Sewage treatment method and system based on ozone sludge conditioning

Abstract

The invention discloses a sewage treatment method and system based on ozone sludge conditioning, and the method comprises the following steps: sequentially carrying out activated sludge process treatment and precipitation treatment on sewage to obtain purified water and activated sludge; at least part of the activated sludge is subjected to ozone conditioning treatment, and a cracking product is obtained; the cracking product is used as a raw material for activated sludge process treatment; the ozone conditioning treatment comprises at least one time of contact treatment of the activated sludge and ozone in an environment with a magnetic field intensity of 5000-7000 Gs and a pressure of 0.5-0.7 MPa. The sewage treatment method based on ozone sludge conditioning provided by the invention has the characteristics of high ozone utilization rate and good sludge reduction effect.

Description

Technical Field

[0001] The invention relates to the field of environmental engineering, and in particular to a sewage treatment method and system based on ozone sludge conditioning. Background Art

[0002] At present, ozone can be used to condition activated sludge during sewage treatment. During the conditioning process, ozone attacks the proteins and other components on the surface of the sludge cell membrane, causing the cells to rupture and the organic matter to dissolve, converting part of the organic matter in the sludge into soluble substances that can be biodegraded. After returning to the biological reactor, it can be used as a carbon source by microorganisms, which can make up for the problem of insufficient organic carbon sources in sewage treatment plants and reduce the output of residual sludge, achieving the purpose of in-situ sludge reduction.

[0003] At present, the use of ozone to condition activated sludge has the following defects: low ozone utilization rate, insufficient reaction with sludge, poor sludge reduction effect and high reduction cost.

[0004] Therefore, developing a sludge conditioning method with high ozone utilization rate and better sludge reduction effect has become a research direction. Summary of the invention

[0005] The present invention provides a sewage treatment method based on ozone sludge conditioning, which has the characteristics of high ozone utilization rate and good sludge reduction effect.

[0006] The invention also provides a sewage treatment system, which has the characteristic of low sludge output.

[0007] The present invention provides a sewage treatment method based on ozone sludge conditioning, which includes sequentially subjecting sewage to activated sludge treatment and sedimentation treatment to obtain purified water and activated sludge;

[0008] ozone conditioning treatment is performed on at least a portion of the activated sludge to obtain a pyrolysis product; the pyrolysis product is used as a raw material for the activated sludge process;

[0009] The ozone conditioning treatment includes subjecting the activated sludge to at least one contact treatment with ozone in an environment with a magnetic field strength of 5000-7000 Gs and a pressure of 0.5-0.7 MPa.

[0010] In the above-mentioned wastewater treatment method based on ozone sludge conditioning, the total contact time of the contact treatment is 15-30 min.

[0011] As described above, in the wastewater treatment method based on ozone sludge conditioning, in the contact treatment, the total dosage of ozone is 15-35 mg ozone per gram SS.

[0012] As described above, in the wastewater treatment method based on ozone sludge conditioning, the activated sludge is contacted with the ozone for m times, m>1, and the amount of ozone added decreases gradually during the contact treatments from the first to the mth times.

[0013] As described above, the wastewater treatment method based on ozone sludge conditioning, wherein the activated sludge process treatment includes anaerobic treatment, anoxic treatment, and aerobic treatment performed in sequence, and the pyrolysis product is used as a raw material for the anoxic treatment.

[0014] The wastewater treatment method based on ozone sludge conditioning as described above, wherein, it also includes using the residual gas including ozone obtained from the contact treatment to contact the rest of the activated sludge.

[0015] The present invention also provides a sewage treatment system, which is used to perform any of the above-mentioned sewage treatment methods based on ozone sludge conditioning. The system includes an activated sludge treatment unit, a sedimentation unit, a contact unit, and an ozone generation unit;

[0016] The outlet of the activated sludge process treatment unit is connected to the inlet of the sedimentation unit;

[0017] The sludge return outlet of the sedimentation unit is connected to the inlet of the contact unit;

[0018] The lysate outlet of the contact unit is connected to the lysate inlet of the activated sludge process treatment unit;

[0019] The contact unit comprises a contact reactor, the inner wall of the contact reactor comprises a magnet, and the interior of the contact reactor is divided into n+1 chambers by n hollow partition walls with through holes, where n≥0;

[0020] The n hollow partition walls with through holes are respectively connected to the n ozone inlets arranged on the outer wall of the contact reactor, and the n ozone inlets are respectively connected to the ozone outlets of the ozone generating units.

[0021] The sewage treatment system as described above, wherein n=3, and the ozone flow ratio of the three ozone inlets arranged on the outer wall of the contact reactor is 5:3:2.

[0022] The sewage treatment system as described above, wherein the activated sludge treatment unit comprises an anaerobic tank, an anoxic tank, and an aerobic tank connected in sequence, the lysate outlet of the contact unit is connected to the lysate inlet of the anoxic tank; the sedimentation unit comprises a secondary sedimentation tank; and the ozone generating unit comprises an ozone generator.

[0023] The sewage treatment system as described above, wherein, also includes a sludge dewatering unit, the sludge dewatering unit includes a sludge dewatering room; the sludge dewatering outlet of the sedimentation unit is connected to the inlet of the sludge dewatering unit; also includes a primary sedimentation unit, the primary sedimentation unit includes a primary sedimentation tank; the outlet of the primary sedimentation unit is connected to the inlet of the activated sludge treatment unit.

[0024] The sewage treatment method based on ozone sludge conditioning provided by the present invention allows ozone to contact with activated sludge in a magnetic field and a pressurized environment, thereby improving the solubility of ozone in liquid, and has the characteristics of high ozone utilization rate and good sludge reduction effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced one by one below. Obviously, the drawings in the following description are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0026] Figure 1 A schematic diagram of a first sewage treatment system provided by the present invention;

[0027] Figure 2 is a structural diagram of a contact reactor;

[0028] Figure 3 A device diagram of a second sewage treatment system provided by the present invention;

[0029] Figure 4 A device diagram of a third sewage treatment system provided by the present invention;

[0030] Figure 5 The changes in the sludge concentration in the aerobic tank of the embodiment and the comparative example;

[0031] Figure 6 The COD changes of the inlet and outlet water of the sewage treatment system of the embodiment and the comparative example;

[0032] Figure 7 The total nitrogen changes in the inlet and outlet water of the sewage treatment system of the embodiment and the comparative example;

[0033] Figure 8 The changes of ammonia nitrogen in the inlet and outlet water of the sewage treatment system of the embodiment and the comparative example;

[0034] Fig. 9 The figure shows the changes of total phosphorus in the inlet and outlet water of the sewage treatment system of the embodiment and the comparative example.

[0035] Description of reference numerals:

[0036] 100-Activated sludge treatment unit;

[0037] 200-precipitation unit;

[0038] 300-contact unit;

[0039] 400-Ozone generating unit;

[0040] 500-sludge dewatering unit;

[0041] 1001-Anaerobic tank;

[0042] 1002-Anoxic pool;

[0043] 1003-Aerobic pool;

[0044] 2001-Secondary sedimentation tank;

[0045] 3001-contact reactor;

[0046] 4001-Ozone generator;

[0047] 5001-Sludge dewatering room;

[0048] 6001-primary sedimentation tank;

[0049] 3001A-magnet;

[0050] 3001B-Hollow partition wall;

[0051] 3001C-Ozone inlet;

[0052] 3001D-sludge inlet;

[0053] 3001E-lysate outlet;

[0054] 3001F - Gas outlet. DETAILED DESCRIPTION

[0055] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below. The specific implementation methods listed below are only for describing the principles and features of the present invention. The examples are only used to explain the present invention and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0056] At present, in the sewage treatment process, the use of ozone to condition activated sludge has the disadvantages of low ozone utilization rate, insufficient reaction degree with sludge, poor sludge reduction effect and high reduction cost. The reason is that ozone has low solubility in sludge, resulting in low utilization rate, insufficient reaction degree with sludge, poor sludge reduction effect and high reduction cost. Studies have found that in an environment with a certain intensity of magnetic field and a certain pressure, the solubility of ozone in sludge is significantly improved.

[0057] Based on this, the first aspect of the present invention provides a sewage treatment method based on ozone sludge conditioning, the method comprising sequentially subjecting the sewage to an activated sludge process and a sedimentation process to obtain purified water and activated sludge;

[0058] ozone conditioning treatment is performed on at least a portion of the activated sludge to obtain a pyrolysis product; the pyrolysis product is used as a raw material for the activated sludge process;

[0059] The ozone conditioning treatment includes subjecting the activated sludge to at least one contact treatment with ozone in an environment with a magnetic field strength of 5000-7000 Gs and a pressure of 0.5-0.7 MPa.

[0060] The sewage treatment method based on ozone sludge conditioning provided by the present invention can treat sewage through activated sludge treatment and sedimentation treatment to obtain activated sludge including microorganisms while obtaining purified water. The present invention does not limit the specific process of the activated sludge method, and can use the activated sludge process commonly used in the art. For example, the activated sludge method treatment can be selected from any one of the traditional activated sludge method, the anaerobic-anoxic-aerobic activated sludge method, and the anaerobic-aerobic activated sludge method. The sedimentation treatment is to separate the purified water from the activated sludge by standing the mixture including purified water and activated sludge obtained by the activated sludge method.

[0061] At least part of the sludge obtained by the sedimentation treatment is subjected to ozone conditioning treatment to obtain a pyrolysis product. During the ozone conditioning treatment, ozone conditions the activated sludge. During the ozone conditioning process, ozone attacks components such as proteins on the surface of the sludge cell membrane, causing the cells to rupture and organic matter to dissolve, and converts part of the organic matter in the sludge into soluble substances that can be biodegraded. The pyrolysis product obtained can be used as a carbon source and other raw materials for the activated sludge process.

[0062] Among them, the ozone conditioning treatment includes subjecting the activated sludge to at least one contact treatment with ozone in an environment with a magnetic field strength of 5000-7000 Gs and a pressure of 0.5-0.7MPa, wherein the contact treatment refers to the process of contacting ozone or a gas including ozone with the activated sludge so that the ozone converts at least part of the activated sludge into pyrolysis products. Conducting at least one contact treatment means that the activated sludge can be contacted with ozone once or multiple times, for example, three times. Contacting the activated sludge with ozone multiple times can increase the pyrolysis rate of the activated sludge and improve the sludge reduction effect of the sewage treatment method provided by the present invention.

[0063] Research has found that the current use of ozone to condition activated sludge in sewage treatment has the disadvantages of low ozone utilization, insufficient reaction with sludge, poor sludge reduction effect, and high reduction cost. The reason is that ozone has low solubility in sludge, resulting in low utilization, insufficient reaction with sludge, and poor sludge reduction effect. In response to the above defects, research has found that in an environment with a certain intensity of magnetic field and a certain pressure, the solubility of ozone in sludge is significantly improved, so that the sewage treatment method provided by the present invention has the technical effect of high ozone utilization and good sludge reduction effect.

[0064] In order to make the sewage treatment method provided by the present invention have a better sludge reduction effect and further improve the ozone utilization rate, the total contact time of the contact treatment can be controlled to be 15-30 min, and the total dosage of ozone is 15-35 mg / g SS. The total contact time refers to the sum of the time of each contact treatment in at least one contact treatment; the total dosage of ozone refers to the total amount of ozone consumed in each contact treatment. The total dosage of ozone is calculated based on the mass of SS (suspended solids) in the activated sludge, and 15-35 mg of ozone is added per gram of SS. Appropriate contact time and ozone dosage can make ozone and activated sludge fully react, so that the sewage treatment method provided by the present invention has a better sludge reduction effect and a higher ozone utilization rate.

[0065] In order to further improve the utilization rate of ozone, in a specific embodiment, the activated sludge can be contacted with the ozone for m times, m>1, wherein the amount of ozone added decreases gradually from the first to the mth contact treatment. Specifically, the activated sludge can be contacted with ozone for 3 times, wherein the amount of ozone added decreases gradually from the first to the third contact treatment. For example, in the first contact treatment, the total amount of ozone added is 15 mg / g SS; in the second contact treatment, the total amount of ozone added is 10 mg / g SS; in the third contact treatment, the total amount of ozone added is 5 mg / g SS. Of course, the activated sludge can also be contacted with ozone for 5 times, and the amount of ozone added decreases gradually from the first to the fifth contact treatment, and so on. In the first contact treatment, the concentration of activated sludge is the highest, so the amount of ozone added is also the highest; as the contact treatment proceeds, the concentration of activated sludge decreases, and thus the amount of ozone added decreases accordingly. Multiple contact treatments with stepped concentrations can prolong the contact time between ozone and activated sludge, further enhance the solubility of ozone in the sludge solution, and improve the reaction efficiency and ozone utilization rate.

[0066] In a specific embodiment, the activated sludge process includes anaerobic treatment, anoxic treatment, and aerobic treatment performed in sequence, and the pyrolysis product is used as a raw material for anoxic treatment. The anaerobic treatment, anoxic treatment, and aerobic treatment performed in sequence are AAO treatment, which has a good effect of removing nitrogen and phosphorus while achieving a good BOD removal effect. When the pyrolysis product is used in anoxic treatment, the denitrification activity of microorganisms in the anoxic treatment can be improved, so that the sewage treatment method provided by the present invention has a better denitrification effect.

[0067] In another embodiment, the sewage is further subjected to a pre-sedimentation treatment before being subjected to the activated sludge process. The pre-sedimentation treatment can remove part of the SS contained in the sewage and reduce the subsequent treatment load.

[0068] To further reduce the cost of sludge treatment, 10%-20% of the total amount of activated sludge can be used for ozone conditioning. In addition, 10-30% of the total amount of sludge in the biochemical treatment section of the sewage plant (for example, the biochemical treatment section includes anaerobic zone, anoxic zone and aerobic zone) can also be used for ozone conditioning. Since the carbon source required for activated sludge treatment is limited, using part of the activated sludge for ozone conditioning can not only provide the carbon source required for activated sludge treatment, but also save ozone consumption, which can further reduce treatment costs.

[0069] In order to further improve the sludge reduction effect of the sewage treatment method provided by the present invention, in one embodiment, it also includes contacting the remaining activated sludge with the remaining gas containing ozone obtained by the contact treatment. When the gas containing ozone is used to contact the part of the activated sludge, part of the ozone often remains in the remaining gas. This part of the ozone contacts the remaining activated sludge that has not been subjected to the aforementioned contact treatment to further achieve the purpose of sludge reduction.

[0070] For example, within a certain period of time, the output of activated sludge is 10m³. Take 3m³ of it and contact it with ozone to obtain cracking products and residual gas; the residual gas can be brought into contact with the remaining 7m³ of activated sludge to enhance the sludge dewatering performance and further achieve the purpose of sludge reduction.

[0071] The second aspect of the present invention provides a sewage treatment system, which is used to implement the sewage treatment method based on ozone sludge conditioning provided in the first aspect of the present invention. The system specifically includes an activated sludge treatment unit, a sedimentation unit, a contact unit, and an ozone generation unit;

[0072] The outlet of the activated sludge process treatment unit is connected to the inlet of the sedimentation unit;

[0073] The sludge return outlet of the sedimentation unit is connected to the inlet of the contact unit;

[0074] The lysate outlet of the contact unit is connected to the lysate inlet of the activated sludge process treatment unit;

[0075] The contact unit comprises a contact reactor, the inner wall of which is provided with a magnet, and the interior of the contact reactor is divided into n+1 chambers by n hollow partition walls with through holes, where n≥0;

[0076] The n hollow partition walls with through-holes are respectively connected to the n ozone inlets arranged on the outer wall of the contact reactor, and the n ozone inlets are respectively connected to the ozone outlets of the ozone generating units.

[0077] Figure 1 The first sewage treatment system provided by the present invention is shown in FIG. Figure 1 As shown, the system includes 100-activated sludge treatment unit, 200-precipitation unit, 300-contact unit, 400-ozone generating unit; the outlet of 100-activated sludge treatment unit is connected with the inlet of 200-precipitation unit; the sludge return outlet of 200-precipitation unit is connected with the inlet of 300-contact unit; the lysate outlet of 300-contact unit is connected with the lysate inlet of 100-activated sludge treatment unit.

[0078] 100-Activated sludge treatment unit is used to perform activated sludge treatment. The present invention does not limit the specific structures included in the unit, for example, it can include an aeration tank. 200-Sedimentation unit is used to perform sedimentation treatment, for example, it can include a secondary sedimentation tank. 400-Ozone generation unit is used to generate ozone, for example, it can include an ozone generator.

[0079] 300-Contact unit includes 3001-contact reactor. Figure 2 It is a structural diagram of a 3001-contact reactor, such as Figure 2 As shown, the inner wall of the contact reactor 3001 includes a magnet 3001A (which may be a permanent magnet or an electromagnet), and the interior of the contact reactor 3001 is divided into four chambers by three hollow partition walls 3001B having through holes. The cavity inside each hollow partition wall 3001B is respectively connected to the ozone inlet 3001C of the contact reactor 3001, and each ozone inlet 3001C is respectively connected to the ozone outlet 400 of the ozone generating unit.

[0080] When the 3001-contact reactor is in operation, the activated sludge enters from the 3001D-sludge inlet at the left end, moves from left to right in the chamber of the contact reactor, passes through the 3001B-hollow partition wall with through holes on three sides in turn, and leaves the contact reactor from the 3001E-lysate outlet at the right end. At the same time, the 3001B-hollow partition wall receives ozone provided by the 400-ozone generating unit, and the activated sludge near the partition wall is aerated, so that the ozone and the activated sludge are contacted and treated, and the activated sludge is converted into lysate. At the same time, the 3001A-magnet (which can be a permanent magnet or an electromagnet) on the inner wall of the contact reactor provides a magnetic field, and the ozone provided by the 400-ozone generating unit provides the pressure required for the reaction through aeration. After the contact treatment, the remaining gas including ozone leaves the 3001-contact reactor through the 3001F-gas outlet.

[0081] Understandably, Figure 2 This is only one structure of the 3001-contact reactor. The 3001-contact reactor may have multiple hollow partition walls, which may be arranged as required.

[0082] The sewage treatment system provided by the present invention realizes contact reaction between ozone and activated sludge under a magnetic field and a certain pressure through a contact reactor with a specific structure, and has the characteristic of low sludge output.

[0083] Further, in one embodiment, n=3, and the ozone flow ratio in the three 3001C-ozone inlets provided on the outer wall of the 3001-contact reactor is 5:3:2. Multiple contact treatments with stepped concentrations can extend the contact time between ozone and activated sludge, further enhance the solubility of ozone in the sludge solution, and improve the reaction efficiency and ozone utilization rate.

[0084] In one embodiment, in the sewage treatment system provided by the present invention, the activated sludge treatment unit includes an anaerobic tank, an anoxic tank, and an aerobic tank connected in sequence, and the lysate outlet of the contact unit is connected to the lysate inlet of the anoxic tank; the sedimentation unit includes a secondary sedimentation tank; and the ozone generation unit includes an ozone generator.

[0085] Figure 3 This is a diagram of the second sewage treatment system provided by the present invention. Figure 3 As shown, the system may also include a 500-sludge dewatering unit, which includes a sludge dewatering room. The sludge dewatering outlet of the 200-sedimentation unit is connected to the inlet of the 500-sludge dewatering unit; in addition, it also includes a 600-primary sedimentation unit, which includes a primary sedimentation tank; the outlet of the 600-primary sedimentation unit is connected to the inlet of the 100-activated sludge treatment unit.

[0086] Figure 4 The device diagram of the third sewage treatment system provided by the present invention is as follows: Figure 4 As shown, the system includes 1001-anaerobic tank, 1002-anoxic tank, 1003-aerobic tank, 2001-secondary sedimentation tank, 3001-contact reactor, 4001-ozone generator, 5001-sludge dewatering machine room, and 6001-primary sedimentation tank. Among them, 6001-primary sedimentation tank, 1001-anaerobic tank, 1002-anoxic tank, 1003-aerobic tank, 2001-secondary sedimentation tank, and 5001-sludge dewatering machine room are connected in sequence, the sludge return outlet of 2001-secondary sedimentation tank is connected to the inlet of 3001-contact reactor, the lysate outlet of 3001-contact reactor is connected to the lysate inlet of 1002-anoxic tank, the gas outlet of 3001-contact reactor is connected to 5001-sludge dewatering machine room, and the ozone outlet of 4001-ozone generator is connected to the ozone inlet of 3001-contact reactor.

[0087] Understandably, Figure 4 The sewage treatment system shown also includes an internal return system and an external return system. The internal return system returns the water at the end of the aerobic tank 1003 to the anoxic tank 1002, and the external return system returns the sludge at the bottom of the secondary sedimentation tank 2001 to the anaerobic tank 1001. 2 O treatment process is commonly used, so in Figure 4 Not shown.

[0088] When the pyrolysis product is used for anoxic treatment, the denitrification activity of microorganisms in the anoxic treatment can be improved, so that the sewage treatment method provided by the present invention has a better denitrification effect; when a part of the activated sludge is contacted with a gas including ozone, part of the ozone often remains in the remaining gas. This part of the ozone can be contacted with the remaining activated sludge in the 5001-sludge dewatering room that has not been subjected to the aforementioned contact treatment, so as to further achieve the purpose of sludge reduction.

[0089] Example:

[0090] This embodiment uses Figure 4 The sewage treatment system shown in the figure treats sewage. The biochemical treatment section of the system consists of 1001-anaerobic tank, 1002-anoxic tank, and 1003-aerobic tank. The hydraulic retention time of sewage in the biochemical treatment section is 10h. The sewage comes from the influent (domestic sewage) of the Hexi Water Purification Plant in Lu'an City, Anhui Province, and the influent flow rate is 50 m 3 / d, the sludge concentration of 1003-aerobic tank is 4700~5500 mg / L, the external reflow ratio is 100%, and the internal reflow ratio is 300%. Among them, the external reflow ratio is the ratio of the flow rate of sludge from 2001-secondary sedimentation tank to 1001-anaerobic tank to the influent flow rate of sewage treatment system, and the internal reflow ratio is the ratio of the flow rate of 1003-aerobic tank end to 1002-anoxic tank to the influent flow rate of sewage treatment system.

[0091] 4001-Ozone generator is composed of air compressor, oxygen generator, air source ozone generator, etc. The concentration of ozone produced is 100~200 mg / L, and the maximum output is 2 kg / h.

[0092] The 3001-contact reactor is a permanent magnet with a volume of 200 L (a horizontal cylinder with a length of 2 m and a diameter of 0.36 m). The interior is evenly divided into four chambers by three hollow partitions with through-holes. The 3001B-hollow partition is equipped with an ozone inlet pipe. According to the digital Gauss meter test, the magnetic field strength inside the 3001-contact reactor is in the range of 6000~6500 Gs.

[0093] During ozone conditioning, the 3001-contact reactor is fed with sludge from the 2001-secondary sedimentation tank, and the sludge flow rate is 0.5 m 3 / h, which is about 25% of the external return flow rate. At this time, the sludge external return flow rate is about 1.5 m 3 / h, the residence time of sludge in the 3001-contact reactor is about 25 min, and the pressure in the 3001-contact reactor is 0.6 Mpa. The ozone concentration produced by the 4001-ozone generator is 150 mg / L, and the three hollow partitions in the 3001-contact reactor are aerated at flow rates of 10 L / min, 6 L / min and 4 L / min respectively. During the operation of the 3001-contact reactor, the 4001-ozone generator is operated intermittently, and it is turned off for 10 minutes after running for 10 minutes, and the cycle is repeated until it stops. The 3001-contact reactor is divided into two time periods for operation in the morning and afternoon. Each operation time is about 3 hours, and the daily operation time is about 6 hours. The 4001-ozone generator produces a total of about 540 g of ozone per day, and the total amount of sludge treated is about 3m 3 , accounting for about 15% of the total sludge volume in the biochemical treatment section (1001-anaerobic tank, 1002-anoxic tank, 1003-aerobic tank), and the ozone dosage is about 35 mg / g·SS (calculated based on the sludge concentration of 5100 mg / L).

[0094] The sewage treatment system has been in operation for more than 3 months. The effluent indicators are stable during the operation. 500 L of sludge is discharged from the 2001-secondary sedimentation tank every day, and the sludge age is about 42 days. During this period, the sludge concentration in the 1003-aerobic tank has been maintained at 4700~5500 mg / L, with an average value of 5140 mg / L.

[0095] Comparative Example:

[0096] This comparative example uses Figure 4 The sewage treatment system shown in the figure treats sewage. The biochemical treatment section consists of 1001-anaerobic tank, 1002-anoxic tank, and 1003-aerobic tank. The hydraulic retention time of sewage in the biochemical treatment section is 10 h. The reactor inlet is the inlet water (domestic sewage) of the Hexi Water Quality Evolution Plant in Lu'an City, Anhui Province, and the inlet flow rate is 50 m 3 / d, the sludge concentration in the aerobic tank is 4700~5500 mg / L, the external reflow ratio is 100%, and the internal reflow ratio is 300%.

[0097] 4001-Ozone generator is composed of air compressor, oxygen generator, air source ozone generator, etc. The concentration of ozone produced is 100~200 mg / L, and the maximum output is 2 kg / h.

[0098] The 3001-contact reactor is a permanent magnet with a volume of 200 L (a horizontal cylinder with a length of 2m and a diameter of 0.36m). The interior is evenly divided into four chambers by three 3001B-hollow partitions with through holes. The hollow partitions are equipped with ozone inlet pipes. According to the digital Gauss meter test, the magnetic field strength inside the 3001-contact reactor is in the range of 6000~6500 Gs.

[0099] During the operation of the equipment, the mud flow rate of the 3001-contact reactor was 0.5 m 3 / h, which is about 25% of the external return flow rate. At this time, the sludge external return flow rate is about 1.5 m 3 / h, the residence time of sludge in the 3001-contact reactor is about 25 min, and the pressure in the 3001-contact reactor is 0.6 Mpa. The 4001-ozone generator only turns on the air compressor without producing ozone, and aerates the three hollow partitions in the reactor at flow rates of 10 L / min, 6 L / min and 4 L / min respectively. The 3001-contact reactor is divided into two time periods for operation in the morning and afternoon, each time for about 3 hours, and the daily operation time is about 6 hours. The total amount of sludge treated is about 3 m 3 , accounting for about 15% of the total sludge volume in the biochemical treatment section (1001-anaerobic tank, 1002-anoxic tank, 1003-aerobic tank), and the ozone dosage is 0 mg / g·SS (calculated based on the sludge concentration of 5100 mg / L).

[0100] The sewage treatment system was in continuous operation for more than 3 months. The effluent indicators were stable during the operation. 1000 L of sludge was discharged from the 2001-secondary sedimentation tank every day, and the sludge age was about 21 days. During this period, the sludge concentration in the 1003-aerobic tank remained at 4700~5500 mg / L, with an average value of 5012 mg / L.

[0101] During the operation, the changes in the sludge concentration of the 1003-aerobic pool, the COD of the influent and effluent, the total nitrogen, ammonia nitrogen, and the total phosphorus of the embodiment and the comparative example are shown in Figures 5 to 9 .

[0102] The reactors in the embodiments and comparative examples were not dosed with phosphorus removal agents such as PAC, and thus the total phosphorus removal effect in the sewage was poor.

[0103] From the above content, it can be seen that compared with the comparative example, the amount of sludge discharged from the 2001-second sedimentation tank per day in the embodiment is greatly reduced, indicating that the sewage treatment method based on ozone sludge conditioning provided by the present invention has the characteristics of high ozone utilization rate and good sludge reduction effect.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention.

Claims

1. A sewage treatment method based on ozone sludge conditioning, characterized in that: The sewage is sequentially treated by activated sludge method and sedimentation to obtain purified water and activated sludge; ozone conditioning treatment is performed on at least a portion of the activated sludge to obtain a pyrolysis product; the pyrolysis product is used as a raw material for the activated sludge process; The ozone conditioning treatment includes subjecting the activated sludge to at least one contact treatment with ozone in an environment with a magnetic field strength of 5000-7000 Gs and a pressure of 0.5-0.7 MPa.

2. The sewage treatment method based on ozone sludge conditioning according to claim 1, characterized in that: The total contact time of the contact treatment is 15-30 min.

3. The sewage treatment method based on ozone sludge conditioning according to claim 2 is characterized in that: In the contact treatment, the total dosage of ozone is 15-35 mg of ozone per gram of SS.

4. The sewage treatment method based on ozone sludge conditioning according to claim 1, characterized in that: The activated sludge is contacted with the ozone for m times, where m>1, and the amount of ozone added decreases gradually during the contact treatments from the first to the mth time.

5. The method for treating sewage based on ozone sludge conditioning according to claim 1, characterized in that: The activated sludge process includes anaerobic treatment, anoxic treatment and aerobic treatment performed in sequence, and the pyrolysis product is used as a raw material for the anoxic treatment.

6. The method for treating sewage based on ozone sludge conditioning according to any one of claims 1 to 5, characterized in that: The method also includes using the remaining gas including ozone obtained from the contact treatment to contact the remaining activated sludge.

7. A sewage treatment system for executing the sewage treatment method based on ozone sludge conditioning according to any one of claims 1 to 6, characterized in that: It includes activated sludge treatment unit, sedimentation unit, contact unit and ozone generation unit; The outlet of the activated sludge process treatment unit is connected to the inlet of the sedimentation unit; The sludge return outlet of the sedimentation unit is connected to the inlet of the contact unit; The lysate outlet of the contact unit is connected to the lysate inlet of the activated sludge process treatment unit; The contact unit comprises a contact reactor, the inner wall of the contact reactor comprises a magnet, and the interior of the contact reactor is divided into n+1 chambers by n hollow partition walls with through holes, where n≥0; The n hollow partition walls with through holes are respectively connected to the n ozone inlets arranged on the outer wall of the contact reactor, and the n ozone inlets are respectively connected to the ozone outlets of the ozone generating units.

8. The sewage treatment system according to claim 7, characterized in that: n=3, and the ozone flow ratio of the three ozone inlets arranged on the outer wall of the contact reactor is 5:3:

2.

9. The sewage treatment system according to claim 7, characterized in that: The activated sludge treatment unit comprises an anaerobic tank, an anoxic tank and an aerobic tank which are connected in sequence, and the lysate outlet of the contact unit is connected with the lysate inlet of the anoxic tank; the sedimentation unit comprises a secondary sedimentation tank; and the ozone generation unit comprises an ozone generator.

10. The sewage treatment system according to any one of claims 7 to 9, characterized in that: It also includes a sludge dewatering unit, which includes a sludge dewatering room; the sludge dewatering outlet of the sedimentation unit is connected to the inlet of the sludge dewatering unit; it also includes a primary sedimentation unit, which includes a primary sedimentation tank; the outlet of the primary sedimentation unit is connected to the inlet of the activated sludge treatment unit.

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