Geração de biofloco em sistema de lodo ativado tratando efluente de carcinicultura

Abstract

Biological processes have been widely used to treat effluents due to the high rate of organic matter degradation and relatively low cost. The activated sludge system is one of the most suitable for treating shrimp effluents. In parallel, this system can generate suitable biofloc to supplement the nutritional needs of shrimp. The objective of this work was to produce biofloc in an activated sludge system reactor in laboratory scale, while treating effluents of the shrimp farming, to analyze its bromatological composition and to investigate the presence of Bacillus spp. The wastewater from the experimental shrimp culture was enriched with sugarcane molasses, nitrogen and phosphorus in the proportion 100C: 5N: 1P. The physical and chemical parameters such as pH, dissolved oxygen, volatile suspended solids, sedimentable solids, and Removal of COD were analyzed. Bacillus spp. were quantified by Standard Plate Count. These were found in all stages of the reactor (affluent to the system, aeration tank, decanter and effluent to the system), even in small amounts. COD removal efficiency was, on average, 68 ± 0.19%; Mean pH 7.6, dissolved oxygen ranged from 0.6 to 4.5 mg / L, mean volatile suspended solids of 2.88 ± 1.40 g / L. The biofloc presented 45.82% crude protein, 20.57% moisture and volatile, 1.54% ethereal extract, 0.22%, crude fiber and 8.71% mineral matter. The amount of crude protein was compatible with the nutritional requirement of the marine shrimp,sugesting it as an alternative to obtain biofloc that requires more studies. In addition, the removal of organic matter was sufficient to comply with Brazilian environmental legislation. As for Bacillus spp. they can be incorporated into the biofloc generated in aerobic treatment systems, constituting a possible alternative source for probiotics added to L. vannamei cultures.