Kinetic studies of alkaline-pretreated corn stover co-digested with upset dairy manure under solid-state

Abstract Prolonged lag phase and reactor instability make methane yield description and prediction challenging in upset solid-state anaerobic digestion (SSAD). Seven kinetic models (first-order (FOM), modified first-order (MFOM), Fitzhugh (FzM), logistic (LM), modified logistic (MLM), Cone (CM), and modified Gompertz (MGM) were employed for treatment evaluation. The treatments were dairy manure blended with calcium pretreated stover (8% Ca CSDM) or sodium pretreated corn stover (4% Na CSDM) or 2% aqueous ammonia pretreated corn stover (2% NH4 CSDM), or 4% aqueous ammonia pretreated corn stover (4% NH4 CSDM). The LM, CM, MLM with MGM, and MGM best described methane yield for 4% Na CSDM, 2% NH4 CSDM, 4% NH4 CSDM, and 8% Ca CSDM, respectively. Optimal hydraulic retention time predicted for the least inhibited treatment, 8% Ca CSDM, was 60 days. Therefore, non-hydrolysis rate limiting models (LM, MLM, FzM, MGM, and CM) could simulate methane yield, design of reactor’s volume, and develop degradation rate models in full-scale SSAD.