Mild chemical pretreatment of cassava pulp for enhancing high-load anaerobic digestion

Abstract

Lignocellulosic components limit the potential of starch-rich cassava pulp for high-load anaerobic digestion. Mild chemical pretreatments using 0.1%–3.0% (w/v) of H2SO4, HCl, NaOH, and KOH were investigated at low temperature (30 °C) for enhancing organic solubilization and methane production. Alkalis solubilized up to 54% of the chemical oxygen demand, degraded 53% of hemicellulose, and thus increased 18–33% of methane yield. The maximum methane yield was 324 ± 5 mL/gVS achieved by 2.0% NaOH pretreatment. Modified fed-batch BMP constructively elucidated the enhancing and hindering effects of pretreatment on methane production at high organic loading. Suitable mild pretreatment is essential for developing a practical digestion process at higher organic loading rates.