Alternative Solids Removal for Warm Water Recirculating Raft Aquaponic Systems

Aquaponics is an integrated fish and plant recirculating production system. The University of the Virgin Islands' raft aquaponic system uses a cylindro-conical clarifier as a primary solids removal device; however, a swirl separator may offer advantages. The objectives of the 8-wk experiment were to compare water quality parameters, Nile tilapia, Oreochromis niloticus, production and water spinach, Ipomoea aquatica, production in a raft aquaponic system using a clarifier or swirl separator for primary treatment of solids in the waste stream. No significant differences (P0.05) existed between treatments for temperature, oxygen, pH, total suspended solids, alkalinity, electrical conductivity, total ammonia-nitrogen, nitrite-nitrogen, nitrate-nitrogen, macronutrients, and micronutrients concentrations in the culture water. There were no significant differences (P0.05) between treatments for Nile tilapia production, average weight, survival, or feed conversion ratio. There were no significant differences (P0.05) between treatments for water spinach production or plant tissue analysis. In conclusion, the swirl separator used in this experiment performed similar to the clarifier and water spinach grew vigorously in the raft aquaponic system.