Mass balance and energy optimisation in recirculating aquaculture systems (RAS), with focus on diurnal variations in water quality – RAS-EN

Project summary

New expertise is needed in the field of energy efficient aquaculture
systems in general and in recirculating systems especially. The energy
intensive nature of recirculation aquaculture systems (RAS) hampers their
sustainability and cost effectiveness. By means of dynamic simulations using
data collected in existing RAS, this interdisciplinary research project will
study and optimise the energy use of RAS if supplied by locally available
renewable energy forms like wind, wave and solar energy as well as biogas
produced from accumulated sludge from the filter systems while taking
diurnal variations in energy demand into account. There is also limited
information regarding how both the biofilters and aerators function during
diurnal fluctuations of water quality parametres. An understanding of the
diurnal variations and better methods of measuring water quality parameters
will help the fish farmers to run their fish farms better in relation to fish
welfare and fish health. The carbon dioxide excretion from the fish results in
acidification of the water in the rearing units and is comparable to increased
carbon dioxide levels in the sea in the future. Thus, knowledge generated
about this topic can also have important relevance beyond the field of
aquaculture.
Better utilization of waste and residual products is a central part of the
circular economy, and can contribute to increased competitiveness and value
creation in Norway. This project will further raise the research competence
within utilisation of fish sludge to increase biogas production.
Knowledge developed through this interdepartmental cooperation in the field
of energy, ocean and aquaculture engineering is relevant to education and
research at Western Norway University of Applied Sciences. The related
industry will contribute to and profit from this research and the positive
environmental and societal impact expected from the new knowledge.