DESCRIPTION
BALLAST WATER TREATMENT SYSTEM
Technical freld
The present inventron relates to ballast water treatment systems, and particularly
to a ballast water treatment system for removing aquatic organisms from the ballast water
of a ship
Background Art
Ships which transport ores, crude oil and the like are provided with a ballast
tank so that ballast water such as sea water and fresh water is stored in the ballast tank to
perfor m attitude control and stability marntenance of the hull. Since ballast water is
taken into the ballast tank when the ship is unloaded, and is discharged from the ballast
tank as the loading of cargoes progresses, it will be discharged in a legion different from
the locatron of water intake Therefore, aquatic organisms may be moved with the
ballast water and settle in a new environment, and in such a case, there anses a concern
that ecosystems are destroyed nd the business activitres such as fisher les are affected
Moreover, there is also a fear that pathogenic bactena which are moved with the ballast
water directly affect human health
Accordingly, in the Internatronal Conventron for the Management of Ships'
Ballast Water, "The Internatronal Conventron for the Control and Management of Ships'
Ballast Water & Sediments," was adopted in February, 2004, making it obligatory for ships to install a ballast water treatment apparatus The ballast water management
standards stipulated by the Internatronal Mantime organizatron (IMO) are as follows
+ Less than 10 viable organisms per cubic meter for organisms gieater than 01 equal to
50 micrometers in minimum dimension
Less than 10 viable organisms per milliliter for organisms less than 50 miciometcis in
minimum dimension and gieater than or equal to 10 miciometers in minimum dimension
* Toxicogenic Vibno choleiae (O-l and 0-139) is less than 1 colony for ming unit (cfu)
per 100 millilitcis
* Escherichia coll is less than 250 cfu per 100 milliliters

* Intestinal Enterococci is less than 100 cfu pe: 100 milliliters
In order to satisfy such slandards, various ballast vvalei treatment technologies
for punfying ballast water are proposed For example, conventronally sterilizatron
schemes have been the marn stream, in which a coarse filtering is pertormed by a fillet
(physical treatment) and thereafter disinfectants are added, in Patent Citatron 1, the
ballast water is sterilized rhiough the additron of chloune-based chemicals Morcovci
Patent Citatron 2 utilizes hydro peroxide to sterilize the ballast water and Patent Citatron
3 utilizes ozone to sterilize the ballast water
In lecent years, in place of stenlizatron schemes, a coagulatron/separatron
scheme is proposed as well For example, in Patent Citatron 4, chemicals and magnetic
powdei are added to the ballast water to entangle aquatic organisms, which arc the targct
of lemoval, thereby forming magnetic floes, and these magnetic floes are lecovered by
use of magnets and filters thereby separating/removing the target aquatic organisms
Patent Citatron 1 fapanese Patent Applicatron Lard-Open No 04-322788
Patent Citatron 2 Japanese Patent Applicatron Lard-Open No 05-910
Patent Citatron 3 Japanese Patent Applicatron Lard-Open No 2006-212494
Patent Citatron 4 Japanese Patent Applicatron Lard-Open No 2005-218887
Disclosure of Inventron
Technical problem
Ballast water may be taken in at any port around the world and its water quality
would significantly vary depending on the place of water intake for example in a
water area where water pollutron has become worse, the aquatic organisms existent in
water such as bacteria and planktons have increased due to eutrophicatron Morcovci,
even in the same water area, the volume of aquatic organisms may significantly vary
depending on the season, and a convectron flow etc may occui due to the temperature
difference between day and night resulting in a change in the volume or aquatic
organisms in a short period of time for this leason, it is very difficult to constantly
achieve the ballast water management standards established by the IMO, and an attempt
to fulfill the standards in an unreasonable manner may cause a new, adverse effect

for example, in Patent Citatrons 1 to 3, to secuicly achieve the standards, it is
necessary to inject an excess amount of disinfectant and as a lesult of the injection of an
excess amount of chemical liquids, there is a risk that the efficacy thereof remains
thereby adversely affecting the coating of the ballast tank and killing aquatic organisms
in that water area when the ballast water is discharged
Further, in order to securely achieve the standards in Patent Citatron 4 it is
necessary to add an excess amount of the chemicals for for ming magnetic floes, which
may cause a risk that due to the injectron of such excess amount of chemicals the
amount of magnetic floes to be lecovered needlessly increases
The present inventron has been made in view of the above described
circumstances, and has its object to provide a ballast water treatment system which can
constantly achieve the ballast water management standards established by the IMO
Technical Solutron
In order to achieve the above desenbed object, a first aspect of the present
inventron provides a ballast water treatment system including water ticatment apparatus
which lemoves substances to be removed from ballast water, and a ballast tank which
stores the ballast water treated by the water treatment apparatus installed on a ship, the
ballast water treatment system characterized by including a monitoring apparatus which
monitors a water quality of the ballast water, and a control apparatus which controls an
operatronal conditron of the water treatment apparatus based on a monitoung result of
the monitoung apparatus
Since the first aspect of the present inventron is configuied such that the water
quality of the ballast water is monitored and based on that lesult, the operatronal
conditrons of the water treatment apparatus are controlled, it is possible to treat the
ballast water enabling it to have a constant water quality even when the water quality of
t.ie ballast water significantly varies depending on water intake conditrons
Moreover, according to the first aspect, since water treatment is performed in
accordance with the water quality of the ballast water, it is possible to prevcnl an
excessive or insufficrent injectron of the chemical liquid which is used ior water
treatment for example, when a sterilizatron scheme is adopted for the water ticatment
apparatus, it is possible to prevent an excessive or insufficrent injectron of disinfectant

thcreby preventing the disinfectant from imposing a buiden on the coating of the ballast
tank and the environment
A second aspect of the present inventron is charactcnzed in that in the fust
aspect, the vvater treatment apparatus includes a coagulatron apparalus which coagulates
the substance to be removed by injecting a coagulant into and agitating the ballast walci
and a separatron/iemoval apparatus which separates and lemoves aggicgates which
occuis in the coagulatron apparatus
The second aspect is based on a coagulatron/separalion scheme which makes the
substances to be lemoved in the ballast water to coagulate thereby being
scparated/iemoved, and there is no need of injecting disinfectants as in a stenlizatron
scheme, thereby eliminating a buiden on the coating of the ballast tank and the
environment It is noted that a separatron/iemoval apparatus can utilize a giavity
settling, floatatron, magnetic separatron, filter separatron, etc
A thud aspect of the picsent inventron is charactcnzed in that in the second
aspect, the control apparatus controls the coagulatron apparatus based on the moniloring
lesult of the monitoring apparatus to adjust an injectron amount of the coagulant
According to the third aspect, since the injectron amount of the coagulant is
controlled in accordance vvith the water quality of the ballast water, it is possible to iniect
a j ust enough amount of the coagulant Therefore, it is possible to pi event the
coagulant irom being remarned due to an excess injectron of the coagulant, and to
minimize the buiden on the environment when the ballast water is discharged
A fouith aspect of the present inventron is charactenzed in that in the second 01
thud aspect, the separatron/iemoval apparatus is configuied as a combinatron of a
magnetic separatron and a filter separatron
According to the fouith aspect, since a magnetic separatron and a filter
separatron ate combined, it is possible to perfor m the separatron/iecovery of aggicgates
at a high speed and a high accuiacy It is noted that in the fouith aspect, it is picfciable
to admix magnetic powder into the ballast water befor e coagulatron Moreovci
magnetic separatron is preferably performed by using a magnet such as a permancnt
magnet, a supereonducting magnet, etc , and filter separatron is preleiably per lormed by
using a filter of 10 to 15 um made of metal 01 lesin

A fifth aspect of the present inventron is charactenzed in that in any of the fiist
to the fouith aspects, the monitoring apparatus monitors the ballast vvater by measuring at
least one of a tuibidity and a chiomaticity of the ballast vvater
According to the fifth aspect, since the monitoring is perfor mcd by measuring at
least one of a tuibidity and a chiomaticity, it is possible to indiiectly obtarn a lough
estimate of the concentratron of the aquatic orgamsms in the ballast walci Moreovci
many multipuipose apparatuses have been developed for a tuibidimetci and colornuclei
A sixth aspect of the present inventron is charactenzed in that in any of the Hi si
to the fouith aspects, the monitoring apparatus monitors the ballast watci by perfor ming
an image analysis of the ballast water
According to the sixth aspect, since the vvater quality of the ballast watci is
monitored by perfor ming an image analysis of the ballast watci, it is possible to dnccily
determine the concentratron of the aquatic orgamsms in the ballast water
A seventh aspect of the present inventron is charactenzed in thar in any or the
fitst to sixth aspects, the control apparatus controls atreatment volume that is lieated by
the water treatment apparatus per unit time
According to the seventh aspect, since the treatment volume per unit lime that is
a dwell time in the water treatment apparatus is controlled, it is possible 10 cfllcicnlly
lemovc the substances to be lemoved even when the substances lo be lemoved arc in a
latge amount in the ballast water For example, when a watci treatment apparatus based
on a sterilizatron scheme is used, it is possible to conliol a contact time pcnod with a
disinfectant by controlling the treatment volume per unit time Therefor e even when
there is an inflow of a high concentratron of orgamsms due to a ted tide, etc it is
possible to efficrently perfor m a sterilizatron treatment Moreovci, when a walei
treatment apparatus based on a coagulatron/separalion scheme is used, it is possible to
control the dwell time in the coagulatron apparatus by controlling the treatment amount
per unit time Therefor e, even when there is an inflow of a high concentialion of
orgamsms due to a led tide etc , it is possible to securely perfor m the coagulatron
treatment of aquatic organisms
An eighth aspect of the present inventron is charactenzed in that in any of the
Piist to the seventh aspects, the monitoring apparatus monitors the water quality of the

ballast water at an inlet patt of the water treatment apparatus, at an outlet parl of the
water treatment apparatus, and/or in the ballast tank
According the eighth aspect, it is possible to perfor m water treatment in
accordance with the variatron of water quality of the ballast water at the time of walci
intake by momtoring the water quality of the ballast water at an inlet part of the walci
treatment apparatus Moreover, it is possible to cope with a perfor mance change (a
degiadatron of performance, etc ) of the water treatment apparatus by momtoring the
water quality of the ballast water at an outlet part of the water treatment apparatus
Fuithci, it is possible to cope with the case in which the water quality is dcgiaded m the
lank by momtoring the water quality of the ballast watet in the tank
A ninth aspect of the present inventron is charactenzed in thar in any o( the Hi si
to ihe eighth aspects, the ballast water treatment system includes a line for ictuimng the
baflast water in the ballasr tank or the ballast water to be dischargcd trorn the ballast lank
to the outside to the water treatment apparatus, and the ballast water is letreated by Ihe
water treatment apparatus
According to the ninth aspect, it is possible to retreal the ballast walei and lor
example, when a large amount of the substances to be lemoved arc included in the ballast
water at the time of water intake, when the substances to be lemoved are not sufficrently
lemoved by the water treatment, or when the substances to be lemoved have giown in the
tank, the ballast water is letreated As a lesult of this, it is possible to dischargc ballast
water in a state in which it securely satisfres the standards It is noted that letreatmcnt
of the ballast water is prefeiably perfor med while the ship navigates and when the ballast
walci is discharged
Advantageous Effects
According to the present inventron, since the water quality of the ballast walci is
monitored and based on the result, the operatronal conditrons of the water treatment
apparatus are controlled, it is possible to treat the ballast water which significantly vanes
depending on water intake conditrons so that it has a desned water quality Thcicfor e
it is possible to securely satisfy the standards for the discharge of the ballast walci and
thereby pi eventing the destiuctron of ecosystem due to the dischargc of the ballast walci

Bnef Descriptron of Accompanying Drawings
[Figure 1] Figure 1 shows a first embodiment of the ballast water treatment system
relating to the present inventron.
[Figure 2] Figure 2 shows a ballast water treatment system which is different from that
of Figure 1
[Figure 3] Figure 3 shows the flow of water discharge m the ballast water treatment
system of Figure 1.
[Figure 4] Figure 4 shows a second embodiment of the ballast water treatment system
relating to the present inventron
[Figure 5] Figure 5 shows a ballast water treatment system which is different from that
of Figure 4
[Figure 6] Figure 6 shows the flow of water discharge in the ballast water treatment
system of Figure 4
[Figure 7] Figure 7 is a table to show the relatronship between the concentratrons of lo
aquatic organisms of ballast water and the concentratrons of chemical liquids
[Figure 8] Figure 8 is a table to show the relatronship between the turbidity of ballast
water and the adding amounts of coagulants
Explanatron of Reference
10 Ballast water treatment system, 12 Ship, 14 Water treatment apparatus,
16 . Ballast tank, 18 ..Monitoring apparatus, 20. Control apparatus, 22 Physical
removal apparatus, 24. .Sterilizing apparatus, 26 Raw-water piping, 28 Pump,
30. Valve, 32, .Treated water pipmg, 34 to 38 Sampling Pipe, 40. .Ballast water
treatment system, 42. Circulatron line, 44. Circulatron line, 46 Bypass line,
50 Ballast water treatment system, 52 Water treatment apparatus, 54 Chemicals
adding unit, 56 Coagulatron unit, 58 Separatron unit, 60 Magnetic powder adding
apparatus, 62.. Inorganic coagulant adding apparatus, 64 Polymeric coagulant
adding apparatus, 66 High-speed agitatron vessel, 68 Low-speed agitatron vessel,
70 Piping, 72 - Magnetic separatron apparatus, 74 Filter separatron apparatus,
80 Ballast water treatment system, 82 . Circulatron line
Best Mode for Carrying out the Inventron

Hereafter, prefeiable embodiments of the ballast watci treatment system i dating
to the present inventron will be desenbed according to the appended diawings
Figuie 1 schematically shows the configuiatron of a fust embodiment of the
ballast water treatment system relating to the present inventron The ballast watci
treatment system 10 shown in the figuie is installed in a ship 12 and is pnmanly made up
of a water treatment apparatus 14, a ballast tank 16, a monitoring apparalus 18 and a
control apparatus 20
The water treatment apparatus 14, which is an example of "stcnlizalion scheme"
is made up of a gioup of apparatuses including a physical lemoval apparatus 22 and a
stenlizing apparatus 24
The physical removal apparatus 22 physically removes largc aquatic organisms
and suspended solids, etc for which an apparatus utilizing, for example, a filtci a
cyclone, a cavitatron effect, and othcis are used singly or in combinatron A uiw-watci
piping 26 is connected to the physical lemoval apparatus 22 and a pump 28 and a valve
30 are auanged in the law-water piping 26 With the pump 28 being dnvcn sea watci
or fresh water is withdiawn into the taw-water piping 26 and is fed to the physical
lemoval apparatus 22 The pump 28 and the valve 30 are connected to the control
apparatus 20, and the revolutronal speed of the pump 28 and the opening of the valve 30
are controllcd by the control apparatus 20 It is noted that depending on the design of the stenlizing apparatus 24 in the latter stage, an embodiment in which the physical
lemoval apparatus 22 is not installed may be possible Fuither, instead of using the
pump 28, a difference in water level may be utilized to feed sea water or fresh watci
The physical removal apparatus 22 is connected to a ballast tank 16 via a ticatcd
watci piping 32, and the stenlizing apparatus 24 is provided at some pornt in the ticatcd
water piping 32 The stenlizing apparatus 24 kills small aquatic organisms for which
an apparatus utilizing, for example, sodium hypochlonte, ozone, chlonnc dioxide
peracctic acid, hydiogen peroxide, ultia-violet light and others are used singly or in
combinatron A specific example of the stenlizing apparatus 24 is made up of a
chemicals storage vessel for storing a disinfectant (not shown) and an injectron apparatus
(not shown) for injecting the disinfectant into the treated watci piping IVloreover, an
embodiment which includes a generatron apparatus (not shown) for genciarmg a
disinfectant is also possible

The treated water from which aquatic organisms are lemovcd by the physical
lemoval apparatus 22 and the sterilizing apparatus 24 is fed to and stored in the ballast
tank 16 It is noted that as water discharge means for discharging the ballast watci m
the ballast tank 16 to the outside, an embodiment which discharges watci by use of the
law-water piping 26 and the pump 28, and an embodiment which discharges watci by
connecting a new water-discharging piping (not shown) to the ballast lank 16 may be
possible
Sampling pipes 34, 36, and 38 are lespectively connected to the law-warci
piping 26 (that is, an inlet part of the water treatment apparatus 14) the ticalcd watci
piping 32 (that is, an outlet part of the water treatment apparatus 14), and the ballast lank
16, and each of the sampling pipes 34, 36, and 38 is connected to the monitoring
apparatus 18 The monitoring apparatus 18 automatically samples the ballast water
withdiawn via the sampling pipes 34, 36, and 38 to investigate the walei quality ihcicol
The method of investigating water quality is not specifically limited and (or example
there is a method of directly measuring the concentiatron of aquatic organisms by
acquning image data of the ballast water by photogiaphing and perfor ming an image
analysis of the image data Fuither, water quality may also be dctcimincd indiiectly busing a tuibidity meter for measuring a tuibidity in water and a calonmclci for mcasuring
a chiomaticity in water
The monitoring apparatus 18 is connected to the control apparatus 20 and the
data of monitoring lesult is transmitted to the control apparatus 20 The control
apparatus 20 is connected to the pump 28, the valve 30, the physical lemoval apparatus
22, and the sterilizing apparatus 24 so that based on the monitoring lesult, the operatronal
conditrons of the physical lemoval apparatus 22 and the steulizing apparatus 24 the
i evolutronal speed of the pump 28, and the opening of the valve 30 are ad|ustcd This
allows for the control of the operatronal conditrons of the watci ticatment apparatus 14
such as the treatment volume of aquatic organisms and the ticatment flow late per unit
time, etc
Next, the operatron of the ballast water treatment system 10 which is configuicd
as desenbed above will be described
In the present embodiment, the ballast waters of the law-water piping 26 the
treated water piping 32, and the ballast tank 16 are sampled That is, the watci qualitres

of the ballast vvater at the time of water intake, the ballast water immediately aflci the
Ucalment by the water treatment apparatus 14, and the ballast water stored in the ballast
tank 16 are monitored Then, the control apparatus 20 controls the operatronal
conditrons of the water treatment apparatus 14 in accordance with the water quality thus
perlorming ballast water treatment
for example, when the water quality of the ballast water of the taw-watci piping
26 (that is, the ballast water at the time of water intake) degiades lesulting in an increasc
in ihe concentiatron of aquatic orgamsms, the treatment capacity of the water ttcatment
apparatus 14 is increased such as by increasing the amount of disinfectant to be inputted
to ihe stenlizing apparatus 24 and decreasing the treatment flow tale by the pump 28
ancl/or the valve 30 On the contiary, when the water quality or the ballast water at the
tunc of water intake improves lesulting in a decrease in the concentiatron of aquatic
orgamsms, the treatment capacity of the water treatment apparatus 14 is decicascd such
as by decreasing the amount of disinfectant to be inputted to the stenlizing apparatus 24
and increasing the treatment flow rate by the pump 28 and/or the valve 30 This will
make it possible to cope with vauatrons in the water quality of the law water of ballast
water thereby stabilizing the water quality of the ballast water aftci treatment
Morcover, by controlhng the operatronal conditrons of the water treatment apparatus 14
in accordance with the watet quality of the law water of ballast water, it is made possible
to prevent the disinfectant being excessively injected from the stenlizing apparatus 24
thus pi eventing the redundant disinfectant from adversely affecting the local ecosystem
when the ballast water is discharged
Similarly, it is possible to cope with a case in which the water quality of the
ballast water of the treated water piping 32 (that is, the ballast water immediately aftci
treatment) vanes That is, when the concentiatron of aquatic orgamsms mcicascs the
treatment capacity of the water treatment apparatus 14 is increased such as by increasing
the amount of the disinfectants to be inputted to the stenlizing apparatus 24 and
decreasing the treatment flow late by the pump 28 and the valve 30 On the contiary,
when the concentiatron of aquatic orgamsms decreases, the treatment capacity of the
water treatment apparatus 14 is decreased such as by decreasing the amount of the
disinfectants to be inputted to the stenlizing apparatus 24 and increasing the treatment
How late by the pump 28 and the valve 30 This will make it possible to per lorm a

ieedback control of the water treatment apparatus 14 thereby stabilizing the watci quality
of (he ballast water after treatment It is noted that comparing the water quality of the
ballast water of the law-water piping 26 with the water quality of the ballast water of the
ticated water piping 32 will make it possible to more quickly and accmalcly cope with
vanalions in the water quality of the taw water of the ballast watci thereby fuilhci
stabilizing the water quality of the ballast water after treatment
Jn the present embodiment, the water quality of the ballast water in the ballast
tank 16 is also monitored thereby allowing for the supervision of the water quality of the
ballast water in the ballast tank It is noted that when the watci quality in the ballast
tank degiades, it can be coped with by a method in which the ballast watci in the ballast
tank is cuciliated into the water treatment apparatus 14 and is tetreated, a method m
which when the ballast watci in the ballast tank is dischargcd, it is fed to the watci
treatment apparatus 14 and is retreated to be discharged, or fuither a method in which the
stenlizing apparatus 24 is connected to the ballast tank so that the inside of the ballast
tank is sterilized, or the like
Thus, according to the present embodiment, since the water quality ot the ballast
wf.ter is monitored and based on the lesult thereof, the operatronal conditrons of the
watci treatment apparatus 14 are controlled, it is possible to always marntarn a constant
wflci quality of the ballast water even when the water quality or the ballast water
significantly diffeis depending on water intake conditrons
Fuither, according to the present embodiment, since the watci treatment is
per for med in accordance with the water quality of the ballast water it is possible to
inject a proper amount of chemical liquid in accordance with the concentiatron of aquatic
organisms here, the relatronship between the concentiatron of aquatic organisms and
each disinfectant is shown in the table of Figuie 7 In the present embodiment, it is
possible to inject an appropnate amount of a chemical liquid based on such relatronship
thereby allowing for the preventron of excessive or insufficrent injectron of the chemical
liquid Therefore, it is possible to prevent the lesidual chemical liquid horn imposing a
buden on the coating of the ballast tank 16 and the ecosystem in the arca of watci
discharge
It is noted that in the table of Figuie 7, the standard for aquatic organism A is
"less than 10 viable organisms per cubic meter for organisms gieatci than or equal to 50

u,ni in minimum dimension," and the standard for aquatic organism B is "less than 10
viable organisms per millihter for organisms less than 50 urn and gicatci than or equal to
10 urn in minimum dimension "
It is noted that although in the above desenbed embodiment the watci quality of
the ballast water is momtored at three places (the law-water piping 26 the ticatcd water
piping 32, and the ballast tank 16), the locatron and the numbci of pornts to be momtored
are not limited to these and, for example, the water quality of the ballast walci may be
sampled at one or two of the above described places
Figuie 2 is a schematic diagiam of a system in which a functron oJ iclicalmg the
ballast water in the ballast tank 16 is provided in the ballast water treatment system of Tiguic 1 The ballast water treatment system 40 shown in the figuie is configuied such
that a cnculatron line 42 is connected to the ballast tank 16, and the front end or the
cuculatron line 42 is connected to the law-water piping 26 The cnculatron line 42 is
provided with a pump and a valve which are not shown, and the pump and the valve arc
controlled by a control apparatus 20 It is noted that, the front end of the cnculatron
line 42 may be connected to the piping of the upstream side (the left side in Figuie 2) of
the pump 28 so that the pump 28 and the valve 30 are used for both water intake and
cnculatron
In the ballast water treatment system 40 configuied as desenbed above the
valei quality of the ballast water in the ballast tank 16 is momtored and based on the
momtoring lesult, the operatronal conditrons of the water treatment apparatus 14 arc
controlled for example when the water quality of the ballast watci in the ballast lank
16 dcgiadcs the ballast watci in the ballast tank 16 is cuculatcd to the walci treatment
apparatus 14 thiough the cnculatron line 42 and letreatment of the ballast watci is umicd
out Then, in accordance the water quality of the ballast watci in the ballast lank 16 the
operatronal conditrons of the water treatment apparatus 14 are controlled to cany out
.eticatment of the ballast water until the concentiatron of aquatic organisms becomes less
than or equal to a permissible value This makes it possible to improve the water
quality of the ballast water in the ballast tank 16 and keep it less than or equal to the
permissible value

Thus, in the present embodiment, it is possible to cnculate and putily the ballast
water in the ballast tank 1 5 and, for example, the piuiiicalion ofthe ballast watci can be
per lormed while the ship navigates
It is noted that in the above descubed embodiment, although the ballast watci in
the ballast tank 16 is leturned to a former stage ofthe physical lemoval apparatus 22 it
may be returned to the former stage ofthe sterilizatron pornt by the stcnlizing apparatus
24 as shown by the circulatron line 44 indicated in Figure 2 In this case, a lclicatmcnt
including only a sterilizatron treatment is possible
Fuither, although in the above descubed embodiment the watci quality of the
ballast water in the ballast tank 16 is monitored and in accordance with the lcsult thcreol
leticatment ofthe ballast water is controlled, configuiatron may be such that the watci
quality ofthe ballast water in the ballast tank 16 is compared with the water quality of the ballast water immediately after the treatment and in accordancc with the companson
lcsult, the operatronal conditrons at the time of leticatment are controllcd for example
configuiatron may be such that when the water quality of the ballast watci immediately
after the treatment becomes equivalent to the water quality ofthe ballast watci in the
ballast tank 16, letreatment ofthe ballast water is stopped
Figuie 3 is a schematic view to show the flow in per for ming the water dischargc
ir the ballast water treatment system 10 of Figure 1 It is noted that although the (low of water discharge in the figuie shows an example of perfonmng watci dischargc by use
ofthe watci treatment apparatus 14, the pump 28, and the valve 30 of Figuie 1, the
method of water discharge is not limited to this method, and water dischargc may be
per (ormed by providing a water treatment apparatus, a pump, and a valve which arc
diffcrent from those for the time of water intake
The ballast water treatment system 10 shown in Figuie 3 is configiucd such that
with the valve 30 being opened and the pump 28 being driven, the ballast watci in the
ballast tank 16 is discharged to the outside thiough the water treatment apparatus 14
The control apparatus 20 controls the water treatment apparatus 14 in accordancc with
the monitoring lcsult ofthe water quality ofthe ballast water in the ballast lank 16 for example, when the water quality (the concentiatron of aquatic organisms) ofthe ballast
water in the ballast tank 16 exceeds a permissible value, the water treatment apparatus 14
is dnven to stArt letreatment ofthe ballast water, and the operatronal conditrons (a

ticalmcnt volume such as the injectron amount of disinfectant and a ticatment flow i ate
per unit time) of the vvater treatment apparatus 14 are controllcd in accordancc with the
walci quality of the ballast water This will improves the water quality o( the ballast
water to be discharged and the ballast water is controlled to be less than 01 equal to a
permissible value and is discharged
Thus, according ?o the present embodiment, since configuiatron is made such
that the water treatment apparatus 14 is disposed on the discharge line o( the ballast
wcter, it is possible to perfor m tetreatment of ballast water at the time o( discharge
Tterefor e, even when the water quality of the ballast water in the ballast tank 16
degiades duung navigatron, it is possible to satisfy the discharge standard lor ballast
water by letreating the ballast water at the time of discharge
It is noted that although, in the above descubed embodiment, configuiatron is
imdc such that the ballast water at the time of water discharge flows to the physical
icmoval apparatus 22 as well, the configuiatron may be such that a bypass line 46 of the
physical icmoval apparatus 22 is provided so that water is dischargcd without passing
thiough the physical lemoval apparatus 22 as shown in Figuie 3
Figuie 4 schematically shows the configuiatron of the ballast water ticalmcnt
system of a second embodiment It is noted that the membeis which have the same
functrons as those of the ballast water treatment system fO shown in Figuie 1 are given
the same leference numbeis thereby omitting the desenptron thcreof
As shown in Figuie 4, compared with the ballast water treatment system 10 of
the fust embodiment shown in Figuie 1, the ballast water treatment system 50 of the
second embodiment is different in that a water treatment apparatus 52 based on a
coagulatron/separatron scheme is used The water treatment apparatus 52 based on a
coagulatron/separatron scheme, which coagulates the substances to be tcmoved (aquatic
organisms) in the ballast water to be separated and lemoved is made up of a chemicals
adding unit 54 a coagulatron unit 56, and a separatron unit 58 as shown in Figuie 4
The chemicals adding unit 54, which adds chemicals neccssary (or coagulating
the substances to be lemoved (aquatic organisms) in the ballast water, includes a
magnetic powder adding apparatus 60, an inorganic coagulant adding apparatus 62 and a
Dolymenc coagulant adding apparatus 64 in the present embodiment The magnetic
oowder adding apparatus 60 is configured to add magnetic powder to the ballast water to

be fed to a high-speed agitatron vessel 66 of the coagulatron unit 56, and as the magnetic
ponder, for example, trnion tetraoxide (Fe3C>4) is preferably used The inorganic
coagulant adding apparatus 62 is configuied to add inorganic coagulants to the ballast
water which is fed to the high-speed agitatron vessel 66 of the coagulatron unit 56 and as
the inorganic coagulant, polyaluminum chloude, non chlondc feme sulfate etc arc
prefeiably used The polymeric coagulant adding apparatus 64 is configuied to add a
pclymeuc coagulant to the ballast water to be fed to the low-speed agitatron vessel 68
from the high-speed agitatron vessel 66 of the coagulatron unit 56, and as the polymcnc
coagulant, anionic and nonionic coagulants, etc may be prefeiably used It is noted that
the kind of chemicals to be added is not limited to the above dcsenbcd embodiment and
for example, an embodiment which does not include the magnetic powder adding
apparatus 60 is possible as well, when the magnetic separatron apparatus 72 is not used
in the separatron unit 58 in the latter stage
The coagulatron unit 56 includes a high-speed agitatron vessel 66 to which
ballast water is fed from the ravv-water piping 26, and a low-speed agitatron vessel 68
which is connected to the high-speed agitatron vessel 66 thiough a piping 70 The high-
speed agitatron vessel 66 is configured to lapidly agitate the ballast water, magnetic
powder, and a coagulant by rotating an agitator blade which is not shown at a high speed
The agitating blade in the high-speed agitatron vessel 66 has prefeiably a lotatronal
pcnpheral speed of about 1 to 2 m/sec at its tip end part, and by using the high-speed
agitatron vessel 66 like this, minute magnetic floes having a size of scvcial tens o(
miciometers are for med, in which magnetic powder, solid floating particlcs in the ballast
\vatci bactena, planktons, etc are taken in The ballast water contarning magnetic floes
is fed to the low-speed agitatron vessel 68 via the piping 70
The low-speed agitatron vessel 68 is configuied to slowly agitate the ballast
water contarning magnetic floes and a polymenc coagulant by lotatmg the agitator blade
which is not shown at a low speed The agitator blade of the low-speed agitatron vessel
68 is controrled to have a lower rotatronal pcnpheral speed than that of the agitator blade
of the high-speed agitatron vessel 66 By using such low-speed agitatron vessel 68 it is
possible to giow magnetic floes, and large magnetic floes having a size of scvcial
hundicd miciometers TO several milhmeters are for med The ballast water contarning
giown magnetic floes is fed to the separatron unit 58 It is noted that although in the

present embodiment, the coagulatron unit 56 is made up of the high-speed agitatron
vessel 66 and the low-speed agitatron vessel 68, the configutatron of the coagulatron unit
56 is not limited to this configuratron, and various embodiments, ior example, one in
which several kinds of agitatron vessels of different agitating methods ate providcd arc
possible
The separatron unit 58 includes a magnetic separatron apparatus 72 and a fillci
separalion apparatus 74 The magnetic separatron apparatus 72 aclsorbs and scparatcs
magnetic flocks in the ballast water by magnetic for ce, and not less than about 99% of the magnetic flocks in the law water is separated and removed by the magnetic
separatron apparatus 72 The treated water which has been treatcd by the magnetic
separatron apparatus 72 is fed to the filter separatron apparatus 74 The filtci separatron
apparatus 74 utilizes a rotating dium filter (not shown) having a filtci of a porc size of 10
to 50 urn, and the ballast water is supplied to the innei side of the totaling dium filtci so
that the ballast water is fed from the innei side to the outer side thereby being fillcicd
ard thus small fish and shnmps, which cannot be lemoved by coagulatron are icmovcd
This makes it possible to lemovc contaminants such as dusts, solid floating par tides,
bactena, planktons, etc m the ballast water thereby punfying the ballast water The
punficd ballast water is fed to the ballast tank 16 through treated water piping 32 to be
slorcd therein It is noted that the configuiatron of the separatron unit 58 is not limited
tc the above desenbed embodiment, and vanous embodiments are possible such as an
embodiment in which no filter separatron apparatus 74 is provided, and an embodiment
in which in place of the magnetic separatron apparatus 72, separatron apparatuscs such as
those based on settling separatron and floatatron separatron, etc arc utilized
The ballast water treatment system 50 of the above desenbed second
embodiment is configured such that as with the fust embodiment, sampling pipes 34 36
and 38 are lespectively connected to the law-water piping 26, the treatcd water piping 32
and the ballast tank 16, and each of the sampling pipes 34, 36 and 38 is connected to the
monitoring apparatus 18 The monitoring apparatus 18 automatically samples the
ballast water withdiawn via the sampling pipes 34, 36, and 38 to investigate the water
ouality thereof The method of investigating water quality is not specifically limited,
and for example, there is a method of dnectly measuring the conccnlialion of aquatic
organisms by acquuing image data of the ballast water by photogiaphing and perfor mmg

an image analysis of the image data Fuither, water quality may also be deter mined
indiicctly by using a turbidity meter for measuring a turbidity in vvater and a calonmctci
for measuring a chromaticity in water
The monitoung apparatus 18 is connected to the control apparalus 20 and the
data or monitoung lesult is tiansmitted to the control apparatus 20 The control
apparatus 20 is connected to the pump 28, the valve 30, the chemicals adding unit 54
ard the coagulatron unit 56, and based on the monitoung lesult, the operatronal
conditrons of the chemicals adding unit 54 and the coagulatron unit 56, the I evolutronal
speed of the pump 28, and the opening of the valve 30 are adjusted This allows for (he
control of the operatronal conditrons of the water treatment apparatus 52 such as the
trealmcnt volume of aquatic organisms and the treatment flow tatc per unit time, etc
According to the second embodiment configuied as dcsciibcd above since the
vvater quality of the ballast water is monitored and, based on the lesult thereoJ the
operatronal conditrons of the water treatment apparatus 52 are controlled, it is possible lo
a]ways marntarn a constant water quality of the ballast water even when the water quality
of the ballast water significantly diffeis depending on water intake conditrons
for example, when the water quality of the ballast water o1 the law-walci piping
26 degiades lesulting in an increase in the concentiatron of aquatic organisms the
ucalment capacity of the water treatment apparatus 52 is mcicased such as by mcicasmg
the amount of chemicals to be inputted in the chemicals adding unit 54, enhancing the
agitating effect in the coagulatron unit 56 to increase the amount of coagulatron and
■ leueasing the treatment flow late by the pump 28 and/or the valve 30 On the contiary
\vhcn the water quality of the ballast water at the time or water intake nnprovcs lesulting
in a decreasc in the concentiatron of aquatic organisms, the treatment capacity of the
water treatment apparatus 52 is decreased such as by decreasing the amount ofchumcals
to be inputted to the chemicals adding unit 54, decreasing the agitating effect in the
coagulatron unit 56 to decrease the amount of coagulatron, and increasing the treatment
flow late by the pump 28 and/or the valve 30 This will make it possible to cope with
vanatrons in the water quality of the raw water of ballast water, thcicby stabilizing the
water quality of the ballast water after treatment Moreovci, by controlling the
operatronal conditrons of the water treatment apparatus 52 in accor dance with the water
quality of the law water of ballast water, it is made possible to prevent the chemicals of

the chemicals adding unit 54 being excessively added thus pi eventing ad vase effects on
the local ecosystem when the ballast water is discharged
Sunilarly, it is possible to cope with a case in which the walei quality of the
ballast water of the treated water piping 32 (that is, the ballast water immediately afta
treatment) vanes That is, when the concentratron of aquatic organisms mcicases the
licatment capacity of the water treatment apparatus 52 is inaeased in the same fashion as
clcsenbed above, and when the concentiatron of aquatic organisms decreascs the
treatment capacity of the water treatment apparatus 52 is decicased This will make it
possible to perfor m a feedback control of the water treatment apparatus 52 thcicby
stabilizing the water quality of the ballast water after treatment It is noted that
ccmparing the water quality of the ballast water of the iaw-\vater piping 26 with the
water quality of the ballast water of the treated water piping 32 will make it possible lo
Morc quickly and accurately cope with variatrons in the water quality of the taw water of
the ballast water thereby fuither stabilizing the water quality of the ballast water afta
treatment
In the present embodiment, the water quality of the ballast water in the ballast
tank 16 is also momtored thereby allowing for the supervision of the water quality of the
ballast wala in the ballast tank 16 It is noted that when the water quality in the ballast
tank 16 degiades, as desenbed later, it can be coped with by a method in which the
ballast water in the ballast tank 16 is circulated into the water treatment apparatus 52 and
is letreated, or a method in which when the ballast water in the ballast tank 16 is
discharged, it is fed to the water treatment apparatus 52 and is letreated to be discharged,
or the like
As desenbed above, in the second embodiment, since the operatronal conditrons
of the water treatment apparatus 52 are controlled in accordance with the water quality of
the ballast water, it is possible to add an appropriate amount of coagulant in accordance
with the concentiatron of aquatic organisms Here, the relatronship between the
tuibidity of the ballast water and the adding amount of coagulant is shown in the table of
Figuic 8 According to the present embodiment, it is possible to add an appropnatc
amount of coagulant based on such relatronship
It is noted that the table of Figuie 8 shows a case in which polyalummum
chlonde is used as an example of the inorganic coagulant

Fuither, in the second embodiment, since the vvater Ueatmcnt apparatus 52 based
on a coagulatron/separatron scheme is used it is possible to pi event aclvcisc effects on
the ecosystem as in a case in which disinfectants are used Fuither, since when the
water treatment apparatus 52 based on a coagulatron/separatron scheme is used, mud (chit
dead bodies of organisms, etc ) will not be accumulated in the ballast tank 16 it is
possible to prevent an increase of aquatic organisms in mud Therefor c, it is possible to
inhibit the water quality of the ballast water in the ballast tank 16 from being degiadcd
It is noted that although in the above desenbed embodiment, the water quality of
the ballast water is monitored at three places (the law-water piping 26 treatcd water
piping 32, and ballast tank 16), the locatron and the numbei of pornts to be monitored arc
not limited to these and, for example, the water quality of the ballast water may be
sampled at one or two of the above described places
Figuie 5 is a schematic view of a system in which a functron of icticaling the
ballast water in the ballast tank 16 is provided in the ballast water treatment system of
Figuie 4 The ballast water treatment system 80 shown in the figuie is configuied such
thar a circulatron line 82 is connected to the ballast tank 16, and the lionl end ofthc
ci dilatron line 82 is connected to the taw-water piping 26 The en dilatron I me 82 is
provided with a pump and a valve which are not shown and the pump and the valve arc
controlled by a control apparatus 20 It is noted that, the front end or the uiculatron
line 82 may be connected to the upstream side (the left side in Figuie 5) o( the pump 28
so that the pump 28 and the valve 30 are used for both the times of water intake and
cnculatron
In the ballast water treatment system 80 configuied as desenbed above the
water quality of the ballast water in the ballast tank 16 is monitored and based on the
monitoring lesult, the operatronal conditrons of the water treatment apparatus 52 arc
controlled for example, when the water quality of the ballast water in the ballast tank
16 degiades, the ballast water in the ballast tank 16 is cnculatcd to the water treatment
apparatus 52 thiough the cnculatron line 82 and ictreatment of the ballast water is slArtcd
Then, in accordance with the water quality of the ballast water in the ballast tank 16 the
operatronal conditrons of the water treatment apparatus 52 arc controlled to can v out
letreatment of the ballast water until the water quality becomes less than or equal to a

permissible value As a lesult of this, the water quality of the ballast watci in the ballast
tank 16 is improved and controlled to be less than or equal to a peunissible value
Thus, in the present embodiment, it is possible to cnculate and punfy the ballast
water in the ballast tank 16 and, for example, the punficatron of the ballast watci can be
pcrfor med while the ship navigates
Fuither, although in the above descubed embodiment, the water quality o( the
ba.last water in the ballast tank 16 is monitored and in accordance with the icsult thcicof
letreatment of the ballast water is controlled, configuiatron may be such that the watci
quality of the ballast water in the ballast tank 16 is comparcd with the watci quality of
the ballast water immediately after the treatment and in accordancc with the companson
iesult, the operatronal conditrons at the time of letreatment arc controllcd for example,
configuiatron may be such that when the water quality of the ballast walei immediately
aflci the treatment becomes equivalent to the water quality of the ballast watci in the
ballast tank 16, letreatment of the ballast water is stopped
Figuie 6 is a schematic view to show the flow in perfor ming watci dischargc in
the ballast water treatment system 50 of Figuie 4 It is noted that although the How of
water discharge in the figuie shows an example of perfor ming water dischargc by use of the water treatment apparatus 52, the pump 28, and the valve 30 of Figuie 4, the watci
ducharge method is not limited to this method, and water dischargc may be perlormcd
b) providing a water treatment apparatus, a pump, and a valve different liom those lor
the time of watci intake
The ballast water treatment system 50 shown in Figuie 6 is configuicd such that
with the valve 30 being opened and the pump 28 being dnven, the ballast watci in the
ballast tank 16 is discharged to the outside through the water treatment apparatus 52
T'le control apparatus 20 controls the water treatment apparatus 52 in accordancc with
the monitoring iesult of the water quality of the ballast water in the ballast tank 16 for example, when the water quality (the concentratron of aquatic organisms) of the ballast
watci in the ballast tank 16 exceeds a permissible value, it stArts letreatment of the
ballast water by driving the water treatment apparatus 52 and controls the operatronal
conditrons (a treatment volume such as the injectron amount of coagulant and a
treatment flow late per unit time of ballast water, etc ) of the water treatment apparatus
52 in accordancc with the watci quality of the ballast watci Since this will improvc the

water quality of the ballast water to be discharged, it is possible to dischargc ballast
watci which is controlled to be less than 01 equal to the permissible value
Thus, since according to the present embodiment, configuiatron is made such
that the water treatment apparatus 52 is incorporated on the discharge line of ballast
watci it is possible to perfor m letreatment of ballast water at the time of dischargc
thereby improving the water quality Therefor e, even when the water quality of the
ballast water in the ballast tank 16 degiades during navigatron, it is possible to satisfy the
discharge standard for ballast water by retreating the ballast water at the time of
discharge

We clarm
1 A ballast water treatment system comprising
a water treatment apparatus which treats ballast water and is installed on a
ship,
a monitoring apparatus which monitors a water quality of the ballast water at
an inlet part or an outlet part of the water treatment apparatus, and
a control apparatus which monitors the water quality of the ballast water at a
time of intaking the ballast water, wherein
the control apparatus controls an opening of a valve which is disposed on a
piping which connects a pump for intaking and discharging the ballast water, the
valve, the water treatment apparatus and a ballast tank in this order, based on a
monitoring result to adjust a treatment flow rate per unit time in the water
treatment apparatus, and
the control apparatus monitors the water quality of the ballast water at a
time of discharging the ballast water, and
when the water quality based on the monitoring result satisfres a permissible
value, the control apparatus controls so as to discharge the ballast water, and
when the water quality based on the monitoring result does not satisfy the
permissible value, the control apparatus controls so as to retreat the ballast water
and then discharge the ballast water
2 The ballast water treatment system as clarmed in clarm 1, further compnsing
a circulatron line whose one end is connected to the ballast tank and another
end is connected to an upstream side of the pump, wherein
the ballast water is fed to the water treatment apparatus via the circulatron
line
3 The ballast water treatment system as clarmed in clarm 2, wherein

the monitoring apparatus monitors the water quality of the ballast water in
the ballast tank, and
based on a monitoring result of monitoring of the water quality of the ballast
water in the ballast tank, the control apparatus controls to circulate the ballast
water in the ballast tank to the water treatment apparatus so as to make the ballast
water retreated, or to feed the ballast water in the ballast tank to the water
treatment apparatus at the time of discharging the ballast water so as to make the
ballast water retreated before discharging the ballast water
4 The ballast water treatment system as clarmed in any one of clarms 1 to 3,
wherein the water treatment apparatus comprises a physical removal apparatus or a
sterilizing apparatus
5 The ballast water treatment system as clarmed in clarm 4, wherein the
sterilizing apparatus utilizes at least any one of sodium hypochlorite, ozone, chlorine
dioxide, peracetic acid, hydrogen peroxide and ultra-violet light
6 The ballast water treatment system as clarmed in any one of clarms 1 to 3,
wherein
the water treatment apparatus comprises
a coagulation apparatus which coagulates substance to be removed by
injecting a coagulant into and agitating the ballast water, and
a separatron/removal apparatus which separates and removes aggregates
which occurs in the coagulatron apparatus
7 The ballast water treatment system as clarmed in clarm 6, wherein
the separatron/removal apparatus is configured as a combinatron of a
magnetic separatron and a filter separatron
8 The ballast water treatment system as clarmed in any one of clarms 1 to 7,
wherein

the monitoring apparatus monitors the ballast water by measuring at least
one of a turbidity and a chromaticity of the ballast water
9 The ballast water treatment system as clarmed in any one of clarms 1 to 7,
wherein
the monitoring apparatus monitors the ballast water by performing an image
analysis of the ballast water
10 The ballast water treatment system as clarmed in any one of clarms 1 to 9,
further comprising
a sampling pipe which is connected to the monitoring apparatus, wherein
the monitoring apparatus automatically samples the ballast water via the
sampling pipe and monitors the water quality of the ballast water
11 The ballast water treatment system as clarmed in clarm 5, wherein
the control apparatus controls an injectron amount of disinfectant based on
the monitoring result of the water quality of the ballast water at the inlet of the water
treatment apparatus or the water quality of the ballast water at the outlet of the
water treatment apparatus
12 The ballast water treatment system as clarmed in clarm 6, wherein
the control apparatus controls an injectron amount of coagulant based on the
monitoring result of the water quality of the ballast water at the inlet of the water
treatment apparatus or the water quality of the ballast water at the outlet of the
water treatment apparatus

ABSTRACT

Since the ballast water treatment system relating to an aspect of the present
inventron is configured such that the water quality of the ballast water is monitored and
based on that lesult, the operatronal conditrons of the water treatment apparatus are
controlled, it is possible to treat the ballast water enabling it to have a constant water
quality even when the water quality of the ballast water significantly vanes depending on
water intake conditrons. Moreover, since water treatment is performed in accordance
with the water quality of the ballast water, it is possible to prevent an excessive or
insufficrent injectron of the chemical liquid which is used for water treatment.
For example, when a sterilizatron scheme is adopted for the water treatment apparatus it is
possible to prevent an excessive or insufficrent injectron of disinfectant, thereby
preventing the disinfectant from imposing a burden on the coating of the ballast tank and
the environment.