Improving Biogas Yield Production at Room Temperature by Chemical Pretreatment

Abstract

The present study focuses on the experimental research of the effect of alkaline chemical pretreatment by KOH on biogas production from anaerobic digestion of lagoon station’s sludge (dry basis) under mesophilic conditions (35± 2 °C). Different concentrations of KOH, i.e. 1, 2.5, 5 and 7.5% (w/w), were tested for 24 hours at room temperature. The results obtained after two months of digestion, based on the total volume of biogas measured, clearly indicate that the chemical alkaline pretreatment has a positive effect on the anaerobic digestion, since the amount of biogas produced increased by 35.3 % when the concentration of KOH was 5%. Indeed, according to the selected operating conditions, this concentration is considered optimal. Therefore, above this concentration, a blockage and inhibition of the methanogenic activity of the anaerobic digestion process were observed. These results also indicate that the alkaline chemical pretreatment can improve the CH4 content of the biogas obtained.