Coagulation and Microfiltration Application for Sugarcane Vinasse Clarification

Sugarcane vinasse, also known as distillery wastewater, is a key by-product of the ethanol industry. Vinasse characteristics and their huge volume pose environmental concerns about the choice of treatment method. Microfiltration (MF) has been efficiently applied to vinasse clarification; however, it has been underexplored in the literature. In this context, the present study investigated the application of coagulation and cross-flow MF for vinasse clarification. To maximize the process efficiency, operational parameters were optimized using the one-factor-at-a-time method in batch tests. The optimal values were Superfloc C492 concentration of 5 mg L-1, backpulsing frequency of 10 min, and vinasse temperature of 45 degrees C, which showed a removal of 35.0, 86.0, and 99.9% for chemical oxygen demand (COD), color, and turbidity, respectively. The optimization process significantly improved the vinasse flux but did not show any influence in the permeate quality. Optimal parameters were successfully applied to the continuous mode in the MF system, which operated during 164 h at an average flux of 21.6 L h(-1) m(-2). High removals were reached for color (79.3%) and turbidity (99.6%), and low removal was found for COD (31.6%), which are in agreement with the batch mode tests. This work showed the importance of operational optimization, and the results provide valuable support for establishing practical guidelines for vinasse clarification in the ethanol industry. (AU)