Submerged membrane module based on ceramic membranes

Abstract

The claimed device for microfiltration is intended for purifying water of mechanical impurities, removing coagulant compounds, bacteria and viruses, performing a preparatory purification step prior to reverse osmosis, and increasing the concentration of activated sludge at purification plants, thus allowing a reduction in capital costs in the construction of water purification plants. The field of application of the claimed device includes water purification, water conditioning, purification plants, membrane microfiltration, and membrane bioreactors. The filtration area of the present module can be adjusted as required and is not fixed. The use of a ceramic membrane as a filter element renders the module resistant to chemical reagents and UV light and increases the service life thereof. The module is compact since all of the filtrate discharge pipes and pipes for enabling cross-filtration are integrated with a supporting frame.

Description

[0001] IMMERSION MEMBRANE MODULE ON CERAMIC MEMBRANES

[0002] The field of technology to which the utility model relates

[0003] The utility model relates to devices intended for water preparation and purification, can be used for purification of tap water at water intakes from open water sources, water accumulation and storage tanks as a filter for clarification, turbidity reduction, as a sludge separator or settling tank, as well as in treatment facilities operating using the MBR Membrane Bio Reactor technology. The utility model relates to ultrafiltration and microfiltration units using a set of ceramic membranes with a porosity of 0.01 to 100 μm as a filter.

[0004] State of the art

[0005] Currently, for water treatment or the stage of additional purification during water treatment, bulk sand filters - water clarifiers (FOV) are most often used in Russia, almost everywhere. In wastewater treatment technology, the membrane biological reactor (MBR) technology is gaining more and more popularity. This technology allows to reduce the dimensions of treatment facilities, reduce their cost, allows not to carry out additional purification of wastewater and at the same time guarantees to obtain purified wastewater. The following types of membranes are used at modern treatment facilities operating using the technology of membrane biological reactors (MBR or MBR - Membrane bioreactor):

[0006] 1. hollow fiber membranes;

[0007] 2. flat membranes with a polymer filtration layer;

[0008] 3. ceramic membranes.

[0009] In Russia, 90% of MBRs use hollow fiber membranes with a service life of no more than 3-5 years. It is too early to talk about the advantages of our development. It is better to move this information to the "Disclosure of the invention" section.

[0010] A device for filtering rainwater is known from the prior art (KR101906533B1, 10.10.2018), which is a membrane module (20) with porous ceramic plates used as a filter (21), with perforated tubes as aerators (53) to create cross-filtration, and an external permeate collection pipeline (31). The module frame is held by fastening plates (23). The authors use ceramic membrane plates, compressed air is used to create cross-filtration, but the height of the module is equal to the height of one filter ceramic plate. The module does not have the ability to attach other similar modules in height, the transport pipelines are not supporting units of the frame, but are located outside the module.

[0011] A device for filtering wastewater using ceramic membranes combined in a single housing is known, which is a flush-type membrane filter, its housing consists of covers connected to each other, forming a box (1), inside which ceramic membranes (15) are installed, permeate is removed through connecting tubes (7) (CN217895204U, 11 / 25 / 2022). The device is a filter with ceramic membrane plates inserted into it and fenced side and end covers. Ceramic plates are cleaned by flushing, there is no aeration of the plates. However, this model does not provide for the possibility of connecting other similar units, there is no air supply to create cross-filtration, and permeate is collected in pipelines outside the filter housing.

[0012] A membrane filter is known, where ceramic plates assembled into a single block are used as a filter element, and these blocks can be connected to each other in height (CN217264973U, 23.08.2022). The filter block consists of ceramic plates (1) and enclosure covers (2), the blocks are connected to each other using connecting pads (3). However, this module does not have a supporting frame in which air supply and permeate outlet pipelines can be located. Ceramic membranes are laid in a "checkerboard pattern", and permeate is removed from each membrane through two tubes located outside the module.

[0013] The closest in technical essence to the claimed device is a filtering product (100) using flat ceramic plates (101) connected in one holder (102), inside which there is a frame (103) for collecting permeate (RU2525421C2, 10.09.2012). However, this device does not provide for cross-filtration by supplying air between the ceramic plates, in addition, all the plates are glued into the frame to create a tight seal between the frame and the plate. This does not allow replacing one filtering unit - the ceramic plate; in case of plate breakage, it is necessary to replace the entire ceramic block.

[0014] The technical problem solved by the claimed utility model is the development of a water purification device with the ability to change the filtration area without changing the area of ​​the device occupied in terms of its location in a membrane biological reactor. The operation of the device and its maintenance, including chemical washing, must be fully automated.

[0015] Disclosure of a utility model

[0016] The technical result of the proposed utility model is:

[0017] 1. Extended service life of the submersible membrane module due to the use of inert filter material (ceramics), resistant to chemical reagents, UV radiation, drying, heating, with the possibility of backwashing under high pressure. Stainless steel is used as the material for the frame, aerators and side panels (covers).

[0018] 2. The filtration rating may vary depending on the pore size of the ceramic plate installed, and may be in the range of ultrafiltration and microfiltration.

[0019] 3. The membrane module is made from identical standardized blocks of the same size, using automatic welding machines of conveyor production, which reduces the cost of its production.

[0020] 4. The simplicity of connecting flange or bayonet connections of membrane blocks allows increasing the filtration area to the required dimensions, changing or adding membrane blocks. Thus, the membrane filter is made according to the principle of "open architecture", when one block is connected to another block. The increase in blocks occurs in height, does not change the dimensions of the membrane filter in the plane.

[0021] 5. The design of the membrane module allows achieving high filtration density per unit area of ​​the membrane biological reactor.

[0022] 6. The design allows for the most uniform distribution of transmembrane pressure on the filter elements. And if it is necessary to use large filtration areas, use membrane modules with different permeate pumping channels.

[0023] 7. Cross-filtration is provided by aeration from the lower aeration block of the membrane filter.

[0024] 8. The arrangement of all supply and discharge channels inside the frame of the membrane module makes it compact. The frame dimensions are calculated so as to ensure uniform distribution of transmembrane pressure and the same consumption of reagents during module flushing.

[0025] 9. The use of automatic shut-off valves and the ability to automatically turn on / off associated equipment makes the module fully automatic, operating according to a specified algorithm using automatic flushing, including chemical flushing.

[0026] The claimed technical result is achieved by a submersible membrane module on ceramic membranes with a variable filtration area, including one aeration block and at least one membrane block.

[0027] The product blocks are made of stainless materials, DIN 11850, DIN 2395; SMS, CAL, ISO standards. The aeration block frame is based on pipelines that simultaneously act as supply and discharge channels. For example, an air supply channel, a blow-off channel and plugged channels. They are connected by a frame through which air flows, supplied through the air supply channel to the aerators made of a perforated pipe. All channels end with connecting flanges to which the membrane block is attached. The lower part of the channels can have anchor plates that serve to attach the entire module to the concrete bottom of the tank, or the membrane block can be installed without fastening to the tank, can be lowered along the guides.

[0028] The membrane block consists of channels that serve as vertical supports for the frame and at the same time are channels for various purposes, such as an air supply channel, a purge channel, and permeate extraction channels. All channels are connected by pipes that provide rigidity to the structure and serve as supports for the ceramic plates, as well as a place to attach the ceramic plate plug to the permeate extraction tip. All channels end with connecting flanges. The sides of the membrane block are framed with covers to create cross-filtration, maintaining the air bubble movement strictly vertically between the ceramic plates.

[0029] The described utility model uses ceramic membranes with a service life of at least 15 years, but the membrane module itself is fundamentally different from the existing ones in that the membrane filtration area can be increased if necessary by installing additional filter blocks, while maintaining the area of ​​the module in plan. This is a sign of "open architecture". The rigidity of the structure is due to the choice of material - a stainless pipe and the shape of the block - a quadrangle. All air supply systems, permeate (filtrate) removal, aerator blowdown are located in the supporting frame of the module, there are no protruding pipelines that can be damaged during installation. In each filter block, you can easily replace a unit of the filter element - a membrane plate.

[0030] Brief description of the drawings

[0031] The utility model is explained by drawings, where Fig. 1 shows a diagram of a membrane module consisting of an aeration block and one membrane block; Fig. 2 shows a ceramic filter plate with end plugs; Fig. 3 shows a submersible membrane module in assembly, consisting of one aeration block and six membrane blocks; Fig. 4 shows a diagram of the piping of the membrane block with associated equipment and shut-off valves.

[0032] Designations on the drawings:

[0033] 1- aeration block frame;

[0034] 2- membrane block frame;

[0035] 3- air supply channel from blowers;

[0036] 4- water discharge channel;

[0037] 5- channel muted;

[0038] 6- channel muted;

[0039] 7- pipe perforated for aeration;

[0040] 8- flange;

[0041] 9 - anchor plates for fixing the PMM; 10 - permeate selection channel;

[0042] 11- channel for permeate selection;

[0043] 12- ceramic membrane frame covers;

[0044] 13- ceramic membranes;

[0045] 14 - ceramic plate plug with permeate outlet;

[0046] 15 - ceramic plate dead-end plug;

[0047] 16- compressor;

[0048] 17 - pneumatic valve for supplying purified water to a clean water tank;

[0049] 18 - pneumatic valve for supplying purified water for washing the MBR;

[0050] 19 - pneumatic valve for supplying reagent for washing the MBR;

[0051] 20 - pump for feeding permeate into a clean water tank;

[0052] 21 - pump for supplying purified water for washing the MBR;

[0053] 22- pump for feeding reagent for washing the MBR;

[0054] 23 - purified water capacity;

[0055] 24 - reagent capacity.

[0056] Implementation of a utility model

[0057] Below is a detailed description of the claimed utility model, which is of an explanatory nature, demonstrating the possibility of achieving the claimed technical result, without limiting the essence of the utility model. This technical solution may be subject to various changes and modifications, understandable to a specialist based on reading this description. Such changes do not limit the scope of claims. For example, the filtration area of ​​one block, the number of ceramic filter plates, the number of blocks, the diameter of pores in the plate, the vacuum of the permeate pipeline may change, the permeate pipelines can be connected to one pump or each pipeline to its own individual pump, the diameter of the holes in the perforated pipes of the aerators may change, the perforated pipes can be replaced with other aerators, the operating technology of the membrane module may change.

[0058] The claimed design of a submersible membrane module on ceramic membranes with a variable filtration area includes an aeration block 1 and a membrane block 2, and is schematically shown in Fig. 1. The aeration block is made of standard AISI 304 pipelines. The base of the aeration block frame is made of pipelines that simultaneously act as supply and discharge channels. For example, an air supply channel 3, a blow-off channel 4 and plugged channels 5 and 6 - they are connected by a frame along which air flows, supplied through the air supply channel - and aerators 7 made of a perforated pipe. All channels end with connecting flanges 8, to which the membrane block 2 will be attached. The lower part of the channels has anchor plates 9, which serve to fasten the entire module to the concrete bottom of the tank. Membrane block 2 (Fig.1) consists of channels that serve as vertical supports for the frame and at the same time are channels for various purposes, for example, air supply channel 3, water discharge channel 4 and permeate selection channels 10 and 11. Channels 10 and 11 perform the same function of transporting permeate from ceramic membranes to a vacuum pump. Channel 11 is connected if there are more than 10 filter blocks in the submersible membrane module. All channels are connected by pipes that ensure the rigidity of the structure and serve as supports for ceramic plates 13, as well as a place for attaching the plug of the ceramic plates to the permeate outlet tip 14 (Fig. 2). The sides of the membrane block are framed with covers 12 to create cross-filtration, maintaining the movement of the air bubble strictly vertically between the ceramic plates 13.

[0059] The proposed filter works as follows.

[0060] The aeration block 1 is attached to the bottom or wall of the tank, then the required number of membrane blocks are installed on it, calculating the required filtration area based on the specified filter capacity. The set of filtration blocks (2) to the required number serves as an element of "open architecture". The connection of the membrane block 2 to the aeration block is carried out using flanges 8.

[0061] Before starting work, the tank (membrane biological reactor) is filled with the liquid to be filtered, a recycle pump ensures a closed loop of liquid flow (not shown in the diagram, since it does not explain the operation of the utility model). Air is supplied to the submersible membrane module (Fig. 3) (channel 3), position 16 of Fig. 4, the channel for discharging the water-air mixture (channel 4) is opened, thereby releasing the aerators from water. As soon as only air comes out of the channel for discharging the water-air mixture, channel 4 is closed, all the air is directed along the membranes 13, and filtration can begin.

[0062] For filtration, pump pos. 20 in Fig. 4 is switched on, automatic valve pos. 17 is opened, with valves pos. 18 and 19 closed. A vacuum is created in channel 10 and, if necessary, channel 11 (Fig. 3). The pump motor frequency controller sets the vacuum in pipelines 10 or 11, and the filtration cycle is started. After a certain programmed time, the vacuum is removed from the permeate pipeline, valve 17 is closed, and backwash permeate is fed into the permeate channel under pressure P = 1 Bar by pump pos. 21 (Fig. 4) with valve pos. 21 open for 30 seconds and in a volume exceeding the obtained permeate by 2 times. This is enough to clean the filter channels in the plate and move away from the membrane the active sludge that has settled on it, which gets into the water-air flow going between the membranes, and is removed from the submersible membrane module by the airlift.

[0063] Chemical washing of the membrane module is carried out in the same way, only then sodium hypochlorite and / or citric acid are added to the flow of washing permeate from the reagent tank pos. 24, with valve 19 fig. 4 open, using the pump pos. 21 fig. 4. The washing time is 5 minutes, then the feed is stopped and the membrane module remains under pressure for 30 minutes. Then the permeate vacuum pump pos. 20 fig. 4 is turned on and within 10 minutes the permeate is drained into the equalizer, after which it is pumped into the purified wastewater tank. The process is automatic, the construction of liquid flow routes is carried out using automatic valves pos. 17; 18; 19 fig. 4.

[0064] The module is stable due to the shape of the membrane block 2, close to a square, the durability of the module is determined by ceramic filter elements, the material of the blocks is stainless steel. The possibility of attaching an additional number of blocks is ensured by the principle of open architecture, the use of the supporting structure as pipelines eliminates the module from protruding parts, the absence of a rigid fastening of the membrane plate to the frame makes it possible to replace the membrane plates.

[0065] To create the device, standard ceramic membranes 1000 mm long and 250 mm wide or plates of other sizes can be used, the device has the ability to replace a unit of the filter element - a ceramic plate, the device has compact dimensions (the dimensions of the membrane block are 1560 by 1040 mm with 80 pcs. membranes = 40 m 2filtration area). In addition, the claimed device does not contain protruding parts and provides cross-filtration along the filter element, has the ability to backwash and chemically wash without changing the design of the device and does not require its dismantling, as well as complete or partial disassembly.

[0066] Thus, the claimed model allows to increase the service life of filters for both water treatment and water purification, to make filter modules more compact, to change the filtration area with a constant area of ​​the module itself in plan.

Claims

FORMULA OF A UTILITY MODEL 1. A submersible membrane module for treating water or wastewater, comprising an aeration unit and at least one membrane block, the frame of the aeration block being based on pipelines with connecting flanges at the ends to which the membrane block is attached; the membrane block consists of channels serving as vertical supports for the frame, all channels being connected by pipes with connecting flanges at the ends, the sides of the membrane block being framed with covers.

2. A module characterized in that the blocks are made of materials complying with DIN 11850, DIN 2395; SMS, CAL, ISO standards.

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