Submitted to: Caribbean and Latin American Aquaculture
Publication Type: Abstract Only
Publication Acceptance Date: 10/1/2007
Publication Date: 11/6/2007
Citation: Pfeiffer, T.J., Hearn, R.A., Chritina, C.M., Malone, R.F. 2007. Mass transfer coefficients for carbon dioxide and oxygen for a polygeyser biofilter using airlift in an aquaculture reuse system [abstract]. Caribbean and Latin American Aquaculture 2007, November 6-9, 2007, San Juan, Puerto Rico. p.84.
Technical Abstract: Aquaculture is a rapidly growing industry, accounting for over one-third of all direct fisheries consumption. In recirculating aquaculture systems the primary technology being used is energy intensive because water must be moved continuously through the culture and treatment units to remove wastes and replace oxygen. An alternative strategy for moving water in recirculating systems would be the use of air-lift technology to provide water movement which is substantially more energy efficient under low-head conditions than centrifugal pumps. Airlift technology provides other benefits to the recirculating system design strategy including aeration, CO2 degassing, foam fractionation as well lower capital costs, simplicity in design, and decentralized biosecurity considerations. Replicate recirculating aquaculture systems (n=4) consisting of the polygeyser bioclarifier in connection with a 3-m diameter tank (1.2-m depth, volume approximately 7.8 m3) were used to obtained the CO2 and O2 mass transfer coefficients for the system. Open tubing airlift units were constructed for each filter/tank combination and supplied with air by a regenerative blower for recirculating water movement through the filters. Air flow to water flow ratios ranging from 0.5 to 2.0 were used in obtaining the mass transfer coefficients. Current data indicates oxygen mass transfer rates ranging from 0.02 to 0.14 kg O2/hr depending on water flow rates, G:L ratio, and salinity. Additional O2 and CO2 mass transfer coefficients determined for the polygeyser bioclarifier using airlift technology without a feed load is presented in addition to a simplified set of design rules for air-lift operation of low-head airlift filtration devices.