Novel backwash system for reducing fluid consumption during backwash of a multi-media filter

Abstract

This invention relates to a novel backwashing system (10) for a multi-media filter (20) to reduce fluid consumption and hydraulic resistance during the backwashing process. The system (10) includes a filter container (20) having a fluid inlet (30) and a fluid outlet (40). Particulate filter layers (50A)-(50C) are located between the fluid inlet (30) and the fluid outlet (40). A bottom distributor (60) is in fluid flow communication with a backwash fluid supply device (70). An auxiliary distributor (80A)-(80C), in fluid flow communication with the backwash fluid supply device (70), is arranged to be positioned within each particulate filter layer (50A)-(50C). The system (10) is characterized by backwashing each particulate filter layer (50A)-(50C) via the auxiliary distributor (80A)-(80C) and backwashing the entire filter container (20) in combination with the bottom distributor (60).

Description

Technical Field

[0001] This invention relates to a novel backwashing system for multi-media filters. More particularly, the invention relates to a system with horizontally arranged auxiliary distributors for a backwashing procedure. The system also relates to a method for controlling the backwashing procedure of a fluid handling system to minimize the fluid volume required for the backwashing procedure. Background Technology

[0002] Multimedia filtration refers to a water treatment process that uses multiple layers of different filter media to remove various contaminants or impurities from water. This type of filtration is commonly used in industrial, municipal, and commercial water treatment processes to produce water of specific qualities.

[0003] like Figure 1 As shown, the multi-media filter 1000 typically consists of a vertical column 1002, a container, or a tank containing several layers 1004a, 1004b, and 1004c of different materials. These materials are arranged based on their density and / or size, with the densest material 1004a at the bottom and the lightest (i.e., least dense) material 1004c at the top. Anthracite, sand, and garnet are typically used to form the different layers.

[0004] Water flows from the top inlet 1006 through the multi-media filter 1000 to the bottom outlet 1008. As it passes through each layer 1004a-1004c, contaminants or impurities of different sizes are captured by the corresponding media. Thus, the media in each layer acts as a filter. Larger particles or impurities are captured in the top layers 1004c and 1004b, while finer particles or impurities are captured and / or trapped as the water moves downwards in the multi-media filter.

[0005] Over time, the trapped contaminants or impurities cause the multi-media filter 1000 to become clogged. If clogged, the multi-media filter can no longer perform its filtration function optimally. To clean the clogged multi-media filter, a process called backwashing is employed. During backwashing, a large volume of water is forced under low pressure through sprayers 1010 and each layer 1004a to 1004c of the multi-media filter 1000, from the bottom (through sprayers 1010) to the top. In other words, during the backwashing procedure, the flow direction of fluid through the multi-media filter is reversed. By forcing a large volume of water through each layer 1004a to 1004c of the multi-media filter 1000, each layer 1004a to 1004c is fluidized, causing the accumulated contaminants or impurities trapped in the relevant layers to detach. The detached contaminants or impurities are transported upwards, through the continuous layers 1004a to 1004c of the multi-media filter 1000, and exit the multi-media filter 1000. In this way, the multi-media filter 1000 can be unblocked.

[0006] However, the backwashing process does bring its own set of challenges and drawbacks. Some of the main challenges and drawbacks are: - Fluid consumption: One of the main concerns about backwashing is the required fluid volume. Especially in areas where fluids are scarce, the amount of fluid used during backwashing can be wasteful and uneconomical.

[0007] - Energy consumption: Backwashing processes require one or more pumps to reverse the flow of fluid and increase its velocity in order to thoroughly clean the medium. This process consumes a significant amount of energy, especially in large fluid handling plants.

[0008] - Potential media loss: If backwashing is not performed correctly, it can lead to the loss of filter media, especially if the backwash rate is too high. This will corrode the media over time, making it necessary to replace the media more frequently.

[0009] While backwashing is an essential process for maintaining multi-media filters, the challenges and drawbacks mentioned above highlight the need for improved multi-media filter backwashing systems and methods.

[0010] Purpose of the invention

[0011] Therefore, one object of the present invention is to provide a novel backwashing system for multi-media filters and a method for controlling the backwashing procedure of multi-media filters, which avoids the above-mentioned disadvantages and / or provides a useful alternative to known backwashing systems, procedures and methods for controlling backwashing procedures for multi-media filter systems. Summary of the Invention

[0012] According to a first aspect of the present invention, a novel backwashing system for a multi-media filter is provided for reducing fluid consumption during the backwashing process of the multi-media filter, wherein the system comprises: - A filter container having a fluid inlet located at the top of the operating area for supplying fluid containing impurities into the filter container, and a fluid outlet located at the bottom of the operating area of ​​the filter container for discharging filtered fluid out of the filter container. - A granular filter layer is arranged inside the filter container and located between the fluid inlet and the fluid outlet, the granular filter layer being used to filter impurities from the fluid; - A bottom distributor, in fluid flow communication with the backwash fluid supply device, is arranged in the bottom region of the filter container during operation; and - Auxiliary distributors, arranged horizontally to be positioned within each granular filter layer, wherein the auxiliary distributors are in fluid flow communication with the backwash fluid supply device, and wherein they are used to introduce backwash fluid into each granular filter layer. The backwashing system is characterized in that, depending on the requirements of the granular filter layers, each granular filter layer is backwashed independently by a horizontal auxiliary distributor, and the entire filter container is backwashed in combination with a bottom distributor, thereby reducing the consumption of backwash fluid used during the backwashing process and reducing the hydraulic resistance within the filter container.

[0013] In another aspect of the invention, the backwashing process causes fluidization of the granular filter layer to release impurities trapped within the filter layer.

[0014] Impurities can be suspended particles in a fluid. Suspended particles can be silt, clay, gravel, organic matter, algae, and / or other microorganisms. However, those skilled in the art will understand that impurities can be any particles or molecules that must be filtered from the fluid. For example, impurities can also be fine minerals, salts, etc.

[0015] The filter container can be a pressurized multi-media filter container. A multi-media filter container may include a base for vertically supporting the filter container. That is, the multi-media filter container can be supported by a base such that the fluid outlet is located near the base, and the fluid inlet is located above the fluid outlet and the base. Therefore, the multi-media filter container can be in the form of a vertical well or column.

[0016] Those skilled in the art will understand that, in the backwashing process of a system, the fluid inlet of a container can be used as the fluid outlet of the backwash fluid. Similarly, in the backwashing process of a system, the fluid outlet of a multi-media filter container can be used as the fluid inlet of the backwash fluid. Alternatively, the backwashing system may also include a dedicated inlet for introducing backwash fluid into the multi-media filter container and a dedicated outlet for conveying the backwash fluid, along with impurities, out of the multi-media filter container.

[0017] The system's bottom distributor may include sprayers, annular rotating devices, ducts, a transverse system comprising transverse pipes or channels branching from a central manifold, pulsators, and / or nozzles. The bottom distributor is configured to uniformly distribute backwash fluid from the bottom region of the multimedia filter container upwards toward the top of the multimedia filter container.

[0018] Multiple granular filter layers can be disposed within a multi-media filter container and between its fluid inlet and outlet. For example, a first granular filter layer can be disposed at the bottom region of the multi-media filter container during operation, a second granular filter layer can be disposed on top of the first granular filter layer, and a third granular filter layer can be disposed on top of the second granular filter layer. Those skilled in the art will understand that more than three granular filter layers can be disposed in a multi-media filter container.

[0019] Each granular filter layer may include a specific granular filter medium. That is, the granular filter medium of the first granular filter may be different from the granular filter media of the second and third granular filter layers. Similarly, the granular filter medium of the second granular filter layer may be different from the granular filter media of the first and third granular filter layers. The granular filter medium of one granular filter layer may differ from that of another granular filter layer in terms of particle size and / or density. Examples of relevant filter media include anthracite, sand, garnet, gravel, activated carbon, rutile, magnetite, and crushed glass.

[0020] An auxiliary distributor can be configured to be located within each granular filter layer for fluidizing and backwashing each granular filter layer from the inside upward toward the fluid inlet of the multi-media filter container.

[0021] The backwash fluid inlet supplies backwash fluid to the bottom distributor and auxiliary distributor. Alternatively, the bottom distributor and auxiliary distributor can be connected to a separate backwash fluid supply unit. The backwash fluid supply unit can be connected to the fluid inlet.

[0022] The backwash fluid supply device may include a pump for supplying backwash fluid to the bottom distributor and various auxiliary distributors at a pressure higher than ambient pressure.

[0023] The auxiliary distributor may take the form of a sprayer, a ring-shaped rotary device, a pulsator, and / or a nozzle. Each auxiliary distributor is configured to distribute backwash fluid upwards from within the relevant granular filter layer toward the fluid inlet of the multi-media filter container.

[0024] In another aspect of the invention, the novel backwashing system may include various sensors for monitoring and / or control: - The flow rate of the feed fluid to be filtered into the multi-media filtration vessel; - The flow rate of the filtered fluid exiting the multi-media filter container; - The flow rate of backwash fluid through the bottom distributor and / or auxiliary distributor; - The flow rate of the fluid leaving the multi-media filter container; - Pressure within the multi-media filter container (typically below and above the relevant granular filter layer); and - Temperature of the backwash fluid and / or the feed fluid to be filtered and / or the granular filter bed.

[0025] Ideally, a bottom pressure sensor and a top pressure sensor are provided for each granular filter layer. For example, a first pressure sensor can be located near the bottom surface of the first granular filter layer during operation, and a second pressure sensor can be located near the top surface of the first granular filter layer during operation. The first and second pressure sensors can then be used to calculate the pressure difference across the first granular filter medium.

[0026] Sensors can be electronic sensors configured to communicate with the control system via a network. Examples of associated network communication include the Internet, wired electronic connections, or wireless electronic connections. In other words, various sensors can be configured to receive and transmit electronic communication signals to the control system.

[0027] The backwash system may include various valves for controlling the flow rate of fluids (i.e., the fluid to be filtered and the backwash fluid) to and from the multimedia filter container. Valves may be configured to control the flow of backwash fluid from the backwash fluid supply device to the bottom distributor and / or auxiliary distributor. Valves may include electronic sensors configured to network with the control system. That is, the valve may be configured to receive and send electronic communication signals to the control system. The valve may also be configured to be remotely operable from the control system. For example, the valve may include an electronic actuator for closing and opening the valve, which can be remotely and electronically closed and opened from the control system. Here, the electronic communication signals may be sent from the control room to the valve.

[0028] In another aspect of the invention, the control system may include a computing environment configured to receive input signals (i.e., electronic communication signals) from sensors, perform calculations based on the received input signals, and provide an output signal to the valve. The input and output signals may be transmitted between the sensors, the valve, and the computing environment via network communication. The output signal typically takes the form of an electronic communication signal sent to the valve and configured to cause its electronic actuator to open or close the valve.

[0029] The computing environment may include: - A communication module used to receive electronic communication signals from electronic sensors and valves and send those signals back to the sensors and valves; - A storage module for storing computer-readable instructions related to the operation of the backwashing system; and - A central processing unit used to retrieve computer-readable instructions from storage modules and process those instructions to provide output data. The output data is in the form of electronic communication signals to the sensor and valve.

[0030] Output data may include electronic communication signals to the valve's electronic actuator. For example, the electronic communication signals may cause the valve to open or close partially or completely to control the flow rate of fluid through the valve and into or out of the multi-media filter container.

[0031] The computing environment may also include input and output devices to allow users of the computing environment to interact with it and control the operation of the backwashing system and / or the backwashing procedure of the multi-media filter container.

[0032] Those skilled in the art will understand that the computing environment can be a physical computing environment or a virtual computing environment.

[0033] According to another aspect of the present invention, a method for controlling the backwashing procedure of a backwashing system is provided. The method includes the following steps: - The differential pressure across the granular filter layer is measured by comparing pressure readings from a pressure sensor located near the bottom surface of the granular filter layer with pressure readings from a pressure sensor located near the top surface of the granular filter layer; - Compare the measured differential pressure across the granular filter layer with a predetermined maximum differential pressure across the granular filter layer and a predetermined minimum differential pressure across the granular filter layer; - If the measured differential pressure across the granular filter layer is equal to or greater than the predetermined maximum differential pressure across the granular filter layer, then the backwashing procedure of the system is initiated; and If the measured differential pressure across the granular filter layer is equal to or less than a predetermined minimum differential pressure, then the backwashing procedure of the backwashing system is stopped.

[0034] The method may include additional steps of recording the time when the backwashing process of the backwashing system begins and recording the time when the backwashing process of the backwashing system ends.

[0035] Before initiating the backwashing procedure of a backwashing system including a multi-media filter, the method may include the step of closing a valve that controls the flow of the fluid to be filtered to the multi-media filter container.

[0036] The backwashing procedure of the backwashing system can be started by opening the valve that controls the flow of backwash fluid from the backwash fluid supply device to the bottom distributor and / or auxiliary distributor.

[0037] After the backwashing process of the backwashing system is started, the method of controlling the backwashing process of the backwashing system may also include the following additional steps: - The flow rate of backwash fluid exiting the bottom distributor and / or the auxiliary distributor is measured by a fluid flow sensor; - Compare the measured backwash fluid flow rate with a predefined minimum backwash fluid flow rate threshold and a predefined maximum backwash fluid flow rate threshold; - If the measured backwash fluid flow rate is equal to or greater than the predefined maximum backwash fluid flow rate threshold, then reduce the backwash fluid flow rate through the bottom distributor and / or the auxiliary distributor; and If the measured backwash fluid flow rate is equal to or less than the predetermined minimum backwash fluid flow rate, then increase the backwash fluid flow rate through the bottom distributor and / or the auxiliary distributor.

[0038] The flow rate of backwash fluid through the bottom distributor and / or auxiliary distributor can be reduced by closing the valve that controls the flow of backwash fluid from the backwash fluid supply unit to the bottom distributor and / or auxiliary distributor. For example, the valve can be partially closed until the measured backwash fluid flow rate is 20% lower than the preset maximum backwash fluid flow rate.

[0039] Similarly, the flow rate of backwash fluid through the bottom distributor and / or auxiliary distributor can be increased by opening a valve that controls the flow of backwash fluid from the backwash fluid supply device to the bottom distributor and / or auxiliary distributor. For example, the valve can be partially opened until the measured flow rate of backwash fluid is 20% higher than a predefined minimum backwash fluid flow rate.

[0040] The method for controlling the backwashing procedure of the backwashing system can be a computer-implemented method. That is, each step of the method can be executed and / or initiated in a computing environment. The computing environment can be a computing environment that forms part of the control system. Attached Figure Description

[0041] The invention will now be further described by way of non-limiting example only and with reference to the accompanying drawings, in which: Figure 1 This is a schematic side view of a known backwashing system (prior art); Figure 2 This is a schematic side view of a backwashing system according to one embodiment of the present invention; Figure 3 It is one of the embodiments of the present invention. Figure 2 A schematic side view of a second embodiment of the backwashing system; Figure 4 It is one of the embodiments of the present invention. Figure 2 A schematic diagram of the third embodiment of the backwashing system; Figure 5 It is one of the embodiments of the present invention and Figure 2 A schematic diagram of the computing environment for the network communication of the backwashing system; Figure 6This illustrates control according to one embodiment of the present invention. Figures 2 to 4 A flowchart illustrating the steps of the backwashing procedure in a backwashing system; and Figure 7 Control according to one embodiment of the present invention Figures 2 to 4 The second process flowchart of the backwashing procedure of the backwashing system. Detailed Implementation

[0042] The invention will be more readily understood by referring to the following detailed description of the invention, which is incorporated herein by reference and forms part of the accompanying drawings. It should be understood that the invention is not limited to the specific devices, methods, conditions, or parameters described and / or shown herein, and that the terminology used herein is for illustrative purposes only and is not intended to limit the claimed invention.

[0043] Furthermore, as used in the specification, including the appended claims, the singular forms “a,” “an,” and “the” include the plural, and references to a particular numerical value include at least that particular value unless the content clearly indicates otherwise. When another embodiment is expressed with such a range, the range may be expressed as from “about” or “approximately” to another particular value. Moreover, it will be understood that, unless otherwise stated, the dimensions and material properties stated herein are for illustrative purposes and not for limitation, and variations beyond the stated values ​​may also be within the scope of the invention, depending on the specific application, for a better understanding of suitable sample embodiments.

[0044] Embodiments will now be described in detail with reference to the accompanying drawings. To avoid unnecessarily obscuring the current disclosure, well-known features may not be described, or substantially the same elements may not be repeated. This is for ease of understanding.

[0045] The following description is provided so that those skilled in the art can fully understand this disclosure and is by no means intended to limit the scope of the disclosure as set forth.

[0046] The embodiments described herein provide a novel backwashing system for multi-media filters to reduce fluid consumption during backwashing.

[0047] It is worth noting that the fluid mentioned throughout the instruction manual can be referred to as water interchangeably.

[0048] Furthermore, the multi-media filtration described herein is filtration using a variety of filter media, which can be collectively inferred to be multi-layer filtration using different media layers selected from filter sand, anthracite, and granite, for the filtration and purification of fluids (e.g., water).

[0049] As described herein, backwashing is a process of cleaning or washing a multi-media filter by reversing the flow of backwash fluid at increased speed and pressure to release trapped impurities to be removed from the multi-media filter.

[0050] The fluidization described in this article is the liquefaction process of a granular filter layer in a multi-media filter, which causes solid particles to float in an upward direction or in the opposite direction to the flow of the fluid being filtered.

[0051] According to an embodiment of the invention, referring to the accompanying drawings, where similar features are indicated by similar numbers, the novel backwashing system for a multi-media filter according to the invention is generally indicated by reference numeral 10.

[0052] like Figure 2 , Figure 3 and Figure 4 As shown in the best embodiment, the backwashing system 10 includes: - Filter container 20, which has: a fluid inlet 30 located in the top region of operation for supplying fluid containing impurities to the filter container 20; and a fluid outlet 40 located in the bottom region of operation for conveying filtered fluid out of the filter container 20. - Particulate filter layers 50A, 50B and 50C are arranged in the filter container 20 and located between the fluid inlet 30 and the fluid outlet 40. The particulate filter layers 50A, 50B and 50C are used to filter impurities from the fluid. - A bottom distributor 60, which is in fluid flow communication with the backwash fluid supply 70, is arranged at the bottom region of the filter container 20 during operation; and Auxiliary distributors 80A, 80B, and 80C are arranged horizontally within each granular filter layer 50A, 50B, and 50C, wherein the auxiliary distributors 80A, 80B, and 80C are in fluid flow communication with the backwash fluid supply 70, and are used to introduce backwash fluid into each of the granular filter layers 50A, 50B, and 50C. The backwashing system 10 is characterized by independently backwashing each of the granular filter layers 50A, 50B, and 50C via horizontal auxiliary distributors 80A, 80B, and 80C, depending on the requirements of the granular filter layers 50A, 50B, and 50C, and backwashing the entire filter container 20 in combination with the bottom distributor 60, thereby reducing the consumption of backwash fluid used in the backwashing process and reducing the hydraulic resistance within the filter container 20.

[0053] The backwashing system 10 includes a fluid handling system in the form of a multi-media filter container 20 for treating (i.e. filtering) fluids containing impurities. The impurities are in the form of suspended solids and / or particles. Suspended solids and / or particles are typically silt, clay, gravel, organic matter, algae, and / or other microorganisms.

[0054] The multi-media filter container 20 is a pressurized container and includes a base 20A for vertically supporting the multi-media filter container 20. That is, the multi-media filter container 20 is supported by the base 20A, making it in the form of a vertical well.

[0055] During normal operation of the multimedia filter container 20, fluid containing impurities is supplied to it through the fluid inlet 30. After the fluid has been filtered by the multimedia filter container 20, the filtered fluid is discharged from the multimedia filter container 20 through the fluid outlet 40.

[0056] During the backwashing process of the multimedia filter container 20, the fluid inlet 30 of the multimedia container 20 serves as the fluid outlet of the backwash fluid. Similarly, during the backwashing process of the multimedia filter container 20, the fluid outlet 40 of the multimedia filter container 20 serves as the fluid inlet of the backwash fluid.

[0057] like Figure 4 As shown, three separate granular filter layers 50A, 50B, and 50C are disposed within the multi-media filter container 20. The three granular filter layers 50A to 50C are stacked on top of each other and located between the fluid outlet 40 and the fluid inlet 30 of the multi-media filter container 20. The granular filter layers 50A to 50C are used to capture and filter impurities from untreated fluid to provide filtered or cleaned fluid. The first granular filter layer 50A is located in the bottom region of the multi-media filter container 20 during operation, the second granular filter layer 50B is located above the first granular filter layer 50A, and the third granular filter layer 50C is located above the second granular filter layer 50C. Each granular filter layer 50A to 50C contains granular filter media with a density and size different from those of the granular filter media constituting the other two granular filter layers. The granular filter media of the first granular filter layer 50A has a higher density than the granular filter media constituting the second granular filter layers 50B and the third granular filter layer 50C. The density of the granular filter medium in the third granular filter layer 50C is lower than that of the granular filter media constituting the first granular filter layers 50A and 50B. The granular filter medium constituting the first granular filter layer 50A is also generally finer than the filter media constituting the second granular filter layers 50B and 50C. Similarly, the granular filter medium constituting the third granular filter layer 50C is generally coarser than the granular filter media constituting the first granular filter layers 50A and 50B.

[0058] The first granular filter layer 50A of the multi-media filter container 20 contains garnet or gravel. Its small particles are used to capture and filter very fine impurities in the fluid to be treated.

[0059] The second granular filter layer 50B of the multi-media filter container 20 contains sand.

[0060] The third granular filter layer 50C of the multi-media filter container 20 contains anthracite. Its coarse particles are used to capture and filter larger impurities (compared to the size of impurities captured and filtered in the first granular filter layers 50A and 50B) in the fluid to be treated.

[0061] The bottom distributor 60 supplies backwash fluid to the multimedia filter container 20 during the backwashing process to fluidize the granular filter layers 50A to 50C. The bottom distributor 60 is a sprayer configured to uniformly distribute the backwash fluid to the bottom region of the multimedia filter container 20 and upward toward the first granular filter layer 50A.

[0062] The sprayer 60 is in fluid flow communication with the fluid outlet 40 of the multimedia filter container 20 and the backwash fluid supply 70. However, those skilled in the art will understand that the sprayer 60 may also be in fluid flow communication with a dedicated backwash fluid outlet (not shown), which in turn is in fluid flow communication with the backwash fluid supply 70. The backwash fluid supply 70 includes a pump 72 that pumps backwash fluid from the container (not shown) to the fluid outlet 40 of the multimedia filter container 20 and through the sprayer 60 during the backwash process. The backwash fluid is pumped to the sprayer 60 at a pressure higher than the dominant ambient pressure.

[0063] Horizontally arranged auxiliary distributors 80A, 80B, and 80C are positioned within each granular filter layer 50A, 50B, and 50C. The auxiliary distributors 80A, 80B, and 80C are also in fluid flow communication with the backwash fluid supply 70. During the backwashing process, backwash fluid is supplied to each granular filter layer 50A, 50B, and 50C via the auxiliary distributors 80A, 80B, and 80C to fluidize the granular filter layers 50A, 50B, and 50C. The auxiliary distributors 80A, 80B, and 80C include nozzles and / or pulsators 82A, 82B, and 82C for distributing backwash fluid from within each granular filter layer 50A, 50B, and 50C and upward toward the top region of the multi-media filter container 20.

[0064] Sensors are disposed in and around the multi-media filter container 20. These sensors include pressure sensors 92A, 92B, 92C, and 92D, a temperature sensor (not shown), and flow rate sensors 94A, 94B, 94C, and 94D. Pressure sensors 92A to 94D monitor the pressure within the multi-media filter container 20, while the temperature sensors monitor the temperature of the backwash fluid, the fluid to be filtered, and / or the granular filter layers 50A to 50C. For each granular filter layer 50A, 50B, and 50C, at least one pressure sensor is disposed below and above the respective filter layer. Pressure sensors 92A, 92B, 92C, and 92D calculate the pressure difference across the granular filter layers 50A, 50B, and 50C, respectively.

[0065] Various flow rate sensors 94A, 94B, 94C, and 94D are configured to monitor the flow rate of backwash fluid to sprayer 60 and / or auxiliary distributors 80A, 80B, and 80C. Flow rate sensor 94A monitors the flow rate of backwash fluid to sprayer 60. Flow rate sensor 94B monitors the flow rate of backwash fluid to nozzle 82A of the first auxiliary distributor 80A. Flow rate sensor 94C monitors the flow rate of backwash fluid to nozzle 82B of the second auxiliary distributor 80B. Flow rate sensor 94D monitors the flow rate of backwash fluid to nozzle 82C of the third auxiliary distributor 80C.

[0066] A flow rate sensor 100E is configured to measure the flow rate of the fluid to be filtered by the multimedia filter container 20. However, during the backwashing process of the multimedia filter container 20, the flow rate sensor 100E is configured to measure the flow rate of the backwash fluid leaving the multimedia filter container 20.

[0067] The sensor is an electronic sensor configured to wirelessly network and communicate with a control system (not shown).

[0068] Valves are provided for controlling the flow rate of fluid to and from the multi-media filter container 20 (i.e., the fluid to be filtered and the backwash fluid). At least one valve is provided in each conduit supplying the backwash fluid to the sprayer 60 and auxiliary distributors 80A to 80C. Valves 100A, 100B, 100C, and 100D are configured to be wirelessly networked and connected to the control system. Valves 100A to 100D include electronic actuators (not shown) for closing and opening valves 100A to 100D. The electronic actuators of valves 100A to 100D are configured to be operable from the control system 200. In other words, electronic signals can be sent from the control system 200 to valves 100A to 100D to close or open them, thereby controlling the flow rate of the backwash fluid through them.

[0069] The control system 200 includes a computing environment 200.

[0070] like Figure 5As shown, computing environment 200 includes: - Communication module 230 is used to receive electronic communication signals from sensors 92A to 92D and 94A to 94D and valves 100A to 100D and to send electronic communication signals to sensors 92A to 92D and 94A to 94D and valves 100A to 100D and / or their respective electronic actuators. - Storage module 220, for storing computer-readable instructions related to the operation of the multi-media filter container 20; - Central processing unit 210 is used to retrieve computer-readable instructions from storage module 220, and to process the computer-readable instructions and received electronic communication signals to provide output data. The output data is in the form of electronic communication signals sent to sensors 92A to 92D, 94A to 94D and valves 100A to 100D and / or their respective electronic actuators.

[0071] Storage module 230 is any one or a combination of removable storage devices, non-removable storage devices, random access memory devices, read-only memory devices, erasable programmable read-only memory devices, electrically erasable programmable read-only memory devices, flash memory devices, optical disc read-only memory devices, digital multifunction disks or other optical disc storage devices, magnetic tape devices, and disk storage devices.

[0072] Communication module 230 includes a transceiver for sending and receiving electronic communication signals to and from various sensors 92A to 92D, 94A to 94D, and valves 100A to 100D and / or their respective electronic actuators. The electronic communication signals are transmitted via a wireless communication network (i.e., an example of networked communication). However, those skilled in the art will understand that any number of networked communication protocols can be used to establish an electronic communication network between the various sensors 92A to 92D, 94A to 94D, and valves 100A to 100D of the multi-media filter container 20 and the computing environment 200.

[0073] Central processing unit 210 is configured to retrieve computer-readable instructions from storage module 220 and electronic communication signals received by communication module 230 from various sensors 92A to 92D, 94A to 94D, and valves 100A to 100D of multi-media filter container 20. Once retrieved, central processing unit 210 is configured to process the electronic communication signals and computer-readable instructions to provide output data. The output data takes the form of electronic communication signals sent to the electronic actuators of one of the valves 100A to 100D of multi-media filter container 20. The electronic communication signals cause valves 100A to 100D to partially or fully open or close. In this way, the flow rate of backwash fluid to sprayers 60 and / or auxiliary distributors 80A to 80C can be controlled. This allows a user of computing environment 200 to remotely control the backwashing procedure of multi-media filter container 20 from control system 200.

[0074] The output data is an electronic communication signal sent to the electronic actuator of valve 100. For example, the electronic communication signal causes valve 100 to partially or fully open or close to control the flow rate of fluid through valve 100 and into or out of multi-media filter container 20.

[0075] The computing environment 200 also includes input devices 240 and output devices 250 to allow users of the computing environment 200 to interact with it. This allows users to initiate, control, monitor, and / or stop the backwashing process of the multi-media filter container 20.

[0076] Figure 5 The computing environment 200 shown is a physical computing environment. However, those skilled in the art will understand that the computing environment 200 can also be a virtual computing environment.

[0077] Computer-readable instructions stored on storage module 220 of computing environment 200 are configured to allow central processing unit 210 to compare different electronic communication signals received from various sensors 92A to 92D, 94A to 94D and valves 100A to 100D. These electronic communication signals are typically readings or measurements acquired by the various sensors 92A to 92D, 94A to 94D and valves 100A to 100D of multi-media filter container 20.

[0078] The computer-readable instructions are also configured to allow the computing environment 200 to define various minimum and maximum parameters (e.g., pressure loss, temperature, fluid and backwash fluid flow rates, etc.) that the multimedia filter container 20 must operate within. Those skilled in the art will understand that these predefined parameters will be unique for each multimedia filter container 20. Furthermore, the predefined parameters may also be changed for the multimedia filter container 20 during its operational life. This is because the predefined parameters inherently depend on the complex interactions between multiple factors. These factors include, but are not limited to: - The quality of the inlet fluid to be filtered by the multi-media filter container 20; - The required outlet quality of the fluid that has been filtered by the multi-media filter container 20; - The type (size, density, and / or inherent or reactive chemical and / or biological properties) of the granular filter media used for different granular filter layers in the multi-media filter container 20; - The number of granular filter layers in the multi-media filter container 20; - The pressure to which the fluid to be filtered by the multi-media filter container 20 is supplied; - The degree of scaling or clogging of the granular filter layer in the multi-media filter container 20; and - The quality and type of backwash fluid used in the backwashing process of the multi-media filter vessel 20.

[0079] Computer-readable instructions cause the central processing unit 210 to execute Figure 6 and Figure 7 The steps are shown in the figure.

[0080] like Figure 6 As shown, the method for controlling the backwashing procedure of the multi-media filter container 20 includes a first step 1000, which defines a maximum differential pressure threshold (ΔP) for each, all, or some of the granular filter layers 50A to 50C. MAX ) and minimum differential pressure threshold (ΔP) MIN As previously mentioned, this is accomplished via the input device 240 of the computing environment 200. Maximum differential pressure threshold (ΔP) MAX ) and minimum differential pressure threshold (ΔP) MIN The value is stored on the storage module 220 of the computing environment 200.

[0081] Then, the method for controlling the backwashing procedure of the multi-media filter container 20 includes a further step 2000 for measuring the differential pressure (ΔP) across the granular filter layers 50A to 50C. MEASURED ).

[0082] like Figure 6As shown, during the following steps 3000A and 3000B, the central processing unit 210 will measure the differential pressure (ΔP) MEASURED ) and the maximum differential pressure threshold (ΔP) stored in the storage module 220 of the computing environment 200. MAX ) and minimum differential pressure threshold (ΔP) MIN The values ​​are compared.

[0083] If the measured differential pressure (ΔP) MEASURED ) equal to or greater than the preset maximum differential pressure threshold (ΔP) MAX If the backwashing procedure is initiated, the method for controlling the backwashing process continues to step 4000 to initiate the backwashing procedure. If the measured differential pressure (ΔP) MEASURED ) equal to or less than the preset minimum differential pressure threshold (ΔP) MIN If the backwashing procedure is stopped, the method for controlling the backwashing process continues to step 5000 to stop the backwashing process of the multi-media filter container 20.

[0084] The method also includes a further step 6000 for recording the date and time of initiating and / or stopping the backwashing procedure of the multi-media filter container 20.

[0085] like Figure 7 As shown, the method for controlling the backwashing procedure of the multi-media filter container 20 further includes a further step 8000 for limiting a minimum value (ΔV) of the backwash fluid flow rate flowing through the sprayers 60 and / or auxiliary distributors 80A to 80C and from their nozzles 82A to 82C. MIN_THRESHOLD ) and entrainment value (or maximum value) (ΔV) MAX_THRESHOLD As previously mentioned, this is accomplished using the input device 240 of the computing environment 200. Minimize (ΔV) MIN_THRESHOLD ) and entrainment (or maximum) (ΔV) MAX_THRESHOLD The backwash fluid flow rate is stored in the storage module 220 of the computing environment 200.

[0086] like Figure 7 As shown, during the next steps 10000A and 10000B, the central processing unit 210 will measure the backwash fluid flow rate (V). MEASURED ) and the minimum (ΔV) stored in the storage module 220 of the computing environment 200. MIN_THRESHOLD ) and entrainment (or maximum) (ΔV) MAX_THRESHOLD The backwash fluid flow rates were compared.

[0087] If the measured backwash fluid flow rate (V) MEASURED The backwash fluid flow rate is equal to or less than the predetermined minimum backwash fluid flow rate (ΔV). MIN_THRESHOLDIf the backwashing process continues, the method of controlling the backwashing process continues to step 12000, which involves increasing the flow rate of the backwash fluid flowing through the sprayers 60 and / or auxiliary distributors 80A to 80C and from their nozzles 82A to 82C. The backwash fluid flow rate is increased until the measured backwash fluid flow rate (V) is reached. MEASURED Exceeding the predefined minimum backwash fluid flow rate (ΔV) MIN_THRESHOLD Up to 20%.

[0088] If the measured backwash fluid flow rate (V) MEASURED The entrainment (or maximum) backwash fluid flow rate (ΔV) is equal to or greater than the predetermined entrainment (or maximum) backwash fluid flow rate. MAX_THRESHOLD If the backwashing process continues, then the method of controlling the backwashing process continues to the step 14000 of reducing the flow rate of the backwash fluid flowing through the sprayers 60 and / or auxiliary distributors 80A to 80C and from their nozzles 82A to 82C. The backwash fluid flow rate is reduced until the measured backwash fluid flow rate (V) is reached. MEASURED The backwash fluid flow rate is lower than the predefined entrainment (or maximum) flow rate (ΔV). MAX_THRESHOLD Up to 20%.

[0089] Examples of the advantages of the present invention

[0090] The following examples are provided to illustrate some advantages of the invention. They should not be construed as limiting the scope of the invention in any way.

[0091] One of the main advantages of this invention is that the multi-media filter container 20 of this invention requires far less fluid in the backwashing process compared to the backwashing procedures of conventional or known multi-media filters.

[0092] You can refer to Figure 1 , 2 The multi-media filter shown in Scenario 4 (i.e., three different scenarios) illustrates this advantage. The fluid reduction required during the backwashing process of the multi-media filter container 20 can be estimated as the difference between the fluid requirements of the first, second, and third scenarios. This fluid reduction can be calculated using the following formula:

[0093] In the above formula, V1 is the fluid volume required to backwash the first multi-media filter, and V2 is the fluid volume required to backwash the second multi-media filter. For example, backwashing... Figure 1 The required fluid volume and backwashing of the multi-media filter 1000 shown are as follows. Figure 2 The fluid volume required for the multi-media filter shown.

[0094] To calculate the required reduction in fluid volume for backwashing a multi-media filter, the following calculations and assumptions are also required: - A single layer (i.e., a single granular filter layer) within a multi-media filter 1000 or 10; - The backwash fluid flow rate must be selected through sprayer 1010 or 60 and auxiliary distributors 80A to 80C; - The Reynolds number for each backwash fluid flow must be calculated; - The porosity of the single layer (i.e., granular filter layers 50A to 50C) that has been fluidized during the backwashing process must be calculated; and - The height of the single layer (i.e., granular filter layers 50A to 50C) that has been fluidized during the backwashing process must be calculated.

[0095] For all three different scenarios, the following assumptions were made: - The temperature remains constant throughout the multi-media filter; - The density of the fluid flowing into and out of the multi-media filter is constant (ρ w =1000kg / m 3 ); - The viscosity of the fluid flowing into and out of the multi-media filter is constant (μ). w =1.0024·10 -3 Pa·s); - The granular particles in a single filter layer are spherical particles (Φ=1); - The porosity of a single filter layer is 0.4 (ε0=0.4); - All granular particles in a single filter layer have the same diameter (d0 = 3 mm); - The diameter of the multi-media filter is 0.75m; - The height (h0) of a single filter layer is 1.4m; and - Density of granular particles in a single filter layer (ρ) p ) is 1500 kg / m 3 .

[0096] The calculations described above are illustrated below for each scenario.

[0097] Scene 1

[0098] like Figure 1 As shown, the multi-media filter 1000 in the first scenario is a conventional multi-media filter, which includes a single sprayer 1010 located in the bottom region of the multi-media filter 1000 for introducing backwash fluid into the multi-media filter 1000.

[0099] The single-particle filter layer includes granular filter layers 1004a to 1004c.

[0100] In this first scenario, it is assumed that: - The height (h0) of the single-particle filter layer is 1.4m; and - The flow rate (V) of the backwash fluid from sprayer 1010 is 35m. 3 / h.

[0101] The cross-section (S) of the multi-media filter 1000 can be calculated as follows:

[0102] The apparent velocity through the multi-media filter 1000 can be calculated as follows:

[0103] The channel speed can be calculated as follows:

[0104] The Reynolds number can be estimated as follows:

[0105] Archimedes numbers The calculation can be performed as follows:

[0106] The porosity of the fluidized granular filter layer (i.e., the granular filter layers 1004a to 1004c as a single layer) can be calculated as follows:

[0107] The height of the fluidized granular filter bed can be calculated as follows:

[0108] The volume of the fluidized granular filter bed can be calculated as follows:

[0109] The coefficient of thermal expansion can be calculated as follows:

[0110] Then Figure 1 The volume of fluid required during the backwashing procedure of the multi-media filter 1000 shown can be calculated as follows:

[0111] Second Scene

[0112] like Figure 2 As shown, the multi-media filter 10 in the second scenario includes a bottom distributor in the form of a sprayer 60 and an auxiliary distributor 80A arranged within the granular filter layer 50A. The auxiliary distributor 80A distributes backwash fluid upward from within the granular filter layer to fluidize the granular filter layer.

[0113] The single-particle filter layer in this second scenario includes granular filter layers 50A to 50C.

[0114] In this second scenario, we assume: - The height (h1) of the single-particle filter layer located below the auxiliary distributor 80A is 0.7m; - The height (h2) of the single-particle filter layer located above the auxiliary distributor 80A is 0.7m; - The flow rate (V1) of the backwash fluid to and from the sprayer 60 is 17.5 m. 3 / h; and - The flow rate (V2) of the backwash fluid to and from the auxiliary distributor 80A is 17.5 m. 3 / h.

[0115] The granular filter media in the granular filter layer located below the supplementary fluid distributor 80A refers to: The apparent velocity can be calculated as follows:

[0116] Channel speed can be calculated as follows:

[0117] Reynolds number The following estimation can be made:

[0118] The porosity of fluidized granular filter media can be calculated as follows:

[0119] The height of fluidized granular filter media can be calculated as follows:

[0120] The volume of fluidized granular filter media can be calculated as follows:

[0121] The granular filter media in the granular filter layer located above the supplementary fluid distributor 80A refers to (without sprayers) 60)： In the calculations below, the flow of backwash fluid from below the auxiliary distributor 80A is excluded. Only the flow of backwash fluid from the auxiliary distributor 80A is used. This allows one to evaluate the effect of the auxiliary distributor 80A on the particulate filter media located above the nozzle 82A of the auxiliary distributor 80A.

[0122] The apparent velocity can be calculated as follows:

[0123] Channel speed can be calculated as follows:

[0124] Reynolds number The following estimation can be made:

[0125] The porosity of fluidized granular filter media can be calculated as follows:

[0126] The height of fluidized granular filter media can be calculated as follows:

[0127] The volume of fluidized granular filter media can be calculated as follows:

[0128] The granular filter media of the granular filter layer located above the supplementary fluid distributor 80A refers to (with sprayer 60): In the calculations below, the flow of backwash fluid from below the auxiliary distributor 80A (in other words, the flow of backwash fluid from the sprayer 60) and the flow of backwash fluid from the auxiliary distributor 80A are used together. This allows one to evaluate the combined effect of the backwash fluid flows from the sprayer 60 and the auxiliary distributor 80A.

[0129] Here, we assume the following:

[0130] The apparent velocity can be calculated as follows:

[0131] The channel speed can be calculated as follows:

[0132] The Reynolds number can be estimated as follows:

[0133] The porosity of fluidized granular filter media can be calculated as follows:

[0134] The height of fluidized granular filter media can be calculated as follows:

[0135] The volume of fluidized granular filter media can be calculated as follows:

[0136] Summary of the second scenario:

[0137] Therefore, backwashing Figure 2 The required fluid volume for the multi-media filter 10 shown can be calculated as follows:

[0138] So, when it comes to anti-washing Figure 1 Compared to the fluid required for backwashing in a multi-media filter 1000 Figure 2 The required fluid reduction for the multi-media filter 10 can be calculated as follows:

[0139] Third Scene

[0140] like Figure 4 As shown, the multi-media filter 10 in the third scenario includes a bottom distributor in the form of a sprayer 60 and three auxiliary distributors 80A to 80C arranged within the granular filter layers 50A to 50C. The auxiliary distributors 80A to 80C distribute backwash fluid upward from within the granular filter layers to fluidize the granular filter layers.

[0141] The single-particle filter layer in this third scenario includes particle filter layers 50A to 50C.

[0142] In this third scenario, we assume: - The height of the single-particle filter layer located below the first auxiliary distributor 80A ( h 1 The value is 0.5m; - The height of the single-particle filter layer located between the first auxiliary distributor 80A and the second auxiliary distributor 80B ( h 2 The value is 0.5m; - The height of the single-particle filter layer located above the third auxiliary distributor 80C ( h 3 The value is 0.4m; - The flow rate of the backwash fluid to and from the first auxiliary distributor 80A ( V 1 The value is 11.67 m. 3 / h; - The flow rate of the backwash fluid to and from the second auxiliary distributor 80B ( V 2 The value is 11.67 m. 3 / h; and - The flow rate of the backwash fluid to and from the third auxiliary distributor 80C ( V 3 The value is 11.67 m. 3 / h.

[0143] The granular filter media of the granular filter layer located below the first auxiliary distributor 80A: The apparent velocity can be calculated as follows:

[0144] The channel speed can be calculated as follows:

[0145] The Reynolds number can be estimated as follows:

[0146] The porosity of fluidized granular filter media can be calculated as follows:

[0147] The height of fluidized granular filter media can be calculated as follows:

[0148] The volume of fluidized granular filter media can be calculated as follows:

[0149] The granular filter media (without sprayer 60) of the granular filter layer located below the second auxiliary distributor 80B: In the calculations below, the flow of backwash fluid below the second auxiliary distributor 80B is excluded. Only the flow of backwash fluid from the second auxiliary distributor 80B is used. This allows for the evaluation of the effect of the second auxiliary distributor 80B on the particulate filter media located above the nozzle 82B of the second auxiliary distributor 80B.

[0150] The apparent velocity can be calculated as follows:

[0151] Channel speed can be calculated as follows:

[0152] Renault The number can be estimated as follows:

[0153] The porosity of fluidized granular filter media can be calculated as follows:

[0154] The height of fluidized granular filter media can be calculated as follows:

[0155] The volume of fluidized granular filter media can be calculated as follows:

[0156] The granular filter media located below the second auxiliary distributor 80B (without the sprayer 60) in the granular filter layer: The calculations below include the flow of backwash fluid from below the second auxiliary distributor 80B (in other words, the backwash fluid from the sprayer 60 and the first auxiliary distributor 80A). This allows for the evaluation of the combined effect of the backwash fluid flows from the sprayer 60, the first auxiliary distributor 80A, and the second auxiliary distributor 80B.

[0157] In the calculations below, the flow of backwash fluid from below the auxiliary distributor 80A (in other words, the flow of backwash fluid from the sprayer 60) and the flow of backwash fluid from the auxiliary distributor 80A are used. This allows for the evaluation of the combined effect of the backwash fluid flows from the sprayer 60 and the auxiliary distributor 80A.

[0158] Here, we assume the following:

[0159] Apparent velocity can be calculated as follows:

[0160] Channel speed can be calculated as follows:

[0161] Renault The number can be estimated as follows:

[0162] The porosity of fluidized granular filter media can be calculated as follows:

[0163] The height of fluidized granular filter media can be calculated as follows:

[0164] The volume of fluidized granular filter media can be calculated as follows:

[0165] The granular filter media located below the third auxiliary distributor 80C (with sprayer 60) in the granular filter layer. : In the calculations below, backwash fluid flow from below the third auxiliary distributor 80C was used (in other words, backwash fluid flow from the sprayer 60, and backwash fluid flow from the first 80A and the second auxiliary distributor 80B). This allows for the evaluation of the combined effect of the backwash fluid flows from the sprayer 60, the first auxiliary distributor 80A, and the second auxiliary distributor 80B.

[0166] Here, we assume the following:

[0167] Apparent velocity can be calculated as follows:

[0168] Channel speed can be calculated as follows:

[0169] Renault The number can be estimated as follows:

[0170] The porosity of fluidized granular filter media can be calculated as follows:

[0171] The height of fluidized granular filter media can be calculated as follows:

[0172] The volume of fluidized granular filter media can be calculated as follows:

[0173] Summary of the third scenario:

[0174] Therefore, backwashing Figure 3 The required fluid volume for the multi-media filter 10 shown can be calculated as follows:

[0175] With backwashing Figure 1 Compared to the fluid required for backwashing in a multi-media filter 1000, Figure 3 The required reduction in fluid volume for the multi-media filter 10 can be calculated as follows:

[0176] As can be clearly seen from the above calculations, the multi-media filter backwashing system and the method for backwashing the system of the present invention have significant and surprising advantages compared with the prior art, namely, the fluid volume required for backwashing the multi-media filter is greatly reduced compared with conventional fluid handling systems and methods for backwashing such systems.

Claims

1. A novel backwashing system for multi-media filters is provided to reduce fluid consumption during the backwashing process of the multi-media filter, wherein the system comprises: - A filter container having a fluid inlet located at the top of the operating area for supplying fluid containing impurities into the filter container, and a fluid outlet located at the bottom of the operating area of ​​the filter container for discharging filtered fluid out of the filter container. - A granular filter layer is arranged inside the filter container and located between the fluid inlet and the fluid outlet, the granular filter layer being used to filter impurities from the fluid; - A bottom distributor, which is in fluid flow communication with the backwash fluid supply device, is arranged in the bottom area of ​​the filter container during operation; and - Auxiliary distributors, arranged horizontally to be positioned within each granular filter layer, wherein the auxiliary distributors are in fluid flow communication with the backwash fluid supply device, and wherein they are used to introduce backwash fluid into each granular filter layer. The backwashing system is characterized in that, depending on the requirements of the granular filter layers, each granular filter layer is backwashed independently by a horizontal auxiliary distributor, and the entire filter container is backwashed in combination with a bottom distributor, thereby reducing the consumption of backwash fluid used during the backwashing process and reducing the hydraulic resistance within the filter container.

2. The backwashing system of claim 1, wherein the backwashing causes fluidization of the granular filter layer to release impurities trapped within the filter layer.

3. The backwashing system of claim 1, wherein the bottom distributor comprises a sprayer for uniformly distributing fluid from the bottom region of the filter container upward toward the top of the filter container, an annular rotating device, a duct, a transverse system comprising transverse pipes or channels branching from the central manifold, a pulsator, or a nozzle.

4. The backwashing system of claim 1, wherein a plurality of granular filter layers are disposed within the filter container and arranged between its fluid inlet and fluid outlet, and wherein each of the plurality of granular filter layers comprises a granular filter medium having a size and density different from that of the other granular filter layers.

5. The backwashing system according to claim 1, wherein the first auxiliary distributor is located within the first granular filter layer, the second auxiliary distributor is located within the second granular filter layer, and the third auxiliary distributor is located within the third granular filter layer.

6. The backwashing system of claim 5, wherein the first auxiliary distributor, the second auxiliary distributor, and the third auxiliary distributor comprise a sprayer, a ring-shaped rotating device, a pulsator, or a nozzle for distributing fluid from within the associated granular filter layer upward toward the fluid inlet of the filter container.

7. The backwashing system of claim 1, wherein the system further comprises a sensor for monitoring the volume and flow rate of backwash fluid from the bottom distributor and the auxiliary distributor, and for measuring the differential pressure across the granular filter layer of the system.

8. The backwashing system of claim 7, wherein the sensor is an electronic sensor that is networked and communicates with a computing environment.

9. The backwashing system of claim 1, wherein the system includes various valves for controlling the flow rate of backwash fluid from the bottom distributor and the auxiliary distributor.

10. The backwashing system of claim 9, wherein the valve is an electronic valve including an electronic actuator, the electronic valve being networked and communicating with a computing environment, and the electronic actuator of the valve being configured to close and open the associated valve upon receiving an electronic communication signal from the computing environment.

11. The backwashing system according to claim 10, wherein the computing environment includes: - A communication module used to receive electronic communication signals from electronic sensors and valves and send those signals back to the sensors and valves; - A storage module for storing computer-readable instructions related to the operation of the backwashing system; and - A central processing unit used to retrieve computer-readable instructions from storage modules and process those instructions to provide output data. The output data is in the form of electronic communication signals to the sensor and valve.

12. A method for controlling the backwashing procedure of the system according to claim 1, the method comprising the following steps: - The differential pressure across the granular filter layer is measured by comparing pressure readings from a pressure sensor located near the bottom surface of the granular filter layer with pressure readings from a pressure sensor located near the top surface of the granular filter layer; - Compare the measured differential pressure across the granular filter layer with a predetermined maximum differential pressure across the granular filter layer and a predetermined minimum differential pressure across the granular filter layer; - If the measured differential pressure across the granular filter layer is equal to or greater than the predetermined maximum differential pressure across the granular filter layer, then the backwashing procedure of the system is initiated; as well as If the measured differential pressure across the granular filter layer is equal to or less than a predetermined minimum differential pressure, then the backwashing procedure of the system is stopped.

13. The method of claim 12, wherein, The backwashing process of the system is initiated by opening the valves that control the flow of backwash fluid from the backwash fluid supply unit to the bottom distributor and auxiliary distributor.

14. The method according to claim 13, wherein, After the backwashing procedure of the system has been initiated, the method for controlling the backwashing procedure of the multi-media filter includes the following additional steps: - The flow rate of backwash fluid leaving the bottom distributor and the auxiliary distributor is measured by a fluid flow sensor; - Compare the measured backwash fluid flow rate with a predefined minimum backwash fluid flow rate threshold and a predefined maximum backwash fluid flow rate threshold; - If the measured backwash fluid flow rate is equal to or greater than the preset maximum backwash fluid flow rate threshold, then reduce the backwash fluid flow rate through the bottom distributor and the auxiliary distributor; as well as If the measured backwash fluid flow rate is equal to or less than the predetermined minimum backwash fluid flow rate, then increase the backwash fluid flow rate through the bottom distributor and the auxiliary distributor.

15. The method according to claim 14, wherein, Reduce the backwash fluid flow rate through the bottom distributor and the auxiliary distributor until it is below 20% of the predetermined maximum backwash fluid flow rate.

16. The method of claim 14, wherein, Increase the fluidization flow rate through the bottom distributor and the auxiliary distributor until it exceeds the predetermined minimum backwash fluid flow rate by 20%.

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