|RILEY, KENNETH - HBOI
Submitted to: Proceeding of World Aquaculture Society
Publication Type: Abstract Only
Publication Acceptance Date: 1/1/2004
Publication Date: 3/1/2004
Citation: Pfeiffer, T.J., Riley, K. 2004. Evaluation of a small-scale recirculating aquaculture system using a floating bead bioclarifier and fluidized bed biological reactor for warm-water fish culture [abstract]. In: Proceeding of World Aquaculture Society. p. 468.
Technical Abstract: The production strategy of any aquaculture operation is to produce the optimal quantity of a proper sized animal in the shortest period of time by efficient husbandry and stock manipulation. Recirculating aquaculture production systems (RAS) maximize fish production at a competitive cost without the use of extensive natural resources such as land, energy and water. The objective is to maximize the production of tilapia in a basic RAS unit without the use of supplemental oxygenation. The recirculation system consists of a wastewater sump, solids removal devices, a biological filtration unit, and water movement and distribution mechanisms. The culture units are two 3.65-m diameter panel fiberglass circular tanks with a sloping bottom. Culture volume for each tank at 1.0 m depth is approximately 10,500 L. Tilapia are produced through a two-phase system with 3000 1-g fish stocked into the first culture unit and 400 400-g fish stocked into the second culture unit. Solids removal is accomplished using a swirl separator to capture the low-volume, high solids effluent from the center bottom drain of each tank. Flow from the swirl separator joins the high volume flow from the elevated sidewall drain of each tank in a baffled wastewater sump of approximately 1000 L. Water from the sump is pumped (378 L/min) through a 0.28-m3 prop-washed bead filter (PWBF) for additionally solids removal prior to the fluidized sand bed. Backwashing of the bead filter is automated. A fluidized bed biological filter (FBB) filled with 1350 kg of silica sand media is used for biofiltration. After treatment through the PWBF and FBB, water is returned to the culture tanks by gravity flow. In an attempt to determine the performance this basic setup, the behavior and metabolism of the PWBF and FBB is measured as feed demands increase with fish growth. The behavior of the PWBF as a function of solids removal and backwashing requirements as well as the oxygen consumption across the PWBF will be monitored. To measure the performance of the FBB, oxygen and ammonia at the input and output of the filter are measured to determine ammonia removal and oxygen consumption rates with an increasing feed load. Additional parameters being measured include makeup water volume, energy utilization, and daily water quality variables including temperature, pH, and dissolved oxygen.