Device and method for reducing pressure drop of return sludge sorting unit of biochemical pool

Abstract

The invention relates to a device and a method for reducing the pressure drop of a return sludge sorting unit of a biochemical pool, and provides a device for reducing the pressure drop of the return sludge sorting unit of the biochemical pool, which comprises an inlet manifold connected with the inlet of each rotational flow core tube of the device; the underflow collecting pipe is connected with the underflow ports of the rotational flow core pipes; the inlet manifold is connected with the cyclone core pipes, the overflow manifold is connected with the overflow ports of the cyclone core pipes, the ratio of the distance between the cyclone core pipes to the nominal diameter of the cyclone core pipes is 1-4, the dip angle of each cyclone core pipe is 0-20 degrees, and the dip angle of the inlet manifold is 5-15 degrees. The invention also provides a method for reducing the pressure drop of the return sludge sorting unit of the biochemical pool by using the device. According to the invention, the minimization of sorting pressure drop and feeding balance between the biochemical return sludge sorting hydrocyclones are realized, so that the sewage enhanced biochemical treatment energy consumption is improved.

Description

Technical Field

[0001] The present application belongs to the field of sewage biochemical enhanced operation, and provides a device and method for reducing the pressure drop in a sludge sorting process, and specifically relates to a device and method for reducing the pressure drop in a biochemical pool return sludge sorting unit. Background Art

[0002] The activated sludge process is widely used in municipal and industrial sewage treatment plants due to its high degradation efficiency and low treatment cost. With the annual increase in the total amount of industrial and domestic sewage discharge, existing sewage treatment plants generally have the problem of insufficient load; coupled with the continuous improvement of regional sewage discharge standards, sewage capacity expansion and standard improvement are still major issues that need to be urgently addressed in the current environmental protection field. The biochemical return sludge cyclone separation process has a significant effect of biochemical standard expansion by improving sludge settling properties and improving sludge load; however, in order to take into account the economic requirements of the biochemical enhancement process, it is necessary to propose practical strategies for the economic optimization of the biochemical enhancement process.

[0003] In response to problems such as reduced load capacity of sewage treatment plants, reduced sludge settling performance, and increased energy consumption in sewage treatment, scholars and engineers at home and abroad have conducted extensive technical exploration.

[0004] Chinese patent ZL202010048132.7 discloses a sludge cyclone sorting and activation treatment method and device, which adopts a cyclone treatment method to achieve directional sorting and sludge discharge, improves the sludge settling, dewatering and activity, improves the degradation efficiency of the biochemical pool, and reduces the residual sludge output.

[0005] Chinese patent application CN116239257A discloses a fully modular sewage treatment device, which is based on the AAO (anaerobic anoxic aerobic) + AO (anaerobic aerobic) process and coupled with sludge cyclone sorting equipment. Without increasing the energy consumption of the system, the degradation efficiency of the biochemical pool is improved and the sludge settling performance is improved, which plays a vital role in the stable operation of the biochemical pool. However, the device has problems such as large footprint and increased treatment costs.

[0006] Chinese patent ZL202322147275.5 discloses a sludge cyclone sorting, quality improvement and activation treatment device, which is fully automatically operated after being connected to the domestic sewage, industrial sewage and difficult-to-degrade sewage microbial treatment system, and sorts the sludge produced and discharged by the above-mentioned sewage biochemical system, sorts out high-activity and low-activity component sludge, and returns the high-activity component sludge to the above-mentioned sewage biochemical system, which can ensure the sludge activity in the sewage biochemical system and achieve the activated sludge in a high-quality stage for a long time, thereby making the activated sludge method The ability to treat sewage is more stable, and the effluent is stable and meets the standards for a long time.

[0007] Chinese Patent ZL202311323054.7 discloses a method for grading and discharging sludge of a sewage treatment system, which can perform differential sorting on activated sludge, discharge sludge rich in inorganic matter and sludge with poor sedimentation performance from the system, and retain sludge loaded with organic matter and sludge with good sedimentation performance in the system, thereby improving the sewage treatment efficiency.

[0008] Chinese Patent Application CN115572014A discloses a method and system for online strengthening treatment of refractory sewage by microorganisms. The system includes an activated sludge sorting device, which is arranged between the biofilm-activated sludge hybrid biochemical pool and the sedimentation tank. The use of this device successfully achieves the goal of separating low-activity and inactivated sludge from the biofilm-activated sludge hybrid biochemical pool system as surplus sludge for discharge, and overall improves the sludge load of the activated sludge in the biofilm-activated sludge hybrid biochemical pool.

[0009] Chinese Patent ZL201921766864.9 discloses a sludge sorting and treatment device. The fixed plate in this device can convey sludge from the lower end of the conveyor belt to the upper end, so that all sludge can be sorted, reducing the remaining sludge. And the filter plate is composed of filter meshes with different mesh sizes, which helps to improve the fineness of sorting; however, this device only provides a method for sorting surplus sludge and is not applicable to the sorting of sludge in the secondary sedimentation tank effluent to strengthen the sewage biochemical process.

[0010] Chinese Patent CN202036825U discloses an activated sludge method high sedimentation performance sludge sorting device, which directly discharges surplus sludge from the sludge storage area of the sludge sorting device, ensuring that the sorted activated sludge with poor sedimentation performance can be discharged from the system in time and no longer enter the system, thereby improving the sedimentation performance of sludge in the activated sludge treatment process and forming a high-concentration activated sludge mixed liquor.

[0011] Chinese Patent ZL201720275974.X discloses a sludge sorting and treatment device. This device selectively collects sludge using the main sieve mesh, separates sludge according to particle size; uses the collection function after the separation of water and sludge by the main sieve mesh, and the water collecting plate and water collecting tank collect water to form an internal water cycle in the water path, realizing the recycling of water and saving water resources. Using this device to sort sludge has a simple process, a large treatment capacity, a high separation efficiency, and broad application prospects.

[0012] Chinese Patent Application CN117658309A discloses an activated sludge sorting method and a sewage treatment method. This method can monitor the situation of sorting activated sludge in real time according to the organic matter content in the activated sludge, thereby being able to increase the organic matter content of the activated sludge in the biochemical pool and improve the treatment effect of the activated sludge method.

[0013] The above-mentioned existing methods and devices widely propose methods for implementing cyclone separation on the return sludge of different biochemical processes to improve the sludge settling property and activity, thereby improving the degradation efficiency of the biochemical system, inhibiting sludge bulking, and controlling the discharge amount of excess sludge. However, the specific flow structure designed for the cyclone separation equipment to achieve the separation effect has certain pressure losses. Integrating the cyclone separation of the return sludge in the conventional biochemical process will cause certain energy consumption. In special cases such as renovation and expansion, when using the existing sludge return pump, there may also be problems such as insufficient head of the existing pump. At the same time, in the integrated equipment designed by parallel amplification, there may also be problems such as poor uniformity between single cyclones and inability to meet the overall operation efficiency.

[0014] Therefore, there is an urgent need in the art to develop a low-consumption and high-efficiency separation device and method for biochemical return sludge that properly controls the process conditions of the separation method and the equipment layout to strengthen the biochemical treatment of sewage. Summary of the Invention

[0015] The present application provides a novel low-consumption sludge separation device and method, which improves the sludge settling performance by using the cyclone separation method and reduces the treatment energy consumption through the reasonable layout of each pipeline, thereby solving the problems existing in the prior art.

[0016] On the one hand, the present disclosure provides a device for reducing the pressure drop of the separation unit of the return sludge in the biochemical tank. The device includes: An inlet header connected to the inlets of each cyclone core tube of the device. Among them, the return sludge enters each cyclone core tube distributed on the left and right sides of the inlet header evenly through the inlet header; A bottom flow header connected to the underflow ports of each cyclone core tube, which is used to discharge the underflow of the return sludge processed by the cyclone core tube to the front end of the biochemical tank; and An overflow header connected to the overflow ports of each cyclone core tube, which is used to discharge the overflow of the return sludge processed by the cyclone core tube as excess sludge. Among them, the ratio of the distance between each cyclone core tube to the nominal diameter of the cyclone core tube is 1-4, the inclination angle of each cyclone core tube is 0-20°, and the inclination angle of the inlet header is 5°-15°.

[0017] In a preferred embodiment, the cyclone core tubes are arranged in parallel, and the inlet header, the bottom flow header, and the overflow header are arranged in a parallel and staggered manner.

[0018] In another preferred embodiment, the ratio of the diameter of the bottom flow header to the diameter of the inlet header is 0.9-1.0, and the ratio of the diameter of the overflow header to the diameter of the inlet header is 0.1-0.4.

[0019] On the other hand, the present disclosure provides a method for reducing the pressure drop of the return sludge sorting unit in the biochemical tank by using the above-mentioned device, and the method includes the following steps: (i) Feed the return sludge from the biochemical tank into the inlet manifold at an inlet flow rate of 0.1 to 1 m / s; (ii) Uniformly feed the return sludge entering the inlet manifold into each swirl core tube distributed on the left and right sides of the inlet manifold at an inlet flow rate of 0.2 - 2 m / s; (iii) Control the underflow split ratio of the swirl core tube to be 95% - 99%, so that the heavy sludge after uniform sorting by the swirl core tube enters the swirl underflow manifold and returns to the front end of the biochemical tank, and the light sludge enters the swirl overflow manifold and is discharged as excess sludge; and (iv) The return sludge returning to the front end of the biochemical tank undergoes a complete biochemical cycle, and then continues to circulate and be sorted after precipitation at the end of the biochemical system.

[0020] In a preferred embodiment, in step (i), the return sludge is fed into the inlet manifold after being boosted by a sludge return pump.

[0021] In another preferred embodiment, in step (ii), the inlet flow rate of each swirl core tube is 0.5 - 2 m / s.

[0022] In another preferred embodiment, the underflow pressure after the swirl sorting of the return sludge is reduced by 0.03 - 0.05 MPa compared with the inlet pressure, and the overflow pressure is reduced by <0.1 MPa compared with the inlet pressure.

[0023] Beneficial effects: The present application uses the swirl sorting method to improve the sedimentation performance of the sludge. Through the combined treatment module of parallel swirl core tubes, by controlling the settings of parameters such as the spacing and inclination angle of the return sludge cyclone, the underflow manifold, the overflow manifold, and the inlet manifold, the feeding balance between the swirl core tubes and the minimization of the pressure drop are achieved, thereby improving the energy consumption of sewage treatment. Compared with the existing return sludge sorting technology, the present invention has the following advantages: (1) In terms of process equipment: Compared with other existing processes, the process change is not significant; and the cyclone in the device also has the advantages of simple structure, low cost, and easy maintenance; (2) In terms of energy consumption: Compared with the existing sludge sorting devices, the reasonable layout of each pipeline reduces the energy consumption in the treatment process and saves costs; (3) In terms of stability: The swirl sorting technology is a mechanical sorting method and does not affect the stability of the system operation; (4) In terms of environmental impact: By improving the treatment efficiency and quality of the sludge, the external discharge amount of the sludge is reduced, which helps to reduce the burden on the environment.

[0024] These and other features and advantages will become apparent by reading the following detailed description and referring to the associated drawings. It should be understood that the foregoing general description and the following detailed description are illustrative only and do not limit the various aspects claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic diagram of a sludge separation and treatment device according to a preferred embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The present application will be described in detail below with reference to the drawings, and the features of the present application will be further revealed in the following detailed description.

[0027] The "ranges" disclosed herein are defined in terms of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of a particular range. The ranges so defined can be inclusive or exclusive of the endpoints and can be combined in any manner, i.e., any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60 - 120 and 80 - 110 are listed for a particular parameter, ranges of 60 - 110 and 80 - 120 are also contemplated. Further, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, then the following ranges are all contemplated: 1 - 3, 1 - 4, 1 - 5, 2 - 3, 2 - 4, and 2 - 5. In the present application, unless otherwise specified, the numerical range "a - b" represents an abbreviated representation of any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "0 - 5" represents that all real numbers between "0 - 5" have been fully listed herein, and "0 - 5" is only an abbreviated representation of these numerical combinations. Additionally, when a certain parameter is expressed as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, the integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0028] In the present application, unless otherwise specified, all the embodiments and preferred embodiments mentioned herein can be combined with each other to form new technical solutions. In the present application, unless otherwise specified, all the technical features and preferred features mentioned herein can be combined with each other to form new technical solutions.

[0029] In the present application, unless otherwise specified, the terms "comprising" and "including" mentioned herein are open-ended and can also be closed-ended. For example, the said "comprising" and "including" can mean that other components not listed can also be included or contained, or can mean that only the listed components are included or contained.

[0030] In the description of this document, unless otherwise specified, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0031] After extensive and in-depth research, the inventors of this application found that as a commonly used biochemical wastewater treatment method, the activated sludge process mainly uses various microorganisms in it to adsorb and degrade organic matter in wastewater. During this process, excess sludge will be generated, and most of the sludge discharged from the secondary sedimentation tank still has strong biochemical treatment capabilities. If this kind of sludge is directly discharged without screening, not only resources will be wasted, but also the workload of subsequent sludge treatment will be increased; the present disclosure provides a reasonable control of the feeding method of the parallel cyclone combination module, the parallel cyclone combination method, and the operation scheme of the parallel cyclone. The cyclone separation module of the present disclosure can sort the excess sludge, leave the relatively high-quality sludge behind and return it to the front end of the anaerobic tank to achieve the cyclic biochemical treatment of sewage; this not only improves the sedimentation performance of the sludge, but also reduces the output of excess sludge, thus solving the long-existing problems in the above-mentioned prior art.

[0032] In the first aspect of this application, a device for reducing the pressure drop of the reflux sludge separation unit in a biochemical tank is provided. The device includes: An inlet manifold connected to the inlets of each cyclone core tube of the device, wherein the reflux sludge enters each cyclone core tube distributed on the left and right sides of the inlet manifold evenly through the inlet manifold; A bottom flow manifold connected to the bottom flow ports of each cyclone core tube, for discharging the bottom flow of the reflux sludge processed by the cyclone core tube to the front end of the biochemical tank; and An overflow manifold connected to the overflow ports of each cyclone core tube, for discharging the overflow of the reflux sludge processed by the cyclone core tube as excess sludge.

[0033] In this application, the ratio of the distance between each cyclone core tube to the nominal diameter of the cyclone core tube is 1-4, preferably 3, to ensure the uniformity of the feed flow rate of each single tube of the sludge cyclone.

[0034] In this application, the inclination angle of each cyclone core tube is 0-20°, preferably 10°, to ensure the uniformity of the feed flow rate of each single tube of the sludge cyclone.

[0035] In this application, the inclination angle of the inlet manifold is 5-15°, preferably 12°, to ensure the uniformity of the pressure drop of each single tube.

[0036] In this application, the ratio of the diameter of the underflow manifold to the diameter of the inlet manifold is 0.9 - 1.0, and the ratio of the diameter of the overflow manifold to the diameter of the inlet manifold is 0.1 - 0.4 to ensure the uniformity of the pressure drop of each single pipe.

[0037] In this application, the swirl core pipes are arranged in parallel, and the inlet manifold, underflow manifold, and overflow manifold are arranged in a parallel and staggered manner.

[0038] In the second aspect of this application, a method for reducing the pressure drop of the return sludge sorting unit in the biochemical pool is provided. The method includes the following steps: (a) The biochemical return sludge concentrated by process units such as the secondary sedimentation tank and boosted by the sludge return pump enters the parallel combined swirl module through the inlet manifold layout structure for sorting; (b) The return sludge entering the swirl module is controlled by the feed flow rate of a single cyclone to ensure that the return sludge enters each parallel cyclone evenly; (c) Through the cyclone split ratio parameter, the heavy sludge after uniform sorting enters the swirl underflow manifold and returns to the front end of the biochemical anaerobic or anoxic tank, while the light sludge enters the swirl overflow manifold and is discharged as excess sludge; and (d) The return sludge returning to the front end of the anaerobic or anoxic tank undergoes a complete biochemical cycle, and then continues to circulate and swirl for sorting after sedimentation at the end of the biochemical system.

[0039] In this application, after the return sludge is boosted by the return pump and enters the combined cyclone for sorting, the remaining activated sludge is returned to the front section of the anoxic tank after removing the decayed sludge. A small amount of inorganic matter and sand particles in the activated sludge are discharged through the underflow port. The sludge at the overflow port is sorted by the cyclone module to remove the suspended matter and loose sludge in the activated sludge and is discharged through the overflow port. The excess sludge is returned to the front section of the anoxic tank of the biochemical pool. The feed flow rate and split ratio during the sorting process are adjusted by corresponding valves respectively.

[0040] In this application, in step (a), the inlet flow rate of the return sludge when entering the swirl module through the inlet manifold is 0.1 - 1 m / s, preferably 0.5 m / s.

[0041] In this application, in step (b), the inlet flow rate of a single swirl core pipe is 0.2 - 2 m / s, preferably 0.5 - 2 m / s, and more preferably 1 m / s.

[0042] In this application, in step (c), the underflow split ratio of the swirl module is 95 - 99%.

[0043] In this application, the underflow pressure after the swirl sorting of the return sludge is reduced by 0.03 - 0.05 MPa compared to the inlet pressure, and the overflow pressure is reduced by <0.1 MPa compared to the inlet pressure.

[0044] Refer to the attached drawings below.

[0045] Figure 1 It is a schematic diagram of a sludge separation and treatment device according to a preferred embodiment of the present application. As Figure 1 shown, the device includes: an inlet manifold 1 connected to the inlets of each swirl core tube 2 of the device, wherein the return sludge enters the respective swirl core tubes distributed on the left and right sides of the inlet manifold evenly through the inlet manifold; a bottom flow manifold 3 connected to the underflow ports of each swirl core tube, for discharging the underflow of the return sludge after being processed by the swirl core tubes to the front end of the biochemical tank; and an overflow manifold 4 connected to the overflow ports of each swirl core tube, for discharging the overflow of the return sludge after being processed by the swirl core tubes as excess sludge.

[0046] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. The test methods without specific conditions noted in the following embodiments are generally carried out under conventional conditions or according to the conditions recommended by the manufacturer. Unless otherwise specified, all percentages and parts are by weight.

[0047] Example 1: When it is known that the return sludge enters the hydrocyclone group after being boosted by a sludge return pump for separation, the inlet flow rate of a single swirl core tube is 1.0 m / s, the inlet flow rate of the return sludge when entering the swirl module through the inlet manifold is 0.5 m / s, and the underflow split ratios of the swirl modules arranged in a parallel amplification manner are 95%, 97%, and 99% respectively, the average SVI (sludge volume index) of the effluent after the return sludge is separated by the hydrocyclone separation device is 105 mL / g, 110 mL / g, and 100 mL / g respectively; correspondingly, when the return sludge is processed by the swirl module, the underflow pressure drops are 0.036 MPa, 0.042 MPa, and 0.032 MPa respectively. It can be seen that under the condition of controlling the inlet flow rates of the swirl core tube and the inlet manifold to be stable and taking into account the pressure loss of the return sludge for separation at the same time, the underflow split ratios of the swirl modules arranged in a parallel amplification manner are 95%, 97%, and 99% respectively, and the control of the average SVI of the effluent and the control of the underflow pressure drop of the low-consumption swirl separation module for the return sludge are guaranteed.

[0048] Comparative Example 1-1: It is known that when the return sludge is boosted by a sludge return pump and enters the hydrocyclone group for separation, the inlet velocity of a single hydrocyclone core tube is 1.0 m / s, and the inlet velocity of the return sludge when it enters the hydrocyclone module through the inlet manifold is 0.5 m / s. When the underflow split ratios of the hydrocyclone modules arranged in a parallel amplification manner are 80% and 85% respectively, the average SVI of the effluent after the return sludge is separated by the hydrocyclone separation device are 215 mL / g and 180 mL / g respectively; correspondingly, when the return sludge is treated by the hydrocyclone module, the underflow pressure drops are 0.058 MPa and 0.063 MPa respectively. It can be seen that when the valve of the underflow manifold is fully closed, the flow rate of the overflow manifold will be less than 15 t / h. The control of the average SVI of the effluent and the control of the underflow pressure drop of the low-consumption hydrocyclone separation module for return sludge are both inferior to the three working conditions in Example 1, and the working conditions under these two split ratios are difficult to achieve.

[0049] Comparative Example 1-2: It is known that when the return sludge is boosted by a sludge return pump and enters the hydrocyclone group for separation, the inlet velocity of a single hydrocyclone core tube is 1.0 m / s, and the inlet velocity of the return sludge when it enters the hydrocyclone module through the inlet manifold is 0.5 m / s. When the underflow split ratio of the hydrocyclone module arranged in a parallel amplification manner is greater than 99%, when the return sludge is treated by the hydrocyclone module, the underflow pressure drop is 0.025 MPa. It can be seen that the control of the average SVI of the effluent and the control of the underflow pressure drop of the low-consumption hydrocyclone separation module for return sludge are both inferior to the three working conditions in Example 1, and when the split ratio is greater than 99%, the situation of overflow cut-off will occur, which does not conform to engineering operations.

[0050] Example 2: It is known that when the inlet velocity of the return sludge when it enters the hydrocyclone module through the inlet manifold is 0.5 m / s, and the underflow split ratio of the hydrocyclone module arranged in a parallel amplification manner is 97%, when the inlet velocities of a single hydrocyclone core tube are 0.2 m / s, 0.5 m / s, 1.0 m / s, and 2.0 m / s respectively, the average SVI of the effluent after the return sludge is separated by the hydrocyclone separation device are 92 mL / g, 108 mL / g, 100 mL / g, and 87 mL / g respectively; correspondingly, when the return sludge is treated by the hydrocyclone module, the underflow pressure drops are 0.041 MPa, 0.035 MPa, 0.031 MPa, and 0.047 MPa respectively. It can be seen that under the condition of controlling the inlet velocity of the inlet manifold to be stable and at the same time taking into account the pressure loss during the separation of the return sludge, when the inlet velocities of a single hydrocyclone core tube are 0.2 m / s, 0.5 m / s, 1.0 m / s, and 2.0 m / s respectively, the control of the average SVI of the effluent and the control of the underflow pressure drop of the low-consumption hydrocyclone separation module for return sludge are both guaranteed, and the hydrocyclone separation device for return sludge has a good separation effect.

[0051] Comparative Example 2: It is known that when the return sludge enters the cyclone module through the inlet header, the inlet flow velocity is 0.5 m / s, the underflow split ratio of the cyclone modules arranged in a parallel amplification manner is 97%, and the inlet flow velocities of a single cyclone core tube are 0.1 m / s and 3 m / s respectively. The average SVI of the effluent after the return sludge is separated by the cyclone separation device is 213 mL / g and 158 mL / g respectively; correspondingly, when the return sludge is treated by the cyclone module, the underflow pressure drops are 0.025 MPa and 0.056 MPa respectively. It can be seen that under the condition of controlling the inlet flow velocity of the inlet header to be stable and taking into account the pressure loss during the separation of the return sludge, both the control of the average SVI of the effluent and the control of the underflow pressure drop of the low-consumption cyclone separation module for return sludge are inferior to the four working conditions in Example 2; when the return sludge is separated by the cyclone module, the separation difficulty between the light sludge and the heavy sludge increases, and the separation effect is not good.

[0052] Example 3: It is known that when the return sludge is boosted by a sludge return pump and then enters the cyclone group for separation, the inlet flow velocity of a single cyclone core tube is 1.0 m / s, and the underflow split ratio of the cyclone modules arranged in a parallel amplification manner is 97%. When the inlet flow velocities of the return sludge entering the cyclone module through the inlet header are 0.1 m / s, 0.2 m / s, 0.5 m / s, and 1 m / s respectively, the average SVI of the effluent after the return sludge is separated by the cyclone separation device is 88 mL / g, 93 mL / g, 112 mL / g, and 105 mL / g respectively; correspondingly, when the return sludge is treated by the cyclone module, the underflow pressure drops are 0.034 MPa, 0.040 MPa, 0.037 MPa, and 0.045 MPa respectively. It can be seen that under the condition of controlling the inlet flow velocity of the cyclone core tube to be stable and taking into account the pressure loss during the separation of the return sludge, when the inlet flow velocities of the return sludge entering the cyclone module through the inlet header are 0.1 m / s, 0.2 m / s, 0.5 m / s, and 1 m / s respectively, both the control of the average SVI of the effluent and the control of the underflow pressure drop of the low-consumption cyclone separation module for return sludge are well controlled, and the cyclone separation device for return sludge has a good separation effect.

[0053] Comparative Example 3: When it is known that the return sludge enters the hydrocyclone group after being pressurized by a sludge return pump for separation, the inlet velocity of a single hydrocyclone core tube is 1.0 m / s, and the underflow split ratio of the hydrocyclone module arranged in a parallel amplification manner is 97%. When the inlet velocities of the return sludge entering the hydrocyclone module through the feed manifold are 0.05 m / s and 1.5 m / s respectively, the average SVI of the effluent after the return sludge is separated by the hydrocyclone separation device are 167 mL / g and 223 mL / g respectively. Correspondingly, when the return sludge is treated by the hydrocyclone module, the underflow pressure drops are 0.023 MPa and 0.063 MPa respectively. It can be seen that under the condition of controlling the inlet velocity of the hydrocyclone core tube to be stable and taking into account the pressure loss during the separation of the return sludge at the same time, both the control of the average SVI of the effluent and the control of the underflow pressure drop of the low-consumption hydrocyclone separation module for the return sludge are inferior to the four working conditions in Example 3; the return sludge is not efficiently separated by the hydrocyclone separation module during the separation process, which is not conducive to the subsequent circulating biochemical treatment of sewage and does not achieve the actual problem of energy consumption reduction.

[0054] Examples 4 - 6 and Comparative Examples 4 - 6: Experimental conditions: When the return sludge enters the hydrocyclone group after being pressurized by a sludge return pump for separation, the inlet velocity of a single hydrocyclone core tube is 1.0 m / s, the inlet velocity of the return sludge entering the hydrocyclone module through the inlet manifold is 0.5 m / s, and the underflow split ratio of the hydrocyclone module arranged in a parallel amplification manner is 97%.

[0055] Example 4: It is known that the inclination angles of the hydrocyclone core tubes in the return sludge hydrocyclone separation module are 10°, and the inclination angle of the inlet manifold is 12°. When the ratios of the spacing between the hydrocyclone core tubes to the nominal diameter of the hydrocyclone core tube are 1, 2, and 4 respectively, when the return sludge is treated by the hydrocyclone module, the underflow pressure drops are 0.033 MPa, 0.042 MPa, and 0.038 MPa respectively, and the overflow pressure drops are 0.082 MPa, 0.090 MPa, and 0.087 MPa respectively. It can be seen that under the condition of ensuring the stability of the inlet velocities of the hydrocyclone core tubes and the inlet manifold and the split ratio and controlling the inclination angles of the inlet manifold and the hydrocyclone core tubes to remain unchanged, the underflow pressure drop and the overflow pressure drop are well controlled, and the energy consumption during the hydrocyclone separation process is reduced.

[0056] Comparative Example 4: It is known that the inclination angle of each cyclone core tube in the return sludge cyclone separation module is 10°, and the inclination angle of the inlet header is 12°. When the ratio of the distance between each cyclone core tube to the nominal diameter of the cyclone core tube is 0.5, the effective and reasonable layout of the equipment cannot be achieved; when the ratio of the distance between each cyclone core tube to the nominal diameter of the cyclone core tube is 6, when the return sludge is treated by the cyclone module, the underflow pressure drop is 0.07 MPa and the overflow pressure drop is 0.12 MPa. It can be seen that under the condition of ensuring the stability of the inlet flow velocity of the cyclone core tube, the inlet header and the split ratio and controlling the inclination angles of the inlet header and the cyclone core tube to remain unchanged, the control of the underflow pressure drop and the overflow pressure drop is inferior to the three working conditions in Example 4, which is contrary to the ultimate purpose of the present invention and does not achieve the reduction of energy consumption in the cyclone separation process as much as possible.

[0057] Example 5: It is known that the ratio of the distance between each cyclone core tube to the nominal diameter of the cyclone core tube is 3, and the inclination angle of the inlet header is 12°. When the inclination angles of each cyclone core tube in the return sludge cyclone separation module are 5°, 10°, and 20° respectively, when the return sludge is treated by the cyclone module, the underflow pressure drops are 0.040 MPa, 0.035 MPa, and 0.045 MPa respectively, and the overflow pressure drops are 0.08 MPa, 0.072 MPa, and 0.093 MPa respectively. It can be seen that under the condition of ensuring the stability of the inlet flow velocity of the cyclone core tube, the inlet header and the split ratio and controlling the inclination angle of the inlet header and the ratio of the distance between each cyclone core tube to the nominal diameter of the cyclone core tube to remain unchanged, the underflow pressure drop and the overflow pressure drop are well controlled, and the reduction of energy consumption in the cyclone separation process is achieved.

[0058] Comparative Example 5: It is known that the ratio of the distance between each cyclone core tube to the nominal diameter of the cyclone core tube is 3, and the inclination angle of the inlet header is 12°. When the inclination angle of each cyclone core tube in the return sludge cyclone separation module is 30°, when the return sludge is treated by the cyclone module, the underflow pressure drop is 0.12 MPa and the overflow pressure drop is 0.04 MPa. It can be seen that under the condition of ensuring the stability of the inlet flow velocity of the cyclone core tube, the inlet header and the split ratio and controlling the inclination angle of the inlet header and the ratio of the distance between each cyclone core tube to the nominal diameter of the cyclone core tube to remain unchanged, the control of the underflow pressure drop and the overflow pressure drop is inferior to the three working conditions in Example 5, and it is difficult to control the underflow pressure drop and the overflow pressure drop within a reasonable range. Under this condition, there is still a problem of too high treatment energy consumption.

[0059] Example 6: Given that the ratio of the spacing between the swirl core tubes to the nominal diameter of the swirl core tubes is 3 and the inclination angle of the swirl core tubes is 10°, when the inclination angles of the inlet header pipes in the return sludge swirl separation module are 5°, 10°, and 15° respectively, when the return sludge is treated by the swirl module, the underflow pressure drops are 0.046 MPa, 0.036 MPa, and 0.041 MPa respectively, and the overflow pressure drops are 0.060 MPa, 0.082 MPa, and 0.076 MPa respectively. It can be seen that under the conditions of ensuring the stable inlet flow velocity of the swirl core tubes and the inlet header pipes and the stable split ratio and controlling the inclination angle of the swirl core tubes and keeping the spacing between the swirl core tubes and the nominal diameter of the swirl core tubes unchanged, the underflow pressure drop and the overflow pressure drop are well controlled, and the energy consumption in the swirl separation process is reduced.

[0060] Comparative Example 6: Given that the ratio of the spacing between the swirl core tubes to the nominal diameter of the swirl core tubes is 3 and the inclination angle of the swirl core tubes is 10°, when the inclination angles of the inlet header pipes in the return sludge swirl separation module are 3° and 20° respectively, when the return sludge is treated by the swirl module, the underflow pressure drops are 0.02 MPa and 0.06 MPa respectively, and the overflow pressure drops are 0.12 MPa and 0.15 MPa respectively. It can be seen that under the conditions of ensuring the stable inlet flow velocity of the swirl core tubes and the inlet header pipes and the stable split ratio and controlling the inclination angle of the swirl core tubes and keeping the spacing between the swirl core tubes and the nominal diameter of the swirl core tubes unchanged, the control of the underflow pressure drop and the overflow pressure drop is inferior to the three working conditions in Example 6. The underflow pressure drop and the overflow pressure drop are not well controlled due to the optimization of other experimental conditions, and the energy consumption in the sludge return separation process is not reduced accordingly.

[0061] Finally, it is necessary to state here that the above examples are only used to further illustrate the technical solutions of the present invention in detail, and should not be construed as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention all fall within the protection scope of the present invention.

Claims

1. A device for reducing the pressure drop of a biochemical pool return sludge sorting unit, characterized in that: The device includes: An inlet manifold (1) connected to the inlets of each cyclone core tube (2) of the device, wherein the return sludge evenly enters each cyclone core tube distributed on the left and right sides of the inlet manifold through the inlet manifold; An underflow manifold (3) connected to the underflow outlets of each cyclone core tube, used to discharge the underflow of the return sludge treated by the cyclone core tube to the front end of the biochemical pool; and The overflow manifold (4) connected to the overflow ports of the cyclone core tubes is used to discharge the overflow of the return sludge after being treated by the cyclone core tubes as residual sludge. The ratio of the spacing between the swirl core tubes to the nominal diameter of the swirl core tubes is 1-4, the inclination angle of each swirl core tube is 0-20°, and the inclination angle of the inlet manifold is 5-15°.

2. The device according to claim 1, characterized in that The cyclone core pipes are arranged in parallel, and the inlet manifold, the underflow manifold and the overflow manifold are arranged in parallel and staggered.

3. The device according to claim 1, characterized in that The ratio of the underflow header diameter to the inlet header diameter is 0.9-1.0, and the ratio of the overflow header diameter to the inlet header diameter is 0.1-0.

4.

4. A method for reducing the pressure drop of a biochemical pool return sludge sorting unit using the device according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: (i) sending the return sludge from the biochemical pool into the inlet manifold at an inlet flow rate of 0.1-1 m / s; (ii) The return sludge entering the inlet manifold is evenly fed into the cyclone core tubes distributed on the left and right sides of the inlet manifold at an inlet flow rate of 0.2-2 m / s; (iii) controlling the underflow split ratio of the cyclone core tube to be 95-99%, so that the heavy sludge evenly sorted by the cyclone core tube enters the cyclone underflow header and returns to the front end of the biochemical tank, and the light sludge enters the cyclone overflow header and is discharged as excess sludge; and (iv) The return sludge returned to the front end of the biochemical pool undergoes a complete biochemical cycle and then continues to circulate and be sorted after settling at the end of the biochemical system.

5. The method according to claim 4, characterized in that In step (i), the return sludge is pressurized by the sludge return pump and then sent to the inlet manifold.

6. The method according to claim 4, characterized in that In step (ii), the inlet flow velocity of each cyclone core tube is 0.5-2 m / s.

7. The method according to claim 4, characterized in that The underflow pressure of the return sludge after cyclone separation is 0.03-0.05 MPa lower than the inlet pressure, and the overflow pressure is <0.1 MPa lower than the inlet pressure.

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