TABLE OF CONTENTS Pages Symposium 1 - the National Sea ...

Effects of Baffle Depth on Oxygenation at the Pumping
Station of Intensive Bioproduction
Korean (IBK) Recirculating Aquaculture System
Introduction
Jae-Yoon Jo
Professor of Aquaculture, Department of Aquaculture
Pukyong National University, Pusan 608-737, Korea
In-Bae Kim
Professor Emeritus
Pukyong National University
Pusan 608-737 Korea
Jin Hwan Lee
Graduate Student
Department of Aquaculture
Pukyong National University
Pusan, 608-737 Korea
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Jeonghwan Park
Graduate Student
Pukyong National University
Pusan 608-737, Korea
Kuen-Hack Suh
Professor of Chemical Engineering
Department of Chemical Engineering,
Pukyong National University
Pusan, 608-707 Korea
Dissolved oxygen is one of the most important water quality parameters for
aquaculture and maintaining proper concentration in a high density recirculating
aquaculture system is always important for both fish and nitrifiers. Therefore a variety of
aeration devices are employed or pure oxygen is applied in the culture system. But extra
energy or cost is needed to operate the aeration devices or to supply the pure oxygen.
Their efficiency is varying but all devices have to add up to the production costs. It is
known that cost of oxygen supply is highest in the total expenditure of aquaculture except
for feed cost. The percentage of aeration cost to the total expenditure in rainbow trout
culture, hatchery, and recirculating aquaculture was 13-15%, 23% (Petit 1990), and
8.6%(Timmons and Aho 1998), respectively. Therefore proper devices have to be
selected for the reduction of production cost. In the Intensive Bioproduction Korean
(IBK) recirculating aquaculture system, circulating pump(s) also supplies oxygen into
water while circulating the water. Since a lot of bubbles are formed in the pumping
process, oxygen is easily transferred to the water. The efficiency of oxygen transfer ratio
(OTR) is positively related with contact time between bubbles and water but is negatively
related with bubble size. Water temperature also affects the saturation point of oxygen.
Therefore, OTR and aeration effectiveness (AE) were compared with the combinations of
two different water temperatures (20 o C and 30 o C) and 4 different baffle depths (0, 50,
100, and 150 cm) at the IBK recirculating aquaculture system to check the effect of
temperatures and baffle depths on OTR and AE. .