FutureFish RAS Technology
RAS is the acronym for Recirculating Aquaculture Systems. RAS fish farms are characterised by an integrated water treatment unit that constantly cleans the effluent water from the culture tanks in mechanical steps and bioreactors to remove solids and toxic nitrogen compounds that are excreted by the fish or shrimp. After being cleaned, the water can be reused and is pumped back to the holding tanks thereby closing the loop.
In contrary, in the “open” or “flow through” systems all the water passes through the culture tanks makes only once and then leaves the system often with a significant impact to the environment
The design of a RAS fish or shrimp farm is very complex and requires knowledge, expertise and the right technology. FutureFish RAS for fish and shrimp farming are the right choice to provide best conditions for successful production and represent a unique, eco-friendly and reliable way to farm fish at high densities in land-based, indoor tanks with a controlled environment.
Low Water Requirements
In our RAS facilities new water is added to the tanks only to make up for water loss due to splash out, evaporation and the backwashing water to flush out waste materials in the mechanical filters. With the high percentage of water recycling, our RAS systems are especially well suited to areas with limited water supplies and also enable the operation of marine farms away from the seashore and close to the markets.
The required quantity of water needed to successfully grow fish and shrimp varies with the farmed species and the farm size. As a general rule, 0.2 to 0.4 m³ of fresh water per day is needed for every ton of fish produced. For shrimp the required sea water intake is 0.3 to 0.5 m³ per day respectively (without optional water recovery).
The water can be taken from wells, municipal supplies and surface waters such as the sea for marine productions. Surface waters need to be sterilised before being fed to the RAS, but FutureFish has the technological solution for such a firewall system.
Reduced environmental impact
A significant reduction in water intake corresponds to a reduction in the amount of loaded effluent water. This limits the environmental impact, opens the possibility to polish the effluent for a discharge into municipal systems or to subsequently use the nutrient-rich effluents for a further biomass yield from an aquaponic plant production.
Less Land Requirements
FutureFish RAS farms allow fish to be stocked and safely raised at high densities, as their metabolic waste is mechanically flow-washed from the tanks and the water leaving the filter system back to the culture tanks is sufficiently oxygenized. As land space required per ton of fish is rather low and farms can be located in or near to urban areas where large areas are not available or very expensive.
Control of Water Temperature
The low water consumption in Futurefish RAS farms opens up the possibility to economically control water temperatures and to allow the aquaculturist to produce a fish species that could not be raised in a flow-through system in our geographic area. The water temperature in RAS can be maintained within an optimal range in order to maximize food conversion and provide best growth throughout the year without seasonal impact.
Control of Water Quality
FutureFish RAS farms permit a constant and reliable control of water quality, both to the benefit of the fish and shrimp but also for the final product. By maintaining dissolved oxygen at optimum levels, the fish have better food conversion rate and less stress. This positively contributes to their natural resistance towards diseases. In addition, the fish are isolated from potential environmental contaminants such as off-flavor caused by some algal growth and from potential pollution resulting from soil run-off or residual pesticides. All this guarantees biosecure aquafarming.
At a glance:
The benefits from a FutureFish RAS farm for fish and shrimp farming are:
• Constant control over water quality and production parameters
• No stock losses due to adverse environmental or weather conditions
• Highest possible biosecurity and feed control
• No use of chemicals, hormones, pesticides etc.
• No stock losses due to predators
• Less water usage than conventional aquaculture systems
• No adverse environmental impact
• Ability to manage effluent quality according to local regulations and ambient requirements
• Ability to use nutrient rich effluent water for further production of aquatic organisms (mussels, snails etc.) and plants (micro-/ macro algae, halophytes, aquaponic)
• Lower land space requirements because of highest production efficiency per unit tank area
Production / Economics
• Year round, constant and predictable outputs and harvests “just-in-time.
• Optimal growth rates because of water parameter adapted to specific requirements
• Efficient feed conversion and reduction of feed costs
• Reduced labor requirements
• Effective economy of scale by modular design
• Choice of species independent of farm location and/or ambient conditions
• Ability to grow species in urban environments and close to markets
• Flexibility in selecting species and market size to meet market requests
• No risk of escapees of non-indigenous species from farm
Description of the FutureFish RAS
The first step in cleaning the effluent water from the culture tanks is a mechanical filtration by a drum filter to remove uneaten pellets, feces and other solids. Our drum filters are made of PE plastic and are equipped with a heavy-duty nylon-mesh, and automatic back-washing control.
In addition to the solids the water is loaded with ammonia, a toxic product of the fish metabolism. To avoid toxic ammonia concentrations, the water is fed into the bioreactor by gravity. The biofilter tanks are filled with specially designed, floating biocarrier with a high specific surface area for the settlement of nitrifying bacteria, specialized in transformation the ammonia to nitrite and finally nitrate. The biocarrier are agitated by an intensive aeration (Moving-Bed BioReactor = MBBR).
A section of the bioreactor is used as pump sump. From here the water is pumped back to the fish tanks or shrimp raceways by energy-efficient, non-corrosive pumps. On its way the water flow passes low-head oxygenation systems to recover the oxygen concentrations required for the intensive farming.
In a side loop a part of the flow is pumped into a denitrification reactor. In here heterotrophic bacteria are reducing the accumulating nitrate in an anaerobic environment to nitrogen gas that is removed from the system. In a second loop, fine particles and also bacteria are removed from the water in a skimmer, enriched with locally generated ozone (O3).
Monitoring and operational safety
A sophisticated safety concept safeguards the fish stock. Redundant pumps, back-up systems and emergency oxygen diffusers in the culture tanks are some of the components of the life support concept in our farms.
All processes, power units and important water parameters are monitored by numerous sensors and controlled by industrial automation. If any disturbances or deviations from the predetermined data occur, staff will immediately be notified.
Our farm design is modular by means that any production capacity can be realized by multiplying the standard modules avoiding up-scaling risks. The size and shape of the culture tanks that are connected to the water treatment unit is adapted to the needs of the respective species.
Advantages of the modular design are:
• No risk during a scaling-up of farms for higher production capacities since it is realized by multiplying standard units (modules)
• Reduced investment due to series production
• One technology with similar components in all farms for easy maintenance