KR20230059913A - Closed recirculating aquaculture system - Google Patents

Abstract

The present invention is to provide a closed circulation filtration aquaculture system that can suppress marine pollution due to discharged water by reusing new breeding water, is free from space restrictions due to low need for seawater supply, and has high fish productivity compared to cost. The closed recirculation filtration aquaculture system according to the present invention enables eco-friendly aquaculture and has less space restrictions due to less need for new seawater supply. In addition, since breeding water is circulated and filtered for repeated use, it is economical, and it is possible to block pathogens from seawater, enabling stable aquaculture and increasing production.

Description

Closed circulation filtration aquaculture system {CLOSED RECIRCULATING AQUACULTURE SYSTEM}

The present invention relates to a closed circulation filtration aquaculture system including a flow control tank, a continuous batch reaction tank, a continuous batch treatment tank, a discharge tank, and an aquaculture tank, and in particular, marine pollution caused by discharged water by filtering, sterilizing, and reusing the breeding water in the tank. It relates to a closed circulation filtration aquaculture system with high productivity by enabling stable aquaculture without supplying new seawater.

The domestic fishing boat fishery has been continuously declining since 1986 due to a sharp decrease in fishing resources such as squid, mackerel, hairtail, and croaker. Due to the decrease in fish stocks due to overfishing, the reduction of fishing grounds due to climate change, and environmental pollution, it has not been possible to secure a catch above a certain level for the past 30 years. Accordingly, it is predicted that the amount and importance of aquatic products produced by the aquaculture industry will increase further in the future, and aquaculture technology that can reduce costs and energy and improve the growing environment is attracting attention to increase aquaculture products.

Among domestic fish farming, the production of saltwater fish and freshwater fish is 3:1, and the production of saltwater fish is much higher than that of freshwater fish. It is a method of cage farming, in which fish are accommodated and raised in a cage, and its productivity is gradually decreasing.

Domestic fish farming is highly dependent on the natural environment and is open to external water systems, so it is vulnerable to environmental changes and productivity is easily influenced. In addition, waste products from farmed fish are continuously discharged into external water systems, destroying the ecosystem and causing environmental pollution. It is likely to cause disease in farmed fish.

Therefore, it is necessary to introduce a recirculation aquaculture system (RAS) that is independent of the environment and environmentally friendly for a sustainable and high value-added aquaculture industry.

However, the existing circulation filtration aquaculture system requires a certain amount of water exchange every day depending on the turnover rate and operation method, and accordingly, discharge is also periodically generated. For such return water and discharged water treatment, there is a spatial restriction to be located in a place where seawater supply is relatively easy, and a discharged water treatment process must be separately prepared.

Recently, as interest in food safety, environmental protection, sustainability, etc. has increased internationally, there is a strong demand for implementation of international aquaculture standards, such as management and restriction of antibiotic use, management of aquaculture feed use, and request for implementation of sustainable aquaculture certification. In particular, consumption of marine products in Korea ranks first in the world with an average annual consumption of more than 60 kg, and raw seafood is the main source of raw fish in the diet, so there is a need for hygienic production because food pathogenic microorganisms can originate from aquaculture products. there is. In addition, drugs such as antibiotics are misused and abused for the treatment and prevention of fish diseases, and drug components are concentrated in the body of fish and indiscriminately discharged during wastewater treatment, causing various problems in the surrounding ecosystem.

Therefore, there is an increasing need for a closed circulating filtration aquaculture system (Closed RAS) that does not require water return and discharge water treatment, enables eco-friendly aquaculture, and has relatively little space constraints.

Korean Registered Patent Publication No. 10-1675718 discloses a circulating filtration type breeding water supply system that re-filters and sterilizes the discharged water used in aquaculture and reuses it as breeding water. A closed circuit circulating filtration type breeding water automatic supply device is described. However, since the above invention still involves the inflow of a certain amount or more of breeding water from the outside, a new system for solving these disadvantages is required.

Therefore, it is expected that it can be widely applied in related fields if the need for new seawater supply is small and a closed circulation filtration system capable of reusing breeding water is provided.

The present invention is to provide a closed circulation filtration aquaculture system that can suppress marine pollution due to discharged water by reusing new breeding water, is free from space restrictions due to low need for seawater supply, and has high fish productivity compared to cost.

According to one aspect of the present invention, a continuous batch type reaction tank into which water discharged from the aquaculture tank containing water is introduced; a filter for filtering water discharged from the continuous batch reactor; and a discharge tank for receiving and storing the water that has passed through the filter so that a constant flow rate of water can be introduced into the aquaculture tank.

The closed recirculation filtration aquaculture system according to the present invention enables eco-friendly aquaculture and has less space restrictions due to less need for new seawater supply. In addition, since breeding water is circulated and filtered for repeated use, it is economical, and it is possible to block pathogens from seawater, enabling stable aquaculture and increasing production.

1 is a schematic diagram of a closed circulation filtration aquaculture system of the present invention.
Figure 2 shows one implementation of the closed recirculation filtration aquaculture system of the present invention.
Figure 3 shows dissolved inorganic nitrogen and dissolved inorganic phosphorus in black sea bream and red sea bream breeding tanks.
Figure 4 shows the total length and weight of black sea bream and red sea bream.

Hereinafter, preferred embodiments of the present invention will be described. However, the embodiments of the present invention may be modified in various forms, and the scope of the present invention is not limited to the embodiments described below.

According to the present invention, since the water discharged from the aquaculture tank can be circulated and filtered and used repeatedly, there is less space restriction and no additional supply of seawater is required, so a closed circulation filtration aquaculture system capable of stable aquaculture is possible because it can block pathogens entering from seawater. Provided.

More specifically, the present invention provides a continuous batch reactor into which water discharged from an aquaculture tank containing water is introduced, a filter for filtering the water discharged from the continuous batch reactor, and the water that has passed through the filter is supplied and stored to the aquaculture tank. Provided is a closed recirculating filtration aquaculture system including an outflow tank that allows a constant flow rate of water to be introduced.

An exemplary closed recirculation filtration aquaculture system of the present invention is shown in FIG. 1 .

The continuous batch reaction tank of the present invention can perform a continuous batch process by introducing water discharged from the aquaculture tank.

In the continuous batch-type process, mixing, aeration, anaerobic, and precipitation processes are repeatedly performed, and the continuous batch-type reactor can simultaneously perform mixing, aeration, anaerobic, and precipitation processes, thereby removing phosphorus and nitrogen. Phosphorus and nitrogen removal efficiency can be increased by controlling the execution time of the process in the continuous batch reactor. In the continuous batch process, the aeration process may be performed for 15 minutes to 30 minutes when performed once, and the time required for performing the mixing, anaerobic and precipitation processes is not limited, but the continuous batch process may be performed for 120 minutes to 240 minutes. It may be carried out, preferably for 120 to 150 minutes.

The continuous batch reactor may further include an aerator and an agitator motor for performing the process, and the removal efficiency may be further increased by adding microorganisms capable of decomposing phosphorus and nitrogen in seawater and marine sediments. As the microorganism, a Bacillus aryabhattai strain, a Vibrio neocaledonicus strain, and a mixed strain thereof may be used.

In addition, a plurality of the continuous batch reactors may be connected in parallel, and phosphorus and nitrogen contained in the water discharged from the aquaculture tank may increase the removal efficiency as the number of consecutive batch processes increases. The continuous batch process is preferably performed 6 to 8 times for 24 hours, but is not limited thereto and may be repeated as many times as necessary for water purification.

The filter of the present invention can lower the turbidity of the water treated in the continuous batch reactor and filter out solid impurities. Specifically, the filter used in the present invention can be filtered by water pressure, and may be a fiber filter, a sand filter, etc., but is not limited thereto, and any filter capable of filtering solid impurities can be used without limitation. For example, a fiber disk filter (Yoocheon Enviro Co., Ltd.) having a 5 μm air gap may be used.

The filter can be automatically cleaned without supplying additional power through a backwashing process. In addition, when the flow rate discharged from the continuous batch type reaction tank excessively lowers the water level of the reaction tank, power supply to the motor of the filter may be automatically stopped.

The water level of all water tanks can be recognized by a water level sensor. If the water level in the tank is too low, the amount of water the tank drains can be reduced.

The discharge tank of the present invention is a tank for receiving and storing the water that has passed through the filter, and can be maintained at an organic concentration of 60 ppm or less, a phosphorus concentration of 5 ppm or less and a nitrogen concentration of 1 ppm or less, and a constant flow rate of water into the aquaculture tank can infiltrate.

At least one of the continuous batch reaction tank, discharge tank, and aquaculture tank may include one or more discharge valves for controlling the amount of water introduced and discharged.

In addition, the closed circulation filtration aquaculture system of the present invention may further include a treatment tank for receiving and storing the water discharged from the continuous batch reaction tank and discharging the stored water to the discharge tank, wherein the filter is connected to the treatment tank It may be provided between discharge tanks. By storing water in the treatment tank, it is possible to adjust the flow rate of the continuous batch type reaction tank and the discharge tank.

Furthermore, between the aquaculture tank and the continuous batch reactor, a flow control tank for receiving and storing the water discharged from the aquaculture tank and supplying a certain amount of inflow water to the continuous batch reactor may be further included. The flow control tank is equipped with a water level control sensor, and accordingly, it is possible to maintain a constant water level by adjusting the supply and discharge of water.

The closed circulating filtration aquaculture system reproduces fish at a high density by reusing water. In this process, wastes in the reused breeding water may accumulate and affect the productivity of the system, so sterilization of water is essential.

The sterilization method includes a method of treating chemicals, a method of using ozone, and a method of using ultraviolet rays. However, in the closed circulating filtration system, since each tank is organically connected, it is difficult to sterilize by treating chemicals. there is. In addition, when seawater is used, when ozone is used as a sterilizer, it can combine with bromine (Br) in seawater to form bromine compounds, resulting in toxicity. Therefore, it is preferable to sterilize using ultraviolet light.

Therefore, the closed recirculation filtration aquaculture system of the present invention may further include a UV sterilizer for sterilizing water before introducing water into the aquaculture tank.

Also, the water used in the present invention may be seawater. In the closed circulation filtration aquaculture system of the present invention, since the existing input seawater can be circulated and reused, it is economical compared to existing systems that necessarily require additional supply of a certain amount of seawater, and it does not necessarily need to be installed on the shore.

On the other hand, a breeding tank is a facility that actually stocks and manages fish, and the size or shape that satisfies various requirements such as the type of fish, physiological characteristics, purpose of aquaculture, and culture density must be determined, and the convenience of management, production cost, durability, etc. Therefore, it is possible to use a circular shape of the water tank for efficient operation of the system. In the case of using a circular water tank, there is an advantage in facilitating the flow and drainage of water.

On the other hand, the aquaculture tank may be provided with an air supply device capable of supplying oxygen to the water supplied from the discharge tank. Through this, the amount of dissolved oxygen (DO) in the aquaculture tank can be controlled and the amount of dissolved oxygen of 10 mg/L or more suitable for fish farming can be maintained.

When the aquaculture system of the present invention is installed outdoors, water level control and oxygen supply may be required due to seasonal and weather changes, so a water level control pipe, oxygen supply and diffusion device may be additionally included in preparation for an emergency.

Furthermore, a net may be additionally provided at an outlet through which water is discharged from the aquaculture tank to prevent fish from escaping or escaping from the aquaculture tank.

Hereinafter, the present invention will be described in more detail through specific examples. The following examples are merely examples to aid understanding of the present invention, and the scope of the present invention is not limited thereto.

Example

1. Implementation method

In order to compare and analyze the closed circulation filtration system (CRAS, experimental group) and the existing aquaculture system, flow-through (control) applied in the present invention, black sea bream and red sea bream were comparatively bred for 6 months using a circular tank with a capacity of about 7 tons. . In order to control the stocking density of fish, the quantity of water in the tank was adjusted to 5 tons for the flow-through type and 2.5 tons for the closed circulation filtration type, and by accommodating the same amount of fish, the closed circulation filtration type was made to have a density twice higher than the control flow-through type ( Table 1). The daily water exchange rate was adjusted to 500% (5 rotations/day), and the feed rate was 2 to 3% per body weight of the fish, which was supplied daily until sufficient intake.

[Table 1] Comparative experimental conditions of closed circulation filtration system and flow-through culture system

As the breeding conditions for the fish, the average water temperature was maintained at about 20 ° C, the average salinity was about 29 psu, and the dissolved oxygen was more than 5 mg / L for 6 months. A certain amount was collected every month and analyzed for ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, and phosphorus phosphate according to the marine environmental process test standards. In addition, 5 fish were caught every month, and the size and weight were measured for comparative analysis, and the survival rate of the fish was measured.

2. Results

The concentration of dissolved inorganic nitrogen (DIN), which is the sum of the concentrations of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen, and dissolved inorganic phosphorus (DIP) calculated as phosphorus phosphate are shown in FIG. 3 . Dissolved inorganic nitrogen and dissolved inorganic There was a slight difference in time, but no difference overall. That is, it was confirmed that the closed circulation filtration system of the present invention is no different from natural seawater suitable for fish growth.

After 6 months, the total length (Fig. 4a) and weight (Fig. 4b) of the black sea bream were 21.86 ± 1.36cm and 230.40 ± 60.08g in the flow-through control, and 21.84 ± 1.70cm and 213.50 ± 21.84 ± 1.70cm and 213.50 ± in the closed circulation filtration system It was 58.03 g, which was slightly lower in the closed circulation filtration type, but there was no statistically significant difference. After 6 months of raising red sea bream, the total length (Fig. 4c) and weight (Fig. 4d) were 30.16 ± 1.58 cm and 555.00 ± 69.34 g in the flow-through (control) and 31.54 ± 1.09 cm and 620.88 ± 72.14 g in the closed circulation filtration system, respectively. The expression was slightly higher, but there was no significant difference.

The number of dead individuals for 6 months was less than 5, and there was no significant difference in the survival rate of about 99% or more in the flow-through and closed circulation filtration systems.

[Table 2] Mortality and survival rate of black sea bream and red sea bream

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and variations are possible without departing from the technical spirit of the present invention described in the claims. It will be obvious to those skilled in the art.

1: water tank
2: inlet pump 1
3: inlet pump 2
4: flow control tank
5: flow control pump 1
6: flow control pump 2
7: continuous batch reactor
8: switching valve 1
9: switching valve 2
10: reactor pump 1
11: reactor pump 2
12: reactor pump 3
13: treatment tank
14: submersible motor
15: fiber filter
16: discharge tank
17 discharge pump 1
18 discharge pump 2
19: UV sterilizer
20: aerator
21: submersible motor
22: water level gauge in the flow control tank
23: water level gauge in the reaction tank
24: water level gauge in treatment tank
25: Water level gauge in the discharge tank
26: water thermometer
27: pH meter
28: electrical panel
29: PLC panel

Claims (14)

Continuous batch type reaction tank into which water discharged from the aquaculture tank containing water is introduced;
a filter for filtering water discharged from the continuous batch reactor; and
A discharge tank that receives and stores the water that has passed through the filter so that a constant flow rate of water can be introduced into the aquaculture tank
A closed circulation filtration aquaculture system comprising a.
According to claim 1,
The closed circulation filtration aquaculture system, further comprising at least one discharge valve for controlling the inflow, discharge, or both of at least one of the continuous batch reaction tank, discharge tank, and aquaculture tank.
According to claim 1,
Further comprising a treatment tank for receiving and storing the water discharged from the continuous batch reaction tank and discharging the stored water to the discharge tank, wherein the filter is provided between the treatment tank and the discharge tank.
According to claim 1,
Between the aquaculture tank and the continuous batch reactor, a flow control tank for receiving and storing the water discharged from the aquaculture tank and supplying a certain amount of inflow water to the continuous batch reactor,
The flow control tank is equipped with a water level control sensor,
Closed circulation filtration aquaculture system.
According to claim 1,
A closed circulation filtration aquaculture system further comprising a UV sterilization device for sterilizing water from which solid impurities have passed through the filter.
According to claim 1,
The continuous batch reactor includes an agitator, a closed circulation filtration aquaculture system.
According to claim 1,
The continuous batch reactor is a closed circulation filtration aquaculture system comprising a Bacillus aryabhattai strain, a Vibrio neocaledonicus strain, or a mixed strain thereof.
The closed recirculation filtration aquaculture system according to claim 1, wherein the water contained in the aquaculture tank is seawater.
Introducing water discharged from the aquaculture tank containing water into a continuous batch reactor;
Performing a continuous batch process in the continuous batch reactor;
filtering the water discharged from the continuous batch reactor;
introducing the filtered water into a discharge tank; and
The step in which the water discharged from the discharge tank is introduced into the aquaculture tank
Including, closed circulation filtration aquaculture method.
According to claim 9,
The continuous batch process is a closed circulation filtration method comprising mixing, aeration, anaerobic and precipitation processes.
According to claim 9,
The continuous batch process is performed repeatedly, the closed circulation filtration method.
According to claim 9,
The continuous batch process is carried out for 120 to 150 minutes, closed circulation filtration method.
According to claim 9,
The step of introducing the water discharged from the aquaculture tank into the continuous batch reactor
A closed circulation filtration aquaculture method, comprising the step of flowing water discharged from the aquaculture tank into a flow control tank and storing it, and the step of introducing the water discharged from the flow control tank into a continuous batch reaction tank.
According to claim 9,
Closed circulation filtration method further comprising the step of sterilizing the water discharged from the discharge tank using UV.

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