Introduction to RAS farming project report and Ras fish farming Business Plan
Let us get into details of RAS farming project report and business plan.
These Recirculating Aquaculture Systems (RAS) are a new form of fish production systems, which actually bridge the gap between fish demand and supply. It is an intensive mechanism where the culturist has to provide the biological needs for the organisms to grow and develop. This new system encourages fish farming in a controlled environment unlike the traditional method, where fish are farmed in open ponds and raceways. The water used in these systems is recycled regularly for a better environment for the fish. Sometimes the tanks are supplied with fresh water other than the recycled water to compensate for the loss due to evaporation and splash out.
The traditional raceway systems grow fish and discard the water thereafter, which is generally termed as open or flow-through system. The RAS systems create a proper environment for the fish such as clean water, optimum temperature, adequate dissolved oxygen content, etc. These systems clean water using filters at various levels and also have an exceptional way of handling the waste.
The RAS fish farming project report describes the structure of the farming system and also at the end gives a rough estimate of the investment and profits associated with the system.
Benefits of the RAS system
These systems are considered very advantageous over open pond systems because of the following reasons:
- Intensive production
- Both water and land are conserved
- The flexibility of the location
- Choice of species and harvest flexibility
- Facilitate polyculture and monoculture at different growth stages
Read: Fish Farming FAQ.
Components of the RAS fish farming system
The system consists of several parts such as the tank for growing fish, a sump for removal of particulate matter, filter, oxygen injection tube, a pump for water circulation and ozone or ultraviolet sterilization unit. Each of the component and its functioning is described below.
Water supply unit
The enterprise should have a proper and adequate supply of water from resources like ground, wells or springs, etc. The water should be free from pollutants and should have relatively high hardness levels. The water from the municipal water supply unit can also be used but should be treated to remove the chlorine, fluorine and other chemical substances.
The water quality and quantity should be tested before the entire set up process to ensure an adequate supply of high-quality water. The RAS fish farming unit needs or consumes less water when compared to other techniques of fish farming. The general recommendations are 1-5 gallons of water for every pound of fish and around 10-25 gallons of water should flow every minute to grow fifty thousand pounds of fish each year.
The fish culture tank
The shape of the fish tanks can be rectangular, circular or oval in shape. The tanks with central drain and circular in shape are easier to clean and circulate water than the rectangular tanks. The design of the tank should be compatible with other components of the RAS system like the biofilter and sump.
The fish rearing tanks can be made of materials like plastic, concrete, metal, wood, glass, rubber and plastic sheeting. The main aim of the material used for the construction of the tank is that it should not leak, corrode and become toxic for the fish in it. The surface of the tank on the inner side should be smooth to avoid skin abrasions and infections to the fish and facilitate proper cleaning and sterilization.
The lightweight tanks when used in the system are durable and convenient to move and manage, but extra support is to be provided to prevent them from stretching while filling water. Tanks made of stainless steel are also considered good but are a little expensive. The plywood of the marine grade is inexpensive, but leak when not properly sealed. Tanks made of concrete are immovable structures, but economical to build. Generally, non-plastic materials are used as rubber liners for tank structures made of metal, wood, and concrete.
A simple biofilter consists of a wheel, barrel or box, filled with media that facilitates a large surface area for growing nitrifying bacteria. The biofilter can be made of materials like plastic, wood, glass, metal, concrete, etc. Very small fish farming units make use of plastic garbage cans or septic tanks. The size of the biofilter is directly related to the fish carrying capacity of the system because larger biofilters can assimilate more ammonia and help in higher fish production.
The main idea of the biofilter is to colonize nitrifying bacteria such that the water flowing through the biofilter when gets in contact with the bacteria on the surface media for a certain period of time converts NH₃ (ammonia) to NO₂ (nitrite) and to NO₃ (nitrate). The time of water contact with the media in the filter along with the depth and volume of the filter should be carefully calculated before the setup is made.
The biofilter media used in the RAS systems are generally made of corrugated plastic, Styrofoam, glass beads, lava rock, sand, gravel or any other similar material with large surface area. The efficiency of the biofilter depends on the quality and quantity of the surface area of the media within the filter. The basic properties of the biofilter media should be:
- High surface area
- A large number of pore spaces
- Easy to maintain
Size and type of filters
The size of the biofilter within the RAS system must suit or set well with the other components in the system and therefore three factors that should be considered while designing the filter are:
- The surface area of the media in square feet for the attachment of the bacteria.
- Ammonia loading, which implies the amount of ammonia required to convert one square foot of media in one day.
- Hydraulic loading, which indicates the quantity of water required per square foot of the media each day.
Generally, the configuration of biofilters is done in two ways i.e. through immobile media (called the submerged filters) and the emerged bed filters. Most commonly used submerged filter is the fluidized bed reactor (FBR), which consists of fine particles like sand dense plastic and glass beads in a container. Water flows through this media and fluidizes the suspended particles. It is believed that FBR offers greater surface area and helps in higher nitrification. These filters need to be dissolved oxygen to help the nitrification process. If the amount of dissolved oxygen is low, then the amount of ammonia converted reduces gradually.
Emerged filters are again classified into two basic types such as the trickling filter (TF) and rotating biological contactors (RBC). The advantage with these filters is that they do not need the addition of oxygen before or after the nitrification process because the filter itself supplies the required oxygen to support fish respiration. The trickling filter is designed such that water slowly comes down through the media column to help the process of nitrification. This waterfall process adds or aerates the water in the tank.
Starting a biofilter and the recirculation rates
The entire colonization of bacteria within the filter may take around one to three months. A new tank inoculated with a new seed bacteria from an existing system can shorten the startup time and provide high efficiency. The addition of bacteria obtained from commercial business dealers named under the specially selected strains of bacteria has not shown signs of faster growth. If the water is cool, then the bacterial activity slows down and makes the filter inefficient.
Every time the water is exchanged is termed as recirculation and its rate is defined per unit time. For example, the recirculation rate for a tank with 2500 gallon capacity supplied with a water pump of 45 gallons of water per minute is 25.3 tank volumes a day. The recirculation rate increases the Biofiltration and helps in greater nitrification with reduced ammonia levels.
Fish excreta and leftover waste food has to be prevented from accumulation and a sump is a part of the system which helps in the removal of all waste products from the tank. The presence of waste in the tank reduces the biological oxygen demand, decrease the dissolved oxygen content in the water and lower the carrying capacity of the tank. A sump is a form of the settling basin, the purpose is to concentrate and remove solid waste before the clog the biofilter. This sump is a separate tank kept in isolation from the fish tank and biofilter such that it can be cleaned regularly. The efficiency of the sump or clarifier is increased by using various filters made of plastic, sand, metal etc.
The size of the sump is decided on the basis of the size of the fish tank and biofilter. It also depends on the turnover rate of the system. To obtain maximum sedimentation of suspended particles, the volume of the sump and the flow rate through the sump should be adjusted properly. The average flow rate is estimated to be 90 gallons per minute.
Feed recommendations for RAS fish farming system
The feed for the fish should contain essential minerals and vitamins and is specially formulated for the fish species in the RAS systems. Other animal feed should not be used for fish and also the feed has to be chosen appropriately for the specific species in the fish tank. The recommended feed for fish in RAS systems is dry feed or floating pellets so that the health of the fish can be observed at the surface level. The feed should be stored properly in a dry place free of insects and rodents. Generally, cultured fish need feed that is 3-5% of their body weight. If fish refuse to eat, then it is an indication of a problem, so fish culturists should immediately check for the ammonia levels in the water. It is considered that low feeding happens in very high or very low water temperatures.
Oxygen management of RAS fish farming system
Oxygen levels in water help in higher production and addition of oxygen to water are essential for the following reasons:
- Respiration of fish in high-density tanks.
- The existence of aerobic bacteria on the biofilter.
- Decomposition of organic waste.
Oxygen has to be supplied to keep the fish and bacteria healthy and also it helps to maintain the biological oxygen demand within the water for the fish waste and unconsumed food. The demand for oxygen depends on several factors and is directly related to the density of the fish in the tanks, feeding rate, the temperature of water, nitrification etc.
Oxygen from the atmosphere is added to the tanks through surface agitation with aerators or large blowers. Surface agitators do not evenly distribute the oxygen in large commercial tanks, but blowers are effective in supplying oxygen evenly throughout the tank and also rotating the RBS mechanically.
Read: Aquaponics FAQ.
Temperature management in RAS fish farming system
The temperature within the tank should be regulated properly because the water temperature influences the feeding and growth rate of the cultured fish. The ideal temperature for bacterial nitrification activity is 85˚F. The temperature of water within the tank is maintained depending on the type of fish being reared. The water is heated by heating the entire building with space heaters or directly heating the water. High temperature and humidity in the room are controlled by ventilation with an electric fan. Heating water directly is an expensive process so generally solar heaters or heat exchangers are recommended.
Cost and profit analysis of RAS fish farming project report
The estimation of the RAS fish farms is given in USD, just for reference and should be always analyzed according to the location of the farm and its related currency structure. It is always recommended to have thorough market research before making a final analysis of the investment structure. The cost and profits may vary depending on the country of the farm and on the species being cultured. This report presented here is only to give a rough estimation of the project structure.
Initial investment (cost/hectare) for ponds with the RAS fish system installed =
- Small Size RAS farm: $280,000 (USD)
- Medium Size RAS farm: $330,000 (USD)
- Large Size RAS farm: $340,000 (USD)
Apart from these, there could be some fixed costs involved like land charges, etc. during the project, which should also be considered accordingly. The cost of pond preparation mentioned above in the table indicates the cost of lime, salt, fungicides, etc. and the cost of fingerling include the treatment of the fingerlings also.
Due to lower sludge discharge costs and high fish density of RAS compared to traditional fish farming, RAS can fetch more yield of fish hence more profits.
The average annual profit is expected to increase to $230,000 USD/ha and $300,000 USD/ha for medium & large farms with an implementation of the RAS fish system.
Profit is not observed during the initial years of investment, but slowly as the production improves profits start coming in.
Future of RAS fish farming in India
The RAS fish farming technology was launched in India as a pilot project and is considered as the most advanced method of producing high-quality fish around the year in a small area of land. This method is believed to be costlier than the traditional method and needs some extra advanced equipment like the mechanical and biological filters. In India, the fisheries department is planning to rear Genetically Improved Farmed Tilapia (GIFT) that is a breed of tropical fish. It is assumed that 40 cubic meters of the tank can produce about 4,000 fish in six months. Generally, this figure is estimated by considering the fact that normal fish farming produces 40 fish per 1 cent of the land. With RAS fish farming, the culturists can obtain two crops a year of about 1.5 tonnes of fish yield during each crop.
The minimum investment for a small RAS fish farming in India is estimated to be around 4.8 lakhs for a tank measuring 1 cent. The price of the fish in the market is considered to be around Rs 250 per kg, depending on the quality. The department of fisheries working under the Government of India provides half the amount of investment as a subsidy to the farmers or also facilitates banks to provide loans to RAS fish farmers. Farmers would also have to locate their farms in areas where there is a continuous supply of power, which is extremely important for the functioning of the RAS system.
Read: Goat Farming In India.