Recirculation Aquaculture System

RAS are used in home aquarium and for fish production where water exchange is limited and the use of biofiltration is required to reduce ammonia toxicity. other types of filtration and environmental control are often also necessary to maintain clean water and provide a suitable habitat for fish. the main benefit of ras is the ability to reduce the need for fresh, clean water while still maintaining a healthy environment for fish. to be operated economically and commercially, ras must have high fish stocking densities..

Ability to closely monitor and control environmental conditions to maximize production efficiency. Similarly, independence from weather and variable environmental conditions. Reduced water requirements as compared to raceway or pond aquaculture systems. Site selection flexibility and independence from a large, clean water source. Reduced land needs due to the high stocking density.

High operating costs mostly due to electricity and system maintenance. High upfront investment in materials and infrastructure.

RAS Water Treatment Processes

A series of treatment processes are utilized to maintain water quality in intensive fish farming operations. These steps are often done in series or sometimes in parallel. After leaving the vessel holding fish, water is first treated for solids before entering a biofilter to convert Ammonia. Next degassing and oxygenation occur, often followed by heating/cooling and sterilization. Each of these processes can be completed by using a variety of different methods and equipment, regardless all must take place to ensure a healthy environment that maximizes fish growth and health. Key systems of an RAS are:

Disadvantages

High operating costs mostly due to electricity and system maintenance. High upfront investment in materials and infrastructure.