Abstract:The effects of α-amylase on excess sludge thermal hydrolysis under aerobic conditions were investigated. It was found that sludge hydrolysis efficiency could be enhanced by amylase. When treated at the dosage of 0.5g/L of amylase, SCOD/TCOD in sludge could reach 30.98% under the optimal temperature 50℃, which was 7.68% higher than the control experiment. As a result of the interaction of amylase and thermal hydrolysis, sludge solids dissolved first and subsequently macromolecular carbohydrate was hydrolyzed into small-molecular sugar, and the protein in solid-phase released and further was hydrolyzed. The concentrations of both sugar and protein in supernatant showed an increase in the initial stage and then decrease later. After the addition of amylase, the highest concentration of sugar in supernatant could reach 271.43mg/L at 4h, while the protein reach 1437.37mg/L at 6h under 50℃ respectively. Furthermore, VSS dissolution rate and SCOD/TCOD were proved to be consistent with first-order reaction dynamic within prior 4h at 50℃ and reached balance after 4h, at which the VSS dissolution rate reached 22.01%.