|LENGER, TODD - VA POLYTECH INSTITUTE
Submitted to: Proceedings of the International Conference on Recirculating Aquaculture
Publication Type: Proceedings
Publication Acceptance Date: 6/1/2002
Publication Date: 7/18/2002
Citation: LENGER, T.A., PFEIFFER, T.J. EVALUATION OF SUPPLEMENTAL SOLIDS REMOVAL EFFECTS ON NITRIFICATION RATES IN FLOATING BEAD FILTERS. PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON RECIRCULATING AQAUACULTURE. 2002. p.418.
Technical Abstract: Floating bead filters utilized in recirculating aquaculture systems perform the dual function of nitrification and clarification. As culture water flows through the bead filter, solids accumulate and encourage the growth of heterotrophic bacteria, which reduce substrate availability for the desired nitrifying autotrophic bacteria. Increasing backflushing frequency can counteract the negative effects of solids accumulation in the filter but it also increases the volume system water required. The effects of solids removing solids prior to bead biofiltration were evaluated. Three 4,000 L tanks were equipped with either a 300 micron, 600 micron, or no micron bag filter prior to recirculating the water through a 56.6 L floating plastic bead filter. The culture tanks were stocked with 70 kg of tilapia fingerlings and fed a 32% protein-floating pellet. The nitrification of each system (grams total ammonia removed per m3 of media per day) at three feed loading rates, 450, 675, and 900 g/day. During each evaluation period, water samples were collected at 0, 6, 12, and 24 hours after backflushing. Overall results indicated greater nitrification rates at the higher feeding rates and with greater solids removal.