Multivariate and multiobjective optimization of tannery industry effluent treatment using Musa sp flower extract in the coagulation and flocculation process

Abstract

Several studies have focused in the tannery industry due to the high polluting potential of the effluent generated in leather processing; high concentrations of total chromium and organic load. However, the high costs attributed to the treatment of tanning residues explains why this material is not treated within the tannery industry. The extract from the flower of Musa sp, condensed and hydrolisable tanins, yet to be explored in literature was applied to remove organic matter from chemically enhanced primary treatment (CEPT) of total solids, turbidity and total chromium from a tanning industry and leather processing. The use of the flower extract of Musa sp. proposed in this study does not require flocculant polymers after the coagulation step. A central composite design response surface (CCD) was modelled by the factors: coagulant volume, pH and rotation. The optimization was performed according to the NBI algorithm in a mixed arrangement to determine optimal weights. The modeling from CCD and minimization of Global Standard Error determines the optimized conditions, turbidity removal, total cromium, hexavalent chromium and trivalente chromium of 78% and 65.4%, 39.43% and 61.02%, respectively, increasing the biodegradability from the ratio biochemical oxygen demand (COD) and chemical oxygen demand (COD) of 0.12–0.63.