Enhancement of Anaerobic Digestion of Excess Municipal Sludge with Thermal and/or Oxidative Treatment

Abstract

The use of thermal and/or oxidative treatment to enhance anaerobic digestion of excess municipal sludge was evaluated. Different reactor configurations were studied. A “moderate” temperature (90°C) was used in the thermal treatment and hydrogen peroxide was the oxidant. Thermal treatment alone did not increase solids destruction. A maximum of 15.2% increase in volatile suspended solids (VSS) destruction was observed with the oxidative treatment. A synergistic effect was observed when both treatments were combined. The increase in VSS destruction when both cotreatments were applied (oxidative and thermal) ranged between 27.2 and 29.0%, depending on the reactors configuration. Parameters such as methane production, chemical oxygen demand removal, nitrogen and volatile fatty acids concentrations, and fecal coliforms removal were also evaluated for the different configurations studied.