JP2009000583A - Ballast water treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ballast water treatment apparatus and method which surely and inexpensively satisfy ballast water standards establish by IMO when using water of any quality. <P>SOLUTION: The ballast water treatment apparatus comprises a sterilizer feeder 5 feeding a sterilizer into seawater, a Venturi tube 6 receiving feeding of the sterilizer-fed seawater and generating cavitation in the seawater to diffuse the sterilizer in the seawater and to damage or kill aquatic organisms in the seawater, and a sterilizer feed amount controller 31 measuring a sterilizer concentration in the seawater discharged from the Venturi tube 6 to obtain an average value of the sterilizer concentrations at a predetermined time, and adjusting a feed amount of the sterilizer fed from the sterilizer feeder so as to equalize the feed amount to an amount obtained by multiplying a sterilizer feed amount corresponding to a target sterilizer concentration by a dead zone control ratio when the average value of the sterilizer concentrations deviates from the dead zone range of a predetermined sterilizer concentration. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an apparatus for treating ballast water loaded in a ballast tank of a ship, and more particularly to an apparatus for efficiently killing harmful bacteria and plankton contained in ballast water.

In general, a ship with an empty load or a small load will inject ballast water into the ballast tank before leaving the port because of the necessity of ensuring the depth of the propeller submersion and ensuring safe navigation when empty. Conversely, when loading in the port, the ballast water is discharged.
By the way, when ballast water is poured and drained by a ship that goes back and forth between loading and unloading ports in different environments, there is a concern that it may adversely affect the coastal ecosystem due to the difference in microorganisms contained in the ballast water. Has been.
Therefore, an international convention for the regulation and management of ship ballast water and sediment was adopted in February 2004 at an international conference on ship ballast water management, which required the treatment of ballast water.

The standard established by the International Maritime Organization (IMO) as a standard for the treatment of ballast water is that the number of organisms (mainly zooplankton) of 50 μm or more contained in the ballast water discharged from the ship is less than 10 in 1 m ³ , 10 μm or more The number of organisms less than 50 μm (mainly phytoplankton) is less than 10 in 1 ml, the number of Vibrio cholerae is less than 1 cfu in 100 ml, the number of E. coli is less than 250 cfu in 100 ml, and the number of enterococci is 100 cfu in 100 ml It is less than.

As ballast water treatment technology, a filtration device that filters seawater to trap aquatic organisms, a bactericide supply device that supplies bactericides that kill bacteria in the seawater into the filtered seawater, and a bactericide supply And a venturi tube that receives a supply of filtered water and generates cavitation in the filtered water to diffuse the disinfectant in the filtered water and damage or kill aquatic organisms in the filtered water. It has been proposed (see, for example, Patent Document 1).
International Publication WO2006 / 132157

In the method described in Patent Document 1, it is disclosed to kill bacteria in seawater using sodium hypochlorite or the like as a bactericidal agent. However, in order to reduce processing costs, a bactericidal agent is used as much as possible. It is preferable to suppress the amount and to use the minimum necessary amount.
For this reason, it is necessary to adjust the concentration of the bactericide so as not to be excessively supplied by detecting the concentration of the bactericide in the seawater to obtain an appropriate concentration.
However, due to clogging of filters arranged in the processing path, fluctuations in the supply flow rate to the ballast tank, etc., the residual concentration of the bactericide may differ even when the same amount of bactericide is supplied.
In addition, time delays such as the time from supply of a bactericidal agent to diffusion into seawater and the time until the bactericidal agent exhibits a bactericidal effect (the time until free chlorine is generated in sodium hypochlorite). There is also.
For this reason, there is a problem that proper supply amount control is difficult in general feedback (PID) control.

  In order to adjust the supply amount of the bactericidal agent, it is necessary to adjust the output of the pump for supplying the bactericidal agent and the opening degree of the valve provided in the bactericidal agent supply line. If the concentration of the sterilizer is adjusted to be higher or lower than the predetermined sterilizer concentration and the sterilizer supply amount is adjusted, the pump output and valve opening must be adjusted frequently. Failure may occur.

  This invention is made | formed in order to solve this subject, and it aims at providing the processing apparatus of the ballast water which can control appropriately the supply_amount | feed_rate of a disinfectant | microbicide, without causing a malfunction to an apparatus used.

(1) A ballast water treatment apparatus according to the present invention includes a bactericidal agent supply device that supplies bactericidal agent into seawater, and receives the supply of seawater supplied with bactericidal agent to generate cavitation in the seawater. Venturi that diffuses the fungicide and damages or kills aquatic organisms in seawater, and measures the concentration of the fungicide in the seawater discharged from the venturi, and averages the concentration of the fungicide for a predetermined time When the average value of the bactericidal agent concentration deviates from a predetermined dead zone range of the bactericidal agent concentration, the bactericidal agent supply amount supplied by the bactericidal agent supply device is determined according to the target bactericide concentration. A bactericide supply amount control device that adjusts the supply amount by multiplying the bactericidal agent supply amount by a dead zone control rate Rn _expressed by equation (1).
R _n = R _n−1 + (x _s −x _ave ) · a · w (1)
R _n ; dead zone control rate R _n-1 ; dead zone control rate x _s ; previous bactericidal agent concentration target value x _ave ; bactericidal agent concentration average value a; predetermined coefficient w; dead zone control width

  By providing the above-described configuration, marine aquatic organisms and bacteria in seawater can be killed or removed, ship ballast water not containing pests can be supplied, and the supply amount of the bactericide can be controlled appropriately. The main functions of each component are as follows, and the function of each component acts organically to enhance the killing effect of plankton and bacteria in seawater.

(i) Disinfectant The disinfectant supplied to the seawater processed by the disinfectant supply device kills bacteria in the seawater. As a disinfectant to be supplied, sodium hypochlorite, chlorine, chlorine dioxide, hydrogen peroxide, ozone, peracetic acid, or a mixture of two or more of these can be used.
(ii) Venturi tube Venturi tube causes cavitation to occur in seawater supplied with a bactericide, causing damage or death to relatively small aquatic organisms such as phytoplankton. Further, the sterilizing agent is rapidly diffused into seawater by cavitation to promote the sterilizing action of bacteria by the sterilizing agent.
In this way, since the mixing of the sterilizing agent into the seawater is promoted by the diffusion action of cavitation by the venturi tube, the supply amount of the sterilizing agent can be reduced as compared with the case where only the sterilizing agent is injected. For this reason, the influence on the environment by a disinfectant can be reduced, and supply of a disinfectant decomposer for rendering the disinfectant harmless can be eliminated or reduced.

(iii) Disinfectant supply device The disinfectant supply device supplies a disinfectant that kills bacteria to seawater supplied to the Venturi tube. The sterilizing agent supply device is provided with a sterilizing agent storage tank for storing the sterilizing agent, a pipe for supplying the sterilizing agent in the sterilizing agent storage tank to the venturi pipe side, and is provided on the distal end side of the pipe to inject the sterilizing agent into the supply destination. It has an inlet, a supply pump for supplying the sterilant in the sterilant storage tank to the venturi pipe side, a valve for adjusting the supply amount of the sterilizer, and the like.

The disinfectant supply device supplies disinfectant upstream of the venturi and / or to the throat of the venturi. When supplying the bactericidal agent to the upstream side of the venturi pipe, the bactericidal agent is diffused to some extent in the pipe before reaching the throat of the venturi pipe where cavitation occurs, and then the diffusion and mixing of the bactericidal agent are advanced by cavitation. Furthermore, since the penetration of the fungicide into the bacteria can be promoted, the killing effect of the fungicide can be promoted.
In order to supply the bactericidal agent to the upstream side of the venturi pipe, a bactericidal agent inlet may be provided on the straight pipe upstream of the venturi pipe.
Further, when supplying the sterilizing agent to the throat of the venturi pipe, the supply pump is not necessary because the self-priming is performed by the ejector action of the venturi pipe.

(iv) Disinfectant supply amount control device The disinfectant supply amount control device is a measuring device for measuring the concentration of disinfectant in seawater discharged from the venturi pipe, storage means for storing various data, and disinfectant supply amount. And a control means for controlling the device based on the calculation result of the calculation means.
The measuring device measures the concentration of the bactericide in the seawater discharged from the venturi pipe and outputs it to the calculation means.
Data shown in the following (a) to (c) is stored in the storage means.
(A) Bactericide concentration target value (x _s ) determined in advance as a minimum concentration target value of a bactericide necessary for killing bacteria in seawater
(B) A dead band range (x _s (1−c _L ) ≦ dead band range ≦ x _s (1 + c _H ), which is predetermined as an upper and lower limit range of the bactericide concentration that can be allowed with respect to the target value of the bactericide concentration.
c _L ; dead zone lower limit width (for example, greater than 0 and less than 0.20)
c _H : Deadband upper limit width (for example, greater than 0 and less than 0.50)
In some cases, c _L and c _H are equal.
(C) Predetermined relational expression (y = ax + b, a; predetermined coefficient (slope) as a relation between the bactericidal agent supply amount (y) and the bactericidal agent concentration (x), a number greater than 0 and less than 1 B; intercept, a number greater than 0 and less than 1)
The above relational expression takes into account the conditions that affect the process until the supplied bactericidal agent is diffused and becomes effective as an effective bactericidal component, and the bactericidal agent supply amount (y) and bactericidal agent concentration (x) The relationship is established.
Incidentally, bactericide supply amount _{y s} for fungicides density target value _{x s becomes} y s = _ax s + b.

The calculation means inputs the measurement result of the measuring device and obtains the average value of the bactericide concentration for a predetermined time. Then, it is determined whether or not the average value of the bactericidal agent concentration deviates from the upper and lower limit range (dead zone range) of the bactericidal agent concentration that can be allowed with respect to the bactericidal concentration target value. The sterilizing agent supply amount to be calculated is calculated based on the data stored in the storage means.
The control means performs adjustment control of the output of the supply pump and the like and / or the opening of the supply amount adjustment valve based on the calculation result of the calculation means.
The control procedure is as follows.

<Procedure control procedure>
Every time a predetermined time elapses, the measuring device measures the concentration of the bactericide in the seawater discharged from the venturi pipe, and outputs the measurement result to the calculation means.
The calculation means inputs the measurement result and obtains the bactericide concentration average value x _ave for a predetermined time. Then, it is determined whether or not this germicide concentration average value x _ave deviates from a predetermined dead zone range of the germicide concentration, and when it is deviated, the germicide supply amount y is set as a target germicide concentration. The sterilizing agent supply amount y (y = y _s · R _n ) obtained by multiplying the sterilizing agent supply amount y _s by the dead zone control rate R _n is obtained.
By adjusting the bactericidal agent supply amount so as to obtain the obtained bactericidal agent supply amount y, the bactericidal agent concentration average value x _ave exceeds the upper and lower limit ranges of the bactericidal agent concentration that can be allowed for the bactericidal agent concentration target value. If so, the bactericide concentration average value x _ave is adjusted to fall within the upper and lower limits.
Note that the dead zone control rate R _n is expressed by the equation (1).
R _n = R _n−1 + (x _s −x _ave ) · a · w (1)
R _n-1 : Dead band control rate before 1 time a: Predetermined coefficient (greater than 0 and less than 1)
w: Dead band control width (greater than 0 and less than 1)

  When the sterilizing agent supply amount y is obtained, the control means inputs the obtained sterilizing agent supply amount y, and outputs and / or supplies such as the rotation speed of the supply pump so as to obtain the obtained sterilizing agent supply amount. Performs adjustment control of the opening of the quantity adjustment valve.

According to the present invention, in order to adjust the supply amount of the bactericide based on the average value of the bactericide concentration for an appropriate time, there is a change in the residual concentration of the bactericide or the time for supplying the bactericide and diffusing into the seawater Even if there is a time delay such as the time until the bactericidal agent exhibits a bactericidal effect, the amount of bactericidal agent supplied can be accurately controlled.
Further, an upper and lower limit range of the sterilizing agent concentration that can be allowed with respect to the sterilizing agent concentration target value is determined in advance as a dead zone range, and when the dead zone is deviated, an operation for adjusting the sterilizing agent supply amount is performed. Therefore, it is not necessary to frequently adjust the output such as the rotation speed of the supply pump and the opening degree of the valve, and it is difficult for each device to be defective.

(2) Moreover, in the thing as described in said (1), a bactericidal agent supply amount control apparatus measures the seawater flow volume processed, calculates | requires the flow rate average value of predetermined time, and uses the said bactericide supply amount as said flow rate average value. It adjusts according to this, It is characterized by the above-mentioned.
When the seawater flow rate fluctuates, it is necessary to correct the disinfectant supply amount. However, if an attempt is made to control the supply amount of the bactericidal agent based only on the residual concentration of the bactericidal agent, a time delay such as the time for supplying the bactericidal agent to diffuse into the seawater or the time for the bactericidal agent to exert a bactericidal effect There are cases where proper control is not possible.
Therefore, by performing control in consideration of fluctuations in the seawater flow rate, it is possible to control the supply amount of the sterilizing agent more appropriately.
Specifically, the disinfectant supply amount y is adjusted based on the following formula.
y = y _s · R · (Q _ave / Q _s )
Q _ave ; flow rate average value Q _s ; reference flow rate In the present invention, since the bactericidal agent supply amount is corrected according to the fluctuation of the seawater flow rate, the bactericidal agent supply amount can be controlled more accurately.
The average flow rate is an average flow rate for a predetermined time. Further, the reference flow rate is seawater flow rate when determining the sterilizing agent supply amount y _s corresponding to disinfectant concentration as a target.

(3) In addition, in the above-described (1) or (2), a bactericide decomposer supply device that supplies a bactericide decomposer to seawater supplied with a bactericide, and a bactericide concentration remaining in the seawater And a bactericide decomposer supply amount control device that adjusts the bactericide decomposer supply amount of the bactericide decomposer supply device based on the measured residual bactericide concentration. It is.

  By providing such a sterilizing agent decomposing agent supply device, the sterilizing agent remaining in the seawater can be decomposed and the influence on the sea area where the ballast water is discharged can be eliminated. Moreover, by providing the bactericide decomposition agent supply amount control device, the bactericide decomposition agent supply amount can be appropriately adjusted according to the concentration of the bactericide remaining in the seawater.

The disinfectant supply agent control device is a measuring device that measures the concentration of residual disinfectant in seawater discharged from the ballast tank, storage means that stores various data, and an operation that calculates the disinfectant supply amount. Means and control means for controlling the device based on the calculation result of the calculation means.
The storage means includes a supply amount (z) of a disinfectant necessary for decomposing the disinfectant in seawater discharged from the ballast tank, and a disinfectant concentration (x) in seawater discharged from the ballast tank. (Z = cx + d, c; predetermined coefficient (slope), d: intercept).

In the disinfectant decomposition agent supply amount control device configured as described above, the measuring device measures the residual disinfectant concentration in the seawater discharged from the ballast tank. And a calculating means inputs the measured value of a measuring device, and calculates _| requires the residual disinfectant density _| concentration average value _xave of predetermined time. Then, the calculating means calculates the disinfectant disinfectant supply amount (z) corresponding to the residual disinfectant concentration average value x _ave based on the relational expression stored in the storage means. The control means adjusts and controls the sterilizing agent decomposing agent supply pump and the valve opening of the sterilizing agent decomposing agent supply device based on the sterilizing agent decomposing agent supply amount (z) calculated by the calculating means.

  Sodium sulfite, sodium bisulfite (sodium hydrogen sulfite), and sodium thiosulfate can be used as the disinfectant decomposing agent supplied to chlorine disinfectants such as sodium hypochlorite and chlorine. Enzymes such as sodium sulfite, sodium bisulfite (sodium hydrogen sulfite), sodium thiosulfate, and catalase can be used as the disinfectant decomposer supplied to hydrogen oxide.

(4) In the above (3), the bactericide disinfectant supply amount control means measures the flow rate of seawater to be processed to obtain a flow rate average value for a predetermined time, and based on the flow rate average value, the bactericide The decomposition agent supply amount is adjusted.
When the flow rate of the seawater to be processed fluctuates, it is necessary to correct the supply amount of the disinfectant decomposer. Therefore, in the present invention, the disinfectant decomposition agent supply amount z ′ is adjusted based on the following equation.
z ′ = z · (Q _ave / Q _s )
Q _ave : flow rate average value Q _s : reference flow rate In the present invention, since the bactericidal agent decomposing agent supply amount is corrected according to fluctuations in the seawater flow rate, the bactericidal agent decomposing agent supply amount can be controlled more accurately.
The average flow rate is an average flow rate for a predetermined time. Further, the reference flow rate is a flow rate of seawater when obtaining the disinfectant disinfectant supply amount z _s corresponding to the reference residual disinfectant concentration.

(5) Moreover, the thing in any one of said (1)-(4) WHEREIN: The filtration apparatus which filters seawater and capture | acquires aquatic organisms was provided in the upstream of the said disinfectant supply apparatus. It is what.
In order to capture and remove relatively large aquatic organisms such as zooplankton in seawater with a filtration device, supply a bactericidal agent necessary to kill relatively small aquatic organisms such as phytoplankton and bacteria. The supply amount of the bactericidal agent can be reduced, the influence on the environment can be reduced, and the supply of the bactericidal agent decomposing agent for detoxifying the bactericidal agent can be made unnecessary or reduced.

In the present invention, in order to adjust the supply amount of the bactericide based on the average value of the bactericide concentration for an appropriate time, there is a change in the residual concentration of the bactericide, Even if there is a time delay such as the time until the bactericidal agent exhibits the bactericidal effect, the bactericidal agent supply amount can be controlled with high accuracy.
Further, an upper and lower limit range of the sterilizing agent concentration that can be allowed with respect to the sterilizing agent concentration target value is determined in advance as a dead zone range, and when the dead zone is deviated, an operation for adjusting the sterilizing agent supply amount is performed. Therefore, it is not necessary to frequently adjust the output of the supply pump, such as the rotation speed, and the opening of the valve, so that problems such as the supply pump are less likely to occur.

[Embodiment 1]
Hereinafter, an example of the best mode of the ballast water treatment apparatus according to the present invention will be specifically described with reference to the drawings.
FIG. 1 is a block diagram showing a ballast water treatment apparatus according to the first embodiment of the present invention.
The ballast water treatment device of the present embodiment includes a seawater intake line 1, a coarse filtration device 2, a pump 3, a filtration device 4, a bactericidal agent supply device 5, a venturi pipe 6, and a bactericide decomposing agent supply. A device 7, a sterilized water supply line 8, a ballast tank 9, a sterilizing agent decomposition processing line 11, and a sterilizing agent decomposition processing water drain line 12 are provided.

The detoxification treatment of ballast water is based on the amount of microorganisms inhabiting the area of the water to be taken and the operating conditions of the ship, when the ballast water is loaded into the ballast tank, at the time of drainage, or both. Can be determined by.
In the following description, when the ballast water is loaded, the biocidal process is performed in the seawater, and the ballast water stored in the ballast tank 9 is supplied when the ballast water is discharged, and the disinfectant is supplied to the ballast water. A case where the disinfectant is decomposed and discharged into the sea will be described.
First, each component used in this case will be described in detail.

  The seawater intake line 1 takes seawater into the ship. The coarse filtration device 2 removes coarse substances in the seawater taken from the seawater intake line 1. The pump 3 takes in seawater or discharges ballast water in a ballast tank 9 described later into the sea through a disinfectant disinfectant supply device 7 described later.

  The filtration device 4 removes planktons present in the seawater from which coarse substances have been removed by the coarse filtration device 2. The disinfectant supply device 5 supplies the disinfectant to the seawater filtered by the filter device 4 to kill bacteria and plankton. The venturi 6 introduces seawater (filtered water) to which a bactericidal agent is added, generates cavitation in the seawater, damages or kills aquatic organisms in the seawater, and disinfects the bactericidal agent supply device 5. Disperse the disinfectant supplied in the seawater.

The sterilized water supply line 8 sends the seawater after the biocidal process discharged from the venturi 6 to a ballast tank 9 described later. The ballast tank 9 stores seawater after the biocidal treatment sent from the sterilized treated water feed line 8 as ballast water. The disinfectant decomposition processing line 11 sends the ballast water in the ballast tank 9 to the disinfectant disinfectant supply device 7 by the pump 3.
The disinfectant decomposer supply apparatus 7 supplies the disinfectant decomposer to the ballast water in which the disinfectant remains. The sterilizing agent decomposition treatment water drain line 12 is supplied with the sterilizing agent decomposing agent and discharges the ballast water after the sterilizing agent decomposing process to the sea.
Hereinafter, each device will be described in more detail.

1. Coarse filter device Coarse filter device 2 receives water from a sea chest (seawater inlet) provided on the side of the ship and is taken by seawater intake line 1 by pump 3 and contains various small and large contaminants and aquatic organisms. Among them, coarse materials of about 10 mm or more are removed.
As the coarse filtration device, a cylindrical strainer (strainer) having a hole of about 10 mm, a hydrocyclone that separates coarse matter in the water flow by the difference in specific gravity, a device that captures and collects the coarse matter with a rotating screen, etc. are used. be able to.

2. Filtration device The filtration device 4 removes planktons present in the seawater from which coarse substances have been removed by the coarse filtration device 2, and has a mesh size of 10 to 200 μm.
The reason why the mesh opening is 10 to 200 μm is to reduce the frequency of backwashing and shorten the ballast water treatment time in the port of call while keeping the capture rate of zooplankton and phytoplankton at a certain level. In other words, if the mesh size is larger than 200 μm, the capture rate of zooplankton and phytoplankton is remarkably reduced. If the mesh size is smaller than 10 μm, the frequency of backwashing increases and the ballast water treatment time at the port of call becomes longer. Therefore, it is not preferable. In particular, it is preferable to use a material having an opening of about 20 to 35 μm because the capture rate and the backwashing frequency can be set optimally.
Moreover, the filtration device 4 is preferably 1 day 200 meters ³ or more filtration rate per filtration area 1 m ² is obtained. However, there is no particular limitation when the size can be further reduced by integrating the filtration modules.

As a specific example of the filtration device 4, it is preferable to use a notch wire filter or a wedge wire filter.
A notch wire filter is a cylindrical element in which a wire with a notch (protrusion) is wound around a frame and the distance between the wires is maintained by the notch so that the size of the filtration passage is 10 to 200 μm. , Provided with valves and piping for water supply and backwashing. A specific example of this notch wire filter is a notch wire filter manufactured by Kanagawa Kikai Kogyo.
Japanese Laid-Open Patent Publication No. 2001-170416 discloses a plurality of notch wire filters as filtration elements and backwashing means. By attaching a small ultrasonic vibrator to the filtration element assembly substrate and each filtration element and adding ultrasonic vibration during backwashing, the backwashing effect is increased and the backwashing interval is extended to increase the filtration efficiency. Can do.
A wedge wire filter is a tubular element that has a triangular cross-section wound around a frame and adjusts the distance between the wires to maintain a filtration passage size of 10 to 200 μm in the casing. A valve and piping are provided. As a specific example of this wedge wire filter, there is a wedge wire filter manufactured by Toyo Screen Industries.

Another preferred specific example of the filtration device 4 is a laminated disk type filter. A laminated disk type filter is a ring-shaped disk formed by pressing doughnut-shaped disks having a plurality of oblique grooves formed on both sides in an axial direction to form a ring, and a gap formed by grooves of adjacent disks. The aquatic organisms are filtered through the water. By appropriately setting the size of the oblique grooves, the openings are set to 10 to 200 μm and filtered.
In the laminated disk type filter, the disk pressure is released during backwashing to increase the gap and remove the filtration residue.
A specific example of this laminated disk type filter is Spin Klin Filter Systems manufactured by Arkal Filtration Systems.
In addition to the two types of filtration devices described above, other various filtration devices such as a sealed sand filter, a filter cloth filter, and a metal fiber filter can be used as the filtration device 4.

3. Disinfectant supply device The disinfectant supply device 5 supplies the disinfectant that kills bacteria to the seawater filtered by the filtration device 4 and supplied to the venturi tube 6.
As shown in FIG. 2, the disinfectant supply device includes a disinfectant storage tank 21 for storing disinfectant, a pipe 23 for supplying the disinfectant in the disinfectant storage tank 21 to the venturi pipe side, and a distal end side of the pipe 23. It is provided with an inlet 25 for injecting a sterilizing agent into a supply destination, a supply pump 27 for supplying the sterilizing agent in the sterilizing agent storage tank to the venturi pipe side, a valve 29 for adjusting the supply amount of the sterilizing agent, and the like. .
As the disinfectant to be supplied, chlorine, chlorine dioxide, sodium hypochlorite, hydrogen peroxide, ozone, peracetic acid or a mixture of two or more of these can be used, but other disinfectants can also be used. It is.

In addition, when using sodium hypochlorite as a disinfectant, it is preferable to supply so that the weight concentration of the amount of effective chlorine in seawater may be 1-100 mg / l.
The reason is that if the weight concentration of effective chlorine is less than 1 mg / l, hypochlorous acid will not remain after reacting with reducing substances and organic substances in water, and if it exceeds 100 mg / l, corrosion problems and hypochlorous acid will not occur. This is because there is a problem that the storage tank for sodium acid is large and the cost is high, resulting in problems.

The disinfectant is supplied to the upstream side of the venturi 6 and / or the throat of the venturi 6. When supplying the disinfectant to the upstream side of the venturi 6, disinfect the disinfectant to some extent in the tube until it reaches the throat of the venturi tube where cavitation occurs, and then proceed with diffusion and mixing of the disinfectant by cavitation. Furthermore, the disinfecting effect of the disinfectant can be promoted by promoting the penetration of the disinfectant into the bacteria.
In order to supply the bactericidal agent to the upstream side of the venturi pipe 6, a bactericidal agent inlet may be provided on the straight pipe upstream of the venturi pipe 6.
Further, when the sterilizing agent is supplied to the throat portion of the venturi pipe 6, it is self-primed by the ejector action of the venturi pipe 6, so that a supply pump becomes unnecessary.
The disinfectant supply device 5 is controlled by the disinfectant supply amount control device 31 shown in FIG. 2, and an appropriate amount of disinfectant is supplied to a predetermined location.

3-1. Disinfectant supply amount control device The disinfectant supply amount control device 31 measures the disinfectant concentration meter 33 for measuring the disinfectant concentration in the seawater discharged from the venturi tube 6 and the flow rate of the seawater discharged from the venturi tube 6. A flow meter 35, a storage unit 37 for storing various data, a calculation unit 39 for calculating the bactericidal agent supply amount, and a control unit 41 for controlling the apparatus based on the calculation result of the calculation unit 39. Yes.
The disinfectant concentration meter 33 measures the disinfectant concentration in the seawater discharged from the venturi pipe 6 and outputs it to the calculation means 39. The flow meter 35 measures the flow rate of the seawater discharged from the venturi pipe 6 and outputs it to the computing means 39.

The storage unit 37 stores the following data (a) to (c).
(A) Bactericide concentration target value (x _s ) determined in advance as a minimum concentration target value of a bactericide necessary for killing bacteria in seawater
(B) A dead band range (x _s (1−c _L ) ≦ dead band range ≦ x _s (1 + c _H ), which is predetermined as an upper and lower limit range of the bactericide concentration that can be allowed with respect to the target value of the bactericide concentration.
c _L ; dead zone lower limit width (for example, greater than 0 and less than 0.20)
c _H : Deadband upper limit width (for example, greater than 0 and less than 0.50)
In some cases, c _L and c _H are equal.
The reason why the range of the dead zone lower limit width c _L is made smaller than the range of the dead zone upper limit width c _H is to increase the lower limit of the concentration of the bactericide so as to ensure that the organism killing process is performed.
(C) Predetermined relational expression (y = ax + b, a; predetermined coefficient (slope) as a relation between the bactericidal agent supply amount (y) and the bactericidal agent concentration (x), a number greater than 0 and less than 1 ; Predetermined coefficient, b; intercept, number greater than 0 and less than 1)
The above relational expression takes into account the conditions that affect the process until the supplied bactericidal agent is diffused and becomes effective as an effective bactericidal component, and the bactericidal agent supply amount (y) and bactericidal agent concentration (x ).
Incidentally, bactericide supply amount _{y s} for fungicides density target value _{x s becomes} y s = _ax s + b.

The calculation means 39 inputs the measurement result of the bactericide concentration meter 33 and obtains the bactericide concentration average value for a predetermined time. In addition, the measurement result of the flow meter 35 is input to obtain the average flow rate value for a predetermined time.
Further, it is determined whether or not the average value of the bactericidal agent concentration deviates from the upper and lower limit ranges of the bactericidal agent concentration that can be allowed with respect to the target bactericidal agent concentration value. And when it has deviated, the bactericidal agent supply amount which should be supplied is calculated based on the data memorize | stored in the memory | storage means 37. FIG. A specific method of calculating the bactericidal agent supply amount will be described later.
The control means 41 controls the output of the supply pump 27 and / or the opening of the supply amount adjusting valve 29 based on the calculation result of the calculation means 39.

4). Venturi tube Venturi tube 6 causes organisms that have passed through filtration device 4 to be damaged or killed by cavitation generated by the venturi tube, and disinfects the disinfectant supplied from disinfectant supply device 5 into seawater. It is.
The Venturi pipe 6 is composed of a throttle portion where the pipe cross-sectional area gradually decreases, a throat portion which is the minimum cross-sectional area portion, and a widened portion (diffuser portion) where the pipe cross-sectional area gradually increases. Cavitation bubbles are generated by a rapid decrease in static pressure accompanying a rapid increase in flow velocity at the throat, and the cavitation bubbles that have grown due to a rapid increase in pressure accompanying a decrease in flow velocity at the spreading portion are rapidly collapsed. Aquatic organisms in seawater are damaged or destroyed by the action of OH radicals with impact pressure, shearing force, high temperature, and strong oxidizing power due to the collapse of cavitation bubbles.
According to the cavitation of the Venturi tube 6, the outer shell of the protozoan and zooplankton having a relatively hard shell can be destroyed and killed.

  In addition, cavitation is generated by the Venturi tube 6 to cause damage or death to relatively small aquatic organisms such as phytoplankton, and the fungicide is rapidly diffused into the seawater by cavitation, so that the bacteria by the fungicide Promotes the bactericidal action of In this way, mixing of the bactericidal agent into seawater is promoted by the diffusion action of cavitation, so the supply amount of the bactericidal agent can be reduced compared to the case of simply injecting the bactericidal agent, and the influence on the environment can be reduced. Further, it is possible to eliminate or reduce the supply of the disinfectant disinfectant for detoxifying the disinfectant.

In addition, when supplying seawater to the venturi pipe 6, it is preferable to feed the seawater so that the flow rate of seawater at the throat of the venturi pipe 6 is 10 to 40 m / sec.
The reason for this is that when a ballast water treatment device is installed in the middle of a pipe that takes seawater and passes it to the ballast tank, the flow rate of seawater in the pipe is usually 2 to 3 m / s at the venturi pipe entrance. When the flow velocity at the throat of the pipe is less than 10 m / sec, the rate of increase in the flow velocity at the throat is not sufficient, and the rapid decrease in static pressure associated therewith is not sufficient, so that cavitation does not occur even under atmospheric pressure. On the other hand, if the flow velocity at the venturi pipe throat is greater than 40 m / s, the cavitation phenomenon will occur excessively, the pressure loss associated with the passage through the venturi pipe will be excessive, and the energy consumed for water supply will be excessive, so the pump power will be excessive. This is because the cost becomes high.

5). Disinfectant decomposer supply device The disinfectant decomposer supply device 7 detoxifies the disinfectant by supplying the disinfectant decomposer to the seawater to which the disinfectant is added to decompose the disinfectant remaining in the seawater. .
In this embodiment, the sterilizing agent decomposing agent supply device 7 is provided in the sterilizing agent decomposing treatment line 11, and the sterilizing agent decomposing agent is added to the ballast water in which the sterilizing agent stored in the ballast tank 9 remains when the ballast water is discharged. The disinfectant is decomposed and discharged into the sea.
As shown in FIG. 3, the disinfectant-disassembling agent supply device 7 stores the disinfectant-disassembling agent storage tank 51 for storing the disinfectant-disassembling agent, and the disinfectant-disassembling agent in the disinfectant-disassembling agent storage tank 51 to the disinfectant-decomposing treatment line 13. A pipe 53 for supply, provided on the front end side of the pipe 53, and provided on the upstream side of the pump 3 of the bactericidal agent decomposition treatment line 11, injecting the bactericidal agent decomposing agent into the ballast water in which the bactericidal agent remains. And a supply pump 57 for supplying the disinfectant decomposition agent in the disinfectant storage tank 51 to the disinfectant decomposition processing line 11, a valve 59 for adjusting the supply amount of the disinfectant disassembly agent, and the like. .

Sodium sulfite, sodium bisulfite (sodium hydrogen sulfite), and sodium thiosulfate can be used as a disinfectant decomposer supplied to chlorine disinfectants such as sodium hypochlorite and chlorine.
Moreover, as a disinfectant decomposer supplied with respect to hydrogen peroxide, enzymes such as sodium sulfite, sodium bisulfite (sodium hydrogen sulfite), sodium thiosulfate, and catalase can be used. However, it is not limited only to these. An enzyme such as catalase works as a catalyst for the decomposition reaction and has a long reaction time.
The sterilizing agent decomposing agent supply device 7 is controlled by the sterilizing agent decomposing agent supply amount control device 61 shown in FIG. 3, and an appropriate amount of the sterilizing agent decomposing agent is supplied to a predetermined location.

5-1. Bactericide Degradant Supply Amount Control Device A bactericide decomposer supply amount control device 61 is discharged from the ballast tank 9 and a bactericide concentration meter 63 that measures the residual concentration of the bactericide in the seawater discharged from the ballast tank 9. A flow meter 65 that measures the flow rate of seawater, a bactericide concentration meter 66 that measures the residual concentration of bactericide in seawater supplied with a bactericide decomposer and decomposed, and a storage means 67 that stores various data. And a calculation means 69 for calculating the supply amount of the bactericidal agent decomposition agent, and a control means 71 for controlling the equipment based on the calculation result of the calculation means 69.

The disinfectant concentration meter 63 measures the disinfectant concentration in the seawater discharged from the ballast tank 9 and outputs it to the calculation means 69. The flow meter 65 measures the flow rate of seawater discharged from the ballast tank 9 to the sea and outputs it to the computing means 69. The disinfectant concentration meter 66 measures the residual disinfectant concentration in the seawater supplied with the disinfectant decomposer and decomposed, and outputs it to the calculation means 69.
As the disinfectant concentration meter 63, for example, when measuring residual chlorine derived from a chlorine disinfectant, a high concentration residual chlorine meter (for example, the measurement range is 0 to 30 mg / l) and a low concentration residual chlorine meter (for example, the measurement range is 0). By performing split detection of residual chlorine concentration using ˜3 mg / l), the detection accuracy of low concentration residual chlorine can be improved.
As the disinfectant concentration meter 66 for measuring the disinfectant residual concentration in the seawater in which the disinfectant is decomposed, a low concentration disinfectant concentration meter capable of detecting a low disinfectant concentration is preferable. It is preferable to use a low-concentration residual chlorine meter having a mechanism for measuring a reduction current corresponding to the free residual chlorine concentration. By using such a low-concentration residual chlorine meter that has high detection accuracy for low-concentration residual chlorine and can detect the absence of residual chlorine, the amount of chlorinated agent supplied is controlled to ensure that residual chlorine is eliminated. In addition, it can be confirmed that the residual chlorine is decomposed and the residual chlorine is gone.
The storage means 67 stores a relational expression (z = cx + d, c; predetermined coefficient (slope), d; intercept, which is predetermined as a relation between the disinfectant supply amount (z) and the disinfectant residual concentration (x). ) Is stored.
The above relational expression is based on the condition that affects the process until the supplied disinfectant decomposer is diffused and exhibits its effectiveness as an effective disinfectant disinfectant, and the disinfectant disinfectant supply amount (z) And the disinfectant residual concentration (x).

The calculation means 69 inputs the measurement result of the bactericide concentration meter 63 and obtains the average value of the bactericide residual concentration for a predetermined time. In addition, the measurement result of the flow meter 65 is input, and the average flow rate value for a predetermined time is obtained.
Further, the supply amount of the sterilizing agent decomposing agent to be supplied is calculated based on the sterilizing agent residual concentration average value and the data stored in the storage means 67. A specific method for calculating the disinfectant supply amount of the disinfectant will be described later.
Based on the calculation result of the calculation means 69, the control means 71 performs output control such as the rotation speed of the supply pump 57 and / or adjustment of the opening of the valve 59 for adjusting the supply amount.
Further, the calculation means 69 inputs the measurement result of the bactericide concentration meter 66, and when the bactericidal residual concentration is larger than the allowable value, the control means 71 adjusts the bactericidal agent supply amount to be supplied. Or the residual germicide concentration indicator may be output to a residual germicide concentration indicator (not shown).

The operation of the present embodiment configured as described above will be described.
Using the ballast water treatment device shown in Fig. 1, the bacteria and plankton are killed when the ballast water is loaded, and the disinfectant remaining in the seawater is decomposed and detoxified when the ballast water is discharged. A method for treating ballast water will be described.

<Operation when loading ballast water>
When the ballast water is loaded, the pump 3 is operated to take seawater from the seawater intake line 1 into the ship, the coarse filter 2 removes coarse material, and the filter 4 is sized according to the opening of the filter 4. Remove plankton.
A bactericidal agent is supplied to the seawater filtered by the filtering device 4 by the bactericide supplying device 5. The supply amount of the sterilizing agent is controlled by the sterilizing agent supply amount control device 31.

FIG. 4 is a flowchart showing the procedure of the bactericide supply amount control by the bactericide supply amount control device 31. Hereinafter, the procedure of the bactericide supply amount control will be described with reference to FIG.
When the operation of the disinfectant supply device 5 is started, first, the start-up operation is started for a time T1 by a timer (S1). Start operation, fungicides supplied from fungicides reservoir 21 is operated to perform until reaching the position established fungicide densitometer 33, bactericide supply amount at the time of starting operation and y _s.

The start-up operation is started and it is determined whether or not a predetermined time T1 has elapsed (S3). When the time T1 elapses, the timer is set at time T2 and normal operation is started (S5). When the normal operation is started, the bactericide concentration is measured by the bactericide concentration meter (S7). It is determined whether or not the time T2 has elapsed (S9). If it is determined that the time has elapsed, an average value x _ave of measured concentrations during the time T2 is obtained (S11). x _ave is obtained by dividing the sum of the measured concentrations by the number of measurements.
Then, the disinfectant concentration average value x _ave dead band range of disinfectant concentration predetermined _{(x s (1-c L} ) ≦ deadband range _{≦ x s (1 + c H} ), c L; dead zone lower limit width (e.g. (Greater than 0 and less than 0.20)

c _H : It is determined whether or not the dead zone upper limit width (for example, greater than 0 and less than 0.50) is deviated (S13).

And when it is judged that it has deviated, the disinfectant supply amount y (y) obtained by multiplying the disinfectant supply amount y by the dead zone control rate R _n to the disinfectant supply amount y _s corresponding to the target disinfectant concentration. = Y _s · R _n ) is obtained (S15). When the sterilizing agent supply amount y is obtained, the control means 41 inputs the obtained sterilizing agent supply amount y to obtain the obtained sterilizing agent supply amount. Alternatively, adjustment control of the opening degree of the supply amount adjustment valve 29 is performed. Then, it is determined whether or not the normal operation is finished (S17). If not finished, the process returns to the process of S5, the timer is reset, and the same process is repeated.
Note that the dead zone control rate R _n is expressed by the equation (1).
R _n = R _n−1 + (x _s −x _ave ) · a · w (1)
R _n-1 : dead zone control rate before 1 time (initial value of R R ₁ = 1)
a: Predetermined coefficient (greater than 0 and less than 1)
w: Dead band control width (greater than 0 and less than 1)

It should be noted that a more appropriate amount of bactericidal agent can be supplied by measuring the flow rate of the seawater to be processed, obtaining the flow rate average value for a predetermined time, and adjusting the bactericidal agent supply amount according to the flow rate average value. In this case, the calculation means may calculate the bactericide supply amount y based on the following formula.
y = y _s · R _n · (Q _ave / Q _s )
Q _ave ; Average flow rate Q _s ; Reference flow rate

Here, how to obtain the supply amount y of the bactericide will be described with specific numerical values.
x _s ; fungicide concentration target value: 10ppm
a; slope = 0.034
b; intercept = 0.097
Standard flow rate Q _s = 250m ³ / h
When the initial value y _s sterilizing agent supply amount is as follows.
y _s = (0.034 ・ 10 + 0.097) ・ 1 ・ 1 = 0.437L / min
The amount of bactericide supplied for normal operation control is x _ave = 11ppm, c _H = 0.05, c _L = 0.02, w = 0.1, Q _ave = 245 m ³ / h,
x _ave = 11 ≧ 10 · (1 + 0.05) = 10.5, which exceeds the dead zone region. Therefore, when obtaining the dead zone control rate R _2, is as follows.
Dead zone control rate R ₂ = 1 + (10-11) ・ 0.034 ・ 0.1 = 0.9966
Therefore, the disinfectant supply amount y is as follows.
Disinfectant supply amount y = 0.437 ・ 0.9966 ・ 245/250 = 0.4268L / min

Seawater to which a bactericidal agent is added is introduced into the venturi pipe 6. In the venturi tube 6, cavitation is generated to damage aquatic organisms, and diffusion of the bactericidal agent into seawater is promoted to increase the bactericidal effect.
Seawater treated by the venturi pipe 6 is sent to the ballast tank 9 via the sterilized treated water feed line 8 and stored. In the seawater stored in the ballast tank 9, it is preferable that the disinfectant supplied by the disinfectant supply device 5 remains at an appropriate concentration. Thereby, regrowth of bacteria and plankton can be controlled.

<Operation when discharging ballast water>
At the time of discharging the ballast water, the pump 3 is operated to introduce the ballast water from the ballast tank 9, and the bactericide decomposer is supplied from the bactericide decomposer supply device 7 provided in the bactericide decompose treatment line 11 and remains. Decomposes the disinfectant.
The supply amount of the bactericide decomposer is controlled by the bactericide decomposer supply amount controller 61, and an appropriate amount of bactericide decomposer is supplied to a predetermined location. Hereinafter, a method for controlling the supply amount of the disinfectant decomposition agent will be described.

The disinfectant concentration meter 63 measures the disinfectant residual concentration in the seawater discharged from the ballast tank 9 and outputs it to the calculation means 69.
The calculating means 69 inputs the measurement result of the bactericide concentration meter 63 and obtains the bactericide residual concentration average value x _ave for a predetermined time. When the average disinfectant residual concentration value x _ave is obtained, the disinfectant supply amount z of the disinfectant is obtained based on the relational expression (z = cx + d, c; predetermined coefficient (slope), d: intercept).
Based on the calculation result of the calculation means 69, the control means 71 performs output control such as the rotation speed of the supply pump 57 and / or adjustment of the opening of the valve 59 for adjusting the supply amount.
The ballast water that has been supplied with an appropriate amount of the bactericide decomposing agent and has been subjected to the disinfecting process of the bactericide is discharged into the sea via the bactericide decomposing water drain line 12.
Further, the calculation means 69 inputs the measurement result of the bactericide concentration meter 66, and when the bactericidal residual concentration is larger than the allowable value, the control means 71 adjusts the bactericidal agent supply amount to be supplied. Or the residual germicide concentration indicator may be output to the residual germicide concentration indicator. It can be confirmed that the residual germicide is not decomposed by displaying the residual germicide concentration on the residual germicide concentration indicator.

In addition, by measuring the flow rate of seawater at which the disinfectant is decomposed to obtain a flow average value for a predetermined time, and adjusting the disinfectant disintegrant supply amount according to the flow average value, a more appropriate amount of disinfectant can be decomposed. The agent can be supplied. In this case, the calculation means may calculate the disinfectant disinfectant supply amount z ′ based on the following formula.
z ′ = z · (Q _ave / Q _s )
Q _ave ; Average flow rate Q _s ; Reference flow rate

The above example is a case in which the biological killing process is performed when seawater is loaded into the ballast tank 9, but when the seawater is loaded into the ballast tank, the biological killing process is not performed and the ballast tank 9 is discharged. In some cases, the organism is killed.
In this case, untreated seawater is stored in the ballast tank 9 via an untreated seawater water supply line (not shown). When discharging this ballast water from the ballast tank 9, untreated ballast water in the ballast tank 9 is introduced to the filtration device 4 side via a ballast water supply line (not shown), and thereafter the same as above. Perform the process.
The ballast water that has been subjected to the biocidal treatment is introduced into the disinfectant disinfectant supply device 7 and supplied with the disinfectant decomposer, so that the remaining disinfectant is decomposed. The ballast water after the disinfecting process of the disinfectant is discharged into the sea.
Further, the biological killing process in the ballast water may be performed both when the seawater is loaded into the ballast tank 9 and when the seawater is discharged from the ballast tank 9. In that case, the biological killing process at the time of discharge of ballast water may be mild.

As described above, in the present embodiment, zooplankton and phytoplankton of 10 to 200 μm or more are removed by the filtration device 4 and the bacteria and plankton that have passed through the filtration device 4 by the venturi 6 are damaged. In addition, since bacteria and plankton were killed by killing them and supplying appropriate amounts of bactericides, treatment of ballast water that meets the ballast water standards set by IMO was realized reliably and inexpensively regardless of the water quality. it can.
Moreover, since the configuration of the apparatus is simple, it can be easily applied to existing ships, and microorganisms having resistance to disinfectant treatment and electrical treatment can be efficiently killed.

  In addition, although the example shown in FIG. 1 assumes that the detoxification treatment of ballast water is performed at the time of loading into a ballast tank and / or at the time of draining into the sea, either at the time of loading or at the time of draining The timing at which the treatment is performed can be determined depending on the amount of microorganisms inhabiting the water intake area and the operational conditions of the ship.

It is explanatory drawing of the ballast water treatment apparatus which concerns on one embodiment of this invention. It is explanatory drawing of the disinfectant supply apparatus in the ballast water treatment apparatus which concerns on one embodiment of this invention. It is explanatory drawing of the bactericidal agent decomposition agent supply apparatus in the ballast water treatment apparatus which concerns on one embodiment of this invention. It is a flowchart explaining operation | movement of the ballast water treatment apparatus in one embodiment of this invention.

Explanation of symbols

  2 Coarse filtration device, 3 pump, 4 filtration device, 5 disinfectant supply device, 6 venturi tube, 7 disinfectant disintegrator supply device, 9 ballast tank, 31 disinfectant supply amount control device, 61 disinfectant disinfectant supply amount control apparatus.

Claims (5)

A bactericidal agent supplying apparatus that supplies bactericidal agent into seawater, and aquatic organisms in seawater while receiving the supply of seawater supplied with bactericidal agent and generating cavitation in the seawater to diffuse the bactericidal agent in seawater Venturi tube that damages or kills the tube, and the concentration of the bactericide in the seawater discharged from the venturi tube is measured to determine the bactericidal concentration average value for a predetermined time, and the bactericidal concentration average value is determined in advance. When the dead zone range of the bactericide concentration is deviated, the bactericide supply amount supplied by the bactericide supply device is set to the bactericide supply amount according to the target bactericide concentration. ballast water treatment system, characterized in that it and a sterilizing agent supply amount control apparatus for adjusting to the supply amount obtained by multiplying the rate R _n.
R _n = R _n−1 + (x _s −x _ave ) · a · w (1)
R _n ; dead zone control rate R _n-1 ; dead zone control rate x _s ; previous bactericidal agent concentration target value x _ave ; bactericidal agent concentration average value a; predetermined coefficient w; dead zone control width The sterilizing agent supply amount control device measures a flow rate of seawater to be processed, obtains an average flow rate value for a predetermined time, and adjusts the sterilizing agent supply amount according to the flow rate average value. Ballast water treatment equipment. A bactericide decomposer supply device for supplying a bactericide decomposer to seawater to which a bactericide is supplied, and a concentration of the bactericide remaining in seawater are measured, and the bactericide decomposer is measured based on the measured residual bactericide concentration The ballast water treatment device according to claim 1, further comprising a bactericide decomposer supply amount control device that adjusts a bactericide decomposer supply amount of the supply device. The sterilizing agent decomposing agent supply amount control device measures the flow rate of seawater to be processed, obtains an average flow rate value for a predetermined time, and adjusts the sterilizing agent decomposing agent supply amount based on the average flow rate value. 3. The ballast water treatment apparatus according to 3. The ballast water treatment device according to any one of claims 1 to 4, further comprising a filtration device that filters seawater and captures aquatic organisms upstream of the disinfectant supply device.

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