Aquaculture production in RAS is in general considered sustainable as external water usage is small compared to conventional fish farming. However, RAS can still exert a considerable environmental impact as concentrations of organic matter and nutrients (especially inorganic nitrogen and phosphorus) in their effluents are high. Reduced environmental impact can either be accomplished by proper post-treatment of the effluents or by or by more efficient water treatment within the RAS. One can then achieve what is termed Zero Discharge. 

Zero discharge, though it will never be 0%, will have some indirect cost savings in heat/cooling, costs of waste disposal, reduction in make-up water requirements and cost of make-up water treatment to mention some.

IAA has total solution for zero discharge systems.