Micro-plastic recovery system

Abstract

Provided is a microplastic recovery system capable of selectively recovering microplastic from environmental water. A microplastic recovery system (1) according to one embodiment of the present invention is a microplastic recovery system for recovering microplastic from environmental water, and is provided with: a settling separator (20) which forms an upflow of environmental water and settles and separates a heavy component of suspended solids from the environmental water; and a filter (30) for filtering the environmental water from which the heavy components of the suspended solids have been removed by the settling separator (20).

Description

Technical Field

[0001] The present invention relates to a microplastic recycling system. This application claims priority based on Japanese Patent Application No. 2023-18680 filed in Japan on February 9, 2023, the contents of which are incorporated herein by reference. Background Art

[0002] Plastics make up a significant portion of marine debris and are becoming a growing threat. Addressing marine pollution from suspended pollutants, including microplastics, is a particularly pressing issue. While ships typically take in and discharge large amounts of ambient water for cooling and ballast water, the suspended pollutants contained in this water are not effectively recovered and treated.

[0003] Therefore, a proposal has been made to filter the ambient water taken into a ship with a filter to recover suspended pollutants such as microplastics (for example, Patent Document 1).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2022-67738 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] In addition to microplastics, ambient water also contains suspended solids from the natural environment, such as sand, wood, and seaweed fragments. Separating and recovering these naturally derived suspended solids along with microplastics increases the amount of material recovered and the processing costs. Therefore, the present invention aims to provide a microplastic recovery system that can be widely applied to ships and other vessels and can selectively recover microplastics from ambient water.

[0009] Means for solving problems

[0010] According to one embodiment of the present invention, a microplastic recovery system is a microplastic recovery system for recovering microplastics from environmental water. The microplastic recovery system comprises: a sedimentation separator, which forms an upward flow of environmental water and sediments and separates heavy suspended solids from the environmental water; and a filter, which filters the environmental water from which the heavy suspended solids have been removed by the sedimentation separator.

[0011] In the microplastic recovery system, the inlet flow rate of the ambient water in the sedimentation separator is greater than 0.5 m / s and less than 1.5 m / s.

[0012] In the microplastic recovery system, the sedimentation separator forms a spiral upward flow of ambient water.

[0013] The microplastic recovery system further comprises, on the upstream side of the sedimentation separator, a primary separator, which separates the ambient water into ambient water with a reduced concentration of suspended solids and ambient water with an increased concentration of suspended solids, and introduces the ambient water with an increased concentration of suspended solids flowing out of the primary separator into the sedimentation separator.

[0014] In the microplastic recovery system, heavy components of suspended solids are discharged from below the inlet of the ambient water of the sedimentation separator.

[0015] Effects of the Invention

[0016] According to the present invention, a microplastic recovery system can be provided, which can be widely used in ships and the like and can selectively recover microplastics from ambient water. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram showing the structure of a microplastic recovery system according to a first embodiment of the present invention. DETAILED DESCRIPTION

[0018] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1 Schematic diagram showing the structure of a microplastic recovery system 1 according to one embodiment of the present invention.

[0019] The microplastic recovery system 1 is a microplastic recovery system that removes and recovers microplastics from environmental water (seawater, river water, lake water, etc.). The microplastic recovery system 1 can be installed in a path where environmental water is taken in and introduced into demand equipment such as ballast tanks and cooling devices, or it can be installed in a path where used environmental water is released from demand equipment into the environment.

[0020] The microplastic recovery system 1 comprises: a primary separator 10, which separates ambient water (raw water) into ambient water (low-concentration water) with a reduced concentration of suspended solids and ambient water (high-concentration water) with an increased concentration of suspended solids; a sedimentation separator 20, which forms an upward flow of ambient water (high-concentration water), sediments and separates the heavy components of suspended solids (suspended solids with a high sedimentation rate) from the ambient water, and allows intermediate treated water containing light components of suspended solids to flow out; and a filter 30, which filters the ambient water (intermediate treated water) after the heavy components of suspended solids have been removed by the sedimentation separator 20.

[0021] In order to enable these components to function, the microplastic recovery system 1 has: a primary supply pipeline 40 that supplies ambient water to the primary separator 10; a secondary supply pipeline 50 that introduces high-concentration water flowing out of the primary separator 10 to the sedimentation separator 20; a main discharge pipeline 60 that leads the low-concentration water flowing out of the primary separator 10 to the outside of the system; an intermediate pipeline 70 that introduces the intermediate treated water that has passed through the sedimentation separator 20 to the filter 30; a filtered water pipeline 80 that leads the filtered water that has passed through the filter 30; a sludge discharge pipeline 90 that discharges heavy components from the lower part of the sedimentation separator 20 to the outside of the system; and a bypass pipeline 100 that allows high-concentration water to flow out of the secondary supply pipeline 50 to the main discharge pipeline 60 or the filtered water pipeline 80.

[0022] The primary separator 10 can be, for example, a cyclone separator that forms a swirling flow through a flow path structure to cause centrifugal force to act on the water to be treated, a continuous centrifuge that causes centrifugal force to act on the water to be treated by the rotation of a motor, or a separator that uses a separation membrane to separate water into low-concentration water and high-concentration water. Figure 1 In the embodiment, the primary separator 10 is intended to be a cyclone separator.

[0023] The sedimentation separator 20 forms an upward flow at a higher speed than the sedimentation velocity of microplastics, for example, sedimenting the heavy components of suspended solids such as sand whose sedimentation velocity is greater than that of microplastics, and causing the light components of suspended solids with a low sedimentation velocity to flow out. That is, the sedimentation separator 20 removes heavy components from the high-concentration water flowing out of the primary separator 10. Here, the suspended solids are affected differently by the water flow according to their specific gravity, shape, and size. For example, even with the same specific gravity, plate-like solids are more strongly affected by the water flow than block-like solids and are easily accompanied by the water flow. Since microplastics are easily accompanied by the upward flow, the sedimentation separator 20 based on the upward flow can effectively separate microplastics and soil particles, etc., compared with simple specific gravity separation or simple sedimentation separation.

[0024] The sedimentation separator 20 preferably forms a spiral upward flow of the ambient water. By forming a flow in the circumferential direction, it is possible to suppress the shedding of particles near the wall surface that would exist in a straight upward flow. This can suppress the deviation of the retention time of the ambient water and improve the separation effect of suspended solids. The inlet flow rate of the ambient water in the sedimentation separator 20 is preferably 0.5 m / s or more and 1.5 m / s or less. As an example, when the inlet of the sedimentation separator 20 is formed by a pipe with a nominal diameter of 25A and the main body of the sedimentation separator 20 is formed by a pipe with a nominal diameter of 100A, the flow rate of the upward component is between 0.042 m / s and 0.085 m / s. By forming an upward flow containing such a swirling component, it is possible to obtain the effect of separating suspended solids by water flow in addition to gravity.

[0025] The filter 30 captures suspended solids in the intermediate treatment water. As the filter 30, it is preferred to have a structure such as a tube well filter with a bucket-shaped filter material, a cartridge filter, etc. that can easily recover the captured suspended solids. The microplastic recovery system 1 may also have a plurality of filters 30 arranged in parallel so that the filter material of the filter 30 can be replaced while continuing to operate. In addition, a filter of the type that backwashes the filter and a cartridge filter that filters suspended solids from the backwash water may be combined. The filter 30 or the flow path before and after it has a differential pressure gauge 31 in order to detect blockage of the filter 30. The detection of blockage of the filter 30 can also be used to determine the necessity of using the bypass line 100.

[0026] The primary supply line 40 supplies ambient water to the primary separator 10. If necessary, the primary supply line 40 may be provided with equipment such as a pump, a flow meter, a pressure gauge, and a valve (not shown).

[0027] The secondary supply line 50 is configured to guide the high-concentration water flowing out of the primary separator 10 to the sedimentation separator 20. The secondary supply line 50 may be configured to include a shutoff valve 51 for shutting off the outflow of the high-concentration water from the primary separator 10.

[0028] The main discharge line 60 leads the low-concentration water flowing out of the primary separator 10. The primary separator 10, which is composed of a cyclone separator, does not clog and always allows the ambient water with a reduced concentration of suspended solids to flow out to the main discharge line 60.

[0029] The intermediate pipeline 70 removes heavy components of suspended solids from the high-concentration water through the sedimentation separator 20, and introduces the intermediate treated water with an increased ratio of microplastics in the suspended solids into the filter 30. The intermediate pipeline 70 preferably has a shutoff valve 71 that blocks the flow path for maintenance of the filter 30.

[0030] In this embodiment, the filtered water line 80 directs the filtered water from which suspended solids have been removed in the filter 30 into the main discharge line 60, but the filtered water may also be discharged separately outside the system. As an example, the filtered water line 80 may also be configured to include a pressure pump (not shown) to direct the filtered water into the main discharge line 60. In addition, the main discharge line 60 may also be configured to supply ambient water to the demand equipment, and the filtered water line 80 may discharge the filtered water outside the system. The secondary supply line 50 preferably has an adjustment valve 81 for adjusting the outflow of filtered water from the filter 30, the outflow of high-concentration water from the primary separator 10, and the outflow of intermediate treated water from the sedimentation separator 20.

[0031] The sludge discharge line 90 discharges the heavy components of the settled suspended solids from below the ambient water inlet of the sedimentation separator 20, along with a small amount of drainage. The sludge discharge line 90 may have an adjustment valve 91 for adjusting the discharge rate of the ambient water containing the suspended solids. The sludge discharge line 90 may discharge the heavy components of the suspended solids intermittently, or it may continuously discharge drainage containing the heavy components at a flow rate sufficiently small relative to the flow rate of the ambient water discharged from the sedimentation separator 20 to the intermediate pipeline 70. The heavy components discharged from the sludge discharge line 90 may be disposed of as industrial waste, but since they are believed to be mainly sand, they may also be released into the environment. By discharging the heavy components of the suspended solids from the bottom of the sedimentation separator 20 using the sludge discharge line 90, it is possible to prevent a reduction in the separation capacity of the sedimentation separator 20.

[0032] When the filter 30 is blocked or during the operation of recovering suspended solids from the filter 30, the bypass line 100 allows the high-concentration water flowing out of the primary separator 10 to flow directly from the secondary supply line 50 to the filtered water line 80. In the illustrated embodiment, the bypass line 100 has an automatic valve 101 that opens when the differential pressure gauge 31 detects a predetermined pressure. In this way, the blockage of the filter 30 can be automatically detected, and necessary operations such as filter replacement can be performed. In addition, the ambient water can also flow directly from the primary supply line 40 to the main discharge line 60 without passing through the primary separator 10, but by providing the bypass line 100 on the secondary supply line 50, the bypass line 100 can be formed by a relatively small diameter pipe.

[0033] In the microplastic recovery system 1, heavy components of suspended solids such as sand are separated by sedimentation in the sedimentation separator 20 and then filtered through the filter 30, thereby increasing the proportion of microplastics in the suspended solids recovered in the filter 30. This reduces the load on the filter 30 and prevents clogging, thereby enabling efficient recovery of microplastics from ambient water.

[0034] Moreover, since the microplastic recovery system 1 is provided with a primary separator 10 on the upstream side of the sedimentation separator, it is possible to perform a primary treatment in the primary separator 10 to separate the ambient water into low-concentration water with a small content of microplastics and high-concentration water with a large content of microplastics. As a result, the high-concentration water with a large content of microplastics is significantly reduced in volume compared to the ambient water (for example, less than 5% of the amount of ambient water), so the sedimentation separator 20 can be miniaturized compared to the processing volume of the ambient water, which can reduce the cost of the entire system. In addition, even if blockage occurs in the sedimentation separator, filter, or the piping connecting them, the impact on the ambient water can be suppressed.

[0035] While various embodiments of the present invention have been described above, the present invention is not limited to these embodiments and is capable of various modifications and variations. For example, the microplastics recovery system 1 may not include a primary separator, a primary supply line, or a main discharge line. Furthermore, the bypass line in the microplastics recovery system 1 may also have an optional configuration, such as manual switching.

[0036] Description of Reference Numerals

[0037] 1Microplastic recycling system

[0038] 10 Primary separator

[0039] 20 sedimentation separator

[0040] 30 filters

[0041] 31 Differential pressure gauge

[0042] 40 primary supply pipeline

[0043] 50 secondary supply pipeline

[0044] 51 blocking valve

[0045] 60 main discharge line

[0046] 70 intermediate pipeline

[0047] 71 blocking valve

[0048] 80 filtered water line

[0049] 81 regulating valve

[0050] 90 sludge discharge pipeline

[0051] 91 regulating valve

[0052] 100 bypass line

[0053] 101 automatic valve.

Claims

1. A microplastic recovery system for recovering microplastics from environmental water, characterized in that: The microplastic recycling system has: a sedimentation separator that forms an upward flow of ambient water and separates heavy components of suspended solids from the ambient water by sedimentation; and A filter filters the environmental water from which heavy components of suspended solids have been removed by the sedimentation separator.

2. The microplastic recycling system according to claim 1, characterized in that: The inlet flow velocity of the ambient water in the sedimentation separator is greater than or equal to 0.5 m / s and less than or equal to 1.5 m / s.

3. The microplastic recycling system according to claim 1 or 2, characterized in that: The sedimentation separator forms a spiral upward flow of the ambient water.

4. The microplastic recycling system according to claim 1 or 2, characterized in that: A primary separator is further provided on the upstream side of the sedimentation separator, which separates the ambient water into the ambient water with the suspended solids concentration reduced and the ambient water with the suspended solids concentration increased. The environmental water discharged from the primary separator and having a suspended solids concentration increased is introduced into the sedimentation separator.

5. The microplastic recycling system according to claim 1 or 2, characterized in that: The microplastic recovery system includes a discharge pipeline for discharging heavy components of suspended solids from below the ambient water inlet of the sedimentation separator.

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