1 Factory-based fish farming
Factory-based fish farming refers to the use of disciplines such as architecture, electromechanical, chemistry, and automatic control to control water quality, water temperature, and water flow in fish production. Semi-automatic or fully automated management of feeding, sewage discharge, etc. is always maintained to maintain the best physiological and ecological environment of fish, thereby achieving healthy and rapid growth and maximizing fish production and quality per unit water body without causing pollution inside and outside the breeding system. An efficient farming method.
Factory fish farming is the most advanced method of fish farming today. It has many advantages such as small area, high yield, little impact on the natural environment, continuous production throughout the year, high economic benefits, and automated operation and management. , and the closed circulating flowing water fish farming is not easy to cause pollution to the marine environment and consumes less water. It is an environmentally friendly green farming method. Today's marine aquaculture is moving towards sustainable development with marine environmental protection as the core. Therefore, factory-based fish farming is one of the best farming methods that conforms to the development trend of marine aquaculture. Factory-based fish farming is a high-input, high-output, high-risk industry with large investment, strict management, and strong technology. It is suitable for production by large and medium-sized enterprises with strong capital, strong technical force, and rich management experience.
Our country’s factory farming started late, with low levels of technical equipment and automatic control. Although there has been some development, it is still relatively rudimentary high-density indoor farming, with only the addition of aeration and running water, which is basically It is an open-type, flowing water culture. The cultured species include abalone, sea bream, flounder, American redfish, etc. However, the nursery of most species is basically cultivated in a factory-style way, forming a supporting system.
1. Types of factory-based fish farming
There are various forms of factory-based fish farming on land, including three main types: ordinary flowing water fish farming, warm flowing water fish farming and circulating flowing water fish farming. .
1. Ordinary flowing water fish farming
After simple treatment (such as sand filtration) using natural seawater, it does not need to be heated and flows directly into the fish pond. The used water is directly Fish farming methods that discharge into the sea. This method has simple equipment and low investment, and is suitable for short-term or low-density farming in the southern temperate areas. It is the lowest stage of factory-based fish farming. Suitable for the breeding of sea bream, perch, grouper, flounder, pufferfish and other seawater carnivorous fish.
2. Warm water fish farming
An industrial fish farming method first developed in Japan in the early 1960s. It uses natural hot water (such as warm water wells, hot spring water ), warm drainage water from power plants and nuclear power plants or artificially heated seawater is used as a water source for fish farming. It enters the fish pond after simple treatment (such as temperature adjustment), and the used water is no longer recycled. Since geothermal water and hot spring resources are limited, this breeding method is mainly used in the comprehensive utilization of warm water from factories. At present, fish farming in warm flowing water is relatively popular in Japan, Russia, the United States, Germany, Denmark, France and other countries. Our country has developed rapidly in recent years. For example, there are dozens of warm-flow fish farming plants in Jiaodong area of ??Shandong Province, with a fish farming area of ??about 200,000 m2 and an annual output of more than 1,000t of various high-grade sea fish. The cultured species include flounder, rock flounder, and flounder. Plaice, black gill, six-line fish, sea bream, etc. There are three main methods of temperature regulation in these fish farms: ① Coal-fired boiler heating + natural sea water type, such as Gushan Fish Farm in Weihai, Shandong Province, Rongcheng Xunshan Fish Farm, etc.; ② Warm drainage from power plants + natural sea water type, such as Qingdao Huangdao Power Plant Fish Farm, Weihai Huaneng Power Plant Fish Farm, etc.; ③ Warm water well + natural seawater type, such as Rongcheng Qiujia Fishery Company Fish Farm and Shandong Province Penglai Fish Breeding Experimental Plant, etc. This method of fish farming has simple technology and equipment, low yield, and large water consumption. It is the primary stage of industrialized fish farming.
3. Circulating flowing water fish farming
It is also called closed circulating flowing water fish farming. Its main feature is that it consumes less water. The water discharged from the fish pond needs to be recycled. After aeration, After sedimentation, filtration, and disinfection, temperature adjustment, oxygenation, and appropriate amount (1 to 10%) of fresh water (the part lost or evaporated in the system circulation) are added according to the physiological needs of different cultured objects at different growth stages, and then restarted. Enter it into a fish pond and use it repeatedly. This system also needs to be equipped with water quality monitoring, flow rate control, automatic feeding, sewage discharge and other devices, and is automatically monitored by the central control room. It is the most integrated, highest level of automated management in current fish farming production, and has no internal or external environment of the system. The polluting high-tech fish farming system is the highest level of industrial fish farming and will surely become the mainstream and development direction of factory fish farming. At present, the region with the highest technological level in the world is Europe, and some countries have been able to export complete sets of fish farming equipment.
The unit yield of circulating water fish farming has reached 100~300kg/m2.a, and the highest is 750~1500kg/m2.a. Only 1~10% of water is supplemented, and the automatic water purification capability is very strong.
2. Factory Fish Farming Facilities
According to different marine culture objects and water quality requirements, the currently applied factory farming technology lines are different and involve a wide range of equipment. Each has its own characteristics. Generally speaking, the two factory-based fish farming methods, ordinary flowing water fish farming and warm flowing water fish farming, require less equipment. Ordinary flowing water fish farming is based on ordinary pond farming and adds sand filter to filter and extract seawater or well water, and the wastewater after farming is directly discharged into the sea. Warm flowing water fish farming adds temperature control equipment and warm drainage pre-treatment equipment, such as boilers, thermal insulation greenhouses, etc., on the basis of flowing water fish farming; it is also not complicated. Factory fish farming in the true sense is circulating flowing water fish farming, which requires a lot of equipment and advanced technology. We will focus on it below.
Author: jnjy_hym 2007-1-19 16:57 Reply to this statement
--------------------- -------------------------------------------------- --------
2 Factory fish farming
The seawater factory farming system mainly consists of the following systems: (1) fish pond system; (2) water quality Purification treatment system (3) automatic monitoring system, etc.; (4) automatic feeding system and other auxiliary systems.
1. Fish pond system includes fish ponds, inlet and drainage pipes and fish blocking equipment. Fish ponds are generally located indoors, with concrete structures or fiberglass water tanks. The shapes are mostly polygonal, rectangular, or circular. The area generally does not exceed 50m2, and the depth of the pond is about 1m. The bottom is designed with a certain slope to facilitate drainage. The water inlet pipe of the water inlet and drainage system is a plastic pipe, and the diameter varies according to the water supply. The water inlet pipe opening is located at the upper part of the fish pond (30cm from the upper edge). The drainage pipe opening is located at the center of the bottom of the pool or on one side of the bottom. The discharge pipe is connected to the aeration tank. Or connected to the sedimentation tank. The fish-blocking device is a metal mesh or grid foil installed at the drainage outlet. The hole diameter should be suitable for sewage discharge but not for fish to escape.
2. Water purification and treatment system Water purification and treatment is the key to the entire circulating water factory-based fish farming. The entire water quality treatment system includes the following links: 1. Solid waste removal; 2. Water-soluble harmful substances removal; 3. Sterilization and disinfection; 4. Oxygenation; 5. Temperature regulation; 6. Water quality measurement and control.
(1) Removal of solid waste In traditional tidal flat breeding ponds, the thickness of the sedimentary silt layer after self-purification every year is as much as 10cm. The density of factory fish farming is relatively high, and the amount of solid waste produced It is even larger, including fish manure, residual bait and other debris (fibers, particles, flakes), the organic content accounts for about 80%, and is the main source of aquaculture water pollution. In the water circulation system of factory farming, it must first be It should be removed in time to reduce the load on subsequent process links and prevent clogging.
Filter bed filtration Using filter bed filtration is a more commonly used method. The flow of water from the upper layer to the lower layer is called forward filtration, and the flow of water from the lower layer to the upper layer is called reverse filtration. The filtration effects are similar, but forward filtration is prone to clogging, while reverse filtration is difficult to remove solid matter.
Screen filter Compared with sand filter, screen filter has advantages in terms of volume, installation and backwash operation.
The fixed screen filter is a quick-opening dirt remover. It is shaped like a barrel with a mesh basket inside. There is a screen in the basket. The water flows through the screen and solid objects larger than the mesh are trapped. After filtering and accumulation, the baskets are removed manually at regular intervals. The mesh size varies from 60 to 200 mesh/inch according to the needs of marine aquaculture. It is characterized by easy installation and simple operation. In seawater circulation treatment systems, it is often used to filter solids with particles larger than 0.5mm in front of the pump. The unit filtration capacity is 10~100m3/h.
The circular rotating screen of the rotary screen filter is partially immersed in the water, and the water flows through the inner surface of the rotating screen to filter out impurities. A sewage drain is installed on the inside of the screen above the water surface, and the corresponding part on the outside of the screen. Set up a nozzle group. During automatic backwashing, the high-pressure water from the nozzles will flush the solids filtered out of the screen into the sewage trough below and wrap them up for discharge. The mesh of seawater type is 80~150 mesh/inch, the backwash water pressure is 0.2~0.6MPa, the unit filtration capacity is 14~400m3/h, and the power consumption is less than 1.5KW/h. In addition, there are chain moving screens, vibrating screens, etc.
Rotary screen filtration has a better application effect in marine aquaculture plants. It is characterized by continuous operation and good anti-blocking performance.
Automatic cleaning filter is a new type of fully automatic filter that combines the operating characteristics of a fixed screen structure and the performance advantages of a rotating screen. The shell mechanism is shaped like a quick-opening dirt remover. A stainless steel brush driven by an 11KW motor is designed in the center. It rotates around the inner wall of the filter screen to brush off the filtered matter attached to the surface of the screen, and then is discharged controlled by the drain valve. If a suction scanner is used instead of a stainless steel brush, the suction port of the scanner can suck up particulate impurities during rotation and eliminate them. It is characterized by continuous flow during backwashing and very little sewage discharge. Cleaning and discharge can be carried out according to pressure difference or timing control, and the cleaning cycle adopts electronic monitoring with a computing chip. The filter material is divided into stainless steel 316 (pore diameter 0.2 ~ 3.5mm) and woven filter (pore diameter 0.025 ~ 0.5mm) types. It is suitable for filtration systems with large flow (Qmax=1000m3) and large filtering area (10000cm2). It is the most advanced screen filter in breeding factories at present.
Foam separator Foam separator can effectively remove suspended solutes in water and is one of the key technologies for treating filtered seawater. The principle is to introduce air into the water to be treated, so that the surface active substances in the water are absorbed by the tiny bubbles, and float to the water surface with the bubbles to form foam, and then separate the foam on the water surface to remove dissolved and suspended pollutants in the wastewater. purpose. Application tests have shown that the solid content of dirt collected in the foam separator can reach 39%. It is particularly effective for low-concentration aquaculture water bodies. It not only eliminates sources of ammonia nitrogen such as protein but also increases oxygen. The effect of injecting ozone is better.
(2) After using biofilm technology to remove water-soluble harmful substances and exclude solid phase matter, the water-soluble substances in the circulation system mainly exist in the form of "trinitrogen", ammonia nitrogen (NH3-N) It is very toxic. It can quickly enter the blood of fish through the gills and skin, interfere with the normal tricarboxylic acid cycle of the fish, change the osmotic pressure of the fish, reduce the ability of the fish to use oxygen in the water, and affect the growth of the fish; Nitrate nitrogen (NO-2-N) can quickly penetrate into the fish body, causing the ferrous hemoglobin that combines with oxygen in the blood to inactivate, turning it into iron hemoglobin, thereby losing its oxygen-carrying function, and in severe cases, life-threatening; Nitrate nitrogen (NO-3-N) is generally considered to be very toxic, but as nitrogen metabolism continues and the total amount of nitrogen accumulates, too high a concentration will also affect the growth of fish, causing fish body color to deteriorate and meat quality to decline. These water-soluble substances are generally treated with biofilm technology. The equipment mainly includes immersed biological filter tanks, trickling filters, water purifiers and plant purification devices.
Author: jnjy_hym 2007-1-19 16:57 Reply to this statement
--------------------- -------------------------------------------------- --------
3 Factory Fish Farming
The tank body of the immersed biological filter tank is rubber-lined carbon steel or wound fiberglass, and an air diffuser is arranged inside the tank (The ratio of ammonia nitrification to oxygen consumption is 1:4.57) and biological filler to form a biological package (the ability to process ammonia is 114~200g/m3·d). Biological fillers are carriers of nitrifying bacteria and are divided into hard and soft materials, both of which are required to be non-toxic. Hard fillers are polyethylene, polypropylene bio-balls or honeycomb fillers, or microporous ceramic rings and bio-stones. The soft filler is made of vinylon fiber with a diameter of 7 μm, which can spread freely in water, has a specific surface area of ??2000m2/m3, and has a strong ammonia nitrogen removal rate of 80%. The disadvantage is that it is easily interfered by other factors in the water and causes balling, which affects the use effect. In addition, ultra-fine active materials and immobilized microorganisms are also added to the additive carrier to enhance the processing capacity. Biological packages are generally arranged in unit groups. In order to increase the treatment effect, beneficial water purification bacteria, such as NO-2 and NO-3 nitrifying bacteria and NO-2 and NO-3 reductases, can be added.
The structure of the drip filter tank is similar to that of the submersed filter tank. The volume ratio of the two is 1:2. It receives the filtered water from the submerged filter tank in the form of dripping. It goes in and out from the top, and the water level is controlled, so that the filter material (biological filter ball, elastic filler, etc.) is in a moist state with air and water alternately attached, and the gaseous waste (N2, CO2, CO) in the water overflows during the trickling filter. In addition to the tank type structure, there is also a trickling filter form stacked by multiple plastic boxes (with leak holes at the bottom), which is economical, reasonable and practical.
Water purifiers include biological turntables, biological rotating balls and biological rotating cylinders. The principle is to use microbial adsorption to form a biofilm. By rotating alternately in the air and water, it not only increases oxygenation, but also absorbs and nitrates harmful ammonia nitrogen and nitrite. Some organic matter is directly synthesized into The organic matter in microorganisms is purified by water. This type of device has the functions of immersion filtration and trickle filtration.
The aquaponics cultivation device mainly connects cultivation trays, troughs, bowls, boards and substrates in series in the fish farming circulation system to carry out soilless cultivation of vegetables and flowers, and utilizes the absorption of nitrate by plant roots. Remove nitrate nitrogen by absorption. This is currently the most effective key technology to solve the nitrogen cycle in fully closed breeding systems. It provides a feasible way to achieve zero-emission and waste-free production and has good ecological effects. Plants adapted to seawater environments are some salt-tolerant species, or are gradually adapted from some freshwater plants to be salt-tolerant.
(3) Sterilization and disinfection In order to avoid the side effects caused by the introduction of chemical drugs, physical sterilization and disinfection are often used in seawater factory fish farming.
Ozone generator generates ozone based on the principle of discharge. Ozone is extremely unstable and will quickly reduce to oxygen. It has strong oxidizing ability and strong bactericidal effect. Ozone is heavier than oxygen and can increase dissolved oxygen in water and adjust the pH value of water. Especially when used in combination with ultraviolet light, it can greatly reduce BOD and COD values, reduce nitrite to a very low limit, and convert ammonia nitrogen into nitrate. Improve breeding water quality. The sterilization efficiency is better than that of chlorine and sodium hypochlorite. In the application of seawater factory farming, the dosage is determined according to the specific breeding objects and water quality conditions. Generally, the maintenance concentration for breeding (0.08~0.2) mg/L, and the therapeutic concentration (1~1.5) mg/L. The leakage problem of residual ozone can be solved through repeated circulation, activated carbon adsorption and heating methods.
Ultraviolet sterilizer is a cylindrical ultraviolet lamp designed in the water pipe. The ultraviolet lamp directly radiates ultraviolet light of 230-270nm wavelength to the surrounding flowing water, which can achieve the effect of sterilization and algae removal. The transparency of water quality has a great influence on the irradiation effect. The irradiation thickness is controlled within 20mm, the irradiation time is greater than 10s, and the irradiation dose is 1.0×104mV·s/cm2. At the same time, pay attention to prevent the refraction of ultraviolet rays.
(4) Oxygenation and temperature adjustment In the seawater factory farming system, fish ponds, foam separation, and biological filtration all require a large amount of oxygen (about 7.57kg of oxygen per ton of fish per day), generally more Roots blower and vortex inflator are used, among which the three-blade Roots blower has better stability and low noise effect. Due to its strong oxygenation efficiency, simple structure, and ease of use, the impeller-type aerator is widely used in water quality conditioning ponds and secondary ponds in fish farming factories. In recent years, there have also been methods of using pure oxygen, liquid oxygen and molecular sieve oxygen enrichment devices (purity reaching more than 90%) to increase dissolved oxygen in water bodies. Adopt high-efficiency gas-water mixing device and adopt jet, spiral, mesh diffusion and other gas-water mixing technologies to make the water gas molecules smaller and easier to mix, so that the dissolved oxygen in the water body can reach saturation and supersaturation, improve the utilization rate of oxygen, and at the same time have sterilization , anti-corrosion effect. This device can also be used for ozone gas-water mixing.
(5) In addition to boiler pipe heating (mainly using hot water boilers) and electric heating (rod, tube, line form), temperature regulation also uses equipment such as combined heat pump cold and hot water units. Regulate the temperature of water bodies. The water temperature is controlled by a computer, and the pool water temperature is controlled by controlling the indoor temperature. Since the water volume is small and the density of fish is high, temperature control is mainly about cooling rather than heating.
(6) Water quality measurement and control The overall functions and effects of the factory-based fish farming system depend on the monitoring and control of water quality. The use of modern automatic monitoring systems can monitor and regulate water quality throughout the entire process, and realize automatic monitoring, alarming and automatic start-up of related equipment regulation. In addition, the factory farming system also involves automatic monitoring systems and automatic feeding systems, involving the application of computer monitoring, water pumps, automatic feeding machines, underwater cleaners and other equipment.
Author: jnjy_hym 2007-1-19 16:57 Reply to this statement
--------------------- -------------------------------------------------- --------
4 Factory fish farming
3. Breeding technology
The main differences between factory fish farming and still water pond fish farming Yes: the pond area is small, the pond water continues to flow and exchange, the source of dissolved oxygen in the pond water relies on flowing water or mechanical oxygenation, there are few natural bait organisms, fish nutrition completely comes from artificial feeding, and fish excrement and other substances in the pond water follow the water flow. It is discharged in time, so the water quality is relatively fresh; the stocking objects are devouring fish, the species are relatively simple, and the density and yield are large.
1. Fish fingerlings
The fish suitable for factory farming are usually high-quality carnivorous species, such as eels, flounder, turbot, grouper, etc. The size of the seeds is generally 50-150g, so that they can reach the size of edible fish that year.
Density Whether the breeding density is reasonable also determines the benefits of the entire factory farming. Breeding density should be determined based on water source, water quality, infrastructure and technology, and management level. Ordinary flowing water fish farming is generally 50 to 200 fish/m2, or 5 to 10kg/m2, and should not exceed 20kg/m2. In circulating aquaculture, for example, the stocking density of turbot culture is 0.63kg/m3. By the 300th day, the stocking density reaches 48.8kg/m3. According to reports, turbot can be cultured at high density, reaching 25-30kg/m3, and up to 75kg/m3.
2. Feeding and management
(1) Water flow adjustment and water quality control ① The adjustment of pool water flow is based on the oxygen content, total ammonia nitrogen, NO2--N and other contents in the inlet and drainage. water flow. Generally, the dissolved oxygen in the pool water should be kept above 4mg/L, and the water at the outlet should not be less than 3mg/L; the total ammonia in the fish pond drainage should be <1.5mg/L, and NO2-<0.1mg/L. The water flow can also be adjusted according to the feeding situation of the pond fish. When the water temperature is stable and the feeding decreases, the flow should be increased. The flow rate is controlled at 4 cycles/24 hours. The water is quickly changed 0.5 to 1 hour after each feeding, and the water change amount is about 80%. ② Control of water temperature. According to the different suitable temperatures for different fish, control the temperature of the pool water so that the fish always live within the suitable temperature range and accelerate the growth of the fish. For example, the water temperature of 13 to 18°C ??is the suitable growth temperature for turbot; 16 to 21°C is the suitable growth temperature for flounder; the optimal water temperature for large yellow croaker should be controlled at 18 to 25 degrees; and for grouper, it should be controlled at 22 to 28 degrees. Spend. ③ pH control usually makes the pH of the breeding pond water alkaline. There are two commonly used control methods. One is to calculate the daily alkaline substance addition amount based on the daily feeding amount of each pond, and then weigh the required amount for each pond. Dissolve in water and splash all over the pond. The second is to add the required alkaline substances to the circulating pool, such as NaOH, Na2CO3 (soda ash), NaHCO3 (baking powder), CaCO3 (calcite, limestone), CaO (quick lime), Ca(OH)2 (slaked lime), etc., through water circulation, adjust the The final water is injected into each pool to adjust the pH. Two issues that need to be paid attention to during production are: first, ensure that the alkaline substances in the pool are poured evenly, and do not cause the local pH to be too high to avoid burning the fish; second, pay attention to safety, as alkaline substances are highly corrosive and should not be used during operation. Be careful to avoid injury.
(2) Feeding Most of the feed is artificially formulated pellet feed, and there is no bait table. Feeding is frequent, and in addition to daytime, feeding can also be done appropriately in the evening and early morning. When the water temperature is 23 to 28°C, feed 6 to 10 times a day. Please refer to the relevant parts of pond culture for feed planning, monthly distribution, feeding rate, and feeding changes related to water temperature. Sound should also be used to train fish when feeding, so as to form a conditioned reflex to focus on grabbing food. The principle of making the fish 80% full should still be adhered to when feeding each time, in order to improve feed utilization. Generally, bait is thrown near the water mouth.
The feeding strategy is based on the principle of quantitative feeding to avoid the negative impact of full feeding on the average food intake and feed utilization rate of fish. Determine the feeding amount according to actual conditions. Weigh the average fish weight at the beginning of each month, calculate the feed coefficient, determine the basic daily feeding amount at the beginning of the month based on the total weight, calculate the daily feeding increment based on the feed coefficient, and increase the feeding amount daily.
(3) Inspection and care work: Frequently check the condition of the inlet and drainage gates and fish traps.
Author: jnjy_hym 2007-1-19 16:57 Reply to this statement
--------------------- -------------------------------------------------- --------
5 Replies: Factory fish farming
Industrial farming of white shrimp is ten times or more than traditional farming methods. Welcome to visit. Absolutely Green and environmentally friendly! It has epoch-making significance and is your money-making tool. The process flow is: high-speed sewage treatment of fish ponds (mainly removing nitrite and ammonia nitrogen) -> sterilization and disinfection -> high-energy water (oxygen content per liter of effluent water is 10~90 mg adjustable). Funnel-type fish pond design, free remote infrared fish pond photography system. Full computer control and analysis of fish pond water quality parameters and scientific automatic feeding amount to ensure high-speed growth of fish and shrimp. Reference: /fish/fish_1.htm