Effect of Biochemical Pretreatment and Nutrient Supplementation on Anaerobic Co-Digestion of Sugarcane Press Mud and Distillery Effluent

Abstract

Laboratory-scale anaerobic digesters were fabricated and used in the co-digestion of press mud and distillery effluent to investigate the effect of pretreatments (biological/enzymatic and chemical/alkaline) and nutrient supplementation for enhanced biogas production. The findings of this study showed that maximum biogas yield (502.86 mL/g TVSadded) with maximum percentage of methane (55%) was obtained in combined enzymatic and alkaline (calcium hydroxide) pretreatment with addition of nutrients (i.e., B6). Combined alkaline pretreatment and nutrient supplementation resulted to a 55.07% increase in biogas yield compared to the control. Sole nutrient addition enhanced the yield by 64.38%. However, single alkaline pretreatment presented inhibitory effect which resulted to a 22.48% decrease in biogas production. Moreover, the percentage of methane gas in the biogas samples was between 14 and 55%. Samples dosed with enzymes resulted to better methane yields (>50%) than the samples without enzymes. Highest reductions in BOD, COD and TSS were also achieved in sample B6. Thus, enzymes, especially when combined with other methods, have potential for improving biogas production from sugarcane wastes.