| The objective of this study was to determine the potential of using a recirculating raceway system to remove phosphorus-containing material from agricultural wastewater streams. The focus of the research was on the biological and physical characteristics of Corbicula populations and monitoring of various water quality parameters within the system, with special emphasis on phosphorus dynamics. A prototype raceway system was designed and constructed at the University of Florida Dairy Research Unit at Hague, Florida to test the adaptability and phosphorus removal capacity of the clams in wastewater treatment.;The ability of freshwater clams to capture, sequester and retain phosphorus-containing material from varying amounts of fertilizer additions was demonstrated in this study. Clam biomass contained an average phosphorus concentration of 0.299 mg P/g of whole clam DW (SE = 0.005), similar to other bivalves. Tagged clams recaptured alive over the course of the study showed growth rates of up to 0.117 mm/day in shell length (0.0024 g clam DW/day), yielding phosphorus removal rates up to 0.0079 mg P/individual/day. Overall, raceway clam populations were subject to high mortality and were unable to demonstrate significantly long-term removal of total phosphorus, dissolved phosphorus or chlorophyll a from overlying source water. High temperatures and possible impacts from amphipod infestations may have affected clam populations.;Even though some clams in this study did survive and grow, use of Corbicula culture for phosphorus treatment in Florida agriculture operations may require creative solutions to temperature and parasite problems. Despite these issues, the raceway-based recirculation system design demonstrated in this study provided a dependable, easy to construct and reusable platform for testing aquaculture potential of a variety of organisms in wastewater treatment conditions at large scale. The ultimate goal of this study was to provide an effective biological remediation mechanism for removal of phosphorus from dairy waste streams; however, toxicity of dairy effluent, even at high dilutions, may prohibit application of clam-based aquaculture systems without additional treatment mechanisms. |
