Abstract
Vinasse is the main by-product of ethanol production. In 2005, its application was regulated in the state of Sao Paulo, so if it is to be applied to the fields, its volume must meet the established concentration regulations. Straw contains one-third of sugarcane calorific value and can be used for cogeneration. For these purposes, the project objective was to assess the effects of straw on the concentration of vinasse solids through physical and chemical processes, so its concentrated form could be used as biomass for cogeneration. For that, different concentrations of straw, ferric sulphate, and ferric chloride were used. Turbidity reduction was the parameter analysed. Both reagents were effective in reducing the turbidity. The 200 ppm of ferric chloride and 0.25% straw content reduced the turbidity by 55.02% and 400 ppm of ferric sulphate and 0.25% of straw reduced it by 57.96%. The addition of straw showed no significant effect in terms of the turbidity reduction, however, both best treatments had 0.25% straw content addition in it. Straw can be used to concentrate vinasse, contributing to the efficiency of the process and increasing the energy potential of the concentrated solids.