Optimization of yield and biofiltering efficiencies of Ulva rigida C. Ag. cultivated with Sparus aurata L. waste waters
Miguel Jiménez del Río, Z. Ramazanov, G. García-Reina
Ulva rigida C. Ag. was cultivated in 750 1 tanks at different densities and flow rates with waste waters from Sparus aurata cultivation systems, to estimate the conditions for optimizing biofiltering efficiency and yield. To maximize both characteristics: i) seaweed density should be adjusted to 2.7 g FW l -1 (1.2 kg m-2) and ii) NH4+-nitrogen flow should be (at least) 150 mmo1 m-2 d-l. Such conditions will yield 27 g DW m-2 d-l with uptake efficiencies of 76 % of the daily input in our system at 12 volumes d-l (110 mmo1 m-2 d-l) at seaweed : fish biomass ratio of 1:4. NH4+ removal efficiencies would probably be increased if fish were feed as early as possible in the morning to provide maximum NH4+ concentrations during the light period, as uptake efficiencies are higher than in the dark.