Activated sludge dewatering device and method based on piezoelectric effect

Abstract

The invention discloses an activated sludge dewatering device and method based on a piezoelectric effect, and relates to the technical field of dewatering equipment. The mixing mechanism is arranged at the top of the equipment main body and is used for mixing a piezoelectric material and activated sludge; the filter pressing and dewatering mechanism is arranged in the equipment main body, is used for extruding and dewatering a mixture of the piezoelectric material and the activated sludge and can generate electromagnetic force; the sewage recycling tank is arranged at the bottom of the equipment main body; the filter-pressing dehydration mechanism is communicated with the mixing mechanism, and the mixed piezoelectric material and activated sludge mixture enters the filter-pressing dehydration mechanism from the mixing mechanism for filter-pressing dehydration; the filter-pressing dehydration mechanism is communicated with a sewage recovery box, and dehydrated water enters the sewage recovery box. The combined action of mechanical pressure, electroosmosis effect, electromagnetic force, electric heating and magnetic-to-electric effect is combined, the dehydration effect is more remarkable, and energy consumption is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of dehydration equipment, and in particular to an activated sludge dehydration device and method based on piezoelectric effect. Background Art

[0002] The huge amount of urban sludge production has caused serious environmental problems. If the sewage sludge is not properly disposed of and randomly piled up, it may cause serious pollution risks. In order to reduce the volume of sludge and facilitate subsequent transportation and treatment, it is necessary to remove most of the water in the sludge through dehydration. In order to achieve deep dehydration of sludge, it is necessary not only to dehydrate the sludge under high pressure, but also to use physical, chemical or biological conditioning methods to improve the sludge dehydration capacity, reduce the mass and volume of sludge, and facilitate the subsequent treatment and utilization of sludge resources. In recent years, researchers have conducted a lot of research on dehydration processes such as freeze-thaw, coagulation, acid or alkali treatment, ultrasonic pretreatment, and microwave treatment. These traditional methods are all dehydration with a single physical field.

[0003] However, a single physical field such as mechanical filter press can no longer meet the requirements for sludge dehydration. Therefore, seeking coupled dehydration between multiple physical fields is an important means to solve the problem. At the same time, it also solves the problems of high energy consumption and insufficient control accuracy that may exist in the existing multi-field coupled sludge dehydration technology.

[0004] In addition, activated sludge is the most difficult sludge to dewater due to its extracellular polymers and charged characteristics. When dehydrating it, there are also problems: 1. Mechanical pressure and thermal drying require a lot of energy, resulting in high operating costs; 2. Lack of intelligent control means, it is difficult to dynamically adjust the treatment parameters according to the specific characteristics of the sludge, resulting in unstable dehydration effects; 3. Some technologies may involve the use of chemical agents, which can easily cause secondary pollution and have a negative impact on the environment. Summary of the invention

[0005] The purpose of the present invention is to provide an activated sludge dewatering device and method based on piezoelectric effect, which realizes efficient and energy-saving sludge dewatering through the comprehensive action of mechanical pressure, electroosmotic effect, electromagnetic force, electric heating and magnetoelectric effect.

[0006] To achieve the above object, the present invention provides the following technical solutions: The activated sludge dewatering device based on the piezoelectric effect comprises an equipment body, a mixing mechanism arranged on the top of the equipment body for mixing piezoelectric material and activated sludge, a filter press dewatering mechanism arranged in the equipment body for squeezing and dehydrating the piezoelectric material and activated sludge mixture and generating electromagnetic force, and a sewage recovery tank arranged at the bottom of the equipment body, wherein the filter press dewatering mechanism is connected with the mixing mechanism, and the mixed piezoelectric material and activated sludge mixture enters the filter press dewatering mechanism from the mixing mechanism for filter press dewatering; and the filter press dewatering mechanism is connected with the sewage recovery tank, and the dewatered water enters the sewage recovery tank; when the filter press dewatering mechanism dehydrates, the piezoelectric material and activated sludge mixture are compressed to generate a piezoelectric effect, so that the water molecules in the sludge carry positive and negative charges, and the activated sludge is dehydrated by the electromagnetic force generated by the filter press dewatering mechanism in combination with the pressure.

[0007] Compared with the prior art, the present invention has the following beneficial effects: The invention combines the comprehensive effects of mechanical pressure, electroosmotic effect, electromagnetic force, electric heating and magnetoelectric effect, so the dehydration effect is more significant and energy consumption is saved. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a schematic diagram of the structure of the activated sludge dewatering device based on the piezoelectric effect.

[0009] Figure 2 A cross-sectional view of an activated sludge dewatering device based on the piezoelectric effect.

[0010] Figure 3 It is a schematic diagram of the structure of the filter press dewatering mechanism in the activated sludge dewatering device based on the piezoelectric effect.

[0011] Figure 4 The present invention is a flow chart of the method for using the activated sludge dewatering device based on the piezoelectric effect. DETAILED DESCRIPTION

[0012] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0013] See also Figures 1 to 4In an embodiment of the present invention, an activated sludge dewatering device based on piezoelectric effect includes an equipment body 1, a mixing mechanism 2 arranged on the top of the equipment body 1 for mixing piezoelectric material and activated sludge, a filter press dewatering mechanism 3 that can generate electromagnetic force and is arranged in the equipment body 1 for extruding and dehydrating the piezoelectric material and activated sludge mixture, and a sewage recovery tank 4 arranged at the bottom of the equipment body 1, wherein the filter press dewatering mechanism 3 is connected to the mixing mechanism 2, and the mixed piezoelectric material and activated sludge mixture enters the filter press dewatering mechanism 3 from the mixing mechanism 2 for filter press dehydration; and the filter press dewatering mechanism 3 is connected to the sewage recovery tank 4, and the dewatered water enters the sewage recovery tank 4; when the filter press dewatering mechanism 3 dehydrates, the piezoelectric material and activated sludge mixture are pressurized to generate a piezoelectric effect, so that the water molecules in the sludge carry positive and negative charges, and the electromagnetic force generated by the filter press dewatering mechanism 3 cooperates with the pressure to dehydrate the activated sludge.

[0014] The invention combines the comprehensive effects of mechanical pressure, electroosmotic effect, electromagnetic force, electric heating and magnetoelectric effect, so the dehydration effect is more significant and energy consumption is saved.

[0015] The filter pressing and dehydration mechanism 3 includes a central cavity arranged in the equipment body 1, the inlet of the central cavity is connected to the outlet of the mixing mechanism 2, and the outlet of the central cavity is connected to the sewage recovery tank 4. Two pressing plates 31 arranged side by side are arranged in the central cavity, one of which is fixed to the inner wall of the equipment body 1, and the other is driven to move by a press 32 arranged in the equipment body 1 to squeeze and dehydrate the mixture in the central cavity. A filter cloth is covered on the pressing plate 31.

[0016] It should be noted that a power supply and a control system are provided in the main body 1 of the device, which are used to control the operation of the press 32 and various electrical components in the device.

[0017] Annular permanent magnets and electrodes 34 are fixed on the sides of the two pressing plates 31 that are away from each other. Electromagnetic coils 33 are wound around the two permanent magnets. The electrodes 34 are connected to an external power supply through wires. When the power is turned on, the electromagnetic coils 33 generate electromagnetic force. The electrodes 34 connect the pressing plates 31 and the power supply to form a passage through the sludge water. When the power is turned on, the electromagnetic coils 33 generate electromagnetic force and realize electroosmosis.

[0018] It should be noted that the permanent magnets on the two pressure plates 31 are arranged in the same direction to ensure the same direction of the magnetic field, so that the magnetic fields of the two permanent magnets do not cancel each other out. During the dehydration process, when the charged water passes through the space between the permanent magnets, it can cut the magnetic field between the two permanent magnets and realize a certain amount of power generation function, thereby improving the practicality of the present application.

[0019] The electrode 34 on the fixed pressing plate 31 is connected to the positive pole of the power supply, and the pressing plate 31 moved by the press 32 is connected to the negative pole of the current, ensuring that the electroosmosis and mechanical pressure work together; this design allows the water to flow toward the fixed pressing plate 31 in a directional manner and be discharged through the bottom, while the movable pressing plate 31 further compresses the sludge volume by increasing the mechanical pressure, and cooperates with the negative current to promote the dehydration process of the sludge.

[0020] The output end of the piezoelectric material feeder 21 is connected to the sludge stirring component 22. The piezoelectric material feeder 21 feeds the piezoelectric material into the sludge stirring component 22, and the sludge stirring component 22 stirs and mixes the piezoelectric material and the sludge. A sludge feeding port 23 is provided at the bottom of the sludge stirring component 22, and the sludge feeding port 23 is connected to the filter press dewatering mechanism 3. The mixed piezoelectric material and sludge mixture enters the filter press dewatering mechanism 3 through the sludge feeding port 23.

[0021] The piezoelectric material dispenser 21 is provided with a weight sensor for detecting and controlling the amount of piezoelectric material put into the sludge stirring component 22 .

[0022] The sludge delivery port 23 is provided with a solenoid valve.

[0023] The method for using the activated sludge dewatering device based on the piezoelectric effect comprises the following steps: Step 1: transport the piezoelectric material and sludge in the piezoelectric material dispenser 21 to the mixing mechanism 2 for thorough mixing; Step 2: After the mixing is completed, the mixture is transported from the mixing mechanism 2 to the filter pressing and dehydration mechanism 3 for filter pressing, and at the same time, a piezoelectric effect is generated, and dehydration is performed in conjunction with the generated electromagnetic force; Step 3: The separated water enters the sewage recovery tank 4 for recovery.

[0024] When the piezoelectric material is added in step 1, the amount of the piezoelectric material added is detected by a weight sensor.

[0025] The piezoelectric material is MoS2, and its ratio to sludge is 1-5:100.

[0026] In step 2, after the piezoelectric material and the sludge mixture are transported to the filter press dehydration mechanism 3, the solenoid valve of the sludge delivery port 23 is closed to prevent the external environment from interfering with the dehydration process.

[0027] It should be noted that the pressure range of the pressing plate 31 is between 0.1-8 MPa and is adjustable. Under the mechanical pressure, MoS2 generates a piezoelectric field to induce polar molecules (i.e., water and hydroxyl radicals) to adsorb on its surface, generating hydroxyl radicals ·OH and superoxide anions ·O. 2-The strong oxidizing property of ROS can oxidize the colloidal structure of sludge, break down extracellular polymers (EPS), and release bound water. The piezoelectric effect and residual piezoelectric field effect of MoS2 can realize the electrical neutralization of sludge charge and improve the dewatering performance of sludge. MoS2 not only acts as a catalyst but also plays a role in skeleton construction, establishing pore channels for water discharge in sludge. At the same time, the sludge filtrate is detected by three-dimensional fluorescence spectroscopy technology to characterize the changes in EPS inside the sludge, the Zeta potential of the sludge is measured by a potentiometer, and the intracellular water, adsorbed water, interstitial water and free water content of the sludge are measured by a synchronous thermal analyzer to evaluate the destruction of extracellular polymers and the release of bound water in the sludge.

[0028] In addition, the pressing plate 31 in the central cavity is equipped with an electrode 34, and the electromagnetic coil 33 surrounding the cavity is used to generate electromagnetic force and realize electroosmosis. Under the action of the pressing plate 31 and the filter cloth, the sludge is subjected to dual treatment of mechanical pressure and electroosmosis. The permanent magnet on the pressing plate 31 generates an electromagnetic field through the electromagnetic coil 33, further enhancing the compression effect on the sludge. At the same time, the power supply of the electromagnetic coil 33 generates heat, which assists the evaporation of water in the sludge and further reduces the water content of the sludge.

[0029] Finally, when the pressing plate 31 contacts the mud cake, the permanent magnet attracts the charged particles and water molecules in the sludge under the action of the electromagnetic field, thereby enhancing the effect of sludge dehydration. In the process of compressing the sludge by the pressing plate 31, the distance sensor monitors the distance between the movable pressing plate 31 and the fixed pressing plate 31 in real time. During the specific operation, the thickness of the mud cake is 3-10 mm, and the data is fed back to the control system. The control system adjusts the voltage according to the feedback data to achieve precise control of the constant voltage gradient. The mechanical pressure changes with the distance between the pressing plate 31 and the sludge, and the pressure range is 0.1-8Mpa; in the constant voltage gradient dehydration mode, the voltage gradient range is 10-50V / cm. In addition, the electromagnetic coil 33 will generate a certain amount of heat when it is energized. This heat, as an auxiliary heating source, can accelerate the evaporation of water in the sludge and further reduce the water content of the sludge. After multiple dehydration processes, the sludge recovery box is extracted from the cavity to recover the dehydrated sludge, and the sewage is recovered by the sewage recovery tank 4 at the bottom, and the entire treatment process is completed.

[0030] Based on the above principle, the present application conducted an experiment to compare the water content of the initial sludge and the piezoelectric material mixed sludge under different dehydration pressures within 30 minutes. The specific data are shown in Table 1: Table 1 The experimental data of the comparison of the water content of the initial sludge and the piezoelectric material mixed sludge when the mechanical pressure is 6MPa and changes with time are shown in Table 2: Table 2 Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art may still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention, and the contents not described in detail in this specification shall belong to the prior art known to professional and technical personnel in the field.

Claims

1. An activated sludge dewatering device based on piezoelectric effect, characterized in that: The invention comprises an equipment body (1), a mixing mechanism (2) arranged at the top of the equipment body (1) for mixing a piezoelectric material and activated sludge, a filter press dehydration mechanism (3) arranged in the equipment body (1) for extruding and dehydrating the piezoelectric material and activated sludge mixture and capable of generating electromagnetic force, and a sewage recovery tank (4) arranged at the bottom of the equipment body (1), wherein the filter press dehydration mechanism (3) is connected to the mixing mechanism (2), and the mixed piezoelectric material and activated sludge mixture enters the filter press dehydration mechanism (3) from the mixing mechanism (2) for filter press dehydration; and the filter press dehydration mechanism (3) is connected to the sewage recovery tank (4), and the dehydrated water enters the sewage recovery tank (4); when the filter press dehydration mechanism (3) dehydrates, the piezoelectric material and activated sludge mixture is compressed to generate a piezoelectric effect, so that water molecules in the sludge carry positive and negative charges, and the activated sludge is dehydrated by the electromagnetic force generated by the filter press dehydration mechanism (3) in combination with the pressure.

2. The activated sludge dewatering device based on piezoelectric effect according to claim 1 is characterized in that: The filter pressing and dehydration mechanism (3) comprises a central cavity disposed in the device body (1), the inlet of the central cavity being connected to the outlet of the mixing mechanism (2), and the outlet of the central cavity being connected to the sewage recovery tank (4), and two pressing plates (31) disposed side by side are disposed in the central cavity, one of the pressing plates (31) being fixed to the inner wall of the device body (1), and the other pressing plate (31) being driven and moved by a press (32) disposed in the device body (1), so as to squeeze and dehydrate the mixture in the central cavity.

3. The activated sludge dewatering device based on piezoelectric effect according to claim 2 is characterized in that: An annular permanent magnet and an electrode (34) are fixed to the sides of the two pressing plates (31) that are away from each other. An electromagnetic coil (33) is wound around the two permanent magnets. The electrode (34) is connected to an external power source via a wire. When the power source is turned on, the electromagnetic coil (33) generates an electromagnetic force, and the electrode (34) connects the pressing plate (31) and the power source to form a passage through the sludge water.

4. The activated sludge dewatering device based on piezoelectric effect according to claim 1 is characterized in that: The mixing mechanism (2) comprises a piezoelectric material dispenser (21) and a sludge stirring component (22); the output end of the piezoelectric material dispenser (21) is connected to the sludge stirring component (22); the piezoelectric material dispenser (21) dispenses the piezoelectric material into the sludge stirring component (22), and the sludge stirring component (22) stirs and mixes the piezoelectric material and the sludge; a sludge dispensing port (23) is provided at the bottom of the sludge stirring component (22), and the sludge dispensing port (23) is connected to the filter press dewatering mechanism (3); the mixed piezoelectric material and sludge mixture enters the filter press dewatering mechanism (3) through the sludge dispensing port (23).

5. The activated sludge dewatering device based on piezoelectric effect according to claim 4 is characterized in that: The piezoelectric material dispenser (21) is provided with a weight sensor for detecting the amount of piezoelectric material put into the sludge stirring component (22).

6. The activated sludge dewatering device based on piezoelectric effect according to claim 4, characterized in that: A solenoid valve is provided in the sludge delivery port (23).

7. The method for using the activated sludge dewatering device based on piezoelectric effect according to any one of claims 1 to 6, characterized in that: The steps include: Step 1: transporting the piezoelectric material and sludge in the piezoelectric material dispenser (21) to the mixing mechanism (2) for thorough mixing; Step 2: After the mixing is completed, the mixture is transported from the mixing mechanism (2) to the filter pressing and dehydration mechanism (3) for filter pressing, while a piezoelectric effect is generated, and dehydration is performed in conjunction with the generated electromagnetic force; Step 3: The removed water enters the sewage recovery tank (4) for recovery.

8. The method for using the activated sludge dewatering device based on piezoelectric effect according to claim 7, characterized in that: When the piezoelectric material is added in step 1, the amount of the piezoelectric material added is detected by a weight sensor.

9. The method for using the activated sludge dewatering device based on piezoelectric effect according to claim 7, characterized in that: After the piezoelectric material and sludge mixture are transported to the filter press dewatering mechanism (3) in step 2, the solenoid valve in the sludge delivery port (23) is closed.

10. The method for using the activated sludge dewatering device based on piezoelectric effect according to claim 7, characterized in that: The piezoelectric material in step 1 is MoS2.

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