Patent Publication Number: US-2022219176-A1

Title: Flocculation and Magnetic Separation Device; System for Purifying Marine Plastic, Microplastic, and Ballast Water Having the Flocculation and Magnetic Separation Device; Ship Equipped with the System; and Operation Method of the Ship

Description:
TECHNICAL FIELD 
     The present invention relates to a low-cost and space-saving flocculation and magnetic separation device; and relates to a purifying system for marine plastic, microplastic, and ballast water, and relates to a ship equipped with the purifying system; and further relates to a method of operation of the ship. The invented device flocculates floating matter in a fluid a together with magnetic substances such as magnetite to produce flocs and makes the flocs so flocculated contact with a magnetic drum having magnets to allow effective and eased separation from the fluid, wherein the magnetic drum rotates in the opposite direction to the direction of the flow of the fluid containing floating matter. 
     BACKGROUND ART 
     There exist Patent Documents 1 to 4 as background techniques in the technical field of the present invention. 
     Patent Literature 1 discloses a magnetic drum type flocculation and magnetic separation device in which the drum rotates in the same direction as the flow direction of the fluid. 
     Patent Literature 2 discloses a ballast water treatment method; in which, in sucking plankton or the like in the ocean by a pump into a ballast tank, the plankton is broken by a slit and further ozone-sterilized. 
     Patent Literature 3 discloses a method of a ballast water treatment system. In the system, the treated ballast water is subjected to a water quality inspection, and if the inspection result does not satisfy the values specified in the ballast water discharge regulation, the ballast water treatment is performed again. 
     Patent Literature 4 discloses a method of cleating a planned course that will reduce the occurrence of a complicated route relationship with other ships that is hard to determine a safe course while maintaining economic efficiency in selecting the course. 
     CONVENTIONAL ART 
     Patent Literature 
     
         
         {Patent Literature 1} Japanese Published Unexamined Patent Application No. 2016-101539 
         {Patent Literature 2} Japanese Published Unexamined Patent Application No. 2008-86892 
         {Patent Literature 3} Japanese Published Unexamined Patent Application No. 2015-51764 
         {Patent Literature 4} Japanese Published Unexamined Patent Application No. 2018-73074 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     Plastic discarded into the ocean has become a global ocean pollution problem. In addition, these plastics are broken down into small pieces by ultraviolet light and fluid power. These plastics and microplastics, which are tens of microns to several millimeters in size, are accidentally introduced into the body of fish and other aquatic organisms as food. It has been reported that some marine organisms die as a result. In addition, microplastics may have harmful substances attached to them, and there are concerns that eating fish that contain such microplastics may have an enormous impact on human health. Therefore, a method is desired to removing plastics and microplastics floating in the ocean. 
     In Patent Literature 1, floating matters and magnetite in raw water are aggregated to form flocs, and a fluid containing the flocs flows toward a magnetic drum that rotates in the same direction as the flow of the fluid. A weir is provided to control the flow rate and the flocs are separated from the water and recovered by magnetic force. However, in this method, since the flow direction of the fluid and the rotation direction of the magnetic drum are in the same direction, the fluid is accelerated in the flow direction of the drum due to the viscosity of the fluid. Therefore, the fluid that has passed over the weir is accelerated by the rotation of the drum, so that flow separation occurs at the corners of the weir, then a shearing force acts on the flocs around the weir, thus the flocs are easily broken. Therefore, in order to prevent the magnetic flocs break, it is necessary to reduce the rotation speed of the drum and the flow velocity of the pump. In addition, the size of the floc is several hundred microns to several millimeters, which is much larger than that of a fluid molecule, for example, a water molecule, therefore the fluid resistance is large. In order for the flocs to be attracted to the magnetic drum by the magnetic force acting in the direction perpendicular to the flow direction without breaking the flocs, a certain amount of time is required for the flocs to approach the magnetic drum, and the flow speed cannot be increased for the above reasons. Therefore, in order to increase the flow rate, the flow channel area must be increased, and in addition, the diameter of the magnetic drum must be increased, or alternatively, the number of magnetic drums must be increased. Because of this, there left a problem that increasing the flow rate would make the device large. 
     In Patent Literature 2, in order to kill plankton and other aquatic organisms in the water, at the time when ballast water is pumped in, the plankton and other organisms are broken by slits, and then the plankton is sterilized by ozone or other means. However, this method has a problem that the method cannot solve marine pollution caused by plastics and microplastics. 
     In Patent Literature 3, a ballast water purification system has been disclosed. In the disclosed art, the ballast water is treated by flocculation and magnetic separation while monitoring the water quality. However, no consideration was given to the removal of plastics or solving marine pollution problems. 
     In the art described in Patent Literature 4, the course information of other ships in the vicinity of the sea area through which specific vessels pass is obtained and accumulated. With that course information, efficient course plan information is produced. However, no consideration was given to marine pollution by discarded plastics. 
     Solution to Problem 
     To solve the above-stated problem, the present invention proposes a flocculation and magnetic separation device. 
     The invented device comprises: 
     a stirrer that produces flocs by putting flocculant, magnetic material, and polymer into a fluid containing plastic and plankton and agitating that fluid; 
     a first magnetic drum having magnets on the surface thereof to attract the flocs thereon, wherein 
     the first magnetic drum rotates in the direction opposite to the flow direction of the floc-contained fluid to create eddies for attracting the flocs thereto; 
     a second magnetic drum having magnets on the surface thereof to attract the flocs, wherein 
     this second magnetic drum rotates in the same direction as a fluid of which flow direction being changed at a bump-like protrusion arranged at the rear of the first magnetic drum so that the fluid will not cause peeling off of the flocs attracted to the second magnetic drum; and 
     a floc recovering section for recovering by grouping the flocs attracted to the first magnetic drum and to the second magnetic drum into one. 
     The flocculation and magnetic separation device by the present invention, comprises: 
     a stirrer that produces flows by putting flocculant, magnetic material, and polymer into a fluid containing plastic and plankton and agitating that fluid; 
     a rotating drum having a non-magnetic surface rotating in the same direction as the flow of said floc-containing fluid to flow said flocs; and 
     a magnetic drum having magnets on the surface thereof to attract the flocs thereon, wherein the magnetic drum rotates in the direction opposite to the flow direction of the floc-contained fluid, wherein the floc-contained flow is a direction-changed flow changed at the bump-like protrusion provided rear of the rotating drum so as to attract the flocs to the magnetic drum; and 
     a floc recovering section for recovering the flocs attached to the magnetic drum. 
     The flocculation and magnetic separation device comprises a pipe, into which a fluid containing plastic broken by a slit mechanism flows; 
     wherein the slit mechanism has: 
     a first slit section provided on the pipe at a predetermined angle and 
     a second slit section provided at the rear stage of the first slit section at a predetermined angle different from the predetermined angle; 
     wherein the cross section of both a slit plate of the first slit section and a slit plate of the second slit section is acute with respect to the flow-in direction. 
     Advantageous Effects of Invention 
     The present invention provides a small-sized low-cost floc recovering device. The invented device is able to recover flocs using magnetic force without breaking them. The flocs to be recovered or collected includes an aggregation of matters floating on a fluid, like magnetic substance such as magnetite and bio-plankton and microplastic. In addition, the invented device has an effect for solving the marine pollution problem by breaking and recovering plastics floating in the ocean using a slit, and further by recovering microplastic that cannot be broken by the slit by flocculation and magnetic separation. In addition, the marine pollution can be efficiently removed by determining the ship course to a sea area where a large quantity of plastics are floating using satellite information and collecting marine plastic in such sea areas where amounts of marine plastics are floating. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  This figure is a side view of an example of a configuration diagram of the magnetic separating section of the flocculation and magnetic separation device of the present invention. 
         FIG. 2  This figure is a side view of an example of a configuration diagram of a separating section in a flocculation magnetic device of the present invention which device employs one fluid acceleration drum and one magnetic drum of the present invention. 
         FIG. 3  This figure is a side view of an example of a configuration diagram of the magnetic separating section of the flocculation magnetic device of the present invention which device employs two magnetic drums. 
         FIG. 4  This figure shows an example of a floc recovery section in the flocculation and magnetic separation device of the present invention. 
         FIG. 5  This figure shows an example of the configuration diagram of the flocculation and magnetic separation device of the present invention. 
         FIG. 6  This figure shows an example of the slit mechanism of the present invention for breaking plastics floating in the sea. 
         FIG. 7  This figure shows an example of the slit in a slitting mechanism of the present invention for breaking plastics floating in the sea. 
         FIG. 8  This figure shows an example of the marine plastic recovery system of the present invention. 
         FIG. 9  This figure shows an example of the marine plastic, microplastic, and ballast water purification system of the present invention. 
         FIG. 10  The figure shows an embodiment example of the operation of a ship equipped with the system for purifying marine plastic, microplastic, and ballast water. 
         FIG. 11  This figure is a side view of an example of a configuration diagram of the magnetic separating section of the flocculation and magnetic separation device of the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. 
     EXAMPLES 
       FIG. 1  shows an embodiment example of a magnetic separating section of the flocculation and magnetic separation device of the present invention. A magnetic drum  1  having magnets near the surface thereof and flocs  4 , containing a magnetic substance such as magnetite, on the flow  8   a  from the flocculation section, which is not shown in the figure, flow toward the drum  1  in the ascending direction opposite direction to the gravity direction  99 . A flow velocity distribution  3   a  in a flow  8   a  has the highest flow velocity about or at the center and the slowest flow velocity on the wall of the flow channel. Therefore, the flocs collect in the portion of the flow where its velocity is high and its pressure is low in accordance with Bernoulli&#39;s equation. In order to prevent the fluid in front of the magnetic drum  1  from separating off from a bump-like protrusion  5   a , the direction of the flow is changed by about 180 degrees or so at the bump-like protrusion  5   a  having a predetermined curvature. At that time, the flow in the vicinity of the bump-like protrusion  5   a  flows along a curved wall  6   b , because the height of the bump-like protrusion  5   a  is lower than the maximum height of a wall  6   a  that forms one wall of the flow channel. The flock  4  rises and becomes a flock  4   a  carried on a flow close to the surface of the liquid of the flow of the bump-like protrusion  5   a , and flows toward the magnetic drum  1 . Since the direction of rotation of the magnetic drum  1  is opposite to that of a fluid flow  3   b , fine eddies  10  are created, and the eddies  10  cancels out the velocity of the fluid, causing the floc  4   a  to float on the surface of the water with almost zero velocity. The flocs  4   a  on the surface of the water is attracted by the magnetic force of the magnet of the magnetic drum  1 , and move closer to the magnetic drum  1 , and sticks on the magnetic drum  1  by magnetic force. When the flocs  4   a  on the water surface are attracted to the magnetic drum  1  by magnetic force and pulled up from the water surface, the forces acting on the flocs are surface tension and magnetic force. Since the surface tension is a weak force, the flocs  4   a  are not broken. The magnetic drum  1  rotates in an opposite direction  2  to the flow direction of the flow  3   b , the flocs  4   b  on the drum are, therefore, separated immediately from the fluid. Therefore, the area of the magnetic drum  1  required for the magnetic drum  1  to separate magnetically the flocs  4   a  is small. 
     Therefore, the magnetic drum  1  can be downsized because there is no need to take into account the travel time until the floc  4   a  defies the fluid resistance and adheres to the magnetic drum  1  by magnetic force. The floc  4   b  moves with the rotation of the magnetic drum  1  and collides with a scraper  9 . Flocs  4   c  on the magnetic drum  1  are peeled off from the magnetic drum  1  by the scraper  9  pressed against the magnetic drum  1 , and a brush roller  7  rotating in a direction  7   b  opposite to a rotating direction  2 . The scraper  9  is supported in slant from a higher position to a lower position. Therefore, flocs  4   d  that have moved from the magnetic drum  1  onto the scraper  9  move on the scraper  9  by gravity and are recovered in the free-falling as flocs  4   e . As shown with the flow  3   b , the treated water, from which flocs have been removed from the fluid, flow through the flow channel formed by the magnetic drum  1  and a wall  6   b , and then the direction of the flow is changed by 180 degrees or so at a bump-like protrusion  5   b . The treated water falls freely with a velocity distribution  3   c  and is discharged as a flow  8   b . Further, the flocs  4   e  are discharged as a flow  8   c . The flow velocity in the area between the bump-like protrusion  5   b  and the magnetic drum  1  is slow and close to zero. Therefore, even if flocs  4  that were not removed in the vicinity of the bump-like protrusion  5   a  are present, they are attracted to the magnetic drum  1  in the vicinity of the bump-like protrusion  5   b  and are removed from the treated water. 
       FIG. 2  shows an embodiment example of the separating section of a flocculation and magnetic separation device using a rotating drum  11   a  that gives a flow velocity to the fluid and one magnetic drum  11   b . The non-magnetic rotating drum  11   a  rotates in a direction  12   a  same as a flow  18   a  which includes flocs  14  and rotates at the rotation speed such that the peripheral speed thereof is at least equal to or higher than the average speed of a flow velocity. By forcibly increasing the flow velocity on the surface as in the Couette Flow, there is an effect that the portion of the flow having the highest flow velocity is brought closer to the vicinity of the rotating drum  11   a . The purpose of this is to increase the probability that the flocs will collect in a place where the flow velocity is high, that is, where the pressure is low, and that the flocs will be carried by a flow flowing to a magnetic drum  12   b  that is located at the subsequent stage and rotates in the opposite direction. From the flocculation area, which is not shown in the figure, the fluid including flocs flows toward the rotating drum  11   a  rotating in the direction  18   a , which is opposite to the direction of gravity  99 . As shown in a velocity distribution  13   a  in the fluid, the velocity is fastest about in the center of the flow channel. The flocs  14 , therefore, collect in the center of the flow. The direction of the flow is changed by 180 degrees or so at a bump-like projection  15   a  having a predetermined curvature. In a vicinity  13   b  of the bump-like protrusion  15   a , the rotational force of the rotating drum  11   a  increases the speed of the flow. Therefore, the flow containing the flocs does not stay in the vicinity of the rotating drum  11   a  but flows toward a wall  16   a . The high-velocity part of the flow  13   b  in the flow channel formed by the rotating drum  11   a  and the wall  16   a  is closer to the rotating drum  11   a  than when the drum  11   a  is not rotating. This is attributable to the peripheral velocity of the rotating drum  11   a . Therefore, in a flow  13   d  in the vicinity of a bump-like protrusion  15   b  with curvature, the flow velocity is the highest at the part near the periphery. Flocs  14   c  collects in such a high flow velocity part and heads toward the magnetic drum  11   b . In the vicinity of the magnetic drum  11   b , there is a stagnant basin where the flow velocity is slowed down to almost zero by eddies  20   b . Due to this almost-zero velocity, flocs  14   b  are attracted to the magnetic drum  11   a  rotating in the rotational direction  12   a  and are moved then released from the magnetic drum  11   b  by a slant-installed scraper  19  and a brush roller  17   a  which rotates in a rotational direction  17   b  opposite to a rotational direction  12   b . The scraper  19  is supported in slant from a higher position to a lower position. Therefore, the flocs that have moved from the magnetic drum  11   b  onto the scraper  19  move on the scraper  19  by gravity and are recovered by free-falling as flocs  14   e . The treated water from which the flocs have been removed flows around the magnetic drum  11   b , and the direction of flow is changed by about 180 degrees or so at a bump-like protrusion  15   c  and is discharged by the gravity as a flow  18   b  with a velocity distribution  13   e . Flocs  14   e  is also discharged as a flow  18   c.    
       FIG. 3  shows an embodiment example of the present invention, which example is the magnetic separating section of the flocculation and magnetic separation device using two magnetic drums. The device of the present invention comprises a first magnetic drum  21   a  and a second magnetic drum  21   b  arranged front and back each other. The first magnetic drum  21   a  rotates in a direction  22   a  opposite to the direction of the flow that includes flocs and the second magnetic drum  21   b  rotates in a direction  22   b  the same as the flow that includes flocs. The flocculating section, though not shown in the figure, produces a flock-contained fluid by flocculating floating matters in a fluid together with magnetic substances such as magnetite. A flock-contained fluid flows out from the flocculation section, carried on a flow  28   a , of which flow direction is opposite to the gravity direction  99 , and heads toward the first magnetic drum  21   a  beyond a bump-like protrusion  25   a . The flow  28   a  has the highest flow velocity about or at its center and the slow flow velocity in the vicinity of the wall  26   c  of the flow channel. Therefore, the flocs collect in the portion of the flow where its velocity is high and its pressure is low according to Bernoulli&#39;s equation and the distribution of velocity forms as shown with a velocity distribution  23   a . In order to prevent the fluid from separating at a bump-like protrusion  5   a  provided at the front of the magnetic drum  1 , the direction of the flow is changed by about 180 degrees or so at that bump-like protrusion  5   a  having a predetermined curvature. Like the velocity distribution  23   a , the velocity in the fluid is fastest in the center of the flow channel; the flocks  24 , therefore, collect in the center of the flow. At the time when the direction of the flow is changed largely by 180 degrees or so at the bump-like projection  25   a  having a predetermined curvature, the flow velocity in the outer circumference reaches the fastest, therefore, the flocks  24  move to the flocs  24   a  carried on a flow in the vicinity of the fluid surface, and the flocks  24   a  head the magnetic drum  21   a , carried on a flow flowing toward the magnetic drum  21   a . And further are attracted to the magnetic drum  21   a  by the magnetic force of the magnet on the surface thereof. Flocs  24   b , which are attracted to the surface of the magnetic drum  21   a  by magnetic force, attach on the magnetic drum  21   a  rotating in the rotation direction  22   a . Flocs  24   b , which are attracted to the surface of the magnetic drum  21   a  by magnetic force, attach on the magnetic drum  21   a  rotating in the rotation direction  22   a . Then the flocs  24   b  so attached to the magnetic drum  21   a  are separated therefrom by a scraper  29   a , which is pressure-contacted to the magnetic drum  21   a , and by a brush  27   a . Being separated, the flocs  24   c  move on the scraper  29   a  and recovered into a floc recovering section  30 . Since the direction of rotation of the magnetic drum  21   a  and the fluid flowing in the flow channel between the magnetic drum  21   a  and a curved wall  26   a  of the flow channel are opposite in velocity direction, eddies are generated in the fluid. The eddies cause the flocs to adhere to the magnetic drum. In this instance, however, the rotation speed of the magnetic drum  21   a  needs to be low enough that the eddies do not break the flocs, and the rotation speed is controlled considering the flocculation state. The flow direction of the fluid is greatly changed by a bump-like protrusion  25   b , resulting in the movement of flogs toward the magnetic drum  21   b , and the magnetic force causes the flocs  24   d  to attach to the magnetic drum  21   b . Since the flow direction of the fluid and the rotation direction of the magnetic drum  21   b  is the same, there imposed no shearing or other force from the fluid, therefore the floc  24   d  on the surface of the magnetic drum  21   b  will not be separated by the fluid. The magnetic drum  21   b  rotates in the direction of rotation  22   b , and the floc  24   d  on the magnetic drum  21   b  is scraped off by a scraper  29   b  which is in pressure-contact and by a brush  27   b . The scraped flocs are then collected in the floc collection section  30 , as shown with the flocs  24   c . In the present invention, the floc collection section  30  can be integrated into one, so that the cost can be reduced. Instead of using the magnetic drum  21   b , a filter separation method, as shown in  FIG. 8 , may be used. In the filter separation method, the same effect can be achieved by using a filter mesh of 47 microns or less so as to meet the removal standards for ballast water purification systems. 
       FIG. 4  shows an embodiment example of the floc recovery section in the flocculation and magnetic separation device of the present invention. A recovery section  34  consists mainly of a magnetic drum  31 , a scraper  37  pressed against thereto, and a brush roller  36  used to peel off the flocs attracted by magnetic force on the surface of a magnetic drum  31 . The flocs moved from the magnetic drum  31  by the brush roller  36  onto the scraper  37  are moved further by gravity and collected in the floc recovery section  34 . Since the floc recovery section  34  is arranged in slant, the flocs move by gravity and are discharged from the end of the floc recovery section  34 . The floc recovery section  34  has a semi-cylindrical shape to collect the flocs, but a concave or inverted triangular cross-section is also acceptable. 
       FIG. 5  shows an example of the embodiment configuration of the flocculation and magnetic separation device. In this configuration, a fluid  59  flows into a flocculation and magnetic separation device  55 , and the appropriate amount of flocculant from a flocculant storage tank  40  and the appropriate amount of magnetite from a magnetite solution storage tank  41  are fed into the device, which is then agitated by a stirrer  43  in a quick stirrer unit  42  to produce micro-flocs. Inorganic flocculant and magnetite can be fed in any order and may be fed at the same time. Then, an organic flocculant  46  such as a polymer is added and agitated by a stirrer  45  in a slow-speed stirrer  44  to produce flocs in a size of several hundred microns to several millimeters. The flocs enter the separating section, and the fluid including flocs, of which speed has been increased by the rotational force of a non-magnetic rotating drum  49 , head to a magnetic drum  50 . The floc attaching to the surface of the magnetic drum is scraped from the surface thereof by a scraper  52  and a brush roller  51  that are in press-contact with the surface of the magnetic drum. Plankton and micro-flocs in the fluid  59  are flocculated and become flocs, which are removed from the fluid by the magnetic drum  50  described above. A separation section may be the separation section shown in above-stated  FIG. 3 . 
       FIG. 6  shows an example of the slitting mechanism for breaking plastics floating in the ocean. When plastics drifting in the sea is taken in by a ballast pump together with ballast water, seawater  63  is sucked also into a pipe  60  by the ballast pump, which is not shown in the figure. A first slit section  61  is arranged at a predetermined angle  611  with respect to the fluid to be sucked. A second slit section  62  is arranged at the rear stage of the first slit section  61  at a predetermined angle  622 , which is different from the angle  611 , with respect to the fluid to be sucked. The reason that the angle  611  is an acute angle and the complementary angle of the angle  622  is an obtuse angle in relation to the sucking direction of seawater  63  is to prevent clogging between the slit  61  and the slit  62  caused by drifting plastics. The slits are placed at a predetermined angle with respect to the inflow direction so that the shearing force can work. 
       FIG. 7  shows an embodiment example of the slit section of a slitting mechanism that breaks plastics floating in the ocean. A slit section  61  of a pipe  60  comprises plates  61   a ,  61   b , and  61   c  each for forming slits thereon, as shown in  FIG. 6 . A slit section  62  shown in  FIG. 6  comprises plates  62   a ,  62   b , and  62   c  each for forming slits thereon. The cross-section of the plates  61   a ,  61   b ,  61   c ,  62   a ,  62   b , and  62   c  are acute angles  61   x  and  65   x  with respect to the inflow direction. The reason for being the acute angle is to break the inflowing plastic. The plates  61   a ,  61   b ,  61   c ,  62   a ,  62   b ,  62   c  are arranged at equal intervals of  65   a .  65   b ,  65   c , and  65   d . However, considering that the flow rate of the middle part is the maximum, spacings wider than the intervals  65   b  and  65   c  can be given to the plates  65   a  and  65   d . With this, the effect for reducing the probability that the plastic waste may clog the slits will be produced. 
       FIG. 8  shows an embodiment example of the broken plastic recovery mechanism of the present invention. A fluid  73  such as seawater that includes a plastic  77  broken by the slit mechanism mentioned before flows in through a pipe  72 . An endless belt filter  70 , consisting of a filter of predetermined mesh size, rotates continuously between the rollers  71   a  and  71   b , and the fluid  73  containing the broken plastics  77  passes between the rollers  71   a  and  71   b . While passing, the endless belt filter  70  holds and conveys the broken plastics  77 , which is then separated by a scraper  75  press-contacted on the endless belt filter  70 , and the separated broken plastics  77  are put in a floe recovery tank  76 . Further, the fluid  73  from which the broken plastics  77  has been removed flows into a pipe  74 . The fluid  73  contains fine floating matter such as microplastics and plankton. The fluid  73  is sent to the flocculation and magnetic separation device  55  described above and undergoes flocculation and magnetic separation to become the fluid  59 . In some cases, this recovery mechanism is installed at the rear stage of the magnetic separation mechanism to filter the objects that cannot be magnetically separated. 
       FIG. 9  shows an embodiment example of the marine plastic, microplastic, and ballast water purification system of the present invention. The marine plastic, microplastic, and ballast water purification system  100  is a system that is equipped on a ship. 
     The system comprises:
         a slitting mechanism  101  for breaking plastics,   a pump  102  for supplying and draining seawater or freshwater,   a recovering mechanism  103  for recovering large floating matters of tens of mm or more such as broken plastics,   a recovery tank  104  for temporarily storing the recovered floating matters,   a flocculation and magnetic separation mechanism  105  for recovering small floating matters of less than tens of mm, such as microplastics and plankton,   a recovery tank  106  for temporally storing removed flocs that include microplastics or the like, and   a control mechanism  108 .       

     The flocculation and magnetic separation device  105  can be a composite mechanism that is a combination of a filter such as a ceramic filter and ozone or ultraviolet light. The treated water is temporarily stored in a ballast tank  107 . 
       FIG. 10  shows an embodiment example of the operation method of the marine plastics, microplastics, and ballast water purification system. 
     A course plan information center  210  is configured with:
         a means for acquiring marine traffic information  202 ,   a means for collecting marine plastic information  203 ,   a means for collecting geographic information  204 ,   a means for creating planned course  295 .   a means for receiving planned course request  201 , and   a means for providing planned course  206 .       

     The means for acquiring marine traffic information  202  gathers the information of the automatic vessel identification system and other similar information collected from the base stations not illustrated in the figure. The means for collecting marine plastic information  203  collects information on the pollution caused by marine plastics in the sea area of which state is gathered by a satellite  200 . The means for acquiring geographic information  202  acquires the location of own ship, the port of destination, and the geographic information on the sea area between these two places included in the planned course request signal. A means for creating planned course  205  produces a planned course based on the information collected by the means for acquiring regional traffic information  202  mentioned above, the means for collecting marine plastics and other marine pollution information  203 , and the means for collecting geographic information  204 . When creating this planned course, the plan will take into account whether the ballast water is loaded, how much are the quantity of loaded ballast water when loaded, whether the removal work of ocean plastics and other marine pollution matters can be performed, and the urgency of the ocean plastics removal work. A ship  220  is equipped with a means for transmitting the planned course request  221 , a means for receiving the planned course  222 , and a steering means  223  that operates reflecting the received results. The results of the removal work for marine plastics and other marine pollution matters (removed marine area, amount of removed marine plastics, and other marine pollution matters) are transmitted to the course plan information center  210 . The course plan information center transmits this information to the International Maritime Organization (IMO) and other public organizations, and environmental protection groups. International organizations, such as the International Maritime Organization, and environmental protection groups will make this information available to the public and formulate strategies against marine pollution. As a result, if further removal of pollution is necessary, cooperation will be asked ships that are scheduled to sail near the area in question for taking measures against marine pollution. The collected marine plastics and other marine pollutants will be purchased by the government or municipality of the port of call as industrial waste. This means that the ships equipped with marine plastics, microplastics, and ballast water purification systems will take the charge of cleaning the ocean in addition to transporting oil and other valuable materials. 
       FIG. 11  shows an embodiment example of the magnetic separating section of the flocculation and magnetic separation device of the present invention. A magnetic drum  301  having magnets near the surface thereof, and flocs  304  on a flow  308   a  from a flocculation section, which is not shown in the figure, containing magnetite and other magnetic substances flow in the direction opposite to the direction of gravity  99  toward the magnetic drum  301 . The velocity distribution  303   a  in the flow  308   a  has the highest velocity almost at the middle and the low velocity at the wall of the flow channel. Therefore, the flocs gather in the center of the flow where the velocity is faster according to Bernoulli&#39;s law (Bernoulli&#39;s equation). In order to move the flocs  304  flowing in the middle of the fluid in the immediate front of the magnetic drum  301  to the fluid surface, the direction of flow is changed by about 180 degrees or so at a bump-like projection  305   a  having a predetermined curvature, and the fluid flows along a concave  305   a  having a predetermined curvature placed at the subsequent stage. This concave  305   b  and a bump-like protrusion  305   c  configure a waterfall-basin-like structure, which produces eddies  310   a . Since the particle size of a floc  304   b  is larger compared to that of a fluid molecule, this size difference produces fluid resistance, which causes the eddies  310   a . The eddies  310   a  make the flocs  304   b  float on the fluid surface. The flocs flow towards the magnetic drum  301 . Since the direction of rotation of the magnetic drum  301  is opposite to that of a fluid flow  303   b , this direction difference creates eddies  310   b , and the velocity of the fluid in the eddies  310   b  cancels each other, resulting in a lower velocity of flocs  4   a . Flocs  304   a  on the flow of low-velocity approach a magnetic drum  1  by the magnetic force and attracted thereon. Since the resistance acting on the flocs  304   a  is mainly surface tension, the flocs  304   a  are not easily broken. The magnetic drum  301  rotates in a direction  302  opposite to the flow  303   b , so that the floc  304   b  on the drum is immediately separated from the water. Therefore, the contact area of the magnetic drum  301  required for separating magnetically the flocs  304   a  can be reduced to an extent several mm above and below the fluid surface. The reason for this is that when the flocs  304  are attracted to the magnetic drum  301 , a new surface with no flocs attracted appears since the magnetic drum  301  is rotating. Therefore, the actual contact area on a magnetic drum  301  required for attracting flocs thereto by the magnetic force of the magnetic drum  301  is small. The magnetic drum  1  is not damaged by the fluid resistance. Furthermore, it is not necessary to consider the travel time of the flocks to adhere, by the magnetic force, to the magnetic drum  1  against the fluid resistance, as described in {Patent Literature 1}. Therefore, the magnetic drum  301  can be miniaturized. Flocs  304   c  on the magnetic drum  301  is separated therefrom by a scraper  309  pressed against the magnetic drum  301  and the brush roller  307  rotating in a rotation direction  307   a  opposite to the rotation direction  302 , and the flocs  304   b  move onto the scraper  309 . The flocs  304   b  are recovered by free fall due to gravity like flocs  304   d . Further, the treated water from which the flocs have been removed flows along the magnetic drum  301  as shown in the flow  303   b , and the direction of the flow is changed by about 180 degrees or so at the bump-like protrusion  305   c . The treated water flows with a flow velocity distribution  303   c  and is discharged as a flow Sb. Further, the flocs  4   c  are discharged as a flow  308   c.    
     INDUSTRIAL APPLICABILITY 
     The International Maritime Organization (IMO) established the Convention for the Control and Management of Ships&#39; Ballast Water and Sediments (hereinafter referred to as the Convention) in order to prevent the destruction of ecosystems caused by seawater substitution by ships&#39; ballast water which includes species that did not originally exist in the sea area. However, the problem of ocean pollution by plastics and microplastics has arisen. The mainstream of ballast water treatment method is a sterilization method using ultraviolet rays, ozone, hypochlorous acid, or the like. This method can kill aquatic organisms in ballast water. However, the problem of marine pollution caused by the above-stated plastics and microplastics cannot be solved. Even a ship that collects marine plastics is built, it is still difficult to recover microplastics, though such a ship can recover large plastics. The present invention provides a method for simultaneous solving the problem of ecosystem destruction caused by ballast water and the problem of marine pollution caused by plastics and microplastics. 
     
       
         
           
               
             
               
                   
               
               
                 {Reference Signs List} 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
            
               
                 1, 11b, 22a, 22b, 
                 Magnetic drum 
               
               
                 31, 50, 301 
               
               
                 2, 12a, 12b, 22a, 
                 Direction of rotation 
               
               
                 22b, 78, 302 
               
               
                 3a, 3c, 13a, 13b, 
                 Flow velocity distribution 
               
               
                 23a, 23b, 303a, 303b 
               
               
                   3b 
                 Direction of flow 
               
               
                 4, 14, 304 
                 Flocs 
               
               
                 4a, 14a, 14c, 
                 Flocs flowing toward magnetic drum 
               
               
                 24a, 304a 
               
               
                 4b, 14d, 24b, 
                 Flocs attracted on magnetic drum 
               
               
                 24d, 304c 
               
               
                 4c, 14e, 14f, 24c 
                 Recovered flocs 
               
               
                 5a, 5b, 15a, 15b, 
                 Bump-like protrusion 
               
               
                 15c, 25a, 25b, 25c 
               
               
                 6a, 6b, 16a, 16b 
                 Wall surface 
               
               
                 7, 17a, 17d, 27a, 
                 Brush roller 
               
               
                 27b, 51, 307 
               
               
                 7a, 17b, 17c 
                 Brash roller rotation direction 
               
               
                 7a, 17b, 17c 
                 Flow direction of fluid including flocs 
               
               
                 8b, 18b, 28b 
                 Flow direction of treated fluid 
               
               
                 8c, 18c, 18d 
                 Flow direction of recovered flocs 
               
               
                 9, 19a, 19b, 29a, 
                 Scraper 
               
               
                 29b, 37, 52 
               
               
                 11a, 49  
                 Rotating drum 
               
               
                  34 
                 Flocs recovery section 
               
               
                  40 
                 Flocculant storage tank 
               
               
                  41 
                 Magnetite storage tank 
               
               
                  42 
                 Slow stirring device 
               
               
                  44 
                 Quick stirrer 
               
               
                 43, 44 
                 Stirrer 
               
               
                  46 
                 Polymer storage tank 
               
               
                 59, 63, 73 
                 Fluid 
               
               
                 60, 72, 74 
                 Pipe 
               
               
                 61, 61a, 61b, 61c, 
                 Plate for forming slit 
               
               
                 62, 62a, 62b, 62c 
               
               
                 61x, 65x 
                 Cross section of plate 
               
               
                 65a, 65b, 65c, 65d 
                 Plate spacing 
               
               
                  70 
                 Endless belt filter 
               
               
                 71a, 71b 
                 Roller 
               
               
                  76 
                 Flocs recovery tank 
               
               
                 100 
                 Marine plastics, microplastics and ballast water 
               
               
                   
                 purification systems 
               
               
                 101 
                 Filtering mechanism 
               
               
                 102 
                 Pump 
               
               
                 103 
                 Recovering mechanism 
               
               
                 104, 106 
                 Recovery tank 
               
               
                 105 
                 Flocculation and magnetic separation 
               
               
                   
                 mechanism 
               
               
                 107 
                 Ballast tank 
               
               
                 108 
                 Control console 
               
               
                 200 
                 Satellite 
               
               
                 210 
                 Course plan information center 
               
               
                 201 
                 Means for receiving planned course request 
               
               
                 202 
                 Means for collecting marine traffic information 
               
               
                 203 
                 Means for collecting information on marine 
               
               
                   
                 pollution such as marine plastics 
               
               
                 204 
                 Means for collecting geographical information 
               
               
                 205 
                 Means for creating planned course 
               
               
                 206 
                 Means for providing planned course 
               
               
                 210 
                 Ships 
               
               
                 221 
                 Means for transmitting planned course request 
               
               
                 222 
                 Means for receiving planned course 
               
               
                 223 
                 Steering means 
               
               
                  305a 
                 Concave