Author
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Brazil, Brian |
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Submitted to: Aquaculture Magazine
Publication Type: Popular Publication Publication Acceptance Date: 2/10/2006 Publication Date: 5/1/2006 Citation: Brazil, B.L. 2006. Performance of a rotating biological contractor in tilapia recirculating aquaculture system. Aquaculture Magazine, 32(3) 52-59. Interpretive Summary: Technical Abstract: This paper describes the performance characteristics of an industrial-scale air-driven rotating biological contactor (RBC) installed in a recirculating aquaculture system (RAS) rearing tilapia at 28 oC. This 3-staged RBC system was configured with stages 1 and 2 possessing approximately the same total surface area and stage 3 approximately 25% smaller, providing a total surface area of 13,380 m2. Ammonia removal efficiency averaged 31.5% per pass for all systems examined, which equated to an average (+ standard deviation) total ammonia nitrogen (TAN) areal removal rate of 0.43 + 0.16 g/m2/day. First-order ammonia removal rate (K1) constants for stages 1, 2, and 3 were 2.4, 1.5, and 3.0 /hr, respectively. The nitrite first-order rate constants (K2) were higher, averaging 16.2/hr for stage 1, 7.7/hr for stage 2, and 9.0/hr stage 3. Dissolved organic carbon (DOC) constituents were not readily removed; DOC levels decreased an averaged 6.6% per pass across the RBC. Concurrently, increasing influent DOC concentrations decreased ammonia removal efficiency. With respect to dissolved gas conditioning, the RBC system reduced carbon dioxide concentrations approximately 39% as the water flowed through the vessel. The cumulative feed burden --describes the mass of food delivered to the system per unit volume of freshwater added to the system daily -- ranged between 5.5 and 7.3 kg of feed per m3 of freshwater; however, there was no detectable relationship between the feed loading rate and ammonia oxidation performance. |
