Extension of the anaerobic digestion model No. 1 (ADM1) to include phenol compounds biodegradation processes for simulating the anaerobic co-digestion of olive mill wastes at mesophilic temperature.

The anaerobic digestion model No. 1 (ADM1) was extended and enhanced to describe the anaerobic degradation processes of phenol compounds and homologues in olive mill wastewater (OMW) and olive mill solid waste (OMSW) at mesophilic temperature (37 degrees C). The original ADM1 basic structure was extended by to the inclusion of phenolic compounds degradation processes into benzoate and then into acetate. The inhibitory effect of phenolic compounds on the fermenting process was accounted for by the use of non-competitive inhibition functions. New sensitive phenolic and benzoate parameters were calibrated and validated using updated experimental data from our previous study dealing with the mesophilic anaerobic co-digestion of OMW with OMSW in semi-continuous tubular digesters. The simulating results revealed that the extended ADM1 could predict with adequate accuracy the steady-state results of gas flow rate, effluent pH and soluble phenol concentrations of various influent concentrations at different hydraulic retention times (HRTs).