Treatment of red wine vinasses with non-conventional substrates for removing coloured compounds

Abstract

Vinasses from the wine industry were treated with different materials to remove colour as a first step for treatment. Peat, several composts and red mud from bauxite refining were evaluated as adsorbents for coloured compounds, and their performances compared to that of activated charcoal. Among the materials assayed, grape marc vermicompost gave the best results, followed by peat. A sharp decrease of absorbance between 400-800 nm took place in vinasses after the treatments with these two materials, whereas the other substrates did not reduce the colour of the vinasses as did activate charcoal, grape marc vermicompost and peat. Moreover, grape marc vermicompost and peat were activated on high temperatures or grinding, producing better results in colour removal, although with negative effects on the electrical conductivity and nutrient concentration in the wastewater. The results of the treatment of vinasses with activated charcoal were reproduced and even overcame, in the case of the reduction of the optical density of vinasses at 665 nm, using grape marc vermicompost.