A sewage treatment system and method using side stream sludge thermal hydrolysis coupled with heat pump waste heat

Abstract

The present invention relates to the field of sewage treatment technology, and in particular to a sewage treatment system and method for side-stream sludge thermal hydrolysis coupled with heat pump waste heat, comprising a biochemical tank, a secondary sedimentation tank, a side-stream tank, a thermal hydrolysis module and a water source heat pump module, wherein the heat energy collection end of the water source heat pump module is connected to the secondary sedimentation tank, the heat energy output end of the water source heat pump module is connected to the thermal hydrolysis module, the solid phase output end of the secondary sedimentation tank is connected to the thermal hydrolysis module via a side-stream pipeline, and the thermal hydrolysis module is connected to the biochemical tank via the side-stream tank. In this application, the water source heat pump module extracts heat from the sewage flowing out of the secondary sedimentation tank, and after improving the thermal energy grade, provides stable reaction temperature conditions for the thermal hydrolysis reaction of the sludge in the thermal hydrolysis module, realizes the synergy of sludge thermal hydrolysis technology and side-stream process, effectively reduces the energy consumption of the thermal hydrolysis reaction, reduces the cost of supplying the temperature conditions for the thermal hydrolysis reaction, improves energy utilization, and realizes low-carbon operation.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and in particular to a sewage treatment system and method using side stream sludge thermal hydrolysis coupled with heat pump waste heat. Background Art

[0002] Traditional activated sludge wastewater treatment systems typically include a biochemical reactor and a secondary sedimentation tank. The biochemical reactor is used for microbial treatment of wastewater, while the secondary sedimentation tank is used for sludge-water separation. To reduce the sludge load in the mainstream system, in addition to directly returning the sludge from the secondary sedimentation tank to the biochemical reactor, a sidestream process is typically used to separately treat some of the returned sludge (e.g., anaerobic digestion, bioaugmentation, etc.). However, in the process of implementing the present invention, the applicant discovered that, in the absence of reliance on external energy sources, the existing technology suffers from insufficient sludge carbon source release in the sidestream process, failing to meet the requirements of mainstream denitrification and requiring the addition of an additional carbon source. Summary of the Invention

[0003] The purpose of the present invention is to provide a sewage treatment system and method using side stream sludge thermal hydrolysis coupled with heat pump waste heat to solve the above technical problems existing in the prior art, mainly including the following two aspects:

[0004] In the first aspect, a sewage treatment system of side-stream sludge thermal hydrolysis coupled with heat pump waste heat is disclosed, comprising a biochemical tank, a secondary sedimentation tank, a side-stream tank, a thermal hydrolysis module, a preheating module and a water source heat pump module. The biochemical tank and the secondary sedimentation tank are arranged in sequence along the sewage flow direction. The heat energy collection end of the water source heat pump module is connected to the liquid phase output end of the secondary sedimentation tank, and the heat energy output end of the water source heat pump module is connected to the thermal hydrolysis module. The water source heat pump module is used to collect the thermal energy of the liquid phase fluid in the liquid phase output end of the secondary sedimentation tank, and output it to the thermal hydrolysis module after improving the thermal energy grade, so as to realize the thermal hydrolysis treatment of the sludge by the thermal hydrolysis module. The solid phase output end of the secondary sedimentation tank is connected to the input end of the thermal hydrolysis module through a side-stream pipeline, and the output end of the thermal hydrolysis module is connected to the biochemical tank through the side-stream tank. The thermal hydrolysis module is connected, and is used to perform thermal hydrolysis treatment on the sludge flowing through it; the preheating module includes a gas circulation pipeline and a heat exchange component arranged in the gas circulation pipeline, the heat exchange component is arranged at the input end of the thermal hydrolysis module, and is used to preheat the sludge entering the thermal hydrolysis module, the thermal hydrolysis module includes a reaction chamber, the input end of the gas circulation pipeline is connected to the top of the reaction chamber, the output end of the gas circulation pipeline is arranged in the middle of the reaction chamber, and a circulation pump is provided on the gas circulation pipeline; the heat exchange component includes an outer sleeve arranged on the input end pipeline of the thermal hydrolysis module, and a preheating air channel is provided between the outer sleeve and the input end pipeline of the thermal hydrolysis module, and the preheating air channel is used to constitute a gas circulation pipeline to realize preheating of the sludge in the input end pipeline of the thermal hydrolysis module.

[0005] In a second aspect, a sewage treatment method is disclosed, which uses the above-mentioned sewage treatment system to treat sewage.

[0006] The technical solution adopted by the present invention can achieve the following beneficial effects:

[0007] In this application, the water source heat pump module extracts heat from the sewage flowing out of the secondary sedimentation tank, and after improving the thermal energy quality, the heat exchange medium is then sent to the thermal hydrolysis module to provide stable reaction temperature conditions for the thermal hydrolysis reaction of the sludge in the thermal hydrolysis module, thereby realizing the synergy of the sludge thermal hydrolysis technology and the side stream process. Compared with the prior art in which a heat source is separately configured to provide reaction temperature conditions for the thermal hydrolysis module, the energy consumption of the thermal hydrolysis reaction is effectively reduced, the cost of supplying the thermal hydrolysis reaction temperature conditions is reduced, the energy utilization rate is improved, and low-carbon operation is achieved;

[0008] In addition, the hot air in the thermal hydrolysis module is used to preheat the sludge that is about to undergo thermal hydrolysis, which can not only improve the thermal energy utilization rate, but also avoid local overheating of the sludge inside the thermal hydrolysis module by controlling and adjusting the gas phase in the thermal hydrolysis module, thereby affecting the thermal hydrolysis effect of the sludge. Auxiliary adjustment of the two dimensions of thermal hydrolysis reaction temperature conditions and reaction pressure conditions is achieved, which promotes the uniform and efficient thermal hydrolysis reaction inside the sludge. On the basis of improving the temperature stability of the thermal hydrolysis reaction inside the sludge, the utilization efficiency of the thermal energy resources of the thermal hydrolysis module is further improved, the energy efficiency of the thermal hydrolysis module and the sewage treatment system is improved, and the system operating cost is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0010] Figure 1 It is a structural schematic diagram of the sewage treatment system of the present invention;

[0011] Figure 2 Schematic diagram of the pipe connection of the sewage treatment system of the present invention;

[0012] Figure 3 Schematic diagram of the internal structure of the thermal hydrolysis module of the present invention;

[0013] Figure 4 Schematic diagram of the piping connection of the thermal hydrolysis module of the present invention;

[0014] Figure 5 Schematic diagram of the structure of the stirring shaft and stirring blades of the present invention;

[0015] Figure 6 It is a connection diagram of the control module and the temperature detection unit of the present invention.

[0016] In the picture:

[0017] 10. Biochemical pool; 20. Secondary sedimentation tank; 210. Liquid phase output end; 220. Solid phase output end; 30. Water source heat pump module; 40. Thermal hydrolysis module; 410. Reaction chamber; 411. Sludge input end; 412. Sludge output end; 420. Stirring blade; 421. Upstream surface; 422. Backstream surface; 423. Air hole; 430. Stirring shaft; 440. Drive unit; 50. Side flow tank; 60. Side flow pipeline; 610. Transfer pump; 70. Preheating module; 710. Outer casing; 720. Circulation pump; 730. Pressure relief branch; 740. Coupling; 80. Sludge return pipeline; 910. Control module; 920. Temperature detection unit. DETAILED DESCRIPTION

[0018] To make the objectives, technical solutions, and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other implementations obtained by those of ordinary skill in the art without inventive effort are within the scope of protection of the present invention.

[0019] The terms "first," "second," and the like in the specification and claims of this application are used to distinguish similar objects, and are not used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of this application can be implemented in an order other than that illustrated or described herein, and that the objects distinguished by "first," "second," and the like are generally of the same type, and do not limit the number of objects; for example, the first object can be one or more. In addition, the term "and / or" in the specification and claims refers to at least one of the connected objects, and the character " / " generally indicates that the objects connected are in an "or" relationship.

[0020] To address the issue of insufficient carbon source release in the sidestream process, existing activated sludge wastewater treatment systems typically utilize thermal sludge hydrolysis technology to treat the sidestream sludge. This technology uses high temperatures (120°C to 180°C) and high pressure to decompose sludge cell walls and release organic matter. However, thermal sludge hydrolysis technology requires a large amount of heat, necessitating a separate heat source to meet the heat requirements. This additional heat source not only increases the cost of the activated sludge wastewater treatment system but also reduces the energy efficiency of the entire system. To address the high cost and low energy efficiency associated with the use of thermal sludge hydrolysis technology in conjunction with the sidestream process, the present invention provides a wastewater treatment system and method that utilizes thermal sludge hydrolysis coupled with heat pump waste heat. This system utilizes waste heat from the secondary sedimentation tank effluent, improves the heat quality of the waste heat through heat pump technology, and then supplies it to the sludge thermal hydrolysis reaction. This system achieves a low-cost, high-energy-efficiency synergy between thermal sludge hydrolysis technology and the sidestream process, effectively increasing the concentration of the available carbon source. This is described in detail in the following embodiments.

[0021] Example 1

[0022] Some embodiments of the present application provide a sewage treatment system that combines side stream sludge thermal hydrolysis with heat pump waste heat, such as Figure 1 and Figure 2As shown, it includes a biochemical tank 10, a secondary sedimentation tank 20, a side flow tank 50, a thermal hydrolysis module 40 and a water source heat pump module 30. Along the sewage flow direction, the biochemical tank 10 and the secondary sedimentation tank 20 are arranged in sequence. The heat energy collection end of the water source heat pump module 30 is connected to the liquid phase output end 210 of the secondary sedimentation tank 20, and the heat energy output end of the water source heat pump module 30 is connected to the thermal hydrolysis module 40. The water source heat pump module 30 is used to collect the thermal energy of the liquid phase fluid in the liquid phase output end of the secondary sedimentation tank 20, and output it to the thermal hydrolysis module 40 after improving the thermal energy grade, so as to realize the thermal hydrolysis treatment of the sludge by the thermal hydrolysis module 40. The solid phase output end 220 of the secondary sedimentation tank 20 is connected to the sludge input end 411 of the thermal hydrolysis module 40 through the side flow pipeline 60, and the sludge output end 412 of the thermal hydrolysis module 40 is connected to the biochemical tank 10 through the side flow tank 50. The thermal hydrolysis module 40 is used to perform thermal hydrolysis treatment on the sludge flowing through. The sewage flowing out of the secondary sedimentation tank 20 generally has a temperature of 15°C~25°C, and there is a certain amount of waste heat that can be utilized. In addition, the secondary sedimentation tank 20 is close to the side stream pipeline 60, and the loss and cost in the heat transfer process are very low. Based on this, the water source heat pump module 30 performs heat exchange on the liquid phase output end 210 (sewage outlet) of the secondary sedimentation tank 20, extracts the heat in the sewage flowing out of the secondary sedimentation tank 20, and then uses the compressor in the water source heat pump module 30 to improve the thermal energy grade, and heats the heat exchange medium in the water source heat pump module 30 to 100°C~150°C, and then sends the heat exchange medium into the thermal hydrolysis module 40. Specifically, the sludge in the thermal hydrolysis module 40 can be heated by the heat exchange coil, and the sludge in the reaction chamber 410 is preferentially heated to 80℃~100℃ (low-temperature thermal hydrolysis is used to reduce excessive decomposition of activated sludge, preferentially release easily degradable carbon sources such as VFAs and monosaccharides, and increase the dissolved COD (SCOD) concentration in the sludge by 3~5 times), providing stable reaction temperature conditions for the thermal hydrolysis reaction of the sludge in the thermal hydrolysis module 40. The sludge after thermal hydrolysis enters the biochemical tank 10 through the side stream tank 50, realizing the synergy of sludge thermal hydrolysis technology and side stream process. Compared with the existing technology of separately configuring a heat source to provide reaction temperature conditions for the thermal hydrolysis module 40, the energy consumption of thermal hydrolysis is reduced due to the recovery and utilization of the waste heat of the sewage in the secondary sedimentation tank 20, the cost of supplying the thermal hydrolysis reaction temperature conditions is reduced, the energy utilization rate is improved, and the low-carbon operation of the sewage treatment system is realized.

[0023] It should be noted that the biochemical tank 10, secondary sedimentation tank 20, sidestream tank 50, and water-source heat pump technology can all be directly applied using existing technologies. The biochemical tank 10 uses microbial reactions to treat wastewater and degrade pollutants. The secondary sedimentation tank 20 separates wastewater into mud and water. The sidestream tank 50 buffers the sludge after the thermal hydrolysis reaction to prevent high-concentration pollutants from impacting the main process. The water-source heat pump module 30 is an energy-saving technology that transfers heat from a low-temperature heat source in the water source to a high-temperature heat source by consuming a small amount of high-quality energy (such as electricity). Specifically, it includes an evaporator for absorbing low-grade heat energy from the environment, a compressor for increasing the temperature and pressure of the refrigerant, a condenser for releasing the high-temperature heat to the target medium, and an expansion valve for reducing the refrigerant pressure. The water-source heat pump module 30 can use one part of electricity to transport three to five parts of ambient heat energy, making it more efficient than existing electric heating technologies and more economical than gas boilers.

[0024] In some embodiments, as Figure 3 and Figure 4 As shown, the sewage treatment system also includes a preheating module 70, which includes a gas-phase circulation pipeline and a heat exchange component arranged in the gas-phase circulation pipeline. The heat exchange component is arranged at the sludge input end 411 of the thermal hydrolysis module 40, and is used to preheat the sludge entering the thermal hydrolysis module 40. The thermal hydrolysis module 40 includes a reaction chamber 410, and the input end of the gas-phase circulation pipeline is connected to the top of the reaction chamber 410. The output end of the gas-phase circulation pipeline is arranged in the middle of the reaction chamber 410, and a circulation pump 720 is provided on the gas-phase circulation pipeline.

[0025] In some embodiments, in order to improve resource utilization, a heat exchange component can be provided, including an outer sleeve 710 provided on the pipeline of the sludge input end 411 of the thermal hydrolysis module 40, and a preheating air channel is provided between the outer sleeve 710 and the pipeline of the sludge input end 411 of the thermal hydrolysis module 40. The preheating air channel is used to form a gas phase circulation pipeline to achieve preheating of the sludge in the pipeline of the sludge input end 411 of the thermal hydrolysis module 40. Due to the high temperature in the reaction chamber 410, high-temperature and high-pressure water vapor is formed in the top cavity of the reaction chamber 410. The high-temperature and high-pressure water vapor is introduced into the heat exchange component by the gas phase circulation pipeline, which can reduce the temperature and pressure in the reaction chamber. At the same time, the water vapor preheats the sludge about to enter the reaction chamber 410 when passing through the preheating gas channel, which can relatively shorten the residence time of the sludge in the reaction chamber 410 and improve the efficiency and effect of the sludge thermal hydrolysis reaction. Then, the water vapor after heat exchange continues to pass through the gas phase circulation pipeline and enters the sludge undergoing thermal hydrolysis reaction in the reaction chamber 410, assisting the sludge thermal hydrolysis reaction to proceed uniformly and efficiently, and avoiding the accumulation of heat energy in the sludge. Part of the heat energy in the sludge is taken away to the top cavity area of ​​the reaction chamber 410, so that the sludge undergoing thermal hydrolysis reaction maintains a relatively stable temperature environment, and realizes auxiliary adjustment of the temperature and reaction pressure conditions of the thermal hydrolysis reaction. On the basis of improving the temperature stability of the thermal hydrolysis reaction, the utilization efficiency of the thermal energy resources of the thermal hydrolysis module 40 is effectively improved, the energy efficiency of the thermal hydrolysis module 40 and the sewage treatment system is improved, and the system operating cost is reduced.

[0026] In some embodiments, in order to optimize the sludge thermal hydrolysis reaction effect, the thermal hydrolysis module 40 can be configured to further include a driving unit 440 and a stirring blade 420 provided in the reaction chamber 410. The driving unit 440 is used to control the rotation of the stirring blade 420 by driving the stirring shaft 430. The stirring blade 420 is provided with an air hole 423. The gas phase circulation pipeline further includes a gas transmission channel provided in the stirring shaft 430. The input end of the gas transmission channel is connected to the output end of the circulation pump 720 through the coupling 740. The coupling 740 is used to ensure that the gas transmission channel and the circulation pump 720 are connected. On the basis of gas path connectivity, the rotation of the stirring shaft 430 will not be affected. The output end of the gas transmission channel is connected to the air hole 423, and the stirring blade 420 is fixedly connected to the stirring shaft 430. When the sludge thermal hydrolysis reaction is carried out, the rotation of the stirring blade 420 can be selectively controlled to accelerate heat conduction, so that the temperature in the reaction chamber 410 is more evenly distributed, avoiding local overheating or insufficient reaction. On the other hand, the shear force generated on the sludge during the rotation of the stirring blade 420 can further destroy the sludge body and the cell wall of the microorganism, promote the release of intracellular organic matter, and increase the production of carbon sources. When the gas phase circulation pipeline is in working condition, the water vapor in the top cavity of the reaction chamber 410 is sucked into the gas phase circulation pipeline, and the sludge about to enter the reaction chamber 410 is preheated when passing through the preheating gas channel. Then the water vapor enters the gas transmission channel in the stirring shaft 430 through the coupling 740, and then enters the sludge through the air hole 423, which can accelerate the removal of heat energy in the sludge, avoid local overheating, reasonably control the temperature fluctuation range inside the hot hydrolysis sludge, accelerate the contact between sludge particles and high-temperature water / steam, enhance the hydrolysis reaction kinetics, and shorten the reaction time.

[0027] Preferably, the coupling 740 is arranged outside the reaction chamber 410, and the driving unit 440 is a conventional technology and can adopt a servo motor, which will not be described in detail here.

[0028] In some embodiments, in order to prevent the sludge from clogging the air holes 423 during the operation of the stirring blade 420, as shown in FIG. Figure 5 As shown, the air hole 423 can be arranged on the back flow surface 422 of the stirring blade 420 to reduce the risk of the air hole 423 being blocked during operation and improve the operation stability and safety of the gas phase circulation pipeline. During the rotation of the stirring blade 420, the contact surface that directly contacts the sludge is the upstream surface 421, and the side corresponding to the upstream surface 421 is the back flow surface 422.

[0029] In some embodiments, in order to ensure the stable progress of the sludge thermal hydrolysis reaction, the stirring blade 420 can be arranged along the gravity direction, between the sludge input end 411 of the thermal hydrolysis module 40 and the sludge output end 412 of the thermal hydrolysis module 40, and the sludge output end 412 of the thermal hydrolysis module 40 is located at the bottom of the reaction chamber 410, so as to control the residence time of the sludge in the reaction chamber 410. Accordingly, the heat energy inlet of the heat energy output end of the water source heat pump module 30 is close to the sludge input end 411, and the heat energy outlet is close to the sludge output end 412, so as to improve the heating efficiency of the sludge.

[0030] In some embodiments, the input end of the gas-phase circulation pipeline is located above the sludge input end 411 of the thermal hydrolysis module 40, so that the input end of the gas-phase circulation pipeline is in the top cavity of the reaction chamber 410, and the newly entered sludge in the reaction chamber 410 will not affect the input end of the gas-phase circulation pipeline.

[0031] In some embodiments, since the temperature of the sewage generated by the secondary sedimentation tank 20 is greatly affected by the ambient temperature, the temperature of the sewage generated by the secondary sedimentation tank 20 will fluctuate to a certain extent at different times of the same day or in different seasons, which will cause the heat energy output by the water source heat pump module 30 to the thermal hydrolysis module 40 to have certain fluctuations. In order to reduce the unstable effect caused by the ambient temperature fluctuation, a delivery pump 610 can be provided on the side stream pipeline 60. The sewage treatment system also includes a control module 910. The control module 910 is configured to: determine the power of the delivery pump 610 and the circulation pump 720 based on the fluid temperature in the liquid phase output end of the secondary sedimentation tank 20; in actual application, the upper and lower limits of the heat energy that the water source heat pump module 30 can output can be calculated based on the sewage temperature change curve generated by the secondary sedimentation tank 20 collected in advance. When the temperature of the sewage generated in the secondary sedimentation tank 20 becomes low, the control module 910 can be controlled The delivery pump 610 reduces the sludge delivery volume, thereby reducing the sludge thermal hydrolysis reaction volume and / or the sludge residence time in the reaction chamber 410. When the temperature of the sewage generated in the secondary sedimentation tank 20 becomes high, the circulation pump 720 can be controlled to work, and part of the heat energy in the reaction chamber 410 can be used to preheat the sludge through the gas phase circulation pipeline. Furthermore, the power of the delivery pump 610 can be increased synchronously to increase the sludge volume in the reaction chamber 410 and / or shorten the sludge residence time in the reaction chamber 410. In this way, when the sewage temperature fluctuates due to ambient temperature fluctuations, the thermal hydrolysis reaction in the sewage treatment system will not only not be affected by this situation, but the temperature change brought about by the fluctuation can also be used to flexibly adjust the working state of the thermal hydrolysis module 40. On the basis of improving the efficiency and effect of the thermal hydrolysis reaction, the resource utilization efficiency is improved, and the peak thermal energy waste and the reduction of the valley thermal hydrolysis reaction effect are avoided.

[0032] In some embodiments, in order to improve the flexibility of system regulation, the gas phase circulation pipeline can be set to also include a pressure relief branch 730. The heat exchange component is located between the pressure relief branch 730 and the input end of the gas phase circulation pipeline. The pressure relief branch 730 is used to control the air pressure in the gas phase circulation pipeline to be within a preset value. When the temperature in the reaction chamber 410 is too high, the water vapor after preheating the sludge can be discharged from the gas phase circulation pipeline through the pressure relief branch 730, thereby reducing the temperature and pressure in the reaction chamber 410, increasing the regulation means of the thermal hydrolysis module 40, realizing the automatic regulation of the thermal hydrolysis module 40, and ensuring the stability of the sludge thermal hydrolysis reaction.

[0033] In some embodiments, to improve the flexibility of system control, such as Figure 6 As shown, the control module 910 can be set to be further configured to: determine the preset value based on the temperature in the reaction chamber 410; when the temperature in the reaction chamber 410 is too high, the pressure relief branch 730 is automatically operated by the set preset value, and when the sludge parameters themselves change greatly, the thermal hydrolysis reaction conditions need to be adaptively adjusted. At this time, the pressure relief branch 730 can be adaptively adjusted to open the required preset value.

[0034] In some embodiments, in order to realize the automatic operation of system regulation, the sewage treatment system can be set to also include a temperature detection unit 920, which is used to detect the output end of the secondary sedimentation tank 20 and / or the temperature inside the reaction chamber 410. The temperature detection unit 920 is connected to the control module 910. The control module 910 receives the monitoring signal of the temperature detection unit 920 and controls the delivery pump 610 and the circulation pump 720 to make corresponding responses.

[0035] In some embodiments, the sewage treatment system further includes a sludge return pipeline 80 , and the secondary sedimentation tank 20 is connected to the biochemical tank 10 through the sludge return pipeline 80 .

[0036] In some embodiments, a delivery pump 610 connected to the control module 910 is respectively provided on the sludge return pipeline 80 and the sludge output end 412 of the thermal hydrolysis module 40 .

[0037] Example 2

[0038] Some embodiments of the present application provide a sewage treatment method, which uses the sewage treatment system in Example 1 to treat sewage.

[0039] In the actual working process, the sewage is first allowed to enter the biochemical tank 10, and the biochemical tank 10 is used to perform microbial reaction treatment on the sewage to degrade organic matter in the sewage. Then the sewage flows into the secondary sedimentation tank 20, and the secondary sedimentation tank 20 is used to perform mud-water separation treatment on the sewage. The sludge produced in the secondary sedimentation tank 20 can be returned to the biochemical tank 10 through the sludge return pipe 80, and can also be transported to the thermal hydrolysis module 40 through the side stream pipe 60 for sludge thermal hydrolysis reaction. At the same time, the water source heat pump module 30 performs heat exchange on the liquid phase output end 210 (sewage outlet) of the secondary sedimentation tank 20 to extract heat from the sewage flowing out of the secondary sedimentation tank 20, and then the heat energy grade is improved by the compressor in the water source heat pump module 30, and the heat exchange medium in the water source heat pump module 30 is heated to 100°C~150°C, and then the heat exchange medium is sent to the thermal hydrolysis module 40. The sludge in the thermal hydrolysis module 40 can be heated by a heat exchange coil, and the sludge in the reaction chamber 410 is preferentially heated to 80°C~100°C (low-temperature thermal hydrolysis is used to reduce excessive decomposition of activated sludge, and to preferentially release easily degradable carbon sources such as VFAs and monosaccharides, so that the dissolved COD (SCOD) concentration in the sludge is increased by 3~5 times), providing stable reaction temperature conditions for the thermal hydrolysis reaction of the sludge in the thermal hydrolysis module 40. After the thermal hydrolysis reaction, the sludge flows to the biochemical tank 10 through the side stream tank 50, realizing the synergy of the sludge thermal hydrolysis technology and the side stream process. Compared with the prior art in which a heat source is separately configured to provide reaction temperature conditions for the thermal hydrolysis module, the waste heat of the sewage in the secondary sedimentation tank 20 is recovered and utilized, thereby effectively reducing the energy consumption of thermal hydrolysis, reducing the cost of supplying the thermal hydrolysis reaction temperature conditions, improving energy utilization, and realizing low-carbon operation.

[0040] In some embodiments, the temperature of the sewage flowing out of the secondary sedimentation tank 20 can be obtained. When the temperature of the sewage generated in the secondary sedimentation tank 20 becomes low, the delivery pump 610 can be controlled to reduce the sludge delivery amount, thereby reducing the sludge thermal hydrolysis reaction amount and / or the sludge residence time in the reaction chamber 410. When the temperature of the sludge generated in the secondary sedimentation tank 20 becomes high, the circulation pump 720 can be controlled to work, and part of the heat energy in the reaction chamber 410 can be used through the gas phase circulation pipeline to preheat the sludge that is about to undergo thermal hydrolysis reaction. Furthermore, the power of the delivery pump 610 can be increased simultaneously to increase the amount of sludge in the reaction chamber 410 and / or shorten the sludge residence time in the reaction chamber 410. In this way, when the sewage temperature fluctuates due to ambient temperature fluctuations, the thermal hydrolysis reaction will not only not be affected by this situation, but the temperature change brought about by the fluctuation can also be used to flexibly adjust the working state of the thermal hydrolysis module 40. On the basis of improving the efficiency and effect of the thermal hydrolysis reaction, the resource utilization efficiency is improved, and the peak thermal energy waste and the reduction of the valley thermal hydrolysis reaction effect are avoided.

[0041] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.

[0042] Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of the present application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in reverse order depending on the functions involved. For example, the methods described may be performed in an order different from that described, and various steps may be added, omitted, or combined. Furthermore, features described with reference to certain examples may be combined in other examples.

[0043] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed by the present invention, which should be covered by the scope of protection of the present invention.

Claims

1. A sewage treatment system using side stream sludge thermal hydrolysis coupled with heat pump waste heat, characterized in that: The utility model comprises a biochemical tank, a secondary sedimentation tank, a side flow tank, a thermal hydrolysis module, a preheating module and a water source heat pump module. The biochemical tank and the secondary sedimentation tank are sequentially arranged along the flow direction of sewage. The heat energy collection end of the water source heat pump module is connected to the liquid phase output end of the secondary sedimentation tank, and the heat energy output end of the water source heat pump module is connected to the thermal hydrolysis module. The water source heat pump module is used to collect the heat energy of the liquid phase fluid in the liquid phase output end of the secondary sedimentation tank, and output it to the thermal hydrolysis module after improving the heat energy grade, so as to realize the thermal hydrolysis treatment of the sludge by the thermal hydrolysis module. The solid phase output end of the secondary sedimentation tank is connected to the input end of the thermal hydrolysis module through a side flow pipeline, and the output end of the thermal hydrolysis module is connected to the biochemical tank through the side flow tank. The thermal hydrolysis module is used to perform thermal hydrolysis treatment on the sludge flowing through. The preheating module comprises a gas phase circulation pipeline and a heat exchange component arranged in the gas phase circulation pipeline. The heat exchange component is arranged at the input end of the thermal hydrolysis module for The sludge is preheated in the thermal hydrolysis module. The thermal hydrolysis module includes a reaction chamber, the input end of the gas circulation pipeline is connected to the top of the reaction chamber, the output end of the gas circulation pipeline is arranged in the middle of the reaction chamber, and a circulation pump is provided on the gas circulation pipeline; the heat exchange component includes an outer sleeve arranged on the input end pipeline of the thermal hydrolysis module, and a preheating air channel is provided between the outer sleeve and the input end pipeline of the thermal hydrolysis module. The preheating air channel is used to constitute a gas circulation pipeline to achieve preheating of the sludge in the input end pipeline of the thermal hydrolysis module; the thermal hydrolysis module also includes a driving unit and a stirring blade arranged in the reaction chamber, the driving unit is used to control the rotation of the stirring blade by driving the stirring shaft, and the stirring blade is provided with an air hole, and the gas circulation pipeline also includes a gas transmission channel provided in the stirring shaft, the input end of the gas transmission channel is connected to the output end of the circulation pump through a coupling, and the output end of the gas transmission channel is connected to the air hole.

2. A sewage treatment system using side stream sludge thermal hydrolysis coupled with heat pump waste heat according to claim 1, characterized in that: The air holes are arranged on the backflow surface of the stirring blade.

3. The sewage treatment system of side stream sludge thermal hydrolysis coupled with heat pump waste heat according to claim 1, characterized in that: Along the gravity direction, the stirring blade is located between the input end and the output end of the thermal hydrolysis module, and the output end of the thermal hydrolysis module is located at the bottom of the reaction chamber.

4. The sewage treatment system of side stream sludge thermal hydrolysis coupled with heat pump waste heat according to claim 1, characterized in that: The input end of the gas phase circulation pipeline is located above the input end of the thermal hydrolysis module.

5. The sewage treatment system of side stream sludge thermal hydrolysis coupled with heat pump waste heat according to claim 1, characterized in that: A delivery pump is provided on the side stream pipeline. The sewage treatment system further comprises a control module, which is configured to determine the power of the delivery pump and the circulation pump based on the fluid temperature in the liquid phase output end of the secondary sedimentation tank.

6. The sewage treatment system of side stream sludge thermal hydrolysis coupled with heat pump waste heat according to claim 5, characterized in that: The gas phase circulation pipeline also includes a pressure relief branch. The heat exchange component is located between the pressure relief branch and the input end of the gas phase circulation pipeline. The pressure relief branch is used to control the gas pressure in the gas phase circulation pipeline to be within a preset value.

7. The sewage treatment system of side stream sludge thermal hydrolysis coupled with heat pump waste heat according to claim 6, characterized in that: The control module is further configured to determine the preset value based on the temperature in the reaction chamber.

8. A sewage treatment system using side stream sludge thermal hydrolysis coupled with heat pump waste heat according to any one of claims 1 to 7, characterized in that: The sewage treatment system further comprises a temperature detection unit, which is used to detect the temperature at the output end of the secondary sedimentation tank and / or the temperature in the reaction chamber; And / or, the sewage treatment system further includes a sludge return pipeline, and the secondary sedimentation tank is connected to the biochemical tank through the sludge return pipeline.

9. A sewage treatment method, characterized in that: The sewage is treated using the sewage treatment system described in any one of claims 1 to 8.

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