Treatment of effluents from marine shrimp culture with biofloc technology: Production of Arthrospira (Spirulina) platensis (cyanobacteria) and nutrient removal.

The aim of the current study was to evaluate the growth of Arthrospira platensis in the effluent of Pacific white shrimp Litopenaues vannamei grown in biofloc systems. In the first experiment, A. platensis grew for 12 days in different dilutions (100, 10, 1%) of effluent and in the fertilizer medium in order to determine ideal dilution for the growth of the microalgae in the effluent. At the end of the experiment, the biofloc 100% treatment showed a significantly higher cell density than the fertilizer medium treatment. A second experiment, which lasted for 20 days, was conducted in order to evaluate the growth and bioremediation potential in treatments without total suspended solids, which were removed by decantation, and untreated effluent. The final biomass in the biofloc treatment was 0.50 ± 0.59 g/L and 0.18 ± 0.14 g/L in the biofloc decanted treatment. Both treatments removed 90% of phosphate from the effluent. Nitrate values oscillated throughout the experiment. Thus, it is possible to affirm that the cultivation of A. platensis can be used as a tool to reduce the nitrogen and phosphate loads in the effluent of L. vannamei raised in biofloc systems. [ABSTRACT FROM AUTHOR]