Ras Aquaculture: Things You May Want to Know

Overall Layout and Planning ProcessThe layout and planning of a land-based industrial recirculating aquaculture workshop are divided into two phases: the Planning Phase and the Design Phase.1.Planning PhaseStep 1: Determine Aquaculture SpeciesThe first step is to select the aquaculture species and conduct a feasibility analysis to determine the return on investment (ROI). Different species require varying scales of investment and equipment specifications. Failure to define the species will hinder decisions on capital allocation and equipment selection.Step 2: Determine Investment ScaleBased on the selected species, combined with available capital and land resources, develop an overall blueprint for the facility. Determine the number of construction phases and the scale of each phase.Step 3: Determine Production Output and Stocking DensityThe final step in the planning phase is to define the production output and stocking density for the first phase. These parameters are essential for calculating the required aquaculture area and designing the workshop layout. 2.Design PhaseIn the design phase, the size of the aquaculture area should be determined based on the aquaculture yield and density determined in the first phase, and the model and parameters of the equipment should be determined.Layout of land-based factory based circular aquaculture workshop1. Functional zoning1) Breeding areaThe breeding area is the core of the workshop, and the breeding pools are arranged in an orderly manner, which can be flexibly set according to the breeding varieties and scale. The shapes of aquaculture ponds are diverse, such as circular ponds with uniform water flow, which are conducive to collecting pollutants; The square rounded pool has a high utilization rate of space. The layout of the breeding area should ensure that staff can easily carry out feeding, inspection, fishing and other operations, and appropriate passages should be reserved between pools.2) Circulating water treatment areaVarious water treatment equipment, such as microscreen drum filters, biochemical filters, ultraviolet sterilizers, etc., are centrally placed in the circulating water treatment area. This area needs to be close to the aquaculture zone to shorten the pipeline length, reduce water flow resistance and energy loss. The water treatment equipment is arranged in sequence according to the process flow to ensure that the effluent from aquaculture reaches the standard of recycling after being treated layer by layer.3) Supporting facilities areaThe supporting facilities area includes distribution rooms, control rooms, feed storage rooms, drug storage rooms, etc. The distribution room should ensure stable power supply, while the control room is used for centralized monitoring of various parameters of the aquaculture system, such as water temperature, water quality, dissolved oxygen, etc., in order to adjust the aquaculture environment in a timely manner. The feed storage room should be kept dry and ventilated to prevent the feed from getting damp and moldy; The drug storage room must comply with relevant safety regulations, classify and store drugs for easy access.2. Logistics and Water Flow1) LogisticsPlan clear material transportation channels from the workshop entrance to the breeding area, supporting facilities area, etc., to ensure smooth transportation of feed, fish fry, equipment and other materials. The width of the channel should meet the requirements for transportation vehicles or handling tools to avoid congestion.2) Water flowDesign a reasonable water flow path. After the aquaculture wastewater is discharged from the aquaculture pond, it is sequentially filtered by a microscreen drum filter to remove large solid waste particles, and then enters a biochemical filter for biological treatment to degrade harmful substances such as ammonia nitrogen. It is then disinfected by a UV sterilizer and finally transported back to the aquaculture pond through equipment such as a water pump, forming a closed circulation system. The direction of water flow should avoid detours and intersections as much as possible to reduce head loss.3.Key Design Points for Land-Based RAS Workshop（1） Key points of aquaculture area design1. Design of aquaculture ponds1) Shape and SizeCircular aquaculture ponds generally have a diameter of 6-8 meters, a depth of 1.5-2 meters, and a conical bottom for easy collection and discharge of pollutants. The square rounded pool edge is 6-8 meters long, with a side height of 1.2-1.5 meters. The bottom corner is designed with rounded corners to reduce dead corners in water flow. The size of the aquaculture pond should be determined based on the growth habits and breeding density of the aquaculture species to ensure sufficient activity space and growth environment for fish.2) Material selectionCommon types include galvanized corrugated steel with canvas pool, PP material pool, brick mixed water mud pool, etc. Galvanized corrugated steel with canvas pool construction is convenient, cost-effective, and has certain flexibility and durability; PP material pool is corrosion-resistant, easy to clean, and has a long service life; The brick mixed water mud pool is sturdy and durable, with good insulation performance, but the construction period is long and the cost is high. Suitable materials can be selected based on actual needs and economic conditions.2. Vertical flow sedimentation deviceThe vertical flow sedimentation device plays an important role in the land-based factory based recirculating aquaculture workshop. From the perspective of solid waste treatment process, it is a key link in the initial purification of water quality. During the aquaculture process, large particles of impurities such as residual bait and feces produced by fish will enter the vertical flow sedimentation device with the water flow. Due to its special vertical flow design, the flow velocity gradually slows down during the upward process, causing heavier solid particles to gradually settle to the bottom under the action of gravity, achieving preliminary solid-liquid separation. Sedimentable particles with a particle size greater than 100 microns can be removed through a vertical flow settler. According to statistics, vertical flow sedimentation can handle 80% of solid particles. This effective interception can prevent them from entering more refined water treatment equipment, reduce the risk of equipment blockage, and extend the service life of the equipment.3. Breeding density and layout of breeding ponds1) Breeding densityDetermine a reasonable breeding density based on factors such as breeding species, pond size, and water treatment capacity. Excessive breeding density can lead to water quality deterioration, disease growth, and other issues, while excessively low density can affect breeding efficiency. For example, sea bass is cultured in a circular pool with a diameter of 6 meters and a depth of 1.5 meters, and the breeding density can be controlled at around 50kg per cubic meter of water.2) Layout of aquaculture pondsAquaculture ponds can be arranged in rows or columns, with sufficient space left between rows and columns to facilitate personnel operation and equipment maintenance. The general spacing between rows is 1.2 meters, and the spacing between columns is 2 meters. The vertical flow sedimentation device is placed between two breeding ponds.（2） Key points of design for circulating water treatment area1. Solid particulate matter treatment areaThe removal of solid particulate matter is an important step in the water treatment of recirculating aquaculture systems, and is usually the first step in water treatment. The core method for removing solid particles in recirculating aquaculture is physical filtration. Through mechanical filtration, gravity separation, and other methods, suspended particles, feed residues, fish manure, and other solid substances in water are intercepted and removed to purify water quality. According to the size of solid particles, the process of removing solid particles includes three steps: pretreatment, coarse filtration, and fine filtration. The vertical flow settler is the first pre-treatment process and needs to be installed next to the breeding pool in the breeding area. The microfiltration machine for coarse filtration and the protein separator for fine filtration need to be installed in the circulating water treatment area.2. Microfiltration machineSelect a microscreen drum filter with appropriate treatment capacity based on the scale of aquaculture and wastewater discharge. The filter aperture of a microscreen drum filter is generally 200 mesh. The specifications of the microscreen drum filter should be selected based on the circulation capacity of the system design. The larger the circulation volume, the larger the specifications of the microscreen drum filter. Generally, for 500 cubic meters of aquaculture water, a microfiltration machine with a water capacity of 300-500 tons per hour should be selected. The microscreen drum filter should be installed near the drainage outlet of the aquaculture area to minimize the residence time of wastewater in the pipeline and avoid solid waste settling and blocking the pipeline. Ensure the levelness of the microscreen drum filter during installation to facilitate normal operation and maintenance of the equipment.3. Pump poolThe circulating water aquaculture pump pool is the core component of the circulating water aquaculture system, responsible for the circulation, filtration, and transportation of water bodies. The rationality of pump pool design directly affects the operational efficiency and water quality stability of the aquaculture system.1) The function of the pump poolProvide power supportThe pump pool, as the "heart" of the entire circulating water system, is equipped with a water pump that is responsible for extracting treated water from the sedimentation tank or other treatment processes and transporting it to the aquaculture tank. By operating the water pump, sufficient kinetic energy is given to the water body, overcoming pipeline resistance and water level differences, ensuring that the water flow can circulate continuously and stably between various areas, and maintaining the normal operation of the aquaculture system. Without the power provided by the pump pool, the entire circulating water process will come to a standstill, and the living environment for fish will rapidly deteriorate.Buffer and voltage stabilizationIt can buffer pressure changes caused by pump start stop or water flow fluctuations, avoiding impact damage to pipelines and equipment. When the water pump suddenly starts, a large amount of water is quickly sucked into the pump pool. At this time, the larger volume of the pump pool can accommodate the instantaneous influx of water flow, ensuring a smooth transition in flow velocity and preventing excessive water pressure from impacting subsequent pipelines; Similarly, when the water pump stops running, the remaining water in the pump pool can be slowly released to maintain a certain water pressure in the system, ensuring that some equipment (such as the microbial community in the biochemical filter) is still in a relatively stable working environment and guaranteeing the sustainability of water treatment effectiveness.2) Key points of pump pool designVolume determinationThe capacity of the pump pool needs to take into account factors such as aquaculture scale, pump flow rate, and system operation stability. Generally speaking, the volume of the pump pool should account for 8% -9% of the entire aquaculture water body. Ensure that there is sufficient buffer water in the pool during the start and stop of the water pump to prevent emptying or overflow.Internal structure optimizationA guide plate can be installed inside the pump pool to guide the water flow smoothly into the suction port of the water pump and improve the efficiency of the water pump; A liquid level gauge can also be added to monitor the water level in the pool in real time, and linked with the water pump control system to achieve automatic start stop, further optimizing operation management and improving the performance of the entire circulating water aquaculture system. The pump pool should have an overflow design. When the water temperature is too high, it can be drained through an overflow pipe to prevent water from overflowing the pump pool.Location of pump poolThe pump pool is located below the microscreen drum filter, at the lowest position of the entire circulating water system. The water flows directly into the pump pool after being filtered by a microscreen drum filter.4. Design points of protein separatorProtein separators are mainly used to remove small suspended particles below 30 μ m and some soluble organic matter, while also having certain functions of oxygenation and decarbonization gas. The protein separator is located behind the pump tank, and the water from the pump tank enters the biofilter after passing through the protein separator（3） Design points of biological filterThe biofilter in the recirculating aquaculture system is one of the core components of water treatment. Its main function is to degrade harmful substances such as ammonia nitrogen and nitrite in water through the action of microorganisms, and maintain water quality stability. The volume of the biological filter and the amount of biological packing directly affect its treatment efficiency, operational stability, and overall performance of the aquaculture system.1. Volume of biological filterThe volume of the biofilter in the recirculating aquaculture system should be determined according to different aquaculture species. For example, the low biological carrying capacity of South American white shrimp results in a lower feeding amount in cubic water bodies. Therefore, the proportion of the volume of the biological filter to the total aquaculture water is relatively low. The volume of biological filter tank for breeding carnivorous fish such as Siniperca chuatsi and Perch is 10% -20% larger than that for herbivorous fish such as grass carp and crucian carp due to the large amount of nitrogen containing waste discharged, so as to strengthen the water purification capacity and meet their demand for high-quality water quality. Taking sea bass as an example, the volume of the biological filter should account for 50% of the entire aquaculture water.2. Multi stage filtration and hydraulic retention timeThe longer the hydraulic retention time in the biological filter, the better the removal effect of ammonia nitrogen sub salts. The hydraulic retention time is determined by the volume of the biofilter and the number of stages of multi-stage filtration. The larger the volume of the biological filter, the more layers it filters, and the longer the hydraulic retention time. Therefore, when designing biofilters, it is advisable to achieve multi-stage filtration as much as possible3. Quantity of biological fillersThe core of a biological filter is the biological filter material, and the quantity of biological filter material determines the nitrification capacity. The filling ratio of biological filter material should ideally reach 40% -50% of the biological pool.4. Aeration systemOxygen can be the limiting factor for nitrification rate in biofilters, as its content in the water is low and it is subject to competition from heterotrophic bacteria. 4.57g of oxygen is required for every 1g of ammonia nitrogen to be oxidized into nitrate nitrogen. The growth rate of nitrifying bacteria decreases when the dissolved oxygen is below 4mg/L. Therefore, the biological filter must maintain sufficient dissolved oxygen to ensure the operation of the nitrification system.An aeration disc with a diameter of 215mm and a gas flow rate of 2m3/h is installed at the bottom of the biological filter. Two Roots blowers with a power of 5.5-7.5kw (or high-speed centrifugal fans) and a gas flow rate of 4.5m3/min are equipped to aerate the biological filter and allow the biological packing to fully roll.4） Key points of disinfection and sterilization design1. Selection and installation of ultraviolet sterilizersSelect a UV sterilizer with appropriate power and diameter according to the requirements of circulating water flow rate and water quality. The ultraviolet sterilizer should be installed on the circulating water pipeline, near the inlet of the breeding pool, to ensure that the treated water is fully disinfected before entering the breeding pool. During installation, attention should be paid to avoiding pipeline leakage and ultraviolet radiation leakage to ensure the safe operation of the equipment. 2. Other disinfection methodsIn addition to ultraviolet sterilization, ozone disinfection, chlorine disinfection and other methods can also be used according to the actual situation. Ozone disinfection has the advantages of good sterilization effect and no residue, but it requires specialized ozone generators and exhaust gas treatment devices; Chlorine based disinfection has a lower cost, but improper use may cause toxicity to fish, and strict control of dosage and residual chlorine concentration is required.（5） Design points of oxygenation system1. Gas sourceThe dissolved oxygen in recirculating aquaculture is crucial, as the level of dissolved oxygen determines the density of aquaculture. From the perspective of system composition, the oxygenation system mainly includes the gas supply part, gas transportation, aeration device, and supporting control system. The gas supply can come from air compressors, oxygen concentrators, or liquid oxygen tanks. Liquid oxygen tanks can provide a large amount of high concentration oxygen in a short period of time and are commonly used in large-scale industrial aquaculture to ensure sufficient dissolved oxygen in the aquaculture water under high-density aquaculture loads. When designing a circulating water workshop, if there is a liquid oxygen gas source, it is recommended to choose liquid oxygen as the first choice. So it is necessary to leave space outdoors for installing liquid oxygen tank and design corresponding air supply pipelines. If there is no liquid oxygen, an oxygen generator can be installed as the oxygen source. This requires leaving space for the oxygen generator in the water treatment area2. Oxygen coneOxygen cone is an efficient oxygenation device in recirculating aquaculture systems. Its unique design and working principle make it perform well in high-density aquaculture and environments that require high dissolved oxygen. The oxygen cone can achieve an oxygen dissolution efficiency of over 90% by thoroughly mixing pure oxygen with water, which is much higher than traditional oxygenation equipment. At the same time, oxygen cones can significantly increase the dissolved oxygen concentration in water in a short period of time, making them suitable for high-density aquaculture or emergency oxygenation needs. Oxygen cones are usually vertical conical structures with a small footprint, which can improve land use efficiency. When designing a circular aquaculture workshop, it is necessary to reserve a certain area for the oxygen cone, which can be placed in the open space between large equipment in a timely manner.3. Nano aeration discNano ceramic disc oxygenation is an advanced oxygenation technology in recirculating aquaculture systems, which utilizes aeration discs made of nano ceramic materials to efficiently dissolve oxygen into the water. Compared to traditional oxygenation methods, nano ceramic discs have significant advantages in oxygenation. Firstly, the surface of the nano ceramic disk has a uniform microporous structure, which can generate extremely small bubbles (usually less than 1 millimeter in diameter), greatly increasing the contact area between oxygen and water. Due to the small size and slow rising speed of bubbles, the residence time of oxygen in water is prolonged, and the dissolution efficiency is significantly improved, usually reaching 35% -40%.When designing nano ceramic disks, they can be configured according to the size of the water body. Generally, a nano ceramic disk is designed with 10-15 cubic meters of water. When installing nanoceramic discs, they can be evenly placed at the bottom of the breeding pond. （6） Key points of supporting facility area design1. Distribution room design1) Load calculationCalculate the total power load based on the total power of all electrical equipment in the breeding workshop, and reserve a certain margin to meet the potential increase in equipment power demand in the future. At the same time, the stability and reliability of power supply should be considered, and dual power sources or backup generators can be equipped to ensure that the aquaculture system can operate normally for a period of time in the event of a power outage.2) Layout of power distribution equipmentReasonable layout of distribution cabinets, transformers, cable trays and other distribution equipment should be arranged inside the distribution room. The distribution cabinet should be installed in a dry and well ventilated location for easy operation and maintenance. Cable trays should be laid according to specifications, with strong and weak electricity separated to avoid electromagnetic interference. The floor of the distribution room should be covered with insulated flooring, and the walls and ceiling should be treated with fire protection to ensure electrical safety.2. Control room design1) Monitoring system configurationThe control room is the "brain" of the entire breeding workshop and should be equipped with advanced monitoring systems, including water quality monitors, water temperature sensors, dissolved oxygen meters, video surveillance equipment, etc. The water quality monitor should be able to monitor key indicators such as ammonia nitrogen, nitrite, nitrate, pH value, etc. in the water in real time; The water temperature sensor and dissolved oxygen meter should accurately measure the temperature and dissolved oxygen content of the aquaculture water; Video surveillance equipment should cover important areas such as breeding areas and water treatment areas to facilitate real-time observation of breeding conditions and equipment operation status by staff.2) Control system designEstablish an automated control system to achieve remote control and automatic adjustment of various equipment in the breeding workshop. For example, automatically adjusting the operating power of the fan or oxygen generator based on the dissolved oxygen content of the aquaculture water; Automatically turn on or off the heating device according to changes in water temperature; Automatically control the operation time and dosage of water treatment equipment based on water quality indicators. The control system should have data storage and analysis functions, be able to record various parameter changes during the breeding process, and provide data support and decision-making basis for breeding management.3. Design points for feed storage room and drug storage room1) Feed storage roomThe feed storage room should be kept dry, ventilated, and cool. The floor should be treated with moisture-proof measures, such as laying moisture-proof mats or using moisture-proof materials. Feed should be stored by category, and different varieties and specifications of feed should be stacked separately and clearly labeled. Temperature and humidity meters should be equipped in the storage room to regularly monitor the environmental temperature and humidity, ensuring that the quality of feed is not affected. The stacking height of feed should be moderate to avoid excessive pressure and spoilage of the bottom feed.2) Drug storage roomThe drug storage room should comply with relevant safety regulations, set up dedicated drug cabinets or shelves, and store drugs by category. Disinfectants, insecticides, antibiotics, etc. should be stored separately and clearly labeled with drug names, specifications, expiration dates, and other information. The drug storage room should be equipped with ventilation equipment, fire-fighting equipment, etc. to ensure environmental safety. At the same time, a drug inventory registration system should be established to record in detail the procurement, use, and inventory of drugs for easy management and traceability. （7） Design points of ventilation and temperature control system1. Ventilation system1) Ventilation method selectionAccording to the scale and structure of the breeding workshop, a combination of natural ventilation and mechanical ventilation can be used. Natural ventilation is mainly achieved through skylights on the top of the workshop and ventilation windows on the side walls. When weather conditions permit, natural wind should be used as much as possible for ventilation and air exchange. Mechanical ventilation involves installing exhaust fans, axial fans, and other equipment to force air flow, expel polluted air from the workshop, and introduce fresh air. 2) Ventilation Calculation and Equipment SelectionCalculate the required ventilation based on factors such as breeding density, water evaporation, and equipment heat dissipation in the breeding workshop. Generally speaking, the ventilation required per kilogram of fish per hour is 0.1-0.3 cubic meters. Based on the calculated ventilation volume, select ventilation equipment with appropriate power and air volume, and arrange ventilation openings and ducts reasonably to ensure uniform air circulation and no dead corners in the workshop.2. Temperature control systemFor varieties that require winter heating for breeding, suitable heating equipment such as boilers, heat pumps, electric heaters, etc. should be selected. The boiler has high heating efficiency, but requires specialized boiler rooms and chimneys, resulting in high operating costs; Heat pumps have good energy-saving effects, but require a large initial investment; Electric heaters are easy to install, but their operating costs are also relatively high. Select heating equipment based on factors such as breeding scale, energy supply conditions, and economic costs. The installation position of heating equipment should be reasonable to ensure that hot water can be evenly delivered to each breeding pool. Heating efficiency and energy utilization can be improved by installing hot water circulation pumps and pipeline insulation measures.（8） Design of Circulating Water Pipeline SystemThe circulating water pipeline system should include the inflow, outflow, drainage, oxygenation, and replenishment of the aquaculture pond. The "blood vessels" of high-density circulating aquaculture systems through pipelines. If the pipeline layout is improper or the design is incorrect, it will expose aquaculture products to multiple risks. The pipeline layout needs to fully consider factors such as the location, size, quantity of aquaculture ponds, and the location of water treatment areas. Through scientific and rational layout planning, it is possible to ensure that aquaculture water can be evenly and quickly transported to various aquaculture ponds, while also facilitating the timely transportation of waste and water with abnormal water quality back to the treatment area for treatment. The circulating water pipeline system should be installed in the pipeline ditch, and sufficient maintenance and operation space should be left for each layer of pipeline. Labels can be affixed to pipelines and other areas that require identification, with identification symbols consisting of characteristic names, flow directions, and main process parameters.1. Composition of pipeline system:1) Inlet pipelineThe inlet pipe is responsible for sending the treated water back to the breeding pond. The inlet main pipe usually uses PP or PVC pipes with a diameter of 200mm to 315mm, and the inlet pipe diameter is 75mm to 110mm, controlled by valves to control the inlet flow rate.2) Return water pipelineThe return water pipeline is responsible for sending the water from the breeding pond back to the treatment system. The return water pipeline is usually set in the pipeline trench, and PVC water supply pipes with a diameter of 160mm to 400mm are commonly used.3) Drainage pipelineUsed for emptying water from aquaculture ponds, discharging pollutants from vertical flow sedimentation devices, and backwashing pollutants from microfiltrations. PVC pipes with a diameter of 200mm to 250mm are commonly used for drainage pipelines. One end is connected to an outdoor sedimentation tank, and the other end is equipped with a high-pressure water pump for regular flushing of accumulated dirt in the pipeline.4) Oxygenation pipelineUsed to provide oxygen to the breeding pool. The oxygenation pipeline system is divided into two parts: one is to place nano ceramic oxygenation disks in the breeding pool, and connect the gas flow meter regulating system outside the pool through high-pressure PU pipes; The second method is to mix oxygen and water thoroughly through a pure oxygen mixer, and then enter the breeding pool through a separate PVC pipeline.5) Water replenishment pipelineThe water replenishment pipeline should be connected to the storage tank of the circulating water system. Water replenishment pipelines are usually made of corrosion-resistant materials such as PVC or PP pipes to ensure long-term stable operation of the pipeline. Pipes with diameters ranging from 32mm to 75mm are commonly used. Electric regulating valves and water level sensors can be installed on the water replenishment pipeline to monitor the water level of the breeding pool or storage tank in real time through the water level sensor. When the water level is lower than the set value, the electric regulating valve automatically opens to replenish water; When the water level reaches the set value, the electric regulating valve automatically closes.2. Principles of pipeline layout1) Reduce resistanceThe pipeline layout should minimize the number of bends and joints to reduce head loss and ensure smooth water flow.2) Reasonable directionPipelines should be placed in dedicated pipeline trenches as much as possible to protect them from external environmental influences. The direction of the pipeline should be as simple and reasonable as possible, avoiding crossing.3) Easy to maintainEach layer of pipeline should leave sufficient space for maintenance and operation, facilitating daily maintenance and repair.In order to ensure the stable operation of the system in case of emergencies, pipeline design also needs to consider emergency measures. For example, in emergency situations such as power outages, equipment such as backup generators and emergency oxygenation devices can be used to ensure that the aquaculture water can continue to circulate and avoid deterioration of water quality that could harm the aquaculture organisms.3. Pipeline layout diagramPipeline design is crucial, and specialized pipeline design drawings need to be drawn.(9) How to optimize workshop design to reduce heating energy consumption1. In terms of structural design1) Material selection for walls and roofsUse building materials with good thermal insulation performance, such as polyurethane foam, rock wool, etc., to build walls and roofs of workshops. For the roof, a triangular apex or arch structure can be used, and covered with materials such as asbestos tiles and fiberglass tiles.2) Set up insulation layerInstall insulation layers inside the walls, floors, and roofs of the workshop to reduce heat loss. The thickness of the insulation layer should be determined according to the local climate conditions and insulation requirements3) Sealing designEnsure good sealing of doors, windows, ventilation openings, and other parts of the workshop to prevent cold air from entering and heat loss. Sealing strips can be installed or sealant can be used for sealing treatment2. Equipment selection and layout1) Choose efficient and energy-saving heating equipmentThe use of efficient and energy-saving heating equipment such as heat pumps can effectively reduce energy consumption and operating costs. Heat pumps can heat aquaculture water by absorbing heat from the environment, and have a high energy efficiency ratio.2) Use insulation fabric or insulation filmSetting up insulation curtains or films in the workshop can further prevent heat loss. For example, installing a rolling shutter and insulation curtain on the top of a transparent shed.Through the comprehensive application of the above measures, the insulation effect of the circular water aquaculture workshop can be effectively improved, energy consumption and production costs can be reduced, and the aquaculture efficiency can be improved. 

Process DesignLand-based Industrialized Recirculating Aquaculture System (RAS) (RAS)Land-based Industrialized Recirculating Aquaculture System (RAS) (RAS) employs modern industrial technologies—including engineering, biotechnology, mechanical equipment, information systems, and scientific management—to comprehensively control the aquaculture process. It creates optimal environmental conditions for aquatic organisms, enabling year-round high-density, high-efficiency, and healthy production, and represents a pivotal direction for the future of aquaculture. Design WorkflowThe design of Recirculating Aquaculture System (RAS) water treatment processes is based on material balance principles, with the core objective of rapidly removing harmful substances (e.g., suspended solids, ammonia nitrogen). Balance equations for these pollutants are established to derive system parameters, which are then refined using engineering practical experience to enhance model reliability.Key design parameters depend on: Cultured species and Maximum Biomass Carrying Capacity ( Biomass Carrying Capacity=Density×Effective Water Volume ) From this, daily feed input and total waste (solid particles, ammonia nitrogen) are calculated. These values determine equipment specifications (e.g., biofilter size, bio-media volume, microscreen filter capacity). Step-by-Step WorkflowStep 1: Determine Aquaculture Water VolumeThe water volume should be determined based on land availability, financial capacity, and operational scalability.Step 2: Select Aquaculture SpeciesSpecies selection must consider: Water quality compatibility, Farming complexity, Growth cycle, Market demand, Economic viability.Step 3: Define Stocking Density & Maximum Daily Feed InputCalculate a reasonable breeding density based on the selected breeding species and the size of the breeding water body, and use this to calculate the maximum daily feeding amount.Step 4: Quantify Maximum Waste ProductionThe core of the design of industrialized circulating water treatment process is how to quickly remove the breeding waste generated after feeding. In other words, before feeding, all water indicators in the aquaculture pond are balanced and meet the standards. But after injecting a large amount of feed, the balance of the breeding pond will be disrupted, and a large amount of solid, liquid, and gaseous waste will be generated.Step 5: Design Water Treatment EquipmentCalculate the performance parameters of water treatment equipment based on the maximum total amount of waste.Reference Process ParametersReference Process ParametersMaximum number of cycles for the circulating water system24 cycles/dayBreeding densitySeawater (e.g., Grouper): ≥50 kg/m³Freshwater (e.g., Bass): ≥50 kg/m³Utilization rate of aquaculture water in the circulating water system≥90%Water exchange rate≤10%UV sterilization rate≥99.9%Special Operational ModesIn addition to the normal aquaculture mode, the following normal factors should also be considered during the process of Recirculating Aquaculture System (RAS) System (RAS).1. Power outage emergency modePower outages during the aquaculture process can cause fatal losses to the circulating water aquaculture system, so it is necessary to have a power outage emergency mode in the design to prevent power outages from occurring. 1) Install backup generator: Quickly start the generator in case of power outage to ensure the normal operation of the circulating water system. 2) Design overflow pipeline: When the circulating pump is powered off and not working, the overflow pipeline can promptly drain the water in the pump pool to prevent water from overflowing the pump pool. 3) Equipped with emergency oxygenation: farmed animals may die quickly under low dissolved oxygen conditions. The liquid oxygen system does not rely on electricity and can continuously supply oxygen to the breeding pool in the event of a power outage, ensuring the short-term health of the breeding animals.Disinfection ModeRelying solely on physical sterilization to disinfect the water is not enough if the breeding animals develop diseases during the breeding process. At this time, some chemicals may be used for disinfection and sterilization. The residue of chemical drugs is likely to enter the biochemical filter through water circulation. The nitrifying bacteria in the biochemical filter are very fragile. The influx of chemicals is likely to kill nitrifying bacteria on a large scale. Therefore, when designing a Recirculating Aquaculture System (RAS) system, there must be a separate disinfection mode. When chemical disinfection is required, ensure that the circulating water does not flow through the biochemical filter.Idle ModeIn humid environments, metal components of valves (such as valve stems, valve cores, etc.) are prone to chemical reactions with oxygen and moisture in the air, resulting in rust formation. During the breeding process, valves often rotate, and rust is removed by friction between components. However, long-term maintenance will accumulate a large amount of rust between valve components, increase the friction between valve components, and make it difficult for the valve to rotate or even open. In view of this, in the maintenance mode, all valves will be opened once a day to avoid valve failures caused by prolonged disuse. Given the above special mode, if it is considered that the operation is relatively complex, it will cause unnecessary losses if workers make mistakes. Bang Bang has launched a smart control system for circulating water, which can switch between different operating modes according to different scenarios.

RAS system design process

Understanding RAS AquacultureDefinition and Key CharacteristicsRAS is a closed system where water is continuously filtered and recycled, creating an enclosed environment for fish farming. This method eliminates the need for large bodies of water and allows farms to be located on land, reducing the impact on coastal environments. RAS systems are characterized by their ability to manage water quality, enhance fish health, and minimize environmental and operational impacts.Benefits and ChallengesBenefits:- Flexibility: RAS can be located closer to consumer markets, reducing transportation costs and carbon footprint.- Sustainability: Closed systems significantly reduce water usage, waste generation, and the risk of disease transmission to wild fish populations.- Climate Resilience: RAS can operate year-round with controlled environmental conditions, making them less susceptible to climatic variations.Challenges:- High Capital Costs: Initial setup and maintenance can be expensive.- Energy Intensive: Continuous water filtration and recirculation require significant energy consumption.- Technical Expertise: Requires specialized knowledge and management to ensure optimal system performance.Regulatory Framework OverviewThe regulatory framework for aquaculture is designed to ensure sustainable practices, prevent environmental harm, and protect public health. Both international and national bodies play crucial roles in establishing and enforcing these regulations.Compliance with Environmental RegulationsNutrient Management and Waste ControlRAS systems generate minimal waste due to their closed-loop design. Proper nutrient management is crucial. Operators must ensure that waste is properly treated and disposed of to avoid environmental contamination. This includes implementing a controlled water flow system, using efficient filtration processes, and regularly monitoring nutrient levels.Water Quality Standards and MonitoringWater quality in RAS systems is continuously monitored to maintain optimal conditions for fish health. Parameters such as dissolved oxygen, pH, temperature, and ammonia levels are regularly checked. Authorities may require operators to submit detailed water quality reports and conduct on-site inspections to ensure compliance.Biodiversity and Habitat PreservationProtecting local biodiversity is a key concern. RAS operations must avoid introducing invasive species and minimize impacts on native ecosystems. Operators are often required to undertake environmental impact assessments and implement mitigation measures to preserve local habitats.Health and Safety RegulationsDisease Prevention and ControlControlling diseases in RAS systems is critical due to the enclosed environment and high fish density. Operators must adhere to strict biosecurity protocols, including regular health monitoring and isolation practices. The use of pathogens and antibiotics must be strictly regulated to prevent resistance and environmental contamination.Pathogen and Antibiotic ManagementThe use of antibiotics and other chemicals in RAS systems is tightly controlled. Operators must maintain detailed records of any medications used and ensure they are applied in a responsible manner to protect both fish and human health.Worker Safety and WelfareEnsuring the safety and welfare of workers is paramount. RAS operators must comply with labor laws and provide a safe working environment, including proper training, personal protective equipment, and emergency response protocols.Inspection and Monitoring ProtocolsRegular Inspections by Regulatory BodiesRegular inspections by regulatory agencies are essential to ensure compliance with all applicable regulations. These inspections cover various aspects of operations, from water quality and waste management to biosecurity and worker welfare.Data Logging and Record-KeepingTraceability and Certification ProgramsAchieving and maintaining certification through organizations like the Aquaculture Stewardship Council (ASC) can provide an additional layer of assurance. These programs ensure that operations meet stringent environmental and social standards, enhancing market access and consumer confidence.Successful Implementation of Regulatory FrameworksSuccessful RAS OperationsSeveral RAS operations have successfully implemented rigorous regulatory frameworks. For example, a land-based RAS farm in New Zealand demonstrated compliance by regularly testing water quality, implementing effective biosecurity measures, and maintaining detailed records of all operations. This farm not only met regulatory requirements but also achieved ASC certification, validating its sustainable practices.Lessons Learned and Best PracticesKey lessons from successful RAS operations include:- Proactive Monitoring: Regular and meticulous monitoring of environmental and operational parameters.- Collaboration: Working closely with regulatory bodies and industry experts to stay informed about best practices.- Continuous Improvement: Regularly reviewing and updating regulatory compliance measures to ensure ongoing sustainability.Comparative Analysis: RAS vs. Conventional AquacultureRegulatory Requirements ComparisonRAS Aquaculture:- Nutrient Management: Stricter controls on waste and nutrient management.- Water Quality Monitoring: More frequent and detailed water quality assessments.- Biosecurity: Higher standards for disease prevention and pathogen control.Conventional Aquaculture:- Nutrient Management: Generally less stringent waste management practices.- Water Quality Monitoring: Less frequent and less detailed water quality assessments.- Biosecurity: Lower standards for disease prevention.Pros and Cons of Regulatory CompliancePros:- Environmental Protection: RAS operations that comply with regulations minimize environmental impacts.- Market Access: Compliance enhances market access and consumer trust.- Long-Term Viability: Meeting regulatory requirements ensures long-term sustainability and success.Cons:- Cost: Initial setup and maintenance costs can be high.- Complexity: Strict regulations may require additional resources and expertise.- Technological Dependence: Reliance on advanced technology and specialized management.Future Trends and Emerging StandardsEmerging Technologies and PracticesTechnological advancements in RAS are expected to drive further improvements in efficiency and sustainability. Innovations such as advanced filtration systems, precise environmental control, and real-time data monitoring are likely to become more prevalent.Future Regulatory Trends and ChallengesAs RAS grows in importance, regulatory frameworks will continue to evolve. Future challenges may include:- Technological Adaptation: Keeping up with the rapid pace of technological advancements.- Regulatory Consistency: Ensuring consistent and harmonized standards across different regions.- Public Awareness: Building public trust and understanding of the benefits and challenges of RAS.

In the evolving landscape of aquaculture, Recirculating Aquaculture Systems (RAS) have emerged as a promising solution for sustainable and efficient fish farming. These systems recirculate and filter water, providing a clean and controlled environment for fish. This closed-loop system not only reduces water usage but also minimizes the environmental impact of traditional practices. However, the implementation of RAS systems comes with significant costs, both in the initial setup and ongoing operations. Understanding these costs is crucial for anyone considering this innovative approach to aquaculture.Initial Investment CostsThe initial investment in RAS systems can be substantial due to the high capital expenses required for infrastructure and equipment. Key components of RAS systems include:- Infrastructure: This includes the construction of tanks, filtration systems, and other structural elements. Building sturdy and durable tanks that can withstand the pressure and rigors of RAS operations is a significant cost.- Water Treatment Systems: RAS systems require sophisticated water treatment equipment to maintain water quality, including biofilters, mechanical filters, and UV sterilizers. These systems are essential for removing waste products and ensuring a healthy environment for the fish.- Filtration and Aeration Equipment: Effective filtration and aeration are critical for maintaining oxygen levels and removing waste. High-quality pumps, filters, and aeration units are necessary to sustain a healthy aquatic environment.Operational and Maintenance CostsOnce the RAS system is up and running, operational and maintenance costs continue to be a significant factor in the long-term success of the business. These costs include:- Electricity: RAS systems are energy-intensive, with pumps, heaters, and filtration equipment consuming a considerable amount of electricity. The cost of electricity can significantly impact the overall operational budget.- Chemicals: Regularly adding chemicals such as disinfectants, pH adjusters, and water softeners is necessary to keep the water chemistry within safe limits. These chemicals can be expensive and must be used judiciously.- Labor: Maintaining the RAS system requires skilled labor for regular checks, maintenance, and interventions. Skilled personnel are essential for ensuring the system operates smoothly and efficiently.Energy Consumption and EfficiencyEnergy efficiency is a critical aspect of RAS system design and operation. While RAS systems are efficient in terms of water usage, they can be quite energy-intensive. The costs associated with energy consumption include:- Pump Costs: High-efficiency pumps are crucial for maintaining water circulation and aeration. The cost of high-quality pumps can be significant, but they offer better long-term savings through reduced energy consumption.- Heating/cooling Costs: Maintaining the optimal temperature for fish can require significant energy. Efficient heating and cooling systems are essential to keep costs under control.Feasibility Studies and Risk ManagementConducting thorough feasibility studies and risk management strategies are essential steps in the planning phase of an RAS project. The costs associated with these activities include:- Feasibility Studies: Hiring experts to conduct detailed studies that assess the viability of the project, including market analysis, environmental impact, and financial projections.- Risk Management: Implementing strategies to mitigate financial and operational risks, such as insurance, contingency plans, and regular system audits.Comparative Analysis of RAS and Traditional AquacultureWhen comparing RAS systems to traditional aquaculture methods, its important to consider both capital and operational costs. Key factors to consider include:- Capital Costs: RAS systems often require a higher initial investment due to the specialized equipment and infrastructure. However, they also offer long-term savings through reduced water usage and lower disease transmission.- Operational Costs: While RAS systems are more expensive to run due to higher energy and maintenance costs, they provide a more controlled environment that can lead to higher yields and reduced disease outbreaks. Traditional methods, while less costly to operate, can be more susceptible to environmental factors and disease.Long-term Economic ViabilityAnalyzing the long-term economic viability of RAS systems involves assessing the return on investment (ROI) and comparing it to traditional aquaculture methods. Key considerations include:- Examining successful RAS projects and their cost benefits can provide valuable insights. For example, a study might show that an RAS project has a higher ROI due to increased yield and reduced operational costs over time.- Sustainability: RAS systems are more sustainable and environmentally friendly, which can translate into long-term benefits, including better market access and regulatory compliance.SummaryImplementing RAS recirculating aquaculture systems comes with a set of significant costs, including initial investments, operational expenses, and energy consumption. However, these costs can be outweighed by the benefits of sustainability, efficiency, and long-term economic viability. By understanding and managing these costs effectively, aquaculturists can ensure the success and profitability of their RAS projects.In the future, advancements in technology and ongoing research will likely reduce the costs associated with RAS systems, making them even more viable for widespread adoption. As the world increasingly turns towards sustainable and efficient farming practices, RAS systems are likely to play a crucial role in shaping the future of aquaculture.