MX2013008646A - Flocculation magnetic separation device. - Google Patents

Abstract

Provided is a flocculation magnetic separation device that is able to reduce recovered floc and reduce the amount of used magnetic powder without using a chemical such as hydrochloric acid. The flocculation magnetic separation device has a return addition device (18) that returns recovered floc discharged from a magnetic separation device (16) to a raw water supply tube (12) at a position upstream of a rapid agitation tank (26) before the addition of a flocculant. By means of returning recovered floc to the raw water supply tube (12), it is possible to reuse recovered floc without using a chemical such as hydrochloric acid. Also, as it is possible to reuse magnetic powder contained in the recovered floc, it is possible to reduce the amount of new magnetic powder used.

Description

MAGNETIC SEPARATION DEVICE FOR FLOCCULATION FIELD OF THE INVENTION The present invention is concerned with a magnetic flocculation separation device for the flocculation of plankton and bacteria contained in ballast water and the separation of the flocs thus collected by magnetic force.

BACKGROUND OF THE INVENTION In accordance with the International Convention for the Control and Management of Water Ballast Water adapted by the International Maritime Organization (IMO) in 2004, it is demanded that the ships are equipped with a system to remove or sterilize plankton and bacteria contained in ballast water. This convention was adopted with the objective of preventing microorganisms from moving through ballast water (or seawater), the ecosystem being destroyed via the spread of microorganisms and a health hazard of being caused by microorganisms.

At present, technologies for treating ballast water are actively developed by combining a variety of water treatment technologies, including chemical treatment using sodium hypochlorite or the like, ozonation, ultraviolet irradiation, heat treatment and magnetic separation or the like.

Herein, a magnetic flocculation separation device disclosed in the patent document 1 is put into operation by the steps of: adding magnetic powder and a flocculant to ballast water (or raw water); stirring the resulting mixture to form magnetic flocs containing microorganisms and bacteria mixed in the ballast water; separating the magnetic flocs from the ballast water by means of a magnetic separation device and collecting relatively large solid materials unfit to be flocculated by themselves (eg, small fish each with a size of several millimeters and marine weeds) by means of a filter type dam.

When the magnetic flocculation separation device is put into operation, the flocculant used is a highly safe agent that is also used for the water treatment of the faucet. In addition, such water treatment using a flocculant is less risky than a treatment using chemicals such as chlorine. In other words, treatment by flocculation has less responsibility for secondarily contaminating the environment by the chemical compounds that remain in the ballast water at discharge time and related byproducts.; In addition, the magnetic flocculation separation device flocculates not only microorganisms and bacteria but also sand and mud included in the ballast water, to separate simultaneously and remove all materials by this. This allows the magnetic flocculation separation device to have a side effect of preventing sand and mud from accumulating at the bottom of a ballast tank.

However, there are the following issues that arise in the magnetic flocculation separation device disclosed in the patent document 1. One issue is that the quantities used of the expensive magnetic powder must be reduced, while the water cleaning performance is maintained. of ballast The other issue is that the total quantities of the flocs collected should be reduced.

That is, with respect to a magnetic flocculation separation device, the magnetic powder thus added must be contained uniformly in all the flocs as much as possible, when the magnetic flocs are formed. By this, if the magnetic powder composed of the particles each having an extremely small particle size of several microns is used as well as an equal particle size.

However, it should be noted that such magnetic powder is very expensive, resulting in increased operating costs of a magnetic flocculation separation device. Therefore, it is required to reduce the used quantities of magnetic powder as much as possible. In addition, assuming that a magnetic flocculation separation device is installed on a ship, the reduced amounts of the magnetic powder allow the storage tank of the magnetic powder to be reduced in size.

This advantage provides a great merit with the installation of the magnetic flocculation separation device inside the ship that has limited space to dispose several devices. Simultaneously, this advantage allows the frequency of operations to supply the magnetic powder to the interior of the ship to be reduced, resulting in a reduction in the load of the sailors.

Meanwhile, collected flocs discharged from the magnetic separation device have to be stored in a tank and treated as an industrial waste. Thus, it is strongly demanded that the collected flocs should be recycled as much as possible to reduce the total amount thereof, to reduce by this size the storage tank thereof, obtain space savings and reduce the costs of waste treatment industrial From the points of view as mentioned above, it will be noted that the patent document 2 discloses a magnetic separation cleaner having the following appearance. That is, the magnetic separation cleaner it is put into operation in the stages of: adding hydrochloric acid to the flocs collected with agitation of the mixture; decomposition of a polymeric flocculant to be separated by this to a decomposed flocculant containing an oil and treated water and a magnetic powder component and returning the decomposed flocculant and magnetic powder to the raw water to recycle those materials.

PRIOR ART DOCUMENTS PATENT DOCUMENTS Patent Document 1: JP H09-117618 Patent Document 2: JP 2006-718 DISCLOSURE OF THE INVENTION PROBLEMS TO BE RESOLVED BY THE INVENTION In the patent document 2, hydrochloric acid is used to recycle the magnetic powder. In it, it should be noted that the use of hydrochloric acid on a ship needs to present proof documents with the IMO; documents that demonstrate the safety of installing a treatment system that uses hydrochloric acid, that is, a strong acid. In addition, additional proof documents are required to be presented with the IMO; the documents that demonstrate the trustworthiness in the process of neutralizing the treated materials.

Thus, such extremely complicated procedures are required to use such a treatment system in which hydrochloric acid is used.

From the circumstances as described hereinabove, it has been demanded to develop a magnetic flocculation separation device which is able to reduce the quantities of the flocs collected also as the quantities used of the magnetic powder; the magnetic flocculation separation device is capable of physically separating microorganisms and microorganisms included in the ballast water as described in patent document 1.

Here, a problem caused by a process of reducing the amounts used of the magnetic powder and the amounts of the collected flocs without using a chemical compound such as hydrochloric acid to treat raw water, is not limited only to the case of ballast water treatment. The same problem arises in the case of raw water :: which is treated on the coast.

The present invention has been developed in light of the problems as described above. Accordingly, it is an object of the present invention to provide a magnetic flocculation separation device capable of reducing the amounts of magnetic powder used without using a chemical compound such as hydrochloric acid, as well as the amounts of the flocs collected, to treat water raw MEANS TO RESOLVE THE PROBLEMS Thus, the present invention has been made in order to obtain the object mentioned above. That is, a magnetic flocculation separation device is provided which includes: a first agitation tank to form magnetic microflocks containing magnetic powder and a second agitation tank to expand the magnetic microflocks via agitation of the raw water to which a polymeric flocculant has been added In the present, the first stirring tank is connected to a raw water supply pipe to supply raw water and the magnetic microflocks are formed by rapidly stirring the raw water to which the magnetic powder and a flocculant have been added. Such magnetic powder is supplied from a magnetic powder supply device. In addition, the raw water to be treated in the second agitation tank contains the magnetic microflocks discharged from the first agitation tank. The second tank is agitated at a rotational speed lower than the rotational speed of the first tank.

In addition, the magnetic flocculation separation device includes: a magnetic separation device to collect the expanded flocs by force magnetic and a return and addition device for returning the flocs thus collected by the magnetic separation device to the raw water supply tube located in a position upstream of the first agitation tank and in an upstream position where the flocculant is added to raw water. Then, the return and addition device adds the collected flocs to the raw water.

Herein, the magnetic flocculation separation device of the present invention includes the return and addition device for returning flocs discharged from the magnetic separation device to the raw water supply tube in the upstream position of the first stirring tank and in the upstream position where the flocculant is added. The collected flocs discharged from the magnetic separation device are once stored in a receiver tank of collected flocs. Then, the collected flocs are returned to the raw water supply tube by the return and addition device.

Thus, the magnetic powder contained in the collected flocs is recycled in the present invention. This recycling process allows the used quantities of the magnetic powder to be reduced without using a chemical compound such as hydrochloric acid or the like and in addition quantities of the flocs collected are reduced. In addition, this recycling process allows a complicated separation and extraction treatment of the magnetic powder to be unnecessary. Note that collected flocs that are not returned are allowed to overflow from the collected floccuit receiving tank as excess of the collected flocs, thereby being stored separately in a storage tank of collected flocs.

The magnetic flocculation separation device of the present invention preferably includes a concentration detection device for detecting the concentration of the suspended solids in the raw water in the upstream position where the magnetic powder, the flocculant and the flocs collected are aggregates In addition, the magnetic flocculation separation device preferably includes a control device for controlling the return quantities of collected flocs driven by the return and addition device together with the addition amounts of the magnetic powder driven by the powder supply device. magnetic.

In the present, the control device performs the operation described above based on both the concentration of the suspended solids detected by the concentration detection device as in the maximum concentration of suspended solids in the raw water established in advance.

The control device of the present invention controls the return amounts of the collected flocs carried out by the return and addition device and the addition amounts of the magnetic powder conducted by the magnetic supply device.

Here, the control device performs the operation based on both the concentration of the suspended solids detected by the concentration detection device and the maximum concentration of suspended solids in the pre-established raw water (or designated value of the device). of magnetic separation of flocculation).

According to the present invention, the concentration of the suspended solids in the raw water is detected and subsequently it is confirmed that the concentration detected is lower than the maximum concentration of the suspended solids in the raw water. This procedure allows a complicated separation and extraction treatment to be unnecessary and consequently that the collected flocs be recycled through a simple and low cost system structure. In addition, the process of recycling the magnetic powder contained in the collected flocs allows the quantities used of the new magnetic powder are reduced. By this, the quantities generated from the collected flocs derived from the newly added magnetic powder are also allowed to be further reduced.

Further, in accordance with the present invention, if it is determined that the concentration of the suspended solids detected by the concentration detection device is equal to the maximum concentration of suspended solids in the raw water, preferably the control device stops the process return of collected flocs carried out by the return and addition device. Simultaneously, preferably the control device controls the addition amounts of the magnetic powder driven by the magnetic powder supply device, thereby increasing the return quantities of the collected flocs conducted by the return and addition device, as the concentration of the suspended solids becomes lower than the maximum concentration of the suspended solids in the raw water. Furthermore, preferably, the control device controls the addition amounts of the magnetic powder driven by the magnetic powder supply device, such that the addition amounts thereof will be decreased.

Thus, the aforementioned process of the present invention allows the treatment performance of the magnetic flocculation separation device to be more stabilized, regardless of the concentration of suspended solids in the raw water.

Meanwhile, according to the present invention, if the concentration of the suspended solids in the raw water becomes higher than the maximum concentration of the suspended solids in the raw water, the collected flocs can not be returned to the supply tube of the raw water. raw water. However, in order to return the flocs collected to recycle the magnetic powder included in the flocs collected even in the case mentioned above, the return process needs to extract only the magnetic powder component from the collected flocs and remove other suspended solid components. .

From the points of view as described hereinabove, in the present invention, a magnetic dust extraction device is provided with a return pipe located between the return and addition device and the raw water supply pipe. The magnetic dust extraction device includes: a compression device for compressing the collected flocs by shear force; an extraction device to selectively remove only the powder magnetic from the flocs collected thus compressed by the magnetic force and a return device to return the extracted magnetic powder to the raw water supply tube.

The magnetic powder extraction device of the present invention performs the steps of: extracting the magnetic powder component from the collected flocs and removing other suspended solid components by means of the two-step steps as mentioned hereinabove.

In the stages of the first step, the collected flocs are compressed by applying physical force to them. Note that the collected flocs are formed by strong flocculation of the magnetic powder and other solid components suspended via the aid of an inorganic flocculant and a polymeric flocculant. Accordingly, the compression stage of the strong flocculation is carried out by means of a supersonic wave compression device, an inline mill or a ball mill in order to compress the strong flocculation.

That is, the collected flocs are compressed only by physical force without using any chemical compound such as hydrochloric acid. This allows the risk in the stage caused by leaks of a chemical compound to be lower, providing a high safety element with the stage. As a result, when the extraction unit of the Magnetic dust is installed on a ship, this security element facilitates the procedures of approval of the installation by the IMO are carried out more simply.

Then, in the stages of the second step, the compressed flocs consisting of magnetic powder are extracted from the original collected flocs by means of an extraction device that uses magnetic force. Other suspended solid components are thus separated from the extracted flocs. Then, the extracted collected flocs are returned to the raw water supply tube by a return device.

Note that suspended solid components other than the magnetic powder have been separated from the collected flocs to be returned. By this, the collected flocs consisting of magnetic powder to be returned are highly pure. Thus, the collected flocs can be returned to the raw water supply pipe, although the concentration of suspended solids in the raw water is high.

In the present invention, it is preferable to provide a sterilization device for sterilizing plankton and bacteria contained in the collected flocs, in a return passage of the collected flocs. In the present, the return process is carried out by the return and addition device.

When the magnetic flocculation separation device of the present invention is applied to a ballast water treatment system installed on a ship, the plankton and bacteria contained in the collected flocs are sterilized by a sterilization device. Then, the collected flocs thus sterilized are returned to the raw water supply tube. This procedure can suppress another load, in the raw water by the collected flocs.

EFFECT OF THE INVENTION The magnetic flocculation separation device of the present invention allows the used amounts of magnetic powder to be reduced without using a chemical compound such as hydrochloric acid and also that the quantities used of the collected flocs be reduced.

BRIEF DESCRIPTION OF THE FIGURES Figure 1 is a diagram showing the entire construction of a magnetic flocculation separation device in one embodiment.

Figure 2 is a schematic block diagram showing a base body of the magnetic flocculation separation device that does not include any magnetic dust extraction device. Note that Figure 1 shows the separator equipped with the magnetic dust extraction device.

Figure 3 is a schematic block diagram of the magnetic flocculation separation device of Figure 1.

Figure 4 is a graphical diagram showing the return velocities of the flocs collected in the magnetic flocculation separation device of Figure 2.

Figure 5 is a graphical diagram showing the return velocities of the flocs collected in the magnetic flocculation separation device of Figure 3.

Figure 6 is a graphical diagram showing the relationship between the concentration of the magnetic powder added and the rate of removal of flocs.

Figure 7 is a graphic diagram showing the relationship between the concentration of SS (suspended solids) in raw water and the return velocity of the flocs.

MODALITIES FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of the magnetic flocculation separation device of the present invention will be explained in detail with reference to the appended figures.

Figure 1 is a diagram showing the entire construction of the flocculation magnetic separation device 10 in one embodiment. The flocculation magnetic separation device 10 includes: a raw water supply tube 12; a flocculation unit 14; a magnetic separation unit (or magnetic separation device) 16; a return and addition unit (or return and addition device) 18; a magnetic powder extraction unit (or magnetic powder extraction device) 20; a heat sterilization unit (or sterilization device) 22 and a control unit (or control device) 24.

Note that the magnetic flocculation separation device 10 in the present embodiment is applied to a ballast water treatment system installed on a ship. By this, the separator 10 is equipped with a heat sterilization unit 22. However, as such a flocculation magnetic separator is disposed on the coast, the heat sterilization unit 22 is not an essential component of the separator 10.

Further, if the flocs collected by the magnetic separation unit 16 are returned directly to the raw water supply pipe 12 by means of the return-addition unit 18, the magnetic dust extraction device 20 is also not an essential component of the separator 10. ' The flocculation unit 14 includes a high-speed agitation tank (or first agitation tank) 26 and a low-speed agitation tank (or second agitation tank) 28. The flocculation unit 14 produces magnetic microflocks of the water to be treated (or seawater) that has been supplied through the raw water supply pipe 12. For this operation, the raw water supply pipe 12 is equipped with a magnetic powder supply unit (or magnetic powder supplier). 30 and a flocculant addition unit 32. In addition, a polymeric flocculant addition unit 36 is disposed in a pipe 34 through which the water to be treated is supplied from the high-speed agitation tank 26 to the tank. low speed agitation 28.

The magnetic powder supply unit 30 has a magnetic powder injection pump 38. The rotational speed of the magnetic powder injection pump 38 is controlled by the control unit 24. This mechanism controls the addition amounts of the fresh magnetic powder. added to the raw water supply pipe 12.

In addition, a concentration meter of SS (suspended solids: hereafter referred to as SS) 40 (or turbidimeter) which detects the concentration of suspended solids is attached to a position1 upstream of the raw water supply pipe 12. The data of concentration of SS detected by the SS 40 concentration meter are emitted to the control unit 24. Then, based on the SS concentration data, the control unit 24 controls the rotational speed of the magnetic powder injection pump 38 also as the rotational speed of a collected flock return pump 42 which is a component of the return and addition unit 18.

Based on the mechanism mentioned above, the newly added magnetic powder and the collected flocs are added to the raw water flowing through the raw water supply pipe 12. In the present, note that the position of annexing the SS concentration meter 40 is not limited to the raw water supply tube 12. In this regard, any position of annexation may be preferable insofar as the annexation position is located in the upstream region at which the magnetic powder, the flocculant and the flocs collected are added. For example, the SS 40 concentration meter can be attached to a tank to temporarily store the raw water.

Here, as a magnetic powder, the triionic tetraoxide powder can be preferably used. As a flocculant, a water-soluble inorganic flocculant such as polyaluminium chloride, iron (III) chloride and iron (III) sulfate can preferably be used. Also, as polymeric flocculant, an anionic flocculant and a non-ionic flocculant may preferably be used.

The high-speed agitation tank 26 has a stirring blade (not shown in FIG. 1) that rotates rapidly to stir the mixture of raw water, magnetic powder, a flocculant and the collected flocs that have been added to the raw water. The raw water to which the magnetic powder, a flocculant and the collected flocs have been added is quickly stirred by the stirring blade. This operation allows extremely small magnetic microfloccles each having several tens of microns in size to be formed in the high-speed stirring tank 26. When the magnetic microflocks are formed, the microorganisms and bacteria in the raw water are adsorbed onto the powder magnetic that functions as an adsorption nucleus since the microorganisms and bacteria are electrically charged, to be taken by this in the magnetic microfloc.

The low speed agitation tank 28 is constructed as a multistage agitation tank consisting of a series of multiple tanks. A stirring tank in each stage is equipped with a stirring blade (not shown in Figure 1). As for the agitation tank 28 constructed multistage, the speed of agitation in each tank is adjusted in such a way that the agitation rate is gradually decreased from an upstream agitation tank to a downstream agitation tank. By this, the water to be treated containing the magnetic microflocks and the polymeric flocculant that has been added to the water to be treated are supplied to the low speed agitation tank 28 from the high speed agitation tank 26. As a result, the Agitation rate is gradually decreased along with the agitation tank upstream to the downstream tank.

This mechanism facilitates that the magnetic microfloccles are cultivated, to become by this in enlarged flocs. In addition, since the agitation speed in each tank is gradually decreased, there is little likelihood that the enlarged flocs are broken by the respective agitation blades.

The magnetic separation unit 16 collects the enlarged flocs of the water to be treated, which comprises: a magnetic separation tank 44, a magnetic filter 46, a scraper (not shown in Figure 1) and a conveyor system 48. The water to be treated containing expanded flocs is supplied from the low speed agitation tank 28 to the magnetic separation tank 44. The magnetic filter 46 has for example the shape of a drum rotational and at least part of the filter 46 is immersed in the water to be treated in the magnetic separation tank 44. By this, the magnetic separation filter 46 collects the expanded flocs that are transported in the magnetic separation tank 44 filled with the water to be treated.

Then, the enlarged flocs thus collected (or collected flocs) are raised to the magnetic separation tank 44 associated with the rotational movement of the magnetic filter 46. The raised, enlarged flocs are scraped from the magnetic filter 46 by the scraper. After this, the collected flocs to be scraped are transported to a recipient tank of flocs collected 50 by the conveyor system 48 such as a screw conveyor. The flocs collected thus transported are temporarily stored in tank 50.

The collected flocs stored in the collected flock receiving tank 50 are sent "to a heat sterilization unit 22 by a collected flock return pump 42. The heat sterilization unit 22 sterilizes the microorganisms and bacteria contained within the the flocs collected by heat treatment of the collected flocs.

Note that the collected flocs are in the form of paste. Therefore, it is preferable to use a pump positive displacement, such as a tube pump or a single-axis screw pump, such as the return pump of collected flocs 42. The heating temperature for sterilizing bacteria or the like is set in the range of 75 to 80 ° C and a heating time of about 3 minutes is established.

Meanwhile, the magnetic dust extraction unit 20 includes: compression units 52 and 54 for compressing the collected flocs by shear force; an extraction unit (or extraction device) 56 for selectively extracting the magnetic powder component from the compressed flocs collected by magnetic force and a pump (or return device) 58 to return the extracted magnetic powder component to the supply tube of raw water 12.

As mentioned hereinabove, the flocculation magnetic separator 10 shown in FIG. 1 represents a mode in which the heat sterilization unit 22 is disposed in the upstream position of the return flow of collected flocs which is included. in the return and addition unit 18. Furthermore, in the embodiment, the magnetic dust extraction unit 20 is disposed in the downstream position of the return passage.

The compression unit 52 is an inline mill that generates strong cutting force by rapidly rotating the stirring blade 60 having a special shape. In contrast, another compression unit 54 is a supersonic wave compression device (frequency = about 20 KHz) that generates shear force with a liquid 64 upon immersing a rod-shaped vibrator 62 that vibrates at the frequency of the supersonic wave in the liquid 64.

Note that in the present embodiment two compression units 52 and 54 are arranged, while either one or the other of the units can be arranged. Alternatively, a ball mill 65 can be used as a compression unit (or compression device).

Then, the collected flocs compressed by the compression units 52 and 54 are supplied to an extraction unit 56. The extraction unit 56 extracts the magnetic powder component from the collected flocs crushed by the magnetic force. To such an extraction unit 56, a system using a magnetic disk or a magnetic drum is applied, permanent magnets are embedded in the disk and the drum.

This construction allows the magnetic powder components to be extracted from the collected flocs and for SS substances, other than the magnetic powder component, to be discharged.

Here, the downloaded content of the SS substances different from the magnetic powder component is about 0.2% of the performance of the flocculant magnetic separation device 10. Thus, the extraction unit 56 in the present embodiment can be smaller than the magnetic separation unit 16 which is a main component .

The collected flocs from which the extraction treatment for extracting the magnetic powder component has been completed, are stored in the storage tank of collected flocs (not shown in Figure 1) as separate and collected flocs. This process is similar to the process carried out for an excess of the collected flocs that are generated in the collection tank of collected flocs 50. Note that the magnetic powder component extracted by magnetic force has a low water content, resulting in low capacity flow. By this, the magnetic powder component is supplied to a tank 68 for storing clear water 66, to be diluted thereby therein. After this, the magnetic powder component thus diluted with clear water 66 is returned to the raw water supply tube 12 by pump 58. This process allows high purity magnetic powder to be added to the raw water flowing through the tube of raw water supply 12.

At present, in the raw water supply tube 12, the return position of the collected flocs and the The magnetic powder addition position is located in a region downstream of the SS 40 concentration meter, in a region upstream of the high-speed agitation tank 26 and a region upstream of the place where the flocculant is added. Note that the rotational speed of the pump 58 is controlled by the control unit 24 based on the SS concentration data measured by the SS 40 concentration meter.

Next, the effects of the flocculation magnetic separator 10 constructed as mentioned hereinabove will be explained in detail.

Figure 2 is a schematic block diagram showing a base body of the flocculation magnetic separation device 10. This base body of the flocculation magnetic separation device 10 represents a separator constructed by separating the magnetic powder extraction unit 20 from the device of magnetic flocculation separation 10 shown in Figure 1.

That is, the magnetic flocculation separator 10 of Figure 2 represents a mode in which only the thermal sterilization unit 22 is disposed in the return passage of the collected flocs. In the present, the return process is carried out by the return and addition unit 18.

The magnetic flocculation separator 10 of Figure 2, the return and addition unit 18 is arranged which returns and adds the collected flocs discharged from the magnetic separation unit 16 to a region upstream of the position where the flocculant is added, in the raw water supply pipe 12. collected flocs discharged from the magnetic separation unit 16 are temporarily stored in a collection tank of collected flocs 50 (see Figure 1). Then, the resulting collected flocs are returned to the raw water supply tube 12 by a collected floc return pump 42 included in the return and addition unit 18.

In contrast, collected non-returned flocs are stored separately from a flocked floc storage tank (not shown in Figure 2) by overflowing the flocs of the collected floccule receiving tank 50 as an excess of the floccules.

As mentioned above, the procedure of returning the collected flocs to the raw water supply tube 12 allows the collected flocs to be recycled without using a chemical compound such as hydrochloric acid. As a result, the magnetic powder component contained in the collected flocs allows the used amounts of the newly added magnetic powder to be reduced. In addition, this also allows the total amount of the collected flocs thus generated due to the addition of the newly added magnetic powder is reduced.

Meanwhile, the control device 24 controls the return quantities of the collected flocs carried out by the return and addition unit 18 and the addition amounts of the newly added magnetic powder carried out by the magnetic powder supply unit 30. In the present, this control operation is carried out based on the concentration of SS detected by the SS 40 concentration meter and the maximum concentration of SS in the raw water, the maximum concentration of SS in the raw water having been established in advance.

That is, when the concentration of SS detected by the SS 40 concentration meter is equal to the maximum SS concentration in the raw water, the control unit 24 stops the return operation of the collected flocs carried out by the unit. of return and addition 18. Simultaneously, the control unit 24 controls the addition amounts of the newly added magnetic powder carried out by the magnetic powder supply unit 30.

At that time, as the concentration of SS becomes lower than the maximum SS concentration in the raw water, the control unit 24 increases the return quantities of the collected flocs carried out by the return and addition device 18. Simultaneously, the control unit 24 reduces the addition amounts of the newly added magnetic powder carried out by the magnetic powder supply unit 30.

The aforementioned procedure allows the treatment performance of the flocculation magnetic separator 10 of Figure 2 to be stabilized without being influenced by the concentration of SS in the raw water. Note that a unit with the reference number 70 represents the filter. The filter 70 separates the treated water and wash water from the water to be treated which has been separated by the magnetic separation unit 16. Then, the wash water is returned to the raw water supply pipe 12 through the pipeline 72 Next, more specifically, a control method carried out by the control unit 24 will be explained in detail.

First, note that the return quantities of the collected flocs are controlled by the rotational velocity of the collected flock return pump 40, which is controlled by the control unit 24. In the present, the proportion in the amounts of return of the collected flocs are adjusted in the range of 0 to 100% of the total discharged quantities of the collected flocs.

Secondly, note that the return quantities of the collected flocs are controlled by the control unit 24 based on the SS concentration in the raw water detected by the SS 40 concentration meter together with the maximum SS concentration in the raw water established in advance.

For example, it is assumed that the flocculation magnetic separator 10 is designed to have the maximum SS concentration in raw water of 50 mg / 1. In that case, it is assumed that the raw water having the SS concentration of 50 mg / 1 flows into the raw water supply pipe 12. If 100% of the collected floccules are returned to the raw water, this means that the SS in the amounts corresponding to the SS concentration of 50 mg / 1 it is returned to the raw water. Thus, the concentration of SS in the raw water flowing to the high-speed agitation tank 26 is represented by the following formula: 50 + 50 = 100 mg / 1. By this, the concentration of SS in raw water that has a value of 100 mg / 1 is higher than the maximum SS concentration in raw water that represents the marginal ability made by the magnetic flocculation separator 10.

On the other hand, when the raw water which has the SS concentration of 10 mg / 1 flows into the raw water supply tube 12, the magnetic flocculation separator 10 has sufficient treatment ability to treat the raw water for the ability to treat raw water with the SS concentration of 40 mg / 1 compared to raw water with the SS concentration of 50 mg / 1.

As a result, there is no problem of returning the amount of collected flocs corresponding to the remaining space of the treatment ability of the magnetic flocculation separator 10.

In a test calculation, when the magnetic flocculation separator 10 in Figure 2 is used for the treatment of raw water, the ratio between the concentration of SS of raw water (A) (mg / 1), the returnable amount of the collected flocs (B) (return ratio (%) of the number of flocs collected by the amount of flocs discharged) and the addition amount of the newly added magnetic powder (C) (mg / 1) is shown on a graphical chart of Figure 4 and in Table 1 listed hereinafter.

In the present, the graphical diagram of Figure 4 and Table 1 show a returnable quantity of the flocs collected when the maximum designed SS concentration in raw water is 50 mg / 1.

In the graphical diagram of Figure 4, the vertical axis represents the proportion of the magnetic powder contained in the flocs at the time just before being returned to the magnetic separator unit 16. The horizontal axis represents the Return ratio of the flocs collected by the amount discharged.

In addition, the lowest limited value of the proportion of magnetic powder in the flocs is set at 31.4%. Here, the return ratio of the flocs and the addition amount of the newly added magnetic powder are adjusted in such a way that the proportion of magnetic powder becomes 31.4% or more in order to effectively effect the magnetic separation by the magnetic unit. magnetic separation 16.

Note that the return ratio of the flocs and the amount of addition of magnetic powder newly added are adjusted by 31.4% in the present modality. More specifically, as shown in Table 1, when the concentration of SS in the raw water is 50 mg / 1, the magnetic flocculation separator 10 does not return the collected floccules, while the separator 10 only adds the fresh magnetic powder. added by the concentration of 30 mg / 1. The concentration of SS in raw water is detected by the SS 40 concentration meter and the flocculation magnetic separator 10 controls the return velocity of the collected flocs and the addition amount of the newly added magnetic powder corresponding to the detected data thus measured as shown in table 1.

Furthermore, when the magnetic flocculation separator 10 is applied to a ballast water treatment at maximum SS concentration in raw water it is designed to have a value of 50 mg / l, following the regulations of the IMO. However, since the actual SS concentration in seawater frequently has a value of less than 10 mg / 1, the process of returning the flocs collected to the raw water supply tube 12 as set as mentioned above allows that the quantities used of the newly added magnetic powder are reduced.

This also allows the amounts of storage needed for the newly added magnetic powder to be reduced, resulting in extensively advantageous merits to a ship of which the interior space for disposing multiple devices is significantly limited. Note that plankton and bacteria (individual viable) are adjusted for a removal goal in a ballast water treatment. Accordingly, when the collected flocs are returned to the raw water supply pipe 12, the heat sterilization unit 22 is arranged in a return pipe line, thereby returning the collected flocs as the plankton is sterilized and bacteria Table 1 On the other hand, the newly added magnetic powder injection amounts are controlled by the control device 24 by adjusting the rotational speed of the magnetic powder injection pump 38. Agui, the control operation is carried out in the range of 0 to 100%, in which a rate of 100% (ie, 30 mg / 1) calculated by the injection amount of the newly added magnetic powder represents a case that no collected flock is returned to the raw water supply pipe 12. The injection quantities of the newly added magnetic powder1 are determined by the return quantities of the collected flocs. For example, when the return amount of the flocs collected per quantity discharged is 47%, the magnetic powder flowing into the high-speed agitation tank 26 will be returned in 47% of it. By this, the injection amounts of the powder Newly added magnetic can be adjusted by about 53% (or 16 mg / 1).

The return quantities of the collected flocs are detected by a flow meter 74 which is arranged in the return pipe for the collected flocs. Based on the measurement results of the flow meter 74, the control device 24 adjusts the rotational speed of the pump 38, thereby adjusting the injection amounts of the newly added magnetic powder.

Here, the flocculation magnetic separation device 10 of Figure 2 can not return the collected flocs if the concentration of SS is larger than the maximum designed SS concentration in raw water. Therefore, even in such a case, in order to return the flocs collected to thereby recycle the magnetic powder component in the collected flocs, it is necessary to extract only one component of magnetic powder from the collected flocs and remove other components of SS in the collected flocs. the return process.

Next, the flocculation magnetic separator 10 of FIG. 3 shows the arrangement of the units. Here, a magnetic powder extraction unit 20 is disposed in a downstream position of a magnetic separation unit 16 and a heat sterilization unit 22 is disposed at a position downstream of the magnetic dust extraction device 20.

That is, the magnetic flocculation separator 10 of FIG. 3 represents a mode in which the magnetic powder extraction unit 20 is disposed in an upstream position in a magnetic flock return process; the return process is carried out by the return and addition device 18, while the heat sterilization unit 22 is disposed in a downstream position in the return passage.

The magnetic powder extraction unit 20 separately effects the treatment of collected flocs that have been discharged from the magnetic separation device 16 by means of the following two steps of the steps of: extracting the magnetic powder component contained in the collected flocs and remove other SS components from the collected flocs.

The first stage includes the steps of: compressing the flocs collected by applying physical force to the collected flocs. In the collected flocs, the magnetic powder component and other SS components are strongly agglomerated by an inorganic flocculant and a polymeric flocculant. Thus, an inline mill 52 and / or supersonic wave compression device 54 are used to compress such strongly agglomerated flocs.

Note that it is experimentally determined that the flocs harvested thus agglomerated strongly are decomposed to be almost crushed, via a compression treatment thereof for several 10 seconds to several minutes carried out by the inline mill 52 and / or the supersonic wave compression device 42.

Here, a method for adjusting the pH value using a chemical compound as described in Patent Document 2 can be carried out to facilitate that the collected flocs are decomposed. However, when the treatment is carried out on a ship, it is preferable to decompose the collected flocs via only a physical method, taking into consideration the regulations of the IMO or the like.

The second stage is the steps of: extracting only the magnetic powder component from the flocs collected thus compressed by magnetic force. As extraction unit 51 (see Figure 1), a unit using a magnetic disk or a magnetic drum both with embedded permanent magnets. Then, the second step further includes the steps of: diluting the extracted magnetic powder component with clear water 66 (see figure 1) and returning the magnetic powder component to the raw water supply tube 12 (see figure 1) by the pump 58 (see figure 1).

Although the two stages of the steps, the purity of the magnetic powder component to be returned is increased.

This increase in purity allows collected flocs containing mainly the magnetic powder component to be returned even though the concentration of SS of raw water becomes higher.

Here, a test calculation is carried out assuming the case that the SS components different from the magnetic powder component are separated from 30% of the collected flocs. Thus, in the case of the magnetic flocculation separator 10 of FIG. 3, the relationships between the concentration of SS in the raw water (A) (mg / ml), the returnable quantities of the collected flocs (B) (this is represented by the return ratio of the flocs collected by quantities discharged from the collected flocs) and the addition amounts of the new magnetic powder (C) (mg / 1) are represented by the graphic diagram of Figure 5 and Table 2.

The aforementioned results demonstrate that the flocculation magnetic separator 10 of Figure 3 can further increase the return rate of collected flocs corresponding to the SS concentration in the raw water and reduce the addition amounts of the new magnetic powder than the separator magnetic flocculation 100 that does not have a magnetic dust extraction unit 20 of Figure 2.

Table 2 In addition, if 60% of the SS components other than the magnetic powder contained in the collected flocs are removed and removed from the flocs collected by the magnetic powder extraction unit 20, this results in the condition that the collected flocs they originally contain the concentration of SS in raw water of 30 mg / 1. By this, this SS concentration allows 42% of the collected flocs discharged to be returned.

Thus, it is preferable to arrange the magnetic powder extraction unit 20 in the flocculation magnetic separator 10 if the concentration of SS in raw water is frequently higher than the maximum designed SS concentration in raw water or if more quantities of the flocs collected are returned to reduce the amounts used of the newly added magnetic powder are also reduced.

Additional remarks Explanation regarding the optimal value of the proportion of magnetic powder in magnetic flocs Here, it will be noted that the treatment objectives to treat ballast water include plankton and bacteria. In addition to this, if a ballast water treatment system is installed on a ship, it is necessary to pass a test to verify the performance of the system's treatment or regulations, as defined by the regulatory agency. According to the regulations, it is demanded that the treatment system have sufficient performance to treat the ballast water containing the suspended solids (SS) such as sand in the ballast water with the maximum concentration of 50 mg / 1, satisfying the load criteria in ballast water.

In this regard, the present inventors adopt a method for adding mineral-based microparticles called kaolin as a sand simulator or the like in the test to determine conditions in the magnetic separation of flocculation of plankton and bacteria.

Hereinafter, the test method in detail will be explained more specifically.

First, seawater containing plankton and bacteria is added to the kaolin mentioned above at a concentration of 50 mg / 1. Then, a test of Flocculation of seawater is carried out by adjusting parameters (or variables) to include the proportions of addition of magnetic powder, an inorganic flocculant and a polymeric flocculant. After this, the state of formation of the magnetic flocs is evaluated by visual observation. Next, the seawater containing the magnetic flocs is introduced into a channel in which permanent magnets are placed in order. The seawater was subjected by a contact treatment and an adsorption treatment with the magnets for a predetermined time (or several seconds). Then, the concentration of the magnetic flocs in the sea water discharged from the channel is measured, while the rate of removal of the magnetic flocs is determined.

The results in the evaluation test as mentioned above clearly indicate that the plankton and bacteria are sufficiently flocculated under the condition of the addition ratios: polyaluminium chloride used as inorganic flocculant 5 mg Al / 1 and polymeric flocculant = 1 mg / 1 .

In addition, as shown in Figure 6, the removal of magnetic flocs is likely to increase, as the rate of magnetic powder addition increases. When the rate of magnetic powder addition becomes 30 mg / 1 or more, it is likely that the Removal speed reaches a maximum. From the point of view of cost, it is desirable to decrease the rate of addition of the magnetic powder as much as possible. By this, it is determined that the rate of addition of the magnetic powder is 30 mg / 1.

If the rates of addition of the magnetic powder, the inorganic flocculant and the polymeric flocculant are adjusted to the values as mentioned above, the content of the magnetic powder by magnetic flocs can be calculated by the following formula.

Magnetic powder content in magnetic flocs (%) = (magnetic powder addition rate) / (addition rate of kaolin + magnetic powder addition rate + addition rate of inorganic flocculant + addition rate of polymeric flocculant) x 100 - (Formula 1) .

Here, each value is listed as follows, magnetic powder addition rate = 30 mg / 1, - rate of addition of kaolin = 50 mg / 1; addition rate of inorganic flocculant = 5 x (78/27) = 14.4 mg / 1; polymeric flocculant addition rate = 1 mg / 1.

Note that the added polyaluminium chloride as an inorganic flocculant exists in the form of aluminum hydroxide (A1 (0H) 3) in the magnetic flocs. Therefore, the rate of addition of polyaluminium chloride is calculated by the formula of: 5 mg Al / L (addition rate) x 78 (MW of A1 (0H) 3) / 27 (AW of Al).

If the respective values are substituted in formula 1, the formula is represented as: Magnetic powder content in magnetic flocs (%) = 30 / (50 + 30 + 14.4 + 1) x 100 = 31.4 (%) The present inventors determine that this calculated speed of the magnetic powder is the optimum value that allows the removal velocity of the magnetic flocs to be assured and the treatment costs to be minimized.

As mentioned hereinabove, it should be noted that a method of magnetic powder recycling needs to construct a magnetic powder treatment flow to ensure the velocity of removal of magnetic flocs and to have the performance of the magnetic treatment without decreasing the content of the magnetic flock. magnetic powder less than the value as calculated above.

In addition, a graphic diagram in figure 7 shows the return velocity of the flocs collected by SS in raw water (mg / 1). The return speed of the collected flocs is adjusted based on the graph.

DESCRIPTION OF REFERENCE NUMBERS 10: Magnetic flocculation separator 12: Raw water supply pipe 14: Flocculation unit 16: Magnetic separation unit (or magnetic separation device) 18: Return and addition unit (or return and addition device) 20: Magnetic dust extraction unit (or magnetic dust extraction device) 22: Thermal sterilization unit (or heat sterilization device) 24: Control unit (or control device) 26: High-speed agitation tank (or first agitation tank) 28 Low speed agitation tank (or second agitation tank) 30: Magnetic powder supply unit (or magnetic powder supply device) 32: Flocculant addition unit 34: Pipe 36: Polymer flocculant addition unit '.. 38: Magnetic powder injection pump 40: SS concentration meter (or concentration detection device) 42: Pump of return of collected flocs 44: Magnetic separation tank 46: Magnetic filter 48: Transporter 50: Collecting tank of collected flocs 52: Compression unit (or compression device: in-line mill) 54 Compression unit (or compression device: supersonic wave shredder) 56: Extraction unit (or extraction device) 58: Pump (or return device) 60: Stirring blade 62: Vibrator 64: Liquid 65: Ball mill (compression unit) 66: Clear water 68: Tank 70: Filter 72: Pipe 74: Flow meter

Claims (5)

1. A magnetic flocculation separator, characterized in that it comprises: a first agitation tank that is connected to a raw water supply pipe that supplies raw water and to rapidly stir the added raw water with a flocculant and magnetic powder that is supplied from a magnetic supply device, thereby forming magnetic microflocks containing the magnetic powder; a second agitation tank to stir more slowly the treated water to which a polymeric flocculant is added than the first agitation tank, to thereby expand the magnetic microfloc, the treated water contains the magnetic microfloc and is discharged from the first stirring tank; a magnetic separation device for collecting magnetic flocs enlarged by magnetic force of the raw water that is discharged from the second agitation tank and contains the enlarged magnetic flocs and a return and addition device for returning the collected flocs that have been collected by the magnetic separation device to the raw water supply tube in a position upstream of the first agitation tank and in an upstream position where the Flocculant is added, to add the collected flocs to the raw water.

2. The magnetic flocculation separator as described in claim 1, characterized in that it also comprises: a concentration detection device for detecting the concentration of suspended solids in the raw water, in an upstream position where the magnetic powder, the flocculant and the flocs collected are aggregated and a control device for controlling the return quantities of collected flocs driven by the return and addition device and addition amounts of the magnetic powder driven by the magnetic powder supply device, based on both the concentration of suspended solids detected by the concentration detection device and the maximum concentration of suspended solids in the raw water established in advance.

3. The magnetic flocculation separator as described in claim 2, characterized in that the control device stops the process of returning the collected flocs carried out by the return and addition device, when the concentration of the suspended solids detected by the device concentration detection is equal to the maximum concentration of the solids suspended in raw water and simultaneously the control device controls the addition amounts of the magnetic powder driven by the magnetic powder supply device and the control device increases the return quantities of collected flocs driven by the return and addition device, as the concentration of the suspended solids becomes lower than the maximum concentration of suspended solids in raw water and simultaneously the device of control decreases the addition amounts of the magnetic powder driven by the magnetic powder supply device.

4. The magnetic flocculation separator as described in claim 1, characterized in that it also comprises: a magnetic dust extraction device that is disposed in a return pipe located between the return and addition device and the raw water supply pipe; The magnetic dust extraction device comprises: a compression device for crushing the collected flocs by shear force; an extraction device to selectively extract only the magnetic powder component of the flocs collected thus compressed by using magnetic force and a return device to return the extracted magnetic powder component to the raw water supply tube.

5. The magnetic flocculation separator as described in claim 1, characterized in that it further comprises a sterilization device for sterilizing plankton and bacteria contained in the collected flocs, arranged in a return pipe of the collected flocs driven by the return and addition device .