Factory fish farming refers to an efficient fish farming method that uses the principles of architecture, electromechanical, chemistry, automatic control and other disciplines to implement semi-automatic or full-automatic management of water quality, water temperature, water flow, feeding, sewage discharge, etc. in fish farming production, always maintaining the best physiological and ecological environment of fish, achieving healthy and rapid growth, maximizing the yield and quality of fish per unit water body, and not producing pollution inside and outside the aquaculture system.
Factory fish farming is the most advanced fish farming method at present, which has many advantages, such as less land occupation, high yield, little influence by natural environment, continuous production all year round, high economic benefit, automatic operation management and so on. In addition, closed circulating water fish culture is not easy to pollute the marine environment and consumes less water, which is an environmentally friendly and green farming method. Nowadays, mariculture is moving towards the direction of sustainable development with marine environmental protection as the core. Therefore, industrialized fish farming is one of the best ways to meet the development trend of mariculture. Factory fish farming is a high-input, high-output and high-risk industry with large investment, strict management and strong technology, which is suitable for large and medium-sized enterprises with strong capital, strong technical force and rich management experience.
China's industrial culture started late, and its technical equipment and automatic control level were low. Although it has developed, it belongs to a relatively primary high-density indoor culture, but it is basically an open flowing water culture with aeration and running water. The cultured species include abalone, flounder and American red fish. However, most varieties are basically cultivated in a factory way, forming a supporting system.
I. Types of industrialized fish farming
There are many forms of industrialized fish farming on land, mainly including ordinary running water fish farming, warm running water fish farming and circulating running water fish farming.
1, common running water fish culture
Use natural seawater that has undergone simple treatment (such as sand filtration), and directly flow into the fish pond without heating, and the used water is directly discharged into the sea. This method is simple in equipment and low in investment, suitable for short-term or low-density farming in temperate regions of southern China, and is the lowest stage of industrialized fish farming. It is suitable for the cultivation of marine carnivorous fish such as snapper, sea bass, grouper and flounder.
2. Warm water fish farming
In the early 1960s, it was the earliest industrialized fish farming method developed in Japan. It uses natural hot water (such as warm water wells and hot spring water), warm drainage water from power plants and nuclear power plants or artificially heated seawater as the source of fish farming, and after simple treatment (such as temperature regulation), it enters the fish pond, and the used water is not recycled. Due to the limited geothermal water and hot spring resources, this cultivation method is mainly used for the comprehensive utilization of warm drainage in factories. At present, warm water fish farming is very popular in Japan, Russia, the United States, Germany, Denmark, France and other countries. China has developed rapidly in recent years. For example, dozens of warm-water fish farms have been built in Jiaodong, Shandong Province, covering an area of about 200,000 square meters, with an annual output of all kinds of high-grade marine fish 1000 tons, including flounder, halibut, black gill fish, six-line fish and snapper. There are three main ways to adjust the temperature of these fish farms: ① coal-fired boiler heating+natural seawater type, such as Gushan fish farm in Weihai, Shandong Province and Zhenshan fish farm in Rongcheng; (2) Power plant warm drainage+natural seawater type, such as fish farming in Qingdao Huangdao Power Plant and Weihai Huaneng Power Plant. ; (3) Warm water well+natural seawater type, such as the fishing ground of Qiujia Fishery Company in Rongcheng City and Penglai Fish Culture Experimental Factory in Shandong Province. This fish culture method has simple process and equipment, low yield and large water consumption, and is the primary stage of industrialized fish culture.
3, circulating water fish culture
Also known as closed circulating water fish culture, its main feature is that the water discharged from fish ponds needs to be recycled. After aeration, sedimentation, filtration and disinfection, according to the physiological needs of different breeding objects at different growth stages, the temperature is adjusted, oxygen is increased, and an appropriate amount (1 ~ 10%) of fresh water (the part lost or evaporated in the system circulation) is added to the fish pond. This system also needs water quality monitoring, flow control, automatic dosing, sewage discharge and other devices, which are automatically monitored by the central control room. It is a high-tech fish farming system with the strongest integrity, the highest level of automatic management and no environmental pollution inside and outside the system. It is the highest realm of industrialized fish farming and will surely become the mainstream and development direction of industrialized fish farming. At present, the region with the highest technical level in the world is Europe, and some countries have been able to export complete sets of fish farming equipment. The unit output of circulating water fish culture has reached 100 ~ 300 kg/m2.a, that is, 750 ~ 1500 kg/m2.a, and only 1 ~ 10% supplementary water is used, so the automatic water purification ability is very strong.
Second, the factory fish culture facilities
According to different mariculture objects and the requirements for water quality, the industrial mariculture technology currently used has different routes, involving a wide variety of equipment, each with its own characteristics. Generally speaking, the two industrialized fish farming methods, ordinary running water fish farming and warm running water fish farming, require less equipment. Ordinary running water fish culture is based on ordinary pond culture, and sand filters are added to filter the seawater or well water, and the wastewater after culture is directly discharged into the sea. On the basis of running water fish culture, warm water fish culture has added temperature regulation equipment and warm water drainage pretreatment equipment, such as boilers and heat preservation greenhouses. It's not complicated The real factory fish farming is circulating water fish farming, which requires more equipment and advanced technology. Let's focus on it below.
Author: jjy _ hym2007-1-1916: 57 reply to this speech.
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2. Factory fish farming
The seawater industrial aquaculture system mainly consists of the following systems: (1) fish pond system; (2) water purification system (3) automatic monitoring system, etc. (4) Automatic feeding system and other auxiliary systems.
1. The fish pond system includes fish ponds, water inlet and outlet pipes and fish stopping equipment. Fish ponds are generally located indoors, and concrete structures or glass fiber reinforced plastic pools are mostly polygonal, rectangular and circular, with an area of less than 50m2 and a depth of about 1m, and the bottom is designed with a certain slope to facilitate sewage discharge. The water inlet pipe of water supply and drainage system is plastic pipe, and the pipe diameter varies according to the water supply. The water inlet is located at the upper part of the fish pond (30cm from the upper edge), the water outlet is located at the center or bottom side of the pond, and the drainage pipe is connected with the aeration tank or sedimentation tank. The fish catching equipment is a metal net or grid foil arranged at the drainage outlet, and the aperture is based on the fact that it is conducive to sewage discharge but does not escape fish.
2. Water purification treatment system Water purification treatment is the key to the whole circulating water factory fish culture. The whole water quality treatment system includes the following links: 1 solid waste removal; 2, removing water-soluble harmful substances; 3 sterilization and disinfection; ④ oxygenation; 5 temperature adjustment; 6 water quality measurement and control.
(1) The thickness of self-purification sediment is as high as 10cm per year for the removal of solid waste from traditional beach culture ponds. The density of industrialized fish farming is relatively high, and the amount of solid waste produced is larger, including fish feces, residual bait and other sundries (fibers, particles and fragments). Organic matter accounts for about 80%, which is the main source of aquaculture water pollution.
Filter bed filtration is a widely used method. Water flows from the upper layer to the lower layer, which is called forward filtration, and from the lower layer to the upper layer, which is called reverse filtration. The filtration effect is similar, but forward filtration is easy to block, and reverse filtration is difficult to remove solid substances.
Compared with sand filter, sieve filter has advantages in volume, installation and backwashing operation.
The fixed mesh filter, that is, the quick-opening scrubber, is cylindrical in shape and equipped with a mesh basket inside. A filter screen and a water flow filter screen are arranged in the basket to filter out solids larger than the mesh, and the basket is taken down manually and regularly after being piled up. According to the different requirements of mariculture, the mesh size ranges from 60-200 mesh/inch. Its characteristics are convenient installation and simple operation. In the seawater circulating treatment system, it is often used to filter solids with particles larger than 0.5 mm before the pump, and the unit filtration capacity is10 ~100 m3/h. ..
Part of the circular rotary screen of the rotary screen filter is submerged in water, and water flows through the inner surface of the rotary screen to filter impurities. A sewage pool is arranged on the inner side of the screen above the water surface, and a nozzle group is arranged at the corresponding position on the outer side of the screen. During automatic backwashing, the high-pressure water sprayed from the nozzle flushes the solid matter filtered out of the screen into the sewage pool below, wraps it and discharges it. Seawater mesh number is 80 ~ 150 mesh/inch, backwashing water pressure is 0.2 ~ 0.6 MPa, unit filtration capacity is 14 ~ 400 m3/h, and power consumption is less than 1.5KW/h/h ... In addition, there are chain moving screens and vibrating screens. Rotating sieve filtration has a good application effect in mariculture plants, which is characterized by continuous operation and good anti-clogging performance.
Automatic cleaning filter is a new type of automatic filter, which combines the operating characteristics of fixed screen structure with the performance advantages of rotating screen. The shell mechanism is shaped like a quick-opening dirt remover. A stainless steel brush driven by 1 1KW motor is designed in the center, which rotates around the inner wall of the filter screen to brush off the filtrate attached to the surface of the filter screen, and then the discharge is controlled by the drain valve. If the stainless steel brush is replaced by a suction scanner, the suction port of the scanner can suck away particulate impurities and remove them during rotation. It is characterized by continuous flow and little discharge during backwashing. It can be cleaned and discharged according to pressure difference or timing control, and the cleaning cycle is electronically monitored by computer chip. Filter materials are divided into stainless steel 3 16 (pore size 0.2 ~ 3.5 mm) and woven filter (pore size 0.025~0.5mm). It is suitable for filtration systems with large flow (Qmax= 1000m3) and large filtration area (10000cm2), and it is an advanced screen filter in aquaculture plants at present.
Foam separator Foam separator can effectively remove suspended solute from water, which is one of the key technologies for treating and screening seawater. Its principle is to introduce air into the treated water body, so that the surface active substances in the water are adsorbed by tiny bubbles and float to the water surface with the bubbles to form foam, and then the foam on the water surface is separated, thus achieving the purpose of removing dissolved and suspended pollutants in wastewater. The application test shows that the solid content of dirt collected by foam separator can reach 39%. It is especially effective for low-concentration aquaculture water, which not only eliminates ammonia nitrogen sources such as protein, but also increases oxygen, and the ozone injection effect is better.
(2) After removing water-soluble harmful substances and solid substances by biofilm technology, the water-soluble substances in the circulation system mainly exist in the form of "three nitrogen", and ammonia nitrogen (NH3-N) is highly toxic, which can quickly enter the blood of fish through gills and skin, interfere with the normal tricarboxylic acid circulation of fish, change the osmotic pressure of fish, and reduce the utilization ability of oxygen in water, thus affecting the growth of fish; Nitrite nitrogen (NO-2-N) can quickly penetrate into fish, which leads to the inactivation of hemoglobin combined with oxygen in blood and makes it become hemoglobin, thus losing its oxygen-carrying function, which is life-threatening in severe cases. Nitrate nitrogen (NO-3-N) is generally considered to be very toxic, but with the continuous metabolism of nitrogen and the accumulation of total nitrogen, too high concentration will also affect the growth of fish, make the color change of fish worse and reduce the meat quality. These water-soluble substances are generally treated by biofilm technology, and the equipment mainly includes submerged biofilter, trickling filter, water purifier and plant purifier.
Author: jjy _ hym2007-1-1916: 57 reply to this speech.
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industrial fish farming
The submerged biofilter is made of carbon steel lined with rubber or wrapped with glass fiber reinforced plastic. An air diffuser (the ratio of ammonia nitrogen nitrification to oxygen consumption is 1: 4.57) and a biological filler are arranged in the submerged biofilter to form a biological bag (ammonia nitrogen treatment capacity is114 ~ 200 g/m3 d). Biological filler is the carrier of nitrifying bacteria, which can be divided into hard filler and soft filler, both of which are required to be non-toxic. The hard filler is polyethylene, polypropylene water drop or honeycomb filler, or microporous ceramic ring or biological stone. The soft filler is made of vinylon fiber with a diameter of 7μm, which can be freely dispersed in water with a specific surface area of 2000m2/m3, and the ammonia nitrogen removal rate is as high as 80%. However, it is easily disturbed by other factors in the water, which affects the use effect. In addition, ultrafine active materials are added to the carrier, and microorganisms are immobilized, which enhances the processing capacity. Biological bags are generally arranged in units. In order to improve the treatment effect, beneficial water-purifying bacteria such as NO-2 and NO-3 nitrifying bacteria and NO-2 and NO-3 reductase can be added.
The structure of the trickling filter is similar to that of the submerged filter, and the volume ratio of the trickling filter to the submerged filter is 1: 2, which receives the filtered water of the submerged filter in the form of droplets. Control the water level to filter materials (biological filter balls, elastic fillers, etc.). ) is in a wet state where gas and water are alternately attached, and gaseous wastes (N2, CO2, CO) in the water overflow during the trickling process. In addition to the tank structure, there is also a trickling filter formed by stacking multiple plastic boxes (with holes at the bottom), which is economical, reasonable and practical.
The water purifier comprises a biological turntable, a biological rotating ball and a biological rotating drum. The principle is to use microbial adsorption to form biofilm, which can not only increase oxygen, but also absorb harmful ammonia nitrogen and nitrite by rotating alternately in air and water. Under the action of enzymes, some organic substances directly synthesize organic substances in microorganisms, thus purifying water bodies. This device has the functions of immersion filtration and trickle filtration.
The device for raising fish and growing vegetables mainly connects the culture plates, troughs, bowls, plates and substrates in the fish-raising circulation system in series, cultivates vegetables and flowers without soil, and removes nitrate nitrogen by using the absorption of nitrate by plant roots. This is the most effective key technology to solve nitrogen cycle in closed culture system at present, which provides a feasible way to realize zero emission and waste-free production and has good ecological effect. Plants adapted to seawater environment are some salt-tolerant varieties, or gradually domesticated by some freshwater plants.
(3) Sterilization and disinfection In order to avoid the side effects caused by chemical drugs, physical sterilization and disinfection are often used in seawater industrial fish farming.
The ozone generator generates ozone according to the discharge principle, which is extremely unstable and will be quickly reduced to oxygen, with strong oxidation ability and strong sterilization effect. Ozone is heavier than oxygen, which can increase the dissolved oxygen in water, adjust the pH value of water, especially when combined with ultraviolet rays, which can greatly reduce BOD and COD values, make nitrite reach a very low limit, transform ammonia nitrogen into nitrate, and improve the water quality of aquaculture. The sterilization efficiency is better than chlorine and sodium hypochlorite. In the application of seawater industrial aquaculture, the dosage is determined according to the specific aquaculture objects and water quality conditions. Generally, the maintenance concentration of culture is (0.08 ~ 0.2) mg/L, and the treatment concentration is (1~1.5) mg/L. The leakage of residual ozone can be solved by repeated circulation, activated carbon adsorption and heating.
The ultraviolet sterilizer designs a cylindrical ultraviolet lamp tube in the water pipeline, and directly radiates ultraviolet rays with the wavelength of 230 ~ 270 nm to the surrounding flowing water through the ultraviolet lamp, thus achieving the effect of sterilization and algae elimination. The transparency of water quality has a great influence on the irradiation effect. The irradiation thickness is controlled within 20mm, the irradiation time is longer than 10s, and the irradiation dose is 1.0× 104 mV s/cm2. At the same time, we should pay attention to prevent the refraction of ultraviolet rays.
(4) Oxygen Increase and Temperature Adjustment In the seawater industrial culture system, fish ponds, foam separation and biological filtration all need a lot of oxygen (about 7.57kg per ton of fish every day), and roots blower and vortex aerator are generally used, among which three leaves roots blowers has good stability and low noise effect. Impeller aerator has high aeration efficiency, simple structure and convenient use, and has a good application in the water quality regulation tank and secondary tank of fish farm. In recent years, there are also methods to increase dissolved oxygen in water by using pure oxygen, liquid oxygen and molecular sieve oxygen enrichment devices (purity above 90%). High-efficiency gas-water mixing device and gas-water mixing technology such as jet, spiral and mesh diffusion are adopted, so that water molecules become smaller and easier to mix, so that dissolved oxygen in water reaches saturation and supersaturation, the oxygen utilization rate is improved, and at the same time, it has sterilization and anticorrosion functions. The device can also be used for gas-water mixing of ozone.
(5) In addition to boiler tube heating (mainly using hot water boilers) and electric heating (in the form of rods, tubes and wires), combined heat pump cold and hot water units and other equipment are also used to adjust the water temperature. The water temperature is controlled by computer, and the temperature of the pool water is controlled by controlling the indoor temperature. Because there is less water and the density of fish is high, the temperature control mainly focuses on cooling rather than heating.
(6) Water quality monitoring and control The overall function and effect of industrialized fish farming system depends on the monitoring and control of water quality. Modern automatic monitoring system can monitor water quality in the whole process, and realize automatic monitoring, alarm and automatic start of related equipment control. In addition, the factory farming system also involves automatic monitoring system and automatic feeding system, and involves the application of computer monitoring, water pump, automatic feeding machine, underwater sweeper and other equipment.
Author: jjy _ hym2007-1-1916: 57 reply to this speech.
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4. Factory fish farming
Third, the breeding technology
The main differences between industrial fish culture and still water pond culture are: the pond area is small, the water in the pond is constantly flowing and exchanging, the source of water-soluble oxygen in the pond depends on running water or mechanical oxygenation, there are few natural bait organisms, the fish nutrition comes from artificial feeding, the fish excrement and other substances in the pond water are discharged in time with the water flow, and the water quality is fresh; The stocking object is swallowing fish, with simple species, high density and high yield.
1, fish stocking
Fish suitable for industrial farming are usually carnivorous and high-quality species, such as eel, flounder, turbot and grouper. The fry size is generally 50 ~ 150 g to meet the specifications of edible fish in that year.
Whether the density of density farming is reasonable or not also determines the benefit of the whole factory farming. Breeding density should be determined according to water source, water quality, infrastructure, technology and management level. Generally, running water fish culture is generally 50 ~ 200 fish /m2, or 5 ~ 10 kg/m2, which should not exceed 20kg/m2. Taking circulating water culture as an example, the stocking density of turbot was 0.63kg/m3, and by the 300th day, the breeding density reached 48.8kg/m3. It is reported that turbot can be cultured in high density, reaching 25 ~ 30 kg/m3, and the highest can reach 75 kg/m3.
2. Feeding management
(1) Water flow regulation and water quality regulation ① The regulation of pond water flow is based on the oxygen content, total ammonia nitrogen and NO2-N content in the incoming and outgoing water. 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 3 mg/L; Total ammonia discharged from fish ponds
(2) The feed is mostly artificial pellet feed, and there is no bait table. Feeding frequency is more, besides daytime, evening and early morning can also be properly fed. When the water temperature is 23 ~ 28℃, feed it 6 ~ 10 times a day. The feeding plan, monthly distribution, feeding rate and the relationship between water temperature and feeding strains can be referred to the relevant parts of pond culture. Fish should also be trained in audio frequency when feeding, forming a conditioned reflex to concentrate on grabbing food. In order to improve the utilization rate of feed, it is still necessary to adhere to the principle of making fish eight times full at a time. Bait is usually thrown near the nozzle.
The feeding strategy is based on the principle of quantitative feeding to avoid the negative impact of total feeding on the average food intake and bait utilization rate of fish. Determine the feeding amount according to the actual situation. 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 each month according to the total weight, calculate the daily feeding increment according to the feed coefficient, and increase the feeding amount every day.
(3) Inspection and nursing work: check the intake and drainage gates and fish barriers at ordinary times.
Author: jjy _ hym2007-1-1916: 57 reply to this speech.
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5 Reply: Factory fish farming
The industrial culture of Penaeus vannamei is ten times or more than that of traditional culture. Welcome to visit. Absolutely green! It has epoch-making significance and is a sharp weapon for you to make money. The technological process is: high-speed sewage treatment in fish ponds (mainly removing nitrite and ammonia nitrogen)-> sterilization and disinfection->; High-energy water (the oxygen content of effluent is adjustable between 10 ~ 90mg/l). A funnel-shaped fish pond is designed and a long-distance infrared fish pond photography system is introduced. Through computer control and analysis of fish pond water quality parameters and scientific automatic feeding quantity, the high-speed growth of fish and shrimp is ensured. Reference:/fish/fish _1.htm.