Influence of gamma-ray irradiation on the biomethane production of sunflower seed cake

Batch mesophilic anaerobic digestion tests were performed to investigate the biogas and biomethane potential of sunflower seed cake (SuSC) after irradiation pretreatment applying various doses of γ-radiation (0-150 kGy). Sample exposure to γ-rays was carried out using a60Co source at a dose rate of 1.0 kGy/h. The experimental maximum biogas and biomethane yields were 312.4-557.2 mL/g VS and 141.2-336.5 mL/g VS, respectively, the maximum levels being achieved for untreated SuSC substrate. Compared to the untreated substrate, the biogas production of irradiated samples decreased by 1.3-1.8 times and that of biomethane by 1.2-2.4 times with an increase in the irradiation dose. Some hypotheses were discussed to explain the negative effect of γ-radiation on the process performances. Cone and modified Gompertz models were applied to predict the dynamics of biogas and biomethane production. © 2021, Politechnica University of Bucharest. All rights reserved.