Biomethane potential of wine lees from mesophilic anaerobic digestion

Wine lees (WL) are undervalued residues from the wine-making process. Anaerobic digestion (AD) of WL is highly challenging due to the acidic pH and high content of readily biodegradable compounds. This study investigated the biomethane potential (BMP) of 3 WL samples through mesophilic batch tests fed with 2–3 % total solids. The influence of wood-based biochar (BC), considering 2 different BCs and doses (3 and 10 g L- 1), was also assessed. BMP values up to 1.257 Nm3 kgVS - 1 and 92–96 % soluble COD removal were recorded. However, the inhibition of methanogenesis was observed due to organic acids accumulation exceeding 21–24 g L- 1. BC addition didn’t improve biomethane production in the considered experimental conditions. This study proved that WL is a highly attractive AD substrate, considering its high biodegradability and availability throughout the year, although the process must be carefully operated.