Search

This study demonstrated the degradation of unionized acetate in anaerobic digestion at 45°C through the identification of kinetics and inhibition parameters. The kinetic parameters, Ks and rmax, were determined using Monod-based model for three different conditions, namely uninhibited, inhibited, and systems with high substrate condition. The Ks values for uninhibited condition were in the range of 0.124 to 0.191 mg/L as unionized HAc. Ks value of inhibited condition were at 0.027 mg/L as unionized HAc. Ks values for systems with high substrate condition were found to be in the range of 0.237 to 0.279 mg/L as unionized HAc. As for rmax, a 35°C anaerobic digestion system showed the highest value at 0.166 mg/L/day - greater than the values of all 45°C systems under all experimental conditions. Additionally, the inhibition parameter KI was also determined using the Michaelis-Menten model. The parameter was determined for inhibitory conditions resulting from high free NH3 content. The inhibition type was uncompetitive with KI value of 0.072 mg/L as unionized HAc. The outcomes suggested that the methanogens responsible for the digestion process at 45°C were thermo-tolerant acetateutilizing methanogens of Methanosarcinaceae species, and the system will be totally inhibited with the presence of high free NH3 content. [ABSTRACT FROM AUTHOR]