Enhancing degradation and biogas production during anaerobic digestion of food waste using alkali pretreatment.

Alkali pretreatment of anaerobic digestion (AD) was investigated as a strategy to degrade complex organic matter such as fats. AD of food waste (FW) with alkali pretreatment was conducted using batch assays and long-term experiments for 70 days in two reactors. The aim of this study was to compare the impact of alkali pretreatment on solubilization and biogas production and to evaluate the performance in reactors with that of the untreated FW. The alkali pretreatment enhanced the solubilization of organic matter. The best biogas yield (829 mL/g VS) and methane content (65.48%) were obtained by the pretreatment with 1% CaO with the highest P (66.06%) of biodegradable soluble materials. The long-term reactors with pretreatment performed more steadily with higher biogas production under organic loading rates (OLR) over 5 g VS/(L⋅d). The bacterial community structure was different under various conditions. Methanosaeta and Methanospirillum were the dominant archaea in this study, while Methanosaeta increased in R1 at OLR of 6 g VS/(L⋅d). The study concluded that alkali pretreatment with 1% CaO appeared as a potential strategy for AD of FW.