To compare the efficiency of flocculation of nanocomposites with other widely used treatments, 0.1% nanocomposite with 60 mg poly-DADMAC/g sepiolite was added to winery effluents, and the relative absorbance of the effluent (the ratio of the optical density at a given time related to the optical density before the addition of coagulant/flocculant) was compared to that of the nanocomposite components (sepiolite and poly-DADMAC) separately at the same added amounts of active compound. The efficiency of flocculation by 0.1% aluminum sulfate (alum) was also determined for comparison, since this is a widely used flocculant. Measurements were performed at three wavelengths (420, 450, and 480 nm), and the average relative absorbance values were evaluated.