Tail end filtering system of small domestic sewage treatment equipment

Abstract

The utility model relates to the technical field of domestic sewage treatment equipment, and provides a tail end filtering system of small domestic sewage treatment equipment, which comprises a skid-mounted box, the settling pond body is arranged at one corner in the skid-mounted box and is used for collecting the sewage subjected to biochemical treatment and settling the sewage to obtain supernatant containing suspended matters; the filtering tank body is arranged at the other corner, obliquely opposite to the sedimentation tank body, in the skid-mounted box and is used for filtering suspended matters in the supernate to obtain clear water; the clean water tank body is arranged in the skid-mounted box on the partition wall of the sedimentation tank body, is arranged side by side with the filter tank body and is used for collecting clean water. The sedimentation tank body, the filter tank body and the clean water tank body are reasonably arranged in the skid-mounted box, so that the structure is compact, and the occupied area is small; and the domestic sewage subjected to biochemical treatment is pre-precipitated by the precipitation tank body, so that the sewage treatment capacity of the filter tank body can be reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of domestic sewage treatment equipment, in particular to a terminal filtering system of small domestic sewage treatment equipment. Background Art

[0002] Domestic sewage refers to wastewater generated by daily human activities, including kitchen, bathroom, and toilet wastewater, which contains large amounts of organic matter and a considerable number of pathogenic microorganisms. This type of sewage requires treatment before it can be discharged into natural water bodies. In remote and sparsely populated areas, such as those experiencing scattered human habitation or field construction, small-scale domestic sewage treatment equipment is typically used to treat domestic sewage. Once treated, the water meets quality standards before discharge.

[0003] During treatment, domestic sewage is first pumped into a small domestic sewage treatment device. The front end of the device performs biochemical treatment on the domestic sewage, ensuring that indicators such as COD, BOD, TN, and TP meet discharge standards. At the same time, the biochemically treated domestic sewage also produces a large amount of suspended solids. Therefore, a dosing device and inclined tube sedimentation tank are generally installed at the end of the device, or MBR membrane technology or quartz sand filters are used as the terminal filtration system to complete the solid-liquid separation of suspended solids in the domestic sewage after biochemical treatment, so that the suspended solids in the final discharged domestic sewage meet discharge standards.

[0004] The above-mentioned terminal filtration system has the following characteristics:

[0005] 1. The combined use of a dosing device and an inclined tube sedimentation tank to remove suspended solids in domestic sewage requires the addition of a dosing device, which has high production costs, occupies a large area, and requires someone to add flocculants at any time, which is labor-intensive. The sludge precipitated after dosing is not suitable as the return sludge required by the domestic sewage treatment process, and has potential negative effects on the activated sludge system.

[0006] 2. The MBR membrane technology is used to remove suspended solids in domestic sewage, which is very effective. However, the investment cost is high, the energy consumption is large, the membrane is easily contaminated, and regular cleaning is required, which has high requirements for operation and management.

[0007] 3. Using quartz sand filters to remove suspended solids in domestic sewage can meet sewage discharge standards, but quartz sand filters have disadvantages such as bulky structure, uneven filter media, easy clogging of the filter layer, difficulty in backwashing, and difficulty in replacing filter media. Utility Model Content

[0008] In response to the shortcomings of the existing technology, the utility model provides a terminal filtration system for small domestic sewage treatment equipment, which has the advantages of compact structure, small footprint, good filtration effect, high degree of backwashing automation, long service life of filter material and easy replacement after failure.

[0009] To achieve the above objectives, the present invention provides the following technical solutions:

[0010] A terminal filtration system for a small domestic sewage treatment equipment, comprising:

[0011] skid mounted boxes;

[0012] The sedimentation tank is located in a corner of the skid-mounted box and is used to collect the biochemically treated sewage and precipitate the sewage to obtain a supernatant containing suspended matter;

[0013] A filter tank body is provided in another corner of the skid-mounted box diagonally opposite to the sedimentation tank body, and is used to filter suspended matter in the supernatant to obtain clean water; and

[0014] The clean water tank body is arranged in a skid-mounted box next to the sedimentation tank body and is arranged side by side with the filter tank body for collecting clean water.

[0015] In one embodiment disclosed in the present application, an overflow weir with an L-shaped cross-section is provided on the periphery of the sedimentation tank body for collecting the supernatant containing suspended matter after sedimentation;

[0016] The overflow weir is connected to the filter tank body through the upper hole and the L-shaped water inlet pipe to guide the supernatant from different parts of the overflow weir into the water inlet area of ​​the filter tank body;

[0017] The filter tank body below the water inlet area is provided with a filter area and a water and air distribution assembly in sequence. The filter area is used to intercept suspended matter to filter the supernatant to obtain clean water. The filter tank body below the water and air distribution assembly is an air-water chamber, which is used to discharge clean water to the clean water tank body and introduce backwashing medium to backwash the filter area.

[0018] The clean water tank body is communicated with the air-water chamber through a water supply and drainage pipeline.

[0019] In one embodiment disclosed in the present application, the filtration area includes a filter material layer and a support layer arranged above and below, and the filter material layer is quartz sand with a particle size of 0.9 mm to 1.2 mm and uniform gradation;

[0020] The water and gas distribution assembly includes a porous filter plate and a long-handled filter head installed in each through hole of the porous filter plate;

[0021] The porous filter plate is fixedly connected to the inner wall of the filter tank body on all sides to support the supporting layer;

[0022] The long-handled filter head is divided into a filter cap and a filter rod at the upper and lower parts;

[0023] The filter cap is placed on the porous filter plate, and its height is less than the thickness of the supporting layer;

[0024] The filter rod passes downward through the porous filter plate and then extends into the air-water chamber.

[0025] In one embodiment disclosed in the present application, the filter cap is a hemispherical bowl-shaped structure, and a plurality of long and thin slits are evenly opened on the curved surface thereof;

[0026] The filter rod is a hollow tube with a small hole on the upper part and strip holes on the lower part.

[0027] In one embodiment disclosed in the present application, an annular washing trough is provided on the inner side wall of the water inlet area. The washing trough is located below the upper hole and its lower edge is 120 mm higher than the top surface of the filter material layer.

[0028] The washing tank is connected to a drain pipe with an electric ball valve, and the drain pipe is connected to the outer side wall of the water inlet area and is located in the skid-mounted box.

[0029] In one embodiment disclosed in the present application, the air-water chamber is connected to an air supply pipeline;

[0030] The air supply pipeline is connected to the outer wall of the air-water chamber to provide compressed gas for backwashing.

[0031] In one embodiment disclosed in the present application, the gas supply pipeline includes a main gas pipe with a solenoid valve and a gas pressure throttling pipe connected in parallel to the gas outlet end thereof;

[0032] The air inlet end of the main air pipe is connected to the external air source, and the air outlet end is connected to the upper part of the air-water chamber;

[0033] A first solenoid valve and a first manual ball valve are sequentially installed on the air pressure throttling tube along the air flow direction. The first solenoid valve is used to control the on and off of the air pressure throttling tube, and the first manual ball valve is used to adjust the air washing intensity.

[0034] In one embodiment disclosed in the present application, the water supply and drainage pipeline includes a drainage branch and a water supply branch;

[0035] The drainage branch is used to discharge the clean water in the air-water chamber into the clean water tank body;

[0036] The water supply branch is used to pump the clean water in the clean water tank into the air-water chamber to provide water for backwashing.

[0037] In one embodiment disclosed in the present application, the drainage branch includes a water supply and drainage pipe section, a three-way valve, a three-way joint, and a water inlet pipe section connected in sequence, wherein one end of the water supply and drainage pipe section away from the three-way valve is connected to the lower part of the air-water chamber, and one end of the water inlet pipe section away from the three-way joint is connected to the lower part of the clean water tank body;

[0038] The water supply branch includes a water outlet pipe section, a backwash pump and a special-shaped pipe section connected in sequence, wherein the end of the water outlet pipe section away from the backwash pump is connected to the three-way joint, and the end of the special-shaped pipe section away from the backwash pump is connected to the three-way valve;

[0039] The water supply branch also includes a water pressure throttling pipe with both ends connected to the water supply and drainage pipe section and the upper part of the clean water tank body respectively. A second solenoid valve and a second manual ball valve are installed on the water pressure throttling pipe in sequence along the water flow direction. The second solenoid valve is used to control the on and off of the water pressure throttling pipe, and the second manual ball valve is used to adjust the water washing intensity.

[0040] In one embodiment disclosed in the present application, a discharge manhole with a sealing cover is provided on the outer side wall of the filter area for installing the long-handled filter head and replacing failed filter media;

[0041] A hand hole with a sealing cover is provided on the outer wall of the air-water chamber. The hand hole is located directly below the unloading manhole and is used to clean the sludge deposited in the air-water chamber to achieve cleaning of the air-water chamber.

[0042] Compared with the prior art, the beneficial effects of the present invention are:

[0043] 1. The sedimentation tank, filtration tank and clean water tank are rationally arranged in the skid-mounted box, with a compact structure and small footprint. The sedimentation tank is used to pre-precipitate the domestic sewage after biochemical treatment, which can reduce the amount of waste treated in the filtration tank.

[0044] 2. Through the long-handled filter heads installed in the through holes of the porous filter plate, filtered water, backwash water and compressed gas can evenly pass through multiple locations of the filter media layer, thereby maximizing the filtering function of the filter media and restoring the filtering capacity of the filter media to the greatest extent after backwashing.

[0045] 3. Through the small holes and strip holes set on the long-handled filter rod, the compressed gas can form a stable air cushion layer on the upper part of the air-water chamber, thereby ensuring that the compressed gas for air washing enters the filter material layer through each filter cap with equal flushing intensity, thereby ensuring that the filter material obtains the same air washing effect everywhere.

[0046] 4. By setting up the washing trough and emptying pipe, the water level in the water inlet area can be flush with the bottom edge of the washing trough during backwashing of the filter material, ensuring that the water level from the top surface of the filter material layer to the bottom edge of the washing trough is 120mm, so that the water pressure head in the water inlet area is low during backwashing, thereby saving energy consumption; during backwashing, the dirt entering the water inlet area can overflow into the washing trough evenly from all sides and be discharged, with a high dirt removal rate.

[0047] 5. The filter area adopts the three-stage combined flushing method of air washing - air-water mixed washing - water washing to backwash the filter material. The backwashing effect is good, the flushing is uniform, the filter material has a strong ability to recover the filtration effect, and the backwash water pressure head is low, the water consumption is small, and it is not easy to cause the filter material to be lost.

[0048] 6. Through the unloading manhole, the operator can easily install the long-handled filter heads outside the filter tank body and unload the expired filter media and replace them after thoroughly cleaning the filter area, thereby eliminating the need to enter the narrow space of the filter tank body, effectively eliminating life-threatening safety hazards. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0050] Figure 1 It is a schematic diagram of the three-dimensional structure of the utility model;

[0051] Figure 2 It is a schematic diagram of the arrangement of each pool body in the utility model;

[0052] Figure 3 It is a schematic diagram of the longitudinal cross-sectional structure of the filter tank body;

[0053] Figure 4 This is a schematic diagram of the three-dimensional structure of the water and gas distribution assembly;

[0054] Figure 5 Schematic diagram of the top view of the porous filter plate;

[0055] Figure 6 It is a schematic diagram of the three-dimensional structure of the long-handled filter head.

[0056] Figure 7 Schematic diagram of the three-dimensional structure of the emptying pipeline;

[0057] Figure 8 Schematic diagram of the three-dimensional structure of the gas supply pipeline;

[0058] Figure 9 It is a schematic diagram of the three-dimensional structure of the water supply and drainage pipeline. DETAILED DESCRIPTION

[0059] Hereinafter, only certain exemplary embodiments are briefly described. As will be appreciated by those skilled in the art, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and description are to be regarded as illustrative in nature and not restrictive.

[0060] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0061] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of this utility model, "plurality" means two or more, unless otherwise specifically defined.

[0062] In this utility model, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; they can refer to direct connection or indirect connection through an intermediate medium; they can refer to internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0063] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0064] The disclosure below provides many different embodiments or examples for realizing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present invention.

[0065] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0066] See also Figures 1 to 9 As shown, the utility model provides a terminal filtration system for a small domestic sewage treatment equipment, comprising:

[0067] skid mounted boxes;

[0068] The sedimentation tank 100 is located in a corner of the skid-mounted box and is used to collect wastewater after biochemical treatment and to precipitate the wastewater to obtain a supernatant containing suspended solids;

[0069] The filter tank body 200 is located in the other corner of the skid-mounted box diagonally opposite to the sedimentation tank body 100 and is used to filter suspended solids in the supernatant to obtain clean water; and

[0070] The clean water tank body 300 is disposed in a skid-mounted box next to the sedimentation tank body 100 and arranged side by side with the filter tank body 200 for collecting clean water.

[0071] Specifically, an overflow weir trough 110 with an L-shaped cross-section is provided on the periphery of the sedimentation tank body 100, which is used to collect the supernatant containing suspended matter after sedimentation; the overflow weir trough 110 is connected to the filter tank body 200 through the upper hole 111 and the L-shaped water inlet pipe 120, so as to introduce the supernatant from different parts of the overflow weir trough 110 into the water inlet area 210 in the filter tank body 200; the filter tank body 200 below the water inlet area 210 is provided with a filter area 220 and a water distribution and air distribution assembly 230 in sequence, the filter area 220 is used to intercept suspended matter to filter the supernatant to obtain clean water, and the filter tank body 200 below the water distribution and air distribution assembly 230 is an air-water chamber 240, which is used to discharge clean water to the clean water tank body 300 and introduce backwashing medium to backwash the filter area 220; the clean water tank body 300 is connected to the air-water chamber 240 through a water supply and drainage pipeline 400. The sedimentation tank body 1 is used to collect the sewage after biochemical treatment of various functional bodies at the front end of the small domestic sewage treatment equipment. After the sewage is precipitated in the sedimentation tank body 1, the supernatant containing some suspended matter enters the overflow weir trough 110. The supernatant from different parts of the overflow weir trough 110 flows through the upper hole 111 and the water inlet pipe 120 and is discharged into the water inlet area 210 in the filter tank body 200. The supernatant in the water inlet area 210 enters the filter area 220 for filtration. The suspended matter in the supernatant is intercepted and becomes clean water. The clean water flows through the water distribution and air distribution assembly 230 and enters the air-water chamber 240. The clean water is then discharged into the clean water tank body 300 through the water supply and drainage pipeline 400. The clean water in the clean water tank body 300 can be discharged into nature after subsequent disinfection, or it can be temporarily stored in the clean water tank body 300 as a water source for backwashing the filter area 220.

[0072] The filter area 220 includes a filter material layer 221 and a supporting layer 222 arranged above and below. The filter material layer 221 is quartz sand with a particle size of 0.9mm to 1.2mm and uniform gradation, and its filling thickness is 600mm. The supporting layer 222 is quartz sand with a particle size of 2 to 4mm and its filling thickness is 100mm. The quartz sand filter material has the advantages of fast filtration speed, small head loss, and small expansion rate during backwashing. The water and gas distribution assembly 230 includes a porous filter plate 231 and a long-handled filter head 232 installed in each through hole of the porous filter plate 231; the porous filter plate 231 is fixedly connected to the inner wall of the filter tank body 200 on all sides to support the supporting layer 222; the long-handled filter head 232 is divided into a filter cap 233 and a filter rod 234 at the upper and lower parts; the filter cap 233 is supported on the porous filter plate 231, and its height is less than the thickness of the supporting layer 222; the filter rod 234 passes downward through the porous filter plate 231 and extends into the air and water chamber 240. During filtration, the filter material layer 221 and the supporting layer 222 intercept the suspended matter in the supernatant from the water inlet area 210 to obtain clean water. The clean water enters the filter rod 234 from the filter cap 233 of each long-handled filter head 232, and then flows into the air-water chamber 240, realizing the filtration function of the filter area 220; during backwashing, backwashing media such as backwashing water and compressed gas enter the air-water chamber 240, then enter the filter rod 234 of the long-handled filter head 232, and enter the filter area 220 from the filter cap 233. The filter cap 233 evenly distributes the backwashing water and compressed gas with a certain flushing intensity into the filter area 220, realizing backwashing of the filter material in the filter area 220, and achieving good backwashing effect.

[0073] The filter cap 233 has a hemispherical bowl-shaped structure with multiple long, thin slits evenly distributed across its curved surface. This prevents leakage of filter media from the filter area 220 while ensuring uniform water and air distribution. The filter rod 234 is a hollow tube with small holes 234A at its top and strip holes 234B at its bottom. During filtration, clean water enters the filter rod 234 through the multiple long, thin slits in the cap 233 and is evenly discharged from the filter media. During backwashing, on the one hand, backwashing water enters the air-water chamber 240 from bottom to top, enters the filter rod 234 from the bottom, and gradually submerges the strip holes 234B and the small holes 234A; on the other hand, compressed gas enters the air-water chamber 240 from top to bottom and gradually gathers at the upper part of the air-water chamber 240 to form an air cushion layer, and the thickness of the air cushion layer continues to increase until it enters the filter rod 234 from the small holes 234A and the strip holes 234B at the position of the filter rod 234, and finally forms a stable air cushion layer; thereafter, backwashing water and compressed gas enter the filter area 220 from the multiple long and thin slits of the filter cap 233, realizing the uniform water and air distribution function of the filter material during backwashing.

[0074] In order to collect and discharge the contaminated backwash water entering the water inlet area 210 during backwashing, an annular washing water trough 211 is provided on the inner wall of the water inlet area 210. The washing water trough 211 is located below the upper hole 111 and its lower edge is 120 mm higher than the top surface of the filter material layer 221. The washing water trough 211 is connected to an emptying pipe 213 with an electric ball valve 212. The emptying pipe 213 is connected to the outer wall of the water inlet area 210 and is located in the skid-mounted box. When the filter area 220 is backwashed, the generated backwash water with dirt enters the water inlet area 210 and overflows evenly to the washing tank 211 in all directions, and the dirt collection effect is good; thereafter, the electric ball valve 212 controls the emptying pipe 213 to discharge the backwash water with dirt in the washing tank 211 to the outside of the system, ensuring that the water pressure head on the filter layer 221 is 120 mm, thereby reducing the head loss during backwashing, reducing the backwash water volume, and reducing energy consumption, and not easily causing filter material loss; at the same time, the annular washing tank 211 can discharge dirt evenly, with high efficiency.

[0075] The air-water chamber 240 is connected to an air supply line 250, which is connected to the outer wall of the air-water chamber 240 to provide compressed gas for backwashing. Specifically, the air supply line 250 includes a main air pipe 251 with a solenoid valve and a pressure throttling pipe 252 connected in parallel with its outlet. The air inlet of the main air pipe 251 is connected to an external air source (not shown in the figure), and the outlet is connected to the upper portion of the air-water chamber 240. A first solenoid valve 253 and a first manual ball valve 254 are installed on the pressure throttling pipe 252 in the direction of airflow. The first solenoid valve 253 is used to control the opening and closing of the pressure throttling pipe 252, and the first manual ball valve 254 is used to adjust the intensity of the air wash. The air supply line 250 provides compressed gas for backwashing of the filter media in the filter area 220, and can also automatically adjust the different flushing intensity requirements of the backwashing compressed gas during air washing and air-water mixed backwashing, so as to loosen the filter media and wash out the dirt in the filter media; moreover, the flushing intensity of the compressed gas during air-water mixed backwashing is lower than the flushing intensity of backwashing with compressed gas alone, so as to achieve the best flushing effect during the air-water mixed backwashing process, thereby effectively preventing the loss of filter media due to high flushing intensity during air-water mixed backwashing.

[0076] The water supply and drainage pipeline 400 includes a drainage branch 410 and a water supply branch 420. The drainage branch 410 is used to discharge the clean water in the air-water chamber 240 to the clean water tank body 300, and the water supply branch 420 is used to pump the clean water in the clean water tank body 300 into the air-water chamber 240 to provide water for backwashing. Specifically, the drainage branch 410 includes a water supply and drainage pipe section 411, a three-way valve 412, a three-way joint 413 and a water inlet pipe section 414 connected in sequence. The end of the water supply and drainage pipe section 411 away from the three-way valve 412 is connected to the lower part of the air-water chamber 240, and the end of the water inlet pipe section 414 away from the three-way joint 413 is connected to the lower part of the clean water tank body 300; the water supply branch 420 includes a water outlet pipe section 421, a backwash pump 422 and a special-shaped pipe section 423 connected in sequence. The water outlet pipe section 421 is away from the backwash pump 422 One end is connected to the three-way joint 413, and the end of the special-shaped pipe section 423 away from the backwash pump 422 is connected to the three-way valve 412; the water supply branch 420 also includes a water pressure throttling pipe 424 with two ends respectively connected to the water supply and drainage pipe section 411 and the upper part of the clean water tank body 300. A second solenoid valve 425 and a second manual ball valve 426 are installed on the water pressure throttling pipe 424 in sequence along the water flow direction. The second solenoid valve 425 is used to control the on and off of the water pressure throttling pipe 424, and the second manual ball valve 426 is used to adjust the water washing intensity. During filtration, the three-way valve 412 is in the straight-through pipeline working state, the air-water chamber 240 is connected to the clean water tank body 300 through the drainage branch 410, and the clean water entering the air-water chamber 240 after filtration is introduced into the clean water tank body 300; during backwashing, when the three-way valve 412 is in the vertical pipeline working state, the clean water tank body 300 is connected to the air-water chamber 240 through the water inlet pipe section 414, the three-way joint 413, the water supply branch 420, the three-way valve 412 and the water supply and drainage pipe section 411, and the backwash pump 422 is used to pump the clean water tank body 300. Clean water in the body 300 is pumped into the air-water chamber 240 to provide backwash water for backwashing the filter media in the filter area 220. At the same time, it can realize automatic adjustment of different backwashing intensity requirements of backwashing water during water washing and air-water mixed backwashing, so as to effectively wash out dirt in the filter media; moreover, the flushing intensity of water during air-water mixed backwashing is lower than the flushing intensity of backwashing with water alone, so as to achieve the best flushing effect during the air-water mixed backwashing process, thereby effectively preventing the loss of filter media due to high flushing intensity during air-water mixed backwashing.

[0077] Filtration and backwashing share a drainage branch 410. By changing the flow position of the three-way valve 412 flow channel, the clean water in the air-water chamber 240 is discharged to the clean water tank body 300 or the backwash water is pumped from the clean water tank body 300 into the air-water chamber 240 to backwash the filter material, reducing the backwash water source configuration, making the entire piping system compact in structure, occupying little space, and greatly reducing the manufacturing and operating costs.

[0078] As can be seen, the filter area 220 can backwash filter media clogged with sludge using a three-stage combined wash method: air wash, air-water mixed wash, and water wash. Before backwashing, the electric ball valve 212 controls the drain line 213 to be in a draining state. Water in the water inlet area 210 of the filter tank body 200 enters the wash tank 211 from all sides and is then discharged from the drain line 213. Ultimately, the remaining water in the filter tank body 200 is flush with the bottom edge of the wash tank 211, and the water surface is 120 mm from the top surface of the filter media layer 221. This ensures low hydrostatic pressure during backwashing and reduces backwashing energy consumption.

[0079] During air washing, the compressed gas provided by the external air source enters the upper part of the air-water chamber 240 through the main air pipe 251 and forms an air cushion layer at the lower part of the porous filter plate 231. As the compressed gas is continuously injected, the thickness of the air cushion layer continues to thicken. When the water level in the air-water chamber 240 continues to drop to the position of the small hole 234A and the strip hole 234B of the filter rod 234, the compressed gas enters the inside of the filter rod 234 through the small hole 234A and the strip hole 234B and enters the filter area 220 from the filter cap 233. The bubbles formed when the air passes through the filter material layer 221 produce shear and friction effects on the filter material during the rise, causing the dirt attached to the filter material to fall off, thereby realizing the air washing function of the filter material.

[0080] After the air wash is complete, mixed air and water washing is performed. The first solenoid valve 253 controls the air pressure throttle tube 252 to be open, allowing a portion of the compressed air in the main air pipe 251 to enter the air pressure throttle tube 252 and be discharged to the atmosphere through the first manual ball valve 254, thereby adjusting the air supply intensity of the main air pipe 251. The opening degree of the first manual ball valve 254 is preset to ensure that the compressed air intensity entering the air-water chamber 240 through the main air pipe 251 meets the requirements for mixed air and water washing. At the same time, the three-way valve 412 is in the vertical pipeline working state, connecting the clean water tank body 300 with the air-water chamber 240. The second solenoid valve 425 controls the water pressure throttle tube 424 to be open, diverting a portion of the clean water in the water supply and drainage pipe section 411 back to the clean water tank body 300. The opening degree of the second manual ball valve 426 is preset to ensure that after the water pressure throttle tube 424 adjusts the diversion, the backwash pump 422 pumps clean water from the clean water tank body 300 into the air-water chamber 240 with a flushing intensity that meets the requirements for mixed air and water washing. During the air-water mixed washing stage, compressed air and backwash water enter the filter media layer 221 simultaneously. The compressed air causes the filter media to slightly expand, and the filter media is in a fluidized state. The backwash water effectively removes the dirt that has fallen off the filter media during the air washing stage.

[0081] After the air-water mixed washing is completed, the solenoid valve on the main air pipe 251 and the second solenoid valve 425 of the water pressure throttling pipe 424 are closed, and the backwash pump 422 draws the clean water in the clean water tank body 300 into the air-water chamber 240 to backwash the filter material layer 221. At this time, the filter material is in a slightly expanded state, and the backwash water further brings the dirt in the filter material out of the filter material and rinses the filter material, so that the filter material is purified more thoroughly.

[0082] The dirt carried out during the three-stage combined washing process of air washing, air-water mixed washing and water washing enters the water inlet area 210 and flows into the washing tank 211 from the water surface to the surrounding areas along with the washing water, and is then discharged from the emptying pipe 213.

[0083] It can be seen that the bubbles formed by the compressed gas rising in the filter material during air washing have a disturbing effect, so that they collide and rub with the filter material, peel off the sludge attached to the surface of the filter material, and bring out some of the dirt in the filter material; after air washing, the compressed gas of the air-water mixture washing makes the surface of the filter material scrub, which makes it easier to remove the dirt on the surface of the filter material, and the backwash water makes the filter material suspended, which is conducive to gas cleaning, making it easier to fall off the dirt particles adhering to the filter material, with good backwashing effect, small backwashing water volume and low energy consumption; after the air-water mixture washing, backwashing with water is used to bring out the bubbles and suspended dirt remaining in the filter material, restore the filtering capacity of the filter material, effectively extend the service life of the filter material and prevent filter material loss.

[0084] A discharge manhole 223 with a sealed cover is located on the outer wall of the filter area 220. This is used to install long-handled filter heads 232 and replace expired filter media (i.e., filter media layer 221 and support layer 222). Through this manhole 223, operators can conveniently install each long-handled filter head 232 and remove expired filter media from outside the filter tank 200. This manhole 223 allows operators to replace the filter media after thoroughly cleaning the filter area, eliminating the need to enter the confined space of the filter tank 200 and effectively eliminating potential life-threatening safety hazards.

[0085] A hand hole 241 with a sealing cover is provided on the outer side wall of the air-water chamber 240 . The hand hole 241 is located directly below the unloading manhole 223 and is used to clean the sludge deposited in the air-water chamber 240 to achieve cleaning of the air-water chamber 240 .

[0086] To sum up, the sedimentation tank body 100, the filter tank body 200 and the clean water tank body 300 provided in the utility model are rationally arranged in the skid-mounted box, with a compact structure and a small footprint; the sedimentation tank body 100 is used to pre-precipitate the domestic sewage after biochemical treatment, which can reduce the sewage treatment capacity of the filter tank body 200; the filter area 220 adopts uniformly graded filter media, which has the advantages of long service life, high filtration efficiency, good filtration effect, good effluent water quality, small head loss, and small filter media expansion rate during backwashing, so as to filter out suspended matter in the supernatant to make its content meet the emission standards; in addition, the filter area 220 adopts a three-stage combined flushing method of air washing-air-water mixed washing-water washing to backwash the filter media blocked by sludge, and automatically controls the air and water inlet pressures at each stage to ensure the best backwashing effect, prevent the pressure from being too low to affect the backwashing effect, and prevent the filter media from being lost due to excessive flushing intensity.

[0087] The above embodiments are only preferred embodiments of the present invention and are not limitations on the technical solutions of the present invention. Any technical solution that can be implemented on the basis of the above embodiments without creative work should be deemed to fall within the scope of protection of the patent of the present invention.

Claims

1. A small domestic sewage treatment equipment terminal filtration system, characterized in that: include: skid mounted boxes; The sedimentation tank is located in a corner of the skid-mounted box and is used to collect the biochemically treated sewage and precipitate the sewage to obtain a supernatant containing suspended matter; The filter tank body is located in the other corner of the skid-mounted box diagonally opposite to the sedimentation tank body, and is used to filter suspended matter in the supernatant to obtain clean water; and The clean water tank body is arranged in a skid-mounted box next to the sedimentation tank body and is arranged side by side with the filter tank body for collecting clean water.

2. The terminal filtration system of the small domestic sewage treatment equipment according to claim 1 is characterized in that: The sedimentation tank body is provided with an overflow weir trough with an L-shaped cross section on the periphery thereof for collecting the supernatant containing suspended matter after sedimentation; The overflow weir is connected to the filter tank body through the upper hole and the L-shaped water inlet pipe to guide the supernatant from different parts of the overflow weir into the water inlet area of ​​the filter tank body; The filter tank body below the water inlet area is provided with a filter area and a water and air distribution assembly in sequence. The filter area is used to intercept suspended matter to filter the supernatant to obtain clean water. The filter tank body below the water and air distribution assembly is an air-water chamber, which is used to discharge clean water to the clean water tank body and introduce backwashing medium to backwash the filter area. The clean water tank body is communicated with the air-water chamber through a water supply and drainage pipeline.

3. The terminal filtration system of the small domestic sewage treatment equipment according to claim 2 is characterized in that: The filter area includes a filter material layer and a support layer arranged above and below, and the filter material layer is quartz sand with a particle size of 0.9mm to 1.2mm and uniform gradation; The water and gas distribution assembly includes a porous filter plate and a long-handled filter head installed in each through hole of the porous filter plate; The porous filter plate is fixedly connected to the inner wall of the filter tank body on all sides to support the supporting layer; The long-handled filter head is divided into a filter cap and a filter rod at the upper and lower parts; The filter cap is placed on the porous filter plate, and its height is less than the thickness of the supporting layer; The filter rod passes downward through the porous filter plate and then extends into the air-water chamber.

4. The terminal filtration system of the small domestic sewage treatment equipment according to claim 3 is characterized in that: The filter cap is a hemispherical bowl-shaped structure, and a plurality of long and thin slits are evenly opened on its curved surface; The filter rod is a hollow tube with a small hole on the upper part and strip holes on the lower part.

5. The terminal filtration system of a small domestic sewage treatment equipment according to claim 3 or 4, characterized in that: An annular washing trough is provided on the inner side wall of the water inlet area, and the washing trough is located below the upper hole and its lower edge is 120 mm higher than the top surface of the filter material layer; The washing tank is connected to a drain pipe with an electric ball valve, and the drain pipe is connected to the outer side wall of the water inlet area and is located in the skid-mounted box.

6. The terminal filtration system of a small domestic sewage treatment equipment according to any one of claims 2 to 4, characterized in that: The air-water chamber is connected to an air supply pipeline; The air supply pipeline is connected to the outer wall of the air-water chamber to provide compressed gas for backwashing.

7. The terminal filtration system of the small domestic sewage treatment equipment according to claim 6 is characterized in that: The air supply pipeline includes a main air pipe with a solenoid valve and an air pressure throttling pipe connected in parallel with the air outlet end thereof; The air inlet end of the main air pipe is connected to the external air source, and the air outlet end is connected to the upper part of the air-water chamber; A first solenoid valve and a first manual ball valve are sequentially installed on the air pressure throttling tube along the air flow direction. The first solenoid valve is used to control the on and off of the air pressure throttling tube, and the first manual ball valve is used to adjust the air washing intensity.

8. The terminal filtration system of a small domestic sewage treatment equipment according to claim 2 or 7, characterized in that: The water supply and drainage pipeline includes a drainage branch and a water supply branch; The drainage branch is used to discharge the clean water in the air-water chamber into the clean water tank body; The water supply branch is used to pump the clean water in the clean water tank into the air-water chamber to provide water for backwashing.

9. The terminal filtration system of a small domestic sewage treatment equipment according to claim 8, characterized in that: The drainage branch includes a water supply and drainage pipe section, a three-way valve, a three-way joint and a water inlet pipe section connected in sequence, wherein one end of the water supply and drainage pipe section away from the three-way valve is connected to the lower part of the air-water chamber, and one end of the water inlet pipe section away from the three-way joint is connected to the lower part of the clean water tank body; The water supply branch includes a water outlet pipe section, a backwash pump and a special-shaped pipe section connected in sequence, wherein the end of the water outlet pipe section away from the backwash pump is connected to the three-way joint, and the end of the special-shaped pipe section away from the backwash pump is connected to the three-way valve; The water supply branch also includes a water pressure throttling pipe with both ends connected to the water supply and drainage pipe section and the upper part of the clean water tank body respectively. A second solenoid valve and a second manual ball valve are installed on the water pressure throttling pipe in sequence along the water flow direction. The second solenoid valve is used to control the on and off of the water pressure throttling pipe, and the second manual ball valve is used to adjust the water washing intensity.

10. The terminal filtration system of the small-scale domestic sewage treatment equipment according to claim 3 is characterized by: The outer wall of the filter area is provided with a discharge manhole with a sealing cover plate for installing the long-handled filter head and replacing the failed filter material; A hand hole with a sealing cover is provided on the outer wall of the air-water chamber. The hand hole is located directly below the unloading manhole and is used to clean the sludge deposited in the air-water chamber to achieve cleaning of the air-water chamber.

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