Performance of a novel two-phase continuously fed leach bed reactor for demand-based biogas production from maize silage

• High performance novel two-phase continuously fed leach bed reactor (LBR).
• Prevention of digester failure by combination of LBR with anaerobic filter.
• Gentle mixing and high biomass concentration by means of a floating bed.
• Demand-driven methane production directly from the digester.
• Increase of methane production of 50–60% per day compared to constant feeding.

This study investigated the potential of producing biogas on demand from maize silage using a novel two-phase continuously fed leach bed reactor (LBR) which is connected to an anaerobic filter (AF). Six different feeding patterns, each for 1 week, were studied at a weekly average of a volatile solids (VS) loading rate of 4.5 g L−1 d−1 and a temperature of 38 °C. Methane production from the LBR and AF responded directly proportional to the VS load from the different daily feeding and resulted in an increase up to 50–60% per day, compared to constant feeding each day. The feeding patterns had no impact on VS methane yield which corresponded on average to 330 L kg−1. In spite of some daily shock loadings, carried out during the different feeding patterns study, the reactor performance was not affected. A robust and reliable biogas production from stalky biomass was demonstrated.