Enhancement of Foam Floatation Efficiency by Dissolved Air Flotation Reactor

Foam fractionation or foam floatation technology has been introduced to remove fine particles in the Recirculation Aquaculture System (RAS). The main objective of this study was to assess the effect of a dissolved air flotation reactor on foam floatation efficiency in a conventional RAS. In this study, two different types of air bubble producers were tested for 30 days: dissolved air flotation reactor was compared to a commercialized air bubble producer in a skimming column. Nitrogen concentrations and particles removal rates were measured every other day during the study. The results showed that average rates of ammonia and nitrite concentration were lower in the system equipped with air flotation skimmer compared to those in the air bubble system (0.39 and 0.35 versus 3.45 and 0.65 mg L^-1, respectively; P 0.05). However, nitrate concentration was not influenced by the foam floatation systems (P 0.05). Nitrogen concentrations were almost similar in the two treatments up to day 15 of the study and then showed higher values for the air bubble system.Total particle collection was significantly higher in the systems containing air flotation skimmer (296.1 versus 276.4; P 0.05), though daily collected particle was almost similar in both systems at the end of the study. In conclusion, dissolved air flotation skimmer was able to remove a larger portion of particles rendering improvement of water quality in RAS.