Sludge concentration and quality selection system, control method and sewage treatment system and method

Abstract

The invention provides a sludge concentration and quality selection system, a control method and a sewage treatment system and method.The sludge concentration and quality selection system is applied to an integrated reaction precipitation device inoculated with activated sludge and used for receiving sludge discharged by the integrated reaction precipitation device and concentrating or screening the sludge. Comprising a sludge pre-concentration tank and a sludge quality selection device, and the sludge concentration and quality selection system has at least two working modes including a sludge quality selection mode and a sludge concentration mode. According to the sludge concentration and quality selection system, the control method and the sewage treatment system and method, sludge of the integrated reaction precipitation device can be concentrated and then discharged, the concentration of residual sludge is increased, and the subsequent sludge treatment efficiency is improved; the sludge in the integrated reaction precipitation device can be directionally screened, and the sludge with poor settling performance is discharged, so that the water treatment efficiency and effect are improved.

Description

Technical Field

[0001] This application relates to the technical field of sewage treatment, and in particular to a sludge concentration and quality selection system, a control method, a sewage treatment system and a method. Background Art

[0002] An integrated reaction and sedimentation device is a sewage treatment device that integrates aeration and sedimentation, that is, aeration and sedimentation are carried out in the same device or reaction tank. When using the existing integrated reaction and sedimentation device for sewage treatment, generally the sedimentation time is limited and no additional sedimentation tank is provided. Therefore, there is a problem that the concentration of the remaining sludge discharged is relatively low. When the concentration of the remaining sludge is relatively low, it will further affect the subsequent treatment of the sludge, resulting in problems such as a long treatment process, a long time, and high energy consumption. At the same time, when the sludge concentration in the reaction system is relatively low, it will also cause problems such as low denitrification and phosphorus removal efficiency in the system, affecting the sewage treatment efficiency and effect. Summary of the Invention

[0003] In view of this, the purpose of this application is to provide a sludge concentration and quality selection system, a control method, a sewage treatment system and a method to solve the above technical problems.

[0004] In the first aspect of this application, a sludge concentration and quality selection system is provided, which is applied to an integrated reaction and sedimentation device inoculated with activated sludge; the sludge concentration and quality selection system is used to receive the sludge discharged from the integrated reaction and sedimentation device and concentrate or screen the sludge, and includes:

[0005] A sludge pre-concentration tank, which is used to pre-concentrate the sludge by separating the sludge from the water, is connected to the integrated reaction and sedimentation device through a first sludge discharge pipeline, and the upper part is connected to a pre-concentration water discharge pipeline for discharging the supernatant from the sludge pre-concentration tank;

[0006] A sludge quality selection device, which is used to concentrate the sludge by separating the sludge from the water or perform swirl screening, is provided with a first inlet on the side wall, a bottom flow port at the bottom, and an overflow port at the top. The first inlet is respectively connected to the integrated reaction and sedimentation device and the sludge pre-concentration tank through the second sludge discharge pipeline and the pre-concentration sludge discharge pipeline; the bottom flow port is respectively connected to the integrated reaction and sedimentation device and an external sludge storage tank through a first return pipeline and a third sludge discharge pipeline; the overflow port is respectively connected to the integrated reaction and sedimentation device and an external sludge storage tank through a second return pipeline and a fourth sludge discharge pipeline;

[0007] The sludge concentration and quality selection system has at least two working modes including a sludge quality selection mode and a sludge concentration mode; in the sludge quality selection mode, the first sludge discharge pipeline, the sludge pre-concentration tank, the pre-concentrated sludge discharge pipeline, the pre-concentrated water outlet pipeline, the third sludge discharge pipeline and the second return pipeline are in a non-enabled state; in the sludge concentration mode, the second sludge discharge pipeline, the first return pipeline, and the fourth sludge discharge pipeline are in a non-enabled state.

[0008] Further, it further includes:

[0009] A chemical dosing device, which is connected to the first sludge discharge pipeline through a chemical dosing pipeline, and is used to add a flocculant to the sludge pre-concentration tank;

[0010] And / or, a backwashing device, which is connected to the third sludge discharge pipeline through a backwashing pipeline, and is used to backwash the sludge quality selection device.

[0011] In the second aspect of the present application, a control method for a sludge concentration and quality selection system is provided, which is applied to the sludge concentration and quality selection system in the first aspect; the control method includes:

[0012] Monitor the sludge concentration, sludge retention time, sludge settling ratio, sludge level and reaction cycle during the sewage treatment process of the integrated reaction and sedimentation device;

[0013] In response to the sludge concentration in the integrated reaction and sedimentation device being greater than the first concentration threshold or the sludge retention time being greater than the preset number of days, and the reaction cycle of the integrated reaction and sedimentation device being in the first preset cycle, start the sludge concentration and quality selection system and operate it in the sludge concentration mode;

[0014] In response to the ratio of the sludge settling ratio to the sludge concentration in the integrated reaction and sedimentation device being greater than the first preset ratio or the sludge level being greater than the first preset height, and the reaction cycle being in the second preset cycle, start the sludge concentration and quality selection system and operate it in the sludge quality selection mode.

[0015] Further, the operation steps of the sludge concentration mode include:

[0016] Start the sludge pre-concentration tank, and control the integrated reaction and sedimentation device to discharge sludge to the sludge pre-concentration tank through the first sludge discharge pipeline;

[0017] Control the sludge to stay in the sludge pre-concentration tank for a certain time for water separation and sedimentation, monitor the sludge level in the sludge pre-concentration tank and the influent sludge concentration of the sludge pre-concentration tank, and open the pre-concentrated water outlet pipeline to discharge the upper clear liquid through the sludge pre-concentration tank;

[0018] In response to the sludge level in the sludge pre-concentration tank being greater than or equal to a second preset height and the influent sludge concentration in the sludge pre-concentration tank being greater than or equal to a second concentration threshold, start the sludge quality selection device, and control the sludge pre-concentration tank to discharge sludge to the sludge quality selection device through the pre-concentration sludge discharge pipeline and the first inlet;

[0019] Use the sludge quality selection device to separate and concentrate the sludge. The concentrated sludge is discharged into an external sludge storage tank through the underflow port and the third sludge discharge pipeline, and the upper layer of the sludge-water mixture flows back to the integrated reaction sedimentation device through the overflow port and the second return pipeline.

[0020] Further, the operation steps of the sludge concentration mode further include:

[0021] In response to the sludge staying in the sludge pre-concentration tank for more than a preset time, the sludge level in the sludge pre-concentration tank is still less than the second preset height, or the influent sludge concentration in the sludge pre-concentration tank is still less than the second concentration threshold, start the dosing device to add flocculant to the sludge pre-concentration tank.

[0022] Further, the operation steps of the sludge quality selection mode include:

[0023] Start the sludge quality selection device, and control the integrated reaction sedimentation device to discharge sludge to the sludge quality selection device through the second sludge discharge pipeline and the first inlet;

[0024] Use the sludge quality selection device to perform swirl screening on the incoming sludge. The bottom sludge flows back to the integrated reaction sedimentation device through the underflow port and the first return pipeline; the upper layer of sludge is discharged into the external sludge storage tank through the overflow port and the fourth sludge discharge pipeline.

[0025] Further, it further includes:

[0026] During the operation of the sludge quality selection device, monitor the sludge concentration, flow rate, and pressure at the underflow port and the first inlet;

[0027] In response to the ratio of the sludge concentration at the underflow port to that at the first inlet being less than a second preset ratio, or the ratio of the flow rate at the underflow port to that at the first inlet being greater than a third preset ratio or less than a fourth preset ratio, or the pressure difference between the first inlet and the underflow port being greater than or equal to a preset difference, control the backwashing device to start and backwash the sludge quality selection device through the backwashing pipeline.

[0028] Further, the operation steps of the sludge quality selection mode further include:

[0029] Monitor the sludge particle size in the integrated reaction sedimentation device;

[0030] After the operation of the sludge quality selection device reaches the target cycle, the ratio of the sludge sedimentation ratio to the sludge concentration in the integrated reaction and sedimentation device is still greater than the first preset ratio;

[0031] Add microbial carriers to the integrated reaction and sedimentation device until the sludge particle size in the integrated reaction and sedimentation device meets the preset particle size value, or the ratio of the sludge sedimentation ratio to the sludge concentration is less than or equal to the preset ratio.

[0032] In the third aspect of the present application, a sewage treatment system is further provided, including an integrated reaction and sedimentation device and the sludge thickening and quality selection system described in the first aspect, and further including:

[0033] A water inlet pipeline and a water outlet pipeline respectively communicating with the integrated reaction and sedimentation device. The water inlet pipeline is used to introduce the sewage to be treated into the integrated reaction and sedimentation device, and the water outlet pipeline is used to discharge the treated sewage to the next process.

[0034] In the fourth aspect of the present application, a sewage treatment method is further provided, which is applied to the sewage treatment system described in the third aspect. The method includes:

[0035] Introduce the sewage to be treated into the integrated reaction and sedimentation device inoculated with activated sludge through the water inlet pipeline, and the treated sewage is discharged to the next process through the water outlet pipeline;

[0036] During the treatment process of the integrated reaction and sedimentation device, use the control method of the sludge thickening and quality selection system described in the second aspect to control the sludge thickening and quality selection system, so as to concentrate or screen the sludge according to the state of the activated sludge in the integrated reaction and sedimentation device.

[0037] As can be seen from the above, the present application provides a sludge concentration and quality selection system, a control method, a sewage treatment system and a method. By setting a sludge pre-concentration tank and a sludge quality selection device, it is possible to concentrate and perform cyclone screening on the sludge in the integrated reaction sedimentation device. When the integrated reaction sedimentation device needs to discharge surplus sludge, the sludge concentration screening system is started in the sludge concentration mode, and the surplus sludge discharged from the integrated reaction sedimentation device is separated and concentrated by mud and water and then discharged to the external sludge storage tank, thereby increasing the concentration of the surplus sludge, reducing the subsequent treatment process and energy consumption of the surplus sludge, and improving the subsequent sludge dewatering efficiency; when the sedimentation performance of the integrated reaction sedimentation device is poor, the sludge concentration screening system is started in the sludge quality selection mode, and the sludge in the integrated reaction sedimentation device is subjected to cyclone screening, the sludge with poor sedimentation performance and poor flocculation performance is discharged from the system, and the sludge with good sedimentation performance and good flocculation performance is re-circulated to the integrated reaction sedimentation device to continue treating the sewage, thereby improving the sedimentation performance and sludge concentration of the activated sludge in the integrated reaction sedimentation device, and further improving the sewage treatment efficiency and treatment effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the present application or related technologies, the following will briefly introduce the drawings required for use in the description of the embodiments or related technologies. Obviously, the drawings in the following description are only the embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0039] Figure 1 Schematic diagram of the sludge concentration and quality selection system in the embodiment of the present application;

[0040] Figure 2 Schematic diagram of the structure of the hydrocyclone in the embodiment of the present application;

[0041] Figure 3 Schematic diagram of an electronic device in the embodiment of the present application.

[0042] Description of the reference numerals: 1 - integrated reaction sedimentation device; 2 - sludge pre-concentration tank; 201 - second inlet; 202 - central cylinder; 203 - baffle; 3 - sludge quality selection device; 301 - first inlet; 302 - underflow port; 303 - overflow port; 4 - first sludge discharge pipeline; 5 - pre-concentration sludge discharge pipeline; 6 - second sludge discharge pipeline; 7 - third sludge discharge pipeline; 8 - first reflux pipeline; 9 - fourth sludge discharge pipeline; 10 - second reflux pipeline; 11 - backwashing device; 12 - backwashing pipeline; 13 - chemical dosing device; 14 - chemical dosing pipeline; 15 - water inlet pipeline; 16 - water outlet pipeline; 17 - pre-concentration water outlet pipeline. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0043] To make the objectives, technical solutions and advantages of this application more clear and understandable, the following further elaborates on this application in detail with reference to specific embodiments and the accompanying drawings.

[0044] It should be noted that unless otherwise defined, the technical terms or scientific terms used in the embodiments of this application should have the ordinary meanings understood by those with ordinary skills in the field to which this application belongs. The "first", "second" and similar terms used in the embodiments of this application do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "including" or "comprising" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. Words such as "connected" or "linked" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right", etc. are only used to represent relative position relationships. When the absolute position of the object being described changes, the relative position relationship may also change accordingly.

[0045] The activated sludge process is a method for biological treatment of sewage with activated sludge as the main body. It has a research and application history of more than 100 years. It can remove dissolved and colloidal biodegradable organic matter from sewage, as well as suspended solids and other substances that can be adsorbed by activated sludge. It has the characteristics of wide adaptability to water quality and quantity, flexible operation modes, good controllability, high treatment efficiency, low cost, etc., and has become the main body of sewage biological treatment methods.

[0046] Activated sludge is a flocculent sludge particle formed by the mixing of microbial populations such as bacteria, fungi, protozoa, and metazoans with suspended substances and colloidal substances in sewage. It has a strong ability to adsorb and decompose organic matter and good sedimentation performance, and is called activated sludge because of its biochemical activity. The activated sludge process is a type of biological treatment method that uses organic pollutants in sewage as a culture medium, continuously cultivates activated sludge under aerobic conditions, and uses its adsorption, coagulation and oxidation decomposition functions to purify organic pollutants in sewage.

[0047] After years of development, the activated sludge process has undergone continuous improvement, innovation, and proliferation, giving rise to various types of activated sludge processes and reaction devices. The integrated reaction and sedimentation device 1 is a device that combines aeration and sedimentation, that is, aeration is first carried out in the same reaction device, then sedimentation, and finally the supernatant after sedimentation is discharged, and the activated sludge remains in the reaction device to continue treating the next batch of sewage. During the operation of the integrated reaction and sedimentation device 1, the operation mode consists of 4 basic processes: water inlet, aeration, standing, and drainage, which form a cycle, that is, different operations with different purposes are carried out at different times in a single reaction device. Although the flow state is completely mixed, in terms of pollutant degradation, it is a plug flow in time. The integrated reaction and sedimentation device 1 reduces the floor area of the treatment process, reduces the pipeline connection between various treatment equipment and the use of various consumables in the traditional AAO process, and is a sewage treatment process that is economical and intensive.

[0048] During the reaction process of the integrated reaction and sedimentation device 1, since process parameters such as aeration volume are adjusted or the concentration of nutrients in the sewage will affect the types and growth rates of microorganisms in the activated sludge. After the device has been operating for a period of time, in order to maintain the sludge in the integrated reaction and sedimentation device 1 in a better treatment performance, it is necessary to regularly or irregularly discharge a part of the sludge in the integrated reaction and sedimentation device 1. The discharged excess sludge usually contains a high water content, is large in volume and inconvenient to transport, and also contains substances such as volatile substances, ash, pathogens, and toxic substances. Therefore, a series of subsequent treatments are also required for the discharged excess sludge, including reducing the volume of the sludge, reducing its water content, making it convenient for transportation, digestion, dehydration, and comprehensive utilization; carrying out sanitary and stabilization treatments to remove organic matter, pathogens, and other harmful substances to prevent "secondary pollution sources" and environmental pollution; improving the composition and properties of the sludge for resource utilization, etc.

[0049] Since the sedimentation process is directly completed in the integrated reaction and sedimentation device 1, when the sedimentation time is too long, the sewage treatment efficiency is low; while when the sedimentation time is too short, it will lead to a low sludge concentration and a low concentration of the discharged excess sludge. When the sludge concentration of the discharged excess sludge is too low, the following problems will be brought to the subsequent treatment of the excess sludge: (1) It affects the subsequent sludge dewatering efficiency, that is, it may not be able to meet the requirements of the excess sludge water content, resulting in the inability to transport the excess sludge out; (2) It causes the lengthening of the excess sludge treatment process, requires a larger floor area, and will increase the consumption of chemicals; (3) It causes the insufficient capacity of the sludge dewatering machine, resulting in the solid recovery rate of the dewatering machine being lower than 80% for a long time, leading to the generation of a large amount of leachate, increasing the power consumption and energy consumption of the dewatering machine. The above problems greatly limit the subsequent treatment and disposal of the excess sludge.

[0050] In addition, the sedimentation performance of the activated sludge in the integrated reaction and sedimentation device 1 is affected by the influent water quality, aeration time, etc. When the sedimentation performance of the sludge deteriorates, it is difficult for the sludge to settle, which will also lead to the problem of a decrease in the sludge concentration. On this basis, the sludge has poor compressibility, the discharge of the supernatant is restricted, the cement ratio decreases, the amount of sewage treated in each operation cycle decreases, thereby affecting the sewage treatment efficiency. At the same time, when the sludge concentration decreases, the denitrification and phosphorus removal efficiency of the sewage decreases, and it is easy to cause the nitrogen and phosphorus content in the effluent to be too high, thereby affecting the sewage treatment effect.

[0051] The sequencing batch reactor is a typical integrated reaction and sedimentation device 1. The activated sludge process implemented by using the sequencing batch reactor (SBR) is usually called the sequencing batch activated sludge process (SBR process). The SBR process uses intermittent aeration and is one of the important methods for urban sewage treatment, industrial (such as petroleum, chemical, food, pharmaceutical industries, etc.) sewage treatment and nutrient element removal. In addition to the sequencing batch reactor, the integrated reaction sedimentation tank is also a typical integrated reaction and sedimentation device 1. In order to further improve the sewage treatment effect in the biochemical system, in some processes, an integrated reaction sedimentation tank is added to the secondary sedimentation tank, and aeration is carried out in the integrated reaction sedimentation tank to promote the reaction between the activated sludge and the sewage, and then precipitation is carried out and the treated sewage is discharged from the system. Whether it is an integrated reaction sedimentation tank or a sequencing batch reactor, the above problems exist.

[0052] In view of this, the present application provides a sludge concentration and quality selection system, as Figure 1 shown, which is applied to the integrated reaction and sedimentation device 1 inoculated with activated sludge, and can simultaneously improve the sludge concentration, sewage treatment efficiency and sewage treatment effect of the integrated reaction and sedimentation device 1. The sludge concentration and quality selection system is used to receive the sludge discharged from the integrated reaction and sedimentation device 1 and concentrate or screen the sludge, and includes:

[0053] A sludge pre-concentration tank 2, which is used to pre-concentrate the sludge by separating the sludge from the water, is connected to the integrated reaction and sedimentation device 1 through a first sludge discharge pipeline 4, and the upper part is connected to a pre-concentration water discharge pipeline 17 for discharging the supernatant from the sludge pre-concentration tank 2;

[0054] The sludge quality selection device 3 is used for sludge-water separation and concentration or cyclone screening of sludge. The side wall is provided with a first inlet 301, the bottom is provided with an underflow port 302, and the top is provided with an overflow port 303. The first inlet 301 is respectively communicated with the integrated reaction sedimentation device 1 and the sludge pre-concentration tank 2 through the second sludge discharge pipeline 6 and the pre-concentration sludge discharge pipeline 5; the underflow port 302 is respectively communicated with the integrated reaction sedimentation device 1 and an external sludge storage tank through the first return pipeline 8 and the third sludge discharge pipeline 7; the overflow port 303 is respectively communicated with the integrated reaction sedimentation device 1 and an external sludge storage tank through the second return pipeline 10 and the fourth sludge discharge pipeline 9;

[0055] The sludge concentration and quality selection system has at least two working modes including a sludge quality selection mode and a sludge concentration mode; in the sludge quality selection mode, the first sludge discharge pipeline 4, the sludge pre-concentration tank 2, the pre-concentration sludge discharge pipeline 5, the pre-concentration water discharge pipeline 17, the third sludge discharge pipeline 7 and the second return pipeline 10 are in a non-enabled state; in the sludge concentration mode, the second sludge discharge pipeline 6, the first return pipeline 8, and the fourth sludge discharge pipeline 9 are in a non-enabled state.

[0056] By setting the sludge pre-concentration tank 2 and the sludge quality selection device 3, this application can realize the concentration and cyclone screening of the sludge in the integrated reaction sedimentation device 1. When the integrated reaction sedimentation device 1 needs to discharge the surplus sludge, the sludge concentration and screening system is started in the sludge concentration mode, and the surplus sludge discharged from the integrated reaction sedimentation device 1 is subjected to sludge-water separation and concentration and then discharged to an external sludge storage tank, thereby increasing the concentration of the surplus sludge, reducing the subsequent treatment process and energy consumption of the surplus sludge, and improving the subsequent sludge dewatering efficiency; when the sedimentation performance of the integrated reaction sedimentation device 1 is poor, the sludge concentration and screening system is started in the sludge quality selection mode, and the sludge in the integrated reaction sedimentation device 1 is subjected to cyclone screening, the sludge with poor sedimentation performance and poor flocculation performance is discharged from the system, and the sludge with good sedimentation performance and good flocculation performance is re-circulated to the integrated reaction sedimentation device 1 to continue treating the sewage, thereby improving the sedimentation performance and sludge concentration of the activated sludge in the integrated reaction sedimentation device 1, and further improving the sewage treatment efficiency and treatment effect.

[0057] In the sludge thickening mode, the second sludge discharge pipeline 6, the first reflux pipeline 8, and the fourth sludge discharge pipeline 9 are in a non-enabled state. The sludge discharged from the integrated reaction and sedimentation device 1 enters the sludge pre-thickening tank 2 through the first sludge discharge pipeline 4. Preliminary separation of mud and water is carried out in the sludge pre-thickening tank 2 to achieve pre-thickening. The supernatant is discharged through the pre-thickened water discharge pipeline 17, and the settled sludge enters the sludge quality selection device 3 through the pre-thickened sludge discharge pipeline 5 for further separation of mud and water to achieve secondary thickening. In the sludge quality selection device 3, due to high-speed rotation, the heavier sludge is thrown to the outer wall and sinks, and then is discharged to the external sludge storage tank through the bottom flow port 302 and the third sludge discharge pipeline 7 for subsequent treatment; while the sewage and the sludge with lower concentration overflow through the overflow port 303 and are refluxed to the integrated reaction and sedimentation device 1 through the second reflux pipeline 10 to continue participating in the reaction. Thus, during the sludge discharge process of the integrated reaction and sedimentation device 1, the concentration and dehydration of the excess sludge are achieved, the sludge concentration is increased, the subsequent treatment process and energy consumption of the excess sludge are reduced, and the subsequent sludge dewatering efficiency is improved.

[0058] In the sludge quality selection mode, the first sludge discharge pipeline 4, the sludge pre-thickening tank 2, the pre-thickened sludge discharge pipeline 5, the pre-thickened water discharge pipeline 17, the third sludge discharge pipeline 7, and the second reflux pipeline 10 are in a non-enabled state. The sludge of the integrated reaction and sedimentation device 1 directly enters the sludge quality selection device 3 through the second sludge discharge pipeline 6 for directional screening. The sludge rotates at a high speed in the sludge quality selection device 3. The sludge with lower density, lighter quality, poorer sedimentation performance, and poorer flocculation performance overflows through the overflow port 303 and then is discharged into the external sludge storage tank through the fourth sludge discharge pipeline 9. The sludge with higher density, heavier quality, better sedimentation performance, and better flocculation performance sinks and returns to the integrated reaction and sedimentation device 1 through the bottom flow port 302 and the first reflux pipeline 8 to continue participating in the reaction. Thus, the sludge with poor quality and sedimentation performance in the reaction system is discharged from the reaction system, thereby increasing the concentration and quality of the activated sludge in the integrated reaction and sedimentation device 1, and further improving the efficiency and effect of sewage treatment.

[0059] In some embodiments, the sludge quality selection device 3 is a hydrocyclone. Such as Figure 2As shown in the figure, the hydrocyclone is an efficient separation device that uses a centrifugal force field to separate mixtures of different densities and can be used for concentration and dehydration. The sludge enters the hydrocyclone tangentially from the first inlet 301 and forms a downward rotating flow inside the hydrocyclone. Based on the different densities, particle sizes, weights, etc. of different components in the sludge, the rotational motion inside the hydrocyclone is divided into: outer vortex flow and inner vortex flow motion. The sludge with a larger density and mass in the sludge moves radially towards the wall surface under the action of centrifugal force and simultaneously moves downward to form an outer vortex flow, and separates from the lighter components with a smaller density in the sludge during this process, and finally is discharged from the underflow outlet. Affected by the uneven distribution of the radial pressure inside the hydrocyclone, a low-pressure area or even a vacuum area is formed at the central position. The lighter components with a smaller density in the sludge gradually break away from the outer vortex flow and migrate towards the central position, and the migration amount is larger the closer it is to the underflow outlet, so that the lighter components cannot be discharged from the underflow port 302. The lighter components perform an upward rotating motion to form an inner vortex flow and finally are discharged from the overflow port 303.

[0060] In some embodiments, the chemical dosing device 13 is connected to the first sludge discharge pipeline 4 through the chemical dosing pipeline 14 to add a flocculant to the sludge pre-concentration tank 2. During the sludge pre-concentration process, the pre-concentration situation is monitored, and whether to add a flocculant is determined according to the pre-concentration situation, thereby improving the pre-concentration effect.

[0061] In some embodiments, the backwashing device 11 is connected to the third sludge discharge pipeline 7 through the backwashing pipeline 12 to backwash the sludge quality selection device 3. During the long-term operation of the sludge quality selection device 3, sludge may remain in the sludge quality selection device 3 and block the underflow port 302, the first inlet 301, etc., thus affecting the concentration and screening effects. Therefore, the backwashing device 11 is provided to backwash the sludge quality selection device 3 regularly or irregularly to ensure the separation effect of the sludge quality selection device 3. When backwashing is required, the backwashing pipeline 12 and the backwashing device 11 are opened. The backwashing liquid (generally the sludge supernatant) in the backwashing device 11 enters the sludge quality selection device 3 from the underflow port 302 through the backwashing pipeline 12 and the third sludge discharge pipeline 7 to realize the backwashing of the sludge quality selection device 3. The backwashing time for each time is 30 minutes. After a backwashing is completed, if the sludge quality selection device 3 can continue to operate normally, the backwashing is closed. If there is still an abnormality, a backwashing is performed again.

[0062] Specifically, a central cylinder 202 is arranged in the sludge pre-concentration tank 2, and a second inlet 201 is arranged at the top inside the sludge pre-concentration tank 2. The central cylinder 202 is located below the second inlet 201. A baffle 203 is arranged on the outer side wall of the central cylinder 202, and the included angle between the baffle 203 and the central cylinder 202 is 30 - 60°. The gap between the baffle 203 and the side wall of the sludge pre-concentration tank 2 is 5 - 20 cm. The sludge enters the sludge pre-concentration tank 2 from the central cylinder 202 for sludge-water separation. The sludge settles at the bottom of the tank. After pre-concentrating for a certain period of time, it then enters the sludge quality selection device 3 through the pre-concentration sludge discharge pipeline 5 for further concentration. The upper clear liquid slowly rises from the edges through the two side baffles 203 and finally flows out through the pre-concentration water outlet pipeline 17. A lift pump can be arranged on the second sludge discharge pipeline 6 and the pre-concentration sludge discharge pipeline 5 to pressurize the sludge, so that the sludge enters the sludge quality selection device 3 at a higher pressure, thereby achieving better separation and concentration.

[0063] In some embodiments, a sludge concentration meter A1, a sludge level meter L1, and an online sludge sedimentation ratio detector SV are arranged in the integrated reaction sedimentation device 1 to detect the sludge concentration X1, the sludge level h1, and the sludge sedimentation ratio SV in the integrated reaction sedimentation device 1 respectively. A flow meter F1 is also provided to detect the influent flow rate Q1. The sludge pre-concentration tank 2 is provided with a sludge level meter L2 and a sludge concentration meter A2 to detect the sludge level h2 and the influent sludge concentration X2 in the sludge pre-concentration tank 2 respectively. The first inlet 301 of the sludge quality selection device 3 is provided with a sludge concentration meter A3, a pressure gauge P1, and a flow meter F2 to detect the sludge concentration X3, the pressure p1, and the flow rate Q2 at the first inlet 301 respectively. The underflow port 302 of the sludge quality selection device 3 is provided with a sludge concentration meter A4, a pressure gauge P2, and a flow meter F4 to detect the sludge concentration X4, the pressure p2, and the flow rate Q3 at the underflow port 302 respectively. The overflow port 303 is provided with a flow meter F3 to detect the flow rate Q3 at the overflow port. Through the above settings, the automatic control of the sludge concentration and quality selection system is realized.

[0064] The present application also provides a control method for a sludge concentration and quality selection system, which applies the sludge concentration and quality selection system of any of the above embodiments. The control method includes:

[0065] Monitoring the sludge concentration, sludge age, sludge sedimentation ratio, and reaction cycle during the sewage treatment process of the integrated reaction sedimentation device 1;

[0066] In response to the sludge concentration in the integrated reaction sedimentation device 1 being greater than the first concentration threshold or the sludge age being greater than the preset number of days, and the reaction cycle of the integrated reaction sedimentation device 1 being in the first preset cycle, starting the sludge concentration and quality selection system and operating it in the sludge concentration mode;

[0067] In response to the ratio of the sludge sedimentation ratio to the sludge concentration in the integrated reaction precipitation device 1 being greater than a first preset ratio or the sludge level being greater than a first preset height, and the reaction cycle being in a second preset cycle, start the sludge thickening and quality selection system and operate it in the sludge quality selection mode.

[0068] In this application, by monitoring the state of the sludge and the reaction cycle in the integrated reaction precipitation device 1, it is determined whether to start the sludge thickening and quality selection system and the operation mode of the sludge thickening and quality selection system, realizing the automatic intelligent control of the sludge thickening and quality selection system. When the sludge concentration in the integrated reaction precipitation device 1 is greater than a first concentration threshold or the sludge age is greater than a preset number of days, and the reaction cycle is in a first preset cycle, at this time, it is necessary to discharge the remaining sludge from the integrated reaction precipitation device 1, that is, start the sludge thickening and quality selection system and operate it in the sludge thickening mode. When the ratio of the sludge sedimentation ratio to the sludge concentration in the integrated reaction precipitation device 1 is greater than a first preset ratio or the sludge level therein is greater than a first preset height, and the reaction cycle is in a second preset cycle, it indicates that the sedimentation performance of the activated sludge in the integrated reaction precipitation device 1 is poor and the concentration is low at this time. Therefore, it is necessary to screen the sludge, and at this time, start the sludge thickening and quality selection system and operate it in the sludge quality selection mode. The start and operation of the sludge thickening and quality selection system are determined according to the state of the sludge and the reaction cycle in the integrated reaction precipitation device 1, making the operation of the system more in line with the actual needs of the integrated reaction precipitation device 1, capable of timely concentrating and discharging the activated sludge or performing cyclone screening, with higher intelligence, automation, processing efficiency, and a wider application range.

[0069] When the integrated reaction precipitation device 1 treats sewage, each treatment cycle sequentially includes the following four stages: the water inlet stage, the aeration stage, the static settlement stage, and the water outlet stage. In the water inlet stage, the sewage to be treated is introduced into the integrated reaction precipitation device 1; after the water inlet is completed, it enters the aeration stage, and aeration starts. Microorganisms in the activated sludge decompose and remove pollutants in the sewage; then it enters the static settlement stage, and solid substances settle to achieve solid-liquid separation; at this time, the supernatant in the integrated reaction precipitation device 1 is the treated sewage, and finally it enters the water outlet stage to discharge the supernatant from the reactor to the next treatment process, completing the treatment of the sewage to be treated. The activated sludge stays in the integrated reaction precipitation device 1 and continues to treat the next batch of sewage to be treated according to the process of water inlet - aeration - static settlement - water outlet. During the above process, that is, during the process of treating sewage using the integrated reaction precipitation device 1, the sludge concentration, sludge age, sludge sedimentation ratio, and reaction cycle in the integrated reaction precipitation device 1 are monitored, and the start and operation mode of the sludge thickening and quality selection system are determined according to the monitoring results.

[0070] Specifically, the first concentration threshold is 5000 mg / L, the preset number of days is 20 days, and the first preset cycle is the effluent stage. When the integrated reaction sedimentation device 1 is in the effluent stage, it is in a state after static sedimentation. The supernatant is discharged from the system to the next process. At this time, if it is monitored that the sludge concentration is greater than 5000 mg / L, it means that the sludge concentration in the integrated reaction sedimentation device 1 is too high at this time, and the separation of mud and water requires a longer time, thus affecting the sewage treatment efficiency. At the same time, as the sludge concentration increases, the oxygen consumption increases, the demand for aeration volume increases, and the treatment cost per unit of sewage increases. Therefore, at this time, the integrated reaction sedimentation device 1 can be concentrated and drained of sludge, that is, a part of the sludge is discharged from the integrated reaction sedimentation device 1 to reduce the sludge content in the integrated reaction sedimentation device 1, improve the sewage treatment efficiency, and reduce the cost.

[0071] During the long-term operation of the integrated reaction sedimentation device 1, when the sludge age reaches a certain duration, certain changes will occur in the sludge activity, the dominant microbial species, and the treatment performance in the sludge. Therefore, it is necessary to regularly drain the sludge, so as to always keep the activated sludge in the best treatment state. In this application, the preset number of days is set to 20 days. When the sludge age is greater than 20 days, the sludge concentration and quality selection system is started in the effluent stage of the integrated reaction sedimentation device 1 and operates in the sludge concentration mode, so as to perform concentrated sludge drainage. In addition, draining the sludge in the effluent stage will not affect the normal operation of the integrated reaction sedimentation device 1, and the operation efficiency is high. Optionally, the first concentration threshold can also be other values, such as 4800, 4500, 4200, 4000, 5200, 5500 mg / L, etc., which can be adjusted according to the specific characteristics of the activated sludge, the characteristics of the sewage to be treated, etc., and there is no specific limitation. The preset number of days can be 19, 18, 17, 16, 15, 12, 10, 8, 6, 5, 4, 22, 25, 26, 27, 28, 29, 30 days, which can be adjusted according to the specific characteristics of the activated sludge, the microbial species, the characteristics of the sewage to be treated, etc., and there is no specific limitation. Specifically, the first preset height is 4 / 5 of the liquid level of the integrated reaction sedimentation device 1. When the sludge level in the integrated reaction sedimentation device 1 is greater than 4 / 5 of the liquid level of the integrated reaction sedimentation device 1, it means that the sludge has expanded at this time and the sedimentation performance is poor. Therefore, it is necessary to start the sludge concentration and quality selection system to screen the sludge in the integrated reaction sedimentation device 1 and discharge the sludge with poor performance to improve the sludge performance, treatment efficiency and effect in the integrated reaction sedimentation device 1.

[0072] Specifically, the first preset ratio is 120, and the second preset period is the aeration stage. The sludge settling velocity (SV) is also known as the 30-minute sedimentation rate, which represents the percentage of the volume of the sedimented sludge formed after the mixed liquor is static for 30 minutes in the volume of the original mixed liquor. It can effectively reflect the amount of sludge and the coagulation and sedimentation performance of the sludge during normal aeration operation. The smaller the SV value, the better the sedimentation performance of the sludge. The occurrence of sludge bulking can be judged and detected through the change of the SV value. However, the SV value of the activated sludge is affected by the sludge concentration, and the two are positively correlated. Therefore, the SV value of the activated sludge can only roughly reflect the sedimentation performance of the sludge. When the sludge concentration also changes, the sludge settling ratio at this time cannot accurately reflect the structure and accurate sedimentation performance of the sludge. Therefore, in this application, the sludge settling ratio and the sludge concentration are used to determine the sedimentation performance of the sludge in the integrated reaction sedimentation device 1, which can avoid the influence of the sludge concentration on the sludge sedimentation. When the ratio of the sludge settling ratio to the sludge concentration is greater than 120, it indicates that the sedimentation performance of the sludge in the current integrated reaction sedimentation device 1 has deteriorated. Continuing to operate in this state is likely to cause the content of pollutants such as nitrogen and phosphorus in the final effluent to increase, the water quality to deteriorate, and the treatment effect to be affected. The concentration of the discharged sludge will also be relatively low. Therefore, at this time, the sludge concentration selection system is started and operated in the sludge selection mode to screen out the sludge with poor sedimentation performance and discharge it from the system, improve the sedimentation performance and quality of the sludge in the integrated reaction sedimentation device 1, and improve the sewage treatment effect and efficiency, so as to achieve efficient phosphorus and nitrogen removal.

[0073] In some embodiments, the sludge age is calculated by the following formula:

[0074]

[0075] where V is the effective tank volume of the integrated reaction sedimentation device 1, Q x is the sludge discharge amount per hour of the integrated reaction sedimentation device 1, X1 is the sludge concentration of the integrated reaction sedimentation device 1, and X2 is the inlet sludge concentration of the sludge pre-concentration tank 2.

[0076] In some embodiments, the operation steps of the sludge concentration mode include:

[0077] Start the sludge pre-concentration tank 2, and control the integrated reaction sedimentation device 1 to discharge sludge to the sludge pre-concentration tank 2 through the first sludge discharge pipeline 4;

[0078] Control the sludge to stay in the sludge pre-concentration tank 2 for a certain time for water separation and sedimentation, monitor the sludge level in the sludge pre-concentration tank 2 and the inlet sludge concentration of the sludge pre-concentration tank 2, and open the pre-concentrated water discharge pipeline 17 to discharge the upper clear liquid through the sludge pre-concentration tank 2;

[0079] In response to the sludge level in the sludge pre-concentration tank 2 being greater than or equal to the second preset height and the influent sludge concentration of the sludge pre-concentration tank 2 being greater than or equal to the second concentration threshold, start the sludge quality selection device 3 and control the sludge pre-concentration tank 2 to discharge sludge to the sludge quality selection device 3 through the pre-concentration sludge discharge pipeline 5 and the first inlet 301;

[0080] Use the sludge quality selection device 3 to separate and concentrate the sludge. The concentrated sludge is discharged into the external sludge storage tank through the underflow port 302 and the third sludge discharge pipeline 7, and the upper layer of the mud-water mixture flows back to the integrated reaction sedimentation device 1 through the overflow port 303 and the second return pipeline 10.

[0081] When the sludge thickening and quality selection system operates in the sludge thickening mode, the second sludge discharge pipeline 6, the first reflux pipeline 8, and the fourth sludge discharge pipeline 9 are in a non-enabled state. The specific operation of the sludge thickening mode is as follows: Start the sludge pre-thickening tank 2, and control the integrated reaction and sedimentation device 1 to discharge sludge to the sludge pre-thickening tank 2 through the first sludge discharge pipeline 4; The sludge enters the sludge pre-thickening tank 2 and stays for a certain time for sludge-water separation. The sludge gradually sinks to the bottom, and the supernatant liquid is discharged through the pre-thickened water outlet pipeline 17, thereby realizing the pre-thickening of the sludge. When the sludge stays in the sludge pre-thickening tank 2, monitor the sludge level in the sludge pre-thickening tank 2 and the inlet sludge concentration of the sludge pre-thickening tank 2; When the sludge level in the sludge pre-thickening tank 2 is greater than or equal to the second preset height, and the inlet sludge concentration of the sludge pre-thickening tank 2 is greater than or equal to the second concentration threshold, it indicates that the pre-thickening of the sludge has reached the target effect at this time. At this time, open the pre-thickened sludge discharge pipeline 5 and the sludge quality selection device 3, and pass the sludge in the sludge pre-thickening tank 2 into the sludge quality selection device 3 through the pre-thickened sludge discharge pipeline 5; The sludge rotates at a high speed in the sludge quality selection device 3, and the water and lighter sludge (i.e., the sludge-water mixture) in the sludge flow into the second reflux pipeline 10 through the overflow port 303, and thus return to the integrated reaction and sedimentation device 1, while the heavier sludge (i.e., the thickened sludge) sinks to the bottom and is discharged into the external sludge storage tank through the third sludge discharge pipeline 7 for subsequent treatment. At this time, the sludge entering the external sludge storage tank is thickened sludge, with high sludge concentration, low water content, high density, and small volume, which is not only convenient for transportation, but also can reduce the subsequent treatment process, reduce the floor area, energy consumption, etc., thereby realizing the efficient treatment of the surplus sludge. Specifically, usually, the sludge staying in the sludge pre-thickening tank 2 for 30 min to 90 min can achieve a good pre-thickening effect. Therefore, the residence time can be set to 30 min to 90 min, such as 35, 45, 50, 60, 70, 80 min, etc., or other values less than 30 min or greater than 90 min, which can be adjusted according to the actual situation, and there is no specific limit. Of course, it is also possible not to control the residence time, and only determine the opening of the pre-thickened sludge discharge pipeline 5 and the sludge quality selection device 3 based on the sludge level in the sludge pre-thickening tank 2 and the inlet sludge concentration of the sludge pre-thickening tank 2, and there is no specific limit.

[0082] Specifically, the second preset height is 2 / 3 of the liquid level of the sludge pre-thickening tank 2, and the second concentration threshold is 10,000 mg / L. When the sludge level in the sludge pre-thickening tank 2 is greater than or equal to 2 / 3 of the liquid level of the sludge pre-thickening tank 2, and the inlet sludge concentration of the sludge pre-thickening tank 2 is greater than or equal to 10,000 mg / L, it indicates that the sludge concentration in the sludge pre-thickening tank 2 is relatively high, and the purpose of pre-thickening is achieved. At this time, start the sludge quality selection device 3 again to effectively separate the heavier sludge from the lighter sludge and water, and complete the thickening of the sludge. At the same time, through the pre-thickening in the sludge pre-thickening tank 2, the thickening efficiency of the subsequent sludge quality selection device 3 can be greatly improved, and the efficient thickening of the sludge can be realized.

[0083] In some instances, the operating steps of the sludge concentration mode further include:

[0084] In response to the sludge staying in the sludge pre-concentration tank 2 for more than a preset time, the sludge level in the sludge pre-concentration tank 2 is still less than a second preset height, or the incoming sludge concentration of the sludge pre-concentration tank 2 is still less than a second concentration threshold, the dosing device 13 is activated to add a flocculant into the sludge pre-concentration tank 2.

[0085] When the sludge stays in the sludge pre-concentration tank 2 for more than a preset time, the sludge level in the sludge pre-concentration tank 2 is still less than a second preset height, or the incoming sludge concentration of the sludge pre-concentration tank 2 is still less than a second concentration threshold, at this time, the dosing device 13 is activated to add a flocculant into the sludge pre-concentration tank 2 to improve the sludge sedimentation effect of the sludge pre-concentration tank 2, so as to accelerate pre-concentration and improve the treatment efficiency. Specifically, the preset time can be 45 min, or can be set to less than 45 min, such as 40 min, 35 min, 30 min, etc., or greater than 45 min, such as 50 min, 55 min, 60 min, etc., and can be adjusted according to the actual operation conditions, and is not specifically limited.

[0086] In some embodiments, the addition dosage of the flocculant is calculated by the following formula: where C represents the addition dosage of the flocculant.

[0087] In some embodiments, the operating steps of the sludge quality selection mode include:

[0088] The sludge quality selection device 3 is activated, and the integrated reaction sedimentation device 1 is controlled to discharge sludge to the sludge quality selection device 3 through the second sludge discharge pipeline 6 and the first inlet 301;

[0089] The sludge quality selection device 3 is used to perform swirl screening on the discharged sludge, and the bottom sludge flows back to the integrated reaction sedimentation device 1 through the underflow port 302 and the first reflux pipeline 8; the upper-layer sludge is discharged into the external sludge storage tank through the overflow port 303 and the fourth sludge discharge pipeline 9.

[0090] When the sludge thickening and quality selection system operates in the sludge quality selection mode, the first sludge discharge pipeline 4, the sludge pre-thickening tank 2, the pre-thickening sludge discharge pipeline 5, the pre-thickening water outlet pipeline 17, the third sludge discharge pipeline 7 and the second return pipeline 10 are in a non-enabled state. The specific operation steps of the sludge quality selection mode are as follows: Start the sludge quality selection device 3, open the second sludge discharge pipeline 6, the first return pipeline 8 and the fourth sludge discharge pipeline 9, and then control the integrated reaction and sedimentation device 1 to discharge sludge into the sludge quality selection device 3 through the second sludge discharge pipeline 6 and the first inlet 301. The sludge rotates at a high speed in the sludge quality selection device 3. The sludge with a lower density, lighter mass, poorer sedimentation performance and poorer flocculation performance (i.e., the upper-layer sludge) floats up and is discharged into the external sludge storage tank through the overflow port 303 and the fourth sludge discharge pipeline 9, so that this part of the sludge with poor quality is completely discharged from the reaction system; the sludge with a higher density, heavier mass, better sedimentation performance and better flocculation performance sinks and returns to the integrated reaction and sedimentation device 1 through the underflow port 302 and the first return pipeline 8 to continue to participate in the reaction, thereby increasing the concentration and quality of the activated sludge in the integrated reaction and sedimentation device 1, and further improving the efficiency and effect of sewage treatment.

[0091] In some embodiments, it further includes:

[0092] During the operation of the sludge quality selection device 3, monitor the sludge concentration, flow rate and pressure of the underflow port 302 and the first inlet 301;

[0093] In response to the ratio of the sludge concentration at the underflow port 302 to that at the first inlet 301 being less than a second preset ratio, or the ratio of the flow rate at the underflow port 302 to that at the first inlet 301 being greater than a third preset ratio or less than a fourth preset ratio, or the pressure difference between the first inlet 301 and the underflow port 302 being greater than or equal to a preset difference, control the backwashing device 11 to open and backwash the sludge quality selection device 3 through the backwashing pipeline 12.

[0094] When operating in the sludge thickening mode, if the sludge quality selection device 3 malfunctions due to blockage or the like, the sludge concentration, flow rate, pressure, etc. at the underflow port 302 and the first inlet 301 of the sludge quality selection device 3 will change. Therefore, the opening of the backwashing device 11 can be controlled by the changes in the sludge concentration, flow rate, pressure, etc. at the underflow port 302 and the first inlet 301. When it is monitored that the sludge concentration ratio between the underflow port 302 and the first inlet 301 is less than the second preset ratio, or the flow rate ratio between the underflow port 302 and the first inlet 301 is greater than the third preset ratio or less than the fourth preset ratio, or the pressure difference between the first inlet 301 and the underflow port 302 is greater than or equal to the preset difference, it indicates that the sludge quality selection device 3 is operating abnormally and there may be a blockage. Therefore, the backwashing device 11 is activated to backwash the sludge quality selection device 3 through the backwashing pipeline 12 to clear the blockage, thereby ensuring the normal operation of the sludge quality selection device 3 and ensuring the efficient thickening and screening of the sludge. Specifically, the second preset ratio is 1.5, and it can also be set to other values according to the actual situation, such as 1.4, 1.3, 1.2, 1.6, 1.7, 1.8, 1.9, 2, 3, etc., without specific limitation; the third preset ratio is 0.5, and it can also be set to other values according to the actual situation, such as 0.4, 0.5, 0.6, 0.7, etc., without specific limitation; the preset difference is 0.1 Mpa, and it can also be set to other values according to the actual situation, such as 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, etc., without specific limitation; the fourth preset ratio is 0.2, and it can also be set to other values according to the actual situation, such as 0.1, 0.15, 0.25, 0.3, 0.4, etc., without specific limitation.

[0095] In some embodiments, the operation steps of the sludge quality selection mode further include:

[0096] Monitoring the sludge particle size in the integrated reaction sedimentation device 1;

[0097] After the sludge quality selection device 3 operates for the target cycle, the ratio of the sludge sedimentation ratio to the sludge concentration in the integrated reaction sedimentation device 1 is still greater than the first preset ratio;

[0098] Adding a microbial carrier to the integrated reaction sedimentation device 1 until the sludge particle size in the integrated reaction sedimentation device 1 meets the preset particle size value, or the ratio of the sludge sedimentation ratio to the sludge concentration is less than or equal to the preset ratio.

[0099] During the operation of the integrated reaction precipitation device 1, when the performance of the activated sludge therein deteriorates, the sludge quality selection device 3 can be started to operate in the sludge quality selection mode, so as to screen out the activated sludge with poor sedimentation performance and quality. However, after the sludge quality selection device 3 has been operating for a certain period, if the ratio of the sludge sedimentation ratio to the sludge concentration in the integrated reaction precipitation device 1 is still greater than the first preset ratio, it indicates that it is difficult to rapidly improve the sedimentation performance of the activated sludge solely relying on the sludge quality selection device 3. Therefore, at this time, a microbial carrier can be added to the integrated reaction precipitation device 1, so that pollutants, sludge, etc. in the sewage can polymerize with the microbial carrier into large particles of easily precipitable flocs, thereby accelerating the sedimentation of the sludge, and further effectively improving the performance of the activated sludge in the integrated reaction precipitation device 1, ensuring the sewage treatment efficiency and effect. Specifically, the microbial carrier includes carriers such as microsand and diatomite that are easy for organisms to adhere to, and the density of the microbial carrier is greater than 1 g / cm 3 . When the selected microbial carrier is microsand, the particle size of the microsand is 60 - 100 μm, and the dosage is 1% of the sludge concentration in the integrated reaction precipitation device 1, that is, 1%X1, and the evaluation index of the sludge particle size is D 50 . The preset particle size value is 100 μm, that is, when the sludge particle size D 50 > 100 μm or the ratio of the sludge sedimentation ratio to the sludge concentration is less than or equal to the first preset ratio, the addition of microsand can be stopped. Optionally, the sludge particle size can be monitored by an online particle size distribution monitor.

[0100] The target cycle of the sludge quality selection device 3 can be determined by the replacement cycle. The replacement cycle is the number of days required for the sludge quality selection device 3 to evenly screen all the activated sludge in the integrated reaction precipitation device 1 once. The replacement cycle can be calculated by the following formula:

[0101]

[0102] where n is the replacement cycle, X1 is the sludge concentration in the integrated reaction precipitation device 1, V is the effective tank volume of the integrated reaction precipitation device 1, Q2 is the flow rate of the first inlet 301 of the sludge quality selection device 3, and X3 is the sludge concentration of the first inlet 301 of the sludge quality selection device 3.

[0103] After calculating the replacement period, the target period can be 5 to 10 replacement periods, such as 5n, 6n, 7n, 8n, 9n, 10n. It can also be set to more than 10 replacement periods or less than 5 replacement periods, such as 4n, 3n, 2n, n, 11n, 12n, 13n, 14n, etc. It can be adjusted according to the actual operation situation, and there is no specific limitation. When starting the sludge quality selection device 3, calculate the replacement period, then determine the target period according to the replacement period, and then the sludge quality selection device 3 operates at the target period. When the target period is completed, if the ratio of the sludge sedimentation ratio to the sludge concentration in the integrated reaction sedimentation device 1 is still greater than the first preset ratio, at this time, microbial carriers can be added to the integrated reaction sedimentation device 1 to improve the sludge sedimentation performance of the integrated reaction sedimentation device 1.

[0104] The sludge concentration, sludge level, flow rate, and pressure in this application are the average values of continuously multiple measurements. In sewage treatment, the concentration, level, flow rate, pressure, etc. usually fluctuate with the influent and effluent conditions. Therefore, in this application, using the average value of continuously multiple measurements can more truly reflect the actual situation. Specifically, it can be the average value within 2, 3, 4, 5, 6, 7, 8, 9, 10 times, etc. of continuous measurements, or it can be other numbers of times, without specific limitation. Exemplarily, the concentration, level, flow rate, and pressure data can be read every 1 minute, and the data obtained continuously 3 times are averaged, which is the sludge concentration, sludge level, flow rate, and pressure data finally used for determination and calculation. The sludge sedimentation ratio is the sludge sedimentation ratio when the sludge has settled for 30 minutes.

[0105] This application also provides a sewage treatment system, as Figure 1 shown, including the integrated reaction sedimentation device 1 and the sludge thickening and quality selection system of any of the above embodiments, and further including:

[0106] An influent pipeline 15 and an effluent pipeline 16 respectively connected to the integrated reaction sedimentation device 1. The influent pipeline 15 is used to introduce the sewage to be treated into the integrated reaction sedimentation device 1, and the effluent pipeline 16 is used to discharge the treated sewage to the next process.

[0107] The sewage treatment system of this application includes an integrated reaction sedimentation device 1 and a sludge thickening and quality selection system. Active sludge is inoculated in the integrated reaction sedimentation device 1 to treat sewage. When it is necessary to thicken and discharge the sludge or screen the sludge in the integrated reaction sedimentation device 1, start the sludge thickening and quality selection system and operate in the corresponding operation mode, which can effectively improve the sludge and its concentration, and improve the subsequent sludge treatment efficiency and sewage treatment effect.

[0108] This application also provides a sewage treatment method, which is applied to the sewage treatment system of the above embodiment. The method includes:

[0109] The sewage to be treated is introduced into the integrated reaction and sedimentation device 1 inoculated with activated sludge through the influent pipeline 15, and the treated sewage is discharged to the next process through the effluent pipeline 16;

[0110] During the treatment process of the integrated reaction and sedimentation device 1, the sludge concentration and quality selection system is controlled by using the control method of the sludge concentration and quality selection system in any of the above embodiments, so as to concentrate or screen the sludge according to the state of the activated sludge in the integrated reaction and sedimentation device 1.

[0111] When it is necessary to start the integrated reaction and sedimentation device 1 for sewage treatment, the sewage to be treated is introduced into the integrated reaction and sedimentation device 1 inoculated with activated sludge through the influent pipeline 15. After passing through the aeration stage and the static stage in the integrated reaction and sedimentation device 1, it enters the effluent stage and is discharged from the integrated reaction and sedimentation device 1 through the effluent pipeline 16 to enter the next process.

[0112] The following uses a specific example to illustrate the effect of the present application.

[0113] A sequencing batch reactor is used as the integrated reaction and sedimentation device 1, and the sludge concentration and quality selection system of the present application is connected to the sequencing batch reactor to form a sewage treatment system, as Figure 1 shown.

[0114] The sequencing batch reactor has an outlet, an inlet, a sludge discharge port and a sludge inlet. The inlet of the sequencing batch reactor is connected to the influent pipeline 15, the outlet is connected to the effluent pipeline 16, the sludge discharge port is connected to the second inlet 201 of the sludge pre-concentration tank 2 through the first sludge discharge pipeline 4, and the sludge discharge port is connected to the first inlet 301 of the sludge quality selection device 3 through the second sludge discharge pipeline 6.

[0115] The sludge pre-concentration tank 2 is provided with a second inlet 201 at the top and a central cylinder 202 inside. The central cylinder 202 is located below the second inlet 201. A baffle 203 is provided on the outer side wall of the central cylinder 202, and the included angle between the baffle 203 and the central cylinder 202 is 30-60°. The gap between the baffle 203 and the side wall of the sludge pre-concentration tank 2 is 5-20 cm. The upper part of the sludge pre-concentration tank 2 is connected with a pre-concentrated effluent pipeline 17 for discharging the upper clear liquid, and the bottom is connected to the first inlet 301 of the sludge quality selection device 3 through the pre-concentrated sludge discharge pipeline 5. In order to save costs and make reasonable use of each pipeline, the pre-concentrated sludge discharge pipeline 5 can be connected to the first sludge discharge pipeline 4 to realize the connection with the sludge quality selection device 3 by borrowing the first sludge discharge pipeline 4.

[0116] The sludge quality selection device 3 is a hydrocyclone device, with a first inlet 301 provided on the side wall, an underflow port 302 provided at the bottom, and an overflow port 303 provided at the top; the underflow port 302 is communicated with the sludge inlet of the sequencing batch sewage reactor through a first return pipeline 8 and is communicated with an external sludge storage tank through a third sludge discharge pipeline 7; the overflow port 303 is communicated with the water inlet of the sequencing batch sewage reactor through a second return pipeline 10 and is communicated with an external sludge storage tank through a fourth sludge discharge pipeline 9.

[0117] The chemical dosing device 13 is arranged to be communicated with the second inlet 201 of the sludge pre-concentration tank 2 through a chemical dosing pipeline 14. Optionally, the chemical dosing pipeline 14 can be connected to the first sludge discharge pipeline 4. While discharging sludge into the sludge pre-concentration tank through the first sludge discharge pipeline 4, the chemical agent can be introduced into the sludge pre-concentration tank, enabling uniform mixing of the chemical agent.

[0118] The backwashing device 11 is communicated with the third sludge discharge pipeline 7 through a backwashing pipeline 12. Valves are provided on the first sludge discharge pipeline 4, the pre-concentration sludge discharge pipeline 5, the pre-concentration water outlet pipeline 17, the second sludge discharge pipeline 6, the third sludge discharge pipeline 7, the first return pipeline 8, the fourth sludge discharge pipeline 9, the second return pipeline 10, the water inlet pipeline 15, and the water outlet pipeline 16 to control the enabling and closing of the pipelines. Optionally, the valves are electric valves.

[0119] A flow meter F1 is provided at the water inlet of the sequencing batch sewage reactor to detect the influent flow rate Q1. A sludge concentration meter A1, a sludge level meter L1, and an online sludge settling ratio detector SV are arranged inside to detect the sludge concentration X1, the sludge level h1, and the sludge settling ratio SV in the integrated reaction sedimentation device 1 respectively. A sludge concentration meter A2 is provided at the first inlet 301 of the sludge pre-concentration tank 2 to detect the influent sludge concentration X2, and a sludge level meter L2 is arranged inside to detect the sludge level h2 in the sludge pre-concentration tank 2; a sludge concentration meter A3, a pressure gauge P1, and a flow meter F2 are provided at the first inlet 301 of the sludge quality selection device 3 to detect the sludge concentration X3, the pressure p1, and the flow rate Q2 at the first inlet 301 respectively; a sludge concentration meter A4, a pressure gauge P2, and a flow meter F4 are provided at the underflow port 302 of the sludge quality selection device 3 to detect the sludge concentration X4, the pressure p2, and the flow rate Q3 at the underflow port 302 respectively; a flow meter F3 is provided at the overflow port 303 to detect the flow rate Q3 at the overflow port.

[0120] Each reaction cycle of the sequencing batch sewage reactor includes an influent stage, an aeration stage, a settling stage, and an effluent stage. The total reaction time for each reaction cycle is 240 min, denoted as \(T\). The influent stage is \(0\ min < T < 20\ min\), the aeration stage is \(20\ min < T < 180\ min\), the settling stage is \(180\ min < T < 220\ min\), and the effluent stage is \(220\ min < T < 240\ min\). The sequencing batch sewage reactor undergoes 6 reaction cycles per day, that is, it treats 6 batches of sewage. The number of reaction cycles of the sequencing batch sewage reactor and the division of the reaction time of each stage in each reaction cycle can be set according to the actual situation of the sewage to be treated, the water quality, the effluent requirements, etc., without specific restrictions.

[0121] Start the sequencing batch sewage reactor inoculated with activated sludge, and introduce the sewage to be treated into it through a water pipeline during the influent stage. During this process, monitor the sludge concentration \(X1\), sludge retention time \(SRT\), sludge volume index \(SV\), and reaction cycle of the sequencing batch sewage reactor. When it is detected that \(X1>5000\ mg / L\) or \(SRT = 20\) days, and at this time the reaction cycle in the sequencing batch sewage reactor is the effluent stage (\(220\ min < T < 240\ min\)), start the sludge thickening quality selection system and operate it in the sludge thickening mode.

[0122] The specific operation steps of the sludge thickening mode are as follows: (1) Start the sludge pre-thickening tank 2. The second sludge discharge pipeline 6 is in a closed state. Open the valves of the sludge discharge port of the sequencing batch reactor and the first sludge discharge pipeline 4, and discharge part of the sludge in the sequencing batch reactor into the sludge pre-thickening tank 2. The sludge enters the central cylinder 202 through the second inlet 201 and then enters the sludge pre-thickening tank 2 and stays for a certain period of time. Under this hydraulic condition, the sludge deposits at the bottom of the sludge pre-thickening tank 2, and the supernatant overflows through the gap between the baffle 203 and the pool wall and is discharged through the pre-thickened water discharge pipeline 17, thus achieving pre-thickening. When the sludge level h2 in the sludge pre-thickening tank 2 is greater than or equal to 2 / 3 of the liquid level (H2) of the sludge pre-thickening tank 2, that is, h2≥2 / 3H2 and the influent sludge concentration X2 in the sludge pre-thickening tank 2 is greater than or equal to 10,000 mg / L, that is, X2≥10,000 mg / L, it indicates that the sludge concentration in the sludge pre-thickening tank 2 is relatively high and the purpose of pre-thickening is achieved. At this time, start the sludge quality selection device 3 for sludge thickening. Close the first return pipeline 8 and the fourth sludge discharge pipeline 9, open the pre-thickened sludge discharge pipeline 5, the sludge quality selection device 3, the third sludge discharge pipeline 7 and the second return pipeline 10, and discharge the sludge in the sludge pre-thickening tank into the sludge quality selection device 3 through the pre-thickened sludge discharge pipeline 5. The sludge rotates at a high speed in the sludge quality selection device 3. The heavier sludge sinks to the bottom and is discharged into the external sludge storage tank through the underflow port 302 and the third sludge discharge pipeline 7. The lighter sludge and water overflow through the overflow port 303 and are returned to the sequencing batch reactor through the second sludge discharge pipeline 6. When the sludge level h2 in the sludge pre-thickening tank 2 is still less than 2 / 3 of the liquid level (H2) of the sludge pre-thickening tank 2 within the preset time, that is, h2<2 / 3H2, or the influent sludge concentration X2 in the sludge pre-thickening tank 2 is still less than 10,000 mg / L, that is, X2<10,000 mg / L, start the dosing device 13, open the dosing pipeline 14, and add flocculant to the sludge pre-thickening tank 2. Under the action of the flocculant, the sludge in the sludge pre-thickening tank 2 accelerates precipitation, achieving the pre-thickening effect.

[0123] During the reaction process of the sequencing batch reactor, when the ratio of the sludge sedimentation ratio SV to the sludge concentration X1 in the aeration stage of the sequencing batch reactor is greater than the first preset ratio, that is, SV / X1>120, or the sludge level h1 in the sequencing batch reactor is greater than 4 / 5 of the liquid level H1 of the sequencing batch reactor, that is, h1>4 / 5H1, and the reaction cycle in the sequencing batch reactor is the aeration stage (20 min < T < 180 min), start the sludge thickening quality selection system and operate in the sludge quality selection mode.

[0124] The operation steps of the sludge quality selection mode are as follows: Start the sludge quality selection device 3, open the second sludge discharge pipeline 6, and close the first sludge discharge pipeline 4, the sludge pre-concentration tank 2, the pre-concentration sludge discharge pipeline 5, the second reflux pipeline 10, and the third sludge discharge pipeline 7. Part of the sludge in the sequencing batch reactor is introduced into the sludge quality selection device 3 through the second sludge discharge pipeline 6 and the first inlet 301. The sludge rotates at a high speed in the sludge quality selection device 3. The sludge with poor quality and poor sedimentation performance overflows through the overflow port 303 and is discharged to the external sludge storage tank through the fourth sludge discharge pipeline 9. The sludge with heavier mass and good sedimentation performance sinks to the bottom and flows into the first reflux pipeline 8 through the underflow port 302, and then is re-circulated to the sequencing batch reactor through the inlet, realizing the screening of high-quality and high-sedimentation-performance sludge. During this process, continuously monitor the sludge particle size D in the sequencing batch reactor. 50 After the sludge quality selection device 3 operates for the target cycle, that is, after operating for 10 replacement cycles, if the ratio of the sludge sedimentation ratio to the sludge concentration in the sequencing batch reactor is still greater than the first preset ratio, that is, SV / X1 > 120, add fine sand to the sequencing batch reactor until the sludge particle size D in the sequencing batch reactor 50 meets the preset particle size value, that is, D 50 > 100 μm, or the ratio of the sludge sedimentation ratio to the sludge concentration is less than or equal to the preset ratio, that is, SV / X1 ≤ 120, stop adding fine sand.

[0125] During the operation of the sludge quality selection device 3, monitor the sludge concentration X4, flow rate Q4, and pressure p2 at the underflow port 302, and monitor the sludge concentration X3, flow rate Q2, and pressure p1 at the first inlet 301; when X4 / X3 < 1.5 or Q4 / Q2 > 0.5 or Q4 / Q2 < 0.2 or p1 - p2 ≥ 0.1 Mpa, it indicates that there is a certain abnormality in the sludge quality selection device 3 and the operation efficiency is reduced. Control the backwashing device 11 to start, and backwash the sludge quality selection device 3 through the backwashing pipeline 12. Q2 and Q4 are measured by flow meters F2 and F4 respectively, X1, X2, X3, and X4 are measured by sludge concentration meters A1, A2, A3, and A4 respectively; h1 and h2 are measured by sludge level meters L1 and L2 respectively, and p1 and p2 are measured by pressure gauges P1 and P2 respectively.

[0126] In the sequencing batch reactor, after the static settling stage, open the water outlet pipeline 16 and the water outlet, and discharge the treated sewage to the next process to complete the treatment of a batch of sewage. After the drainage is completed, then open the water inlet and the water inlet pipeline 15, and introduce the next batch of sewage to be treated, and repeat the above process to continue the sewage treatment. Using the present application to treat the excess sludge in the sequencing batch reactor can reduce the floor area for excess sludge dewatering, with the floor area saved > 30%, and the treatment efficiency is high. The concentrated sludge is easier to dewater (property improvement), saving chemicals; at the same time, it can effectively improve the sludge sedimentation performance, with in-situ capacity expansion > 30%.

[0127] The technical effects of the present application will be further described below through embodiments.

[0128] Embodiment 1:

[0129] A certain sewage treatment plant with a scale of 10,000 m 3 / d and using the SBR core process had problems such as a relatively low concentration of excess sludge, a large floor area of the sludge storage tank without additional land, poor thickening effect, and the moisture content of dewatered sludge not meeting the requirements for external transportation before adopting the system of the present application. After the sewage treatment plant adopted the sludge thickening and quality selection system and the control method after the sludge thickening and quality selection system in the present invention, the scale of the sludge quality selection device was 50 m 3 / h, where the residence time of the sludge pre-thickening tank 2 was 1.5 h, the residence time of the sludge quality selection device 3 was 15 - 30 s, the flow rate of the bottom flow port 302 accounted for 40% - 45% of the flow rate of the first inlet 301, the sludge discharge concentration was concentrated from the original 3000 - 5000 mg / L to 10000 - 12000 mg / L, and the floor area of the sludge storage tank was saved by more than 1.5 times.

[0130] Embodiment 2:

[0131] CASS is a process that integrates reaction, sedimentation, drainage, and functions, and is realized by using the integrated reaction and sedimentation device 1. A certain sewage treatment plant with a scale of 5000 m 3 / d and using CASS as the core process also had the problem of poor sludge thickening effect before adopting the system. On the one hand, it affected the treatment and disposal of excess sludge, and on the other hand, it affected the reflux efficiency of the external reflux sludge. After the sewage treatment plant adopted the sludge thickening and quality selection system and the control method after the sludge thickening and quality selection system in the present invention, the scale of the sludge quality selection device was 25 m 3 / h, where the residence time of the sludge pre-thickening tank 2 was 1 h, the residence time of the sludge quality selection device 3 was 10 - 15 s, the flow rate of the bottom flow port 302 accounted for 30% - 35% of the flow rate of the first inlet 301, the sludge discharge concentration was concentrated from the original 4000 - 5000 mg / L to about 10000 mg / L, greatly reducing the floor area of the sludge storage tank, the dewatering efficiency of excess sludge, and the external reflux efficiency of the thickened sludge, etc.

[0132] Based on the same inventive concept, corresponding to the method of any of the above embodiments, the present application also provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, it implements the control method of the sludge thickening and quality selection system described in any of the above embodiments.

[0133] Figure 3FIG. 0 shows a more specific schematic diagram of the hardware structure of the electronic device provided in this embodiment. The device may include: a processor 1010, a memory 1020, an input / output interface 1030, a communication interface 1040, and a bus 1050. Among them, the processor 1010, the memory 1020, the input / output interface 1030, and the communication interface 1040 are communicatively connected to each other inside the device through the bus 1050.

[0134] The processor 1010 may be implemented in a general-purpose CPU (Central Processing Unit), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits, etc., and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this specification.

[0135] The memory 1020 may be implemented in the form of a ROM (Read Only Memory), a RAM (Random Access Memory), a static storage device, a dynamic storage device, etc. The memory 1020 may store an operating system and other application programs. When implementing the technical solutions provided in the embodiments of this specification through software or firmware, the relevant program codes are stored in the memory 1020 and are called and executed by the processor 1010.

[0136] The input / output interface 1030 is used to connect to an input / output module to implement information input and output. The input / output module may be configured as a component in the device (not shown in the figure) or externally connected to the device to provide corresponding functions. Among them, the input device may include a keyboard, a mouse, a touch screen, a microphone, various sensors, etc., and the output device may include a display, a speaker, a vibrator, an indicator light, etc.

[0137] The communication interface 1040 is used to connect to a communication module (not shown in the figure) to implement communication interaction between this device and other devices. Among them, the communication module may implement communication in a wired manner (such as USB, network cable, etc.) or in a wireless manner (such as mobile network, WIFI, Bluetooth, etc.).

[0138] The bus 1050 includes a path for transmitting information between various components of the device (such as the processor 1010, the memory 1020, the input / output interface 1030, and the communication interface 1040).

[0139] It should be noted that although the above device only shows the processor 1010, the memory 1020, the input / output interface 1030, the communication interface 1040, and the bus 1050, in the specific implementation process, the device may also include other components necessary for normal operation. In addition, those skilled in the art can understand that the above device may also only include the components necessary to implement the solution of the embodiment of the present specification, and does not necessarily include all the components shown in the figure.

[0140] The electronic device of the above embodiment is used to implement the control method of the corresponding sludge thickening quality selection system in any of the foregoing embodiments, and has the beneficial effects of the corresponding method embodiments, which will not be elaborated here.

[0141] Based on the same inventive concept, corresponding to the method of any of the above embodiments, the present application also provides a non-transitory computer-readable storage medium. The non-transitory computer-readable storage medium stores computer instructions, and the computer instructions are used to cause the computer to execute the control method of the sludge thickening quality selection system as described in any of the foregoing embodiments.

[0142] The computer-readable medium of this embodiment includes permanent and non-permanent, removable and non-removable media, and information storage can be implemented by any method or technology. The information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassette tapes, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible by a computing device.

[0143] The computer instructions stored in the storage medium of the above embodiment are used to cause the computer to execute the control method of the sludge thickening quality selection system as described in any of the foregoing embodiments, and have the beneficial effects of the corresponding method embodiments, which will not be elaborated here.

[0144] Those of ordinary skill in the art should understand that the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of the present application (including the claims) is limited to these examples; under the concept of the present application, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of the embodiments of the present application as described above, which are not provided in detail for the sake of brevity.

[0145] In addition, in cases where details have been set forth to describe exemplary embodiments of the present application, it will be apparent to those skilled in the art that the embodiments of the present application can be implemented without these details or with variations of these details. Therefore, these descriptions should be considered illustrative rather than restrictive.

[0146] For simplicity of explanation and discussion, and in order not to make the embodiments of the present application difficult to understand, well-known power / ground connections to other components may or may not be shown in the accompanying drawings. In addition, the devices may be shown in block diagram form in order not to make the embodiments of the present application difficult to understand, and this also takes into account the fact that details regarding the implementation of these block diagram devices are highly dependent on the platform on which the embodiments of the present application are to be implemented (i.e., these details should be entirely within the understanding of those skilled in the art). In cases where specific details have been set forth to describe exemplary embodiments of the present application, it will be apparent to those skilled in the art that the embodiments of the present application can be implemented without these specific details or with variations of these specific details. Therefore, these descriptions should be considered illustrative rather than restrictive.

[0147] Although the present application has been described in connection with specific embodiments of the present application, many alternatives, modifications, and variations of these embodiments will be apparent to those of ordinary skill in the art based on the foregoing description. For example, other memory architectures (e.g., dynamic RAM (DRAM)) may be used with the embodiments discussed.

[0148] The embodiments of the present application are intended to cover all such alternatives, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of the present application shall be included within the protection scope of the present application.

Claims

1. A sludge concentration and quality selection system, characterized in that: Applicable to integrated reaction sedimentation device inoculated with activated sludge; The sludge concentration and quality selection system is used to receive the sludge discharged from the integrated reaction and precipitation device and to concentrate or screen the sludge, including: A sludge pre-concentration tank, used for pre-concentrating the sludge by separating the sludge from the water, connected to the integrated reaction sedimentation device through a first sludge discharge pipeline, and connected to a pre-concentration effluent pipeline for discharging the supernatant liquid from the sludge pre-concentration tank at the upper part; A sludge quality selection device, used for mud-water separation and concentration or cyclone screening of sludge, with a first inlet provided on the side wall, an underflow port provided on the bottom, and an overflow port provided on the top, wherein the first inlet is connected to the integrated reaction sedimentation device and the sludge pre-concentration tank through the second mud discharge pipeline and the pre-concentration mud discharge pipeline respectively; the underflow port is connected to the integrated reaction sedimentation device and the external mud storage tank through the first return pipeline and the third mud discharge pipeline respectively; the overflow port is connected to the integrated reaction sedimentation device and the external mud storage tank through the second return pipeline and the fourth mud discharge pipeline respectively; The sludge concentration and quality selection system has at least two working modes including a sludge quality selection mode and a sludge concentration mode; in the sludge quality selection mode, the first sludge discharge pipeline, the sludge pre-concentration tank, the pre-concentration sludge discharge pipeline, the pre-concentration effluent pipeline, the third sludge discharge pipeline and the second return pipeline are in an inactive state; in the sludge concentration mode, the second sludge discharge pipeline, the first return pipeline and the fourth sludge discharge pipeline are in an inactive state.

2. The sludge concentration and quality selection system according to claim 1, characterized in that: Also includes: a dosing device, connected to the first sludge discharge pipeline via a dosing pipeline, for adding flocculants into the sludge pre-thickening tank; And / or, a backwashing device is connected to the third sludge discharge pipeline through a backwashing pipeline to backwash the sludge selection device.

3. A control method for a sludge concentration and quality selection system, characterized in that: Applicable to the sludge concentration and quality separation system according to any one of claims 1 to 2; the control method comprises: Monitoring the sludge concentration, sludge age, sludge settling ratio, sludge level and reaction cycle during the sewage treatment process of the integrated reaction sedimentation device; In response to the sludge concentration in the integrated reaction and precipitation device being greater than a first concentration threshold or the sludge age being greater than a preset number of days, and the reaction cycle of the integrated reaction and precipitation device being in a first preset cycle, starting the sludge concentration and quality selection system and operating it in the sludge concentration mode; In response to the ratio of the sludge settling ratio to the sludge concentration in the integrated reaction sedimentation device being greater than the first preset ratio or the sludge level being greater than the first preset height, and the reaction cycle being in the second preset cycle, the sludge concentration and quality selection system is started and operated in the sludge quality selection mode.

4. The control method of a sludge concentration and quality selection system according to claim 3 is characterized in that: The operation steps of the sludge concentration mode include: Starting the sludge pre-concentration tank, and controlling the integrated reaction sedimentation device to discharge sludge into the sludge pre-concentration tank through the first sludge discharge pipeline; Controlling the sludge to stay in the sludge pre-concentration tank for a certain period of time to separate from water and precipitate, monitoring the sludge level in the sludge pre-concentration tank and the sludge concentration of the sludge pre-concentration tank, and opening the pre-concentration effluent pipeline to discharge the supernatant through the sludge pre-concentration tank; In response to the sludge level in the sludge pre-concentration tank being greater than or equal to a second preset height and the sludge concentration of the sludge inlet of the sludge pre-concentration tank being greater than or equal to a second concentration threshold, starting the sludge quality selection device, and controlling the sludge pre-concentration tank to discharge sludge to the sludge quality selection device through the pre-concentration sludge discharge pipeline and the first inlet; The sludge quality selection device is used to separate and concentrate the sludge from water. The concentrated sludge is discharged into an external sludge storage tank through the bottom flow port and the third sludge discharge pipeline, and the upper layer of sludge and water mixture is returned to the integrated reaction sedimentation device through the overflow port and the second return pipeline.

5. The control method of a sludge concentration and quality selection system according to claim 4 is characterized in that: The operation steps of the sludge concentration mode also include: In response to the sludge staying in the sludge pre-concentration tank for more than a preset time, the sludge level in the sludge pre-concentration tank is still less than a second preset height, or the sludge concentration of the sludge pre-concentration tank is still less than a second concentration threshold, the dosing device is started to add flocculant to the sludge pre-concentration tank.

6. The control method of a sludge concentration and quality selection system according to claim 4 is characterized in that: The operation steps of the sludge quality selection mode include: Starting the sludge quality selection device, and controlling the integrated reaction sedimentation device to discharge sludge to the sludge quality selection device through the second sludge discharge pipeline and the first inlet; The sludge quality selection device is used to perform cyclone screening on the discharged sludge, and the bottom sludge is returned to the integrated reaction sedimentation device through the bottom flow port and the first return pipeline; the upper sludge is discharged into the external sludge storage tank through the overflow port and the fourth sludge discharge pipeline.

7. The control method of a sludge concentration and quality selection system according to claim 6 is characterized in that: Also includes: During the operation of the sludge quality selection device, monitoring the sludge concentration, flow rate and pressure of the underflow port and the first inlet; In response to the sludge concentration ratio of the underflow port to the first inlet being less than the second preset ratio, or the flow ratio of the underflow port to the first inlet being greater than the third preset ratio or less than the fourth preset ratio, or the pressure difference between the first inlet and the underflow port being greater than or equal to the preset difference, the backwash device is controlled to open, and the sludge quality selection device is backwashed through the backwash pipeline.

8. According to the control method of a sludge concentration and quality selection system according to claim 6, the operation steps of the sludge quality selection mode further include: Monitoring the sludge particle size in the integrated reaction-precipitation device; After the sludge quality selection device runs for a target period, the ratio of the sludge settling ratio to the sludge concentration in the integrated reaction sedimentation device is still greater than the first preset ratio; A microbial carrier is added to the integrated reaction precipitation device until the sludge particle size in the integrated reaction precipitation device meets a preset particle size value, or the ratio of the sludge settling ratio to the sludge concentration is less than or equal to a preset ratio.

9. A sewage treatment system, characterized in that: The invention comprises an integrated reaction precipitation device and the sludge concentration and quality separation system according to any one of claims 1 to 2, and further comprises: An inlet pipeline and an outlet pipeline are respectively connected to the integrated reaction precipitation device, wherein the inlet pipeline is used to pass the sewage to be treated into the integrated reaction precipitation device, and the outlet pipeline is used to discharge the treated sewage to the next process.

10. A method for treating sewage, characterized in that: Applied to a sewage treatment system as claimed in claim 9, the method comprising: The sewage to be treated is introduced into the integrated reaction sedimentation device inoculated with activated sludge through an inlet pipeline, and the treated sewage is discharged to the next process through an outlet pipeline; During the treatment process of the integrated reaction sedimentation device, the sludge concentration and quality selection system is controlled by the control method of the sludge concentration and quality selection system described in any one of claims 3 to 8, so as to concentrate or screen the sludge according to the state of the activated sludge in the integrated reaction sedimentation device.

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