Avaliação de desempenho da Anomalocardia brasiliana e Gracilaria sp. como biofiltros de efluente de camarão

Abstract

The efficiency of an integrated system, using processes of filtration for bivalves and absorption for macroseaweed, to improve the quality of the water of shrimp fisheries, was evaluated through the analysis of chemical, physical and biological variable. The effluent ones in question had been resultant of the mixture of heterotrophic culture of Litopenaeus vannamei, and Farfantepenaeus subtillis. . The native species Anomalocardia brasiliana (bivalve) and the macroseaweed Gracilaria sp. they had been selected had its potential it aquaculture to be found north-eastern of Brazil. This experiment was make in two phases of 48h with two treatments. In the first phase, the first treatment (control), only with aeration and as, added Anomalocardia brasiliana (5 ind//L) with aeration. Already for the second phase the control remained alone with aeration and in the other treatment the Anomalocardia brasiliana and substituted by the macroseaweed Gracilaria sp. was removed (1g/L). The experimental drawing for both phases contemplated six experimental units (tanks), belonging three to control and three to the treatment in the first phase with A. brasiliana and in the second phase with the macroseaweed Gracilaria sp. Water collect had been carried through in the initial schedule and after six in six hours. The concentrations of clorophyll-a, pheophytin, total phosphorus total phosphate, inorgânic phosphate total ammonium, nitrate, nitrite, alkalinity, temperature, dissolved oxygen, salinity turbidez and pH analyzed shown that the two organisms biological filters had significantly reduced the concentration of variables pollutants in the effluent. However it was observed that in the treatment it has controlled almost had a reduction to zero of nitrite concentration and a gradual increase of nitrate. And that, in the first phase in the treatment with shellfish, about 40% of A.brasiliana was removed deceased after the 48 hours of the experiment. Other studies must be facts, leading in account this reduction of the nitrite in the effluent one only with aeration in this space of time, and propitious a habitat more similar to the one of the nature to the A.brasiliana.