Renewable systems and methods for filtering microfibers from wastewater

Abstract

The present invention relates to a renewable system and method for filtering microfibers contained in effluent from textile processing equipment. The system includes at least one housing (10) for holding particulate media (30), a channel device (100) for percolating the effluent through the particulate media, a device (110) located below the particulate media (30) for discharging the effluent, and a device (120) for connecting a fluidized regeneration device for the particulate media (30).

Description

Invention Field

[0001] This invention relates to the field of removing microfibers contained in the effluent of textile processing equipment (such as washing machines, laundry rooms (industrial or non-industrial), textile dyeing equipment, or waterproof textile equipment).

[0002] Recent studies have shown that 20% to 35% of microplastics found in the marine environment originate from microfibers in synthetic clothing. These microplastics are primarily released as microfibers during the washing of synthetic textiles due to abrasion of the fabric during the washing cycle. Therefore, each time a household washing machine is used, more than 700,000 microfibers are released into the wastewater, a significant portion of which may eventually enter the environment after wastewater treatment.

[0003] More precisely, according to some studies, the amount of fibers released during textile washing may be equivalent to 0.005 to 0.02 wt% of the textiles being washed, depending on the nature of the textiles. Other studies suggest that, depending on the nature of the textiles, the amount of fibers released during textile washing may even be equivalent to 0.02 to 0.1 wt% of the textiles being washed.

[0004] Therefore, this is also a significant public health issue because these microplastics are present in the water and food we consume. According to the latest estimates, the average person ingests 5 grams of plastic per week, which is the weight of a credit card.

[0005] Furthermore, on January 30, 2020, France passed an anti-waste and circular economy law, Article 10.2AAB of which stipulates that from January 1, 2025, new washing machines must be equipped with plastic microfiber filters. France is the first country in the world to take such a measure. Background Technology

[0006] Document US-4,906,367 describes a flexible braided filter installed at the drain pipe of a washing machine. Major impurities, such as lint, are trapped by the filter, which requires physical removal and cleaning when clogged. The filter described in this document was originally intended to protect wastewater pipes, not to trap tiny objects like microfibers. In fact, the pores of the filter are not fine enough to achieve effective trapping. Using small pores in this type of filter quickly leads to clogging and a short filter life.

[0007] Also known is patent application WO-2017 / 173,215, which describes a spherical plastic object placed in a washing machine drum along with the laundry. Due to its multiple protrusions, it can capture released fibers in situ. However, the geometry of these protrusions has not been designed to capture small objects such as microfibers; the retention efficiency for microfibers longer than 100 μm is only 26%.

[0008] Patent application WO-2017 / 121,862 describes a woven filter plastic bag that can hold laundry and trap some textile microfibers. The bag has perforations with a diameter between 5 and 200 μm, preferably 50 μm. While this addresses the microfiber issue, it is questionable whether placing clothes inside the bag will not affect the washing effect. It is worth noting that dirt particles larger than microfibers will not be properly discharged. Placing clothes inside the bag may also reduce the mechanical efficiency of the drum. The document does not detail how some microfibers will not leak out again when the clothes are removed from the bag.

[0009] Patent application WO-2019 / 017,848 describes a system for trapping microfibers, located at the outlet of a washing machine, and based on a microfiltration membrane made of polyethylene nanofibers. The membrane preferably has a pore size of about 50 μm and may optionally be incorporated with alumina nanoparticles to enhance the adsorption capacity of the microfibers. The membrane filter described in the document has a certain degree of mobility, which provides anti-clogging functionality. However, despite this anti-clogging functionality, the lifespan of commercially available filter cartridges containing microfiltration membranes is currently limited to 20 washing cycles. Therefore, using such filters requires a large number of consumables, resulting in a significant consumption of plastic material for manufacturing these consumables. Furthermore, the plastic nanofibers constituting the membrane may deteriorate during use and are therefore discharged with the wastewater.

[0010] This invention relates to a system and method for efficiently and inexpensively filtering microfibers (plastics or other materials) at the outlet of a textile processing device, requiring very few consumables. In fact, the system according to the invention is regenerable, which can significantly reduce the periodic replacement of filters in the filtration system according to the invention. The system and method according to the invention can further collect at least a portion of the microfibers at the outlet of the textile processing device, creating possibilities for subsequent recycling. Summary of the Invention

[0011] This invention relates to a system for filtering microfibers contained in effluent from a textile processing apparatus, the system being intended to connect to the drain pipe of the textile processing apparatus. According to the invention, the system comprises at least:

[0012] - A housing (10) comprising a particulate medium occupying a portion of the space of the housing, the particulate medium being placed on a support to allow free volume above the particulate medium within the housing, the support being at least permeable to the effluent.

[0013] -A channel device that allows the effluent percolation through the particulate medium, comprising at least one opening provided in the housing (10) and positioned above the particulate medium.

[0014] - A device for discharging the effluent, comprising at least one opening provided within the housing and positioned below the support member of the particulate medium.

[0015] - A means for connecting to the fluidized regeneration apparatus for the particulate media includes at least one opening provided in the housing and positioned above the particulate media.

[0016] According to one embodiment of the invention, the device for connection to the particulate media fluidized regeneration apparatus includes an additional opening provided in the housing and positioned below a support member of the particulate media, the additional opening of the connection device being capable of being connected to a device for gas intake or gas blowing.

[0017] According to one embodiment of the invention, the device for discharging the effluent may include an external circuit connected to the housing to bypass the particulate medium when the effluent accumulates in the free volume above the particulate medium of the housing.

[0018] Alternatively, the device for discharging the effluent may include a conduit extending through the particulate medium to bypass the particulate medium when the effluent accumulates in the free volume of the housing above the particulate medium, the conduit preferably having a flow guide at its upper part.

[0019] According to one embodiment of the invention, the circuit (140) outside the housing may further include a liquid detector, preferably connected to an alarm.

[0020] According to one embodiment of the invention, the conduit (140) of the device (110) for discharging the effluent may further include a liquid detector, preferably connected to an alarm.

[0021] According to one embodiment of the present invention, the system may further include means for controlling the following: a channel means for percolating the effluent through the particulate media and / or a means for discharging the effluent and / or a means for connecting the particulate media fluidized regeneration device.

[0022] According to one embodiment of the present invention, the control device may include at least one two-way valve and / or at least one three-way valve and / or at least one check valve and / or a rotary six-way valve.

[0023] According to one embodiment of the invention, the system may further include a sedimentation chamber and / or a cyclone separation chamber and / or a storage chamber for the effluent, which are disposed upstream of the housing and connected to a channel device for percolating the effluent through the particulate medium.

[0024] According to one embodiment of the present invention, the system may further include means for injecting at least one flocculant into the effluent, the injection means being configured to inject the at least one flocculant into the effluent upstream of the particulate medium.

[0025] According to one embodiment of the present invention, the particulate medium may comprise sand, crushed glass beads or raw glass beads, particles based on natural or synthetic zeolite, alumina, or resin or plastic.

[0026] According to one embodiment of the present invention, the particulate medium comprises at least 80% by weight of particles having a size of 0.1 mm to 2 cm, preferably at least 90% by weight of particles having a size of 0.3 mm to 2.5 mm.

[0027] According to one embodiment of the present invention, a liquid distributor is provided between the particulate medium (30) and the opening (100) of the channel device (100) for the percolation of the effluent through the particulate medium (30), and / or when the fluidization regeneration device of the particulate medium (30) includes a gas suction device, a gas distributor is provided between the particulate medium (30) and the opening of the gas suction device for drawing in the gas.

[0028] The present invention further relates to a method for filtering microfibers contained in an effluent from a textile processing device, said method being implemented by a microfiber filtering system according to any of the above embodiments. The method comprises at least the following steps:

[0029] A) Performing at least one stage of filtering the microfibers, the filtration stage comprising passing the effluent through the particulate media at least once using at least a channel device for permeating the effluent through the particulate media, and discharging the filtered effluent using at least a device for discharging the effluent.

[0030] B) The stage of fluidized regeneration of particulate media is performed by connecting the device for connection to the fluidized regeneration device of particulate media.

[0031] According to one embodiment of the present invention, step A) may be repeated 50 to 150 times, preferably about 100 times, before step B).

[0032] According to one embodiment of the present invention, the method includes a step of pretreating the effluent before step A), the pretreating step of the effluent including injecting at least one flocculant into the effluent at least once and / or performing at least one sedimentation and / or performing at least one cyclone separation on the effluent.

[0033] According to one embodiment of the present invention, the method may include a stage prior to step B) in which the particulate medium is discharged using a gas suction device connected to the system to generate a downward airflow through the particulate medium, and / or a stage in which the particulate medium is dried using a device to increase the temperature of the particulate medium.

[0034] According to one embodiment of the present invention, the filtration and regeneration stages can be controlled by the aforementioned device for controlling the microfiber filtration system.

[0035] According to one embodiment of the invention, the method further includes at least one step following the fluidized regeneration stage, comprising collecting the microfibers from the regeneration stage, preferably via a membrane filter and / or cyclone chamber arranged downstream of the fluidized regeneration apparatus of the particulate medium (30).

[0036] The present invention also relates to a textile washing apparatus comprising at least one system for filtering microfibers contained in an effluent according to any of the above embodiments.

[0037] Brief description of the attached figures

[0038] - Figure 1 A microfiber filtration system according to a first embodiment of the present invention is shown.

[0039] - Figures 2a to 2f Microfiber filtration systems of different variations according to a first embodiment of the present invention are shown.

[0040] - Figures 3 to 6 7a to 7b show various embodiments of a device for controlling a microfiber filtration system according to the present invention.

[0041] - Figure 8 A microfiber filtration system is shown, the system comprising particulate media in the form of a three-stage granular bed, and,

[0042] - Figure 9 A microfiber filtration system is shown that can perform a particulate media drainage stage before the particulate media regeneration stage, followed by a particulate media drying stage. Detailed Implementation

[0043] This invention relates to a system and method for filtering microfibers contained in the effluent of a textile processing device.

[0044] "Microfibers" are understood to be particles from woven or knitted materials, composed of natural (cotton, wool, etc.) or synthetic (polyester, polyamide, acrylic, etc.) fibers, such as those used in clothing or fabrics in the apparel industry by private or industrial sectors, or for any other purpose (sheets, curtains, etc.). Microfibers are often found mixed in with washing machine wastewater and are typically elongated, with diameters generally between 0.1 and 50 micrometers. Fiber length can vary from the diameter of some fibers to several millimeters, depending on the nature and condition of the materials previously washed.

[0045] "Textile processing equipment" can be specifically understood as textile washing apparatus, such as a single washing machine, a group of washing machines (e.g., in a laundry room), an industrial laundry (e.g., a laundry room with staff), etc., for domestic or commercial use. However, textile processing equipment according to the invention generally includes any means of providing contact between the textile and a liquid, which is subsequently separated from the textile, such as textile dyeing apparatus or textile waterproofing apparatus.

[0046] "Effluent from at least one textile processing device" is understood to be the liquid obtained after exiting the textile processing device (e.g., in the case of textile washing equipment, the liquid after washing and / or rinsing and / or dehydration). It is referred to as "effluent" in the following context. Traditionally, the microfiber content in the effluent at the outlet of textile processing devices is typically limited, ranging from 0.1 to 1000 ppm (by weight), generally between 1 and 100 ppm (by weight).

[0047] The system according to the invention is intended to be connected to the drain pipe of a textile processing device. The system according to the invention can also be installed outside the textile processing device (at the end of the drain pipe of the textile processing device) or inside the textile processing device (on a portion of the drain pipe of the textile processing device).

[0048] The general principle of the filtration system according to the invention is that microfibers contained in the effluent from the textile processing equipment are filtered by percolation of the effluent through particulate media placed in the housing. The system according to the invention can be readily connected to a fluidized regeneration device for particulate media to eliminate microfibers deposited in the particulate media.

[0049] The method according to the invention generally includes at least one step of filtering microfibers contained in the effluent of the textile processing equipment by percolation of the effluent through particulate media placed in the housing, followed by regeneration by fluidization of the particulate media. Preferably, the regeneration step is carried out by an upward airflow of the particulate media, the upward gas preferably being air.

[0050] More specifically, the system according to the invention comprises a housing in which a portion of the space is occupied by the particulate medium, with a free volume within the housing above the particulate medium. According to the invention, the particulate medium is placed on at least one support member, which is permeable at least to the effluent and therefore also permeable to general gases (i.e., all gases), particularly gases suitable for regenerating the particulate medium via gas fluidization as described below. According to one embodiment of the invention, the support member for the particulate medium may be a mesh, the mesh size of which is capable of trapping the particulate medium while at least allowing the effluent to pass through.

[0051] The outer shell can be cylindrical or parallelepiped, and preferably elongated along the axis of the effluent flowing through the shell (i.e., the vertical axis, as described below). Advantageously, the cross-section of the shell can remain constant along the portion of the shell in contact with the particulate medium, while the cross-section can be larger, or even gradually increase, in the portion of the shell above the particulate medium. This increases the free volume above the particulate medium, which on the one hand avoids the risk of backflow when the effluent accumulates above the particulate medium (which may occur in the case of particulate medium blockage), and on the other hand improves the regeneration of the particulate medium by increasing the available volume for fluidized expansion and reducing the regeneration liquid flow rate above the particulate medium (limiting particle entrainment). The particulate medium according to the invention comprises at least one particle bed as described below.

[0052] The system according to the invention also includes a channel device for the percolation of effluent through the particulate medium. In other words, according to the invention, the particulate medium is traversed by the vertically downward effluent. This is achieved by having at least one opening in the upper part of the housing and above the particulate medium in the system according to the invention to allow the effluent to pass through. The term "upper part" is used relative to the downward flow direction of the effluent as it flows through the housing. Thus, the opening of the device providing the channel for the percolation of effluent through the particulate medium allows fibrous effluent to reach above the particulate medium. Advantageously, according to the invention, the opening of the device allowing the liquid effluent to percolate through the particulate medium is located on the upper wall of the system housing, preferably in the central portion of the upper wall (e.g., in a region centered on the centroid of the upper wall, with a radius equivalent to 30% of the minimum dimension of the upper wall). Compared to an eccentric opening, an opening located in the central portion of the upper wall of the housing results in a more uniform lateral distribution of the liquid effluent.

[0053] Furthermore, the system according to the invention also includes means for discharging effluent, said discharging means comprising at least one opening disposed in the lower part of the housing and below the support for the particulate media. The term "lower part" refers to the direction of downward flow of the effluent within the housing. Thus, the opening of the liquid discharging means provides an outlet for the effluent filtered by the particulate media, the outlet being located in the lower part of the housing, below the support for the particulate media. Advantageously, the opening of the liquid discharging means is disposed on the lower wall of the housing of the system according to the invention to prevent the filtered effluent from accumulating at the bottom of the housing. According to one embodiment of the invention, said opening may be connected to a wastewater discharge system, such as a siphon upstream of a main drainage device. Depending on the geometry, a lift pump may be used to discharge the filtered effluent.

[0054] The system according to the invention also includes means for connecting a particulate media fluidization regeneration device, comprising at least one opening provided in the upper part of the housing, above the particulate media. The particulate media fluidization regeneration device is intended to prevent clogging of the particulate media, as filtered microfibers can accumulate in the particulate media, potentially causing blockage. Generally, fluidization of the particulate media is achieved by upward passage of liquid or gas through the particulate media. Preferably, the particulate media fluidization regeneration device that can be connected to the system according to the invention is a gas fluidization regeneration device. Gas fluidization is understood as the fluidization of particles in the particulate media by gas. The upward flow of gas causes the particles in the particulate media to move, resulting in expansion of the particulate media in the free volume above the particulate media, with fibers entrained by the rising airflow. According to one embodiment of the invention, the system according to the invention can be connected to a particulate media regeneration device in the form of a gas suction device (such as a household or industrial vacuum cleaner) and / or a gas blowing device (such as an air compressor or overpressure system) via the connection means according to the invention. According to this embodiment, the gas used for fluidizing and regenerating the particulate media can enter the system through an opening in a liquid outflow device provided in the lower part of the housing.

[0055] The device for connecting the particulate media fluidized regeneration apparatus according to the system of the present invention includes at least one opening located above the particulate media, on the upper part of the housing. The opening allows the release of microfibers from the particulate media through fluidization. Preferably, the opening for connecting the particulate media fluidized regeneration apparatus is located on the upper wall of the housing of the system according to the present invention, preferably in the central portion of the upper wall (e.g., in a region centered on the centroid of the upper wall, with a radius corresponding to 30% of the minimum dimension of the upper wall). An opening located in the central portion of the upper wall of the housing allows for more uniform lateral regeneration of the particulate media compared to an off-center opening. As described in the following embodiments, the opening of the channel device for effluent percolation through the particulate media and the opening of the device for connecting the particulate media fluidized regeneration apparatus can be common, and their filtration or regeneration function can be controlled by a control means, such as a valve comprising at least a three-way valve. According to one embodiment of the present invention, the opening of the channel device for effluent percolation through the particulate media and the opening of the device for connecting the particulate media fluidized regeneration apparatus can be common, and their filtration or regeneration function can be controlled manually or automatically.

[0056] The apparatus for regeneration via fluidization of the particulate medium can increase the service life of the system according to the invention. Advantageously, the apparatus for fluidization regeneration of the particulate medium is used to remove the microfibers from the particulate medium when the accumulated microfiber volume is 0.1 to 10% of the porosity of the particulate medium, preferably 0.5 to 5%. Therefore, one hundred regeneration stages can be performed before replacing the particulate medium in the system according to the invention.

[0057] Advantageously, within the housing, a grid can be provided between the opening of the channel device for effluent percolation through the particulate media and the particulate media, the opening size of the grid being smaller than the particle size of the particulate media. The grid can retain particles of the particulate media within the housing during fluidized regeneration. Advantageously, the grid can also make the distribution of the effluent on the particulate media more uniform, thereby improving the filtration quality of the system according to the invention. Advantageously, a jet regulator can also be provided below the opening of the channel device for effluent percolation through the particulate media to allow the introduction of effluent for dispersion, thereby preventing excessively strong effluent jets from impacting the particulate media. Advantageously, a liquid distributor can be further placed between the opening of the channel device for effluent percolation through the particulate media and the particulate media. Generally, the liquid distributor ensures uniform liquid distribution. According to one embodiment of the invention, the liquid distributor can be a perforated liquid trapping plate. The distributor can ensure uniform liquid distribution across the cross-section of the particulate media.

[0058] Figure 1 A first embodiment of the system according to the invention is illustrated schematically by way of a non-limiting implementation. According to this design, the microfiber filtration system comprises a cylindrical housing 10 with a support 20 supporting a particulate medium 30 consisting of a particle bed, and a free volume 40 above it, allowing for the accumulation of effluent during filtration and / or the expansion of the fluidized particle bed 30 during regeneration. The system according to this embodiment includes an opening 100 located on the upper wall of the housing 10, which allows for the delivery of the effluent to be filtered from a drain pipe 100'. The system according to this embodiment also includes an opening 120 for connection via a pipe 120' to a particulate medium fluidization regeneration device (e.g., a gas suction device). The system also includes an opening 110 that allows the filtered effluent to be discharged at the bottom of the housing 10. The opening 110 is positioned below the particulate medium 30 and the particulate medium support 20, and can be connected via a pipe 110' to a wastewater discharge system (not shown), such as a siphon pipe upstream of a main drainage device.

[0059] Figure 2a Showing Figure 1 A variation of the implementation, identical in all respects to the first embodiment (and therefore common elements will not be described again), except that a grid 35 is provided between the opening 120 for connecting the fluidized regeneration device (not shown) and the particulate medium 30, the opening size of the grid 35 being smaller than the particle size of the particulate medium 30. The grid 35 can trap particles of the particulate medium 30 within the housing 10 during fluidized regeneration. Advantageously, the grid 35 can also allow the effluent arriving through the opening 100 to be more uniformly distributed on the particulate medium 30 (jet conditioning function), thereby improving the filtration quality of the system according to the invention.

[0060] Figure 2b Showing Figure 1 Another variant of the implementation method is identical to the first embodiment in all respects (therefore, common elements will not be described again), except that the shape of the outer casing 10 is cylindrical at the bottom, truncated conical in the middle, and cylindrical at the top, with the cross-section of the top being larger than that of the bottom. This special geometry of the outer casing 10 increases the free volume above the particulate medium, which, on the one hand, avoids the risk of backflow through the openings 100 and 120 at the top of the casing in the event of effluent accumulation above the particulate medium 30 (which may occur in the event of particulate medium blockage), and on the other hand, improves the regeneration capacity of the particulate medium by increasing the available volume for fluidized expansion of the particulate medium 30.

[0061] Therefore, generally speaking, the system and method according to the invention can filter microfibers contained in the effluent by trapping them in the pores of the particulate media through which the effluent can pass. This type of filtration, known in other fields as "depth filtration," is particularly suitable for capturing microfibers, whose elongated shape is advantageous for trapping at bends in the particle bed. It should be noted that some microfibers can also be trapped on the upper surface of the particulate media. The system according to the invention can also be connected to a particulate media fluidized regeneration device, thereby cleaning the filter according to the invention and having the possibility of collecting the microfibers trapped in the pores of the particulate media.

[0062] The particulate medium according to the invention comprises at least one particulate bed, hereinafter referred to as a "filter bed" or "filtration bed" in an equivalent manner. According to one embodiment of the invention, the particulate medium may comprise multiple stages of particulate beds, each supported by a support member that is at least permeable to the effluent (and thus generally permeable to gases, particularly those used for gas fluidization regeneration of the particulate medium). Therefore, in the system implemented according to the invention, the effluent can permeate from top to bottom through each stage of the bed.

[0063] The constituent materials of a particle bed can be defined by its composition, particle size, and density. Various particle types can be considered for particle beds, as described below.

[0064] According to one embodiment of the invention, the particles in the bed can be sand, crushed glass beads or original glass beads, particles based on natural or synthetic zeolites, alumina, or resin or plastic. These materials do indeed have the advantage of being readily available on the market, and they possess properties suitable for the target application (particularly in terms of density, as described below). According to an alternative, the particles in the bed can be composed of a material with modified surface properties to promote the retention of microfibers, either through physicochemical affinity with textile microfibers (particularly by altering the electrostatic properties of the particles) or by limiting the hydrophilicity of these particles (through hydrophobic treatment, such as coating particles like glass beads with a Teflon film), which facilitates drying before bed regeneration. According to another embodiment of the invention, a mixture of particles made from materials of different properties can be used in a single bed, or if the particle medium consists of multiple graded beds, particles made from materials of different properties can be used from one bed to another.

[0065] Generally, particle size affects the filtration and regeneration capacity of particulate media for microfibers by acting on the resistance to fluid flow. According to an advantageous embodiment of the invention, for at least 80 wt% of particles, the particle size can be between 0.1 mm and 2 cm, preferably, for at least 90 wt% of particles, the particle size can be between 0.3 mm and 2.5 mm. Additionally, the average equivalent diameter of the particles in the particulate media (defined by size distribution weight) can be between 0.3 mm and 1.35 mm, preferably between 0.4 mm and 0.8 mm. Advantageously, the proportion of particles with a diameter less than 0.1 mm can be less than 5 wt%. Advantageously, particles of different sizes can be used in a single bed, or when the particulate media consists of multiple graded beds, particles of different sizes can be used from one bed to another. Advantageously, in the case where the particulate media consists of multiple graded beds, these beds can consist of particles whose size decreases along the liquid outflow direction (i.e., downwards) so as to filter larger fibers first, followed by progressively smaller fibers. The described implementation is particularly suitable for situations requiring the retention of very small colloidal particles in the effluent. For example, these colloidal particles may be formed from pigments and additives found in textiles and detergent ingredients. The method for capturing these colloidal particles is particularly suitable for the last bed in the casing in the direction of effluent flow. This last bed in the direction of liquid outflow, which may be referred to as the finishing bed, may not be connected to the regeneration device and can be replaced periodically.

[0066] Generally, the particle density of the granular bed affects the fluidization of the particles during the regeneration process (the minimum velocity allowed for fluidization of the bed and the pressure drop across the bed). The particle density of the constituent materials of the aforementioned particles (e.g., sand, glass, zeolite) is typically between 1100 and 2800 kg / m³. 2 The bed is suitable for regeneration via methods such as gas suction, even at moderate suction flow rates (e.g., using a household vacuum cleaner). Advantageously, hollow materials, such as hollow glass or plastic beads, can be used, which have a lower particle density, thus allowing for bed regeneration at lower fluid flow rates.

[0067] Generally, the velocity of the effluent flowing through the granular bed affects both the fiber retention quality and the pressure drop of the effluent through the granular bed. Advantageously, the system according to the invention is sized such that the filtration velocity (the surface velocity of the effluent in the granular bed) is between 1 and 100 m / h, preferably between 5 and 50 m / h. Preferably, the system according to the invention is sized such that the pressure drop provided by the clean granular bed (i.e., before any filtration or after regeneration) is between 500 and 100,000 Pa, preferably between 1,000 and 10,000 Pa. The flow pressure drop of the effluent through the granular bed (during initial use or after regeneration) can be calculated using, for example, the relationships described in the document (S. Rhode, "Opération polyphasique engénie des procédés" (Ellipses edition, 2019)).

[0068] According to one embodiment of the invention, the appropriate effluent filtration rate and pressure drop can be determined by a dimensional measurement method known to experts, the dimensions of which can be determined at least based on the amount of effluent to be filtered in a given time, the discharge pressure of the textile processing equipment's drain pipe, and the position of the system according to the invention in the drain pipe section of the textile processing equipment (note the position of the filtration system of the invention relative to the drain outlet of the textile processing device, and relative to the wastewater discharge system connected to it during operation of the filtration system according to the invention).

[0069] Generally, the flow rate of the effluent to be filtered depends on the washing capacity of the textile processing equipment. For example, if the textile processing equipment includes multiple washing machines, the flow rate of the effluent to be filtered depends on the number of washing machines and the washing capacity of each washing machine (e.g., expressed in kilograms of laundry). According to an embodiment of the invention, for a household washing machine capable of washing 5 to 10 kg of laundry, the system according to the invention can be sized such that its filtration rate is between 1 and 25 l / min, preferably between 3 and 15 l / min. The filtration rate depends on the filter surface and the aforementioned filtration rate.

[0070] According to one embodiment of the invention, wherein a single particle bed is provided within the housing of the system, and for a washing machine washing 5 to 10 kg of laundry, the inner diameter of the housing can be between 5 and 50 cm, preferably between 10 and 30 cm, to achieve the optimal filtration speed defined above. Advantageously, the height of the particle bed can vary between 0.5 and 5 times the equivalent diameter of the particle bed flow area, preferably between 0.7 and 2 times the equivalent diameter of the particle bed flow area, which allows time for the microfibers to settle in the pores of the bed.

[0071] According to another embodiment of the invention, the housing is parallelepiped in shape, and the filtration system can be placed at the rear or side of the washing machine. The parallelepiped shape is particularly suitable for placing the system according to the invention outside the washing machine, as it can therefore be more easily installed in the available space around the washing machine. The filtration system can preferably be placed on the floor, or it can be attached to a wall or a component of the washing machine. Advantageously, if the system according to the invention is located at the rear of the washing machine, preferably, the housing dimensions are chosen not to exceed the height and width of the washing machine, and if the system according to the invention is located on the side of the washing machine, the housing dimensions do not exceed the height and depth of the washing machine. Preferably, in the case of washing 5-10 kg of laundry, the height of the housing can be less than 85 cm, its width preferably less than 60 cm, and its thickness preferably less than 20 cm, more preferably less than 15 cm, and even more preferably less than 10 cm.

[0072] Very preferably, the system according to the invention can be connected to a particle bed regeneration device in the form of a gas suction device and / or a gas blowing device via the connection device according to the invention.

[0073] The gas extraction device can achieve gas extraction through at least one opening located in the upper part of the housing, above the particulate media, at the level of the free volume above the particle bed, to expel particles accumulated on and within the filter bed. Under the action of the extraction rate, an upward convective gas movement is generated in the particle bed. The particles in the filter bed are set to move and fluidize, without being entrained by the airflow. Fibers smaller than the particles constituting the filter bed are entrained in the upward airflow. Preferably, the gas in the gas extraction device is air, which allows the use of conventional extraction devices (such as household or industrial vacuum cleaners) without the need for a gas storage device or a gas intake device other than a simple ventilation duct. Advantageously, the gas extraction device includes, or can be accomplished by, a particle separation system located downstream of the gas extraction device, such as a cyclone chamber or membrane filter, for collecting microfiber particles. It should be noted that household vacuum cleaners generally include such a particle separation system. The space above the particulate media, serving as an accumulation zone during the filtration stage, allows for the accommodation of bed expansion related to its fluidization during the bed regeneration stage. Following the bed regeneration stage, the suction flow is stopped, and the particles settle, thus forming a new filter bed free of fibers deposited in the previous filtration stage. Advantageously, the fibers collected during the regeneration stage can be used as recycled material or treated as harmless waste in a suitable collection system.

[0074] Generally speaking, in the regeneration process of a particle bed, the velocity of the rising gas determines the agitation of the particle medium. As is well known to those skilled in the art, in order to move the particle bed, the gas needs to rise through the particle bed at a velocity greater than what is known as the "minimum fluidization velocity." This velocity can be calculated using correlations known to those skilled in the art (e.g., in the document (Wen CH & Yu YH, Chem. Eng. Prog. Symp. Series, 82, 100-111 (1966)), and its value depends on the characteristics of the particle medium (particle size, density). Preferably, during regeneration, the rising air motion fluidizes the particle bed, and its velocity through the bed is preferably 2 to 20 times the minimum fluidization velocity value to promote agitation of the particles in the bed, thereby causing the collected microfibers to leave the bed and rise into the air. More preferably, the velocity of the rising air through the bed can be 3 to 10 times the minimum fluidization velocity. In the case of washing 5 to 10 kg of clothes in a household washing machine, this range of rising gas velocities can ensure fluidization without the need for any specific suction means. In other words, this range of rising gas velocities is generally compatible with the characteristics of most household commercial vacuum cleaners.

[0075] Generally, the suction rate through the filter media depends on the washing capacity of the textile processing equipment. For example, if the textile processing equipment includes several washing machines, the suction rate through the filter media depends on the number of washing machines and the washing capacity of each machine (e.g., expressed in kilograms of laundry). If the required effluent volume to be filtered increases, the flow area of ​​the filter bed will increase. The suction rate then needs to be adjusted to fluidize the media. The height of the fluidized bed will produce a pressure drop corresponding to the weight of the bed, which must also be adapted to the characteristics of the suction regeneration device.

[0076] For simple household washing machines with a capacity of 5 to 10 kg, the system's dimensions allow for a suction rate approaching 10 to 100 l / s, preferably 20 to 40 l / s, enabling a suction vacuum of 5 to 50 kPa, preferably 20 to 40 kPa. These characteristics are compatible with most commercial vacuum cleaners available for home use. When the system according to the invention is placed downstream of an industrial laundry or a group of washing machines, a specific suction system characterized by higher suction rates and speeds may be preferred.

[0077] According to one embodiment of the invention, in which a gas other than air is used in the regeneration apparatus for fluidizing particulate media by gas suction, the device connected to the particulate media fluidization regeneration apparatus may further include an additional opening located in the lower part of the housing, below the particulate media support, which can be connected to a gas delivery device for regeneration.

[0078] According to one embodiment of the invention, where the gas suction device is used for the regeneration of particulate media, the gas used is air, and the connection between the liquid discharge device and the wastewater discharge device outside the system according to the invention is completely sealed, the means for connecting the gas suction device may be included in the lower part of the housing, below the particulate media support, providing an additional opening. This additional opening may be connected to a vent. When the connection between the liquid discharge device and the wastewater discharge system outside the system according to the invention is not sealed, for example, if the connection is achieved through an open siphon, then the additional opening is not necessary. In fact, in this case, suction can be performed directly through the opening of the liquid discharge device without the need for a vent. Advantageously, the microfiber filtration system may further include a gas distributor located between the particulate media and the opening of the gas suction device that allows gas delivery (i.e., the aforementioned additional opening, or the opening of the liquid discharge device). The gas distributor provides a uniform distribution of gas. According to one embodiment of the invention, the gas distributor may be a perforated plate. Advantageously, the orifice size of the perforated plate is such that the pressure drop generated when gas flows through the orifice results in a uniform gas distribution at the distributor outlet. According to another variation of the invention, the system according to the invention can be connected via a connection device according to the invention to a device for regenerating a particle bed in the form of a gas blowing device (e.g., an air overpressure or compression device). According to this design, the device for connecting the particle media fluidized regeneration device may further include an additional opening located in the lower part of the housing, below the particle media support, which can be connected to the gas blowing device. Gas is thus introduced into the lower part of the housing, below the particle media, at a pressure higher than that of the filtration system, thereby generating an upward airflow through the particle media. This causes the moving bed particles to release microfibers trapped in the particle media, which can be discharged through the opening of the device, which is connected to the particle media fluidized regeneration device provided in the upper part of the housing as described above.

[0079] Figure 2c Showing Figure 1A variation of the implementation, identical in all respects to the first embodiment (and therefore common elements will not be described again), wherein the means for connecting the particulate media fluidized regeneration apparatus further includes an additional opening 130 provided in the lower part of the housing, below the support 20 of the particulate media 30, which can be connected via a conduit 130' to a gas inlet and / or gas delivery device (not shown). In the case of a gas inlet device, an air compressor (not shown) located upstream of the conduit 130' can input air at a pressure higher than that of the particulate media 30, and the air flowing through the particulate media 30 can exit through the opening 120. The conduit 130' can alternatively serve as an intake pipe, for example, in the case of a gas suction device where the regeneration gas is air, it can be a vent pipe. The additional opening 130 or the conduit 130' preferably includes a check valve (not shown).

[0080] Advantageously, the system according to the invention may further include means for accelerating filtration by suctioning the effluent after filtration (i.e., after passing through the particulate media), said means being positioned downstream of the particulate media. The means for generating suction on the effluent passing through the particulate media may include a first conduit connected to an additional opening on a housing located below the particulate media, the first conduit being connected to a second conduit through which water can flow during filtration, the second conduit including a smaller diameter section to generate suction through a Venturi effect in the first conduit. For example, the second conduit through which water can flow may be the water inlet pipe of a washing machine. Indeed, in the case of a washing machine equipped with the system according to the invention, the drainage phase is shorter than the filtration phase of the effluent passing through the particulate media. Therefore, when the washing machine enters the next cycle (a textile washing cycle includes several wash / rinse cycles), at the end of a drainage cycle, the washing machine refills with water while the filtration phase is still in progress: the filtration can then be accelerated by utilizing the Venturi suction effect generated during the water inlet phase of the washing machine. The filtration acceleration device may also include a vacuum cleaner, a vacuum generator, or a vacuum pump positioned along an additional conduit located downstream of the particulate media.

[0081] Advantageously, the device for discharging effluent from the system according to the invention further includes an external circuit connected to the housing for bypassing the particulate media when effluent accumulates in the free volume of the housing above the particulate media. In other words, according to the design, a portion of the effluent that may accumulate above the particulate media (in cases where the effluent flow rate exceeds the filtration rate of the particulate media and / or the particulate media becomes clogged) is discharged through the external circuit to prevent backflow of the effluent through the opening at the top of the housing. Advantageously, the connection of the external circuit includes an opening above the particulate media through which a portion of the effluent (above the level of the opening) can be discharged, and an opening below the particulate media through which this portion of the effluent can be discharged from the system according to the invention through an opening at the bottom of the housing, below the particulate media. Advantageously, as described below, the external short circuit can also be equipped with a two-way valve or a check valve to prevent backflow of gas in the upward vertical direction during the particulate media regeneration phase. Preferably, the opening of the external short-loop conduit located above the particulate medium can be advantageously located above any device that allows for alteration of the liquid outflow distribution (such as a grid, jet regulator, or more generally, a liquid distributor).

[0082] Furthermore, the effluent discharge device of the system according to the invention also includes a conduit that passes through at least the particulate medium to allow effluent to accumulate in the free volume of the housing above the particulate medium. In other words, according to the design, a portion of the effluent that may accumulate above the particulate medium (in the event that the effluent flow rate is too high relative to the filtration rate of the particulate medium and / or the particulate medium is clogged) enters through an opening in the conduit above the particulate medium and exits through an opening in the conduit below the particulate medium. The conduit, as an internal short loop, prevents effluent from flowing back through the opening in the upper part of the housing. Preferably, the conduit according to the design is preferably provided with a flow guide at its upper part to prevent effluent entering through the upper part of the housing from directly entering the conduit. Advantageously, as described below, the internal short loop pipe may also be configured with a check valve to prevent gas in the short loop from flowing back in the upward vertical direction during the particulate medium regeneration phase.

[0083] According to one embodiment, the aforementioned internal and / or external short loops may include a liquid detector, preferably connected to an alarm. The detector can detect the presence of water circulation in the short loop, which can be an indicator that a particulate media regeneration phase is preferably performed, since at least a portion of the effluent is no longer filtered by the system of the present invention. For example, the liquid detector may consist of two metal branches spaced a few millimeters apart, located within the short loop conduit and supplied with electricity (e.g., via a battery, accumulator, or connection to the power grid). When water flows between the two branches, an electric current is established, which can trigger an alarm, such as a visual and / or audible one. Advantageously, the visual signal can be maintained for an extended period, even after water has passed through the short loop conduit, to alert the user if the user is not present when the alarm is triggered.

[0084] Very preferably, the system according to the invention further includes a chamber located upstream of the housing, the chamber being connected to the housing via a channel device for effluent permeation through the particulate media, the chamber serving as an effluent reservoir during drainage. Depending on operating conditions or blockage, the reservoir can delay filtration by reducing the filtration rate of the effluent through the particulate media. The effluent reservoir's location upstream of the housing in the effluent path allows the system according to the invention to potentially use a smaller housing, and the free volume of the housing above the particulate media requires a basic size to fluidize the particulate media during the regeneration phase. Furthermore, the effluent reservoir chamber can have any shape and can be located anywhere on the drain pipe of the textile processing equipment; therefore, as long as the available space is substantially above the housing and allows liquid flow under gravity, the chamber can be located within any available space of the textile processing equipment.

[0085] Figure 2d Showing Figure 1 A variant of the embodiment, identical in all respects to the first embodiment (and therefore common elements will not be described again), except for an external short circuit 140, which takes the form of a pipe outside the housing 10 and is part of the effluent discharge device of the system according to the invention. According to this variant, the external short circuit 140 connects the upper part of the free volume 40 of the housing 10 to the lower part of the housing 10 located below the support 20 of the particulate medium 30. This prevents backflow of effluent through the two openings 100, 120 in the upper part of the housing. In this case, a two-way valve 53 is provided on the pipe 140 to prevent backflow of gas in the upward vertical direction during the particulate medium regeneration stage. The two-way valve 53 can be replaced by a check valve (not shown).

[0086] Figure 2e Showing Figure 1A variant of the embodiment, identical in all respects to the first embodiment (and therefore common elements will not be described again), except for the internal short loop 140 within the housing, which takes the form of an internal conduit belonging to the effluent discharge device of the system according to the invention. According to this variant, the internal short loop 140 comprises a conduit directly connecting the upper part of the free volume 40 of the housing 10 to the lower part of the housing located below the support 20 of the particulate medium 30. This prevents backflow of effluent through the two openings 100, 120 in the upper part of the housing. In this variant, a flow guide 56 is provided above the internal loop to prevent effluent entering through the opening 100 from flowing directly into the internal short loop 140. Additionally, according to this variant, the internal short loop 140 is equipped with a check valve 57 to prevent gas from flowing back in the upward vertical direction in the conduit 140 during the particulate medium regeneration phase.

[0087] Figure 2f Showing Figure 1 A variant of the implementation, identical in all respects to the first embodiment (and therefore common elements will not be described again), except that an additional chamber 11 is provided upstream of the housing 10, along the opening 100 of the drain pipe 100' leading to the channel device for percolation of the effluent through the particulate medium 30. This chamber 11, depending on operating conditions or blockage, helps to delay the filtration process by reducing the filtration rate of the effluent through the particulate medium 30. If the flow rate of the filter bed is lower than the drain flow rate, this prevents backflow of the effluent through the two openings 100, 120 located in the upper part of the housing 10. The flow between the chamber 11 and the housing 10 occurs substantially under gravity, with the chamber 11 located substantially above the housing 10.

[0088] According to one embodiment, the system according to the invention further includes means for controlling: a channel device for effluent percolation through the particulate media and / or the effluent discharge device and / or means for connecting the particulate media fluidized regeneration device. The control means may include a two-way valve, a three-way valve, a rotary six-way valve, and / or a check valve. The control means can control two phases of the method according to the invention: 1) in the filtration phase, only the effluent can enter and exit the housing, and only through the channel device for effluent percolation through the particulate media and the effluent discharge device; 2) in the regeneration phase, only the gas from the particulate media fluidized regeneration device can circulate within the housing. Of course, combinations of these control means are possible. Figures 3 to 7b The document introduces various unrestricted and non-exhaustive configurations.

[0089] Figure 3 By way of non-limiting examples, one embodiment of the invention is illustrated, including an external short circuit 140 (e.g., Figure 2dThe above) and additional devices for connecting the regeneration via the fluidization of the particulate media 130, 130' (e.g. Figure 2c The device, as described above, includes two-way valves 51, 52, 53, 54, and 55 provided on each of the pipes 100', 110', 120', and 130' respectively connected to the openings 100, 110, 120, and 130 of the housing and on an external short circuit 140. Valves 51, 52, 54, and 55 allow the openings 100, 110, 120, and 130 to be opened or closed respectively during the filtration or regeneration phase. During the regeneration phase, gas flow through the external short circuit 140 is prevented by valve 53 located on the short circuit. The two-way valve 53 can preferably be replaced by a check valve (not shown).

[0090] Figure 4 One embodiment of the invention is illustrated by way of non-limiting examples, including an internal short circuit 140 (e.g. Figure 2e (as described above) and additional connections are made via the particulate media 130, 130' (e.g.) Figure 2c The apparatus is a device for regenerating the fluidized medium 30. Each pipe 100', 110', 120', 130' connected to the openings 100, 110, 120, 130' of the housing is equipped with a two-way valve 51, 52, 54, 55, and a check valve 57 is provided at the bottom of the internal short-loop pipe 140. Valves 51, 52, 54, 55 allow the openings 100, 110, 120, 130 to be opened or closed, respectively, during the filtration or regeneration stage. During the regeneration stage of the particulate medium 30, the check valve 57 prevents gas from flowing back through the pipe 140 in the upward vertical direction.

[0091] Figure 5 One embodiment of the invention is illustrated by way of a non-limiting example, which includes additional means for connection to regeneration via fluidization of the particulate media 130, 130' (e.g. Figure 2cThe apparatus described above, wherein the openings 100 and 120 for connecting the particulate media fluidized regeneration device and the channel device for effluent percolation through the particulate media 30 are common, and wherein a three-way valve 58 is provided at the junction of pipes 100', 120', 120" and 130" to control the fluid through these pipes 100', 120', 120" and 130" in stages according to the method of the invention, i.e., only effluent is allowed to pass through elements 100, 100' and 100" in the filtration stage, and only gas is allowed to pass through elements 120, 120' and 120" in the regeneration stage. According to the non-limiting embodiment described above, check valves 59 and 60 are also provided on each pipe 110' and 130', which are respectively connected to the openings 110 and 130 in the lower part of the housing 10, so that effluent is discharged only through opening 110 and gas is drawn in or blown in only through opening 130.

[0092] Figure 6 The following non-limiting embodiments are illustrated schematically. Figure 5 In one variant, the openings 110 and 130 of the connection device for the particulate media fluidized regeneration device and the effluent discharge device are also common, and a three-way valve 61 is provided at the junction of pipes 110', 130', 110", and 130" to control the fluid through these pipes 110', 130', 110", and 130" in the procedural stages of the method according to the invention. Therefore, in this variant, the use of three-way valves 58 and 61 allows the system according to the invention to be used in either the filtration stage or the regeneration stage. More precisely, in the filtration stage, opening 100 is opened and opening 120 is closed via valve 58, and opening 110 is opened and opening 130 is closed via valve 61. In the regeneration stage, opening 120 is opened and opening 100 is closed via valve 58, and opening 130 is opened and opening 110 is closed via valve 61. Therefore, it is only possible for the effluent to pass through during the filtration stage, and only in elements 100, 100', 100", 110, 110', 110"; and it is only possible for the gas to pass through during the regeneration stage, and only in elements 120, 120', 120", 130, 130', 130".

[0093] Figure 7a and 7bBy way of a non-limiting example, one embodiment of the invention is illustrated, wherein the means for controlling the connection between the channel device for effluent percolation through the particulate media, the effluent discharge device, and the fluidized bed regeneration device is controlled by a rotary six-way valve 62. In this embodiment, the openings 100 and 120 of the channel device for effluent percolation through the particulate media and the connection device of the particulate media fluidized bed regeneration device are common, as are the openings 110 and 130 of the connection device of the effluent discharge device and the particulate media fluidized bed regeneration device. Figure 7a The positions of components 62a, 62b, 62c, and 62d of the six-way valve 62 are indicated by dashed lines. During the filtration stage, these components are only connected to openings 100 and 110. Figure 7b The positions of components 62a, 62b, 62c and 62d of the six-way valve 62 are indicated by dashed lines. During the regeneration phase, only openings 130 and 120 are connected.

[0094] Advantageously, the system according to the invention may further include a settling chamber and / or a hydrocyclone separation chamber (such as a hydrocyclone), said chamber being disposed upstream of the housing and connected to the housing via means for percolating the effluent through the particulate medium. The settling chamber allows larger fibers to settle under gravity. The hydrocyclone separation chamber (such as a hydrocyclone) separates larger fibers by inducing eddies and a centrifugal force field that promotes separation. Located upstream of the housing relative to the effluent flow, the separation chamber can capture larger fibers and limit excessively rapid clogging of the particulate medium, thus allowing for more efficient capture of the majority of smaller fibers.

[0095] Preferably, the system according to the invention further includes means for injecting at least one flocculant into the effluent, said means being configured to inject the flocculant into the effluent before it enters the particulate medium. The means for injecting at least one flocculant into the effluent may be located upstream of the housing and connected to the housing via a channel means for the effluent to permeate through the particulate medium, or configured to inject into the free volume above the particulate medium through an opening in the upper part of the housing. When the flocculant is in liquid form, the means for injecting at least one flocculant may include a tank containing said at least one flocculant and means for controlling the flocculant flow rate. For example, when the flocculant is in liquid or solid form, it may also be mixed with liquids in textile processing equipment, such as with detergent in a washing machine. The flocculant can promote the aggregation of smaller fibers, which facilitates their separation from the effluent as they pass through the particulate medium. For example, flocculants in the form of polyvalent cationic mineral salts, such as aluminum sulfate or ferric chloride, activated silica, or natural (starch, alginic acid) or synthetic (high molecular weight polymers, such as polyacrylamide or polyethyleneamine) organic polyelectrolytes can be used. The flocculant is preferably injected at a low proportion, generally between 1 and 20 ppm in the effluent, and a device that promotes mixing of the flocculant in the effluent is preferred. Flocculation is particularly interesting when the microfiber size is one micrometer or less.

[0096] Figure 8 An embodiment of the system according to the present invention is described, the system comprising a particulate medium consisting of three graded particle beds 30a, 30b, and 30c arranged on three supports 20a, 20b, and 20c, with free volumes 40a, 40b, and 40c above each bed 30a, 30b, and 30c, respectively. An opening 120 provided in the upper wall of the housing 10 is intended for connection to a particulate medium fluidized regeneration device (not shown).

[0097] The present invention further relates to a method for containing microfibers in a filtered effluent, the method being advantageously implemented by a system for containing microfibers in a filtered effluent according to any one or a combination of the above embodiments.

[0098] The method according to the present invention comprises at least the following steps:

[0099] A) A stage of filtering at least one microfiber contained in the effluent, the filtration stage comprising passing the effluent through at least the particulate medium using means for passing the effluent through at least the particulate medium, and discharging the filtered effluent using means for discharging the effluent.

[0100] B) The fluidization regeneration stage of the particulate media is performed by connecting a device for connecting the particulate media fluidization regeneration device to the particulate media fluidization regeneration device, such as a gas intake device or a gas blowing device.

[0101] Advantageously, step A) is repeated 20 to 150 times, preferably about 100 times, before step B). In fact, periodic regeneration of the filter media is important to prevent clogging, but it is not necessary to systematically perform a regeneration phase after each filtration stage, depending on the microfiber load in the effluent. For example, the trigger frequency of the regeneration phase can be estimated by the microfiber concentration in the effluent after each wash, which can be used to estimate the rate at which the filter bed pores become clogged due to microfiber accumulation. This embodiment can significantly save energy by avoiding systematic regeneration phases.

[0102] Preferably, after multiple filtration stages, a particulate media fluidized regeneration stage is performed when a slowdown in the percolation rate of the effluent is detected. According to one embodiment, the particulate media regeneration stage may begin as follows: for each filtration stage, the change in the effluent level in the free volume above the particulate media over time is measured; the measured value is compared with a reference value for the percolation rate obtained, for example, when the particulate media does not contain microfibers; and when the measured value is at least 100% lower than the reference value, or preferably at least 50% lower, the particulate media fluidized regeneration stage is performed after the ongoing filtration stage.

[0103] Preferably, the fluidized regeneration stage of the particulate media is initiated within a predetermined time after the completion of the last filtration stage, at least allowing the discharge of effluent and preferably also allowing the drying of the particulate media to remove all moisture. The predetermined time can be between 3 and 7 hours, preferably 5 hours. According to one embodiment of the invention, to promote drying, natural or forced gas convection through the particulate media can also be established by keeping the openings of the effluent discharge device and the device connected to the particulate media fluidized regeneration device open. When using hydrophobic particles and / or manufacturing the filter with hydrophobic materials, the predetermined time can be advantageously reduced.

[0104] Advantageously, the method according to the invention may include, prior to step B), a particulate media discharge stage using a gas suction device connected to the system according to the invention, thereby generating a downward airflow through the particulate media. In other words, the gas suction device is connected to the system according to the invention at an opening located below the particulate media, preferably above the lower wall of the housing. According to an embodiment of the invention, the gas suction device may be connected to an opening of the effluent discharge device, or, if applicable, to an additional opening for connecting the particulate media fluidized regeneration device. Gas suction through the opening located at the lower part of the housing forces downward gas convection through the particulate media. This forced gas convection carries away most of the residual liquid present in the gaps between the particulate media, thereby promoting its gravity flow and reducing the residual moisture of the bed. Under these conditions, with the aid of gas circulation, it is possible to reduce the liquid volume fraction in the bed to less than 10%, or even completely dry the bed if the time required for this step is long enough. Therefore, the gas circulation facilitates the gravity flow of the effluent adhering to the particulate media prior to regeneration of the particulate media. Preferably, the opening connecting to the gas suction device is located at a horizontal plane above the lower wall of the housing, and it includes a guide device for preventing discharged effluent from entering the gas suction device. Advantageously, the system according to the invention may include a device for collecting discharged effluent (such as a water trap) located upstream of the opening connected to the gas suction device to avoid excessive liquid entrainment into the gas suction device, which could affect the normal operation of the gas suction device.

[0105] Advantageously, the method according to the invention may include, prior to step B), preferably after the aforementioned drainage stage, a drying stage of the particulate medium by increasing its temperature. This drying stage provides accelerated drying compared to the drainage stage, which takes a sufficiently long time to facilitate drying of the particulate medium. According to one embodiment of the invention, the drying stage of the particulate medium can be performed by connecting a gas blowing device to the system according to the invention to generate an upward or downward airflow through the particulate medium and to heat it before allowing it to enter the housing. For example, a heat source (e.g., a heating resistor, a heat exchanger) located between the gas blowing device and the opening to which the gas blowing device is connected can be used to heat the gas. According to this embodiment, the gas blowing device can be connected to the system of the invention at the opening height of the particulate medium fluidization regeneration device provided above the particulate medium, or at an additional opening below the aforementioned particulate medium support, or at any other opening. Preferably, the gas used is a gas with low water vapor content. According to one design of an embodiment of the invention, the gas blowing device may consist of a blower. According to another embodiment of the invention, the drying stage of the particulate medium can be carried out by increasing the temperature of the particulate medium through percolation of hot liquid, or by heating the walls of the particulate medium. For example, heating the walls of the particulate medium can be achieved by placing heating resistors in contact with the walls of the particulate medium, or even placing them directly on the walls of the particulate medium. Advantageously, the particulate medium is heated to a temperature of 30°C to 90°C, preferably at least 50°C to 70°C. This temperature can cause more than 95% of the residual moisture present in the particulate medium at the start of the drying process to be expelled within 30 minutes, or even within 10 minutes.

[0106] Figure 9 Showing Figure 1 One variation of the implementation (and therefore common elements are no longer described) is configured to perform a particulate media drainage stage prior to the regeneration of the particulate media, followed by a particulate media drying stage. For this configuration, an additional opening 130 is provided in the housing, its height exceeding that of the lower wall of the housing, intended to connect to a gas suction device (not shown) via a conduit 130'. Furthermore, above the opening 130 is a flow guide 130', which allows liquid to flow through the particulate media 30 by gravity, diverting around the opening 130, while simultaneously allowing gas to pass through, which is much less affected by gravity. The conduit 110', which allows connection of the opening 110 to a wastewater discharge system (not shown), is equipped with a valve 111, which can discharge (open the valve) the effluent accumulated before and during the drainage stage.

[0107] More specifically, during the particulate media drainage stage, the system is connected to a gas extraction device via opening 130 and pipe 130', and air is drawn in from the ambient medium through opening 120. During extraction, the airflow passes through the bed at a velocity preferably between 0.1 and 5 m / s, more preferably between 0.3 and 3 m / s. In the subsequent filtration stage, the gas promotes the flow of liquid accumulated in the particulate media. Therefore, residual liquid flows through the particulate media 30 and the support 20, and accumulates around pipe 130' below opening 130 in the space of system 10 below support 20. After drainage, gas extraction can continue for several minutes and then be stopped. By opening valve 111, the liquid accumulated around pipe 130' is discharged through pipe 110.

[0108] The drained particulate media is dried before regeneration. In this configuration, a gas extraction device can remain connected to opening 130, while a blower (not shown) can be connected to opening 120 via conduit 120'. Ambient air heated to approximately 50°C then enters the system through opening 120, flows through the filter media, releases its heat, and gradually fills with moisture generated by water evaporation controlled by local thermodynamic equilibrium conditions.

[0109] Once the drying stage is complete, regeneration of the particulate media is no longer carried out under conditions of excessively high humidity that could interfere with particulate fluidization. Subsequently, a gas extraction device is connected to opening 120, and the gas used to fluidize the particulate media flows in through opening 110.

[0110] According to one embodiment of the invention, the filtration and / or regeneration stages are controlled by the control device of the aforementioned microfiber filtration system, for example, by the aforementioned two-way valve, three-way valve, rotary six-way valve, and / or check valve, particularly... Figures 3 to 7b In the implementation method.

[0111] Advantageously, the method according to the invention includes at least one preliminary (i.e., prior to step A) step, namely, pretreatment of the effluent before it reaches the particulate medium.

[0112] According to one embodiment of the invention, the preliminary effluent pretreatment step may include a sub-step of injecting at least one flocculant into the effluent, for example using the flocculant injection device described above. The flocculant can promote the aggregation of smaller fibers, which facilitates their separation from the effluent as they pass through particulate media. For example, flocculants in the form of polyvalent cationic mineral salts, such as aluminum sulfate or ferric chloride, activated silica, or natural (starch, alginic acid) or synthetic (high molecular weight polymers, such as polyacrylamide or polyethyleneamine) organic polyelectrolytes can be used. The flocculant injection is preferably carried out at a low proportion, generally between 1 and 20 ppm of the effluent, and preferably using a device that promotes the mixing of the flocculant in the effluent. Flocculation is particularly interesting when the microfiber size is one micrometer or smaller. The flocculant can also be injected simultaneously with detergents used for washing textiles, and can be used in combination with detergents.

[0113] Alternatively or cumulatively, the preliminary steps of pretreating the effluent may include a sub-step of effluent sedimentation, for example, via a sedimentation chamber located upstream of the housing of the system according to the invention as described above. The sedimentation chamber allows larger fibers to settle under gravity. This preliminary sedimentation sub-step can capture larger fibers and limit excessively rapid clogging of the particulate media, subsequently allowing for more efficient capture of most smaller fibers.

[0114] Alternatively or cumulatively, the preliminary step of pretreating the effluent may include a sub-step of feeding the effluent into a cyclone separation chamber (such as a hydrocyclone) upstream of the housing of the system according to the invention. The cyclone separation chamber (such as a hydrocyclone) can separate larger fibers by inducing eddies and a centrifugal force field that promotes separation. This preliminary sub-step can capture larger fibers and limit excessively rapid clogging of the particulate media, thus allowing for more efficient capture of the majority of smaller fibers.

[0115] Advantageously, the initial step of pretreating the effluent may include a sub-step of injecting at least one flocculant into the effluent, followed by a sedimentation sub-step and / or a cyclone separation sub-step. The flocculant promotes the aggregation of smaller fibers, thereby improving the efficiency of the sedimentation and / or cyclone separation sub-steps, ensuring that there are no larger fibers and / or fiber agglomerates before the effluent passes through the particulate medium.

[0116] Advantageously, the method according to the invention also includes at least one step following the regeneration step, comprising collecting the microfibers from the regeneration stage, for example by means of a cyclone chamber or filter (e.g., a membrane filter) placed downstream of the aforementioned particulate media fluidized regeneration apparatus.

[0117] Therefore, the system and method according to the invention can filter microfibers from an effluent produced by washing, rinsing, and / or dehydration of textile processing equipment, with a capture efficiency of at least 80% for microfibers larger than 50 micrometers. The system and method according to the invention require no consumables and can be used for extended periods thanks to the regeneration potential of the particulate media in which microfibers may accumulate over time.

[0118] The present invention also relates to a textile washing apparatus, such as a washing machine, comprising at least one system according to any of the above embodiments for filtering microfibers contained in the effluent.

[0119] It goes without saying that the present invention is not limited to the embodiments of the systems and methods described and illustrated by way of example above; rather, it includes all variant embodiments and all combinations of these embodiments in order to combine their effects. For example, Figures 2a to 2f The implementation methods can be combined. These implementation methods can also be combined with... Figures 3 to 6 , and / or Figures 7a to 7b and / or Figure 8 The implementation methods can be combined. These implementation methods can also be combined with... Figure 9 The combination of implementation methods.

[0120] Example

[0121] The following application examples relate to the application of the microfiber filtration system and method according to the present invention in a single washing machine.

[0122] More specifically, the washing machine in this embodiment has a washing capacity of 5 kg of clothes and uses a maximum of 50 liters of water per wash. The wastewater discharge cycle for different program stages varies depending on the user's selection, but the washing machine is characterized by a maximum discharge volume of 15 liters during the washing stage, with the liquid drained within 3 minutes. The shortest time between two washing machine drainage cycles is approximately 15 minutes. The average fiber content of the wastewater is close to 0.02 g / L, equivalent to an average fiber release rate of 0.02% (relative to the weight of washed clothes). For 5 kg of washed clothes, the average amount of fiber collected by the filter per wash is 1 g.

[0123] The washing machine drains liquid through a drain point located at the bottom of the machine, 5 cm above the ground. There is a connection point to the main drainage system 15 cm above the drain point (therefore 40 cm above the ground where the washing machine is located).

[0124] In the application embodiment, according to Figure 5 In the design described herein, the filtration system is directly integrated into the washing machine. Therefore, the reference numerals mentioned below are consistent with... Figure 5The reference numerals in the accompanying drawings correspond to each other. In the application embodiment, the housing 10 containing the particulate medium 30 is cylindrical, with an inner diameter of 25 cm and a height of 60 cm. The height of the particulate medium 30 within the housing 10 is 25 cm. Above it is a free volume 40 with a height of 30 cm, which can hold 15 liters of effluent. The particulate medium is placed on a grid-like support 20 with a grid size of 0.15 mm. Below the grid, there is a 50 mm space for collecting liquid below the filter bed. The particulate medium 30 consists of sand with an average diameter of 0.5 mm, and 90% of the sand particles are between 0.3 and 0.7 mm in size. The average density of the sand particles is estimated to be 2550 kg / m³. 3 The porosity (interstitial space) of particulate medium 30 is estimated to be 41% of the regenerated particle volume.

[0125] A short loop pipe with an inner diameter of 10mm and an outer diameter of 12mm passes through the bed (e.g. Figure 4 (as shown), and equipped with a check valve.

[0126] According to the application embodiment, the filtration system is connected to the washing machine via a hose 100', which connects the drain pipe 100" to a three-way valve 58. The three-way valve 58 is located at a height of 105cm above the washing machine's drain outlet, i.e., 110cm above the ground. Therefore, the opening 110 is positioned above the washing machine's drain outlet, allowing the opening 110 to be connected to a regular wastewater discharge system via a siphon tube, and the filtered rinsing liquid to be discharged under gravity.

[0127] Initially, the three-way valve 58 is in the position where the effluent is filtered; in other words, opening 100 is open and opening 120 is closed. When the particulate media 30 is clean and freshly regenerated, by creating a pressure drop below 2000 Pa, corresponding to a static water height 20 cm lower than the height of the free volume 40, the bed characteristics enable a filtration rate of 6 L / min. Therefore, filtration through the bed percolation can be completed in less than 4 minutes. When the particulate media 30 becomes clogged after accumulating approximately 100 g of microfibers, the pressure drop doubles, equivalent to approximately 4000 Pa, i.e., a static water height of 40 cm, still lower than the height of the free volume 40. These characteristics ensure effective filtration of the effluent in approximately one hundred washes.

[0128] After approximately one hundred washes, the three-way valve 58 is actuated to regenerate the filter media. After the final wash, opening 100 is closed and opening 120 is opened. After waiting 5 hours for the particulate media 30 to drain and dry, opening 120 is connected to a commercial vacuum cleaner equipped with disposable filter bags, creating an upward convection airflow in the particulate media 30. Air enters through opening 130 equipped with check valve 59, which opens, and opening 110 is automatically closed by check valve 60. The vacuum cleaner allows a suction rate of 30 l / s and a suction power of 40 kPa. The fluidization velocity of the particles is 19.5 cm / s. Therefore, a flow rate of at least 10 l / s is required to fluidize the bed. Thus, using a vacuum cleaner with a suction rate of 30 l / s can fluidize the bed at a rate equivalent to three times the minimum fluidization velocity. The suction power required to compensate for the pressure drop of the particulate media in the fluidized state is approximately 4000 Pa, which is much less than the suction power of the vacuum cleaner. Therefore, the fluidized bed can be well fluidized, allowing microfibers to be discharged into the filter bag. After regeneration, suction stops, and sand particles settle to form the filter media again. Driving the three-way valve 58 returns to the filtration stage, opening opening 100 and closing opening 120.

[0129] The microfiber filtration system and method described herein can remove 80% to 90% of fibers longer than approximately 50 micrometers.

[0130] The size of the filtration system described in the application examples can be reduced by optimizing the operating conditions of the washing machine, for example, by considering more frequent but smaller-volume drainage.

Claims

1. A system for filtering microfibers contained in effluent from a textile processing apparatus, the system being intended to be connected to a drain pipe of the textile processing apparatus, characterized in that, The system includes at least: - A housing (10) comprising a particulate medium (30) occupying a portion of the space of the housing (10), the particulate medium (30) being placed on a support (20) to allow for a free volume (40) above the particulate medium (30) within the housing (10), the support (20) being at least permeable to the effluent. - A channel device (100) that allows the effluent to permeate through the particulate medium (30) includes at least one opening provided in the housing (10) and positioned above the particulate medium (30). - A device (110) for discharging the effluent includes at least one opening provided in the housing (10) and positioned below the support (20) of the particulate medium (30). - A device (120, 130) for connecting the fluidized regeneration device of the particulate medium (30), the device (120, 130) for connecting the fluidized regeneration device of the particulate medium (30) includes at least one opening provided in the housing (10) and positioned above the particulate medium (30), wherein the device (120, 130) for connecting the fluidized regeneration device of the particulate medium (30) includes means for connecting a gas suction device and / or a gas blowing device to regenerate the particulate medium (30) by fluidizing it with an airflow.

2. The system as claimed in claim 1, wherein, The means (120, 130) for connecting the fluidized regeneration device of the particulate medium (30) includes an additional opening (130) provided in the housing (10) and positioned below the support (20) of the particulate medium (30), the additional opening (130) being capable of being connected to a means for gas suction or gas blowing.

3. The system as described in any one of the preceding claims, wherein, The device (110) for discharging the effluent includes an external circuit (140) connected to the housing (10) to bypass the particulate medium when the effluent accumulates in the free volume (40) above the particulate medium (30) in the housing (10).

4. The system as described in any one of claims 1 to 2, wherein, The device (110) for discharging the effluent includes a conduit (140) that extends through the particulate medium (30) to bypass the particulate medium (30) when the effluent accumulates in the free volume (40) above the particulate medium (30) in the housing (10).

5. The system as described in claim 4, wherein, The pipe (140) is provided with a flow guide device (56) at its upper part.

6. The system of claim 3, wherein, The outer circuit (140) of the housing further includes a liquid detector.

7. The system of claim 6, wherein, The liquid detector is connected to the alarm.

8. The system of claim 4, wherein the conduit (140) of the means (110) for discharging the effluent further comprises a liquid detector.

9. The system of claim 8, wherein, The liquid detector is connected to the alarm.

10. The system according to any one of claims 1 to 2, further comprising control means (51, 52, 53, 54, 55, 57, 58, 59, 60, 61, 62) for controlling the following: channel means for the effluent to permeate through the particulate medium (30) and / or the means (110) for discharging the effluent and / or means (120, 130) for connecting the particulate medium (30) fluidized regeneration device.

11. The system of claim 10, wherein the control device comprises at least one two-way valve (51, 52, 53, 54, 55) and / or at least one three-way valve (58, 61) and / or at least one check valve (57, 59, 60) and / or a rotary six-way valve (62).

12. The system according to any one of claims 1 to 2, further comprising a sedimentation chamber and / or a cyclone separation chamber and / or a storage chamber (11) for the effluent, which is located upstream of the housing (10) and connected to the channel device (100) for the effluent to permeate through the particulate medium (30).

13. The system of any one of claims 1 to 2, further comprising an injection device for injecting at least one flocculant into the effluent, the injection device being used to inject the at least one flocculant into the effluent upstream of the particulate medium (30).

14. The system of any one of claims 1 to 2, wherein the particulate medium (30) comprises sand, crushed glass beads, raw glass beads, natural zeolite-based particles, synthetic zeolite-based particles, alumina-based particles, resin-based particles, or plastic-based particles.

15. The system of any one of claims 1 to 2, wherein the particulate medium (30) comprises at least 80% by weight of particles having a size of 0.1 mm to 2 cm.

16. The system of any one of claims 1 to 2, wherein the particulate medium (30) comprises at least 90% by weight of particles having a size of 0.3 mm to 2.5 mm.

17. The system as claimed in any one of claims 1 to 2, wherein, A liquid distributor is provided between the particulate medium (30) and the opening of the channel device (100) for the percolation of the effluent through the particulate medium (30), and / or when the fluidized regeneration device of the particulate medium (30) includes a gas suction device, a gas distributor is provided between the particulate medium (30) and the opening of the gas suction device for drawing in the gas.

18. A method for filtering microfibers contained in an effluent from a textile processing apparatus, said method being implemented by the system of any one of the preceding claims, characterized in that, The method includes at least the following steps: A) A stage of at least one microfiber filtration, the microfiber filtration stage comprising using a channel device (100) for at least one percolation of the effluent through the particulate medium (30) to allow the effluent to percolate through the particulate medium (30) at least once, and using a device (110) for at least one discharge of the effluent to discharge the filtered effluent. B) The fluidization regeneration stage is performed by connecting the device (120, 130) for connection to the fluidization regeneration device of the particulate medium (30) to the fluidization regeneration device of the particulate medium (30).

19. The method of claim 18, wherein step A) is repeated 50 to 150 times before step B).

20. The method of claim 18, wherein step A) is repeated 100 times before step B).

21. The method of any one of claims 18 to 20, comprising a step of pretreating the effluent prior to step A), the pretreating step comprising injecting at least one flocculant into the effluent at least once and / or subjecting the effluent to at least one sedimentation and / or subjecting the effluent to at least one cyclone separation.

22. The method of any one of claims 18 to 20, comprising a stage prior to step B) of discharging the particulate medium using a gas suction device connected to the system to generate a downward airflow through the particulate medium, and / or a stage of drying the particulate medium using a device to increase the temperature of the particulate medium.

23. The method of any one of claims 18 to 20, wherein the microfiber filtration stage and the fluidized regeneration stage are controlled by the control device (51, 52, 53, 54, 55, 57, 58, 59, 60, 61, 62) included in the system of claim 10 or 11.

24. The method of any one of claims 18 to 20, further comprising at least one step after the fluidization regeneration stage, comprising collecting the microfibers from the fluidization regeneration stage.

25. The method of any one of claims 18 to 20, further comprising at least one step after the fluidized regeneration stage, comprising collecting the microfibers from the fluidized regeneration stage via a membrane filter and / or cyclone chamber located downstream of the fluidized regeneration apparatus of the particulate medium (30).

26. A textile washing apparatus comprising at least one system as claimed in any one of claims 1 to 17.

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