• Energy efficiency, using less and reusing energy where possible. Reducing pumping head and improving the biofilter’s performance for instance, means less energy will be needed (Jokumsen and Svendsen, 2010).
• Recovering wash water from the drum filter backwashing e.g. using flocculants (currently under investigation) will reduce the amount of intake water, decreasing environmental impact and reducing pumping costs.
• Introduction of new compartments such as algal and for aquaponics production to (I) decrease environmental output, (II) valorize nutrients and detritivores taking advantage of produced byproducts such as carbon dioxide and (III) generate secondly products to a major economical input.
• The implementation of a “hybrid technology of biofloc technology (BFT) and RAS” as Azim and Little (2008) suggested. A more recent study showed that BFT could help environmental and economic sustainability of RAS by reducing the feed cost (Kuhn et al., 2009).