Coagulation and Microfiltration Application for Sugarcane Vinasse Clarification

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Coagulation and Microfiltration Application for Sugarcane Vinasse Clarification Gabriel Dibbern Sacchi & Luan de Souza Leite & Marco Antonio Penalva Reali & Andressa Bichara & Mirna Helena Regali Seleghim

Received: 14 August 2020 / Accepted: 25 November 2020 # The Author(s), under exclusive licence to Springer Nature Switzerland AG part of Springer Nature 2020

Abstract 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 °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. G. D. Sacchi (*) : L. d. S. Leite : M. A. P. Reali : A. Bichara Department of Hydraulics and Sanitation, São Carlos School of Engineering, University of São Paulo, Av. Trabalhador São-Carlense, 400, São Carlos, São Paulo 13566-590, Brazil e-mail: [email protected] M. H. R. Seleghim Department of Ecology and Evolutionary Biology, Center of Biological and Health Sciences, Federal University of São Carlos (UFSCar), Rod. Washington Luiz, São Carlos, São Paulo 13565-905, Brazil

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.

Keywords Cross-flow . Distillery effluent . Pretreatment . Continuous mode

1 Introduction Sugarcane vinasse is the main waste effluent from the ethanol industry, which shows a dark color, high chemical oxygen demand (COD, 22,000 to 100,000 mg O2 L−1), low pH (4.0 to 5.0), and an unpleasant smell (de Godoi et al. 2019; España-Gamboa et al. 2011). Brazil’s ethanol production was projected at 33 billion liters in 2019 (Barros 2019). Considering that 12 L of vinasse is generated per each ethanol liter produced (van Haandel 2005), a huge vinasse volume of 396 billion liters was generated. Based on the current scenario, environmental concerns about its treatment and final disposal emerge. Microalgae have been appointed as a promising su