|Davis, Megan - HBOI|
Submitted to: Book of Abstracts World Aquaculture Society
Publication Type: Abstract Only
Publication Acceptance Date: January 1, 2003
Publication Date: February 18, 2003
Citation: PFEIFFER, T.J., RICHE, M.A., DAVIS, M., FREEMAN, D.W. DESIGN AND EVALUATION OF RECIRCULATING AQUACULTURE SYSTEMS FOR MARINE FINFISH PRODUCTION AT HARBOR BRANCH OCEANOGRAPHIC INSTITUTION. BOOK OF ABSTRACTS WORLD AQUACULTURE SOCIETY. 2003. p.229. Technical Abstract: Recirculating aquaculture systems (RAS) are composed of many components: culture tank, solid removal devices, biofiltration, aeration and degassing units, and water movement and distribution mechanisms. For each component, multiple options are available and the selection must be based on system volume, fish and feed loading rates, and water flow and drainage rates. Two Quonset-hut style greenhouses, each 46.3 m in length and 14.2 m in width, were renovated to include eight intensive recirculating systems. There are two different 4-tank RAS designs, each replicated four times inside the greenhouse. The four culture tanks per RAS unit are 3 m in diameter with a sidewall height of 1.1 m and a five-degree bottom slope towards the center drain. The central bottom drain of each tank provides low-volume, high solids effluent flow into the swirl separators. Flow from each tank solid separator joins the high volume flow from the tank sidewall and total flow from all four tanks pass though a microscreen drum filter with a 60 micron mesh screen. From the drum filter, water gravity flows into a sump reservoir. Water is pumped from the reservoir tank to the biofilters. System 1 biofilters utilize a static pressurized floating-beadbed using two 25 ft3 propeller-washed bead filters. System 2 employs a moving low-head floating-beadbed bioreactor (two at 25 ft3 each) for the biofiltration process. Oxygen enrichment with liquid oxygen and O2 saturation cones are placed after the biofilters of each system thereby transporting oversaturated oxygenated water directly back into the culture tanks. Daily and/or weekly culture water monitoring includes recording pH, oxygen concentration, temperature, flow rates, suspended solids and ammonia concentration. Fish production (kg/m3) and energy usage are also recorded for economic evaluation for obtaining comparative performance studies of low-head and pressurized systems for growing fish at commercial levels.