Temperature impact on nitrification and bacterial growth kinetics in acclimating recirculating aquaculture systems biofilters
Doctor of Philosophy (PhD)
Engineering Science (Interdepartmental Program)
This project assessed short-term temperature effects on total ammonia nitrogen (TAN) utilization rates in a batch laboratory-scale recirculating system. The tank system was designed for experiments on short term steady state and diurnal temperatures. A set of numerical models was developed to simulate observed results. The performance of the biofilters was determined with three tank replicates at fixed temperatures of 13, 20 and 300C; and at diurnal transient (sinusoidal) temperature regimes of (20 ± 30C; 30 ± 30C). Ammonia utilization rates and biofilter performance for beads acclimated at different temperatures regimes separated and mixed were also determined. Total ammonia utilization rates increased with increased temperatures. The ammonia removal rates (Pseudo Zero Order) with slope (K) did not significantly differ (P > 0.05) for 130C (K = -0.02) and 200 C (K = -0.04); but differed (P < 0.05) for 13 and 300C (K = -0.12) and also differed (P<0.05) for 200C and 300C. Diurnal temperatures values differed (P = 0.001) for 200C ± 30C (K = -0.08) and 300C ± 30C (K = -0.19). Ammonia utilization rate values for beads that were acclimated and mixed at temperatures of 13, 20, 300C and subjected to diurnal temperatures differed (P = 0.024) at 200C ± 30C (K = -0.12); and 300C ± 30C (K = -0.36). Biofilter performance increased with temperature linearly with increased performance occurring at higher temperatures and high bacterial mass. Ammonia utilization rate simulated models matched the observed data and assisted in determination of bacterial mass. Future designs and acclimation of the bead filters may be further enhanced by decreasing biofilter acclimation periods using higher temperatures in recirculating systems.
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Saidu, Milton Maada-Gomoh, "Temperature impact on nitrification and bacterial growth kinetics in acclimating recirculating aquaculture systems biofilters" (2009). LSU Doctoral Dissertations. 37.