Bioremediation of aquaculture wastewater using macroalgae and Artemia

Abstract

Aquaculture produces a significant amount of wastes, consisting of metabolic by-products, leading to general deterioration of water quality. An alternative for reducing nutrient excess is the use of biofilters that can effectively remove nutrients from the water. A laboratory study was conducted to test the efficacy of the macroalgae Gracilaria caudata and the microcrustacean Artemia franciscana to remove nutrients from aquaculture effluents. The experiment consisted of three treatments: macroalgae (1) macroalgae and Artemia (2), and only Artemia (3). The results indicated that the treatment 2 was the most efficient in removing the nitrogenated forms. The maximum reduction values were: NH4=29.8%; NO2=100%; NO3=72.4% and DIN=44.5%. In contrast, the nutrients concentration was significantly higher at the end of the experiment in the treatment 3 than in the other treatments (ANOVA: p<0,001). PO4 showed a significant increase during the experiment, especially in treatments 2 and 3 (ANOVA: p<0.001). The results showed that G. caudata and A. franciscana performed well in absorbing nitrogenated forms. This indicates that the use of these organisms as biofilters has the potential for being an ecologically correct practice and may contribute to improving the water quality of coastal regions.