|MALONE, RON - LSU
Submitted to: Journal of Aquaculture Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/1/2005
Publication Date: 1/2/2006
Citation: Pfeiffer, T.J., Malone, R. 2006. To rating fixed-film biofilters used in recirculating aquaculture systems. Journal of Aquaculture Engineering. 34(1):1-14.
Interpretive Summary: Predicting the performance of biofilters is an engineering challenge that is critical to both designers and managers. The task is complicated by the wide variety of water quality expectations and environmental conditions displayed by a recirculating aquaculture system (RAS). As a foundation, a proposed RAS classification system based upon salinity, temperature, and trophic levels is used to create 17 systems classifications. An experimental methodology based upon chemical feeds is proposed to represent steady state RAS performance of the biofilters. Data is summarized by linear analysis of filter performance for concentration ranges below 1.0 mg/L TAN and simple averaging is proposed for higher trophic levels. Input from the the aquacultural engineering community and RAS aquaculturists is required to further refine the approach prior to endorsement.
Technical Abstract: A standardized methodology for evaluating and rating biofilters is proposed to simplify design of recirculating systems. This methodology will allow engineers to compare biofilters options and accurately predict performance before construction. The methodology is based upon an increasing recognized classification of recirculating systems that combines thermal, salinity, and trophic levels to establish a recirculating system classifications. Each trophic level is linked to a table of expected water quality values that is consistent with typical uses. Direct measure of filter performance under defined conditions is employed, avoiding disputes of practice and theory that could undermine the rating system. Central to the rating system is the volumetric total ammonia nitrogen (TAN) conversion rate (VTR). This term relates the TAN conversion (g TAN per m3 of filter media per day) to the bioreactor’s size. The parameter can be directly measured and used to rate a filter’s performance under different culture conditions. Tabulation of the rating numbers would form an information base to allow users to estimate the capabilities of different biofilters for their intended application. The rating process can then be advanced by linkage with kinetic relationships used with computer models employed to design sophisticated recirculating systems.