A multi-disc type sand removing device and a method for treating sewage containing sand

Abstract

The application discloses a multi-stacking disc type sand removing device and a sand-containing sewage treatment method, and belongs to the technical field of environmental protection equipment. The device comprises a box body, multiple layers of stacking discs and a control system. A wear-resistant coating is coated at the sewage inlet of each layer of stacking discs. A branch pipe flow meter, an electric valve and a pressure gauge are separately arranged on the branch pipe connected with each layer of stacking discs. All the branch pipes are connected with a water inlet main pipe through a water distributor. The branch pipe flow meter, the electric valve and the pressure gauge are electrically connected with the control system. The control system is used for analyzing the detection data of the branch pipe flow meter and the pressure gauge, and controlling the opening degree of the electric valve on each stacking disc. The mechanical energy difference of each stacking disc is controlled to be within 5%. The device solves the problems of uneven water distribution and poor load impact resistance of the existing multi-layer cyclone grit chamber, guarantees the stability of the sand removing effect, and realizes the washing of the small gaps of the stacking discs through the self-provided backwashing and dredging function without introducing other washing equipment.

Description

Technical Field

[0001] This invention belongs to the field of environmental protection equipment technology, and more specifically, relates to a multi-disc sand removal device and a method for treating sand-containing wastewater. Background Technology

[0002] Currently, the mainstream grit removal processes both domestically and internationally primarily utilize horizontal flow grit chambers, aerated grit chambers, and mechanical vortex grit chambers. These grit chambers are typically designed to remove sand and gravel larger than 200μm. However, in actual operation, due to differences in geological topography across different regions, sand and gravel larger than 200μm only account for 20-40% of the influent, while sand and gravel larger than 106μm accounts for over 60%-80%. Traditional processes have limited efficiency in removing fine sand and silt. Influenced by design precision, existing technology, and the depth of process development, the efficiency of removing fine sand and silt is low, leading to sand and gravel accumulation in subsequent process stages and causing a series of operational problems. Therefore, multi-layer vortex grit chambers, due to their unique structure, can improve the sand removal precision and efficiency of existing grit chambers to a certain extent.

[0003] The working principle of a multi-layer vortex grit chamber is as follows: Utilizing shallow sedimentation combined with vortex sweeping, wastewater is tangentially introduced into the concrete tank through a channel. A water distributor evenly distributes the wastewater into each of the stacked plates, creating a vortex. Gravel settles to the surface of the stacked plates through gravity settling enhanced by the shallow sedimentation effect. Then, the vortex sweeping action captures the settled gravel from the plate surface and moves it to the bottom grit hopper, achieving a simultaneous improvement in grit removal efficiency and precision.

[0004] A search revealed Chinese patent application number 202321784148.X, filed on July 10, 2023, entitled "A High-Efficiency Aerated Grit Chamber." This application's high-efficiency aerated grit chamber includes an aerated sedimentation tank and a multi-layer vortex grit chamber. The output end of the aerated sedimentation tank is connected to the multi-layer vortex grit chamber. An aeration pipe is installed within the aerated grit chamber. The multi-layer vortex grit chamber is equipped with a multi-layer vortex solid-liquid separator. The multi-layer vortex solid-liquid separator includes separation discs spaced apart. Each separation disc includes an annular guide plate and a guide pipe. The guide pipe is spirally connected tangentially to the outer surface of the guide plate. A conical guide plate is provided at the bottom of the guide plate, and a solid discharge port is provided at the bottom of the conical guide plate. This application solves the problem of low grit removal accuracy in aerated grit chambers by adding a multi-layer vortex grit chamber at the end of the aerated grit chamber and utilizing the multi-layer vortex solid-liquid separator within the multi-layer vortex grit chamber to achieve fine grit removal. However, the multi-layer vortex grit chamber designed in this application has drawbacks in actual use, such as uneven water distribution between the discs, poor resistance to load impact, unstable treatment effect, and difficulty in sludge removal. It needs to be improved to meet the actual grit settling requirements and ensure that the grit settling process is stable. Summary of the Invention

[0005] 1. The problem to be solved

[0006] To address the problems of uneven water distribution and poor resistance to load impact in existing multi-layer vortex grit chambers, which lead to unstable treatment effects, a multi-disc grit removal device is proposed. By optimizing the structure of the existing multi-layer vortex grit chamber, the above problems are effectively solved, the grit removal efficiency and accuracy are improved, and the stability of the device's performance is ensured.

[0007] In addition, the present invention also provides a method for treating sand-containing wastewater using the above-mentioned sand removal device, which can still ensure stable operation of the sand settling process and stable sand removal effect even in scenarios with large fluctuations in water inflow, and is easy to clean and maintain.

[0008] 2. Technical Solution

[0009] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0010] Firstly, the present invention provides a multi-disc sand removal device, comprising a housing and multiple layers of discs disposed within the housing, and a control system, wherein:

[0011] Each layer of the stacked discs has a wear-resistant coating at its wastewater inlet. This coating effectively resists the impact of large particles in the wastewater on the disc surface, improving the device's resistance to load impacts and ensuring its service life. Additionally, each branch pipe connected to the stacked discs is equipped with a separate branch flow meter, electric valve, and pressure gauge. All branch pipes are connected to the main inlet pipe via a distributor.

[0012] The branch flow meter, electric valve, and pressure gauge are all electrically connected to the control system.

[0013] By analyzing the detection data from the branch pipe flow meters and pressure gauges through a control system and controlling the opening degree of the electric valves on each stacker, the mechanical energy difference of each stacker can be effectively ensured to be within ±5%, which helps to ensure the uniformity of water distribution and thus improves the sand removal effect. At the same time, to ensure uniform water distribution among the stackers, wide-threshold adjustment of the treated water volume can be achieved by adjusting the opening and closing of corresponding valves in application scenarios with large fluctuations.

[0014] In a preferred embodiment of the present invention, each branch pipe is individually connected to one end of a square tube via a pipe joint. A reinforced separation electric field assembly is detachably installed in the middle region of the square tube, and the other end of the square tube is extruded into a wedge-shaped tube structure, which is then attached to the outer wall of the stacked discs. The present invention facilitates the installation and removal of the reinforced separation electric field assembly by using square tubes, and the pipe joints allow for efficient connection between the circular branch pipes and the square tubes. The installed reinforced separation electric field assembly can utilize the various free radicals generated by the applied electric field during the sand removal process to pre-oxidize organic matter in wastewater, reducing the difficulty of subsequent treatment. If necessary, an oxidant can be added to the tank via a dosing pump. Under the action of the electric field, the oxidant and the electrocatalytic plate can couple to generate more free radicals and strong oxides, thus enhancing the pretreatment of the wastewater.

[0015] As a preferred embodiment of the present invention, the enhanced separation electric field assembly includes symmetrically arranged anode and cathode electrode plates and an external power supply. Slots are symmetrically machined on the horizontal wall of each square tube. Two electrode plates are arranged vertically through all square tubes and inserted into the slots of each square tube. The ends of the electrode plates are provided with terminals that are connected to the external power supply.

[0016] As a preferred embodiment of the present invention, the male and female electrode plates between two adjacent square tubes are connected by a tie rod. The tie rod is made of insulating material, which can keep the two electrode plates close to the square tube, thus ensuring the airtightness and reliable connection of the electrode plate installation to a certain extent.

[0017] As a preferred embodiment of the present invention, it also includes a backwash pipe, one end of which is connected to the housing and the other end is connected to the main water inlet pipe. A backwash pump and a backwash valve are installed on the backwash pipe. When the stacked discs become clogged, the system can be flushed and cleaned directly through the backwash pipe and the existing pipes, which can greatly save space and energy consumption, and thus complete the system self-cleaning.

[0018] As a preferred embodiment of the present invention, the main inlet pipe is equipped with a main pipe flow meter and a manual valve. The main pipe flow meter facilitates monitoring of the total inflow, and the manual valve facilitates individual control of the sand removal and backwashing processes.

[0019] As a preferred embodiment of the present invention, a sedimentation hopper is installed at the bottom of the lowest stacked tray, the sedimentation hopper is connected to the sand discharge pipe, and a water outlet pipe is also provided at the top of the box.

[0020] Secondly, a method for treating sand-containing wastewater according to the present invention uses the aforementioned sand removal device for sand removal, specifically including the following steps:

[0021] Step 1: Water enters through the main inlet pipe and is initially distributed to the branch pipes via the distributor;

[0022] Step 2: Each branch pipe is equipped with a separate branch pipe flow meter and pressure gauge to detect the incoming water, and the detection results are transmitted to the control system for processing.

[0023] Step 3: The control system calculates according to the built-in algorithm and ensures that the mechanical energy of the stacked discs is 0.05 to 0.15 MPa by adjusting the opening of the electric valve, and the difference in mechanical energy between any two stacked discs is within ±5%, thus completing the water distribution.

[0024] Step 4: Water intake and sand removal.

[0025] As a preferred embodiment of the present invention, in step one, the number of stacked trays to be put into operation is determined according to the inflow water volume, and the specific rules are as follows:

[0026] When the incoming water volume is more than 90% of the design water volume, all stacked trays will operate;

[0027] When the incoming water volume is 65% to 90% of the design water volume, no less than 80% of the stacked discs should be in operation;

[0028] When the incoming water volume is 35% to 65% of the design water volume, but does not include 65% of the design water volume, the stacked discs shall be operated at a rate of not less than 50% and not more than 80%.

[0029] When the incoming water volume is less than 35% of the design water volume, no more than 30% of the stacked trays shall be in operation.

[0030] As a preferred embodiment of the present invention, in step four, before sand removal from the influent, the enhanced separation electric field assembly installed on the branch pipe is activated. An external electric field is applied to draw charged sand particles closer to the stacked discs, thereby separating sand particles with the same charge from the wastewater and improving the sand removal effect. Furthermore, the free radicals and strong oxides generated by the applied electric field can also oxidize and degrade organic matter in the wastewater, reducing the difficulty of subsequent wastewater treatment.

[0031] As a preferred embodiment of the present invention, after sand removal is completed, when the stacked discs become clogged, backwashing is performed. The backwashing steps are as follows:

[0032] Once a blockage is identified in the stacked discs, close the electric valves on the branch pipes of the remaining unblocked stacked discs and the manual valves on the main inlet pipe;

[0033] Turn on the electric valve on the branch pipe of the clogged stacking disc and the backwash pump and backwash valve on the backwash pipe to flush the clogged stacking disc.

[0034] 3. Beneficial effects

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] The multi-disc sand removal device provided by this invention, through its optimized structural design, can solve the problems of uneven water distribution and poor load impact resistance of existing multi-layer vortex grit chambers. It not only ensures the stability of sand removal effect, but also has a built-in backwashing and sludge removal function, which can achieve the rinsing of the small gaps of the discs without the need for external flushing equipment.

[0037] Furthermore, the sand removal device of the present invention, by setting up an enhanced separation electric field component, can, on the one hand, pre-oxidize the organic matter in the sewage before sand removal, which helps to reduce the difficulty of subsequent sewage treatment; on the other hand, by controlling the polarity of the electric field, sand particles with a certain polar charge can be moved towards the side wall of the stacked disc, thereby achieving rapid separation of sand particles.

[0038] The sand-containing wastewater treatment method of this invention utilizes the sand removal device of this invention to automatically control the opening degree of the electric valves in each branch pipe, effectively ensuring the uniformity of water distribution and improving the separation effect. Simultaneously, by applying an external electric field during the sand removal process, the charged substances in the wastewater are controlled to move towards the sidewalls of the stacked discs, further enhancing the separation effect. Furthermore, the applied electric field can generate free radicals, oxidizing organic matter in the wastewater and reducing the difficulty of subsequent wastewater treatment. Even more optimized, if the device becomes clogged after prolonged operation, it can be flushed and cleaned through the backwash pipe. Attached Figure Description

[0039] Figure 1 This is a three-dimensional structural diagram of the multi-disc sand removal device of the present invention;

[0040] Figure 2 This is a three-dimensional structural schematic diagram of the multi-disc sand removal device from another perspective of the present invention.

[0041] Figure 3 This is a schematic diagram of the mounting structure of the electrode plate of the present invention;

[0042] In the picture;

[0043] 1. Housing; 101. Support frame; 102. Stacking trays; 103. Sedimentation hopper; 104. Water outlet valve; 105. Sand discharge valve; 106. Wear-resistant coating; 2. Electrode plate; 3. Terminal block; 4. Square tube; 5. Pipe joint; 6. Branch pipe; 601. Branch pipe flow meter; 602. Electric valve; 603. Pressure gauge; 7. Water distributor; 701. First vent valve; 8. Main inlet pipe; 801. Main pipe flow meter; 802. Manual valve; 9. Backwash pipe; 901. Backwash pump; 902. First backwash valve; 903. Second vent valve; 904. Second backwash valve. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed in the following specification.

[0045] It should be noted that in the description of this invention, the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0046] Furthermore, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "setting," "connection," "fixing," "screw connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0047] Furthermore, it should be understood that, for ease of description, the dimensions of the various components shown in the accompanying drawings are not drawn to actual scale; for example, the thickness or width of some layers may be exaggerated relative to other layers.

[0048] The present invention will be further described below with reference to specific embodiments.

[0049] Example 1

[0050] like Figure 1 and 2 As shown in the figure, this embodiment provides a multi-disc sand removal device, including a housing 1 and multiple layers of discs 102 disposed within the housing 1. In this embodiment, four layers of discs 102 are specifically provided. It also includes a control system. Each layer of discs 102 is connected to a branch pipe 6, which is individually equipped with a branch pipe flow meter 601, an electric valve 602, and a pressure gauge 603. All branch pipes 6 are connected to the main inlet pipe 8 through a water distributor 7. The water distributor 7 is equipped with a first vent valve 701, which can effectively prevent sand and soil from accumulating in the water distributor 7. The branch pipe flow meter 601, electric valve 602, and pressure gauge 603 are all electrically connected to the control system.

[0051] Specifically, in this embodiment, the desanding device uses a submersible pump as the water supply source. The incoming water flows through the main inlet pipe 8 to the distributor 7 for homogenization and mixing. The distributor 7 has multiple flange interfaces connected to the inlets of each stacked disc 102 via branch pipes 6. Each branch pipe 6 is equipped with a branch flow meter 601 and an electric valve 602. Because the inlet elevation and pipe length differ between the different stacked discs 102, the energy loss along the way also varies. To ensure the sand separation effect of each stacked disc 102, the mechanical energy at the inlet of each stacked disc 102 needs to be maintained within a fixed range. The control system in this embodiment analyzes the flow parameters of the branch flow meter 601 and the reading of the pressure gauge 603, and adjusts the electric valve 602 according to a built-in algorithm to maintain the mechanical energy at the inlet of each stacked disc 102 within the range of 0.05–0.15 MPa. Furthermore, the difference in mechanical energy between the stacked discs 102 needs to be controlled within 5%, ensuring that each stacked disc 102 has a high separation efficiency. Meanwhile, the device in this embodiment can also combine the incoming water volume and the fluctuation of the incoming water volume, and coordinate with the opening and closing of the electric valves 602 of different stacked discs 102 to put different numbers of stacked discs 102 into operation to ensure water distribution uniformity. In application scenarios with large fluctuations, the wide threshold adjustment of the treated water volume can also be achieved by adjusting the opening and closing of the corresponding valves.

[0052] It should be noted that the built-in algorithm mentioned in this embodiment is mainly based on Bernoulli's equation P + 1 / 2ρv 2 +ρgh=C, P is obtained from pressure gauge 603, v is obtained from flow meter 601, and gravitational potential energy is negligible. Calculate the mechanical energies C1, C2, C3… of each stacked disc 102. For those with larger mechanical energies, adjust electric valve 602 to increase water flow resistance and decrease inlet mechanical energy. For those with smaller mechanical energies, increase electric valve 602 to reduce water flow resistance and increase inlet mechanical energy.

[0053] All stacked disks 102 have mechanical energies C1, C2, C3, ... , which should satisfy dc = 9μB / (πv'ρN), where μ is the constant viscosity of water, B is the inlet width, v' is derived from the mechanical energy C, ρ is the density of water, and N can be calculated from the hydraulic residence time and v'.

[0054] Furthermore, since the wastewater entering the stacked discs 102 contains large sand particles with a certain initial velocity, they can easily cause impacts on the sidewalls of the stacked discs 102 at the water inlet, resulting in damage to the surface of the stacked discs 102 and affecting the sand settling effect. In this embodiment, a wear-resistant coating 106 is applied to the wastewater inlet of each stacked disc 102, which can effectively protect the local surface at the inlet of the stacked discs 102.

[0055] Example 2

[0056] Combination Figure 1 and Figure 3This embodiment of a multi-disc sand removal device has the same structure as Embodiment 1, but differs in that each branch pipe 6 is individually connected to one end of a square tube 4 via a pipe joint 5. One end of the pipe joint 5 is machined into a circular structure, and the other end into a square structure, thus connecting the branch pipe 6 and the square tube 4. The square tube 4 facilitates the disassembly and installation of the enhanced separation electric field assembly. To facilitate the connection between the square tube 5 and the stacked discs 102, the end of the square tube 4 furthest from the pipe joint 5 is gradually compressed to form a wedge-shaped tube structure, and its vertical tube wall, which is attached to the stacked discs 102, extends outward and protrudes from the tube opening, and is welded to the outer wall of the stacked discs 102.

[0057] Based on engineering experience, the applicant discovered that sand particles in the same wastewater often carry the same charge. Utilizing this characteristic, an additional electric field can be applied near the wastewater inlet of the stacked disc 102 to alter the trajectory of the sand particles entering the disc. By controlling the polarity of the electric field, the sand particles are controlled to approach the sidewall of the stacked disc 102 with an initial radial velocity, enabling rapid separation of wastewater and sand. However, this design has certain drawbacks. Wastewater often contains some larger particles, which possess significant kinetic energy under the influence of water flow. During separation at the wall, these particles often cause significant impact on the inner wall of the equipment, leading to localized erosion over time. While achieving good results in sand separation, this reduces the service life of the stacked disc 102. Therefore, this embodiment applies a highly wear-resistant coating to the sidewall of the stacked disc 102 at the wastewater inlet to enhance the impact resistance of this area and ensure stable operation of the equipment.

[0058] Furthermore, in some situations, when it is necessary to remove inorganic particles carrying specific charges from wastewater, the enhanced separation electric field component of the present invention can be activated to separate the inorganic particles with specific charges from the wastewater.

[0059] Furthermore, the enhanced separation electric field assembly described in this embodiment includes symmetrically arranged anode and cathode electrode plates 2 and an external power supply. Slots are symmetrically machined on the horizontal wall of each square tube 4, that is, with... Figure 1 Taking the orientation of the tube as an example, slots are provided on the upper and lower horizontal walls of each square tube 4. The electrode plate 2 is a single piece of electrode plate, made of anode and cathode plates with electrocatalytic oxidation function, such as titanium plates with coating. Charged inorganic particles in the wastewater are deflected towards the side wall of the stacked disk 102 by the electric field in the electric field area, improving the separation effect. Organic particles are initially oxidized by various free radicals generated by the electrode plate, reducing the difficulty of subsequent treatment. Further optimization, to enhance the electrocatalytic oxidation effect, an oxidant can be added to the water tank via a dosing pump. The oxidant couples with the electrocatalytic electrode plate to generate more free radicals and strong oxides, thus enhancing the pretreatment of the wastewater.

[0060] Two electrode plates 2 are vertically inserted through all the square tubes 4 and inserted into slots in each square tube 4. Each electrode plate 2 has a terminal block 3 at its end, which connects to an external power source. The male and female electrode plates 2 of adjacent square tubes 4 are connected by tie rods, allowing the two electrode plates 2 to be tightly pressed against the upper and lower horizontal walls of the square tubes 4. This ensures a certain degree of sealing during installation. Furthermore, since electrode plates 2 are prone to passivation over extended periods, the insertion and tie rod installation method facilitates quick disassembly and replacement of the electrode plates 2. It is worth noting that the tie rods in this embodiment are made of insulating material, such as PVC.

[0061] Example 3

[0062] Combination Figure 1 and Figure 2 This embodiment of a multi-disc sand removal device has the same structure as Embodiment 2, but differs in that it also includes a backwash pipe 9. One end of the backwash pipe 9 is connected to the housing 1, and the other end is connected to the main water inlet pipe 8. A backwash pump 901, a first backwash valve 902, a second backwash valve 904, and a second vent valve 903 are installed on the backwash pipe 9. Specifically, the second vent valve 903 is located between the housing 1 and the backwash pump 901. The second vent valve 903 serves two purposes: firstly, it allows for the venting of wastewater from the housing 1 during equipment maintenance, facilitating subsequent recycling; secondly, it allows for cleaning of the backwash pipe 9 if it becomes clogged after long-term use. The first backwash valve 902 is installed near the housing 1 to supply clean water to the housing 1, and the second backwash valve 904 is installed near the main water inlet pipe 8 to prevent water from entering the backwash pipe 9 during sand removal.

[0063] In addition, the main inlet pipe 8 is equipped with a main pipe flow meter 801 and a manual valve 802. During backwashing, the manual valve 802 can be closed, and the backwash pump 901 and backwash valve can be turned on to flush the stacked discs 102. The gaps between the stacked discs 102 are small and deep, making it difficult to clean them thoroughly with ordinary mechanical cleaning. This invention, by adding a backwash pipe 9, utilizes the device's own inlet pipe and increases the flow rate and hydraulic conditions to achieve a brief flushing effect on the stacked discs 102, effectively removing scale from the gaps in the stacked discs 102. No additional external cleaning equipment is required, enabling the device to self-clean. During cleaning, each stacked disc 102 is flushed sequentially from top to bottom. The cleaning time for each stacked disc 102 is controlled to be 10-30 minutes. The cleaning of the remaining stacked discs 102 is the same as above. The electric valve 602 on the corresponding branch pipe 6 is opened, and the valves of the remaining stacked discs 102 are closed, and the cleaning is carried out sequentially.

[0064] In this embodiment of the sand removal device, a sand settling hopper 103 is installed at the bottom of the lowest stacked disc 102. The sand settling hopper 103 is connected to a sand discharge pipe, and a sand discharge valve 105 is installed on the sand discharge pipe to control sand discharge. A water outlet pipe is also provided on the upper part of the housing 1, and a water outlet valve 104 is installed on the water outlet pipe to control water discharge.

[0065] Example 4

[0066] like Figure 1 and Figure 2 As shown, this embodiment provides a method for treating sand-containing wastewater, which uses the sand removal device described in Embodiment 3 for sand removal, and specifically includes the following steps:

[0067] Step 1: Water enters through the main inlet pipe 8 and is initially distributed to each branch pipe 6 through the distributor 7;

[0068] In step one, the number of stacked trays 102 to be put into operation is determined based on the incoming water volume, according to the following rules:

[0069] When the incoming water volume is more than 90% of the design water volume, all stacked trays 102 will operate;

[0070] When the incoming water volume is 65% to 90% of the design water volume, no less than 80% of the stacked discs 102 shall be in operation;

[0071] When the incoming water volume is 35% to 65% of the design water volume, but does not include 65% of the design water volume, the stacked disc 102 shall operate at a rate not less than 50% and not more than 80%;

[0072] When the incoming water volume is less than 35% of the design water volume, no more than 30% of the stacked discs 102 shall be in operation.

[0073] In this embodiment, the water inflow is specifically 95% of the designed water flow, and all four stacked trays 102 are in operation.

[0074] Step 2: Each branch pipe 6 is equipped with a separate branch pipe flow meter 601 and pressure gauge 603 to detect the incoming water, and the detection results are transmitted to the control system for processing.

[0075] Step 3: The control system calculates according to the built-in algorithm and adjusts the opening of the electric valve 602 and the power of the pump to ensure that the mechanical energy of the stacked discs 102 is between 0.05 and 0.15 MPa, and the difference in mechanical energy between any two stacked discs 102 is within ±5%, that is, the water distribution is completed; in this embodiment, the mechanical energies controlled by the four stacked discs 102 are 0.101 MPa, 0.102 MPa, 0.103 MPa, and 0.104 MPa, respectively.

[0076] It should be noted that the mechanical energy setting at the inlet of the stacked disc 102 can be adjusted according to the on-site water quality. For water containing fine particles, the mechanical energy of each stacked disc 102 needs to be increased to ensure the removal rate of fine sand. For wastewater containing larger particles, the mechanical energy setting needs to be reduced to reduce the scouring of the stacked disc 102.

[0077] Step 4: Water intake and sand removal.

[0078] Before the sand is removed from the influent, the enhanced separation electric field component installed on the branch pipe 6 is activated to select positively charged sand particles in the sewage and control the positively charged sand particles to move closer to the side wall of the stacked disc 102.

[0079] When the stacked disc 102 becomes clogged after the equipment has been in operation for a long time, backwashing is performed. The backwashing steps are as follows:

[0080] Once the blockage of the stacked disc 102 is identified, the electric valve 602 on the branch pipe 6 of the remaining unblocked stacked disc 102 and the manual valve 802 on the main inlet pipe 8 are closed.

[0081] Turn on the electric valve 602 on the branch pipe 6 of the clogged stacking disc 102 and the backwash pump 901 and backwash valve on the backwash pipe 9 to flush the clogged stacking disc 102.

[0082] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A multi-disc sand removal device, comprising a housing (1) and multi-layer stacked discs (102) disposed within the housing (1), characterized in that, It also includes a control system, in which: Each stacked disc (102) has a wear-resistant coating (106) at its sewage inlet, and each stacked disc (102) is equipped with a branch flow meter (601), an electric valve (602) and a pressure gauge (603) on its branch pipe (6). All branch pipes (6) are connected to the main inlet pipe (8) through a distributor (7). The branch flow meter (601), electric valve (602) and pressure gauge (603) are all electrically connected to the control system; The control system is used to analyze the detection data of the branch flow meter (601) and pressure gauge (603), and control the opening degree of the electric valve (602) on each stack plate (102) to keep the mechanical energy difference of each stack plate (102) within 5%. Each branch pipe (6) is individually connected to one end of the square pipe (4) via a pipe joint (5). The middle area of ​​the square pipe (4) is detachably equipped with a reinforced separation electric field assembly. The other end of the square pipe (4) is extruded to form a wedge-shaped tube structure, which is attached to the outer wall of the stack (102). The reinforced separation electric field assembly is used to apply an external electric field to the middle area of ​​the square pipe (4). It also includes a backwash pipe (9), one end of which is connected to the tank (1) and the other end is connected to the main water inlet pipe (8), and a backwash pump (901) and a backwash valve are installed on the backwash pipe (9); The main inlet pipe (8) is equipped with a main pipe flow meter (801) and a manual valve (802); the bottom of the lowest stacked plate (102) is equipped with a sedimentation hopper (103), which is connected to the sand discharge pipe, and the upper part of the box (1) is also equipped with a water outlet pipe.

2. The multi-disc sand removal device according to claim 1, characterized in that, The enhanced separation electric field assembly includes symmetrically arranged anode and cathode electrode plates (2) and an external power supply. Each square tube (4) has symmetrically machined slots on its horizontal tube wall. Two electrode plates (2) are arranged vertically through all square tubes (4) and inserted into the slots of each square tube (4). The electrode plates (2) are provided with terminals (3) at their ends, and the terminals (3) are connected to the external power supply.

3. The multi-disc sand removal device according to claim 2, characterized in that, The positive and negative electrode plates (2) between two adjacent square tubes (4) are connected by a tie rod, which is made of insulating material.

4. A method for treating sand-containing wastewater, characterized in that, The sand removal device as described in any one of claims 1-3 is used for sand removal, specifically including the following steps: Step 1: Water enters through the main inlet pipe (8) and is initially distributed to each branch pipe (6) through the distributor (7); Step 2: Each branch pipe (6) is equipped with a branch pipe flow meter (601) and a pressure gauge (603) to detect the incoming water. The detection results are transmitted to the control system for processing. Step 3: The control system calculates according to the built-in algorithm and ensures that the mechanical energy of the stacked discs (102) is 0.05~0.15MPa by adjusting the opening of the electric valve (602), and the difference in mechanical energy between any two stacked discs (102) is within ±5%, that is, the water distribution is completed. Step 4: Water intake and sand removal.

5. A method for treating sand-containing wastewater according to claim 4, characterized in that, In step one, the number of stacked trays (102) to be put into operation is determined according to the inflow water volume, and the specific rules are as follows: When the incoming water volume is more than 90% of the design water volume, all stacked trays (102) will operate; When the incoming water volume is 65% to 90% of the design water volume, no less than 80% of the stacked discs (102) shall be in operation; When the incoming water volume is 35% to 65% of the design water volume, but does not include 65% of the design water volume, the stacked discs (102) shall operate at a rate of not less than 50% and not more than 80%; When the incoming water volume is less than 35% of the design water volume, no more than 30% of the stacked discs (102) shall be in operation.

6. A method for treating sand-containing wastewater according to claim 4, characterized in that, In step four, before the sand is removed from the influent, the charged sand in the sewage is selected by activating the enhanced separation electric field component set on the branch pipe (6), and a certain polarity charge is controlled to move towards the side wall of the stacked plate (102).

7. A method for treating sand-containing wastewater according to any one of claims 4-6, characterized in that, After sand removal is completed, if the stacked disc (102) becomes clogged, backwashing is performed. The backwashing steps are as follows: Identify the clogged stacking disc (102), and close the electric valve (602) on the branch pipe (6) of the remaining unclogged stacking discs (102) and the manual valve (802) on the main inlet pipe (8). Turn on the electric valve (602) on the branch pipe (6) of the sludge stack (102) and the backwash pump (901) and backwash valve on the backwash pipe (9) to flush the sludge stack (102).

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