Anaerobic digestion of kitchen waste operating at two-phase mesophilic scale digester: the impact of system performance based on methane production

Abstract

In this study, a comparison between single and two-stage digester operating systems at mesophilic conditions was studied. The level of methane yield and percentage composition was a key factor in evaluating the digester system performance in which a setup of 4.5 m3 digester capacity was fed with kitchen waste generated daily within the campus of Nelson Mandela African Institution of Science and Technology (NM-AIST). Results revealed that a two-stage digester operation system produced a significantly higher methane level compared to a single-stage operation system (methane content of 69.6%; methane yield of 640.31 LCH4/KgVS vs 48%; 356 LCH4/KgVS). This study indicated that a two-stage operation digester system could maintain the pH at an optimum level even under higher loading conditions.