Niri RAS technology brings together
innovation, simplicity and cost
effectiveness to create a leading
production concept

The Niri RAS technology has been gradually developed over the past 10 years. Arve Gravdal performed his first trial in 2002 (patent no. 10491593 in the US) in 600 m3 tanks. Smolt was reared to adult salmon of 2,8 kg in these tests. After the formal establishment of Niri AS the company has developed the technologies further through a test project in Ireland, and subsequently in Scotland. The goal has been to lower production costs while achieving a high degree of dependability in the operation of the technologies.

In general, the RAS system includes tanks to culture fish, propellers to maintain water flow and systems for water treatment. Water quality is monitored regularly for temperature, dissolved oxygen, carbon dioxide, pH, ammonia, nitrite and solids. Full control of the environment allows higher fish densities than sea cages. Sea based production operates at 25 Kg/m3. Scientific test production in RAS systems has lead to biomass density forecasts as high as 100 Kg/m3 for RAS culture of salmon. However, Niri considers that such high densities are not desirable until there is a solid base of experience to show that it is defensible from a fish welfare point of view. Currently, Niri is basing its capacity- and feasibility assessments on much lower densities. Our approach is to use innovative technology and operations to reduce investment- and operating costs, so that investment decisions can be reached without pushing assumptions regarding biomass density beyond wide safety margins. In this way, investors are set to gain increasing returns on investments as technology, operating procedures and control systems are continually refined, and thus raises the average biomass density, as the operators acquire more experience through practical management of large scale operations.

RAS Technology

The Niri RAS system differs from most other land-based fish farms in that the recirculating process is integrated in each individual tank. The tanks are independent of each other, providing a flexible scaling model while significantly reducing the risk of disease outbreak. The RAS recirculating process makes it easy to control water temperature, oxygen levels, CO2 removal, cost efficient feeding and more.

The Niri RAS technologies are easy to operate and the investment cost has been significantly reduced through research over several years. The result is an aquaculture system with a high degree of dependability, cost efficiency and with optimal conditions for salmon and other fish species.

Sample production facility

Niri monitoring systems