Vinasse degradation using Pleurotus sajor-caju in a combined biological - Electrochemical oxidation treatment

Industrial wastewater treatment, by combined processes, has recently been seen as a novel and economically attractive strategy. The use of Pleurotus sajor-caju, followed by electrochemical oxidation (EO) for sugarcane vinasse degradation was investigated. Vinasse degradation treatment with P. sajor-caju yielded efficient color removal (97%), turbidity (99%), chemical oxygen demand (COD) (50.6%), and total organic carbon (TOC) (57.3%). Ligninolytic enzyme production was seen, and the highest lactase activity were obtained after 12th day of fermentation (varying between 341-400 UI L-1) and for peroxidase manganese the highest activity was seen between the 9th and 12th day of fermentation (varying between 1400-1494 UI L-1). Concomitantly, the mycelial biomass presented a high concentration (13.63 g L-1) on the 15th day of growth. In optimized conditions, the EO using as anode Ti/(RuO2)(0.7)(IrO2)(0.1)(Sb2O3)(0.2) further degraded vinasse, reaching a final color removal of 100%, COD of 66% and TOC of 61%. This additional procedure allowed the elimination of vinasse toxicity reaching 0% lethality for Lactuca sativa and Raphidocelis subcapitata.