Sludge anaerobic digestion liquid treatment system and treatment method

Abstract

The invention provides a sludge anaerobic digestion solution treatment system and method, the treatment system comprises a digestion solution adjusting tank, a main reaction tank and a magnesium sulfate dissolving tank, the digestion solution adjusting tank is communicated with the main reaction tank through a digestion solution delivery pipe; the magnesium sulfate dissolving tank is communicated with the main reaction tank through a liquid medicine conveying pipe; the main reaction tank is communicated with the primary treatment front end of the sewage plant through a return pipe; a sludge discharge hole is formed in the bottom of the main reaction tank and is communicated with a sludge concentration tank of a sewage plant through a sludge discharge pipe. The sludge anaerobic digestion liquid treatment system is arranged before anaerobic digestion liquid is conveyed to the first-stage treatment front end of a sewage plant, liquid medicine is put into the sludge anaerobic digestion liquid and chemically reacts with high-concentration ammonia nitrogen pollutants in the sludge anaerobic digestion liquid, and finally precipitates are generated and separated out; therefore, the ammonia nitrogen concentration in the supernate is reduced, and the ammonia nitrogen treatment load of a sewage plant is greatly reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of sewage treatment, and particularly relates to a sludge anaerobic digestion liquid treatment system and a treatment method thereof. Background Art

[0002] In the biological treatment process of urban sewage, the generated sludge is mainly primary sedimentation sludge and excess activated sludge. When coagulation sedimentation is adopted, chemical sludge will also be generated. If it is not effectively treated and disposed of, it will cause serious pollution to the environment. At present, sludge anaerobic digestion is one of the mainstream processes for sludge treatment. After anaerobic digestion treatment, the sludge can be reduced, stabilized, rendered harmless, and recycled; while the anaerobic digestion liquid generated during the anaerobic digestion treatment is wastewater with a low carbon-nitrogen ratio, and its organic matter concentration is 500-1000 mg / L and the ammonia nitrogen concentration is 400-1800 mg / L. The existing treatment method is to transport it to the front end of the sewage treatment plant for re-treatment, which increases the ammonia nitrogen treatment load of the sewage treatment plant and easily leads to unqualified tail water discharge, thus causing secondary pollution. Summary of the Invention

[0003] To solve the above technical problems, the present invention provides a sludge anaerobic digestion liquid treatment system and a treatment method thereof, which greatly reduces the ammonia nitrogen treatment load of the sewage treatment plant.

[0004] The technical solution adopted by the present invention is: a sludge anaerobic digestion liquid treatment system, including a digestion liquid regulation tank, a main reaction tank, and a magnesium sulfate dissolution tank; wherein,

[0005] The digestion liquid regulation tank is communicated with the main reaction tank through a digestion liquid delivery pipe;

[0006] The magnesium sulfate dissolution tank is communicated with the main reaction tank through a liquid medicine delivery pipe;

[0007] The main reaction tank is communicated with the front end of the primary treatment of the sewage treatment plant through a reflux pipe;

[0008] A sludge discharge hole is provided at the bottom of the main reaction tank, and the sludge discharge hole is communicated with the sludge thickening tank of the sewage treatment plant through a sludge discharge pipe.

[0009] Further, a sludge discharge funnel is provided at the bottom of the main reaction tank, the sludge discharge hole is arranged at the lowest position of the sludge discharge funnel, and the sludge discharge hole is not less than 1.2 m from the ground.

[0010] Further, the main reaction tank is equipped with a stirring device, the stirring device includes a stirring paddle, the stirring paddle extends into the main reaction tank and is at least 0.5 m higher than the upper edge of the sludge discharge funnel.

[0011] Further, the outlet of the liquid medicine delivery pipe is at least 0.2 m higher than the highest designed liquid level of the main reaction tank.

[0012] Further, a grid is provided at the inlet end of the digestion liquid delivery pipe, the grid is not less than 0.3 meters above the bottom of the digestion liquid regulating tank, and the outlet end of the digestion liquid delivery pipe is at least 0.3 meters above the highest designed liquid level of the main reaction tank.

[0013] Further, a grid is provided at the inlet end of the reflux pipe, and the grid is 0.5 m - 0.8 m above the stirring paddle.

[0014] Further, a sludge volume monitoring device is provided inside the sludge discharge funnel.

[0015] Further, the digestion liquid regulating tank and the main reaction tank are respectively equipped with liquid detectors for detecting the water level and water quality in the tanks.

[0016] Further, a control system is further included. A transfer pump is provided on the digestion liquid delivery pipe, a chemical dosing pump is provided on the chemical liquid delivery pipe, a reflux pump is provided on the reflux pipe, and a sludge discharge pump is provided on the sludge discharge pipe. The control system is electrically connected to the stirring device, the sludge volume monitoring device, the liquid detector, the transfer pump, the chemical dosing pump, the reflux pump, and the sludge discharge pump respectively.

[0017] A method for treating sludge anaerobic digestion liquid uses the above-mentioned sludge anaerobic digestion liquid treatment system to treat sludge anaerobic digestion liquid, and includes the following steps:

[0018] A digestion liquid regulating tank is arranged at the front end of the primary treatment of the sewage treatment plant, and the volume of the digestion liquid regulating tank is determined based on the influent volume, sludge production volume, and digestion liquid reflux volume of the sewage treatment plant;

[0019] A main reaction tank is arranged between the digestion liquid regulating tank and the primary treatment;

[0020] A magnesium sulfate dissolution tank is arranged near the main reaction tank; the magnesium sulfate dissolution tank is connected to the main reaction tank through a chemical liquid delivery pipe;

[0021] A stirring device is installed at a set position of the main reaction tank;

[0022] The main reaction tank is connected to the front end of the primary treatment through a reflux pipe;

[0023] The magnesium sulfate dissolution tank is connected to the main reaction tank through a chemical liquid delivery pipe, and the main reaction tank is connected to the sludge thickening tank of the sewage treatment plant through a sludge discharge pipe;

[0024] A liquid detector is installed, and its probe extends into set positions of the digestion liquid regulating tank and the main reaction tank respectively;

[0025] The liquid detector detects the water level and water quality in the digestion liquid regulation tank and the main reaction tank, and transmits the water level detection result and the water quality detection result to the control system;

[0026] Based on the water level detection result in the digestion liquid regulation tank, the control system controls the opening and closing of the transfer pump; and based on the water quality detection result in the main reaction tank, the control system controls the opening and closing of the chemical dosing pump;

[0027] Based on the water level detection result in the main reaction tank, the control system controls the opening and closing of the stirring device and the closing of the reflux pump; and based on the water quality detection result in the main reaction tank, the control system controls the opening of the reflux pump;

[0028] Based on the detection result of the sludge quantity monitoring device, the control system controls the opening and closing of the sludge discharge pump.

[0029] The advantages and positive effects of the present invention are as follows: By arranging the sludge anaerobic digestion liquid treatment system before the anaerobic digestion liquid is transported to the front end of the primary treatment of the sewage treatment plant, and by putting the liquid medicine into the sludge anaerobic digestion liquid in the main reaction tank, a chemical reaction occurs with the high-concentration ammonia nitrogen pollutants in the sludge anaerobic digestion liquid, and finally precipitates are generated and separated out, thereby reducing the ammonia nitrogen concentration in the supernatant. Subsequently, the supernatant is transported to the front end of the primary treatment through the reflux pipe, greatly reducing the ammonia nitrogen treatment load of the sewage treatment plant; By setting up a sludge discharge funnel and connecting it to the sludge thickening tank of the sewage treatment plant, the automatic centralized collection and discharge of the precipitate are effectively realized, ensuring the efficient operation and environmental friendliness of the main reaction tank, and avoiding operation problems and maintenance difficulties caused by the accumulation of the precipitate. Description of the Drawings

[0030] Figure 1 is a structural schematic diagram of a specific embodiment of the present invention.

[0031] In the figure:

[0032] 1. Main reaction tank; 2. Sludge discharge pipe; 3. Sludge discharge pump; 4. Sludge discharge hole; 5. Stirring paddle; 6. Grid; 7. Reflux pipe; 8. Reflux pump; 9. Driving mechanism; 10. Magnesium sulfate dissolution tank; 11. Chemical dosing pump; 12. Sludge quantity monitor; 13. Transfer pump; 14. Control system; 15. Liquid detector; 16. Digestion liquid regulation tank. Detailed Embodiments

[0033] The following describes the embodiments of the present invention with reference to the drawings.

[0034] An embodiment of the present invention provides a sludge anaerobic digestion liquid treatment system for treating the anaerobic digestion liquid generated during the sludge anaerobic digestion process. Compared with the prior art method of directly transporting the anaerobic digestion liquid to the front end of the sewage treatment plant for re - treatment, it significantly reduces the ammonia nitrogen treatment load of the sewage treatment plant, avoids the situation of unqualified tail water discharge, and thus effectively avoids secondary pollution.

[0035] As Figure 1 shown, an embodiment of the present invention provides a sludge anaerobic digestion liquid treatment system, including a digestion liquid regulation tank 16, a main reaction tank 1, and a magnesium sulfate dissolution tank 10. Among them, the digestion liquid regulation tank 16 is connected to the main reaction tank 1 through a digestion liquid delivery pipe; the magnesium sulfate dissolution tank 10 is connected to the main reaction tank 1 through a liquid medicine delivery pipe; the main reaction tank 1 is connected to the front end of the primary treatment of the sewage treatment plant through a reflux pipe 7; a sludge discharge hole 4 is provided at the bottom of the main reaction tank 1, and the sludge discharge hole 4 is connected to the sludge thickening tank of the sewage treatment plant through a sludge discharge pipe 2.

[0036] Among them, the digestion liquid regulation tank 16 is used to store the sludge anaerobic digestion liquid. The sludge anaerobic digestion liquid is generated when the sewage treatment plant adopts the sludge anaerobic digestion process for sewage treatment. The sludge anaerobic digestion technology is a biological treatment process in which microorganisms decompose organic matter in sludge under anaerobic conditions. The sludge anaerobic digestion liquid contains high concentrations of ammonia nitrogen, organic matter, and suspended solids, and needs to be further treated to meet the discharge or reuse standards. Therefore, the volume of the digestion liquid regulation tank 16 in this application is adapted to the amount of sludge anaerobic digestion liquid generated in the sludge anaerobic digestion process of the sewage treatment plant and is connected to the sludge anaerobic digestion process, so as to facilitate the timely transfer and storage of the sludge anaerobic digestion liquid into the digestion liquid regulation tank.

[0037] The above - mentioned magnesium sulfate dissolution tank 10 stores a liquid medicine, and the liquid medicine is a chemical substance containing magnesium ions such as magnesium sulfate. In this technical solution, the sludge anaerobic digestion liquid is input into the main reaction tank 1 through the digestion liquid delivery pipe, and the liquid medicine in the magnesium sulfate dissolution tank 10 is put into the sludge anaerobic digestion liquid in the main reaction tank 1 through the liquid medicine delivery pipe. The liquid medicine reacts chemically with the high - concentration ammonia nitrogen pollutants in the sludge anaerobic digestion liquid and finally precipitates out, thereby reducing the ammonia nitrogen concentration in the supernatant. Subsequently, the supernatant is transported to the front end of the primary treatment through the reflux pipe 7, significantly reducing the ammonia nitrogen treatment load of the sewage treatment plant; the precipitate in the main reaction tank 1 is mainly struvite, which is discharged through the sludge discharge hole 4 to the sludge thickening tank of the sewage treatment plant for further treatment and discharge.

[0038] In the above - mentioned embodiment, the principle of the chemical reaction between the liquid medicine and the sludge anaerobic digestion liquid is as follows:

[0039]

[0040] In this embodiment, a sludge discharge funnel is provided at the bottom of the main reaction tank 1, and a sludge discharge hole 4 is arranged at the lowest position of the sludge discharge funnel. The sludge discharge hole 4 is not less than 1.2 m from the ground. By providing the sludge discharge funnel, the precipitate generated by the chemical reaction can be deposited by gravity to the sludge discharge hole 4 at the lowest position of the funnel, thus effectively avoiding the accumulation of the precipitate; the setting position of the sludge discharge hole 4 and the height from the ground ensure the smooth discharge of the precipitate without affecting the normal operation of the main reaction tank 1; by providing the sludge discharge funnel and the sludge discharge hole 4, the automatic centralized collection and discharge of the precipitate are effectively realized, ensuring the efficient operation and environmental friendliness of the main reaction tank 1, and avoiding operation problems and maintenance difficulties caused by the accumulation of the precipitate.

[0041] In this embodiment, the main reaction tank 1 is equipped with a stirring device. The stirring device includes a stirring paddle 5. The stirring paddle 5 extends into the main reaction tank 1 and is at least 0.5 m higher than the upper edge of the sludge discharge funnel. By providing the stirring device, the chemical reaction occurring in the main reaction tank 1 is made more sufficient and the reaction rate is accelerated. The stirring paddle 5 is arranged at least 0.5 m above the upper edge of the sludge discharge funnel, which can not only ensure the best stirring effect but also avoid disturbing the precipitate in the sludge discharge funnel, affecting the discharge of the precipitate and the water quality of the supernatant.

[0042] In the above embodiment, the stirring device is further provided with a driving mechanism 9. The driving mechanism 9 is arranged outside the main reaction tank 1 and is connected to the stirring paddle 5 through a rotating shaft to avoid the adverse effects of the liquid in the main reaction tank 1 on the operation and maintenance of the driving mechanism 9, and improve the stability and service life of the device operation.

[0043] In this embodiment, the outlet of the liquid medicine delivery pipe is at least 0.2 m higher than the highest designed liquid level of the main reaction tank 1. This design enables the liquid medicine to be released from the high-level outlet, obtain initial kinetic energy relying on gravitational potential energy, and quickly diffuse into the main reaction tank 1, increasing the contact area between the liquid medicine and the anaerobic digestion liquid of the sludge in the tank, and also avoiding the accumulation of the liquid medicine at the bottom of the tank or in a local area, preventing uneven reactions or side reactions caused by too large a concentration gradient; in addition, this setting can also prevent the anaerobic digestion liquid of the sludge in the tank from flowing back into the liquid medicine delivery pipe or the magnesium sulfate dissolution tank 10.

[0044] In this embodiment, a grid 6 is provided at the inlet end of the digestion liquid delivery pipe. The grid 6 is not less than 0.3 m above the bottom of the digestion liquid regulation tank 16, and the outlet end of the digestion liquid delivery pipe is at least 0.3 m higher than the highest designed liquid level of the main reaction tank 1. The grid mainly plays a filtering role to avoid the entry of particulate matters such as sediment into the main reaction tank 1; through the above technical solution, the heights of the inlet end and the outlet end of the digestion liquid delivery pipe are precisely set so that it can not only adapt to the liquid height in the digestion liquid regulation tank 16 but also adapt to the liquid height in the main reaction tank 1, enabling it to play its role more effectively in actual use to ensure the normal operation of the overall system.

[0045] Further, in this embodiment, a grid 6 is provided at the inlet end of the reflux pipe 7, and the grid 6 is 0.5 m - 0.8 m higher than the upper edge of the stirring paddle 5. After the complete reaction in the main reaction tank 1, the upper clear liquid and the lower sediment form a layer. The inventor of the present application found that when the inlet end of the reflux pipe 7 is arranged 0.5 m - 0.8 m above the stirring paddle 5, while avoiding interfering with the operation of the stirring paddle 5, the action range of the inlet end of the reflux pipe 7 can be effectively controlled to make it adapted to the height of the upper clear liquid.

[0046] Further, in the embodiment of the present application, a sludge amount monitoring device 12 is provided in the sludge discharge funnel, which can detect the cumulative height of the sediment in the sludge discharge funnel in real time, provide an effective basis for the discharge of the sediment, and ensure the normal and stable operation of the system.

[0047] Further, in the embodiment of the present application, a liquid detector 15 is respectively arranged in the digestion liquid adjustment tank 16 and the main reaction tank 1 for detecting the water level and water quality in the tank. Through the liquid detector 15, the water level and water quality in the digestion liquid adjustment tank 16 and the main reaction tank 1 can be monitored in real time, so as to control the transportation of the sludge anaerobic digestion liquid and the reflux of the upper clear liquid after the reaction is completed, and realize precise and automatic control.

[0048] Specifically, the liquid detector 15 includes a data acquisition and processing unit, a detection module and a communication module. The detection module includes a water level sensor assembly and a water quality sensor assembly. The detection probes of the water level sensor assembly and the water quality sensor assembly are both arranged at the set positions of the digestion liquid adjustment tank 16 and the main reaction tank 1. The detection probe of the water quality sensor assembly can accurately detect the ammonia nitrogen concentration in the liquid, and the detection probe of the water level sensor assembly can detect the height of the liquid in the tank in real time. After receiving the detection results transmitted by the detection probe, the data acquisition and processing unit converts them into digital signals, calculates the parameter values, and transmits them to the control system 14.

[0049] Further, in the above embodiments, a control system 14 is further included. The control system 14 presets the liquid level control parameters and liquid quality control parameters of the digestion liquid regulating tank 16 and the main reaction tank 1, and performs comparison and analysis based on the detection results transmitted by the liquid detector 15 to control the transportation of the sludge anaerobic digestion liquid and the reflux of the supernatant; specifically, a transfer pump 13 is arranged on the digestion liquid delivery pipe, a chemical dosing pump 11 is arranged on the chemical liquid delivery pipe, a reflux pump 8 is arranged on the reflux pipe 7, and a sludge discharge pump 3 is arranged on the sludge discharge pipe 2. The control system 14 is electrically connected to the stirring device, the sludge quantity monitoring device 12, the liquid detector 15, the transfer pump 13, the chemical dosing pump 11, the reflux pump 8, and the sludge discharge pump 3 respectively, and controls the operation of the stirring device, the transfer pump 13, the chemical dosing pump 11, the reflux pump 8, and the sludge discharge pump 3 based on the detection results of the liquid detector 15 and the detection results of the sludge quantity monitoring device 12 to achieve the automatic operation of the system.

[0050] The present application also proposes a method for treating sludge anaerobic digestion liquid, which adopts the above-mentioned sludge anaerobic digestion liquid treatment system, and includes the following steps:

[0051] S1. A digestion liquid regulating tank 16 is arranged at the front end of the primary treatment of the sewage treatment plant. The volume of the digestion liquid regulating tank 16 is determined based on the influent volume, sludge production volume, and digestion liquid reflux volume of the sewage treatment plant;

[0052] S2. A main reaction tank 1 is arranged between the digestion liquid regulating tank 16 and the primary treatment;

[0053] Preferably, the main reaction tank 1 is arranged adjacent to the digestion liquid regulating tank 16. A sludge discharge funnel is arranged at the bottom of the main reaction tank 1, so that the sludge discharge hole 4 at the lowest part of the sludge discharge funnel is not less than 1.2 m away from the ground;

[0054] Further, the volume of the main reaction tank 1 is adapted to the volume of the digestion liquid regulating tank 16 and the reaction rate of the chemical liquid and the sludge anaerobic digestion liquid; a sludge quantity monitoring device 12 is arranged at the set position of the sludge discharge funnel.

[0055] S3. A magnesium sulfate dissolving tank 10 is arranged adjacent to the main reaction tank 1, and the magnesium sulfate dissolving tank 10 is connected to the main reaction tank 1 through a chemical liquid delivery pipe;

[0056] Specifically, when installing the chemical liquid delivery pipe, its outlet is at least 0.2 m higher than the highest designed liquid level of the main reaction tank 1; a chemical dosing pump 11 is arranged on the chemical liquid delivery pipe.

[0057] S4. A stirring device is installed at the set position of the main reaction tank 1;

[0058] Specifically, the stirring device includes a stirring paddle 5 and a driving mechanism 9 for driving the rotation of the stirring paddle 5. The driving mechanism 9 is arranged outside the main reaction tank 1 and is connected to the stirring paddle 5 through a rotating shaft. The stirring paddle 5 is arranged at least 0.5 m above the upper edge of the sludge discharge funnel. Preferably, the clear distance between the stirring paddle and the wall of the main reaction tank 1 is 0.2 - 0.3 m.

[0059] S5. Connect the main reaction tank 1 and the front end of the primary treatment through the reflux pipe 7.

[0060] Specifically, the reflux pipe 7 is equipped with a reflux pump 8. The inlet end of the reflux pipe 7 is arranged in the main reaction tank 1 and is provided with a grid 6, and the grid 6 is 0.5 m - 0.8 m higher than the upper edge of the stirring paddle 5. The outlet end of the reflux pipe 7 is communicated with the front end of the primary treatment of the sewage treatment plant.

[0061] S6. Connect the magnesium sulfate dissolution tank 10 and the main reaction tank 1 through a liquid medicine delivery pipe, and connect the main reaction tank 1 and the sludge thickening tank of the sewage treatment plant through a sludge discharge pipe 2.

[0062] Specifically, the liquid medicine delivery pipe is equipped with a delivery pump. The inlet end of the liquid medicine delivery pipe is arranged in the digestion liquid adjustment tank 16, and a grid 6 is provided at its end. The grid 6 is not less than 0.3 m higher than the bottom of the digestion liquid adjustment tank 16, and the distance from the pool wall is not less than 0.5 m. The outlet end of the digestion liquid delivery pipe is arranged in the main reaction tank 1 and is at least 0.3 m higher than the highest designed liquid level of the main reaction tank 1.

[0063] S7. Install a liquid detector 15 so that its probe extends into the set positions of the digestion liquid adjustment tank 16 and the main reaction tank 1 respectively.

[0064] S8. The liquid detector 15 detects the water level and water quality in the digestion liquid adjustment tank 16 and the main reaction tank 1, and transmits the water level detection result and the water quality detection result to the control system 14.

[0065] S9. The control system 14 controls the opening and closing of the transfer pump 13 based on the water level detection result in the digestion liquid adjustment tank 16; and controls the opening and closing of the chemical dosing pump 11 based on the water quality detection result in the main reaction tank 1.

[0066] Specifically, when the water level in the digestion liquid adjustment tank 16 reaches the set transfer water level, the control system 14 controls the transfer pump 13 to start, and the anaerobic digestion liquid of the sludge is transferred from the digestion liquid adjustment tank 16 to the main reaction tank 1; when the water level in the digestion liquid adjustment tank 16 reaches the set lowest water level, the control system 14 controls the transfer pump 13 to close, and the anaerobic digestion liquid of the sludge stops being transferred from the digestion liquid adjustment tank 16 to the main reaction tank 1.

[0067] When the water quality detection result in the main reaction tank 1 meets the requirements of the preset reflux parameters, the control system 14 controls the reflux pump 8 to start, and the sludge anaerobic digestion liquid is transferred from the main reaction tank 1 to the primary treatment of the sewage treatment plant; when the water quality detection result in the main reaction tank 1 meets the requirements of the preset reaction parameters, the control system 14 controls the chemical dosing pump 11 to start, and the liquid medicine is transferred from the magnesium sulfate dissolution tank 10 into the main reaction tank 1; and based on the water level detection result and the water quality detection result in the main reaction tank 1, the control system 14 can determine the amount of liquid medicine to be put in.

[0068] S10. Based on the water level detection result in the main reaction tank 1, the control system 14 controls the opening, closing of the stirring device and the closing of the reflux pump 8; and based on the water quality detection result in the main reaction tank 1, the control system 14 controls the reflux pump 8 to start.

[0069] Specifically, when the water level in the main reaction tank 1 reaches the set stirring water level, the control system 14 controls the stirring device to start, the stirring paddle stirs the liquid in the main reaction tank 1, and after stirring for the set time, the control system 14 controls the stirring device to close, and this time is preferably 5 - 10 min; when the water level in the main reaction tank 1 reaches the set minimum water level, the control system 14 controls the reflux pump 8 to close, and stops the supernatant from being transferred to the primary treatment of the sewage treatment plant;

[0070] When the water quality in the main reaction tank 1 reaches the set return water quality, the control system 14 controls the reflux pump 8 to start, and transfers the supernatant to the primary treatment of the sewage treatment plant;

[0071] S11. Based on the detection result of the sludge amount monitoring device 12, the control system 14 controls the opening and closing of the sludge discharge pump 3.

[0072] Specifically, when the sludge amount monitoring device 12 detects that the sediment in the sludge discharge funnel reaches the set discharge height, the control system 14 controls the sludge discharge pump 3 to start, and the sediment is discharged to the sewage treatment plant sludge thickening tank through the sludge discharge pipe 2; when the sludge amount monitoring device 12 detects that the sediment in the sludge discharge funnel reaches the set minimum height, the control system 14 controls the sludge discharge pump 3 to close.

[0073] It can be understood that the above steps S9, S10 and S11 operate independently according to the set program and do not interfere with each other. Some steps can be set to be synchronized or carried out successively as needed, and all can achieve automatic control.

[0074] The above has described the embodiments of the present invention in detail, but the content described is only the preferred embodiments of the present invention and cannot be considered as limiting the scope of implementation of the present invention. All equivalent changes and improvements made according to the scope of the application of the present invention should still fall within the scope covered by the patent of the present invention.

Claims

1. A sludge anaerobic digestion liquid treatment system, characterized in that: It includes a digestive juice regulating tank, a main reaction tank and a magnesium sulfate dissolving tank; among them, the digestive juice regulating tank is communicated with the main reaction tank through a digestive juice delivery pipe; the magnesium sulfate dissolving tank is communicated with the main reaction tank through a liquid medicine delivery pipe; the main reaction tank is communicated with the front end of the primary treatment of the sewage treatment plant through a reflux pipe; a sludge discharge hole is arranged at the bottom of the main reaction tank, and the sludge discharge hole is communicated with the sludge thickening tank of the sewage treatment plant through a sludge discharge pipe.

2. The sludge anaerobic digestion liquid treatment system according to claim 1, characterized in that: a sludge discharge funnel is arranged at the bottom of the main reaction tank, the sludge discharge hole is arranged at the lowest position of the sludge discharge funnel, and the sludge discharge hole is not less than 1.2 m away from the ground.

3. The sludge anaerobic digestion liquid treatment system according to claim 1 or 2, characterized in that: the main reaction tank is equipped with a stirring device, the stirring device includes a stirring paddle, the stirring paddle extends into the main reaction tank and is at least 0.5 m higher than the upper edge of the sludge discharge funnel.

4. The sludge anaerobic digestion liquid treatment system according to claim 3, wherein: the outlet of the liquid medicine delivery pipe is at least 0.2 m higher than the highest designed liquid level of the main reaction tank.

5. The sludge anaerobic digestion liquid treatment system according to claim 5, wherein: a grid is arranged at the inlet end of the digestive juice delivery pipe, the grid is not less than 0.3 m higher than the bottom of the digestive juice regulating tank, and the outlet end of the digestive juice delivery pipe is at least 0.3 m higher than the highest designed liquid level of the main reaction tank.

6. The sludge anaerobic digestion liquid treatment system according to claim 4 or 5, characterized in that: a grid is arranged at the inlet end of the reflux pipe, and the grid is 0.5 m - 0.8 m higher than the stirring paddle.

7. The sludge anaerobic digestion liquid treatment system according to claim 3, characterized in that: a sludge quantity monitoring device is arranged in the sludge discharge funnel.

8. The sludge anaerobic digestion liquid treatment system according to claim 7, wherein: the digestive juice regulating tank and the main reaction tank are respectively equipped with liquid detectors for detecting the water level and water quality in the tanks.

9. The sludge anaerobic digestion liquid treatment system according to claim 8, wherein: It further includes a control system. A transfer pump is arranged on the digestive juice delivery pipe, a dosing pump is arranged on the liquid medicine delivery pipe, a reflux pump is arranged on the reflux pipe, a sludge discharge pump is arranged on the sludge discharge pipe, and the control system is electrically connected to the stirring device, the sludge quantity monitoring device, the liquid detectors, the transfer pump, the dosing pump, the reflux pump and the sludge discharge pump respectively.

10. A method for treating anaerobic digestion liquid of sludge, characterized in that, Using the sludge anaerobic digestive juice treatment system described in any one of claims 1 - 9 to treat sludge anaerobic digestive juice, including the following steps: set up a digestive juice regulating tank at the front end of the primary treatment of the sewage treatment plant, and the volume of the digestive juice regulating tank is determined based on the influent volume, sludge production volume and digestive juice reflux volume of the sewage treatment plant; set up a main reaction tank between the digestive juice regulating tank and the primary treatment; set up a magnesium sulfate dissolving tank near the main reaction tank; connect the magnesium sulfate dissolving tank and the main reaction tank through a liquid medicine delivery pipe; install a stirring device at the set position of the main reaction tank; connect the main reaction tank and the front end of the primary treatment through a reflux pipe; connect the magnesium sulfate dissolving tank and the main reaction tank through a liquid medicine delivery pipe, and connect the main reaction tank and the sludge thickening tank of the sewage treatment plant through a sludge discharge pipe; install liquid detectors, and make their probes extend into the set positions of the digestive juice regulating tank and the main reaction tank respectively; the liquid detectors detect the water level and water quality in the digestive juice regulating tank and the main reaction tank, and transmit the water level detection result and water quality detection result to the control system; the control system controls the opening and closing of the transfer pump based on the water level detection result in the digestive juice regulating tank; and controls the opening and closing of the dosing pump based on the water quality detection result in the main reaction tank; The control system controls the opening and closing of the stirring device and the closing of the reflux pump based on the water level detection result in the main reaction tank; and controls the opening of the reflux pump based on the water quality detection result in the main reaction tank. The control system controls the opening and closing of the sludge discharge pump based on the detection result of the sludge volume monitoring device.

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