Enhancing Anaerobic Digestion of Pulp and Paper Mill Biosludge using Thermal Treatment in a Bench-scale System

Enhancing Anaerobic Digestion of Pulp and Paper Mill Biosludge Using Thermal Treatment in a Bench-Scale System Masters of Applied Science 2015 Xian Meng Huang Department of Chemical Engineering and Applied Chemistry, University of Toronto This study examines the feasibility of using a bench-scale anaerobic digestion (AD) system to treat pulp and paper mill biosludge. Three thermal treatment methods were studied: pre-treatment, intermediate treatment and post treatment. Thermal pre-treatment of biosludge resulted in overloading of the bench-scale reactor, causing the pH to drop significantly; this in turn caused reactor acidification. Intermediate thermal treatment of digestate had a positive impact on the digestibility of the biosludge; the specific methane yield increased by 76% and 29% in two separate bench-scale experiments. Post-treatment of digestate followed by further digestion was studied in BMP tests, and it was determined that the final specific methane yield increased by 43%. Overall, anaerobic digestion of pulp and paper mill biosludge has been proven to be successful at the bench-scale level, and thermal post-treatment methods have been shown to be effective at enhancing the digestibility of the biosludge.M.A.S