A kind of upper drainage submerged membrane device and flushing control method thereof

Abstract

The present invention discloses an upper drainage submerged membrane device and a flushing control method thereof, comprising a sealed space provided inside the device body, an exhaust hole provided on the top; at least one membrane box fixed in the device body, a membrane assembly provided in the membrane box; a water inlet unit provided below the membrane box; a water production unit provided above the membrane box; an aeration unit provided below the membrane box; a backwash unit; an upper discharge unit provided above the membrane box; and a lower discharge unit provided below the membrane box. The lower water inlet and upper drainage of the present invention can realize intermittent air-water flushing during water production operation, and realize non-stop water flushing and upper drainage, so as to reduce the concentration of suspended matter during operation and reduce the flushing frequency; it can realize simplified flushing and drainage of only upper drainage but not lower drainage or lower drainage but not emptying for several times in the water production stage, and then perform a complete air-water flushing, air-water backwashing upper drainage, lower drainage, and emptying shutdown flushing and drainage, and the flushing and drainage in the water production stage can shorten the time consumed for drainage and intake, and reduce the drainage volume.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment membrane filtration, and in particular to an upper drainage submerged membrane device and a flushing control method thereof. Background Art

[0002] The submerged ultrafiltration membrane has the advantages of a large number of fillings and a large water output per pool, and is currently a widely used technology. The submerged ultrafiltration membrane is fixed by a membrane box, which is set in the membrane device. During water treatment, the membrane box is immersed and filtered through the ultrafiltration membrane. The flushing methods of submerged ultrafiltration membranes in the prior art include aeration cleaning and water backwashing. The principle of aeration cleaning is to pass compressed air from bottom to top, so that the membrane fibers swing and rub against each other, and the pollutants attached to the membrane fiber wall are peeled off; the principle of water backwashing is to flush the membrane fibers with backwash water, and the flushed sewage is discharged from the bottom sewage pipe.

[0003] The flushing method of the prior art has the following problems:

[0004] 1. The mud residue flushed out by aeration cleaning is suspended in the pool and cannot be discharged. It can only be taken out when the water is backwashed and drained. Therefore, the mud residue is easy to deposit at the bottom of the pool and accumulate at the roots of the membrane fibers. The amount of water discharged is large, and the time of drainage and re-intake is long.

[0005] 2. The flushing of the ultrafiltration membrane must be carried out in the shutdown state, which affects the overall processing efficiency;

[0006] 3. The top of the traditional ultrafiltration membrane device is not covered or the top cover does not bear pressure, and the transmembrane pressure difference is small, which affects the membrane flux.

[0007] Therefore, it is necessary to develop a new type of submerged membrane device. Summary of the invention

[0008] The object of the present invention is to provide an upper drainage submerged membrane device and a flushing control method thereof, so as to solve the technical problems in the prior art that the sludge flushed out by aeration cleaning is suspended in the pool and cannot be discharged outside, and can only be taken out when the water is backwashed and drained, so the sludge is easily deposited on the bottom of the pool and easily silted at the roots of the membrane fibers, and the amount of water discharged is large, and the drainage and re-intake time is long.

[0009] In order to achieve the above object, the first aspect of the present invention discloses an upper drainage submerged membrane device, comprising:

[0010] An upper drainage submerged membrane device, comprising:

[0011] A device body, wherein a sealed space is provided inside the device body and an exhaust hole is provided on the top;

[0012] At least one membrane box is evenly arranged and fixed in the device body, and a plurality of evenly arranged membrane modules are arranged in the membrane box;

[0013] A water inlet unit, arranged below the membrane box and used for supplying liquid into the device body;

[0014] A water production unit, arranged above the membrane box and used for collecting the filtrate of the membrane assembly;

[0015] An aeration unit, arranged below the membrane box, for aerating and flushing the membrane assembly;

[0016] A backwashing unit, used for introducing a backwashing liquid into the top of the membrane assembly for backwashing;

[0017] An upper discharge unit, arranged above the membrane box and used for discharging waste liquid;

[0018] The lower discharge unit is arranged below the membrane box and is used for lower discharge of waste liquid.

[0019] On the basis of the above technical solution, the present invention can also be improved as follows:

[0020] Furthermore, the water inlet unit includes a plurality of water inlet pipes extending laterally and evenly arranged below the membrane box, the water inlet pipes pass through the device body, and water inlet holes are evenly opened on the water inlet pipes; the lower discharge unit includes a plurality of mud discharge pipes extending laterally and evenly arranged below the water inlet pipes, the mud discharge pipes are evenly opened with mud discharge holes, and the mud discharge pipes and the water inlet pipes are arranged alternately in sequence.

[0021] By adopting the above solution, the water inlet holes are evenly distributed on the water inlet pipe, ensuring that water flows evenly into the bottom surface of the membrane assembly, so that the water flow rises evenly when air and water are flushed together.

[0022] Furthermore, the water inlet unit and the lower discharge unit are of integrated design, and the water inlet unit and the lower discharge unit include a plurality of water inlet and mud discharge pipes extending laterally and evenly arranged below the membrane box, and the water inlet and mud discharge pipes are evenly provided with perforations, and one end of the perforated water inlet and mud discharge pipe passes through the device body and is connected to the water inlet main pipe and the external discharge main pipe through the water inlet valve and the mud discharge valve respectively.

[0023] By adopting the above solution, the integrated design can assist in flushing the bottom of the device body and the mud discharge pipe when water enters, thereby avoiding mud accumulation in the pipeline and reducing mud accumulation on the bottom of the pool.

[0024] Furthermore, the water production unit includes a plurality of water production branches fixed on the top of the membrane box, the water production branches correspond to the membrane boxes one by one, and one end of the water production branches is connected to the top of the membrane assembly to collect filtrate, and the other end converges to a water production main pipe, and the water production main pipe is arranged inside the device body, passes through the device body, or is arranged outside the device body.

[0025] Furthermore, the backwash unit includes a backwash pump connected to the water production main pipe through a valve.

[0026] Furthermore, the upper row unit includes a plurality of upper drainage grooves arranged at even intervals, the upper drainage grooves are fixed above the membrane box, and one end of the upper drainage grooves is sealed and the other end is open, the device body and the corresponding position of the open end of the upper drainage groove are provided with an opening with the same cross-section as the upper drainage groove, a connecting piece is detachably installed on the inside of the opening, the upper drainage groove is connected to the opening via the connecting piece, and the device body is provided with an upper drainage pipe sealed and connected to the opening.

[0027] Furthermore, the top of the device body is opened, and a pressure cover is provided at the opening.

[0028] By adopting the above scheme, the water inlet volume can be increased until the water level reaches the top of the device body, and the water inlet volume can be continued to be increased to make the device body pressurized, increase the pressure difference on both sides of the membrane, thereby increasing the membrane flux and reducing the membrane usage, and adapting to the pressure difference changes caused by water volume, temperature, and the age of membrane fibers.

[0029] The second aspect of the present invention discloses a flushing control method for the above-mentioned upper drainage submerged membrane device, including intermittent flushing during the water production stage and flushing during the shutdown stage, wherein the intermittent flushing during the water production stage includes the following steps:

[0030] S11 closes the lower row unit and the upper row unit, opens the water inlet unit, and water enters from the bottom of the membrane box. When the water level exceeds the top of the membrane box, the water production unit is opened. Under the action of the pressure difference, water passes through the membrane layer and is collected and discharged by the water production unit. Pollutants in the water are intercepted by the membrane assembly. The water inlet volume is continuously increased until the water level reaches the top of the device body. After that, the water inlet volume is continuously increased. The device body is operated under pressure, the water level difference is increased, and the water production volume is increased.

[0031] S12 reduces the water inlet, keeps the water production unit open, and opens the upper row unit. The water level drops to the upper row unit. At this time, the water inlet is greater than the water outlet, forming a cross-flow filtration.

[0032] S13: continue to reduce the water inflow, close the water production unit, and open the aeration unit, so that air and water are flushed in the same direction under the action of the aeration unit and the water inlet unit, and the residual pollutants in the membrane assembly are discharged from the upper row unit, so as to realize the flushing of the membrane assembly;

[0033] S14: opening the water production unit, closing the upper discharge unit, increasing the water inflow until the water level is controlled above the membrane box to produce water at normal pressure, or increasing the water inflow until the water level is controlled above the top of the device body to produce water under pressure;

[0034] The shutdown stage flushing includes the following steps:

[0035] S21 single gas flushing: close the water inlet unit, water production unit, and lower discharge unit, open the upper discharge unit, lower the water level in the device body to the height of the top of the upper discharge unit, open the aeration unit, and allow compressed air to enter the lower part of the membrane assembly through the aeration unit. As the bubbles rise, the membrane fibers swing and rub against each other, and the pollutants attached to the membrane fiber walls are peeled off;

[0036] S22 Gas-water flushing: the water inlet unit is opened to allow water to flow in at a small flow rate, and the small flow rate of water and the gas flushing cooperate to carry pollutants upward and discharge them from the upper row unit;

[0037] S23 air-water backwashing: close the water inlet unit, open the backwashing unit, perform air-water backwashing, and keep discharging from the upper row unit;

[0038] S23 single water backwashing: open the lower row unit, close the aeration unit, close the upper row unit, and the pollutants entrained by the backwashing water are discharged from the lower row unit;

[0039] S24 venting: close the backwash unit, keep the lower discharge unit open until the water level in the device body is emptied, close the lower discharge unit, open the water inlet unit and the water production unit, and resume water production.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] 1. The upper discharge unit is arranged above the membrane box of the present invention, and the water inlet unit is arranged below, which can realize the simultaneous flushing of air and water and discharge pollutants upward, and the suspended matter between the membrane fibers and the washed matter on the membrane surface are floated up with the air flushing and discharged from the upper part driven by the water flow, so that the mud discharge is cleaner and the siltation at the root of the lower end of the membrane fibers and the siltation at the bottom of the pool can be reduced; the mud discharge measures are still retained at the bottom, and the easily settled particles can still be discharged downward;

[0042] 2. In the shutdown stage of the present invention, a single gas is first used to flush the membrane assembly, so that the membrane wires swing and rub against each other, and the pollutants attached to the membrane wire walls are peeled off, and then a small flow of water is introduced. The small flow of water can achieve the upper discharge of pollutants together with the compressed air, and is discharged through the upper discharge unit; then the backwash pump is turned on, and the compressed air and backwash water are used to further clean the membrane assembly. At this time, the upper discharge unit is still kept turned on, and the upper discharge is continued, and the mud residue from the backwashing remains under the membrane assembly; then the compressed air is turned off, and the lower discharge unit is turned on to flush the bottom pollutants out and discharge them through the lower discharge unit, and finally the backwash unit is turned off, and the water level is controlled to the operating water level by the lower discharge unit, and the lower discharge unit is turned off to resume water production, which effectively ensures the cleanliness of the membrane assembly and avoids the technical problems of the traditional flushing method that the mud discharge is not clean and thorough when only backwashing the lower discharge, the mud residue from the lower discharge is easy to accumulate at the root of the membrane wire, and the lower discharge is time-consuming and water-intensive;

[0043] 3. The present invention can realize water production operation and intermittent gas-water flushing at the same time, and realize non-stop water flushing and drainage, so as to reduce the concentration of suspended matter in operation and reduce the flushing frequency;

[0044] 4. The present invention can realize simplified flushing and drainage of only upper discharge but not lower discharge or lower discharge but not emptying for several times in the water production stage, and then perform a complete shutdown flushing and drainage of air-water forward flushing, air-water backwashing, upper discharge, lower discharge and emptying. The flushing and drainage in the water production stage can shorten the time consumed for drainage and reduce the drainage volume;

[0045] 5. A pressure cover is arranged on the top of the device body of the present invention. After the cover is installed and the device is operated under pressure, the system pressurization mode can be changed, water can be fed in before the membrane under pressure, or water can be directly produced by utilizing the surplus water head in front. The device body can also be superimposed with the existing technology, and a pressure control unit is still arranged after the membrane. The advantages of strong sewage interception capacity and large water production of a single pool are maintained, while the transmembrane pressure difference and membrane flux are increased, the membrane usage is reduced, and the device body size is reduced.

[0046] 6. The device of the present invention can be applied to an uncovered membrane device, the operating water level is higher than the membrane box but not higher than the top of the membrane device, and a pump can be installed in the water production main pipe to increase the water production. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0048] Figure 1 It is a schematic structural diagram of an upper drainage submerged membrane device according to an embodiment of the present invention.

[0049] Figure 2 yes Figure 1 Schematic diagram of the side structure.

[0050] As shown in the figure:

[0051] 1. Device body; 101. Exhaust hole; 102. Pressurization cover;

[0052] 2. membrane box; 201. membrane assembly;

[0053] 3. Water inlet and mud discharge pipe; 301. Water inlet valve; 302. Mud discharge valve;

[0054] 4. Water production branch;

[0055] 5. Upper drainage trough;

[0056] 6. Drainage trough through the wall pipe;

[0057] 7. Aerator;

[0058] 8. Connectors. DETAILED DESCRIPTION

[0059] The following embodiments of the technical solution of the present invention are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and cannot be used to limit the protection scope of the present invention.

[0060] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in this application should have the common meanings understood by those skilled in the art to which the present invention belongs.

[0061] like Figure 1 and Figure 2 As shown, the present embodiment provides an upper drainage submerged membrane device, comprising a device body 1, a sealed space is provided inside the device body 1, and an exhaust hole 101 is provided on the top.

[0062] Four membrane boxes 2 are evenly arranged and fixed in the device body 1, and membrane modules 201 are closely arranged in the membrane boxes 2.

[0063] A water inlet unit for supplying liquid to the inside of the device body 1 and a lower discharge unit for discharging waste liquid are provided below the membrane box 2. Specifically, the water inlet unit and the lower discharge unit are designed as an integrated whole in this embodiment, including five water inlet and mud discharge pipes 3 extending laterally and evenly arranged below the membrane box 2, and the water inlet and mud discharge pipes 3 are arranged at equal intervals between the mud collecting slope grooves. The water inlet and mud discharge pipes 3 are evenly perforated. The water inlet and mud discharge pipes 3 extend along the length direction of the device body 1 to cover its entire range, and one end of the water inlet and mud discharge pipe 3 passes through the device body 1 and is connected to the water inlet main pipe and the external discharge main pipe through the water inlet valve 301 and the mud discharge valve 302 respectively. The integrated design can assist in flushing the bottom of the device body 1 and the mud discharge pipe when taking in water, avoiding mud accumulation in the pipeline and reducing mud accumulation at the bottom of the pool.

[0064] In addition to the integrated setting, the water inlet unit and the downstream unit can also use independent water inlet pipes and mud discharge pipes to achieve normal water inlet and downstream operations.

[0065] A water production unit for collecting filtrate and an upper discharge unit for discharging waste liquid are provided above the membrane box 2. Specifically, the water production unit includes four water production manifolds 4 fixed on the top of the membrane box 2, the water production manifolds 4 correspond to the membrane box 2 one by one, and one end of the water production manifold 4 is connected to the top of the membrane assembly 201 to collect the filtrate, and the other end passes through the device body 1 and converges to the water production main pipe, and a flexible connection is provided at the wall where the water production manifold 4 passes through.

[0066] The upper row unit includes four upper drainage grooves 5 arranged evenly at intervals, and the four upper drainage grooves 5 are arranged one by one corresponding to the four membrane boxes 2. The upper drainage groove 5 is fixed above the membrane box 2, and one end of the upper drainage groove 5 is sealed and the other end is opened. The device body 1 is provided with an opening with the same cross section as the upper drainage groove 5 at the position corresponding to the open end of the upper drainage groove 5, and a connector 8 is detachably installed inside the opening, and the upper drainage groove 5 is connected to the opening through the connector 8. A drainage groove wall pipe 6 connected to the opening is provided outside the device body 1.

[0067] An aeration unit is also provided below the membrane box 2 , and the aeration unit is four aerators 7 corresponding to the four membrane boxes 22 one by one.

[0068] In order to achieve backwashing of the membrane assembly 201, this embodiment is further provided with a backwashing unit (not shown in the figure). The backwashing unit includes a backwashing pump connected to the water production main pipe through a valve.

[0069] The top of the device body 1 of this embodiment is opened, and a pressure cover 102 is provided at the opening, which can increase the water intake until the water level reaches the top of the device body 1, and continue to increase the water intake, so that the device body 1 is pressurized, increasing the pressure difference on both sides of the membrane, thereby increasing the membrane flux and reducing the membrane consumption, and adapting to the pressure difference changes caused by water volume, temperature, and the age of membrane fibers.

[0070] At the same time, this embodiment can also use a suction pump or the like to connect the water production unit to increase the required pressure difference, so as to achieve water production when the water level is higher than the membrane box 2 and the device body 1 is not filled.

[0071] The flushing control method of the submerged membrane device in this embodiment includes intermittent flushing during the water production phase and flushing during the shutdown phase. The intermittent flushing during the water production phase includes the following steps:

[0072] S11: Close the lower row unit and the upper row unit, open the water inlet unit, and water enters from the bottom of the membrane box 2. When the water level exceeds the top of the membrane box 2, open the water production unit. Under the action of the pressure difference, water passes through the membrane layer and is collected and discharged by the water production unit. The pollutants in the water are intercepted by the membrane assembly 201. Continue to increase the water inlet until the water level reaches the top of the device body 1. Then continue to increase the water inlet. The device body 1 runs under pressure, the water level difference increases, and the water production increases;

[0073] S12 reduces the water inlet, keeps the water production unit open, and opens the upper row unit. The water level drops to the upper row unit. At this time, the water inlet is greater than the water outlet, forming a cross-flow filtration.

[0074] S13 continues to reduce the water inflow, closes the water production unit, and opens the aeration unit. Under the action of the aeration unit and the water inlet unit, air and water are flushed in the same direction, and the residual pollutants in the entrained membrane assembly 201 are discharged from the upper row unit, so that the membrane assembly 201 is flushed and discharged;

[0075] S14 starts the water production unit, closes the upper discharge unit, increases the water inlet until the water level is controlled above the membrane box 2 for normal pressure water production, or increases the water inlet until the water level is controlled above the top of the device body 1 for pressurized water production.

[0076] The step S13 can be executed or not according to the inlet water quality. When the inlet water quality is good, the step S13 can be not executed or executed at intervals.

[0077] The flushing during the shutdown phase includes the following steps:

[0078] S21 single gas flushing: close the water inlet unit, water production unit, and lower discharge unit, open the upper discharge unit, lower the water level in the device body 1 to the height of the top of the upper discharge unit, open the aeration unit, and the compressed air enters the lower part of the membrane assembly 201 through the aeration unit. As the bubbles rise, the membrane fibers swing and rub against each other, and the pollutants attached to the membrane fiber walls are peeled off;

[0079] S22 Air-water flushing: Open the water inlet unit to let in water at a small flow rate. The small flow rate of water and air flushing will carry the pollutants upward and discharge them from the upper row unit;

[0080] S23 air-water backwash: close the water inlet unit, open the backwash unit, perform air-water backwashing, and keep discharging from the upper row unit;

[0081] S23 single water reverse flushing: open the lower row unit, close the aeration unit, close the upper row unit, and the pollutants entrained in the backwash water are discharged from the lower row unit;

[0082] S24 Draining: Close the backwash unit, keep the lower discharge unit open until the water level in the device body 1 is emptied, close the lower discharge unit, open the water inlet unit and the water production unit, and resume water production.

[0083] In the description of the present invention, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0084] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A flushing control method for an upper drainage submerged membrane device, characterized in that: The upper drainage submerged membrane device comprises: The device body has a sealed space inside and an exhaust hole on the top; At least one membrane box is evenly arranged and fixed in the device body, and a plurality of evenly arranged membrane modules are arranged in the membrane box; A water inlet unit, arranged below the membrane box and used for supplying liquid into the device body; A water production unit, arranged above the membrane box and used for collecting the filtrate of the membrane assembly; An aeration unit, arranged below the membrane box, for aerating and flushing the membrane assembly; A backwashing unit, used for introducing a backwashing liquid into the top of the membrane assembly for backwashing; An upper discharge unit, arranged above the membrane box and used for discharging waste liquid; A lower discharge unit is arranged below the membrane box and is used for lower discharge of waste liquid; The flushing control method includes intermittent flushing during the water production phase and flushing during the shutdown phase. The intermittent flushing during the water production phase includes the following steps: S11 closes the lower row unit and the upper row unit, opens the water inlet unit, and water enters from the bottom of the membrane box. When the water level exceeds the top of the membrane box, the water production unit is opened. Under the action of the pressure difference, water passes through the membrane layer and is collected and discharged by the water production unit. Pollutants in the water are intercepted by the membrane assembly. The water inlet volume is continuously increased until the water level reaches the top of the device body. After that, the water inlet volume is continuously increased. The device body is operated under pressure, the water level difference is increased, and the water production volume is increased. S12 reduces the water inlet, keeps the water production unit open, and opens the upper row unit. The water level drops to the upper row unit. At this time, the water inlet is greater than the water outlet, forming a cross-flow filtration. S13: continue to reduce the water inflow, close the water production unit, and open the aeration unit, so that air and water are flushed in the same direction under the action of the aeration unit and the water inlet unit, and the residual pollutants in the membrane assembly are discharged from the upper row unit, so as to realize the flushing of the membrane assembly; S14: opening the water production unit, closing the upper discharge unit, increasing the water inflow until the water level is controlled above the membrane box to produce water at normal pressure, or increasing the water inflow until the water level is controlled above the top of the device body to produce water under pressure; The shutdown stage flushing includes the following steps: S21 single gas flushing: close the water inlet unit, water production unit, and lower discharge unit, open the upper discharge unit, lower the water level in the device body to the height of the top of the upper discharge unit, open the aeration unit, and allow compressed air to enter the lower part of the membrane assembly through the aeration unit. As the bubbles rise, the membrane fibers swing and rub against each other, and the pollutants attached to the membrane fiber walls are peeled off; S22 Gas-water flushing: the water inlet unit is opened to allow water to flow in at a small flow rate, and the small flow rate of water and the gas flushing cooperate to carry pollutants upward and discharge them from the upper row unit; S23 air-water backwashing: close the water inlet unit, open the backwashing unit, perform air-water backwashing, and keep discharging from the upper row unit; S23 single water backwashing: open the lower row unit, close the aeration unit, close the upper row unit, and the pollutants entrained in the backwashing water are discharged from the lower row unit; S24 venting: close the backwash unit, keep the lower discharge unit open until the water level in the device body is emptied, close the lower discharge unit, open the water inlet unit and the water production unit, and resume water production.

2. The flushing control method according to claim 1, characterized in that: The water inlet unit includes a plurality of water inlet pipes extending laterally and evenly arranged below the membrane box, the water inlet pipes pass through the device body, and water inlet holes are evenly opened on the water inlet pipes; the lower discharge unit includes a plurality of mud discharge pipes extending laterally and evenly arranged below the water inlet pipes, the mud discharge pipes are evenly opened with mud discharge holes, and the mud discharge pipes and the water inlet pipes are arranged alternately in sequence.

3. The flushing control method according to claim 1, characterized in that: The water inlet unit and the lower discharge unit are of integrated design, and the water inlet unit and the lower discharge unit include a plurality of water inlet and mud discharge pipes extending laterally and evenly arranged below the membrane box, and the water inlet and mud discharge pipes are evenly provided with perforations, and one end of the perforated water inlet and mud discharge pipe passes through the device body and is connected to the water inlet main pipe and the external discharge main pipe through the water inlet valve and the mud discharge valve respectively.

4. The flushing control method according to claim 1, characterized in that: The water production unit includes a plurality of water production branches fixed on the top of the membrane box, the water production branches correspond to the membrane box one by one, and one end of the water production branch is connected to the top of the membrane assembly to collect filtrate, and the other end is converged to the water production main pipe, and the water production main pipe is arranged inside the device body, passes through the device body or is arranged outside the device body.

5. The flushing control method according to claim 4, characterized in that: The backwash unit comprises a backwash pump connected to the water production main pipe through a valve.

6. The flushing control method according to claim 1, characterized in that: The upper row unit includes a plurality of upper drainage grooves arranged at even intervals, wherein the upper drainage grooves are fixed above the membrane box, and one end of the upper drainage grooves is sealed and the other end is open. An opening with the same cross-section as the upper drainage groove is provided at a position corresponding to the open end of the upper drainage groove of the device body, and a connecting piece is detachably installed on the inner side of the opening, and the upper drainage groove is connected to the opening via the connecting piece, and an upper drainage pipe sealed and connected to the opening is provided outside the device body.

7. The flushing control method according to claim 1, characterized in that: The top of the device body is opened, and a pressure cover is provided at the opening.

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