In biogas plants, huge volumes of digestate are produced daily and stored in uncovered tanks, which leak
methane into the atmosphere and cause negative environmental impacts. To better understand the effect
that different operating parameters of anaerobic digestion plants have on digestate residual methane
yield, four digestate samples collected from plants with very different operations were analysed in batch
reactors. Their methane yields were very heterogeneous and varied between 2.88 and 37.63 NL/kgVS. The
methane yield was shown to be highly influenced by the A.D. plant Organic Loading Rate and by feedstock
quality; hydraulic retention time had only limited effects