Avaliação do extrato de Urera baccifera como coagulante no tratamento de efluente líquido de indústria de pescado

Abstract

Fish processing involves high water consumption, resulting in the production of large amounts of liquid effluents. Inorganic coagulants are widely used in the treatment of these effluents. However, they have disadvantages such as high cost and presence of metallic residues in the treated water. One option to the use of inorganic coagulants are the natural coagulants. Therefore, the evaluation of the extract from roots of Urera baccifera as a natural coagulant for fish processing industry effluent was made. In order to find the better operating conditions, the experimental planning central composite rotational design for two variables (pH and coagulant dosage) was used, with the turbidity removal percentage as response variable. The optimal region of operation, that achieved the greater removals, was detected in the pH 5 to 8 and in the coagulant dosage of 200 to 500 mL L-1. In toxicity evaluation with Artemia salina as bioindicator, the treatments with greater coagulant dosage (500 and 250 mL L-1) shows toxicity, this toxicity must be from the coagulant itself, thus the treatment with lower coagulant dosage (17 mL L-1) did not show toxicity. These results confirm the effectiveness of the extract from roots of Urera baccifera as a coagulant for turbidity removal from industrial effluents. However, this potential must be used carefully, because it raised others physicochemical parameters (chemical oxygen demand and total solids) of the effluent and showed toxicity in elevated dosages.