KR101779119B1 - Ballast water treatment system and method - Google Patents

Abstract

The present invention provides a system and a method for treating ballast water. The method for treating ballast water is performed in the system for treating ballast water inputted to a ballast water tank of a ship. The system for treating ballast water comprises: a centrifugal separator separating foreign matters from the ballast water by using difference in specific gravity; a micro bubble generating apparatus connected to a rear end of the centrifugal separator and generating micro bubbles into the ballast water inputted from the centrifugal separator; a filtering apparatus connected to the micro bubble generating apparatus and including a separator made of a ceramic material to filter the ballast water with the micro bubbles inputted therein; and an ultraviolet sterilizer having one side connected to the filtering apparatus and the other side connected to the ballast water tank and irradiating ultraviolet rays to sterilize the ballast water inputted therein. The separator, in which an accommodation space where the ballast water is accommodated is provided, is formed in a disk shape to be able to rotate, and has a pore diameter whose size ranges from 2 to 10 m.

Description

Technical Field [0001] The present invention relates to a ballast water treatment system and method,

The present invention relates to a ship ballast water treatment system and method, and more particularly, to a ship ballast water treatment system and method for treating and storing a large amount of ship ballast water in a short time.

Ship ballast water refers to the water that flows into the ballast water tank of the ship or discharges to the sea in order to balance and balance the center of gravity of the ship in the process of loading and unloading the ship or in the ballast state, It is estimated that more than 10 billion tons are moving around the world.

However, since water in a specific sea area contains a large number of organisms or pathogens, harmful substances such as pathogens are moved to other sea areas by vessels containing equilibrium water, disturbing the environment and ecosystem of the water area, Or commercial activities.

Currently, the United Nations International Maritime Organization (IMO) sees more than 7,000 marine species moving from one vessel to another via ship equilibrium for a year. Many of them die because they can not adapt to the new environment, but mussel-like creatures that survive will survive and disturb the ecosystem and cause a lot of damage. There are cholera, daphnia, crab, poisonous birds, whales, European melon, Asian kelp, spotted mussels, North Pacific starfish, and North American jellyfish that are moving into the ballast water balloon selected by the International Maritime Organization. The influx of exogenous species suggests that US aquatic biophysical research institutes will have $ 134 billion in damage by 2050.

In order to prevent side effects such as disturbance of the ecosystem caused by ship ballast water, the International Maritime Organization decided to mandate ship equilibrium water treatment facilities for vessels of all over the world, and in February 2004 the ship's ballast water and sediment The International Convention for the Control and Management of Biological Diversity. This Convention prohibits the unauthorized discharge of ballast water in order to reduce the movement of foreign organisms and specifies the discharge conditions of ship ballast water. Therefore, ships carrying international voyages must have a variety of disinfection devices to kill creatures in order to meet ballast water discharge requirements. As the conditions for the entry into force of the Convention (30 countries, 35% of the fleet) will be fulfilled in September 2016, it will be enforced within five years from September 2017, one year from this, and the facilities approved by the International Maritime Organization There are 40 locations (as of September 2016) and there are 15 domestic companies and 38 facilities under USCG approval.

In order to meet the emissions standards of these international conventions, various systems have been proposed to treat ship ballast water in ships. The method of water treatment of ship equilibrium water is divided into physical treatment and chemical treatment. The physical treatment includes filtration, centrifugation, ultraviolet irradiation, heat treatment using heat, ultrasonic irradiation, etc. Generally, the chemical treatment involves generating chemicals such as electrolysis, chlorine, chlorine dioxide, ozone, hydrogen peroxide, .

Conventional systems for treating ship ballast water include a device that includes a micro-separating membrane made of an organic film and filters the whole amount by a filtration method, an apparatus for sterilizing and removing various malignant microorganisms by an ultrasonic sterilizer or an ultraviolet sterilizer.

However, according to the conventional system for treating ship equilibrium water, there is a problem that a large amount of washing water is required due to a short backwash cycle of the separation membrane and the backwash efficiency is lowered. Further, since a disinfectant is used to increase the backwash efficiency, there is a problem that the filtration efficiency is lowered and a large amount of chemical waste liquid is generated.

Further, there is a problem that the inter-membrane pressure difference is increased due to a clogging phenomenon caused by the accumulation of contaminants on the surface of the separation membrane used in the filtration apparatus. In the case of a conventional filtration apparatus using a separation membrane, since a backwash water tank is required for backwashing the separation membrane, there is a problem that the required site is increased and secondary pollution occurs in the discharge area due to the disinfectant for disinfecting the water tank .

The present invention provides a ship ballast water treatment system and method for enhancing disinfection and filtration efficiency of ballast water through a ceramic membrane with a microbubble applied thereto.

The present invention also provides a ship ballast water treatment system and method for preventing the accumulation of contaminants on the surface of the separation membrane, minimizing the differential pressure rise of the separation membrane, and improving the filtration performance, thereby treating large amounts of seawater in a short time.

The present invention also provides a ship ballast water treatment system and method for improving the recovery rate of the separation membrane in the backwash stage and improving the backwash efficiency.

A ship ballast water treatment system according to the present invention is a ship ballast water treatment system for treating a ballast water flowing into a ballast water tank of a ship, comprising: a centrifugal separator for separating foreign matter from the ballast water by using a specific gravity difference; A micro bubble generator connected to a rear end of the centrifugal separator and generating micro bubbles in the ballast water introduced from the centrifugal separator; and a separator membrane of ceramic material connected to the micro bubble generator, The ballast water tank is connected to the filtration unit. The ballast water tank is connected to the ballast water tank. The ballast water tank is irradiated with ultraviolet rays to sterilize the ballast water flowing into the ballast water tank. And a sterilizing device, wherein the separation membrane is provided with a receiving space in which the ballast water is received, The separator is provided in the shape of a disc and is rotatably provided, and the size of the gap provided in the separator is in the range of 2 to 10 mu m.

According to another aspect of the present invention, there is provided a ship ballast water treatment method for treating a ballast water flowing into a ballast water tank of a ship, the method comprising: a storage step of storing the ballast water in the ballast water tank; And a discharging step of discharging the ballast water stored through the storing step to the outside from the ballast water tank, wherein the storing step includes: a separating step of separating foreign matter by flowing the inflowed ballast water into a centrifugal separator; A micro bubble generating step of flowing the ballast in which the foreign substance is separated in the separation step into the micro bubble generating device to generate micro bubbles in the ballast water; Water is introduced into a filtration device connected to the micro bubble generator, and a ceramic And a filtration step of filtering the equilibrium water by a separation membrane. When a predetermined time has elapsed after the filtration step is started or when the pressure difference between the inside and the outside of the separation membrane reaches a predetermined range, And the backwashing step of supplying the water to the filtration apparatus and backwashing the filtration apparatus, wherein the backwashing step permeates the ballast water supplied from the ballast water tank from the inside to the outside of the separation membrane, And a first cleaning step of removing contaminants from the surface of the substrate, wherein the back washing step includes, when a predetermined time elapses after the start of the first cleaning step, Water is introduced into the filtration apparatus through the micro-bubble generator, whereby the micro-bubble contained in the ballast water Further comprising a second cleaning step of removing contaminants on the surface of the separation membrane.

The system and method for treating ship ballast water according to the present invention can increase the disinfection and filtration efficiency of the ballast water through the ceramic material separator using micro bubbles, It can be stored in the ballast water tank or discharged to the sea area in accordance with the regulations.

Further, according to the present invention, since the storing step of the ballast water, the backwashing step, and the discharging step can all be performed by one processing system, the required site for the ballast water treatment is reduced and the processing cost is reduced . Then, each device is connected by a pipe, and since there is no storage tank at each stage, secondary contamination by microorganisms can be prevented.

According to the present invention, since the accumulation of contaminants on the surface of the separation membrane is prevented, the differential pressure of the separation membrane can be prevented from rising and the filtration time of the separation membrane can be maintained for a long time and the flux as the membrane filtration flow rate per unit area can be increased . Accordingly, despite the separation membrane to which the cross-flow filtration system is applied, high flux can be realized similarly to the full-volume filtration system, so that an excellent effect of processing and storing a large amount of seawater in a short time can be obtained.

Further, according to the present invention, there is no need to add a disinfecting agent in the backwashing step, and there is no need to inject air separately at the time of backwashing. Further, by circulating the ballast water to the surface of the separation membrane and reusing the effluent water as backwash water, the recovery rate of the separation membrane can be improved. In addition, by using micro bubbles in the backwashing step, contaminants that have not been removed by reverse osmosis can be desorbed, thereby enhancing the removal efficiency of contaminants in the separation membrane.

1 is a block diagram illustrating a ship ballast water treatment system and a storage step using the same according to an embodiment of the present invention.
2 is a flow chart showing a storage step of the ship ballast water treatment method according to the present invention.
3 is a block diagram showing the backwashing step of the ship ballast water treatment method according to the present invention.
4 is a block diagram showing the discharge step of the ship ballast water treatment method according to the present invention.
5 is a cross-sectional view showing a filtration apparatus applied to an embodiment of the present invention.
6 is a partially cutaway perspective view of a separation membrane according to an embodiment of the present invention.
FIG. 7 is a graph showing the turbidity and turbidity removal rate in the experimental example using the centrifugal separator and the filtration apparatus according to the present invention. FIG.
8 is a graph showing filtration performance depending on the type of separation membrane applied to the filtration apparatus.
9 is a graph showing a cost reduction according to the type of separation membrane applied to the filtration apparatus.
10 is a graph comparing the filtration speed and the intermembral pressure correction differential pressure according to the type of the filtration device.
11 is a graph showing a change in the intermuscular correction pressure difference and a correction differential pressure in the future depending on the type of the filtration device.
FIG. 12 is a graph showing the turbidity of the water discharged from the concentrated water when the microbubbles are not applied to the filtration apparatus and when the microbubbles are applied, in the backwashing step according to the present invention.
13 is a graph showing the recovery rate depending on the type of the filtration apparatus.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, the embodiments described below are embodiments suitable for understanding the technical characteristics of the ship ballast water treatment system and method of the present invention. However, the technical features of the present invention are not limited by the embodiments to which the present invention is applied or explained in the following embodiments, and various modifications are possible within the technical scope of the present invention.

The ship ballast water treatment system 100 and method according to an embodiment of the present invention is based on treating the ballast water flowing into the ballast water tank 600 of the ship. Specifically, the ballast water supplied from the raw water such as seawater is treated and stored in the ballast water tank 600, and the ballast water stored in the ballast water tank 600 is discharged and processed so as to satisfy the ballast water discharge condition of the International Maritime Organization System and method.

1, a ship ballast water treatment system 100 and method according to an embodiment of the present invention includes a centrifugal separator 200, a micro bubble generator 300, a filtration apparatus 400, Device 500 as shown in FIG.

The centrifugal separator 200 can separate foreign matter from the ballast water using the difference in specific gravity. Specifically, the centrifugal separator 200 can remove particulate floating materials and some marine organisms due to the specific gravity difference due to the high flow rate of the centrifugal separation.

The centrifugal separator 200 is one of the hydraulic dynamical separators for separating particles by applying a centrifugal force to the particles and accelerating the sedimentation velocity, and is a gravitational settling apparatus. The centrifugal separation is a principle in which a fluid containing particles flows into a right angle in the tangent direction through a spiral inlet portion to generate a centrifugal force in the inside of the device and separates the particles at a high speed by using such centrifugal force. That is, it forms a vortex in a solid material to perform solid-liquid separation.

When raw water such as seawater flows into the centrifugal separator 200, the particles having a specific gravity larger than water hit the inner wall of the apparatus by centrifugal force and are discharged to the first discharge portion 31 provided at the lower portion of the apparatus. The released particles may be suspended solids and some marine organisms over a predetermined size. Particularly, some of species introduced into the centrifuge 200 together with seawater can be gravitationally sedimented due to the specific gravity difference because centrifugal separation can not exert mobility when a specific acceleration is applied. For example, when a gravitational acceleration of 1.05 to 1.1 times of the gravitational acceleration is applied, the grapevine bird can be separated from the ballast water and discharged to the sea area again.

The ballast water, which is the raw water from which the particles have been removed, rises up through the air bag in the center of the centrifugal separator 200 and can be discharged through the upper vortex finder. The rotary current outlet may be connected to the production water pipe 21 connected to the micro bubble generator 300.

There is no limitation on the type of the centrifugal separator 200, and various kinds of centrifugal separators 200 can be applied as long as they can remove floating substances and marine organisms having a predetermined size or more due to the specific gravity difference. For example, the centrifugal separator 200 may be a hydro cyclone, but is not limited thereto.

The micro bubble generator 300 is connected to the rear end of the centrifugal separator 200 and can generate micro bubbles in the ballast water flowing from the centrifugal separator 200.

Specifically, the micro bubble generator 300 can receive the ballast water separated by the centrifugal separator 200.

Micro bubbles collectively refer to ultrafine bubbles of about 50 μm or less, which is about 1/2 of the diameter of the hair. The micro bubbles have the characteristics of collapsing into a nano bubble having a predetermined size (for example, 10 μm or less) due to the internal contraction action, generating high-temperature and high-pressure ultrasonic waves and OH radicals, collapsing and disappearing. Microbubbles have a mass transfer coefficient a multiplied by a factor of 1 when the bubble diameter is reduced to 1 / a, at which time the bubble quantity increases to a ³ . In addition, when the unit volume is atomized to 1/10, the total surface area is increased ten-fold. As a result, the smaller the micro bubble size, the more the dissolution efficiency increases.

For example, when the size of the bubble is reduced to 1/10, the contact area with water increases by a factor of 10, so that the dissolution rate can be increased 100 times in theory when the size of the bubble of 1 mm is reduced to 1/100.

Also, in the micro bubble, a self-pressurizing phenomenon occurs in which the pressure increases in inverse proportion to the diameter of the fine bubbles. Specifically, the bubbles exist in the form of a spherical gas in water and are surrounded by the vapor-liquid interface, and the pressure inside the bubbles increases due to the physical action of the surface tension at the interface. For example, when the diameter is 10 탆, the pressure increases by about 0.3 atm and 1 탆 by about 3 atm. Since the amount of bubbles dissolved in the liquid under a certain temperature is dissolved in proportion to the partial pressure of the bubbles, the more the fine bubbles become, the higher the dissolving ability of the bubbles becomes, and in particular, the pressure of the bubbles at the moment of disappearing becomes theoretically infinite.

Due to this self-pressurizing phenomenon, the microbubbles are instantly destroyed by repeated high-temperature heating in a short time and by repeated chain reactions of compression and rupture. At this time, free radicals such as hydroxyl radicals (OH) are generated, and bacteria and toxic chemicals present in the inflowing equilibrium water can be decomposed.

The bubble generating method of the micro bubble generator 300 is not limited, and various methods can be applied. For example, the micro bubble generator 300 may be a turning system that generates micro bubbles by turning the ballast water. Specifically, when the liquid and the gas are mixed, the micro bubble generator 300 becomes a local vacuum state when the fluid passes through the small-diameter passage according to the Bernoulli's equation in the ejector. In this case, You can create bubbles.

Since the micro bubble generator 300 according to the pivoting method can perform an independent self-excitation, a large amount of micro bubbles can be generated with only a small amount of air. Thus, the power ratio is reduced.

However, the micro bubble generator 300 to which the present invention is applied is not limited to the above-described pivot system, and various modifications are possible. For example, a pressing type using a high-pressure pump, or a method of mixing a gear in a mixer form by attaching a gear to an impeller shaft may be applied.

The filtration unit 400 may be connected to the micro bubble generator 300 and may include a ceramic separator 420 to filter the equilibrium water containing micro bubbles flowing therein.

Specifically, the filtration apparatus 400 may include a separation membrane 420 made of a ceramic material. More specifically, the main body 421 included in the separation membrane 420 may be made of a ceramic material made of raw materials such as alumina (Al ₂ O ₃ ), silicon, and magnesium.

Accordingly, the separation membrane 420 can have excellent abrasion resistance, chemical resistance, and heat resistance as compared with the conventional organic film.

Since the filtration apparatus 400 is filtered using the ceramic separator 420, it is possible to filter substances and microorganisms of a size not filtered by the centrifugal separator 200.

For example, the size of the pores provided in the separation membrane 420 may range from 2 탆 to 10 탆. If the pore size is less than 2 mu m, the permeability of the ballast water may be extremely small. If the pore size is more than 10 mu m, it may be difficult to remove microalgae, protozoa, bacteria, viruses and the like. Rule D-2 of the International Convention on Maritime Ballast Water Management of the International Maritime Organization recommends that the emission limits be within the microbial population with a minimum size of 50 μm or less. Accordingly, in the case of the separation membrane applied to the conventional ballast water treatment plant, the level of the filtrateable pores is limited to the level of 50 μm or less for removing zooplankton and phytoplankton. However, in order to remove microalgae, protozoa, bacteria, viruses and the like present in the equilibrium water, a high specification in the range of 10 탆 or less is required, so that there is a need to strengthen the minimum pore range of the separation membrane. Therefore, the size of the pores of the separation membrane 420 applied to the present invention is preferably in the range of 2 탆 to 10 탆. Accordingly, not only zooplankton and phytoplankton but also microalgae, protozoa, bacteria, viruses and the like can be removed together.

The filtering device 400 according to the present invention may be connected to the rear end of the micro bubble generator 300 through the first pipe 22 so that the ballast water containing micro bubbles may be introduced. The microbubbles flowing into the filtration unit 400 can remove contaminants accumulated on the surface of the separation membrane 420 and disinfect the separation membrane 420 by decomposing bacteria and harmful substances on the surface of the separation membrane 420 can do. As a result, the flux can be operated at a high flow rate of the membrane filtration, so that the effect can be maximized due to the characteristics of the ballast water to be stored and processed in a large amount of ballast water in a short time.

As described above, the filtration apparatus 400 according to the present invention is installed at the rear end of the micro bubble generator 300, so that the effect of the ceramic separator 420 can be maximized by micro bubbles.

The ultraviolet sterilizer 500 has one side connected to the filtration device 400 and the other side connected to the ballast water tank 600 and sterilizing the ballast water flowing into the inside by irradiating ultraviolet rays. Specifically, one side may be connected to the filtering device 400 through the second pipe 23, and may be connected to the ballast water tank 600 through the third pipe 25.

Since the ultraviolet sterilizing apparatus 500 according to the present invention inflow the ballast water that has passed through the centrifugal separator 200 and the microbubble and the filtration apparatus 400, the small particles and most of the marine species are disinfected or removed Can be charged. That is, the contamination level of the equilibrium water by the contamination is low because the uncontaminated material has been removed most (for example, 90% or more) in the previous step, so that the efficiency of irradiation intensity by ultraviolet irradiation can be increased.

Specifically, in the conventional ballast water treatment apparatus, when ultraviolet rays are irradiated to the ballast water which has only filtered large particles of foreign matter, the turbidity in the seawater is high, so that the irradiated ultraviolet rays are blocked or absorbed by various kinds of suspended substances , The permeability thereof was rapidly lowered. As a result, there is a problem that it is difficult to effectively sterilize various malignant microorganisms distributed throughout the seawater.

On the other hand, the ultraviolet sterilizing apparatus 500 according to the present invention irradiates ultraviolet rays to the ballast water in a state where a small size material and microorganisms are disinfected and removed in the previous step, so that the sterilizing effect by ultraviolet rays can be maximized.

As described above, the ship ballast water treatment system 100 according to the present invention can prevent secondary contamination since each device is connected to a pipeline and there is no storage tank at each stage, and a microbubble- and ceramic- 420, the ballast water can be treated in accordance with the ballast water regulations of the International Maritime Organization and stored in the ballast water tank 600 or discharged to the sea area.

An example of the filtration apparatus 400 will be described in detail with reference to Figs. 5 and 6. Fig. However, the filtration apparatus 400 and the separation membrane 420 applied thereto are not limited to the illustrated embodiment, and various modifications can be made as long as the filtration of the equilibrium water is performed by applying the ceramic separator 420 .

Referring to FIG. 5, the separation membrane 420 can filter the ballast water flowing into the filtration apparatus 400 by a cross flow filtration method. Specifically, the separation membrane 420 separates the ballast water flowing into the filtration unit 400 from the permeated water that is filtered through the inside of the separation membrane 420 and the concentrated water containing the contaminants outside the separation membrane 420 The water can be separated and discharged.

More specifically, the ballast water that has passed through the microbubble generator 300 may be introduced into the filtration unit 400 through the first pipe 22. The permeated water, which is a part of the inflowing ballast water, can be permeated into the separation membrane 420 and introduced into the ultraviolet sterilizing apparatus 500 through the second pipe 23. In addition, the concentrated water that has not permeated through the separation membrane 420 in the introduced ballast water can be discharged through the concentrated water pipe 24.

The cross-flow filtration method has an advantage in that the possibility of contamination of the separation membrane 420 is low, the frequency of exchange of the separation membrane 420 is low, and the system can be regenerated by backwashing, compared with the conventional dead end flow filtration system .

6, the separation membrane 420 is provided with a receiving space 422 in which a ballast water is received, and is provided in the form of a disk of a disk, and can be rotatably provided.

Specifically, the filtration apparatus 400 may further include a housing 410, a rotation shaft 430, and a rotation driving member 440.

The housing 410 includes a second pipe 23 connected to the first pipe 22 communicating with the micro bubble generator 300 on the lower side and communicating with the ultraviolet sterilizer 500 on the upper side, 200 may be connected to the concentrated water pipe 24. The separator 420 and the ballast water may be accommodated in the housing 410.

The rotary shaft 430 may be rotatably mounted on the housing 410. Then, the rotation driving member 440 can provide rotational force to the rotating shaft 430. For example, the rotation driving member 440 may be a driving motor connected to the rotation shaft 430 accommodated in the housing 410 to transmit rotational force to the rotation shaft 430. However, the present invention is not limited thereto, and various modifications are possible.

A plurality of the separation membranes 420 may be spaced apart from each other in the longitudinal direction of the rotating shaft 430 and the accommodation space 422 inside the separation membrane 420 may communicate with the second piping 23.

Here, the separation membrane 420 may include a body 421, a center hole 423, and a through channel 424.

As described above, the body 421 may be made of a ceramic material, a receiving space 422 may be formed therein, and the ballast water may be transmitted from the outside to the inside or from inside to outside. On the other hand, the center hole 423 can be formed to pass through the center of the main body 421 so that the rotation shaft 430 is fitted.

The through channel 424 may be formed through the surface of the body 421 facing the center hole 423. [ That is, a plurality of holes may be formed through the side surface of the center hole 423. Here, the rotation shaft 430 may be formed with a hole (not shown) that is fitted in the center hole 423 and communicates with the through-channel 424. The ballast water flowing into the receiving space 422 through the holes and the through channels 424 can be moved to the rotating shaft 430.

In addition, the inside of the rotating shaft 430 can communicate with the second pipe 23. At this time, there is no limitation on the connection method of the rotation shaft 430 and the second pipe 23, and various types are applicable as long as the ballast flowing into the rotation shaft 430 and connected to the upper pipe 23 can be connected to the second pipe 23 . For example, it may be coupled to the upper side of the rotary shaft 430, and the coupling pipe may be connected to the inside of the rotary shaft 430 and the second pipe 23 to be connected. This coupling can be sealed at the top of the housing 410, and the rotation shaft 430 can be rotatably provided.

The operation of the filtration apparatus 400 when the ballast water is stored in the ballast water tank 600 will be described. First, when the ballast water containing the microbubbles flows through the first pipe 22, some ballast water may permeate through the separation membrane 420 and enter the internal space 422 due to the inter-membrane pressure difference.

The inflowing ballast water moves to the center of the main body 421 and moves to the inside of the rotating shaft 430 through the through channel 424 and then moves upward along the rotating shaft 430. Then, the ultraviolet sterilizing device 500 can be moved through the second pipe 23 connected to the rotating shaft 430. On the other hand, the ballast water that has not permeated through the separation membrane 420 in the influent ballast water can be discharged through the concentrated water pipe 24 with concentrated water containing biological species and contaminants of a predetermined size or larger.

On the other hand, the microbubbles can decompose and disinfect the contaminants on the surface of the separation membrane 420 by the self-pressurization phenomenon described above. In addition, the rotation shaft 430 is rotated by the rotation driving member 440, so that the plurality of separation membranes 420 can rotate. The adhesion of contaminants to the surface of the body 421 can be minimized by preventing the contaminants attached to the surface of the body 421 of the separation membrane 420 from being torn or adhered by the rotation of the separation membrane 420 .

As described above, the separation membrane 420 applied to the present invention can prevent the differential pressure of the separation membrane 420 from increasing due to the function of decomposing the microbubbles contained in the ballast water and the function of reducing contaminant accumulation due to the rotation of the separation membrane 420 It is possible to minimize the rise. Accordingly, it is possible to prevent an increase in the driving pressure of the separation membrane 420 and to save energy compared to the separation membrane 420 of a general ceramic material.

According to the present invention, since the accumulation of contaminants on the surface of the separation membrane 420 is prevented, the filtration time of the separation membrane 420 can be maintained for a long time and the flux, which is the membrane filtration flow rate per unit area, have. Accordingly, even though the separation membrane 420 using the cross-flow filtration method is used, a high flux of the level of the Dead End Flow system can be achieved, and thus an excellent effect of processing and storing a large amount of seawater in a short time can be obtained .

Hereinafter, a method for treating ship equip- ment water according to another aspect of the present invention will be described with reference to the embodiments shown in Figs. 1 to 4. Fig. The ship ballast water treatment method described below uses the structure of the ship ballast water treatment system 100 described above, and a detailed description of the same components as those described above will be omitted.

The ship ballast water treatment method according to an embodiment of the present invention may include a storage step and a discharge step.

In the storing step, the ballast water can be stored in the ballast water tank 600. Fig. 1 is a block diagram showing a storing step, and Fig. 2 is a flowchart showing a storing step.

1 and 2, the storing step may include a separating step S120, a micro bubble generating step S130, and a filtering step S140. In addition, it may further include a raw water inflow step (S110) and a ballast water tank storage step (S160), and may further include an ultraviolet sterilization step (S150).

First, raw water such as seawater may be introduced into the centrifuge 200 through the raw water pipe 11 in the raw water inflow step (S110). Such seawater can be provided as ballast water.

In the separation step (S120), the introduced ballast water can be introduced into the centrifugal separator (200) to separate the foreign matter. Specifically, the inflow of the ballast water is separated by centrifugation, so that floating substances and some marine organisms larger than a predetermined size can be discharged through the first discharge portion 31. In addition, the ballast water, which is the raw water having a predetermined size or more and the water from which some marine life has been removed, can be moved to the microbubble generator 300 through the production water pipe 21.

Meanwhile, in the micro bubble generating step S130, microbubbles may be generated in the equilibrium water by introducing the separated water into the micro bubble generator 300 in the separation step S120.

The micro bubble generated in the micro bubble generating step (S130) can decompose bacteria and harmful chemical substances present in the equilibrium water by the self-pressurizing phenomenon. Here, the micro bubble generator 300 may be a turning system that generates a bubble to generate micro bubbles by turning the ballast water. Thus, it is possible to provide an effect of reducing power consumption through independent self-excitation.

In this way, the large particles are separated and removed in the separation step S120, and the ballast water in which the harmful substances are decomposed in the microbubble generation step S130 is discharged through the first pipe 22 together with the microbubbles, 400). ≪ / RTI >

In the filtration step S140, the microbubble-containing ballast water that has passed through the microbubble generation step S130 flows into the filtration device 400 connected to the microbubble generator 300, The ballast water can be filtered by the separation membrane 420 made of a ceramic material.

Since the filtration apparatus 400 is filtered using the ceramic separator 420, it is possible to filter small particles and microorganisms of a size not filtered by the centrifugal separator 200. Specifically, the size of the pores provided in the separation membrane 420 is preferably in the range of 2 탆 to 10 탆.

The separation membrane 420 used in the present invention can remove microalgae, protozoa, bacteria, viruses and the like by using the pores having a size in the range of 2 탆 to 10 탆.

In addition, in the filtration step S140, the micro bubbles flowing into the filtration apparatus 400 may desorb the contaminants accumulated on the surface of the separation membrane 420 and decompose bacteria and harmful substances on the surface of the separation membrane 420 Thereby sterilizing the separation membrane 420. As a result, the flux can be operated at a high flow rate, which is a membrane filtration flow rate, so that an effect of treating a large amount of ballast water in a short time can be obtained.

The rotation of the separation membrane 420 rotatably provided in the filtration step S140 prevents the contaminants adhering to the surface of the body 421 of the separation membrane 420 from being detached or adhered, ) The adhesion of contaminants to the surface can be minimized.

As described above, the filtration apparatus 400 applied to the present invention is a filtration apparatus 400 installed at the downstream end of the micro bubble generator 300 and adapted to apply a rotary cross filtration type separation membrane 420 to the separation membrane 420 of the ceramic material, The filtration effect can be maximized.

In the ultraviolet sterilization step S150, after the filtration step S140, the filtered ballast water is introduced into the ultraviolet sterilizing apparatus 500, and ultraviolet rays are irradiated to sterilize the ballast water.

Specifically, the filtered ballast water in the filtration apparatus 400 may be introduced into the ultraviolet sterilizing apparatus 500 through the second pipe 23. Since the ballast water flowing into the ultraviolet sterilizing apparatus 500 flows through the centrifugal separator 200 and the microbubbles and the filtration apparatus 400, Can be charged. That is, the contamination level of the equilibrium water by the contamination is low because the uncontaminated material has been removed most (for example, 90% or more) in the previous step, so that the efficiency of irradiation intensity by ultraviolet irradiation can be increased.

In step S160 of storing the ballast water in the ballast water tank 600, sterilized ballast water in the ultraviolet sterilization step S150 may be stored in the ballast water tank 600 through the third pipe 25. At this time, the ballast water stored in the ballast water tank 600 may be stored in the ballast water tank 600 in a state that the ballast water is processed to comply with the ship ballast water treatment regulations of the International Maritime Organization.

On the other hand, as in the embodiment shown in Fig. 4, in the discharging step, the ballast water stored through the storing step can be discharged from the ballast water tank 600 to the outside.

Specifically, the discharging step may include an ultraviolet irradiation step and an equilibrium drainage step.

In the ultraviolet ray irradiation step, the ballast water stored in the ballast water tank 600 may be supplied to the ultraviolet sterilizing apparatus 500 through the third pipe 25, and the ballast water may be sterilized by irradiating ultraviolet rays. Since the ballast water stored in the ballast water tank 600 is a high-quality water produced by removing all the suspended substances and small marine life, it is possible to satisfy the ballast water discharge condition of the International Maritime Organization only by disinfection by ultraviolet irradiation.

In the ballast water draining step, the ballast water sterilized by the ultraviolet irradiation step can be discharged to the outside through the second discharge portion 32.

On the other hand, although not shown, the discharging step may further include a step of injecting the filtration apparatus 400 as another embodiment.

The filtration device 400 is charged with the ballast water stored in the ballast water tank 600 into the filtration device 400 and filtering the ballast water by the separation membrane 420 before the ultraviolet ray irradiation step, (500). Accordingly, even when the microorganisms are grown in the ballast water tank 600, they can be filtered by the separation membrane 420 and then disinfected and discharged.

Meanwhile, as in the embodiment shown in FIG. 3, the ship ballast water treatment method according to the present invention may further include a backwashing step.

The backwashing step is a step in which the ballast water stored in the ballast water tank 600 is filtered through the filtration unit 400 when a predetermined time has elapsed since the start of the filtration step S140 or when the pressure difference between the inflow and outflow of the filtration unit 400 reaches a predetermined range The filtration device 400 can be backwashed by supplying the filtrate to the device 400 in reverse.

For example, when the separation membrane 420 made of ceramic material is backwashed with a filtration time of one time per 2 hours on the basis of surface water, or when the differential pressure of the separation membrane 420 reaches a range of 150 to 200 kPa, . However, the conventional conventional backwashing method has a short backwash cycle and thus has a limitation in continuously storing a large amount of ship ballast water.

As described above, according to the present invention, since the accumulation of contaminants on the surface of the separation membrane 420 is remarkably reduced by the decomposition of the micro bubbles and the rotation of the separation membrane 420, the backwash cycle during the filtration time is extended can do.

Specifically, the backwashing step may include an ultraviolet sterilization step, a first cleaning step, and a concentrated water drainage step.

The ultraviolet disinfecting step may be performed by introducing the ballast water into the ultraviolet sterilizing apparatus 500 from the ballast water tank 600 and disinfecting it by irradiating ultraviolet rays.

The ballast water sterilized in the ultraviolet disinfecting step may be introduced into the filtration unit 400 through the second pipe 23. That is, the treatment system 100 according to the present invention can perform a backwash process using the ballast water stored in the ballast water tank 600 as a reverse water wash.

In the first cleaning step, after the ultraviolet disinfection step, the ballast water is introduced into the filtration unit 400 and the ballast water is permeated to the outside from inside the separation membrane 420 to remove contaminants from the surface of the separation membrane 420 .

5 and 6, the ballast water flowing into the filtration apparatus 400 flows through the second pipe 23 and flows into the separation pipe 420, which is in communication with the second pipe 23, As shown in FIG. The ballast water flowing into the accommodation space 422 is transmitted from the inside to the outside of the separation membrane 420 and contaminants formed on the outer surface of the separation membrane 420 can be desorbed at a high flow rate.

In the concentrated water drain step, concentrated water, which is a ballast water containing contaminants, generated in the filtration unit 400 through the first washing step is supplied to the centrifugal separator 200 and is discharged to the outside by centrifugal separation .

Further, the backwashing step may further include a second cleaning step.

The second backwashing step is a step of returning the ballast water supplied from the centrifugal separator 200 to the filtration device (not shown) via the microbubble generator 300, together with the first cleaning step, after a predetermined time has elapsed after the start of the first cleaning step 400, the contaminants on the surface of the separation membrane 420 can be desorbed by microbubbles contained in the ballast water.

For example, when the backwashing time is 2 minutes to 4 minutes, the centrifugal separator 200 can discharge all the equilibrium water, which is the incoming reverse water, for 1 minute to 2 minutes in the early half. The centrifugal separator 200 opens the product water pipe 21 to circulate the ballast water of the centrifugal separator 200 through the microbubble generator 300 and the filtration device 400, As shown in FIG.

Accordingly, in the second cleaning step, the ballast water introduced from the centrifugal separator 200 and the microbubble generator 300 can circulate to the outer surface of the separation membrane 420. Accordingly, the microbubbles can be removed while flushing contaminants that have not yet desorbed from the outer surface of the separation membrane 420.

This second cleaning step is performed together with the first cleaning step, thereby maximizing the backwash effect of the separation membrane 420. In addition, in the second cleaning step, the ballast water discharged into the centrifugal separator 200 flows into the filtration unit 400 again to circulate the outer surface of the separation membrane 420, so that the ballast water stored in the ballast water tank 600 There is an advantage to be consumed. Therefore, the total amount discharged through the first discharge portion 31 is the same, but the amount of the ballast water used in the backwashing step is decreased, so that the recovery rate of the separation membrane 420 is increased.

The backwashing step according to the present invention does not require the addition of a disinfectant such as sodium hypochlorite for disinfection, and there is no need to inject additional air at the time of backwashing. In addition, the ballast water stored in the ballast water tank 600 can be disinfected and reused as backwash water, thereby improving the recovery rate of the separation membrane 420.

As described above, the ballast water treatment method according to the present invention can drive the ballast water storing step, the backwashing step, and the discharging step all through one processing system 100. Therefore, the required site for the ballast water treatment is reduced and the processing cost is reduced.

Hereinafter, effects of the ship ballast water treatment system and the treatment method according to the present invention will be described with reference to the graphs shown in Figs. 7 to 13. Fig. The graphs shown in FIGS. 7 to 13 show experimental examples using the ship ballast water treatment system and method according to the present invention. However, the practice of the present invention is not limited to these specific examples.

7 is a graph showing the turbidity and turbidity removal rates in the experimental examples using the centrifugal separator 200 and the filtration apparatus 400 according to the present invention. The experimental example shown in FIG. 7 is for raw water in the west coast, and the turbidity and the removal rate in the centrifugal separator 200 and the filtration apparatus 400 are measured. Here, NTU (Nephelo-metric Turbidity Unit) is used as a unit representing the degree of turbidity.

Referring to FIG. 7, it can be seen that the turbidity of the raw water is 46.4 NTU, the turbidity in the centrifuge 200 is 18.7 NTU, and the turbidity in the filtration apparatus 400 is 1.47 NTU. It can be seen that the turbidity removal rate is 60% in the centrifuge 200 and 92% in the filtration apparatus 400.

Therefore, it can be seen that the use of the present invention partially secures the removal of the contaminants due to the difference in specific gravity due to the fast flow rate in the centrifugal separator 200, and the fine suspended substances and marine organisms It can be seen that most of it is removed through the ceramic separator. Thus, as described above, the sterilization efficiency by ultraviolet irradiation in the ultraviolet sterilizing apparatus 500 can be increased.

FIG. 8 is a graph showing filtration performance depending on the type of separator applied to the filtration apparatus 400. FIG. A is an experimental example of a rotating type cross flow filtration type membrane according to the present invention, B is a comparative example of a general cross flow filtration type not rotating type, C is a total filtration type End Flow Filtration) method.

Referring to FIG. 8, it can be seen that the filtration performance of the separation membrane using the cross-flow filtration system is superior to the filtration performance of the separation membrane using the full-volume filtration system. Further, it can be seen that the filtration performance of the rotary cross-flow filtration system according to the present invention is better than that of the conventional cross-flow filtration system. This is because the accumulation of contaminants on the surface of the separation membrane is prevented by the rotation of the separation membrane as described above.

9 is a graph showing a cost reduction according to the type of separation membrane applied to the filtration apparatus 400. FIG. A is an experimental example of a rotating type cross-flow filtration (cross-filtration) type separator according to the present invention, and B is a comparative example of a general cross-flow filtration type.

Referring to Fig. 9, the rotatable separator (A) shows an energy saving effect that the power ratio is reduced by 80% as compared with the conventional separator (B). As a result, it can be seen that the rotational separation membrane (A) is reduced in operating cost as compared with the conventional separation membrane (B).

10 is a graph comparing the filtration speed and the intermuscular correction pressure difference according to the type of the filtration apparatus 400. As shown in FIG. D is a comparative example of a ceramic material separator in which microbubbles are not applied, and E is an example of a ceramic material separator in which microbubbles are applied.

Referring to FIG. 10, in the separation membrane D to which the conventional micro bubble is not applied, the corrected differential pressure increases with the lapse of time, whereas the separation membrane E of the ceramic material to which micro bubbles are applied, It can be seen that the inter-film compensating differential pressure is kept constant. That is, in the graph of the corrected differential pressure over time, the slope represents the rate of increase of the corrected differential pressure for a certain time, and since the slope of E is smaller than D, the corrected differential pressure of E is maintained more constant than D have. Therefore, it can be seen from the results of FIG. 10 that the correction pressure difference is maintained constant in the case of the separation membrane E to which micro bubbles are applied, and thus the rise of the driving pressure can be controlled.

Referring to FIG. 10, it can be seen that the membrane (E) of a ceramic material to which microbubbles are applied according to the present invention has a flux (LMH) of 100 LMH or more, which is a membrane filtration flow rate per unit area. This is a high filtration flow rate considering that the maximum flux is about 80 LMH in the case of a membrane of a typical organic membrane. That is, since the separation membrane according to the present invention uses a rotary type separation membrane to which micro bubbles are applied, it is possible to realize a high flux of the conventional total filtration level despite the cross flow filtration system. Therefore, by using the present invention, a large amount of seawater can be treated in a short time.

On the other hand, Fig. 11 is a graph showing a change in the inter-film correction pressure difference and a correction differential pressure in the future depending on the type of the filtration device 400. Fig. D is a comparative example of a ceramic material separator in which microbubbles are not applied, and E is an example of a ceramic material separator in which microbubbles are applied. In addition, the time between the initial pressure difference and the pressure difference after operation in the illustrated comparative example and the experimental example is the same condition.

Referring to FIG. 11, it can be seen that in the case of D, the differential pressure after operation is increased by 5.2 bar compared with the initial differential pressure, whereas the differential pressure increase rate by E is 0.2 bar. Accordingly, in case of D, the differential pressure required for filtration of the separator is 160 days to reach the differential pressure of 200 kPa, while in case of E, the differential pressure at the point of 160 days is expected to be 84.6 kPa.

According to the experimental results shown in FIG. 11, in the case of the ceramic material separation membrane to which the microbubbles applied in the present invention are applied, the accumulation of contaminants on the separation membrane surface due to the application of microbubbles is prevented, Can be confirmed. Therefore, according to the present invention, since the differential pressure increase rate of the separation membrane is low, the backwash cycle of the separation membrane is extended, so that the filtration time can be further extended.

12 is a graph showing the relationship between the amount of the concentrated water discharged from the filtration apparatus 400 and the amount of the concentrated water discharged from the filtration apparatus 400 in the case where the microbubbles are not applied to the filtration apparatus 400, And the turbidity of the waste water.

Referring to FIG. 12, it can be seen that the initial turbidity of the concentrated water (D) when the microbubbles are not applied in the backwashing step is 12.5 NTU, whereas the initial turbidity of the microbubbles (E) is 46.4 NTU . Accordingly, when the microbubbles are applied together, the contaminants on the surface of the separation membrane are more easily removed in the backwashing step, so that the initial removal of the contaminants is smoother. Therefore, it can be confirmed that the use of the present invention has a superior backwash effect by removing contaminants that have not yet been desorbed due to application of microbubbles.

13 is a graph showing the recovery rate depending on the type of the filtration apparatus 400. Fig. F is an experimental example of a cross-flow filtration type separation membrane using the backwashing step according to the present invention. G and H are comparative examples of membrane by total volume filtration method for existing surface water.

In the case of the recovery rate of a conventional separation membrane, the recovery rate of the separation membrane of the full-volume filtration system is 94% or more, while the recovery rate of the separation membrane of the conventional cross-flow filtration system is about 92%. However, referring to FIG. 13, it can be seen that the recovery rate of the separation membrane applied to the present invention maintains a high recovery rate of 94.6% despite the cross-flow filtration system. It can be seen that the recovery rate is similar to that of G and H, which is a comparative example according to the entire filtration system.

As described above, in the second cleaning step in the backwashing step, the ballast water discharged into the centrifugal separator 200 flows into the filtration unit 400 again to circulate the outer surface of the separation membrane, 600 is less consumed. Therefore, the total amount discharged through the first discharge portion is the same, but since the use of the ballast water in the backwashing stage is low, the recovery rate of the separation membrane can be increased.

The ship ballast water treatment system and method according to the present invention can prevent secondary contamination because each device is connected to a pipeline and there is no reservoir at each stage. In addition, since the microbubble and ceramic material separation membrane can increase the disinfection and filtration efficiency of the ballast water, the ballast water can be stored in the ballast water tank or discharged into the ballast water tank in accordance with the ballast water treatment regulations of the International Maritime Organization can do.

According to the present invention, since the accumulation of contaminants on the surface of the separation membrane is prevented, the differential pressure of the separation membrane can be prevented from rising and the filtration time of the separation membrane can be maintained for a long time and the flux as the membrane filtration flow rate per unit area can be increased . Accordingly, despite the separation membrane using the cross-flow filtration method, high flux can be realized similar to the full-volume filtration method, so that the effect of the ballast water to be stored and stored in a large amount of ballast water in a short time can be maximized have.

In addition, according to the present invention, there is no need to add disinfectant in the backwashing step, and there is no need to inject air separately at the time of backwashing. In addition, the ballast water stored in the ballast water tank can be disinfected and reused as backwash water, thereby improving the recovery rate of the separation membrane. By removing the contaminants which can not be removed only by reverse osmosis by using micro bubbles, the removal efficiency of the contaminants in the separation membrane can be increased.

While the invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, And various modifications and changes may be made without departing from the scope of the present invention.

100: Ship ballast water treatment system 200: Centrifuge
300: Micro bubble generator 400: Filtration device
410: Housing 420: Membrane
421: main body 422: accommodation space
423: center hole 424: through channel
430: rotating shaft 440: rotating driving member
500: ultraviolet sterilization apparatus 600: ballast water tank
21: Production water piping 22: First piping
23: second piping 24: concentrated water piping
25: third piping 31: first discharge section
32:

Claims (15)

A ship ballast water treatment system for treating ballast water flowing into a ballast water tank of a ship,
A centrifugal separator for separating foreign matter from the ballast water using a specific gravity difference;
A micro bubble generator connected to a rear end of the centrifugal separator and generating micro bubbles in the ballast water introduced from the centrifugal separator;
A filtration device which includes a ceramic separator inside and which is connected to a rear end of the micro bubble generator and filters the ballast water containing the micro bubble introduced into the inside thereof; And
And an ultraviolet sterilizer for sterilizing the ballast water flowing into the ballast water tank, the other side of which is connected to the filtration device,
Wherein the separation membrane is provided with a receiving space in which the ballast water is received, is provided in the form of a disk of a disk, is rotatably provided,
And the size of the gap provided in the separation membrane is in the range of 2 탆 to 10 탆. The method according to claim 1,
The separation membrane separates the ballast water flowing into the filtration device into permeated water that is filtered through the inside of the separation membrane and concentrated water that is a ballast water containing pollutants outside the separation membrane and is discharged through a crossflow filtration The system of claim 1, delete The method according to claim 1,
The filtration device comprises:
And a second pipe connected to the microbubble generator at a lower side and connected to the ultraviolet sterilizing device at an upper side and a second pipe connected to the microbubble generator at an upper side and a concentrated water pipe for discharging concentrated water, A housing;
A rotating shaft rotatably installed in the housing; And
And a rotation driving member for providing a rotational force to the rotation shaft,
Wherein the separation membrane is disposed so that a plurality of the separation membranes are spaced apart in the longitudinal direction of the rotary shaft, and the accommodation space communicates with the second pipe. 5. The method of claim 4,
The separation membrane includes:
Wherein the accommodating space is formed in the body and the ballast water is permeated therethrough;
A center hole penetrating the center of the main body so as to fit the rotation shaft; And
Further comprising a through channel formed in the main body so as to pass through the surface facing the center hole so that the ballast water accommodated in the accommodating space moves upward along the rotation axis, Water treatment system. delete The method according to claim 1,
Wherein the micro bubble generator generates the micro bubble by pivoting the ballast water. The method according to claim 1,
A production water pipe connecting the centrifugal separator and the micro bubble generator; And
An ultraviolet sterilizing device, and a third pipe connecting the ballast water tank. A ship ballast water treatment method for treating ballast water flowing into a ballast water tank of a ship,
A storing step of storing the ballast water in the ballast water tank; And
And a discharging step of discharging the ballast water stored through the storing step to the outside from the ballast water tank,
Wherein,
A separating step of separating foreign matter by introducing the introduced ballast water into a centrifugal separator;
A micro bubble generating step of introducing the ballast in which the foreign substance is separated in the separation step into the micro bubble generator to generate micro bubbles in the ballast water; And
The ballast including the micro bubbles which has passed through the micro bubble generating step is introduced into the filtration apparatus connected to the micro bubble generator and the ballast water is filtered by the ceramic material separation membrane provided in the filtration apparatus Comprising a filtration step,
Wherein when the predetermined time elapses after the filtration step is started or when the differential pressure between the inside and the outside of the separation membrane reaches a predetermined range, the ballast water stored in the ballast water tank is supplied to the filtration apparatus, Further comprising:
Wherein the backwashing step includes a first cleaning step of permeating the ballast water supplied from the ballast water tank from the inside to the outside of the separation membrane to remove contaminants on the surface of the separation membrane,
Wherein the backwashing step includes, when a predetermined time elapses after the start of the first cleaning step, the balloon supplied from the centrifugal separator, together with the first cleaning step, is introduced into the filtration device through the microbubble generator Further comprising a second cleaning step of removing contaminants on the surface of the separation membrane by the microbubbles included in the ballast water. The method of claim 9, wherein
Wherein,
Further comprising an ultraviolet sterilizing step of infusing the filtered ballast water into the ultraviolet sterilizer after the filtering step and irradiating ultraviolet rays to sterilize the ballast water. delete 10. The method of claim 9,
The back-
An ultraviolet disinfecting step of infusing the ballast water into the ultraviolet sterilizing apparatus in the ballast water tank and irradiating ultraviolet rays to disinfect the ballast water before the first washing step; And
And a concentrated water drainage step of supplying concentrated water, which is a ballast water containing contaminants, generated in the filtration apparatus through the first cleaning step to the centrifugal separator and discharging the concentrate water to the outside by centrifugal separation, Water treatment method. delete 11. The method of claim 10,
Wherein the discharging step comprises:
An ultraviolet light irradiation step of supplying the ballast water stored in the ballast water tank to the ultraviolet sterilizing apparatus and disinfecting the ballast water by irradiating ultraviolet rays; And
And a ballast water draining step of draining the ballast water sterilized by the ultraviolet irradiation step to the outside. 15. The method of claim 14,
Wherein the discharging step comprises:
Further comprising the step of injecting the ballast water stored in the ballast water tank into the filtration apparatus, filtering the ballast water by the separation membrane, and then introducing the ballast water into the ultraviolet sterilization apparatus before the ultraviolet ray irradiation step The method of treating ballast water of ship.

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