Sludge anaerobic fermentation system

Abstract

The utility model discloses a sludge anaerobic fermentation system which comprises a sludge pretreatment unit used for adding ozone microbubbles into a sludge mixed solution to obtain a pretreated sludge mixed solution and conveying the pretreated sludge mixed solution to a sludge anaerobic fermentation unit; the sludge anaerobic fermentation unit is communicated with the sludge pretreatment unit and is used for performing anaerobic fermentation on the pretreated sludge mixed liquid. The ozone and the microbubbles are combined to form the ozone microbubbles, and the ozone microbubbles are utilized to pretreat the sludge, so that the oxidation efficacy of the ozone can be fully utilized, the damage of microbial cell walls and the decomposition of macromolecular organic matters are accelerated, the sludge hydrolysis rate is increased, and the anaerobic fermentation efficiency is further improved.

Description

Technical Field

[0001] This utility model relates to the field of sludge fermentation technology, and in particular to a sludge anaerobic fermentation system. Background Technology

[0002] Currently, urban wastewater treatment plants widely adopt the activated sludge process, which utilizes the metabolic activity of microorganisms to adsorb, assimilate, degrade, and transform pollutants in water, thereby purifying wastewater. As a byproduct of wastewater treatment, the activated sludge process inevitably generates a large amount of excess sludge. If this excess sludge is not further treated, it will pose a risk of secondary pollution to the environment.

[0003] Waste sludge possesses both "resource" and "pollution" attributes. To promote sludge treatment and disposal, reduce landfill volume, and achieve resource recovery and utilization of waste sludge resources and energy, waste sludge anaerobic fermentation for methanogenesis and other waste reduction and resource utilization technologies have emerged. Specifically, anaerobic fermentation for methanogenesis typically involves three stages: hydrolysis, acid production, and methanogenesis. However, in existing anaerobic fermentation for methanogenesis systems, the sludge hydrolysis rate is relatively slow, resulting in low anaerobic fermentation efficiency.

[0004] Therefore, there is an urgent need for an anaerobic fermentation system for sludge to solve the problem of low efficiency in existing anaerobic fermentation technologies. Utility Model Content

[0005] In view of this, the present invention provides a sludge anaerobic fermentation system and a system operation control method, the main purpose of which is to solve the problem of low efficiency in sludge anaerobic fermentation.

[0006] To address the above problems, this application provides a sludge anaerobic fermentation system, comprising:

[0007] The sludge pretreatment unit is used to add ozone microbubbles to the sludge mixture to obtain oxidative pretreated sludge mixture, and then transport the pretreated sludge mixture to the sludge anaerobic fermentation unit.

[0008] The sludge anaerobic fermentation unit is connected to the sludge pretreatment unit and is used to perform anaerobic fermentation on the pretreated sludge mixture.

[0009] Optionally, the sludge anaerobic fermentation system further includes: a filtration unit for pre-filtering the sludge mixture, the filtration unit specifically comprising:

[0010] A sludge cutter is installed on the sludge conveying pipeline and is used to cut impurities in the sludge mixture.

[0011] A vibrating filter is installed after the sludge cutter to filter impurities in the sludge mixture and obtain the filtered sludge mixture.

[0012] Optionally, the sludge pretreatment unit includes:

[0013] A sludge oxidation tank is used to oxidize the sludge in the sludge mixture in a continuous flow manner;

[0014] An ozone generator is used to supply ozone to the sludge oxidation tank.

[0015] A microbubble disperser is used to generate microbubbles and add them to the sludge oxidation tank;

[0016] A circulating pump is installed outside the sludge oxidation tank. The outlet of the circulating pump is connected to the inlet of the jet mixer through a pipeline. It is used to extract the sludge mixture in the sludge oxidation tank and transport the sludge mixture to the jet mixer.

[0017] The jet mixer is located outside the sludge oxidation tank. The air inlet of the jet mixer is connected to the air outlet of the ozone generator through a pipeline. It is used to receive ozone delivered by the ozone generator and mix the ozone with the sludge mixture. The liquid outlet of the jet mixer is connected to the liquid inlet of the microbubble disperser through a pipeline. It is used to transport the sludge mixture containing ozone to the microbubble disperser.

[0018] Optionally, the sludge pretreatment unit further includes an ozone exhaust gas destroyer; the ozone exhaust gas destroyer is located outside the sludge oxidation tank and is used to extract exhaust gas from the top of the sludge oxidation tank through pipelines and to destroy and decompose the ozone in the exhaust gas.

[0019] The anaerobic fermentation system for sludge in this application combines ozone with microbubbles to form ozone microbubbles. These ozone microbubbles are then used to pretreat the sludge, fully utilizing the oxidizing power of ozone to accelerate the breakdown of microbial cell walls and the decomposition of macromolecular organic matter, thereby increasing the sludge hydrolysis rate and ultimately improving the efficiency of anaerobic fermentation. Furthermore, the ozone dosage in this application is low, and the sludge pretreatment system is simple and easy to operate.

[0020] The above description is merely an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this utility model more obvious and understandable, specific embodiments of this utility model are given below. Attached Figure Description

[0021] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0022] Figure 1 This is a schematic diagram of the system architecture of a sludge anaerobic fermentation system according to an embodiment of this application;

[0023] Figure 2 This is a flowchart of a system operation control method according to another embodiment of this application. Detailed Implementation

[0024] Various embodiments and features of this application are described herein with reference to the accompanying drawings.

[0025] It should be understood that various modifications can be made to the embodiments described herein. Therefore, the above description should not be considered as limiting, but merely as an example of embodiments. Other modifications within the scope and spirit of this application will be apparent to those skilled in the art.

[0026] The accompanying drawings, which are included in and form part of this specification, illustrate embodiments of the present application and, together with the general description of the present application given above and the detailed description of the embodiments given below, serve to explain the principles of the present application.

[0027] These and other features of this application will become apparent from the following description of preferred forms of embodiments given as non-limiting examples, with reference to the accompanying drawings.

[0028] It should also be understood that although this application has been described with reference to some specific examples, those skilled in the art can certainly implement many other equivalent forms of this application.

[0029] The above and other aspects, features and advantages of this application will become more apparent when taken in conjunction with the accompanying drawings and in view of the following detailed description.

[0030] Specific embodiments of this application are described thereafter with reference to the accompanying drawings; however, it should be understood that the claimed embodiments are merely examples of this application, which can be implemented in various ways. Well-known and / or repeated functions and structures are not described in detail to avoid unnecessary or redundant details that could obscure the application. Therefore, the specific structural and functional details claimed herein are not intended to be limiting, but merely serve as the basis and representative basis for the claims to teach those skilled in the art to use this application in a variety of substantially any suitable detailed structures.

[0031] This specification may use the phrases “in one embodiment,” “in another embodiment,” “in yet another embodiment,” or “in other embodiments,” all of which may refer to one or more of the same or different embodiments according to this application.

[0032] This application provides a sludge anaerobic fermentation system, such as... Figure 1 As shown, the system in this embodiment includes: a filtration unit 1, a sludge pretreatment unit 2, and a sludge anaerobic fermentation unit 3. The filtration unit 1 is used to filter impurities in the sludge mixture, preventing clogging and rapid wear in the subsequent sludge pretreatment unit due to impurities. In this embodiment, the sludge pretreatment unit 2 adds ozone microbubbles to the filtered sludge mixture to obtain an oxidized pretreated sludge mixture, which is then transported to the sludge anaerobic fermentation unit 3. The sludge anaerobic fermentation unit 3 is connected to the sludge pretreatment unit and is used to perform anaerobic fermentation on the pretreated sludge mixture. In the specific implementation process of this embodiment, the pretreated sludge mixture is first deoxygenated before being transported to the sludge anaerobic fermentation unit.

[0033] The sludge anaerobic fermentation system in this embodiment combines ozone with microbubbles to form ozone microbubbles. Utilizing these ozone microbubbles for sludge pretreatment fully leverages the oxidizing power of ozone, accelerating the breakdown of microbial cell walls and the decomposition of macromolecular organic matter, thereby increasing the sludge hydrolysis rate and ultimately improving anaerobic fermentation efficiency. Furthermore, this application employs a low ozone dosage, resulting in a simple and convenient sludge pretreatment system.

[0034] Based on the above embodiments, another embodiment of this application provides a sludge anaerobic fermentation system. In this embodiment, the filtration unit specifically includes a sludge cutter and a vibrating filter. Specifically, the sludge cutter is installed on the sludge conveying pipeline and is used to cut impurities in the sludge mixture; the vibrating filter is installed after the sludge cutter and is used to filter impurities in the sludge mixture in the filtration tank to obtain filtered sludge mixture. In this embodiment, the outlet of the vibrating filter is connected to the sludge oxidation tank through a pipeline, and is used to transport the filtered sludge mixture to the sludge oxidation tank.

[0035] In this embodiment, the sludge pretreatment unit specifically includes: a sludge oxidation tank, an ozone generator, a microbubble disperser, a circulating pump, and a jet mixer.

[0036] The sludge oxidation tank is used to oxidize the sludge in the sludge mixture in a continuous flow manner. That is, the sludge mixture flows into the sludge oxidation tank through the sludge inlet and undergoes oxidation treatment to obtain pretreated sludge mixture. The pretreated sludge mixture flows out of the sludge oxidation tank through the sludge outlet.

[0037] A circulating pump is located outside the sludge oxidation tank, and its inlet is connected to the bottom of the sludge oxidation tank via a pipeline. The outlet of the circulating pump is connected to the inlet of the jet mixer via a pipeline, and is used to extract sludge mixture from the sludge oxidation tank and transport the sludge mixture to the jet mixer.

[0038] A jet mixer is installed outside the sludge oxidation tank. The air inlet of the jet mixer is connected to the air outlet of the ozone generator via a pipeline, used to receive ozone supplied by the ozone generator and mix the ozone with the sludge mixture. The liquid outlet of the jet mixer is connected to the liquid inlet of the microbubble disperser via a pipeline, used to transport the ozone-containing sludge mixture to the microbubble disperser, whereby the microbubble disperser can form ozone microbubbles based on ozone and disperse the ozone microbubbles into the sludge mixture. In this embodiment, the sludge pretreatment unit also includes an ozone exhaust gas destroyer. The ozone microbubble destroyer is installed outside the oxidation tank, extracts exhaust gas from the top of the sludge oxidation tank via a pipeline, and destroys and decomposes the ozone in the exhaust gas.

[0039] The sludge anaerobic fermentation system in this embodiment combines ozone with microbubbles to form ozone microbubbles. Using these ozone microbubbles to pretreat the sludge effectively improves ozone utilization efficiency and sludge decomposition rate, thereby increasing the efficiency of anaerobic fermentation. This invention features low ozone dosage, a simple sludge pretreatment system, and convenient operation, making it highly practical.

[0040] Another embodiment of this application provides a system operation control method, such as... Figure 2 As shown, the method, applied to any of the above-mentioned anaerobic fermentation systems for sludge, includes:

[0041] Step S101: Control the sludge pretreatment unit to add ozone microbubbles to the sludge mixture to obtain the sludge mixture after oxidation pretreatment.

[0042] Step S102: Control the anaerobic fermentation unit to perform anaerobic fermentation treatment on the pretreated sludge mixture.

[0043] In this embodiment, before adding ozone microbubbles to the sludge mixture, the method further includes controlling the moisture content of the sludge mixture to achieve a target moisture content; the target moisture content ranges from 96% to 98%. When controlling the ozone generator to add ozone to the sludge mixture, the ozone content at the outlet of the ozone generator ranges from 50 to 150 g / Nm³. 3The ozone dosage range is 5g(O3) / Kg (oven-dried sludge) to 10g(O3) / Kg (oven-dried sludge); when controlling the addition of ozone microbubbles to the sludge mixture using a microbubble disperser, the inlet water pressure of the microbubble disperser ranges from 0.15MPa to 0.4MPa. In this embodiment, by controlling the ozone content and dosage, the addition of ozone can be made more reasonable and accurate, ensuring rapid hydrolysis of the sludge while avoiding ozone waste, thus laying the foundation for improving the efficiency of anaerobic fermentation of sludge.

[0044] The system operation control method in this embodiment also includes controlling the sludge oxidation tank to operate in a continuous flow mode, with a hydraulic retention time ranging from 5 to 7 hours. In this embodiment, by controlling the hydraulic retention time, the ozone microbubbles and sludge mixture can be mixed more thoroughly and evenly, ensuring sufficient oxidation time and laying the foundation for accelerating sludge hydrolysis and improving the efficiency of anaerobic fermentation.

[0045] The system operation control method in this embodiment further includes controlling the ratio of the circulation flow rate of the sludge oxidation tank to the sludge inlet flow rate of the sludge oxidation tank to be between 20:1 and 50:1. In this embodiment, by controlling the ratio of the circulation flow rate of the circulation pump to the sludge inlet flow rate of the sludge oxidation tank, the ozone microbubbles and the sludge mixture can be mixed more thoroughly and evenly, ensuring the formation effect of microbubbles and laying the foundation for accelerating the hydrolysis of sludge in the sludge mixture and improving the anaerobic fermentation efficiency of sludge.

[0046] In this embodiment, before adding ozone microbubbles to the sludge mixture, the moisture content of the sludge mixture can be controlled to be 96-98%. The sludge mixture is then transported through pipelines to a sludge cutter to cut impurities; and then filtered through a vibrating filter to obtain a filtered sludge mixture. This filtered sludge mixture is then transported to a sludge oxidation tank, which operates in a continuous flow mode with a hydraulic retention time of 5-7 hours. A circulation pump at the bottom of the sludge oxidation tank draws the sludge mixture from the tank, which then passes through a jet mixer and a microbubble disperser before returning to the oxidation tank, completing the circulation of the mixture and the formation and release of ozone microbubbles. The ratio of the circulating flow rate of the sludge mixture pumped by the circulating pump to the sludge inlet flow rate of the sludge oxidation tank is controlled to be between 20:1 and 50:1, while the inlet water pressure of the microbubble disperser is controlled between 0.15-0.4 MPa. In specific implementation of this embodiment, the ozone content of the ozone generator outlet gas can also be controlled between 50-150 g / Nm³ based on the organic matter content of the sludge. 3The ozone dosage is controlled at 5-10 g (O3) / Kg (ozone-dry sludge) (i.e., the ozone dosage per kilogram of ozone-dry sludge is between 5 and 10 g), and the amount of ozone introduced into the system can be dynamically adjusted according to the amount of sludge entering the sludge oxidation tank. Finally, the sludge mixture after ozone microbubble pretreatment enters the sludge anaerobic fermentation treatment unit. In this embodiment, after obtaining the pretreated sludge mixture, it can be deoxygenated first, and then the deoxygenated sludge mixture can be mixed with digested sludge in a predetermined ratio to obtain the target sludge mixture. Then, the target sludge mixture is subjected to anaerobic fermentation, and methane is generated after a predetermined fermentation time.

[0047] The following describes an anaerobic fermentation experiment using a sludge anaerobic fermentation system as described in this application. The anaerobic fermentation system described in this embodiment is as follows: Figure 1 As shown, it includes: 1. a filtration unit; 2. a sludge pretreatment unit; and 3. a sludge anaerobic fermentation unit.

[0048] Experiment 1:

[0049] Specifically, the sludge used in the experiment was the residual sludge from the sludge thickening tank of a wastewater treatment plant. The main indicators of the sludge were as follows: sludge moisture content 97.5%; sludge organic component ratio 63%.

[0050] The excess sludge first enters the sludge filtration unit through pipelines to remove large particles of inorganic matter, hair, and other impurities. Then, the sludge mixture enters the sludge oxidation tank through pipelines, where pretreatment of the sludge is completed under the action of ozone microbubbles. The sludge oxidation tank operates in a continuous flow mode, with a hydraulic retention time controlled at 7 hours. A circulating pump extracts the mixture from the sludge oxidation tank, passing it sequentially through a jet mixer and a microbubble disperser before returning it to the sludge oxidation tank, completing the circulation of the mixture and the formation and release of ozone microbubbles. The ratio of the circulation flow rate to the sludge inlet flow rate to the sludge oxidation tank is controlled at 40:1, while the water pressure entering the microbubble disperser is controlled at 0.20 MPa. The ozone content of the gas exiting the ozone generator is controlled at 110 g / Nm³. 3 The ozone dosage was controlled at 8 g (O3) / Kg (octane-dried sludge). The pretreated sludge mixture was deoxygenated, and then 100 ml of the deoxygenated sludge mixture was mixed with 300 ml of digested sludge for anaerobic fermentation. After one fermentation cycle, the amount of methane produced was measured to be 440 ml.

[0051] Experiment 2:

[0052] The sludge used in the experiment was the residual sludge from the sludge thickening tank of a wastewater treatment plant. The main indicators of the sludge were as follows: sludge moisture content 97.5%; sludge organic component ratio 63%.

[0053] The excess sludge first enters the sludge filtration unit through pipelines to remove large particles of inorganic matter, hair, and other impurities. Then, the sludge mixture enters the sludge oxidation tank through pipelines, where pretreatment of the sludge is completed under the action of ozone microbubbles. The sludge oxidation tank operates in a continuous flow mode, with a hydraulic retention time controlled at 5 hours. A circulating pump extracts the mixture from the sludge oxidation tank, passing it sequentially through a jet mixer and a microbubble disperser before returning it to the sludge oxidation tank, completing the circulation of the mixture and the formation and release of ozone microbubbles. The ratio of the circulation flow rate to the sludge inlet flow rate to the sludge oxidation tank is controlled at 40:1, while the water pressure entering the microbubble disperser is controlled at 0.20 MPa. The ozone content of the gas exiting the ozone generator is controlled at 110 g / Nm³. 3 The ozone dosage was controlled at 8 g (O3) / Kg (octaneously dry sludge). The pretreated sludge mixture was deoxygenated, and then 100 ml of the deoxygenated sludge mixture was mixed with 300 ml of digested sludge for anaerobic fermentation. After one fermentation cycle, the amount of methane produced was measured to be 390 ml.

[0054] Experiment 3:

[0055] The sludge used in the experiment was excess sludge from the sludge thickening tank of a wastewater treatment plant. Its main indicators were as follows: sludge moisture content 97.5%; organic component content 63%. The experimental system was as follows: Figure 1 As shown.

[0056] The excess sludge first enters the sludge filtration unit through pipelines to remove large particles of inorganic matter, hair, and other impurities. Then, the sludge mixture enters the sludge oxidation tank through pipelines, where pretreatment of the sludge is completed under the action of ozone microbubbles. The sludge oxidation tank operates in a continuous flow mode, with a hydraulic retention time controlled at 7 hours. A circulating pump extracts the mixture from the sludge oxidation tank, passing it sequentially through a jet mixer and a microbubble disperser before returning it to the sludge oxidation tank, completing the circulation of the mixture and the formation and release of ozone microbubbles. The ratio of the circulation flow rate to the sludge inlet flow rate to the sludge oxidation tank is controlled at 20:1, while the water pressure entering the microbubble disperser is controlled at 0.10 MPa. The ozone content of the gas exiting the ozone generator is controlled at 110 g / Nm³. 3 The ozone dosage was controlled at 8 g (O3) / Kg (octaneously dry sludge). The pretreated sludge mixture was deoxygenated, and then 100 ml of the deoxygenated sludge mixture was mixed with 300 ml of the digested sludge from the same example above for anaerobic fermentation. After one fermentation cycle, the amount of methane produced was measured to be 283 ml.

[0057] Experiment 4:

[0058] The sludge used in the experiment was the residual sludge from the sludge thickening tank of a wastewater treatment plant. The main indicators of the sludge were as follows: sludge moisture content 97.5%; sludge organic component ratio 63%.

[0059] Take 100ml of the test sludge mixture that has not been pretreated with ozone microbubbles, deoxygenate it and mix it with 300ml of the digested sludge of the same example as above for anaerobic fermentation. After one fermentation cycle, the amount of methane produced is measured to be 180ml.

[0060] By comparing the above-mentioned anaerobic fermentation experiments 1 and 2 with experiments 3 and 4, it can be seen that using the anaerobic fermentation system of this application and carrying out anaerobic fermentation treatment of sludge according to the system operation control method in this application can increase the methane production. Therefore, the anaerobic fermentation system and system operation control method in this application can improve the efficiency of anaerobic fermentation of sludge.

[0061] The above embodiments are merely exemplary embodiments of this application and are not intended to limit this application. The scope of protection of this application is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to this application within its substance and scope of protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of this application.

Claims

1. A sludge anaerobic fermentation system, characterized in that, include: The sludge pretreatment unit is used to add ozone microbubbles to the sludge mixture to obtain oxidative pretreated sludge mixture, and then transport the pretreated sludge mixture to the sludge anaerobic fermentation unit. The sludge anaerobic fermentation unit is connected to the sludge pretreatment unit and is used to perform anaerobic fermentation on the pretreated sludge mixture.

2. The system as described in claim 1, characterized in that, The system further includes a filtration unit for pre-filtering the sludge mixture, the filtration unit specifically comprising: A sludge cutter is installed on the sludge conveying pipeline and is used to cut impurities in the sludge mixture. A vibrating filter is installed after the sludge cutter to filter impurities in the sludge mixture and obtain the filtered sludge mixture.

3. The system as described in claim 1, characterized in that, The sludge pretreatment unit includes: A sludge oxidation tank is used to oxidize the sludge in the sludge mixture in a continuous flow manner; An ozone generator is used to supply ozone to the sludge oxidation tank. A microbubble disperser is used to generate ozone microbubbles and add them to the sludge oxidation tank; A circulating pump is installed outside the sludge oxidation tank. The outlet of the circulating pump is connected to the inlet of the jet mixer through a pipeline. It is used to extract the sludge mixture in the sludge oxidation tank and transport the sludge mixture to the jet mixer. The jet mixer is located outside the sludge oxidation tank. The air inlet of the jet mixer is connected to the air outlet of the ozone generator through a pipeline. It is used to receive ozone generated by the ozone generator and mix the ozone with the sludge mixture. The liquid outlet of the jet mixer is connected to the liquid inlet of the microbubble disperser through a pipeline. It is used to transport the sludge mixture containing ozone to the microbubble disperser.

4. The system as described in claim 3, characterized in that, The sludge pretreatment unit also includes: an ozone exhaust gas destroyer; The ozone exhaust gas destroyer is installed outside the sludge oxidation tank and is used to extract the exhaust gas from the top of the sludge oxidation tank through pipelines and destroy and decompose the ozone in the exhaust gas.

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