Kinetics on anaerobic co-digestion of bagasse and digested cow manure with short hydraulic retention time

Abstract

The anaerobic co-digestion of bagasse with digested cow manure was operated in 3 l semi-continuous reactor under mesophlic temperature at 34 ± 1°C. Short hydraulic retention time and high organic loading rate applied were 10 days and 3.465 kg volatile solids (VS)/m3.day, respectively. Anaerobic co-digestion of bagasse with digested cow manure obtained higher biogas yield (69 ml/g VS) compared with the anaerobic digestion of digested cow manure alone (20.42 ml/g.VS). Kinetic assessment revealed that the maximum specific growth rate, the maximum rate of substrate consumption, halfvelocity constant, endogenous decay constant and microbial growth yield obtained were 3.917 day-1, 870.309 mg/mg, 15.09 mg/l, 8.1518 day-1 and 0.0193 mg/mg, respectively. This result indicated that a longer retention time was required to allow the bacterial growth.