Ultrasound assisted alkaline pre-treatment of sugarcane filter mud for performance enhancement in biogas production

Sugar cane filter mud pre-treated by combined ultrasound-alkaline pre-treatment at different NaOH loading rates (0.25%-6%) and pre-treatment time (5 min to 60 min) performed in batch reactors under mesophilic conditions ((37±1)°C). Central composite design (CCD) was used to assess the effects on the chemical oxygen demand (COD) solubilisation, volatile fatty acid (VFA) concentration and methane yield. All pre-treatments were found significant to enhance methane yield (up to 39.49%) compared to the untreated filter mud. In general, results demonstrated the effectiveness of ultrasound assisted alkaline pre-treatment while increasing both NaOH loadings and pre-treatment time. Pre-treatment also increased the CODs solubilisation as well as VFA concentration, the optimal Initial CODs and VFA of 12 212 mg/L and 5830.97 mg/L, as determined by response surface methodology were noted on E9. Finally, modified Gompertz model was applied successfully to study kinetic of biogas production data, and showed an excellent fit.