Paper Title
Pretreatment Technologies for Enhancing Anaerobic Digestibility of Municipal Solid Wastes

Abstract
We conducted thermal and ultrasound pre-hydrolysis (THP and USP) of various biowastes (thickened waste activated sludge, primary sludge, source separated organics, and hog manure) under 22 different conditions. Regardless of significant differences in pre-hydrolysis conditions and type of biowastes, increase in biochemical methane potential from pre-hydrolyzed biowastes showed a reasonably linear correlation (R2=0.69) with moderate VSS removal efficiencies (20-40%). Although the increase in methane potential did not correlate significantly with aggressive VSS removal efficiencies (50-70%), an opposite trend was observed in comparison with moderate VSS removal efficiencies (20-40%). Interestingly, the degree of disintegration (COD solubilization) did not show any linear relationship with VSS removal efficiencies as well as an increase in methane potentials. Thus, VSS reduction during pre-hydrolysis should be considered as a unified performance indicator for various pre-hydrolysis methods. Moreover, our results indicate that moderate VSS destruction (20-40%) by pre-hydrolysis would be more efficient in enhancing methane productivity from different biowastes. Keywords - Anaerobic Digestion, Biogas Production, Solids Reduction, Pretreatment