Biochemical methane potential assays to test the biogas production from the anaerobic digestion of sewage sludge and other organic matrices

The present paper shows the results of some anaerobic digestion batch assays carried out with the objective to test the biochemical methane potential of a sewage sludge taken from a wastewater treatment plant in Varese (Northern Italy). In order to optimize the waste treatment and consequently to increase the energetic yield of the process, some biological and chemical pre-treatments were applied to enhance the hydrolytic step. These pre-treatments mainly consisted of adding external enzymes or a nutrient solution able to create the optimal conditions for the reaction start-up. In addition, different organic matrices were added to sewage sludge with the aim of testing the benefits achievable by using co-digestion. The method used to check the biochemical methane potential was based on a volumetric test, which converted the displacement of a liquid barrier into the measure of biogas production. In order to do so, each assay was developed by using three different positions running in parallel.