Predicting the effects of integrating mineral wastes in anaerobic digestion of OFMSW using first-order and Gompertz models from biomethane potential assays

Previous studies found mineral wastes (MW; incineration bottom ash (IBA), cement based waste (CBW), Fly ash (FA) and boiler ash (BA) are a promising resource for the macro-/micronutrients necessary for anaerobic digestion (AD) processes. The current study used first-order and modified Gompertz models from BMP assays to investigate the effects of integrating MW on the AD of OFMSW at 37 °C. Results from the first-order model showed a 45% increase in the specific growth rate of microorganisms (μ) in the MW- supplemented BMP compared to the control. Gompertz model results indicated that the IBA, CBW, FA and BA BMP amended assays obtained the highest K values (45–54 mL CH4 g VS−1 d−1) than the control (K ∼ 31 mL CH4 g VS−1 d−1), with no significant adverse effects of co-digestion of OFMSW with MW on the length of the lag phase (λ) in BMP assays (λ = 1.89 ± 0.07 days for IBA, CBW and BA amended assays compared to 1.5 ± 0.01 days for the control). However, FA amended assays had a greater λ value (3.66 ± 0.1 days). The MW provided both alkalinity and released several trace elements at concentrations within the optimal ranges for methanogenic archaea.