In this paper, the IWA anaerobic digestion model No. 1 (ADM1) is applied to two case studies
from contract work on industrial treatment plants. The first was the assessment of acid addition for pH
decrease and avoidance of calcium carbonate (CaCO3) precipitation in a paper mill fed UASB. The
simulation work found, with a high degree of confidence, that acid dosing was neither economical for pH
control, nor had any real effect on the CaCO3 levels present in the reactor. A specific calcium carbonate
precipitation equation was added to the ADM1 to undertake this study. The second case study was an
assessment of the benefits of thermophilic (as opposed to mesophilic operation) for reduced ammonia
inhibition, improved stability and gas production in a solids digester at a gelatine production facility. Here, it
was predicted that thermophilic operation could not attain either goal to a satisfactory extent. In addition to
demonstrating the application of the ADM1 to the two systems, we have also assessed the predictions
generated in the case studies in terms of quality and utility