An experiment on Fenton degradation of sugarcane vinasse was carried out to determine its effect on the wastewater characteristics. Vinasse, a by-product of distillation in the bioethanol industry, contains high organic matter, as the value of chemical oxygen demand (COD) is >100,000 mg/L and BOD 5 is 31,250 mg/L. The Fenton reaction is one of the advanced oxidation process (AOP) methods which has been widely applied for the treatment of wastewater containing organic pollutants and contaminants. This method utilizes hydroxyl radical ( • OH) produced from the catalyzing reaction between Fe 2+ or Fe 3+ and hydrogen peroxide. The effect of pH, the ratio of [H 2 O 2 ] and [COD], and the ratio of [H 2 O 2 ] to [Fe 3+ ] were studied in this research to evaluate the Fenton reaction. Results from this experiment showed that treatment of vinasse using the Fenton reaction decreased the COD value to 48.10%, and its biodegradability enhanced almost two times at a pH value of 3.8, a ratio of [H 2 O 2 ] to [COD] of 0.62, and a ratio of [H 2 O 2 ] to [Fe 3+ ] of 50 (g/g), which demonstrated that the Fenton treatment was effective to reduce organic matter of sugarcane vinasse. Three kinetic models (first order, second order, and Behnajad-Modirshahla-Ghanbery (BMG) kinetic model) were used to evaluate the degradation of the COD value. On the basis of the value of R 2 (coefficient of determination), we suggested that BMG represented the best kinetic model. This study finds that the Fenton treatment is able to mitigate the environmental impacts of sugarcane vinasse.

Sugarcane vinasse is one of the resources with a high potential for biogas production. However, its high value of COD (>100 g/L) and poor biodegradability could present substrate inhibition during anaerobic digestion. Thus, pretreatment techniques seem necessary for improving the process efficiency and enhancing biogas yield from sugarcane vinasse. In this study, the pretreatment process has been carried out using Fenton reagent, which utilizes the hydroxyl radical produced from the catalyzing reaction between hydrogen peroxide and Fe2+ or Fe3+. Sugarcane vinasse as substrate was pretreated using Fenton reaction at different doses of 30% H2O2 within the range of 15 to 80 g/L. Through Fenton pretreatment, the biodegradability of sugarcane vinasse and biogas production was markedly increased. The optimum dose of H2O2 for Fenton pretreatment of biogas production from sugarcane vinasse was 60 g/L. At this pretreatment condition, the cumulative biogas yield was 124.39 mL/g sCOD, and the methane content was 52.6%. The methane content of biogas from Fenton-pretreated vinasse increased approximately four times higher (from 11.3% to 52.6%) compared to the untreated sugarcane vinasse as control. These results indicate that Fenton pretreatment can be applied to improve substrate biodegradability and enhance biogas production from sugarcane vinasse.