Effect of anaerobic co-digestion of grape marc and winery wastewater on energy production

Vineyard waste and wastewater generated from wineries present significant risks to the environment if untreated. In this study, we carried out anaerobic co-digestion of grape marc and winery wastewater for energy production in the form of methane and material recovery. The results showed that milling the grape marc prior to being suspended in winery wastewater and inoculated with activated sludge in a 15 weeks batch digestion resulted in the production of 5.04 MJ/kg VS of energy compared with 0.97 MJ/kg VS from the non-milled treatment. Milling of grape marc also showed reduced CO2 emission, 4.95 l/kg VS compared with 9.96 l/kg VS from non-milled samples. The results suggest that physical pre-treatment of grape marc results in bioenergy production which is comparable to many other organic waste streams such as cattle slurry, hen litter and food processing waste offering significant potential for utilisation by the winery industry.