Enhancement of methane production from anaerobic digestion using different manganese species

The enhancement of methane (CH 4 ) production by metal addition during anaerobic digestion (AD) of organic waste has drawn much attention in recent years. In this study, four different forms of manganese (Mn, MnO, Mn 2 O 3, and MnO 2 ) were applied at the beginning of AD to investigate their effects on CH 4 production. Results suggested that both Mn and the three manganese oxides accelerated CH 4 generation. Mn and MnO showed thehigheset carbon conversion rates (about 67%) but the Mn group generated more CH 4 (330 mL g −1 VS) than MnO. Moreover, the duration of lag phases for CH 4 production was in the following order: MnO