at 2 mg / L to ensure the activity of the sludge.

[0132] S5: During the biological reaction process, microwave treatment was performed every 30 minutes, the microwave frequency was set to 2.45 GHz, and each treatment lasted for 30 seconds; before the microwave treatment, the aeration operation was suspended for 3 minutes, and aeration was resumed after the end;

[0133] S6: The biologically treated sewage is transported to the sedimentation tank, the flow rate is set to 2 cubic meters per hour, and 10 mg / L of polyaluminium 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 soluble phosphorus in the sewage are fully mixed and reacted. After the stirring is completed, it is allowed to settle for 30 minutes;

[0134] S7: The precipitated sewage is sent to the microfiltration equipment, the flow rate is controlled at 5 cubic meters per hour, the pore size of the microfiltration membrane is set to 0.01 microns, and the filtration pressure is maintained at 0.1 MPa. In order to maintain the operating efficiency of the microfiltration equipment, 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 water after microfiltration is sent to the ozone reactor, the flow rate is controlled at 10 cubic meters / hour, the ozone dosage is set to 5 mg / L, and the treatment time is 5 minutes. After ozone treatment, the water enters the ultraviolet light treatment equipment, the ultraviolet light wavelength is 254nm, and the ultraviolet light intensity is set to 30mJ / cm 2 , the processing time is 5 minutes;

[0136] S9: Finally, the water treated with ozone and ultraviolet light is transported to the disinfection pool. The flow rate is controlled at 5 cubic meters per hour. 0.5 mg / L of chlorine dioxide is added as a disinfectant. 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 sewage is preheated to 30°C and then sent into the ultrasonic reactor. The frequency of the ultrasonic equipment is set to 35kHz and the power density is controlled at 1.0W / cm 2 The treatment time is set to 15 minutes to ensure that the macromolecular organic matter in the sewage is fully broken down to facilitate subsequent treatment;

[0139] S2: The wastewater after ultrasonic treatment is initially screened through a rotating screen with a pore size of 1.0 mm and a treatment flow rate of 200 cubic meters per hour. During this process, large suspended solids and sediments in the wastewater are effectively removed, and the screened solid waste will be removed regularly.

[0140] S3: The screened sewage was continuously monitored by an online pH meter, and the pH value was found to be 8.1. Hydrochloric acid was added to adjust the pH value to 7.5; then, 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 sewage;

[0141] S4: After pH adjustment and nutrient supplementation, the sewage 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. Each aeration cycle includes 10 minutes of aeration and 5 minutes of aeration suspension to maintain the dissolved oxygen concentration at 4 mg / L to ensure the activity of the sludge.

[0142] S5: During the biological reaction process, microwave treatment was performed every 60 minutes, the microwave frequency was set to 2.45 GHz, and each treatment lasted for 90 seconds; before the microwave treatment, the aeration operation was suspended for 5 minutes, and aeration was resumed after the microwave treatment;

[0143] S6: The biologically treated sewage is transported to the sedimentation tank, the flow rate is set to 5 cubic meters per hour, and 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 soluble phosphorus in the sewage are fully mixed and reacted. After the stirring is completed, it is allowed to settle for 60 minutes;

[0144] S7: The precipitated sewage is sent to the microfiltration equipment, the flow rate is controlled at 15 cubic meters per hour, the pore size of the microfiltration membrane is set to 0.1 microns, and the filtration pressure is maintained at 0.3 MPa. In order to maintain the operating efficiency of the microfiltration equipment, 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 water after microfiltration is sent to the ozone reactor, the flow rate is controlled at 20 cubic meters / hour, the ozone dosage is set to 10 mg / L, and the treatment time is 15 minutes. After ozone treatment, the water enters the ultraviolet light treatment equipment, the ultraviolet light wavelength is 254nm, and the ultraviolet light intensity is set to 60mJ / cm 2 , the processing time is 10 minutes;

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

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

[0148]

[0149]

[0150] It can be seen from Table 1 that the COD removal rate of Example 1 is 97%, which is higher than 90% of Example 2 and 95% of Example 3, and the removal effect is the best; the ammonia nitrogen removal rate of Example 1 is 99%, which is much higher than 92% of Example 2 and slightly higher than 98% of Example 3, and the performance is excellent; the phosphorus removal rate of Example 1 is 98%, which is significantly higher than 90% of Example 2 and better than 96% of Example 3; the sludge yield of Example 1 is 0.3kg / m 3 , which is lower than the other two embodiments, meaning less sludge is produced and the operation is more efficient; the energy consumption of embodiment 1 is 0.6 kWh / m 3 , compared with 0.8 kWh / m in Example 2 3 and 1.0 kWh / m in Example 3 3 More energy-saving; the effluent pH value of Example 1 is 7.0, which belongs to neutral water quality and meets the discharge standard; the residual chlorine concentration of Example 1 is 0.2 mg / L, which is lower than that of the other two examples, ensuring higher disinfection effect and environmental safety; in summary, Example 1 performs best in removal effect, sludge yield and energy consumption, and is the optimal implementation plan.

[0151] Table 2 Comparison of other performance parameters

[0152] Compare Projects Example 1 Example 2 Example 3 Outlet turbidity (NTU) 0.3 0.8 0.5 Biological reaction efficiency (mg / L·h) 150 120 140 Sludge settling speed (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 matter removal rate (%) 99 95 97 Disinfection residue (mg / L) 0.05 0.1 0.08

[0153] It can be seen from Table 2 that the effluent turbidity of Example 1 is 0.3NTU, which is much lower than 0.8NTU of Example 2 and 0.5NTU of Example 3, indicating that the water quality after treatment is clearer; the biological reaction efficiency of Example 1 is 150mg / L·h, which is slightly higher than 120mg / L·h of Example 2 and 140mg / L·h of Example 3, showing higher treatment efficiency; the sludge settling rate of Example 1 is 1.2m / h, which is better than 1.0m / h of Example 2 and 1.1m / h of Example 3, showing better sludge settling performance; the phosphorus content of the effluent of Example 1 is 0.1mg / L, significantly better than 0.2mg / L of Example 2 and 0.15mg / L of Example 3, indicating that its phosphorus removal effect is better; the redox potential of Example 1 is 450mV, which is higher than 400mV of Example 2 and 420mV of Example 3, indicating that its oxidation ability is stronger during water treatment; the suspended solids removal rate of Example 1 is 99%, which is significantly higher than 95% of Example 2 and 97% of Example 3, and the removal effect is the best; the disinfection residue of Example 1 is 0.05mg / L, which is lower than 0.1mg / L of Example 2 and 0.08mg / L of Example 3, ensuring safer water quality discharge. In summary, Example 1 performs best in multiple key performance aspects such as effluent turbidity, biological reaction efficiency, sludge settling rate, effluent phosphorus content, etc., and is still the best implementation plan.

[0154] The present invention covers any substitution, modification, equivalent method and scheme made on the essence and scope of the present invention. In order to make the public have a thorough understanding of the present invention, specific details are described in detail in the following preferred embodiments of the present invention, but those skilled in the art can fully understand the present invention without the description of these details. In addition, in order to avoid unnecessary confusion about the essence of the present invention, well-known methods, processes, procedures, components and circuits are not described in detail.

[0155] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An aerobic granular sludge sewage treatment process, characterized in that: The following steps are involved: S1: Ultrasonic treatment of raw sewage to break down macromolecular organic substances in sewage; S2: Preliminary screening of ultrasonically treated wastewater to remove large suspended solids and sediments; S3: Adjust the pH value of the screened wastewater and add nutrients to maintain nutritional balance; S4: injecting the adjusted sewage into the biological reaction zone containing pre-cultured aerobic granular sludge, and performing intermittent aeration operation to promote microbial activity and maturation of sludge particles; S5: During the biological reaction process, microwave treatment is performed regularly to enhance the structural stability of sludge particles; S6: chemically precipitating the biologically treated wastewater by adding a predetermined amount of flocculant to remove dissolved phosphorus; S7: Microfiltration of biologically and chemically treated sewage to remove residual sludge particles and fine suspended matter; S8: treating the micro-filtered water with ozone and ultraviolet light to degrade the residual refractory organic matter; S9: Perform terminal disinfection on the treated water to ensure that it meets the discharge standards.

2. The aerobic granular sludge sewage treatment process according to claim 1, characterized in that: The S1 specifically includes: S11: preheating the raw sewage before entering the ultrasonic treatment, adjusting the temperature to 20 to 30 degrees Celsius to optimize the efficiency of the ultrasonic treatment; S12: The preheated sewage is introduced into an ultrasonic reactor, wherein the frequency of the ultrasonic equipment is set at 25kHz to 35kHz, and the power density is controlled at 0.5 to 1.0W / cm 2 ; S13: The duration of ultrasonic treatment is 5 to 15 minutes, ensuring that the macromolecular organic matter in the sewage is fully broken down.

3. The aerobic granular sludge sewage treatment process according to claim 1, characterized in that: The S2 specifically includes: S21: The ultrasonically treated sewage is transported to a preliminary screening station for physical interception using a rotary screen; S22: The mesh size is set to 0.5 to 1.0 mm to capture and remove large suspended solids and sediment-prone solids; 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 directed to the next treatment stage, while the screened solid waste is removed from the screen regularly.

4. The aerobic granular sludge sewage treatment process according to claim 1, characterized in that: The S3 specifically includes: S31: Preliminary determination of the pH value of the filtered wastewater, specifically using an online pH meter for continuous monitoring; S32: If the pH value is lower than 6.5, sodium hydroxide is automatically added for adjustment; if the pH value is higher than 7.5, hydrochloric acid is added for adjustment, and the adjusted target pH value is 6.5 to 7.5; S33: adding nutrients, including a nitrogen source and a phosphorus source, 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 prepared according to the ratio of chemical oxygen demand (COD). The specific ratio of nitrogen and phosphorus added is COD:N=100:5:1, that is, 5 grams of nitrogen and 1 gram of phosphorus are required for every 100 grams of COD.

5. The aerobic granular sludge sewage treatment process according to claim 1, characterized in that: The S4 specifically includes: S41: The sewage with adjusted pH and nutrients is transported to the biological reaction area through a fixed flow rate pump, and the flow rate is set to 1-3m 3 / h; 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; S43: intermittent aeration is used for oxygen supply, and each aeration cycle includes 10 minutes of continuous aeration and 5 minutes of aeration suspension; S44: During aeration, maintain dissolved oxygen concentration between 2 and 4 mg / L to maintain appropriate biological activity; S45: Allow the sludge particles to settle naturally after aeration.

6. The aerobic granular sludge sewage treatment process according to claim 1, characterized in that: The S5 specifically includes: S51: arranging a microwave transmitter in the bioreactor; and setting the frequency of microwave treatment to 2.45 GHz; S52: the duration of each microwave treatment is set to 30 to 90 seconds, and the microwave treatment is performed every 30 to 60 minutes; S53: before each microwave treatment begins, suspending the aeration operation in the biological reaction zone for 3 to 5 minutes; S54: After the microwave treatment is completed, the aeration and stirring operations are restarted.

7. The aerobic granular sludge sewage treatment process according to claim 1, characterized in that: The S6 specifically includes: S61: The biologically treated sewage is introduced into the chemical sedimentation tank, and the flow rate of the sewage is controlled at 2 to 5m 3 / h; S62: When the sewage enters the sedimentation tank, a flocculant is added, and the flocculant is polyferric sulfate or polyaluminium chloride; S63: The amount of flocculant added is controlled between 10 and 50 mg / L; S64: After the flocculant is added, the stirring speed is controlled at 30 to 50 rpm and the stirring is continued for 3 to 5 minutes to ensure that the flocculant is fully mixed with the phosphorus in the sewage to react and form a precipitate; S65: After the stirring is completed, the mixture is allowed to settle for 30 to 60 minutes so that the sediment can fully sink. The supernatant after the sedimentation flows into the subsequent treatment, and the sediment is discharged through the mud outlet for treatment.

8. The aerobic granular sludge sewage treatment process according to claim 1, characterized in that: The S7 specifically includes: S71: The sewage after chemical precipitation treatment is sent to the microfiltration equipment, and the sewage 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 microns; S73: maintaining the filtration pressure at 0.1 to 0.3 MPa during the filtration process; S74: When the microfiltration equipment is in operation, backwashing is performed every 30 minutes, with a backwashing water flow rate of 3 to 5 cubic meters per hour and a duration of 3 to 5 minutes to remove the accumulation on the surface of the microfiltration membrane.

9. The aerobic granular sludge sewage treatment process according to claim 1, characterized in that: The S8 specifically includes: S81: The micro-filtered water is transported to the ozone reactor, and the water flow rate is controlled at 10 to 20 cubic meters per hour to ensure sufficient exposure to ozone; S82: In the ozone reactor, ozone gas is generated by an ozone generator, and the dosage of ozone is controlled at 5 to 10 mg / L, and the dosage time is 5 to 15 minutes to ensure that the ozone fully reacts; S83: After the ozone treatment, the water flows into the ultraviolet light treatment device, and the wavelength of the ultraviolet light irradiation is set to 254nm; S84: During the UV treatment process, the UV intensity is controlled at 30 to 60 mJ / cm 2 , the irradiation time is 5 to 10 minutes.

10. The aerobic granular sludge sewage treatment process according to claim 1, characterized in that: The S9 specifically includes: S91: Introduce the water treated with ozone and ultraviolet light into the disinfection tank, and control the water flow rate at 5 to 10 cubic meters per hour to ensure sufficient disinfection time; S92: Add disinfectant to the disinfection pool. The disinfectant is sodium hypochlorite or chlorine dioxide. The concentration of the disinfectant is controlled at 0.5 to 2 mg / L. S93: After the disinfectant is fully mixed with water, the contact time is maintained for 10 to 30 minutes; S94: After disinfection is completed, measure the residual chlorine concentration in the water and ensure that the residual chlorine concentration is less than 0.5 mg / L before discharge.

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