Regular articleInvestigating the possibility of applying an ADM1 based model to a full-scale co-digestion plant

- Simulated biogas, methane outflow, and NH4-N showed a good fit, IoA 0.61-0.78.
- Extensive analysis needed for modeling is a hindrance in industrial application.
- Increasing VS to the digester increased methane from 1.5 to more than 2 million Nm3.
- Substrate utilization decreased from 264 Nm3/t-VS to less than 215 Nm3/t-VS.

This study investigated the possibility of using a model based on the anaerobic digestion model no. 1 (ADM1) on a full-scale 4000 m3 digester in order to understand how such theoretical models can be applied to a real industrial process. The industrial scale digester co-digests the organic fraction of municipal solid waste, grease trap sludge, and ley crop silage with varying feed rates and amounts of volatile solids. A year of process data was collected. Biogas flow, methane content/flow, and ammonia nitrogen were the variables that the model was best at predicting (index of agreement at 0.78, 0.61/0.77, and 0.68, respectively). The model was also used to investigate the effect of increasing the volatile solids (VS) concentration entering the digester. According to simulation results, increasing the influent VS concentration will increase biogas and methane outflow (from 1.5 million Nm3 methane to more than 2 million Nm3 methane), but decrease the amounts of biogas/methane per unit of volatile solids (from about 264 Nm3 methane per tonne VS to below 215 Nm3 methane per tonne VS).