Performance evaluation of an anaerobic/aerobic landfill-based digester using yard waste for energy and compost production

The objective of this study was to evaluate a new alternative for yard waste management by constructing, operating and monitoring a landfill-based two-stage batch digester (anaerobic/aerobic) with the recovery of energy and compost. The system was initially operated under anaerobic conditions for 366 days, after which the yard waste was aerated for an additional 191 days. Off gas generated from the aerobic stage was treated by biofilters. Net energy recovery was 84.3 MWh, or 46 kWh per million metric tons of wet waste (as received), and the biochemical methane potential of the treated waste decreased by 83% during the two-stage operation. The average removal efficiencies of volatile organic compounds and non-methane organic compounds in the biofilters were 96–99% and 68–99%, respectively.

► Biochemical methane potential decreased by 83% during the two-stage operation.
► Net energy produced was 84.3 MWh or 46 kWh per million metric tons (Mg).
► The average removal efficiency of volatile organic compounds (VOCs) was 96–99%.
► The average removal efficiency of non-methane organic compounds (NMOCs) was 68–99%.
► The two-stage batch digester proved to be simple to operate and cost-effective.