Modelling non-ideal bio-physical-chemical effects on high-solids anaerobic digestion of the organic fraction of municipal solid waste. (15th May 2019) - Pastor-Poquet, Vicente
Abstract: This study evaluates the main effects of including 'non-ideal' bio-physical-chemical corrections in high-solids anaerobic digestion (HS-AD) of the organic fraction of municipal solid waste (OFMSW), at total solid (TS) between 10 and 40%. As a novel approach, a simple 'non-ideal' module, accounting for the effects of ionic strength ( I ) on the main acid-base equilibriums, was coupled to a HS-AD model, to jointly evaluate the effects of 'non-ideality' and the TS content dynamics on the HS-AD bio-physical-chemistry. 'Non-ideality' influenced the pH, concentration of inhibitors (i.e. NH3 ), and liquid-gas transfer (i.e. CO2 ), particularly at higher TS (i.e. ≥ 20%). Meanwhile, fitting the experimental data for batch assays at 15% TS showed that HS-AD of OFMSW might be operated at I ≥ 0.5 M. Therefore, all HS-AD simulations should account for 'non-ideal' corrections, when assessing the main inhibitory mechanisms (i.e. NH3 buildup and acidification) potentially occurring in HS-AD of OFMSW. Graphical abstract: Image 1 Highlights: Ionic strength can be higher than 0.5 M in high-solids anaerobic digestion. Non-ideality strongly affects NH3 inhibition and CO2 liquid-gas transfer. Non-ideal effects on anaerobic digestion are exacerbated at total solids ≥20%. High-solids simulations jointly require non-ideality and reactor mass/volume dynamics. Non-ideality is interrelated to NH3 inhibition parameters and the model structure.