Almost all new land-based fish farms constructed in Norway today are recirculating aquaculture systems (RAS), and in addition, many flow through systems are being converted to RAS. Recirculation significantly reduces water demand, increases water quality control, allows for rapid growth at year-round stable temperatures, facilitates utilization of waste, facilitates a good bacterial environment, and provides a basis for more controlled and predictable production both in freshwater and seawater.
The course will provide a broad introduction to RAS and how water treatment can help to create a stable and optimal water environment in the system. Design, dimensioning, start-up, operation, waste management, resource utilization, risk assessment and action plans will be addressed. The subject will hold an interdisciplinary profile, where the technological function and the importance of biological, chemical and physical factors are seen in connection to each other. The course will cover both RAS in freshwater and seawater, for the production of smolt, postmolt, marine fry and marine ongrowing, as well as other relevant species for production in RAS in Norway. The course will also provide insight into how the needs of selected technology and treatment methods change according to the species and life stage.
Recommended previous knowledge
Basic knowledge of aquatic biology, aquaculture and water treatment technology is an advantage.
- The student should be able to explain the most important biological needs and mechanisms that affect the growth, survival and welfare of the fish in aquaculture, especially in RAS. The student should be able to list the most important water quality variables in RAS, interpret limiting values for the most important water quality variables and assess whether the water quality is acceptable for the production organism.
- The student should be able to list the different types of water treatment required in a recycling plant. The student should be able to design a simple RAS, dimension biofilter and CO2-degasser according to a given feed load and be able to justify the selection of the order of water treatment components. The student should be able to provide an overview of the available technological solutions and the principle of how the water treatment components work, critical factors for functionality and how the water treatment components affect each other. More specifically, the student should be able to explain the function and effect of a drum filter, a protein skimmer, a hydrocyclone, a membrane filter, a fixed bed biofilter, a moving bed biofilter, UV disinfection, disinfection with oxidants and a CO2-degasser.
- The student should be able to explain how a change in pH affects CO2 toxicity, alkalinity, ammonia toxicity, toxicity of aluminum and H2S, as well as the effectiveness of the biofilter and CO2-degasser. The student should be able to propose a good tank design and plan for logistics through the facility in relation to the given culture organism.
- The student should be able to give an overview of the most important factors for starting and operating a RAS. The student should be able to assess where to begin looking for errors if there are any problems with the operation of a RAS. The student should be able to discuss, and propose measures and action plans when water treatment components fail, when the fish shows signs of disease, and when one or more of the most important water quality variables are beyond the limiting values for the cultured organism.
- The student should be able to list different types of sensors and measurement methods to measure the most important water quality variables in RAS. The student should be able to use correct measurement methods and information to assess the need for and effect of various forms of water treatment and actions in the RAS. The student should be able to decide where to measure in the RAS and be able to make a plan for measuring water quality and maintenance of sensors in a RAS.
- The student should be able to provide an overview of how physiochemical and biological factors can threaten the health of the cultured organism in RAS. The student should be able to give examples of how water treatment and design of RAS affects the microbiology of the system. The student should be able to analyze and plan biosecurity into a RAS. The student should be able to explain how the ammonium oxidizing and nitrite oxidizing bacteria contribute in the biofilter and how they compete with the heterotrophic bacteria. The student should also be able to explain how the most important water quality variables affect these bacteria groups and the effectiveness of the biofilter.
- The student should be able to estimate the amount and form (dissolved in water, in gasous or particulate form) of the most important waste streams resulting from a given feed amount in a RAS, and be able to suggest ways for handling or utilizing the waste streams. The student should be able to discuss different alternative options for disposal and utilization of the waste streams from RAS in an economic, practical and environmental perspective. The student should be able to present an example of an aquaponic system and to explain the flows of resources in the aquaponic system. The student should be able to use professional terminology and communicate well with the industry that designs, builds and operates RAS.