Comparative evaluation of the biochemical methane potential of waste activated sludge acetic acid and cellulose substrates under mesophilic and thermophilic anaerobic digestion

Knowing the biochemical methane potential of a substrate to biogas production is a preliminary to possible selection of the pre-anaerobic digestion technology and identifying the optimum reaction time. Following standard method to reactor assembly, feed preparation and monitoring of the specific methane yield, the two temperature systems are compared among substrates. As a result, the rate of biochemical methane yield from the waste activated sludge anaerobic digestion in the thermophilic case is much faster than the mesophilic. The specific methane yield and volatile solid removal of the waste activated sludge batch anaerobic digestion is 74% of the theoretical and 81% for the thermophilic while it is 57% theoretical and 76% for the mesophilic, respectively. However, the best methane yield is recorded for the acetic acid followed by the cellulose and sludge substrates, signifying the importance of sludge pretreatment to enhance degradability in anaerobic digestion. Also, the optimum reaction time for thermophilic and mesophilic systems is different.