Determination of the kinetic constants of anaerobic digestion of sugar-mill-mud waste (SMMW)

The kinetics of the anaerobic digestion of sugar-mill-mud waste (SMMW), the solid residue of the sugar-cane-juice clarification process, were investigated. Laboratory-scale experiments were carried out in a 1-l volume, completely mixed digester at SMMW loadings from 40 to 160 ml with a substrate concentration of 48.3 g COD/l. Assuming the overall anaerobic digestion process conformed to first-order kinetics, the specific rate constant Ko was determined for each of the loadings applied. The values obtained decreased from 1.76 to 0.05 1/day when the loading of SMMW applied was increased from 40 to 140 ml; this showed an inhibition phenomenon. The value of the methane yield coefficient (Yp) was 0.25 l CH4STP/g COD removed.