Microplastics Compressor and Method for Compressing Microplastics

Abstract

The present invention relates to preventing microplastics from entering the environment. The present invention is directed to filtering and compressing microplastics from any wastewater, and in particular to filtering and compressing microfibers from the wastewater of washing machines and other electrical appliances. However, the present invention can also be applied in any industry where microparticles are generated, for example, in the industrial manufacture of textile products, or in the treatment of stormwater from roads, or in places where microparticles are handled, such as wastewater treatment plants. The present invention is a compressor for automatically extracting and compressing microplastics from wastewater, the compressor comprising a chamber having an inlet, at least one plate in the chamber movable between a non-compressing position and a compressing position, a drive unit for driving the at least one plate, and an outlet arranged to allow automatic discharge of the compressed microplastics.

Description

[Technical field]

[0001] The present invention relates to preventing microplastics from entering the environment. The present invention is directed to filtering and compressing microplastics from any wastewater, but in particular to filtering, compressing and automatically discharging compressed microfibers from the wastewater of washing machines and other appliances or industrial equipment or wastewater treatment plants. [Background technology]

[0002] Microfibers are the most prominent form of microplastic pollution in rivers and oceans. Due to their tiny scale, they are eaten by organisms at all levels of the food chain, from plankton to top predators. When ingested, plastics can reduce feed efficiency (false satiation), damage the animal's digestive tract, and transmit harmful additives such as PCBs, pesticides, and flame retardants to the animals that consume them. Plastics consumed by animals lower in the food chain also affect their predators, which consume large amounts of contaminated prey every day. The pervasiveness of microfibers in the food chain has naturally raised concerns about their transmission to humans, and contamination has been found in crustaceans, mollusks, and fish species intended for human consumption.

[0003] Unlike microbeads, which are readily excluded from cosmetics and cleaning products, microfibers are formed through the breakage of clothing. One third of all microplastics in the oceans come from the washing of synthetic fabrics. Synthetic fibres, derived from petrochemicals, make up 65% of all textile products. The wear and tear caused by the abrasive forces in washing machines fragments the synthetic fibres forming hundreds of thousands of microfibers less than 5mm long that flow from our homes and wastewater networks into the oceans.

[0004] Wastewater treatment plants cannot remove the millions of fibers that pass through them every day. Currently, secondary levels of water treatment remove about 98% of the microplastics that pass through them. But the small percentage that still escapes amounts to tens of millions of fibers per treatment, every day.

[0005] Additionally, wastewater treatment plants produce "sewage sludge" and plastic microfibers can be found in the discharge if released into the natural environment, or when the sludge spreads over agricultural land, thus making the microfibers make their way up the food chain, waste-to-energy (which can destroy the fibers but release harmful gases), or discharged into rivers or oceans.

[0006] Current washing machine filters are designed to stop coins and buttons that destroy the washer pump. The filtration required to stop microfibers is less than 80 micrometers (um), which is about the width of a human hair.

[0007] It is known to provide mesh filters that stop the problem at the source. For example, the filter described in Australian Patent Application Publication No. AU2019100807 has a mesh filter. However, the mesh filter quickly becomes clogged with accumulated microfibers, and when this happens, its effectiveness is greatly reduced. This can cause pressure drops, reduce flow rates, cause damage to pumps and other elements of the system, and cause flooding. While these mesh filters go some way to collecting the microfiber waste, thus preventing it from reaching the environment, they usually do not provide a convenient means for the disposal of the accumulated waste product.

[0008] A typical domestic washing machine is shown in schematic form in FIG. 1. The machine 100 includes a rotatable closed drum unit 101 for receiving the clothes to be washed. The closed drum unit 101 has a perforated cylindrical rotatable drum mounted within a static waterproof shroud. Clean water is pumped into the drum 101 via a cold water inlet 102 connected to a mains tap, typically under the mains pressure of 1 bar. The water entering the drum 101 is managed by an electronic valve under the control of a CPU 104. The inlet 102 is connected to a drawer 105 to which liquid or powder detergent may be added by the user. The drawer has an outlet leading to the drum unit 101. The drum unit can include a heater under the control of the CPU to heat the water to the desired wash temperature, typically up to 90 degrees Celsius.

[0009] The drum is rotatable by an electric motor 106 under the control of the CPU 104, typically at speeds between 5 and 1600 rpm. The drum unit can be emptied via an outlet having an electronically operated drain valve 107 and drain pump 108, both controlled by the CPU. The drain pump produces a known pressure at its output, at a given rated power. The drain pump empties into an outlet 109 which is connected to domestic or industrial wastewater and ultimately to a wastewater network.

[0010] In use, soiled laundry is placed inside the drum and the wash cycle is started by the user. The CPU causes cold water to flow through the drawer and mix with the detergent, and then the water flows into the drum where it is heated. The combination of water, detergent, and laundry is agitated by rotating the drum. During this process, dirt and grease are released into the water, as are fibers from the clothing. In the case of synthetic clothing, microfibers are typically released when the fabric rubs against itself. The resulting wastewater at the end of the wash cycle is a mixture of debris, dirt, grease, and microfibers, as well as large objects such as potentially coins or nails left on the clothing. This wastewater is then typically drained at a rate of 2 gallons per minute and pumped out of the drum. A second or third rinse cycle with fresh water is performed to produce wastewater with a lower concentration of contaminants.

[0011] In typical laundering, the high concentration of microfibers ranges from 5mm to 150um, but there are shorter microfibers that are harmful to the environment. If it is required to remove 99% of the microfibers until all sizes reach a length of 50um, a mesh with an opening of 50um can logically achieve this. However, in practice, such a mesh placed directly in the wastewater flow will clog almost immediately and the filter will become inoperable. This causes an increase in pressure consumption at the outlet and potentially damages the pump.

[0012] It is necessary to open the device and manually clean the mesh and return its pressure consumption to a level where the mesh works effectively, i.e. to regenerate its pressure consumption. Alternatively, the filter is further flushed with water and the flushed wastewater is directed and collected in a cesspit. These cesspits also need to be washed by hand periodically. Both options present a tedious and cumbersome process for the user. Alternatively, this waste is deposited in one or more cesspits in the machine. The cesspits need to be emptied frequently and cleaned to ensure the efficiency of the machine. Also, they do not directly solve the problem of preventing this waste from entering from the environment, nor do they address the problem of handling these microfibers for efficient processing. The present invention therefore seeks to overcome the problem of separating microplastic waste from the wastewater discharge stream and conveniently disposing of this waste product.

[0013] It is known to provide washing machines with a separate washing and fluid regeneration unit, see for example the disclosure of EP 1528139, where a filter is disclosed with a compressor for pushing down the concentrate and there is an outlet for passing the extraction solution, but the compressed debris needs to be removed manually by the user.

[0014] A device for the removal of solid food and fat from the wastewater of a washing machine or dishwasher is described in WO89 / 08163. The upper part of the filter is sponge-like and holds the fat, which can be squeezed out of the sponge and discharged through the outlet. However, there is no function for automatic removal of solids. Summary of the Invention

[0015] The present invention seeks to overcome the problem of separating microplastic waste from wastewater disposal streams and conveniently disposing of this waste product in an automated process that minimizes user intervention.

[0016] According to an aspect of the invention, there is provided a compactor for extracting and compressing microplastics from wastewater comprising a chamber, an inlet for feeding wastewater into the chamber, at least one plate within the chamber movable between a non-compressed position and a compressed position, a drive unit for driving the at least one plate between the non-compressed position and the compressed position, and an outlet arranged to allow for the discharge of compressed microplastics, wherein the at least one plate is operable in use to extract and compress microplastics from the wastewater, the at least one plate is arranged to move the compressed microplastics to the outlet, and the compactor is arranged such that in use the compressed microplastics are automatically discharged from the compactor via the outlet by movement of the at least one plate. A user does not need to physically wash or otherwise remove separated microplastics from the equipment as this is performed automatically by the action of the one or more plates.

[0017] The compressor may comprise a pair of cooperating plates spaced apart from one another to allow wastewater to be received and compressed therebetween, the plates being advantageously movable relative to one another along a common axis.

[0018] The first plate may be driven between the second plate by a drive unit. The second plate may be driven between the first plate by a drive unit. The first plate may move the second plate to a compressed position and the second plate may comprise a biasing element that returns the second plate to a non-compressed position. The biasing element may be a spring, a latched cam, or other stored potential energy (i.e. compressed fluid). The drive unit may be a linear actuator. The linear actuator may be a driven ram having a linear reciprocating motion. The drive means may be a manually operated drive such as a lever or push rod. The drive unit may be part of a powder detergent drawer of the washing machine.

[0019] The drive unit may be arranged to drive the plate against an end of the chamber, the end of the chamber may releasably define an outlet.

[0020] The drive unit may be a hydraulic actuator which, in use, may be operatively connected to a pressurized water supply from the washing machine.

[0021] At least one plate may comprise a permeable material. The walls of the chamber may comprise a permeable material. The permeable material may be a mesh. The chamber may comprise a wastewater outlet arranged to drain wastewater from the chamber. The chamber may be substantially cylindrical. The outlet may be in a bottom wall of the chamber arranged to drain the compacted microplastics under gravity. The outlet may comprise a removable lid. The outlet and the inlet may comprise check valves.

[0022] According to another aspect of the present invention there is provided a washing machine including a compressor of the kind provided and disclosed herein. According to another aspect of the present invention there is provided a method of operating a compressor of the kind provided and disclosed herein, the method comprising: receiving a wastewater stream; driving a plate through the wastewater from a non-compressing position to a compressing position to separate the wastewater into liquid and solid components and compress the resulting solid material, including microplastics; returning the plate to its uncompressed position; and discharging the compressed microplastics. [Brief description of the drawings]

[0023] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0024] [Figure 1] Figure 1 is a diagram of the internal workings of a standard washing machine. [Figure 2a] FIG. 2a is a diagram of an embodiment of the present invention installed in the washing machine of FIG. [Figure 2b] FIG. 2b is a diagram of an embodiment of the invention installed on the outside of the washing machine of FIG. [Figure 3a] FIG. 3a is a side cross-sectional view of an embodiment of the present invention in an uncompressed position. [Figure 3b] FIG. 3b is a side cross-sectional view of the embodiment shown in FIG. 3a in a compressed position. [Figure 3c] FIG. 3c is a side cross-sectional view of the embodiment shown in FIG. 3a in a pellet ejection position. [Figure 3d] FIG. 3d is a side cross-sectional view of another embodiment. [Figure 3e] FIG. 3e is a side cross-sectional view of another embodiment. [Figure 4] FIG. 4 is a side cross-sectional view of another embodiment of the present invention. [Diagram 5] FIG. 5 is a side cross-sectional view of another embodiment of the present invention. [Figure 6a] FIG. 6a is a side cross-sectional view of another embodiment of the invention showing the steps of compressing and ejecting microplastics. [Figure 6b] FIG. 6b is a cross-sectional side view of another embodiment of the invention showing the steps of compressing and ejecting microplastics. [Figure 6c] FIG. 6c is a cross-sectional side view of another embodiment of the invention showing the steps of compressing and ejecting microplastics. [Figure 6d] FIG. 6d is a cross-sectional side view of another embodiment of the invention showing the steps of compressing and ejecting microplastics. [Figure 7] FIG. 7 is a side cross-sectional view of another embodiment of the invention in which the rear end of the chamber opens to release the compressed microplastics. [Figure 8] FIG. 8 is a side cross-sectional view of another embodiment of the present invention in which the powder detergent drawer of the washing machine is connected to a plunger. [Figure 9] FIG. 9 is a side cross-sectional view of another embodiment of the invention arranged to pump waste water out of the chamber. [Figure 10]FIG. 10 is a perspective view of one embodiment of a compressor system coupled to a washing machine drawer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] While the following description focuses on washing machines for clothes, it should be understood that the teachings herein are not limited to use with washing machines, as they equally apply to other processing equipment, such as, but not limited to, dryers, such as tumble dryers, dyeing machines, cutting machines, recycling machines, dry cleaning machines, etc. The teachings herein may also be used in other industries where small particles may be generated as a result of the processing of items, such as, for example, equipment used in the industrial manufacture of textile products. Thus, references herein to washing machines should be understood to include any similar equipment of the type contemplated herein.

[0026] It will be further appreciated that the teachings herein are suitable for any application requiring the removal of microplastics, including microfibers, from any wastewater, including sewage, in which such materials may be entrained. Such other applications include the handling of storm water from roads in wastewater treatment plants or road drainage systems.

[0027] A typical domestic washing machine, shown in Figure 1, removes a mixture of debris, mud, grease, microfibers and other debris from dirty laundry. The resulting wastewater at the end of the wash cycle, drained from the drum, is subjected to various filtration processes in an attempt to remove the majority of contaminants before drainage. While larger items of waste can be easily captured by the filter and collected in a chamber for removal by the user, microfibers, due to their size, represent a much more difficult waste to filter. This means that conventional filters capable of stopping microfibers of around 80um in size quickly become clogged with larger debris in the 100-400um range, effectively reducing their effectiveness to zero making their use impractical. Mesh and membrane filters are usually disposable cartridges. However, this adds to the problems of plastic waste disposal, as when filled with around 1 gram of microfiber, the cartridge weighs over 150 grams on its own, requiring frequent replacement. For example, the multi-stage mesh-based filtration system described in UK Patent Application No. GB1914545.7 is very efficient at separating microfibers from wastewater streams, and the separated microfibers are deposited in cesspits. These cesspits contain dirty wastewater that is difficult to drain from the machine. The cesspits are often dumped into sewers, defeating the purpose of the separation process as the waste enters the household drainage system.

[0028] An embodiment of the present invention provides a microplastic extraction and compression chamber, shown in Figure 2a, that removes accumulated microplastic fibers from wastewater contained in a cesspit and compresses these microfibers into pellets for easier processing through household waste collection, thereby reducing packaging size and weight and improving the ability to send the fibers into the circular economy. After all water has been removed from the material separated from the wastewater, a lightweight pack of material remains that can be handled very efficiently.

[0029] FIG. 2a shows an embodiment of a compressor 200 as part of a domestic washing machine 100. The compressor 200 may be integrated into the mechanism of the washing machine 100 by the manufacturer. Alternatively, the compressor 200 is a stand-alone unit that may be added to the wastewater outlet of an existing washing machine 100 shown in FIG. 2b, typically with an external filter unit 110, to receive and process the filtered waste from the filter unit 110. The filter unit 110 may be of the type described in UK Patent Applications GB1914545.7 and GB1914548.1. The compressor 200 is configured to receive wastewater 203 from any sump or filtered wastewater outlet in the washing machine 100 or filter unit 110. The compressor 200 produces compressed microplastic 207 waste products in the form of pellets from the wastewater 203. The compactor 200 provides an additional filtration process for the wastewater that removes all microplastic particles and results in wastewater 209 from a wastewater outlet 208 suitable for connection to a domestic drainage system. The resulting compacted pellets can then be conveniently handled by the user and disposed of environmentally responsibly, for example by sending the pellets to a recycling facility.

[0030] Figures 3a-3c show an embodiment of the compressor 200 in its basic form, comprising a chamber 201 for receiving wastewater 203 through an inlet 202. An outlet 206 is provided in the chamber 201. A plate 204 is disposed in the chamber 201 and is coupled to a drive unit 205. Figure 3a shows the plate in a retracted or uncompressed position before engaging the drive means. An inlet valve is provided near the inlet 202 (not shown) that can control the flow of wastewater into the chamber 201. The flow of wastewater is not continuous, but is controlled by the inlet valve to fill the chamber and then close. Alternatively, the inlet valve can be operated such that the separator sump is emptied into the chamber 201 and then closed so that the sump can refill.

[0031] The outlet 206 can be opened and closed. During the operating cycle, the inlet valve is opened to allow wastewater into the chamber 201, and at the same time the outlet is closed so that the wastewater cannot escape. The plate 204 can be driven by the drive unit 205 through the wastewater 203 that has entered the chamber 201, compressing the microplastic objects, in particular by being compressed between the plate 204 and the wall of the chamber 201, as shown in Fig. 3b. The microplastic objects are effectively collected from the wastewater 203, squeezed, removing all the liquid, resulting in a compacted microplastic solid. The plate 204 is pulled by the action of the drive unit 205 in the opposite direction to release the solid, as shown in Fig. 3c. The outlet is opened to release both the compacted microplastics and the separated fluid. The compacted microplastics are in a form that can be easily and conveniently processed by the user.

[0032] The outlet 206 may be configured within the chamber 201 such that when the outlet 206 is open, the compressed microplastics 207 pieces will gravitationally exit the chamber 201. Alternatively, although not shown, an exhaust mechanism may be incorporated within the chamber 201 to push the compressed microplastics 207 out through the outlet.

[0033] The elements of the compressor 200 are permeable to allow water to flow out while the chamber is compressed. The pores of the permeable structure may be approximately 50 micrometers in diameter so that microfibers larger than this size cannot pass through. Other sizes are possible, as discussed below. The permeable structure may be a plate 204, which may be made of a rigid mesh or a flexible mesh supported by a framework. In this embodiment, the water flows out the rear of the chamber behind the plate 204 through a drainage channel 208 as shown in FIG. 3d. Alternatively, the rear wall 211 of the chamber 201 may be permeable and may be provided with a drainage channel 212 to move the wastewater out of the compressor, as shown in FIG. 3e. Alternatively or additionally, the outlet 206 may be openable with a permeable flap 213, as shown in FIGS. 3d and 3e, which is in a closed position during compression of the wastewater and opens to allow the compressed pellets to exit. A flap 214 is provided at the inlet to prevent waste water from flowing out of the inlet during the compression phase.

[0034] Suitable permeable materials include mesh. The ideal mesh opening is 80um, which can stop 99.4% of the 25um sized microfibers. However, a smaller opening size means that it will clog faster and the flow rate will be reduced. Larger mesh sizes can be used anywhere up to 400um. The advantage of using a larger mesh opening is that it is stronger than a smaller opening mesh and can be manufactured cheaper by molding. However, the water removed by this mesh will contain a significant proportion of microfibers, so it will need to be returned to the filtration stage for separation.

[0035] The drive unit 205 may comprise a linear actuator for moving the plate 204 from an uncompressed position to a compressed position. The linear actuator may be a driven ram with a linear reciprocating motion. On the forward stroke, the plate 204 moves from the uncompressed position to the compressed position through any waste water 203 in the chamber 201, collecting any accumulated waste and moving and squeezing the accumulated waste against the walls of the chamber 201. On the reverse stroke, the plate 204 moves from the compressed position back to the uncompressed position, releasing the now compressed waste, which is urged into position for discharge through the discharge port 206.

[0036] The drive unit 205 may comprise a hydraulic actuator for providing the linear reciprocating motion required to move the plate 204 from the uncompressed to the compressed position. This fluid motor may be supplied with pressurized water from a washing machine or mains water pressure.

[0037] The compactor 200 may incorporate a single plate 204 for compacting the waste material. Alternatively, the compactor 200 may include additional plates for compacting the waste material. The plate 204 may be formed of a permeable material, such as a mesh, configured to pass through the wastewater 203 while extracting microplastic fibers from the wastewater 203, retaining these microplastic fibers on its flat compression surface while allowing the resulting wastewater, now free of microplastic fibers, to pass through the plate 204 for disposal via a standard drainage system, i.e., to the outlet 109 in the washing machine fitting shown in Figures 2a and 2b.

[0038] In this and all other embodiments of the invention, the outlet and inlet preferably include check valves.

[0039] 4 illustrates another embodiment of the invention showing compressor 200 with a pair of cooperating plates 204a and 204b in chamber 201. The pair of cooperating plates 204a and 204b in a non-compressing configuration are spaced apart to allow wastewater 203 to be received therebetween. Wastewater 203 is provided through inlet 202. The pair of cooperating plates 204a and 204b are substantially parallel with flat surfaces facing each other and are movable between each other along a common axis in this embodiment.

[0040] Each of the plates 204a and 204b is configured to be driven by a drive unit 205a and 205b, respectively. The drive units 205a and 205b may be any combination of linear or hydraulic actuators suitable for driving the plates 204a and 204b towards each other. The plates 204a and 204b are formed of a permeable material such that upon compression of the wastewater 203, the wastewater 209 passes through the wastewater outlet 207.

[0041] The deposited microplastics are compressed between plates 204a and 204b to form a compressed solid pack. Plates 204a and 204b return to their uncompressed positions, and in so doing move the compressed microplastics 207 into alignment for discharge through outlet 206 by appropriate actuation of drive units 204a and 204b.

[0042] FIG. 5 shows another embodiment of the compactor 200, in which the first plate 204a is driven by the drive unit 205 and the second plate 204b is supported in position by the biasing element 210. The first plate 204a is driven by the drive unit 205a towards the second plate 204b, compressing the microplastics therebetween. The first plate 204a moves the second plate 204b in the same direction against the resistive force generated by the biasing element 210. A latch is provided (not shown) so that the second plate 204b can be latched in the open position. When the compression phase is over, the first plate 204a returns to its uncompressed position and the second plate 204b remains in the open position. When the compressed microplastics 207 are free from both plates and aligned with the outlet 206, they can fall out. The second plate 204b can then be reset by releasing the latch, causing it to return to its original uncompressed position, driven by the biasing element 210. The biasing element 210 may comprise a spring.

[0043] To aid in the discharge of the compressed microplastics 207 through the discharge port 206 and the wastewater 209 through the wastewater outlet 208, the chamber 201 can be configured to be mounted at an angle as shown in Figures 6a, 6b and 6c. This angle allows the discharge of the compressed microplastics 207 under gravity without requiring any additional mechanical elements. It also makes the cleaning operation of the compactor 200 much more convenient for the user.

[0044] Figures 6a, 6b and 6c show the passage of waste water 203 through the compressor 200 when in its uncompressed configuration, when in its compressed configuration and when in its discharge configuration. The waste water 203 enters the chamber 201 of the compressor 200 through the inlet 202 or through a waste hose, not shown, when the washing machine sump is emptied. The drive means 205 is actuated to drive the first plate 204a along the chamber 201, collecting microplastic fibres from within the waste water 203 as the mesh-type plate moves. The filtered water or waste water 209 passes through the plate 204a for discharge through the waste water outlet 208. The accumulated microplastic fibres are swept together, swept into each other and swept into the second plate 204b, as shown in Figure 6b. By compressing the microplastic fibres between the plates 204a and 204b, any remaining liquid is also squeezed and the fibres themselves are compressed to form a solid or pack. The solids include compressed microplastics 207 that are effectively dried via squeezing, thus forming pellets or pucks.

[0045] The first plate 204a drives the second plate 204b further along the chamber 201 against the biasing element 210 until it reaches the end of its travel, at which point the second plate 204b latches in the open position.

[0046] When the drive means 205a reverses, the first plate 204a is moved away from the second plate 204b, and the first plate 204a returns to its starting position, as shown in Figure 6c. The latched second plate remains where it is and the compressed micro-plastic pellets are then free to fall out of the outlet 206. The cycle is reset by the second plate returning to its unlatched starting position. This can be accomplished with a push rod that releases the latch as the first plate 204a returns to its starting position.

[0047] The user retrieves the compressed microplastics 207 from the chamber 201 by opening either a trap door or a removable lid, not shown. In other embodiments, the discharge of the compressed microplastics 207 may be an automated part of the process, whereby the return pass of the first plate 204a and the drainage of any remaining waste water 209 opens the discharge port 206 or releases its grip to do so. The compressed microplastics 207 fall out of the chamber 201 of the compactor 200.

[0048] In the embodiment shown in Figure 6d, the chamber is mounted at an angle to allow waste water to drain out of the outlet 208, but the plates 204a, 204b are oriented vertically, thereby forming a parallelogram with the sides of the chamber, which allows the compressed pellets to be easily released under gravity from the face of the first plate 204a.

[0049] 7 shows another embodiment of the invention in which the plate 204a is non-porous. The bottom wall of the chamber 201 comprises a mesh structure 705 beneath which is a collection trough 704 which directs the water to the outlet 208. The end wall of the chamber 201 is a solid flap 702 with a hinge joint 703 which can swing to allow access to the interior of the chamber 201. The chamber has a latch 701 to hold the flap closed. The latch 701 is actuated by a push rod (not shown) connected to the plate 204a so that when the plate reaches the full length of its travel it actuates the latch and causes the door to swing open. A mechanism (not shown) is provided to close the flap 702 and re-close the latch. In use, wastewater enters chamber 201 through inlet 202 and actuator 205a moves piston 204a through the chamber, squeezing the water from the wastewater through mesh 705 and out outlet 208 until piston 204a presses firmly against flap 702 forming a pellet or puck of waste material including microfibers. At this point latch 701 is actuated, the flap opens and the pellets are removed for further processing. Actuator 205a then retracts the piston, closes the flap and recloses the latch in preparation for the next cycle.

[0050] FIG. 8 shows another embodiment of the invention, including the addition of check valves 801, 802 at the inlet and outlet, respectively, and the inlet moved towards the flap 702. In this arrangement, the action of retracting the piston after its compression stroke has the effect of drawing wastewater into the chamber 201. The action of pushing the piston during its compression stroke closes the inlet check valve 801 and pumps wastewater out of the outlet 208. In FIG. 9, it can be seen that by using this arrangement, the water extracted from the wastewater can be pumped back into the system via pipe 804 where it can be re-filtered if necessary. This may be required if the openings in the mesh 705 are large, for example 400um. This arrangement is in effect a pump that can potentially replace the washing machine pump. The user can operate the drawer repeatedly until the washing machine drum is emptied of wastewater, or this can be automated as a piston on drive, and the wastewater has passed through the filtering and compression stages to remove and recycle the resulting solid material extracted from the wastewater that has run out of the washing machine.

[0051] A further addition shown in Figure 8 is a piston 204a which is connected to the detergent powder drawer 803 when the unit is installed in a washing machine. The action of the user opening the drawer causes waste water to be drawn into the chamber 201 whilst the action of the user closing the drawer causes the plate 204a to move through the waste water squeezing and compressing the water against the flap 702 until the flap opens and the pellets are released.

[0052] An arrangement in which the compression cycle is driven by the action of opening and closing a washing machine's powder detergent drawer is shown in Figure 10. The drawer 1001 travels on guide rails 1007, the end of which presses against an actuator 1002. The actuator is connected to a piston in a cylinder 1003. Waste water enters through an inlet (not shown) and extracted water exits through an outlet (not shown) potentially returning to the washing machine drum for use in the next wash. The end of the cylinder 1003 has a spring-loaded flap 1004 which springs open when a latch 1005 is actuated. The latch 1005 is released by an activator 1006 which is connected to the drawer 1001. [Prior art documents] [Patent documents]

[0053] [Patent Document 1] Australian Patent Application Publication No. AU2019100807 [Patent Document 2] European Patent Publication No. EP1528139

Claims

1. A compressor for extracting and compressing microplastics from wastewater, comprising: A chamber (201); an inlet (202) for supplying waste water to said chamber; a wastewater outlet (208) configured to drain the wastewater from the chamber; at least a first plate (204a) in the chamber, the first plate having a first flat surface and movable between a non-compressed position and a compressed position during a compression phase; a second planar surface provided by a second plate (702) in the chamber or by a wall of the chamber, the second planar surface being substantially parallel to the first planar surface; a drive unit (803) for driving the first plate between the uncompressed position and the compressed position during the compression phase; a permeable element (705) that allows waste water to flow out of said chamber during said compression phase; and an outlet (702) arranged to allow the discharge of the compressed microplastics, the inlet includes a check valve (801) for preventing waste water from flowing out of the inlet during the compression phase; A compressor, wherein in use, the compressor is operable to extract the microplastics from wastewater and compress the microplastics between the first and second flat surfaces to squeeze out remaining liquid and form a compressed microplastic solid, and the first plate is positioned to move the compressed microplastics to the outlet for automatic discharge from the compressor via the outlet.

2. A compressor as described in claim 1, wherein the second flat surface is provided by the second plate such that the first and second plates comprise a pair of cooperating plates spaced apart from each other so as to be able to receive and compress wastewater therebetween, and the plates are movable between each other.

3. The compressor of claim 2 , wherein the first plate is driven between a second plate by the drive unit.

4. The compressor of claim 3 , wherein the second plate is driven between the first plate by the drive unit.

5. The compressor of claim 3 , wherein the first plate moves the second plate to a compressed position, and the second plate includes a biasing element for returning the second plate to the uncompressed position.

6. The compressor of claim 1 , wherein the second planar surface is provided by an end wall of the chamber, and the drive unit is arranged to drive the first plate against the end wall of the chamber.

7. The compressor of claim 6 , wherein the end wall of the chamber is openable and defines the discharge port.

8. The compressor of any one of claims 1 to 7, wherein the drive unit comprises a linear actuator.

9. The compressor according to any one of claims 1 to 8, wherein the drive unit is a manually operated drive comprising a lever or a push rod.

10. The compressor according to any one of claims 1 to 9, wherein the drive unit is coupled to a drawer of a washing machine.

11. The compressor according to any one of claims 1 to 10, wherein the drive unit is a hydraulic actuator.

12. A compressor as described in claim 10, wherein the drive unit is a hydraulic actuator, and wherein the hydraulic actuator, in use, is operably connected to a pressurized water supply from the washing machine.

13. 13. The compactor of any one of claims 1 to 12, wherein the outlet is in a lower wall of the chamber arranged to discharge the compacted microplastics under gravity.

14. A method of operating a compressor of the kind claimed in claims 1 to 13, comprising the steps of: receiving a wastewater stream; driving the first plate through the wastewater from an uncompressed position to a compressed position to separate water from the wastewater through the permeation element and compress the resulting material including microplastics; returning the first plate to an uncompressed position; and discharging the compressed microplastics.

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