Efficient degradation of solid yeast biomass from ethanol industry by Fenton and UV-Fenton processes applying multivariate analysis

Abstract

Organic agro-industrial residues have been successfully used as biosorbents and promoting new uses from agricultural wastes benefits the economy. However, the allocation of a solid waste biosorbent after the sorption of contaminants has limited their effective application on a large scale as an alternative treatment of water and wastewaters. One solution could be degradation to convert the biosorbent material and adsorbed organic contaminants into environmental friendly compounds suitable for discharge. This study used an experimental design to evaluate the Fenton degradation of yeast biomass (YB) from the alcohol industry as a potential biosorbent. The efficiency of degradation was monitored according to the degraded mass (DM) and total organic carbon (TOC) remaining in the solution. The ANOVA showed an error of 9.7% for the effects and the media of interaction for the employed model for DM. Conducting the experiments with the best-predicted conditions (60 min, 25 g of YB, pH 3, 8,000 mg L^-1 H₂O₂ and 40 mg L^-1 Fe²⁺) with 30 W UV irradiation resulted in a YB reduction of 72 ± 2% with a TOC of 30 ± 2%. This suggests that an advanced oxidative process is an alternative for degradation of a biosorbent after sorption.