Assessment of pretreatment effects on anaerobic digestion of switchgrass: Economics-energy-environment (3E) analysis

Large-scale cultivation of switchgrass (SG) not only promotes the utilization efficiency of marginal land but also provides suitable feedstock for bioenergy production. To maximize the energy conversion capability of SG in anaerobic digestion (AD), various pretreatment strategies involved NaOH, KOH, Ca(OH)(2), H2O2, HCl, H2SO4, and steam explosion were performed and compared in this study. Results showed that the experimental methane yield of SG after pretreatment was enhanced from 46.3 mL(STP) g(vs)(-1) to a maximum value of 197.2 mL(STP) g(vs)(-1), with an improvement of 325.6%. Methane production process of SG after different pretreatments was well simulated by the modified Gompertz model. Meanwhile, structural and composition changes of SG after pretreatment were confirmed by scanning electron microscopy, X-ray diffraction, and component analysis. From perspective of economics, energy, and environment (3E), the 3% KOH pretreatment was determined as the optimal pretreatment strategy. This study laid the foundation for further development of SG treatment strategy and provided a promising insight for enhancing bioenergy conversion.