Impact of Substrate Composition in Biomethane Production under Thermophilic Conditions

Abstract

Abstract-In this investigation, the anaerobic digestion (AD) results from different substrates were evaluated. By means of two co-digestion processes with cow dung, a good performance was observed in the first process and a poor production trend was seen in the second one. NaOH was used as chemical absorbent in two different bottles in the CO2 fixing unit to compare the volume of biomethane produced after purification. A batch anaerobic co-digestion was carried out in 500 mL digesters placed into a water bath at 45°C and maintained at the initial pH of 7. Important AD factors such as pH, Carbon and Nitrogen ratio (C/N), concentration, substrate composition were considered. Through an ultimate analysis, amount of Carbon (C), Hydrogen (H), Nitrogen (N), and Sulphur (S) were also discussed. The toxicity of other elements found in substrates appeared higher in the second process than in the first. It was concluded that the inhibitory elements identification and control before the biogas production process were primordial.