CN111587835A - A system and method for high-density ecological fish farming in circulating water - Google Patents

Abstract

The invention discloses a system and method for high-density ecological fish culture in circulating running water. The system includes a running water fish breeding pond, a purifying pond, a tail water purification pond, a ditch and a paddy field, and the inlet of the running water pond is connected with the purification pond. , the tail water discharge port is connected with the tail water purification tank, and between the purification tank and the tail water purification tank through the river ditch and the paddy field. After the water is pumped into the running water aquaculture pond, the fish excrement in the pond is involved in the center of the running water aquaculture pond under the action of the centrifugal force of the water flow. After sedimentation and separation, the tail water is purified by rice and aquatic plants and then used for running water culture Fish, the sedimented fish excrement is collected as fertilizer. The invention provides a method that combines traditional pond fish culture and flowing water fish culture technology, scientifically arranges the space and functions of paddy fields, river ditches, pond fish culture and water culture, comprehensively utilizes new culture facilities and technologies, and realizes efficient ecological fish culture. system and method.

Description

A system and method for high-density ecological fish farming in circulating water

technical field

The invention belongs to the technical field of aquaculture, and particularly relates to a system and method for high-density ecological fish culture in circulating water.

Background technique

At present, most traditional fish farming ponds lack scientific planning and layout due to early excavation, poor basic conditions, backward facilities and equipment, deep silt, lack of water quality treatment and aquaculture condition control equipment, and aquaculture production is largely Relying on natural conditions directly affects the effective use of resources and the improvement of benefits. The mechanization and automation of aquaculture are low, and it is difficult to meet the needs of industrialization and standardization of aquaculture. The main problem of emerging industrialized running water fish farming is the treatment of circulating water. It is more difficult, because most fish diseases are transmitted through water flow. In the process of water circulation, if the circulating water is not treated cleanly and the water quality is poor, it is easy to transmit the disease to other fish, resulting in the death of fish in groups. Affect breeding efficiency. To this end, the present invention proposes a combination of traditional pond fish culture and flowing water fish culture technology, scientific layout of paddy fields, river ditches, pond fish culture and water culture space and functions, comprehensive use of new culture facilities and new technologies, to achieve A system and method for high-density ecological fish farming in circulating water for efficient ecological farming.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a combination of traditional pond fish culture and flowing water fish culture technology, scientific layout of paddy fields, river ditches, pond fish culture and water culture space and functions, comprehensive utilization of new breeding facilities and new technologies, to achieve high efficiency A system and method for high-density ecological fish farming in circulating water for ecological farming.

In order to achieve the above object, the technical scheme adopted in the present invention is: a system and method for circulating flowing water high-density ecological fish farming, the system comprises flowing water fish farming ponds, clean water ponds, tail water purification ponds, river ditches and paddy fields, and flowing water farming ponds. The fish pond is set in the center of the water purification pond, tail water purification pond, river ditch and rice field. The pond is connected, the tail water discharge port of the running water fish pond is connected with the tail water purification pond, and the river ditch and the rice field are connected between the purification pond and the tail water purification pond. There are aquatic plants. After the water in the clean water tank is drawn into the running water aquaculture pond for fish farming, the fish excrement in the running water aquaculture pond is slowly drawn into the center of the running water aquaculture pond under the action of the centrifugal force of the water flow, and the tail is separated. The water is purified by rice and aquatic plants and then used for fish farming in running water, and the sedimented fish excrement is collected and used as fertilizer;

The running water fish pond includes an octagonal pond, a water inlet system, a drainage system, an oxygenation system, and a fish excrement collection and separation system. The octagonal pond is built with a brick-concrete structure side by side. pool;

The water inlet system includes a water inlet ditch, a submersible pump, and a water inlet main pipe. The water inlet ditch is set on the side where the clean water pool enters the octagonal pool. The inlet ditch and the octagonal pool are built with a common pool wall. The outlet is connected to the water inlet main pipe. There are several water inlet branch pipes on the water inlet main pipe. The outlet of the water inlet branch pipe passes through the pool wall and enters the octagonal pool, and the outlet direction of all the water inlet branch pipes is the same. The water in the ditch is sent into the octagonal pool through the water inlet main pipe and the water inlet branch pipe; the bottom of the pool wall is also buried with a water inlet transverse pipe, the water inlet of the water inlet transverse pipe is connected with the water inlet ditch, and the water inlet transverse pipe passes through The pool wall extends into the octagonal pool and is connected to the water inlet standpipe. The outlet direction of the water inlet standpipe is consistent with the outlet direction of the water inlet branch pipe. A vortex flow in one direction is formed in the octagonal pond, and the fish excrement gathers above the sewage collecting pond in the middle of the octagonal pond under the action of the centrifugal force of the water flow, and then the solids settle to the bottom of the sewage collecting pond, and then are extracted out of the pond to make organic fertilizer;

The drainage system includes a horizontal drainage pipe and a vertical drainage pipe. The horizontal drainage pipe is buried at the bottom of the octagonal pool. The inlet of the horizontal drainage pipe is connected to the sewage collection tank, and the outlet of the horizontal drainage pipe extends to the tail water purification tank outside the octagonal pool. It is connected with the drainage vertical pipe, and the drainage vertical pipe uses the water level difference between the octagonal pool and the tail water purification tank to press out the tail water;

The oxygenation system includes a blower, and the outlet of the blower is connected to an air delivery pipe, and the air delivery pipe is connected to the microporous oxygenation pipe at the bottom of the pool through the bronchus;

The fish excrement collection and separation system includes a sewage storage tank, a sewage horizontal pipe and a sewage vertical pipe. The sewage storage tank is set in the outer corner of the octagonal tank, and the sewage horizontal pipe is buried at the bottom of the octagonal tank. The outlet extends to the sewage storage tank outside the octagonal tank and then connects to the sewage vertical pipe. The sewage vertical pipe uses the water level difference between the octagonal tank and the sewage storage tank to press the collected solid feces into the sewage storage tank through the sewage vertical pipe. A sewage pump is provided, and an overflow port is arranged on the top of the side wall of the sewage storage tank. After the solid fish excrement is deposited in the sewage storage tank, the upper clean water flows out from the overflow port, and the sediment is pumped into the vegetable field through the sewage pump, which is used as vegetable cultivation. organic fertilizer;

Further, the construction depth of the octagonal pond is 2.3-2.5 meters, the depth of the inlet ditch is 2.3-2.5 meters, the width is 0.6-1.0 meters, and the length is consistent with the total length of the octagonal pond.

Further, the sewage collection tank is constructed in a funnel shape with a depth of 2-2.5×2-2.5 meters and a depth of 1.5 meters.

Further, the depth of the paddy field is less than that of the river ditch.

Further, the density of aquatic plants planted in the tail water purification pond and the river ditch is higher than that of the water purification pond. The rice is planted in the rice field in separate rows, and the planting row is in the same direction as the water flow.

Further, the position where the sewage transverse pipe is buried is lower than the position of the drainage transverse pipe.

Further, fishing nets are arranged at the inlets of the horizontal drainage pipes and the horizontal sewage pipes; fishing nets are arranged at the borders of the tail water purification pond with the paddy fields and the ditch, as tail water enters the waterways of the paddy fields and the ditch.

A method for high-density ecological fish farming in circulating water, comprising the following farming techniques:

(1) Feeding of fry: The octagonal pond implements a monoculture system, that is, one type of fish is raised in one octagonal pond, and crucian carp, carp and grass carp are placed in each octagonal pond respectively. -200 golden crucian carp of -200, 100 first-year carp with tail weight of 100-400g for carp per cubic water body, and 80 grass carp for grass carp with tail weight of 100-500g per cubic water body;

(2) Feeding management: The full-price compound feed is fed throughout the whole process. According to factors such as dissolved oxygen in the water, water temperature, and fish growth rate, the amount of feed will be adjusted in time. 2 to 3% of the fish body weight is counted and gradually increased to 5 to 7% with the growth of the fish. It is fed every 2 hours during the day; the amount of feed is adjusted every 10 days to ensure the growth of the fish;

(3) Timely oxygenation: high-pressure blower and microporous oxygenation tube are used as oxygenation equipment. According to the diurnal variation of dissolved oxygen in water, when the dissolved oxygen drops to 3 mg/L in the early morning or on cloudy and rainy days, the bottom microporous oxygenation technology is adopted. brake oxygenation;

(4) Comprehensive prevention and control of fish diseases: in the breeding process, garlic, three yellow powder and gall seeds are used to make medicinal bait for oral administration to prevent and treat fish enteritis and bacterial hemorrhage; salt, quicklime, neem and pine are used for fish body treatment Soaking or splashing the whole pool can kill insects and sterilize, and play the role of preventing and treating fish diseases;

(5) Water purification treatment:

①Water flow rate: use submersible pump to lift water, artificially create flow rate, and provide water source for octagonal pool. dead-end exchange;

②Ecological fish farming with circulating water in paddy fields: During the period of high water level from May to September, the river ditch and the water body of the paddy field are connected together, and the tail water discharged from the octagonal pond enters the paddy field, and absorbs ammonia nitrogen, nitrite and phosphate in the tail water through the rice. After the water quality is purified by nutrient-rich substances, it enters the purification pool and is used for running water for fish farming. The water for fish farming is mainly circulated in the paddy field;

③ Ecological fish farming with circulating water in the ditch: From the beginning of rice harvesting in October to April of the following year, when the water level of the ditch is at a low level, the water for fish farming circulates in the ditch. Aquatic plants such as Elodea absorb nutrient-rich substances such as ammonia nitrogen, phosphate, and nitrite. After the water quality is purified, it enters the purification pool and is then used for fish farming in the octagonal pond, and the cycle is repeated;

④ Collection and separation of fish excrement: The fish excrement is mainly feces and urine. Under the action of the centrifugal force of the water flow, the solid feces are slowly drawn into the center of the Eight-Yong Pond and settle into the sewage collection tank at the bottom of the pond. Dissolved feces and The urine is discharged into the tail water purification tank through the horizontal drainage pipe and the vertical drainage pipe, and the solid feces collected at the bottom of the sewage collection tank are pressed into the sewage storage tank outside the octagonal tank through the horizontal sewage discharge pipe and the sewage vertical pipe. After sedimentation in the sewage storage tank, clean water is discharged from the overflow port, and the sedimented fish excrement is pumped into the vegetable field through the sewage pump to be used as organic fertilizer for vegetable cultivation.

The beneficial effects of the present invention are:

(1) Implement the new technology of ecological fish farming with circulating water in paddy fields. On the one hand, fish excrement can be collected and extracted to provide organic fertilizer for the cultivation of green vegetables, turning waste into treasure; Ammonia nitrogen, phosphate, nitrite and other nutrient-rich substances are absorbed by the rice, which purifies the water quality, reducing the use of chemical fertilizers by 25% and pesticide use by 50% per mu of rice field. The biological purification of fish-farming tail water, the recycling of water bodies, and the absence of secondary pollution have played a positive role in protecting the ecological environment.

(2) Closed high-density fish farming greatly reduces the management scope and fishing space, effectively reduces labor and labor intensity, labor employment can be reduced by 60%, labor intensity can be reduced by 70%, and the use of fishery drugs is significantly reduced, effectively guaranteeing The water environment and the quality of aquatic products are safe. Flow aquaculture can significantly increase the unsaturated fatty acid content of fish meat and change the structural characteristics of fish meat.

(3) This aquaculture technology has the advantages of increasing production, improving quality, protecting water and land resources, saving energy, and reducing emissions. It is of great significance to create a new model of modern aquaculture, develop a comprehensive planting and breeding model of "one field for two purposes, one water and two harvests" and large-scale water surface proliferation.

Description of drawings

Fig. 1 is the floor plan of the present invention;

Figure 2 is a front view of a running water fish pond;

Fig. 3 is A-A sectional view in Fig. 2;

Fig. 4 is B-B sectional view in Fig. 3;

In the picture: 1- river ditch, 2- paddy field, 3- dam, 4- running water fish pond, 41- sewage storage tank, 42- octagonal pond, 43- water inlet ditch, 44- water inlet branch pipe, 45- sewage collection tank , 47-water inlet pipe, 48-submersible pump, 49-air pipe, 410-bronchial, 411-microporous oxygenation pipe, 412-overflow port, 413-sewage pump, 414-sewage standpipe, 415-sewage horizontal Pipe, 416-drainage horizontal pipe, 417-drainage vertical pipe, 418-water inlet horizontal pipe, 419-water inlet vertical pipe, 5-tail water purification tank, 6-water purification tank, 7-fish net.

Detailed ways

The present invention will be further described below with reference to the examples, which include but do not limit the protection scope of the present invention.

Example

1. Construction of running water fish farming project

(1), the construction site

The construction site is located at 500 meters from the Zhonghe River in Yahu Village, Yahu Neighborhood Committee, Sanbao Street, Qilin District, Qujing City, Yunnan Province, Qujing Bazi Center, 1 km away from National Highway 326, 10 km away from the central city of Qilin, with convenient transportation. 1 About 40 acres are connected together.

(2), the construction content

In the 240-mu contiguous paddy field and river ditch, three octagonal pools 42 were built, with a total area of 330 square meters and a total volume of 600 m ³ . Submersible pumps 48, water inlet system, drainage system, oxygenation system, and fish excrement collection and separation system were installed as a complete set. The running water fish pond 4; rice paddy 2 is planted in the paddy field 2, and water plants are planted in the river ditch 1, which is used as a purification area for the tail water of fish farming. The tail water discharged from the running water fish pond 4 passes through the paddy field and the water purification area of the river ditch 1. After the rice and aquatic plants absorb ammonia nitrogen to purify the water quality, they are reused for fish breeding in the running water pond through the water lifting facility, so as to realize the recycling of water, the collection and extraction of fish excrement, Circulating water ecological fish farming model for biological purification of water quality.

1. Construction of running water fish pond 4

The running water fish pond 4 is composed of an octagonal pond 42, a water inlet system, a drainage system, an oxygenation system, and a fish excrement collection and separation system. The water inlet side of the flowing water tank is the purification tank 6 , and the tail water discharge side is the tail water purification tank 5 .

(1) Pool construction. Construct 3 octagonal brick-concrete structure cement pools side by side, the bottom of the pool is funnel-shaped, the side length is 11m×11m square cut off the four corners, the pool depth is 2.3-2.5m, the water depth is 2m, the water storage is ^220m3 , and the area of each pool is 110㎡ , a total of 330 square meters.

(2) Install the drainage system. Install 2 (1 spare) 5.5kw submersible pumps 48 to lift water, build 43 inlet ditches with a length of 33.8 meters, a width of 0.8 meters and a depth of 2.5 meters, and install 25 pieces of PVC with a diameter of 75mm in each pool at the center of the ridge. The pipe is the water inlet standpipe 419; three PVC pipes with a diameter of 250mm are installed at the bottom of the pool as drainage pipes, with a length of 5m, extending to the outside of the pool. Install the standpipes of the same specification to maintain the water level in the pool to form an intake and drainage system.

(3) Install an oxygenation system. Install 2 sets (1 spare) 1.5kw high pressure blower as aeration equipment, and install air pipe 49, bronchi 410, and microporous aeration tube 411 at the bottom of the pool to form an oxygenation system.

(4) Set up a fish excrement collection and separation system. At the central drain at the bottom of the pool, a funnel-shaped sewage collection tank 45 with a side length of 2m x 2m x depth of 1.5m is built, which is connected to the sewage tank 41 through a pipeline, and a sewage pump 413 is used to extract fish excrement.

2. Ecological purification area and waterway settings

(1) Hegou Aquatic Plant Ecological Purification Area

The water surface of Hegou 1 is 40 mu, which is divided into 4 sections in a "U"-shaped layout. Aquatic plants are planted in the river ditch 1 (abbreviated as external water) outside the running water fish pond 4 (abbreviated as internal water), and the planting area accounts for 30-50% of the external water area as a biological purification area for fish rearing water. Such as planting water bamboo, elegans, water bitter grass and so on.

(2) Rice paddy ecological purification area

The paddy field 2 covers an area of 240 mu. At the junction of the tail water purification tank 5 and the paddy field 2, a fishing net 7 facility is built to enter the waterway of the paddy field 2 as tail water. Rice is planted in paddy field 2 as a biological purification area for the rear water of aquaculture.

2. Stocking of fingerlings

1. Species selection. Grass carp and crucian carp are the breeders bred by the farmer, and the specifications are uneven. For the insufficient part, select the fish fingerlings raised by farmers in the village with a short transportation distance in the surrounding area.

2. Stocking of fingerlings

(1) Preparation before stocking. Before the fingerlings are stocked, the first is to soak and change the water in the pool one week before stocking; the second is to test the water quality of the pool and the water quality in the purification area; the third is to adjust the flow rate.

(2) Stocking of fingerlings. A total of 4806kg of grass carp was placed in No. 1 running pool, with a total of 14,300 tails, with an average tail weight of 336g; a total of 2,408kg of golden crucian carp was placed in No. 2 running pool, with a total of 43,000 tails and an average tail weight of 56g; a total of 2,755kg of golden crucian carp was placed in No. 3 running pool, with a total of 56g. 62,600 tails, with an average tail weight of 44g.

After the fingerlings are stocked, turn off the water pump, turn on the bottom micropores to increase oxygen, and soak and disinfect with chlorine dioxide with a concentration of 0.76ppm for 1 hour.

3. Daily management

1. Feeding management

Monoculture is implemented in the running pond. One type of fish is raised in one running pond. The full-price compound feed is fed throughout the process, mainly Qujing Daxing feed, with a protein content of 30-32%, depending on factors such as dissolved oxygen in the water, water temperature, and fish growth rate. , timely adjust the amount of feed feeding. Under normal circumstances, in the first few days when the fingerlings are placed in the pond, the daily feeding is calculated at 2-3% of the fish's body weight, and gradually increases to 5-7% as the fish grows. Feed once every hour; adjust the feeding amount every 10 days to ensure the growth needs of the fish.

2. Water quality monitoring and water flow regulation and management

(1) Monitor the water quality changes of the inlet pool and 3 flowing pools 3-5 times a week, mainly monitor the dissolved oxygen, ammonia nitrogen, PH, nitrite nitrogen and water temperature in the water, and take measures to adjust the water quality in time when problems are found.

(2) Water velocity. Use the submersible pump 48 to lift water, artificially create a flow rate, and provide a water source for the flowing pool. The flow rate of the water body in the flowing pool is controlled at 2-5cm/sec, the water body exchange volume is 1-6 times/hour, and the bottom drainage is used for drainage, and the water body has no dead angle exchange.

(3) Water purification treatment. The running water tank has the function of collecting sewage. After the fish excrement is first deposited in the sewage collecting tank 45, the solid excrement is extracted by the sewage pump 413. The tail water then passes through the tail water purification area, and absorbs dissolved ammonia nitrogen, Nitrite, phosphate, absorb nutrients in the water, and further purify the water.

(4) Timely oxygenation. Use high-pressure blower and microporous nano-aeration tube as oxygen-enhancing equipment. According to the diurnal variation of dissolved oxygen in water, when the dissolved oxygen drops to 3㎎/L in the early morning or on cloudy and rainy days, the bottom microporous oxygenation technology is used to brake and increase oxygenation.

3. Fish disease prevention and disease management

(1) Adhering to the fish disease prevention and control policy of "prevention first, supplemented by treatment", and adopting a comprehensive prevention and control method of "internal and external use, and water quality improvement" to ensure that farmed fish are less sick or not sick is the key to successful farming. The use of Chinese herbal medicine to control fish diseases, the use of aquatic plants and microorganisms (Bacillus, photosynthetic bacteria, etc.) to improve water quality, and the implementation of ecological fish farming are effective ways to improve the quality of aquatic products.

(2) From June to October, use Chinese herbal medicines such as allicin, three yellow powder (rhubarb, yellow lotus, scutellaria baicalensis), Gandan Yikang, Xuexuekang and vitamin C to make bait every month, feeding for 3-5 days, can prevent, Treatment of fish enteritis, bacterial hemorrhage and so on.

(3) Sprinkling chlorine dioxide in the whole pool every 15-20 days can sterilize and adjust water, and play the role of preventing and treating fish diseases. Regular microscopic inspections. Insecticides such as Zhihuanqing or insecticide special Chinese herbal medicine.

4. Suction and discharge management

Fish excrement is mainly feces and urine. Under the action of the centrifugal force of the water flow, the solid feces are slowly drawn into the center of the pond and settle into the sewage collection tank 45 at the bottom of the pond. Dissolved feces and urine are discharged into the tail water tank through the drain pipe. Using the water level drop, the collected solid manure is pressed into the sewage storage tank 41 outside the flow tank through the pipeline. Regularly use sewage pump 413 to pump fish excrement into vegetable fields as organic fertilizer for vegetables.

5. Emergency management

Insist on patrolling the pond in the morning, noon and evening every day to observe the activity of fish and the operation of equipment.

6. Production file management

Do a good job of daily breeding production records. Mainly include: species, specifications, time and quantity of fingerling stocking; feed source and feeding situation; disease prevention and treatment: main symptoms, drug name, time and dosage, etc.; fish production measurement and sales; match, etc.

4. Benefit Analysis

No. 1 running pool: total weight of grass carp 12227kg, average size 950g/tail; No. 2 running pool: total weight of crucian carp 10213kg, average size 240g/tail; No. 3 running pool: total weight of crucian carp 12489kg, average size 210g/tail; outside water (Hegou): The total weight of silver carp and bighead carp is 10860kg, the average size is 750g/tail, and the total fish production is 45789kg.

1. Economic benefits

(1), fish farming benefits:

Output value: 45789kg×11.81 yuan/kg=540957 yuan

Cost: 148,588 yuan for fingerlings + 164,634 yuan for feed + 6,000 yuan for labor + 10,500 yuan for fish medicine + 20,906 yuan for water and electricity = 350,628 yuan

Profit: output value of 540,957 yuan - cost of 350,628 yuan = 190,329 yuan

(2), paddy field efficiency

Increased rice yield: (745.6-699.5) kg/mu × 3.5 yuan/kg × 200 mu = 32,270 yuan

Fertilizer saving (calculated by urea): 2.6 tons × 2,250 yuan/ton = 5,850 yuan

Pesticide saving: 200 mu × 20 yuan/mu = 4,000 yuan

Energy saving and efficiency increase: 32270+5850+4000=42120 yuan

The total net income of fish farming and paddy field efficiency increase is 232,449 yuan, the breeding cycle is 150 days, 240 mu of paddy fields and rivers, and the average net income per mu of rice fields and rivers is 969 yuan.

(3) Comparative analysis

Benefit comparison between ecological fish farming in paddy field and river ditch circulating water and river ditch aquaculture: the aquaculture output after the transformation is 45789kg, and the output value is 540957 yuan. In the past, the output of 40 acres of river ditch aquaculture was 25,000kg, and the output value was 325,000 yuan. In comparison, the ecological fish culture in paddy and river ditch circulating water increased the output by 20,789kg, and increased the income by 145,369 yuan, with an average increase of 520kg per mu and an increase of 3,634 yuan per mu.

2. Social benefits

240 acres of paddy fields, rivers and gully circulating water ecological fish farming, the breeding cycle is 150 days, a total of 45.79 tons of ecological aquatic products and 149,100 kilograms of high-quality rice are produced, providing healthy green ecological food for the society. The implementation of ecological fish farming with circulating water in paddy fields has increased the yield of aquatic products from the original 50kg/mu to 191kg/mu, increasing the annual output of aquatic products by 33.84 tons, and the paddy output by 6.59% and 9,220 kg. Under the new situation that the aquaculture area has been greatly reduced, a new way has been opened up for the production of green ecological aquatic products and the increase in the production of aquatic products.

3. Ecological benefits

Implementing the new technology of ecological fish farming with circulating water in paddy field, on the one hand, it can collect and extract fish excrement to provide organic fertilizer for the cultivation of green vegetables, turning waste into treasure; , phosphate, nitrite and other nutrient-rich substances are absorbed by the rice, purifying the water quality, reducing the use of chemical fertilizers by 25% and the use of pesticides by 50% per mu of rice fields. The biological purification of fish-farming tail water, the recycling of water bodies, and the absence of secondary pollution have played a positive role in protecting the ecological environment.

Claims (8)

1. A system and a method for high-density ecological fish culture by circulating water are characterized in that: the system comprises a flowing water fish pond (4), a clean water pond (6), a tail water purification pond (5), a river ditch (1) and a rice field (2), wherein the flowing water fish pond (4) is arranged at the central positions of the clean water pond (6), the tail water purification pond (5), the river ditch (1) and the rice field (2), the clean water pond (6), the tail water purification pond (5), the river ditch (1) and the rice field (2) are separated by a dam (3), a water inlet of the flowing water fish pond (4) is communicated with the clean water pond (6), a tail water outlet of the flowing water fish pond (4) is communicated with the tail water purification pond (5), the clean water pond (6) and the river ditch (1) are all planted with plants, water in the clean water pond (6) is extracted to enter the flowing water fish pond (4) for fish culture, the fish body excrement in the flowing water fish pond (4) is slowly rolled into the center of the flowing water fish pond (4) under the action of the water flow rotating centrifugal force for sedimentation and separation, tail water is purified by rice and aquatic plants and then used for flowing water fish culture, and the precipitated fish body excrement is collected and used as fertilizer;

the flowing water fish pond (4) comprises an octagonal pond (42), a water inlet system, a drainage system, an oxygenation system and a fish body excrement collecting and separating system, wherein the octagonal pond (42) is built by adopting a brick-concrete structure at least more than one opening side by side, and a funnel-shaped sewage collecting pond (45) is arranged in the middle of the bottom of each pond;

the water inlet system comprises a water inlet ditch (43), a submersible pump (48), a water inlet header pipe (47), a water inlet transverse pipe (418), a water inlet vertical pipe (419) and short pipes (420), wherein the water inlet ditch (43) is arranged on one side of the purified water tank (6) entering the octagonal tank (42), the water inlet ditch (43) and the octagonal tank (42) are built with a common tank wall, an inlet of the submersible pump (48) is connected with the water inlet ditch (43), an outlet of the submersible pump is connected with the water inlet header pipe (47), a plurality of water inlet branch pipes (44) are arranged on the water inlet header pipe (47), outlets of the water inlet branch pipes (44) penetrate through the tank wall to enter the octagonal tank (42), the outlet directions of all the water inlet branch pipes (44) are consistent, and the submersible pump (48) pumps water in the water inlet ditch (43) and sends the water inlet branch pipes (44) into the octagonal tank (42); the bottom of the pond wall is also embedded with a transverse water inlet pipe (418), a water inlet of the transverse water inlet pipe (418) is communicated with a water inlet ditch (43), the transverse water inlet pipe (418) penetrates out of the pond wall and extends into the octagonal pond (42) to be connected with a vertical water inlet pipe (419), the outlet direction of the vertical water inlet pipe (419) is consistent with the outlet direction of the branch water inlet pipe (44), water in a water flow stirring pond entering the octagonal pond (42) from the vertical water inlet pipe (419) and the branch water inlet pipe (44) forms a vortex flow in one direction in the octagonal pond (42), fish excrement is converged above a sewage collection pond (45) in the middle of the octagonal pond (42) under the action of the rotating centrifugal force of the water flow, then solid is precipitated at the bottom of the sewage collection pond (45), and then is pumped out of the pond to serve as organic;

the drainage system comprises a transverse drainage pipe (416) and a vertical drainage pipe (417), the transverse drainage pipe (416) is embedded at the bottom of the octagonal pool (42), an inlet of the transverse drainage pipe (416) is communicated with the sewage collecting pool (45), an outlet of the transverse drainage pipe (416) extends to the tail water purification pool (5) outside the octagonal pool (42) and then is connected with the vertical drainage pipe (417), and the vertical drainage pipe (417) utilizes the water level difference between the octagonal pool (42) and the tail water purification pool (5) to press out tail water;

the oxygen increasing system comprises a blower, the outlet of the blower is connected with an air conveying pipe (49), and the air conveying pipe (49) is connected with a micropore oxygen increasing pipe (411) at the bottom of the pool through a branch air pipe (410);

the fish body excrement collecting and separating system comprises an excrement storage pool (41), a transverse sewage discharging pipe (415) and a vertical sewage discharging pipe (414), wherein the excrement storage pool (41) is arranged at one corner of the outer side of an octagonal pool (42), the transverse sewage discharging pipe (415) is buried at the bottom of the octagonal pool (42), an inlet of the transverse sewage discharging pipe (415) is communicated with the bottom of a sewage collecting pool (45), an outlet of the transverse sewage discharging pipe extends to the position outside the octagonal pool (42) of the excrement storage pool (41) and then is connected with the vertical sewage discharging pipe (414), the vertical sewage discharging pipe (414) presses collected solid excrement into the excrement storage pool (41) through the vertical sewage discharging pipe (414) by utilizing the water level difference between the octagonal pool (42) and the sewage storage pool (41), a sewage pump (413) is arranged in the sewage storage pool (41), an overflow port (412) is arranged at the top of the side wall of the excrement storage pool (41), upper clear water flows out from the overflow port (412), and sediments are pumped into a vegetable field through, can be used as organic fertilizer for vegetable cultivation.

2. The system for ecological fish culture with circulating water and high density as claimed in claim 1, wherein: the construction depth of the octagonal pool (42) is 2.3-2.5 meters, the depth of the water inlet ditch (43) is 2.3-2.5 meters, the width is 0.6-1.0 meter, and the length is consistent with the total length of the octagonal pool (42).

3. The system for ecological fish culture with circulating water and high density as claimed in claim 1, wherein: the sewage collecting pool (45) is constructed into a funnel shape with the depth of 1.5 meters and the depth of 2-2.5 multiplied by 2-2.5 meters.

4. The system for ecological fish culture with circulating water and high density as claimed in claim 1, wherein: the depth of the rice field (2) is less than that of the river channel (1).

5. The system for ecological fish culture with circulating water and high density as claimed in claim 1, wherein: the density of aquatic plants planted in the tail water purification pool (5) and the river channel (1) is greater than that of aquatic plants planted in the water purification pool (6), and rice is planted in the rice field (2) in a moisture-retention and row-planting manner, and the planting direction of the planting row is consistent with the water flow direction.

6. The system for ecological fish culture with circulating water and high density as claimed in claim 1, wherein: the position where the horizontal drainage pipe (415) is buried is lower than that of the horizontal drainage pipe (416).

7. The system for ecological fish culture with circulating water and high density as claimed in claim 1, wherein: a fish blocking net (7) is arranged at the inlets of the horizontal drainage pipe (416) and the horizontal drainage pipe (415); a fish blocking net (7) is arranged at the connection part of the tail water purification pool (5) and the rice field (2) and the river channel (1).

8. The method for ecologically culturing fish in high density by using circulating water as claimed in any one of claims 1 to 7, wherein: comprises the following culture techniques:

(1) and (3) putting the fry: the octagonal pool (42) is subjected to a single breeding system, namely one octagonal pool (42) is used for breeding one kind of fish, crucian, carp and grass carp are respectively put in each octagonal pool (42), and the putting amount is as follows: the crucian carp is prepared by putting 200 tails of golden crucian carps with the tail weight of 100-;

(2) feeding management: feeding the cured complete compound feed in the whole process, adjusting the feed feeding amount in time according to factors such as dissolved oxygen in water, water temperature and fish body growth speed, and under normal conditions, feeding the fish seeds for the first few days in a pond according to 2-3% of the weight of the fish bodies, gradually increasing the feeding amount to 5-7% along with the growth of the fish, and feeding the fish once every 2 hours in the day; adjusting the feed feeding amount for 1 time every 10 days to ensure the growth requirement of the fish body;

(3) timely oxygenation: a high-pressure blower and a micropore oxygenation pipe (411) are used as oxygenation equipment, and according to the day and night change rule of dissolved oxygen in water, when the dissolved oxygen is reduced to 3mg/L in the morning or in rainy days, the bottom micropore oxygenation technology is adopted to brake for oxygenation;

(4) fish disease comprehensive prevention and treatment: in the culture process, garlic, three-yellow powder and gallnut are used for preparing a medicinal bait for oral administration, so as to prevent and treat enteritis and bacterial hemorrhagic disease of fish bodies; the fish bodies are soaked or splashed in a whole pool by utilizing the salt, the quicklime, the chinaberry and the pine needles, so that the fish killing and sterilizing effects can be achieved, and the fish diseases can be prevented and treated;

(5) water purification treatment:

flow velocity of water: the submersible pump (48) is adopted to lift water, the flow rate is artificially manufactured, a water source is provided for the octagonal pool (42), the flow rate of water in the octagonal pool (42) is controlled to be 2-5 cm/s, the exchange quantity of the water is 1-6 times/hour, the water is drained in a bottom drainage mode, and the water has no dead angle exchange;

secondly, ecological fish culture by using circulating water in the rice field: in a high water level period of 5-9 months, a river ditch (1) and a paddy field (2) are connected into a whole, fish culture tail water discharged from an octagonal pond (42) enters the paddy field (2), rich nutrient substances such as ammonia nitrogen, nitrite and phosphate in the tail water are absorbed by paddy, water quality is purified and then enters a water purifying pond (6) to be used for culturing fish in running water, and water for culturing fish mainly circulates in the paddy field (2);

③ ecological fish culture by using river ditch circulating water: during the period from the beginning of harvesting rice in 10 months to the next 4 months, the water level of the river channel (1) is in a low water level period, water for fish culture circulates in the river channel (1), tail water for fish culture discharged from the aniseed pool (42) enters the river channel (1), aquatic plants such as cane shoots and elodea nutraceutica absorb rich nutrient substances such as ammonia nitrogen, phosphate and nitrite, water quality is purified, then the water enters the water purifying pool (6), and the water is used for fish culture in the aniseed pool (42) and circulates;

collecting and separating fish excrement: the fish excrement is mainly excrement and urine, solid excrement is under the effect of the rotatory centrifugal force of rivers, slowly be drawn into eight with pond (42) pond center, deposit to bottom of the pool collection dirty pond (45), dissolubility excrement and urine are passed through in drainage violently pipe (416) and drainage standpipe (417) discharge tail water purification tank (5), collect the solid excrement and urine of collection dirty pond (45) bottom and utilize the water head, impress in octagonal pond (42) outer storage dirty pond (41) through blowdown violently pipe (415) and blowdown standpipe (414), excrement and urine deposits the back in storage dirty pond (41), the clear water is discharged from overflow mouth (412), fish excrement and urine that deposits down passes through sewage pump (413) suction to the vegetable field, as vegetable cultivation fertilizer.

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