JP2002034385A - Overland culture method by circulating culture water and apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an overland culture system and apparatus circulating the culture water, capable of shortening the culture period and improving the culture productivity without using chemicals and enabling the reduction of the apparatus size. SOLUTION: The culture apparatus for the overland breeding of fish and shellfish with seawater is composed of a breeding water tank 6 a biological treating apparatus 10, an ozone cleaning apparatus 11 and pipes connecting the above apparatuses to form a closed circuit. The treating apparatus 10 is provided with a packed layer holding a carrier 20 supporting nitrifying bacteria at a high concentration, a filter material to capture suspending substance and a supporting material 21 in three layers and a cleaning nozzle placed in the middle or at the bottom of the packed layer. The cleaning apparatus 11 has an inlet port to introduce a mixed gas 17 of ozone 18 and air 15 at the lower part. The pipe connecting the apparatus 10 and the apparatus 11 is successively connected with a pipe 14 to directly circulate to the breeding water tank 6 and a pipe 5 to introduce clean seawater obtained by the precision filtration of sand-filtered seawater. The ozone cleaning apparatus may be provided with a contact tank 12 to remove the generated oxidant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terrestrial aquaculture system for fish and shellfish, and more particularly to a method and apparatus for cultivating seafood on land while circulating breeding water using seawater.

[0002]

[Prior Art] Due to environmental hormones and marine pollution,
The catch of marine products and the production of high-quality fish are decreasing. As a countermeasure, research and development of aquaculture technology on land is being promoted in order to stably supply safe seafood.
Conventionally, in the marine aquaculture of marine products, in the area where clear seawater can be obtained, the seawater has been used as it is, or flounder and red sea bream have been cultivated by pouring sand-filtered seawater. Therefore, a large amount of breeding wastewater mixed with fish and shellfish dung and urine, and garbage is discharged into the sea area, causing marine pollution of fishing grounds. In recent years, as a countermeasure,
"Research and development of an environment-creating closed-circulation onshore aquaculture system" that minimizes the amount of wastewater has been promoted.

[0003] The conventional onshore cultivation system for circulating breeding water uses a biological treatment tank of about one third of the capacity of the breeding aquarium to nitrify ammonia-nitrogen and nitrite-nitrogen to further remove nitric acid generated. Generally, a method of treating in a nitrogen tank (biological removal of nitrogen gas by adding a nutrient such as ethanol) is common. In this system, the installation space of the circulation equipment (purification equipment) is larger than that of the breeding aquarium, and it is difficult to manage the operation of the equipment (water quality management) by increasing the feed supply according to the growth of fish and shellfish, Such as the high rate of breeding water exchange,
There are many problems. In addition, in the marine aquaculture system for marine aquaculture, a large amount of fish and shellfish are stored in the breeding aquarium in order to improve productivity. A large amount of ammonia is generated, and at the same time, a viscous liquid is generated due to the stress of fish and shellfish, which further deteriorates the rearing environment.

[0004] Therefore, after the breeding aquarium, a foam separation tank,
A nitrification tank and a denitrification tank, which are biological treatment tanks, an ultraviolet sterilizer and an ozone sterilizer for sterilizing harmful microorganisms in the breeding water are installed, and the system uses the breeding water in circulation. In such a system, ammonia is usually converted into nitric acid via nitrous acid mainly by using an organism, and nitric acid is converted into nitrogen gas by using an organism. Biological methods generally require the use of drugs that are harmful to the human body, instead of taking a long time to perform their functions and constantly maintaining their biological activities. In businesses that require strong economics, such as the aquaculture industry, it is important to rationalize the cost of equipment and maintenance.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and is capable of shortening the culturing period and improving the culturing productivity without using chemicals, and furthermore, reducing the size of the apparatus and managing the operation in accordance with the growth. It is an object of the present invention to provide a breeding water circulation type onshore aquaculture method and apparatus that are easy to use.

[0006]

According to the present invention, there is provided a method of cultivating fish and shellfish on land while circulating the breeding water using seawater. The nitrification treatment is carried out by supplying the nitrification bacteria to the biological treatment step, and a part of the nitrification treatment water is circulated as it is, and the remaining part is ozone treated and circulated, or the entire nitrification treatment water is ozone treated. It is a breeding water circulation type land aquaculture method characterized by circulation. In the breeding water circulation type onshore culture method, sand-filtered seawater is supplied to the nitrification-treated water before the ozone treatment by precision filtration, and the supply amount can be 5 to 10% by volume of the breeding water amount.
The breeding water is circulated as follows: ozonated water: nitrified water:
It can be performed at a rate of 0 to 3.

Further, according to the present invention, there is provided an aquaculture apparatus for rearing fish and shellfish on land in a breeding aquarium, a biological treatment apparatus, an ozone purifying apparatus, and seawater in which these are sequentially connected by piping to form a circulation path. The biological treatment apparatus has a packed bed filled with three layers of a carrier for holding nitrifying bacteria at a high concentration, a filter medium for capturing suspended substances, and a support material, and a washing nozzle in the middle or lower part of the packed bed. The ozone purifier has an inlet for introducing a mixed gas of ozone and air at a lower portion, a pipe connecting the biological treatment apparatus and the ozone purifier, a pipe circulating directly to a breeding aquarium, and a sand pipe. A breeding water circulation type onshore aquaculture apparatus characterized by sequentially connecting piping for introducing seawater obtained by precision filtration of filtered seawater. In the terrestrial aquaculture apparatus, the ozone purifying apparatus includes a reaction tank for introducing a mixed gas of ozone and air, a contact tank for removing an oxidant generated by a reaction between seawater and ozone, and a mixed gas of ozone gas and air for the reaction tank. And an ejector to be introduced.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is to strictly control the water temperature and water quality on land to prevent pollution of fishing grounds due to marine aquaculture and the use of formalin, antibiotics and chemicals, which are problematic. In addition to restricting the use of chemicals that interfere with human health, the reduction of breeding wastewater contributes to environmental conservation in the sea area. Further, according to the present invention, the survival rate can be improved by isolating harmful protists from natural sea areas such as parasites, and the cultivation period can be shortened and the cultivation productivity can be improved by controlling the optimal breeding water temperature and water quality. The sterilization of breeding water with ozone, the removal of ammonia nitrogen, and the reduction of the size of the biological treatment device by the oxidation of nitrite nitrogen, the operation management according to the growth is easy, and the operation management that can be operated by the elderly is easy. Labor saving and simplification are achieved. Furthermore, there is no need for a chemical bath such as hydrogen peroxide or formalin, and it is possible to supply marine fish and shellfish that can be eaten with confidence to consumers.

The present invention makes use of the advantages of biological treatment and ozone treatment effectively, and chemically utilizes the oxidizing power and sterilizing power of ozone used in water purification plants to convert ammoniacal nitrogen into nitrogen gas. And the amount of generated nitric acid was reduced, and the denitrification tank was omitted. The nitrite generated in the biological treatment tank is time-consuming only by nitrification by living organisms (it is necessary to increase the residence time of the biological treatment tank). Was returned to the breeding aquarium, and the remaining nitrous acid was oxidized with ozone into nitric acid. Thereby, the size of the biological treatment tank can be reduced to 1/2 to 1/3 of the normal size. Conventionally, during the breeding period, as the seafood grows and the food intake increases, the ammonia concentration in the breeding water also increases, the amount of nitrite generated in the biological treatment tank increases, and organisms are used. The processing method makes it difficult to respond to this change. However, since the equipment needs to be constantly operated on the safe side, it is necessary to construct a large equipment, and the maintenance cost is also increased. In the system of the present invention, it is possible to cope only by controlling the injection amount of ozone, and it is not necessary to reduce the breeding density (the number of breeding animals per unit volume or the amount of fish and shellfish) more than necessary.

As the breeding water, sand-filtered seawater is subjected to microfiltration that does not allow bacteria and microorganisms and their eggs to pass therethrough, particularly seawater filtered through a hollow fiber membrane of 0.1 μm or less, and this seawater is circulated and used. To prevent the invasion of protozoa and pathogens contained in seawater. Seawater contains organisms and their eggs, pathogens and harmful chemicals that infest fish and shellfish,
They invade breeding water and hinder growth, cause disease, malformations, decrease survival rate, and reduce commercial value. However, in the present invention, it was confirmed that no measures such as administration of antibiotics for the occurrence of disease were required at all in order to prevent these inhibitors from entering the breeding water. Also,
When moving the breeding aquarium according to growth, it is preferable to add fresh water to the breeding water that has been bred so far, the addition ratio is
It is 10 to 20% per capacity of the breeding aquarium. Too much fresh water reduces the food intake of fish and shellfish and worsens growth. The supply amount of fresh water during circulating breeding is 5 to 10% per volume of the breeding aquarium.

[0011] The amount of circulating water for circulating land farming is also affected by the breeding season of fish and shellfish. However, in a normal biological treatment circulating system, the adult fish after the juvenile period has 20 to 30 turns per day (circulation). Volume / capacity of breeding aquarium). However, in the present invention, the number of turns is 8 to 12 per day, the size of the circulating pump may be about 削減, and reduction in the amount of electricity used has been confirmed. In the present invention, the circulation of the breeding water is characterized in that the mixing of the ozonized water and the biologically treated water is economical, and the mixing is performed. The mixing ratio is a ratio of the biologically treated water 0 to 3 to the ozone treated water 1. The circulation during the fry season circulates with ozonated water because the growth of fish and shellfish is remarkable and the amount of feed increases sharply. Mixing of biologically treated water starts at 100 days of age (days of breeding after hatching of fish and shellfish), and gradually increases the amount of biologically treated water to reduce the ratio of ozone-treated water to biologically treated water to 1: 1 to 3 I do.

In the biological treatment tank, anthracite (particle diameter: 1.2 to 3 mm) having a large surface area per unit volume or a plastic filter medium and a suspended substance are used as carriers in order to keep the growth density of nitrifying bacteria at a high concentration. Filter media (sand, etc., particle size 0.6 mm) for capturing and gravel (particle size 2-20) as a support material
mm). The filling height is 500 to 600 mm for anthracite and the like, and 10 for sand.
0 to 200 mm and the gravel are 100 to 200 mm. Further, an air washing nozzle for preventing clogging and a washing water (backwashing) nozzle passing through a 50 μm or 100 μm filter are provided in the middle or lower part of the packed bed. A part of the biologically treated wastewater is returned to the breeding aquarium, but a part is transferred to an ozone reaction tank and brought into contact with a mixed gas of ozone gas and air. The ozone gas discharged from the ozone generator is rapidly mixed by an air ejector and sent to the reaction tank. In the reaction tank, a gas collision plate is preferably provided in the reaction tank in order to make gas-liquid contact with wastewater efficiently.

Since the injection rate of ozone is affected by the quality of the waste water, the operation is performed while measuring the generated oxidant. The target value of the concentration of the oxidant is 0.5 mg / l. Bacteria in the breeding wastewater are sterilized by the generated oxidant, and ammonia nitrogen is removed as nitrogen gas by the action of the oxidant. Also, nitrous acid is oxidized to 8
0-95% is converted to nitric acid. Oxidants are consumed by biological disinfection in seawater and oxidizing action of substances, but are present in wastewater as residual oxidants. If this residual oxidant is returned to the breeding water as it is, it will cause damage to the fish and shellfish and must be removed. In the contact tank, the residual oxidant is brought into contact with activated carbon or carbide to remove the oxidant. The concentration of the residual oxidant in the ozonized water returned as breeding water is adjusted to be 0.003 mg / l or less.

Next, the present invention will be described with reference to FIG. 1 which is a schematic process diagram showing an example of the onshore aquaculture system of the present invention. FIG. 1 shows a rearing water tank 6, a rearing drainage pump basin 8, a circulation pump 9, a biological treatment tank 10, an ozone reaction tank 11, and a contact tank 1.
2, and a fine filter 2, a new water storage tank 3, a new water supply pump 4, an air blower 15, an ejector 17, an ozone generator 18
It is composed of The breeding water is received in the fresh water storage tank 3 from the sand filtration seawater pipe 1 through the 0.1 μm hollow fiber membrane fine filter 2, and supplied to the breeding water tank 6 via the ozone reaction tank 11 and the contact tank 12. You. The breeding drainage 7 is guided to a breeding drainage pump basin 8 and transferred to a biological treatment tank 10 by a circulation pump 9. The breeding drainage pump basin 8 can be provided with a foam separation device to remove the viscosity of drainage.

In the biological treatment tank 10, a carrier 20 (anthracite or plastic filter medium) for keeping the growth density of nitrifying bacteria at a high concentration is provided on an upper part, and sand for capturing suspended substances and a filter medium support material are provided on a lower part. The gravel 21 is filled, and the ammonia in the waste water is nitrified and the suspended matter is removed. The treated water obtained by nitrifying the ammonia in the biological treatment tank 10 to such an extent that the breeding of fish and shellfish is not hindered is returned to the breeding aquarium 6 through a return pipe 14. In addition, a part of the breeding wastewater is guided to the ozone reaction tank 11 and brought into contact with a mixed gas of ozone from the ozone generator 18 and air from the air blower 13 to sterilize the breeding wastewater with the generated oxidant and to remove unnitrified wastewater. Ammonia and nitrous acid are oxidized and removed. The wastewater containing the oxidant is further led to the contact tank 12, where it is brought into contact with activated carbon or carbide so that the residual oxidant is reduced to 0.003 mg / l or less, and then returned to the breeding aquarium 16 by the return pipe 13.

[0016]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples. Example 1 25 days after hatching and 3 days after hatching using the system of the present invention shown in FIG.
300 to 1,100 juvenile tortoises on the 8th were bred on land for 5 to 12 months by circulating breeding water in a breeding aquarium.
Apparatus, breeding aquarium 5 m ³ to 2 tank, foam separation tank (breeding drain pump squares) 2 bath, and 2 tank biological treatment tank 0.42 m ³ 0.
84 m ³ in one tank, one ozone reaction tank, one contact tank, a microfilter for fresh water replenishment, an ozone generator and a circulation pump,
An air blower was installed and used. Before feeding the fry, the sand-filtered seawater was filtered through a precision filter equipped with a hollow fiber membrane of 0.1 μm in the breeding aquarium, and then reacted with ozone in an ozone reactor, and passed through a contact tank filled with activated carbon to 5 m ^3. Was filled with breeding water. Thereafter, 1,100 juvenile tortoises, 38 days old, were introduced.

The biological treatment tank has a capacity of 0.42 m ³ for 47 days.
The tank was operated, and from day 48, 0.42 m ³ was operated in two tanks. During this time, the amount of oxidant generated in the ozone reaction tank was 0.2 to 0.5 mg / l, and the residual oxidant at the outlet of the contact tank was 0.001 to 0.003 mg / l. FIG. 2 shows the change of NH ₃ —N during operation, FIG. 3 shows the change of NO ₂ —N, and FIG. 4 shows the change of NO ₃ —N during operation. Ammonia nitrogen (NH ₃ -N) peaks after one month in both breeding water and biologically treated water, but stabilizes at 0.2 mg / l or less after two months. Nitrite nitrogen (NO
_2- N) indicates that the biologically treated water reaches a peak after two months,
Although it becomes 1.5 mg / l, the breeding water is stable at 0.5 mg / l or less. Nitrate nitrogen (NO ₃ -N), the breeding water, biologically treated water, gradually increases with ozonated water. However, the rate of rise was slow and there was no need for denitrification.

From the above results, even if the capacity of the biological treatment tank is set to 8 to 17% of that of the breeding aquarium, the ammonia nitrogen and the nitrite nitrogen, which are toxic to fish and shellfish, are removed in the ozone reaction tank. In this example, 50 to 90% of ammonia nitrogen and 70 to 95% of nitrite nitrogen could be removed in the ozone reactor. The biological treatment tank used in this example is a cylindrical (or square) water tank having a capacity of 0.42 m ³ and a capacity of 0.84 m ³ . Carrier (anthracite particle size 1.2 ~
3 mm: plastic filter media may be used) 500 mm, sand in the middle to capture suspended matter (particle diameter 0.6 mm)
Is filled with three layers of gravel (particle size: 2 to 20 mm) as a support material of 100 mm at the bottom and 100 mm, and breeding effluent flows in from the upper part and comes into contact with the carrier in a downward flow. Air washing was carried out with a washing nozzle provided at the bottom of the support material, and back washing was carried out with seawater passed through a 50 μm filter.

The ozone reaction tank and the contact tank used in this example were water tanks having a rectangular integrated structure, with a reaction tank on the inflow side and a contact tank on the outflow side. The reaction tank was allowed to react by flowing ozone gas, which is a mixture of biologically treated water and air, from the bottom. The contact tank was filled with activated carbon, and contacted with biologically treated water mixed with ozone gas in an upward flow to remove residual oxidants. The ozone injection amount is
At the outlet of the reaction tank, the amount was adjusted to 0.5 mg / l or less, and the residual oxidant at the outlet of the contact tank was measured. As a result, the concentration of the oxidant was 0.2 to 0.5 mg / l at the outlet of the reaction tank and 0.001 to 0.003 mg / l at the outlet of the contact tank throughout the year.

Example 2 In the same manner as in Example 1, breeding water and fresh water for replenishing the breeding water were subjected to filtration of sand-filtered seawater with a microfilter equipped with a hollow fiber membrane of 0.1 μm, followed by ozone treatment. As a result of using seawater from which a residual oxidant was removed through a contact tank filled with activated carbon by reacting with ozone in a reaction tank, fry (about 0.5 g)
Although it was cultivated on land up to the size of a commercial product of 600 to 800 g, no mortality occurred due to diseases such as parasites or viruses.

Example 3 In Examples 1 and 2, when the operating conditions of the breeding water (conditions of the amount of circulating water) were changed, the results were obtained in which the amount of feeding of the tiger puffer fluctuated due to the change in the water quality. Reduced food consumption has a significant effect on the growth of seafood. Table 1 shows a comparison of the amount of food consumed depending on the circulating conditions of the breeding water.

[Table 1]

The above results were obtained by changing the conditions of fresh water (3%) and ozone-treated water (97%). Even when the biologically treated water was mixed with the ozone-treated water, the food consumption did not decrease. , Proved to be increasing. Therefore, it is not necessary to circulate the breeding water in its entirety by reacting it with ozone, and the circulating amount may be determined by the quality of the breeding water (the concentration of ammonia and nitrite), and the equipment can be economically designed. According to the present embodiment, the design values of ozone-treated water: biologically treated water are set to 1 to 3 as a design value.

[0023]

In recent years, stable fishery resources have been challenged due to factors such as a decrease in catches due to changes in the marine environment, overfishing at sea level, and deterioration of fishing grounds due to emission of harmful substances such as environmental hormones. In the aquatic world, the circulating onshore cultivation system for breeding water has a low drainage, eliminates overcrowding on the sea surface, not only improves the environment in the sea area, but also has excellent water quality and water temperature management. It is expected that seafood can be supplied to consumers stably throughout the year. The present invention, by adopting the above-described configuration, has the following problems as a recirculating onshore aquaculture system: "removal of ammonia and the like (trimorphic nitrogen)", "reduction of the aquaculture period by controlling water quality and temperature", " Clearing the control of fish diseases and parasites that hinder growth, and contributing to food and environmental issues as a compact system.

[Brief description of the drawings]

FIG. 1 is a schematic process diagram showing an example of a land culture system of the present invention.

FIG. 2 is a graph showing a change in NH ₃ —N by treated water.

FIG. 3 is a graph showing a change in NO ₂ -N due to treated water.

FIG. 4 is a graph showing a change in NO ₃ -N due to treated water.

[Explanation of symbols]

1: Sand filtration seawater pipe, 2: Microfilter (hollow fiber membrane), 3:
New water storage tank, 4: New water supply pump, 5: New water supply pipe, 6:
Breeding aquarium, 7: breeding drainage pipe, 8: breeding drainage pump basin,
9: circulation pump, 10: biological treatment tank, 11: ozone reaction tank, 12: contact tank, 13: ozone-treated water return pipe, 14:
Biological treatment water return pipe, 15: air blower, 16: air pipe,
17: ejector, 18: ozone generator, 19: ozone tube, 20: carrier layer, 21: packed bed of sand and gravel

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C02F 1/50 540 C02F 1/50 540B 550 550B 550C 550H 560 560B 560E 560H 560Z 1/78 1/78 3/06 3 / 06 3/34 101 3/34 101D 9/00 501 9/00 501B 502 502E 502H 502R 502Z 503 503C 504 504A 504D 504E (72) Inventor Toru Umeda 11-1 Haneda Asahimachi, Ota-ku, Tokyo Ebara Corporation F term (reference) 2B104 EA01 EF01 EF09 EF13 4D003 AA01 AB02 BA02 CA02 CA10 DA18 DA22 EA01 EA22 EA23 EA30 FA02 FA05 FA06 4D040 DD03 DD14 DD31 4D050 AA06 AA08 AB06 AB35 AB37 BB01 CB02 BD02 BD03 CA06 BD06

Claims (5)

[Claims] 1. A method of cultivating seafood on land while circulating breeding water using seawater, wherein a part of the breeding water is extracted and supplied to a biological treatment step having nitrifying bacteria for nitrification treatment. A part of this nitrification treatment water is circulated as it is,
A breeding water circulation type land farming method characterized by circulating the remaining part by ozone treatment or circulating the entire nitrification treatment water by ozone treatment. 2. The aquaculture method according to claim 1, wherein the sand-filtered seawater is finely filtered and supplied to the nitrification-treated water before the ozone treatment, and the supply amount is 5 to 10% by volume of the breeding water amount. Characteristic land culture method of breeding water circulation type. 3. The breeding water circulation type land culture method according to claim 1 or 2, wherein the breeding water is circulated in a ratio of ozone-treated water to nitrification-treated water in a ratio of 1: 0 to 3. 4. A breeding aquarium, a biological treatment device, an ozone purification device, and a cultivation device for breeding seafood by land in seawater, wherein the circulating route is formed by sequentially connecting these with piping,
The biological treatment apparatus includes a packed bed filled with three layers of a carrier that holds nitrifying bacteria at a high concentration, a filter medium that captures suspended substances, and a support material, and a washing nozzle in the middle or lower part of the packed bed. The ozone purifier has an inlet for introducing a mixed gas of ozone and air at a lower portion, and a pipe connecting the biological treatment apparatus and the ozone purifier, a pipe circulating directly to a breeding aquarium, A breeding water circulation type onshore aquaculture device, which is sequentially connected to a pipe for introducing seawater obtained by finely filtering sand-filtered seawater. 5. A reaction tank for introducing a mixed gas of ozone and air, a contact tank for removing an oxidant generated by a reaction between seawater and ozone, and a mixed gas of ozone gas and air in the reaction tank. The breeding water circulation type land culture apparatus according to claim 4, further comprising an ejector for introducing the breeding water.