Note: Descriptions are shown in the official language in which they were submitted.
~701~
SPECIFICATION
The present invention relates to a method and apparatus
for keeping aquatic animals alive over a long period of
time. More particularly, the present invention relates to
a method and apparatus Eor keeping aquatic animals alive in
an environmental water over a long period of time witllout
feeding them. The term "environmental water" used herein
refers to water in which the live aquatic animals are
placed to keep them alive. The environmental water may be
supplied from -the sea, rivers or city water supply.
In order to keep aquatic animals which have been
caught, for example, fish, shell fish, crustaceans and
mollusks alive, for as long as possible, the aquatic animals
are usually placed in a fish preserve provided by partitioning
a portion of the sea or a river and allowed to move freely.
However, recently, some portions of the seas and rivers,
particularly, close to big cities, have been heavily polluted.
Therefore, the live aquatic animals placed in the fish pre-
serves located in such polluted seas or rivers often die
within a short period of time.
In another conventional method, the live aquatic
animals are placed in a container through which nonpolluted
water flows is recycled, and are allowed to move freely in
the container. This method is effective for keeping the
aquatic animals alive for a long period of time. However,
this conventional method requires a container with a large
volume as well as a large amount of the fresh water, so
that the aquatic animals can move freely in the environmental
water in the container. Further, this conventional method
requires a continuous supply of fresh water into the container
- 2 -
~L~7~
and a continuous discharge of water from the container.
The continuous supply and dlscharge of the environmental
water results in the cost of -this method being very high.
Generally speaking, a live aquatic animal has energy
metabolism. This energy metabolism involves standard
energy metabolism and action energy metabolism. Generally,
the value of the rnetabolic action energy is abou-t 3 to 10
times that of the metabolic s-tandard energy. Therefore, in
case where the live aquatic animal can move freely, it is
necessary to feed the aquatic animals. Further, it is
obvious that the conventional metllods can not be utilized
for the purpose of transporting of live aquatic animals
over a long period of time.
An object of the present invention is to provide a
method and apparatus for keeping aquatic animals alive over
a long period of time, in a relatively small container, and
at a relatively low cost.
Another object of the present invention is to pro-
vide a method and apparatus for keeping aquatic animals
alive over a long period of time, without the continuous
supply of fresh environmental water.
A further object of the present invention is to pro-
vide a method and apparatus for keeping aquatic animals
alive, said method and apparatus being utilizable for
transporting the aquatic animals over a long period of
time.
The above-mentioned objects can be attained by -the
method and apparatus of the present invention. The method
of the present invention comprises the operations of:
(A) placing aquatic animals in environmental water
~7~)189
in a density larger than 200 kg/m3;
(B) controlling the temperature of the environmental
water so that it is maintained at a level as low as the
aquatic animals are able to exist;
(C) controlling ammonia compounds in the environ-
mental water so that their cotal concentration does not
exceed 20 ppm;
. (D) controlling water-soluble organic compounds in
the environmental water so that their total concentration
does not exceed 150 ppm;
(E) controlling carbonic acid radieal in the environ-
mental water so that it does not exceed a concentration of
1000 ppm, and;
(F) regulating molecular oxygen dissolved in the
environmental water so that its concentration is maintained
at 3 ppm or more.
The above-mentioned method can be effected by utilizing
the apparatus of the present invention which comprises:
(A) a water tank for containing aquatic animals and
environmental water, said tank having an inside volume
large enough to receive said aquatic animals in a density
larger than 200 kg per m3 of said environmental water;
(B) a control path for containing a portion of said
environmental water, said control path being located
outside said water tank;
(C) a withdraw pipe line connecced at one end
thereof to the bottom portion of said water tank and connected
at the other end thereof to the inlet portion of said
control path;
(D) a return pipe line connected at one end thereof
-- 4
to said water tank and connected at the other end thereof
to an outlet portion of said control path;
(E) means for controlling the temperature of said
environmental water in said control path so that it is
maintained at a level as low as it is possible for said
aquatic animals to exis-t, said temperature control means
being disposed in said control path;
(F) means for bringing said environmental water in
said control pa-th into contact with air;
(G) means for eliminating ammonia compounds from
said environmental water, said ammonia compounds eliminating
means being located in said control path;
(H) means for eliminating water-soluble organic
compounds from said environmental water, said water-soluble
organic compounds eliminating means being located in said
control path, and;
(I) a pump for recycling said environmental water
through said water tank said withdraw pipe line, said
control path and said return pipe line.
The features and advantages of the present invention
will be exemplified and more fully explained in the des-
cription presented below with reference to the accompanying
drawings, in which;
Fig. 1 is an explanatory diagram of an embodimen-t
of the apparatus of the present invention;
Fig. 2 is an explanatory diagram of another em-
bodiment of the apparatus of the present invention, and;
Fig. 3 is an explanatory diagram of a further
embodiment of the apparatus of the present invention.
It is well known that when live aqua-tic animals are
-- 5 --
~7C1 189
kept in environmental water, the environmental water is
contaminated with excretions of the aquatic animals due to
their metabolism. As stated hereinbefore, the metabolism
involves standard metabolism and action metabolism, and the
value of the metabolic action energy is abou-t 8 to 10 times
that of the metabolic standard energy. Also, it is known
-that the value of the metabolic standard energy of the
aquatic animal at a certain temperature can be reduced to
one half of the above-mentioned value by lowering the
temperature of the aquatic animals to a temperature 10C
below the above-mentioned certain temperature. Further, it
is known that the value of the metabolic action energy of
the aquatic animal can be reduced by restricting the movement
of the aquatic animals. I~owever, it has been long believed
that in order to keep the aquatic animals alive, it is
necessary to maintain the aquatic animals at an optimum
temperature at which the aquatic animals can exist while
allowing the aquatic animals to move freely. It has also
been believed that when the live aquatic animals are contained
in the environmental water in a relatively large density of
from 80 to 200 kg/m3, the aquatic animal can be kept alive
for only about 50 hours or less.
Contrary to the above the inventors of the present
invention discovered that as long as each of -the concentrations
of ammonia compounds, water-soluble organic compounds, car-
bonic acid radical and molecular oxygen in the environmental
water is controlled so as to be maintained at a predetermined
value, the aquatic animals can be kept alive over a long
period of time even if the aquatic animals are restricted
in their movement in the environmental water at a temperature
~7~
as low as it is possible for the aquatic animals to exist.
The present invention is based on this discovery. That is,
in the rnethod of the present invention, the aquatic animals
are contained in the environmental water in an extremely
high density of more t~.an 200 kg/m2, preferably, greater
than 200 kg/m2 but not exceeding 700 kg/m3, more preferably,
from 250 to 600 kg/m3, and the temperature of the environmental
water is maintained as low as it is possible for the aquatic
animals to exist. The large density of the aquatic animals
results in restriction in movement of the aquatic animals
in the environmental water, and this restriction causes a
low consumption of the metaboric action energy of the
aquatic animals.
For example, when adult prawns each havlng an average
weight of 30 g are received in the environmental water at a
density of 300 kg/m , the prawns substantially can not
optionally move. The low temperature of the environmental
water results in a low consumption of the metabolic standard
energy of the aquatic animals. Therefore, under these
circumstances, most of the metabolic energy of the aquatic
animals is consumed for the purpose of maintaining their
life. This results in the life of the aquatic animals
being extended. In the method of the present invention,
the extended life of the aquatic animal is about 10 to 20
times that of the aquatic animals maintained in the conventional
method.
In the method of the present invention, the temperature
of the environmental water is adjusted, for example, in the
case of adult red sea-bream, to a range from 7 to 12C, in
the case of adult carp, to from 3 to 20C, in case of adult
~076~
eels, to from 10 to 15C, in case of adult prawns, to from
10 to 15C, in case of abalones, to from 5 to 14C and .in
case of ask shells, to from 3 to 12C.
While the aquatic animals are kept being alive in
the environmental water, the aquatic animals consume molecular
oxygen dissolved in the environmental water and excrete
carbon dioxide,ammonia compounds and water-soluble organic
compoullds, such as ammonia; primary, secondary and tertiary
amine compounds, for example, urea, uric acid, creatine,
creatinine and trimethyl amine; arnino acids; higher fatty
acids, lipids and proteins. The aquatic animals cannot be
kept alive in environmental water containing certain amounts
of the above-mentioned excxeted compounds and a very small
amount of molecular oxygen.
The supply of the molecular oxygen into the environ-
mental water and the removal of the carbon dioxide from the
environmental water can be effected by bringing the environ-
mental water into contact with air so as to allow the
molecular oxygen in the air to dissolve in-to the environmental
water and, also, so as to allow the carbon dioxide in the
environmental water to be released from the environmental
water into the air. The contact of the environmental water
with the air may be effected by blowing and bubbling air
into the environmental water or by spraying the environmental
water into theatmospheric air. These operations are simple
and economical.
However, the ammonia compounds are very soluble in
water and at a pH of 7 to 9, at which the aquatic animals
can exist, most of the ammonia compounds are in the form of
onium compounds such as ammonium compounds which are non-volatile.
-- 8
7~1L89
Accordingly, the ammonia compounds can no-t be removed from
the environmental water by the above mentioned contact of
the environmental water with the air. Also, the water-soluble
organic compounds, such as, urea, uric acid, crea-tine,
creatinine, amino acids, higher fatty acids and trimethylamine
which are non-volatile, can not be removed by the simple
contact of the environmental water with the air.
In the method of the present invention, the aquatic
animals are placed in the environmental water in an extremely
high density of more than 200 kg/m3 and the temperature of
the environmental water is maintained at a level as low as
it is possible for the aquatic animals to exist. The high
density and the low temperature cause a low consumption of
the molecular oxygen and low excretions of carbon dioxide,
ammonia compounds ànd water-soluble organic compounds by
the aquatic animals in the environmental water. Also, in
the method of the present invention, the concentrations of
the ammonia compounds, the water-soluble organic compounds
and the carbonic acid radical in the environmental water
are controlled so as to be maintained at levels not exceeding
20 ppm, 150 ppm and 1000 ppm, respectively. Also, the
concentration of th~ molecular oxygen dissolved in the
environmental water is controlled so as -to be maintained at
3 ppm or more.
The above-mentioned controls of the concentrations
of the ammonia compounds, water-soluble organic compound,
carbonic acid radical and molecular oxygen dissolved in the
environmental water may be carried out by continuously
flowing fresh water containing less than 20 ppm of the
ammonia compounds, less than 150 ppm of the water-soluble
g
89
organic compounds~ less than 1000 ppm of the carbonic acid
radical and more than 3 ppm of molecular oxygen, and having
a predetermined low temperature, throughout the environment
oE the aquatic animals. That is, the removal of the excretions
of the aquatic animals can be effected by continuously
replacing the environmental water with fresh water at a
proper flow rate, so as to always maintain the environmental
water in a lean and uniform condition. The Elow rate of
the fresh water may be determined based on the type of the
aquatic animals. Usually, the flow rate is in a range of
from 20 to 1000 liters/hour kg, preferable, 20 to 400
liters/hour kg, of aquatic animals.
In the case where the environmental water is kept in
the environment of the aquatic animals for a long period of
time withou-t supplying more fresh environmental water, or
in the case where only a portion of the used environmental
water is replaced by fresh water, it is necessary to recycle
the environmental water through the environment of the
aquatic animals and to the outside of that environment. In
this case, while the environmental water is outside of the
environment of the aquatic animals, the ammonia compounds,
water-soluble organic compounds and carbonic acid radical
are eliminated from the environmental water, molecular
oxygen is dissolved into the environmental water, and the
environmental water is adjusted to a predetermined temperature.
The total concentration of the ammonia compounds may
be determined by the indophenol method. The total concentration
of the water-soluble organic compounds may be determined in
accordance with the JIS K-0102, KMnO4 method. The concentration
of carbonic acid radical may be determined by the Conway
- 10 -
~7~
microdiffusion analysis method. The concentration of
molecular oxygen may be determined by using a DISSOLVED
OXYGEN TESTER, Model 51, made by Yellow Spring Co.
The elimination of the ammonia compounds from the
environmental water may be effected by bringing the en-
vironmelltal water into contact wi-th a mass of adsorbing
material which is capable of allowing the environmen-tal
water to flow through the mass. The adsorbing material may
be selected from organic polymeric ion-exchange resins; in
organic ion-exchange materials, for example, natural zeolite,
synthetic zeolite, aluminium alumino-silica-te, magnesium
alumino-silicate, silica, alumina, acid clay and activated
clay; zirconium type ion-exchange materials, for example,
zirconium phosphate, zirconium tungstate and æirconium
molybdate; activated carbon, and; mixtures of two or more
of the above-mentioned materials. These materials are very
effective for removal of the ammonia compound even by using
-them in a relatively small amount.
The above-mentioned adsorbing materials are particularly
effective for eliminating the ammonia compound from sea
water. When the environmental water is supplied from a
river or city water system, the adsorbing material may be
an organic polymeric ion-exchange resin, for example, a
strong acidic cation~exchange resin, such as, sulfonic acid
and salt type ca-tion-exchange resins, and a weak acidic
cation-exchange resin, such as, carboxylic acid and salt
type cation-exchange resins. The ion-exchange resin may be
used in a mixture with the aforementioned adsorbing materials.
In this case, the adsorbing material containing the cation-
-exchange resin can remove a small amount of certain kinds
1~7(;~
of amine compounds from the environmental water. The
ammonia compounds may be eliminated by uslng a reverse
osmosis device or an ion-exchange membrane device.
The elimination oE the water-soluble organic compounds
from the environmental water may be effected by bringing
the environmental water into contact with a mass of adsorbing
material which is capable of allowing the environmental
water to flow through the mass. The adsorbing material may
be selected from natural and synthetic zeolites, activated
carbon, silica, silica-alumina, bone black, acid clay,
activated clay, aluminium alumino-silicate, magnesium
alumino-silicate, and mixtures of two or more of the above-
-mentioned materials.
The water-soluble organic materials may be eliminated
from the environmental water by bringing the environmental
water into contact with aluminium hydroxide, so as to allow
the organic compounds to coagulate and precipitate together
with the aluminium hydroxide and then separating the pre-
cipitation from the environmental water.
The elimination of the carbonic acid radical (carbon
dioxide dissolved in the environmental water) may be carried
out by bringing the environmental water into contact with
atmospheric air by any of the conventional methods, for
example, a method in which the air is blown and bubbled
into the environmental water or a method in which -the
environmental water is sprayed or ejected into the atmospheric
air. By these methods, the carbonic acid radical is released
in the form of carbon dioxide from the environmental water
into the atmospheric air.
The molecular oxygen can be supplied in-to the
- 12 -
1~7()9L~3~
environmental water by bringing the environmental water
into contact with air. This contact can be realized by
blowing and bubbling air into the environmental water or by
spraying or ejecting the environmental water into the
S atmospheric air. During the time in which the air contacts
the environmental water, the molecular oxygen in the air
can be dissolved into the environmental water. In place o~
air, oxygen gas may be used.
The temperature of -the environmental water can be
adjusted by using any of the conventional methods in which
the environmental water is heated or cooled to a desired
temperature.
In the method of the present invention, the ammonia
compounds and the water-soluble organic compounds may be
eliminated, in addition to the afore-mentioned adsorbing
methods, by bringing the environmental water into contact
with an oxidizing agent. In this method, after the oxidation,
the remaining oxidizing agent must be converted into a
substance which is non-toxic to the aquatic animals. The
oxidizing agent may be selected from hypohalogenic acid
compounds, for example, hypochloric compounds or hypobromic
acid compounds, and hypoionic acid compounds; hydrogen
peroxide; ozone; and mixtures of two or more of the above-
-mentioned substances.
~hen hydrogen peroxide or ozone are u-tilized as an
oxidizing agent, a portion of the ammonia compounds is
converted into nitric acid and/or nitrous acid. This
conversion causes a decrease of pH of the oxidized en-
vironmental water. Accordingly, it is necessary to control
the environmental water so tha-t its pH is maintained between
~ ~318~3
6.5 to 9.0~
The most prsferable hypohalogenic acid compound is
sodium hypochlorite. This compound has a high oxidizing
efficiency. ~The resultant compounds from the oxidation of
the ammonia compounds and the organic compounds, and the
decomposition product of the sodium hypochlorite are non-
-toxic to the aquatic animals. Even if the sodium hypochlorite
is used for the environmental water of fresh-water aquatic
animals, there is no toxicity problem with regard to the
aquatic animals.
The conversion of the remaining oxidizing agent
after the oxidation may be effected by mixing a reducing
agent, for example, sodium thiosulfate or sodium sulfite,
into the environmental water containing the remaining
oxidizing agent. ~owever, this method has the following
disadvantages. Not only does the feeding operation of the
reducing agent into the environmental water require a
complicated process and apparatus, but it is difficult to
control -the amount of the reducing agent to be added to the
environmental water. Even if the amount of the reducing
agent could be exactly controlled, the conversion product
from the reducing agent is often toxic or in~urious to the
aquatic animals. Accordingly, the above-mentioned mixing
of the reducing agent is not always preferable for the
aquatic animals.
The most preferable method for converting the remaining
oxidizing agent into a substance which is non-toxic to the
aquatic animals is a catalytical decomposition of the
remaining oxidizing agent. The catalyst for decomposing
the remaining oxidizing agent may be selected from natural
- 14 -
"` 31~)'7~8~a
zeolite, synthetic zeolite, aluminium alumino-silicate,
magnesium alumino-silicate, silica, alumina, activated
clay, acid clay, activated carbon made from coconut shell,
activated carbon made from coal, and mixtures of two or
more of the above-mentioned materials. In view of the
- decomposition capacity per unit volume, the most pr~ferable
catalyst is the above-mentioned activated carbons, which
are effective for all types of oxidizing agents.
In an experiment conducted by the inventors of the
present invention, when sea water containing 10 ppm of
sodium hypochlorite was brought into contac-t with 400 ml of
natural zeolite of 3 mm in size per particle obtained from
Miyagi-Ken, Japan, at a f~ow rate of 6 liters/hr., the
treated sea water contained 3.1 ppm of the sodium hypochlorite.
That is, 69% by weight of the sodium hypochlorite was
decomposed. In comparison with the natural zeolite, when
activated carbon of 3 mm in size per particle was used, the
treated sea water contained 0.6 ppm of the sodium hypochlorite.
That is, 99.4~ by weight of the sodium hypochlorite was
decomposed.
The operational conditions to be set forth for
eliminating the ammonia compounds include the kind, structure,
shape and amount of the adsorbing material, the kind and
amount (supply rate) of the oxidizing agent, structure of
the control device in which the elimination is carried out,
and the flow rate of the environmental water to be treated
(duration time of the environmental water in the control
device). These conditions should be set forth so as to
obtain an optimum result. For example, when sea water
containing 2 ppm of arnmonia compounds flows at a flow rate
- 15 -
~7~39
of 6 liters/hr throuyh 280 g (400 ml) of natural zeolite of
3 mm in size per particle, and the initial concentration of
sodium hypochlorite added to the sea water is 27.8 ppm, the
treated sea water contains 0.21 ppm of the ammonia compounds.
When 135 g ~300 ml) of synthetic aluminium alumino-silicate
of 3 mm in size per particle, having a ratio by weight of
A12O3:SiO3 of 23:77, are used in place of the natural
zeolite, the treated sea water contains 0.28 ppm of the
ammoni.a compounds.
The operational conditions for eliminating the
water-soluble organic compounds should be set forth in the
same manner as stated for the operational conditions for
eliminating the ammonia compounds. For example, when sea
water containing 10 ppm of the water-soluble organic compounds
flows at a flow rate of 6 liters/hr through 160 g (400 ml)
of activated carbon and the initial concentration of the
sodium hypochlorite is 10 ppm, the resultant sea water
contains 1.8 ppm of the organic compounds.
The treating conditions for the environmental water
may be set forth based on the kind and amount of the aquatic
animals, the amount of the environmental water to be treated,
the excretions of the ammonia compounds and organic compounds,
and the resistance of the aquatic animals to the ammonia
and organic compounds. For example, in the case where
1.3 kg of live prawns, each having an average weight of
about 30 g, are placed in 3.6 liters of the environmental
sea water, and the environmental water is recycled at a
flow rate of 6 liters/hr, the ammonia compounds and the
water-soluble organic compounds excreted by the prawns can
be almost completely eliminated by using 280 g of natural
- 16
7a~8~
zeolite of 3 mm in size per particle for elimlnating the
ammonia compounds, and 160 g of activated carbon of 3 mm in
size per particle for eliminating the water-soluble organi.c
compounds, and adjusting the concentration of the sodium
hypochlorite in the environmental water to 27.8 ppm. That
is, the environmental water can be maintained a-t a concentration
of the ammonia compound of 1 ppm or less and at a concen-tration
of the water-soluble organic compounds of 10 ppm or less.
In the above-mentioned case, the concentration of the
residual sodium hypochlorite in the treated environmental
water is 4.6 ppm. The residual amount of the sodium hypochlorite
can be almost completely decomposed by bringing the treated
environmental water into contact with 240 g of activated
carbon of 3 mm in size per particle.
In the method of the present invention, the operation
for eliminating the ammonia compounds and the operation for
eliminating the water-soluble organic compounds may be
carried out in an optional order.
The method of the present invention can be applied
to any kind of the aquatic animals, for example, adults and
fries of (A) aquatic animals of Class Osteichthys; for
example, sea breams such as Chrysophrys major, Oplegnathus
fas~iatus and Mylio macrocephalus, pink salmons such as
Oncobynchus nerka and Salmogairdnerii irideus, sweet fish,
namely, Plecoglossus altivelis; loach, namely, Misgurnus
anguillicaudatus, crucian, namely, Carassius carassius,
carp, namely, Cyprinus carpio; eel, namely, Anguilla japonica;
conger eel, namely, Conger japonicus; horse mackerels such
as Trachurus japonicus and Caranx delicatissmus; sea bass,
namely Lateolabrax japonicus, puffer such as Fugurubripes
~07~L !39
rubripes; and flat flshes such as Paralichthys olivaceus,
Limanda herzensteini and Limanda yokohamae; (B) aguatic
animals of Arthropoda Class Crustacea; for example, prawns
such as Penaeus japonicus, Penaecus semisulcatus ar,d r~etapeneus
joyneri, shrimps such as Sergestes lucens, Pandalus kessleri
and Pandalus borealis; lobsters such as Panulirus japonicus
and crabs such as Erimacrus isenbeckii, Parlithodes camtchatica,
Chionoecetes pitio, Portunus tribuberculatus and Macrocheria
kaempferic; (C) aquatic animals of Mollusca Class Lamellibranchia,
for example, oysters, such as, Osteria gigas, scallops such
as Pecten yessoensis, ask shells such as Anadara broughtonii;
cockle, namely, Fulvia mutica; and hard clams such as
Meretrix meretrix lusoria; (D) aquatic animals of Mollusca
Class Gostropoda, for example, abalones such as Halictis
gigantea, Haliotis sieboldi, Haliotis kamtschatkana, Haliotis
japonica and Haliotis discus; and (E) aquatic animals of
Echinodermata; for example, sea-urchins such as Echinoidea
and sea cucumbers such as Holoihuroidea; (F) onomats such
as Amyda sinensis; (G~ edible frogs such as Pana catesbiana,
and; (H) edible snails such as Hilix ponatia.
By utilizing the method of the present invention,
the aquatic animals can be kept alive for a long period of
several days to several weeks or more. Before the present
invention, it was never possible to keep aquatic animals
alive for the above-mentioned long period of time. Accordingly,
it is obvious that the method of the present invention is
very valuable and practical.
The method of the present invention can be effected
by using the apparatus of the present invention.
Referring to Fig. 1 of the drawings, a water tank 1
- 18 -
gl 8~
for containing aquatic animals and environmental water has
an inside volume large enough to contain aquatic animals at
a density of more than 200 kg per m3 of the environmental
water. A control path 2 for containing a portion of the
environmental water withdrawn from the water tank 1 is
located outside the water tank 1. The bottom portion of
-the water tank 1 is connected to an inlet portion of the
control path 2 through a withdraw pipe line 3 having a
pump 5 for withdrawing a portion of the environmental water
from the water tank 1 and for introducing the withdrawn
portion of water it into the control path 2. The withdraw
pipe line 3 may be provided with a filter 4 for removing
solid materials from the environmental water and a valve 6
for opening and closing the pipe line 3. The outlet portion
of the control path is connected to the water tank 1 through
a return pipe line 7 through which the withdrawn portion of
the environmental water can be returned back into the water
tank 1. Accordingly, the environmental water can be recycled
through the water tank 1~ the withdraw pipe line 3, the
pump 5, the control path 2 and the return pipe line 7. The
outlet end of the retu.rn pipe line 7 may be opened at any
portion of the water tank 1 as long as the returned water
can be uniformly distributed in the water tank 1 and, then,
evenly withdrawn at the inlet end of -the withdraw pipe line
3~ If it is necessary, the return pipe line 7 can be
provided with a pump and a valve which are not shown in
Fig. 1. The control path 2 is connected at its inlet
portion to a supply source of fresh environmental water
(not shown in Fig. 2) through a supply pipe 8 and a pump 9.
The control path 2 contains therein a means 10 for controlling
- 19 -
the temperature of the environmental water in the control
path 2 at the lowest possible temperature at which the
aquatic animals are able to exist, a means 11 for bringing
the environmental water in the control path into contact
with air, a means 12 for eliminating ammonia compounds, and
a means 13 for eliminating water-soluble organic compounds
from the environmental water.
The temperature control means 10 may be composed of
a heat-exchanger through which a heating medium or a cooling
medium can flow as shown in Fig. 1. The temperature control
means 10 is preferably located in the inlet portion of the
control path 2.
The means 11 for bringing the environmental water
into contact with air is preferably composed of an air
pipe 14 connected to an air blowing pump 15 as shown in
Fig. 1. An end portion of the air pipe 14 inserted into
the control path 2 has a number of holes through which air
bubbl es are blown into the environmental water flowing in
the control path 12.
The means 12 for eliminating the ammonia compounds
may be a mass of adsorbing material which allows the environ-
mental water to flow therethrough. The means 13 for eliminating
the water-soluble organic compounds may also be a mass of
adsorbing material which allows the environmental water to
flow therethrough.
The water tank 1 may have a discharge pipe 16 for
discharging the environmental water from the water tank 1.
The discharge pipe 16 may be provided with a valve 17 for
opening and closing the discharge pipe 16, and may be
located at an upper par-t of the water t.ank 1 for discharging
- 20 -
~07~1 39
the portion of the environmental water which has overflowed
from the water tank 1, as shown in Fig. 1.
In the apparatus shown in Fig. 2, the discharge
pipe 16 has a branch pipe line 21 connected to a heat-exchanger
22 located within the inlet portion of the con-trol path 2.
- When the valve 17 is closed, a portion of the environmental
wa-ter overflowed from the water tank 1 is introduced into
the heat-exchanger 22 for causing heat-exchange to occur
between the overflowed environmental water and the fresh
environmental water supplied into the inlet portion of the
control path 2 through the supply pipe 8 and pump 9. Then,
the portion of the overflowed environmental water is dis-
charged through a pipe 23 to the outside of the apparatus.
The branch pipe line 21 may be provided with a pump 24 and
a valve 25. In the control path 2 shown in Fig. 2, the
ammonia compound eliminating means 12 and the water-soluble
organic compounds eliminating means 13 are arranged in
parallel to each other. A stirrer 26 is also disposed in
the control path 2 for agitating the environmental water in
the control path 2 and for causing the environmental water
to pass through the eliminating means 12 and 13. The
return pipe line 7 has a pump 27 for forcibly sending the
environmental water from the control path 2 into the water
tank 1.
In the apparatus shown in Fig. 3, a tank 31 for
storing a solution of an oxidizing agent is connected to an
outlet end portion of the withdraw pipe line 3 through a
pipe 32, a pump 35 and a valve 33 for causing an oxidizing
agent solution to be admixed into the withdrawn portion of
the environmental water. In the apparatus shown in FigO 3,
07~8g
the environmental water containing the oxidizing agent
flows through the control path 2. In the control path 2,
-the environmental water comes in-to contact with the ammonia
compounds eliminating means 12, the water-soluble organic
compounds eliminating means 13 and finally, the means 34
- for decomposing the remaining oxidizing agent. In the
decomposing means 34, the remaining oxidizing agent is
converted into a substance which is non-toxic to the aquatic
animals. Thereafter, the environmental water is brought
into contact with air by the air contacting means 11, and
the temperature of the environmental water is adjusted to a
desired temperature by the means 10.
Hereinafter, the invention of the present application
is illustrated in detail by the following examples.
Example 1 and Comparison Examples 1 through 6
In each of the Example 1 and Comparison Examples 1
through 6, 1665 prawns (Penaeus japonicus) each having a
average weight of about 30g were placed in a water tank
having an inside volume of 125 liters (50cm x 50cm x SOcm).
Next, the water tank containing the prawns was filled with
fresh sea water. The density of the prawns in the environ-
mental sea water was about 400 kg/m .
In Example 1, fresh sea water was introduced into a
control tank and regulated to a temperature of about 10C,
and air was blown and bubbled into the fresh sea water. In
order to keep the prawns alive in the water tank, the
environmental water in the water tank was continuously
replaced by fresh sea water introduced from the control
tank at a rate of 1.25 m3/hr. The environmental water
discharged from the water tank was introduced into a
- 22 -
~07~)~8~
heat-exchanger located within the control tank for cooling
the fresh sea water in the control tank, and then the
environmental water was discharged therefrom.
Ten days after the start of the experiment, the
concentrations of ammonia compounds, water-soluble organic
- compounds, carbonic acid radical, and molecular oxygen in
-the environmental water discharged from the water tank were
determined.
In Comparison Example 1, the same procedures as
those used in Example 1 were carried out except that 400
prawns were placed in the environmental water of the water
tank at a density of 96 kg/m3.
In Comparison Example 2, the same procedures as
those used in Example 1 were effected except that the
temperature of the environmental water was adjusted to 25C.
In Comparison Example 3, the same procedures as
those used in Example 1 were carried out except that the
total concentration of the ammonia compounds in the environmental
water was regulated to 21 ppm by adding ammonium chloride
to the fresh sea water in the control tank.
In Comparison Example ~, the same procedures as
those used in Example 1 were carried out except that the
total concentration of the water-soluble organic compounds
in the environmental water was regulated to 160 ppm by
adding the excretion of prawns to the fresh sea water in
the control tank.
In Comparison Example 5, the same operations as
those used in Example 1 were conduc-ted except -that the
concentration of the carbonic acid radical in the environmental
water was controlled to 1200 ppm by adding sodium carbonate
- 23 -
~L~7~
to the fresh sea water in the control tank~
In Comparison Example 6, the same procedures as
those used in Example 1 were performed except that the
concen-tration of molecular oxygen in the environmental
water was controlled to 2.5 ppm by stopping air from being
blown into -the fresh sea water in the control tank.
The results of the above-mentioned experiments are
shown in Table 1.
Table 1
. . . . . . . ~. . .
Example Ccmparison Examples
I t e m s 1 1 2 3 4 5 6
. . .. __
Density (kg/m3) 400 96 400 400 400 400 400
Temperature (C) 10 10 25 10 10 10 10
Concentration (pprl)
10 days after start of experiment
Ammonia compounds 2 1.8 3 21 2 2 2
Water-soluble organic compounds 12 10 15 12 160 12 12
Carbonic acid radical 165 160 185 180 165 1200 165
Molecular oxygen 6.5 7.0 5.5 6.5 6.5 6.5 2.5
. .
Percentage of prawns kep-t alive
1 day after start of experiment 100 100 98 92 98 96 96
2 days after start of experiment 100 96 94 88 95 92 86
3 days after s~rt of experiment 100 10 92 91 88 84 80
5 days after start of experument 99 83 84 72 83 76 76
10 days after start of experiment 97 74 70 48 78 62 72
.
Example 2
Procedures identical to those in Example 1 were
carried out in Example 2, except that 1000 young red sea
breams (chrysophrys major) each having an average weight of
- 24 -
~071~18~
40g were placed in the water tank 1 at a density of 320 kg
per m3 of the enviroumental water and the temperature of
the environmental water was controlled to 8C. The results
of Example 2 are shown in Table 2.
13xample 3
The same procedures as those used in Example 1 were
eEfected except that 1600 young carps having an average
weight of 25g were placed in the water tank 1 at a density
of 320 kg per m3 of the environmental water supplied from a
city water system, and the environmental water was adjusted
to a tempera-ture of 15C. The results of Example 3 are
shown in Ta~le 2.
Table 2
. .
_ I t e m s _Example 2 Example 3
Type of fish Red sea bream Carp
Average weight of fish (g) 40 25 -
Temperature of enviroNmental water (C) 8 15
.
Concentration (ppm) -
10 days after start of experiment
~rmonia compounds 2.5 2.0
Water-soluble organic cam~ounds 14 15
Carbonic acid radical 170 65
Molecular oxygen 6.4 6.8
. .. .
Percentage of fish kept alive
1 day after start of experiment 100 100
2 days after start of experiment 100 100
3 days after start of experiment 100 99
5 days after start of experiment 98 98
10 days after start of experiment 97 91
~7~
Example 4
The apparatus shown in Fig. 2 was employed in Example
4. The water tank 1 exhibiting an inside volume of 27
liters (30cm x 30cm x 30cm) was charged with fresh sea
water and 320 prawns (Penaeus japonicus) each having an
average weight of 30g. The density of the prawns in the
environmental water was 350 kg/m3. The withdraw pipe line
3 and -the return pipe line 7 were made of polyvinyl chloride
pipes. The environmental water withdrawn from the water
tank 1 was adjusted to a temperature of about 10C in the
control path 2 and then returned back into the water tank
1. In the control path 2, air was blown and bubbled into
the environmental water for maintaining -the molecular
oxygen and the carbonic acid radical dissolved in the
environmental water at levels of between 5 and 8 ppm and
150 and 190 ppm, respectively. In order to eliminate the
ammonia compounds from the environmental water, about 45 kg
of natural zeolite particles each of from 0.3 to 0.5 cm in
si2e were packed in a net made of polyvinylidene chloride
and placed into the control path 2. Also, in order to
eliminate the water-soluble organic compounds from the
environmental water, 9 kg of activated carbon particles
each of from 0.2 to 0.5 cm in size were packed in a net
made of polyvinylidene chloride and immersed into the
environmental water in the control path 2. The above-mentioned
adsorbing materials were replaced with fresh ones at intervals
of every 12 hours for maintaining tl.e ammonia compounds and
the water-soluble organic compounds in the environmental
water at total concentrations of 3 ppm or less and 15 ppm
or less, respectively. The persentages of the animals kept
- 26 -
~ ~7~ Ei 9
alive are shown below.
Period in which animals
are kept a]ive (day) Percent
.
12 96
18 95
93
The changes in appearance and appetite of the prawns
during the experimental period of time were observed over
a period of 30 days. No changes in both conditions were
found. It was also found that the loss in weight of the
live prawns during the experimental period of 30 days was
4% based on the weight of the live prawns at the s-tart of
the experiment. From this fact it is obvious that the
commercial loss due to keeping the prawns alive for a long
period of time is very small.
Examples 5 and 6 and
Ccmparison Examples 7 through 9
In Example 5, the same procedures as those used in
Example 4 were effected except that 50 adult conger eels
each having an average weight of 260 g were placed in the
water tank 1 so that the density of the conger eels became
480 kg per m3 of the environmental water. Furthermore the
temperature of the environmental water was adjusted to that
of 10C, and the adsorbing materials for the ammonia compounds
and the water-soluble organic compounds were replaced by
fresh ones at intervals of every 12 hours.
In Example 6, the same procedures as those used in
Example 5 were effected except that the adsorbing materials
- 27 -
were replaced by fresh ones at intervals of every 24 hours~
In Comparison Examples 7 through 9, the same procedures as
those used in Example 5 were repeated except that the
adsorbing materials for the ammonia compounds and the water-
soluble organic materials were respectively replaced by
Eresh ones at intervals of every 24 hours and 36 hours in
Comparison Example i, every 24 hours and 12 hours in Comparison
Examp].e 8 and sodium carbonate was added to the environmental
water in Comparison Example 9.
1~ The results of Examples 5 and 6 and Comparison
Examples 7 through 9 are shown in Table 3.
Table 3
. . . . .
Example Comparison Example
I t e m s 5 6 7 8 9
.~
Concentration (ppm)
10 days after start of experiment
Ammonia compounds 4.2 12.8 21.0 5.5 5.8
Water-soluble organic compounds 26 48 45 160 33
Carbonic acid radical 380 620450 360 1050
molecular oxygen 6.5 5.86.8 6.2 4.5
Percentage of fish kept alive
1 day after start of experiment 100 100 100 100 100
3 days after start of experiment100 99 94 96 92
5 days after start of experiment100 96 88 90 83
10 days after start of experiment 98 92 75 82 74
15 days after start of experim~nt 94 90 60 71 55
Examples 7 through 13
The apparatus shown in Fig. 3 was employed in each
of Examples 7 through 13.
- 28 -
~'70~39
In Example 7, test water containing 2 ppm of ammonia
compounds and 20 ppm of water soluble organic compounds was
prepared in the water tank 1 by polluting fresh sea water
with dead flatfishs (Paralichthys olivaceus) and dead carps
(Cyprinus carpio).
Referring to the control path 2 shown in Fig. 3, the
zone 12 for containing an adsorbing agent for the ammonia
compounds was filled with 280 g of natural zeolite particles
each of 3 mm in size, and the zone 13 for containing an
adsorbing agent for the water-soluble organic compounds was
charged with 160 g of activated carbon particles each of
3 mm in size. In addition, the means 34 for receiving an
agent for decomposing an oxidizing agent was charged with
160 g of actuated carbon particles each of 3 mm in size.
An aqueous solution of sodium hypochlorite as an oxidiæing
agent was contained in the tank 31.
The test water was recycled at a flow rate of 6 liters/hr.
through the water tank 1, the control path 2, the withdraw
pipe line 3 and the return pipe line 7. The sodium hypochlorite
solution was mixed with the test water at the outlet end
portion of the withdraw pipe line 3. The test water forwarded
to the control path 2 passed through zones 12, 13 and 34,
and then was adjusted to a temperature of 10C by the
temperature control means 10. The returned test water was
polluted again with the dead flatfish and dead carps in the
water tank 1.
A~ter recycling the test water for hours, a portion
of the test water was sampled at a point A in the outlet
end portion of the withdraw pipe line, and subjected to the
determination of the concentration of the oxidizing agent
- 29 -
~)7~ 9
in the test water.
Another portion of the test water was sampled at a
point B in the outlet end portion of the zone 12 containing
the adsorbing agent for the ammonia compounds, and subjected
to -the determination of the concentration of the ammonia
compounds.
Still another portion of the test water was sampled
at a point C in the outlet end portion of the zone 13
containing the adsorbing agent for the water-soluble
organic compounds, and subjected to the determination of
the concentration of the water-soluble organic compounds in
the test water.
A further portion of the test water was sampled at a
point D in the outlet end portion of the zone 34 containing
the decomposing agent for the oxidizing agent, and subjected
to the determination of the oxidizing agent ln the test
water.
The eliminating rates (mg/hr) of the ammonia compounds
and of the water-soluble organic compounds were calculated
from the results of the above-mentioned determinations.
In Example 8, the same procedures as those used in
Example 7 were effected except that 200 g of aluminium
alumino-silicate particles having a ratio of A12O3:SiO2 of
23:75 and of particle size of 3 mm were used in place of
the natural zeolite as the adsorbing agent for the ammonia
compounds.
In Example 9, the same procedures as those used in
Example 7 were effected, except that the test water was
recycled at a rate of 15 liters/hr., and 280 g of synthetic
zeolite (4A type) were used instead of the natural zeolite
- 30
89
as the adsorbing agent for the ammonia compounds.
`In Example 10, the same procedures as those used in
Example 7 were carried out, except that 560 g of aluminium
alumino-silicate were used in place of the natural zeolite
as the ammonia compound-adsorbing agent. Furthermore,
410 g oE the activated carbon were used for adsorbing the
water-soluble organic compounds, 410 g of the activated
carbon were used for decomposing the remaining oxidizing
agent, and hydrogen peroxide in place of the sodium hypochlorite
was used as the oxldizing agent.
In Example 11, the same operations as those used in
Example 10 were conducted except that 160 g of a weak acid
type cation-exchange resin were used in place of the aluminium
alumino-silicate, and water from a city water system was
used in place of the sea water.
In Example 12, the same procedures as those used in
Example 7 were carried out, except that water from a city
water system was used instead of sea water, and a small
amount of about 140 g of natural zeolite was employed
2Q therein.
In Example 13, the same procedures as those used in
Example 7 were performed except that 320 g of aluminium
alumino-silicate were used as the decomposing agent for the
remaining oxidizing agent, in place of the activated carbon.
The results of Example 13 are shown in Table 4.
Table 4 clearly shows that even with very small
concen-trations of the ammonia compounds (2 ppm) and of the
water-soluble organic compounds (20 ppm), these compounds
could be eliminated with a relatively high degree of
efficiency. Also, it is evident that the remaining oxidizing
- 31 -
8~
I. ` U~
t~ h ~ ~ ~ N ~D ~ O O CO ~`1
~ -~1 r--I ~ ~ r--i O r~ N 01~ 0 r--i
~i ~ Ul O _ ~ D r~
r~
~ ~ ~ ~ co ~r Ln ~ ~D CO )
,, ~ 1~ r--l r--l
~ '
N ~ ~ ,_1 r-/ co ~c) ~) r-l ~
~D, o o o o o o o
~ '
O ~ o~ r o o ~ co
.~
~ u, m
t.) r ~ O ~ r--l ~r
~ ~ a~ ~ O O r--i r--i
N ~ ~ tl:lCO O O t~l Ct)
r~ ~ r~i 1~ t~ 1~ ~ ~i
'~ ~ ~ N N N N r--l r-l N
r~ r-l r-l r-l r-l r-l
r~ ) O O O O O O
0.,, ~. ~ m~
~ oJ~ o~ ~0~ ~0~ 0~
1~ ~ ~r-l ~r~ t rl ~r--l r-l ~r--l ~D 3 ~IN
~1 ' r~3 rc~ r~ ra3 ra3 ~ 3
4~ ~ ~ ~ CJ~
~? O U U ~ ~
O ~
~ u~ ~ (I) O ~ a) ~ o
s:~ ~ ~ ~1 a) ~ I ~ rl O ~ I ~J ~1 1 ~ ~1 0 ~1 0
~1 ~ ~ o ~ o ~ o~ 3 ~ ~ ~ o~ ~ ~ o
O ~ ~ ~ ¢) N ~ 0 N
$ ~ $
0; 1 1- C~
-
- 32 -
- j
1~7~89
agent, that is, sodium hypochlorite and hydrogen peroxide,
could be decomposed with a high degree of efficiency.
Fur-thermore, it is evldent that the present invention is
effective not only for applica-tion to salt water (sea
water) but also for application to fresh water (river water
or city water).
Example 14
The apparatus shown in Fig. 3 was employed in Example
14, 1.2 kg of live prawns having an average weight of 30 g
wére placed ir, a water tank having an inside volume of 3
liters, and then -the water tank was filled wi-th sea water.
The density of the prawns was 400 kg/m3. The prawns (1.2 kg)
excreted 2.1 mg/hr of ammonia compounds and 2.4 mg of
water-soluble organic compounds per hourn Accordingly, if
the environmental water is kept for one week without eliminating
these compounds, it is expected that the concentrations of
ammonia compounds and the water-soluble organic compounds
in the environmental water will become as high as 98 ppm
and 112 ppm, respec~ively.
In the control path 2 in Fig. 3, the zone 12 was
charged with 200 g of synthetic aluminium alumino-silicate
having a ratio of Al2O3:SiO2 of 23:77 and a size of 3 mm
per particle; the zone 13 was charged with 160 g of activated
carbon of 3 mm in size per par-ticle; and the zone 34 was
charged with 240 g of activated carbon of 3 mm in size per
par-ticle. A solution of 3.25~ by weight of sodium hypochlorite
was stored in the tank 31. The environmental water was
recycled through the water tank 1, control path 2, withdraw
pipe line 3 and return pipe line 7 at a recycling rate of
6 liters/hr.
- 33 -
~ ~7a~899
The sodium hypochlorite solution was introduced into
the outlet end portion of the withdraw pipe line 3 at a
flow rate of 5 ml/hr by means of a feed pump 35 to be mixed
with the environmental water.
S It was determined that the concentrations oE the
portions oE the environmental water located just upstream
oE -the entrance of -the control path 2 and just downstream
of the outlet end of the zone 34 were 27.8 ppm and 0.3 ppm,
respectively.
The concentrations of the ammonia compounds, the
water soluble organic compounds, the molecular oxygen and
the carbonic acid radical in the environmen-tal water, and
the percentage of the prawns kept alive based on the initial
number thereof were 0.8 ppm, 7.6 ppm, 6.8 ppm, 260 ppm and
96% respectively, at the stage of a week after the start of
the experiment, and 1.0 ppm, 8.2 ppm, 6.6 ppm, 480 ppm and
93~ respectively, at the stage of two weeks after the
beginning of the experiment.
The dead prawns were removed from the environmental
water as soon as they were found.
In the comparison of the above-determined respective
concentrations of 0.8 ppm and 7.6 ppm of the ammonia compounds
and the water-soluble organic compounds with the preexpected
respective values of 98 ppm and 112 ppm of the same, it is
evident that the method and the apparatus of the present
invention are very effective for clarifying the environmental
water of aquatic animals.
The prawns kept for two weeks were in good health.
- 34 -
