It is well know that each cubic meter (m3) of biogas contains the equivalent of 5-7.5 kWh of calorific
value, if the composition of CH4 lies between 50-75% of the total biogas composition [1]. Literature
references report that 0.29 to 0.33 Nm3 of CH4 can be produced for each kilogram of Chemical Oxygen
Demand (COD) digested at 35°C [2, 3]. Furthermore, hydrogen (H2) represents one of the most promising
steps toward a sustainable energy system, due to its high energy content per unit weight 120.21 MJ/kg
(while CH4 is only 50.2 MJ/kg), and its potential as a renewable energy source [4].