Effects of thermal hydrolysis on sludge from Kraft pulp mill wastewater treatment

Abstract

Thermal hydrolysis (TH) is a widely used technology to enhance sludge anaerobic biodegradability. However, it has not been applied to biological sludge from industrial wastewater treatment. In the present work, TH was applied to the sludge from the aerobic treatment of wastewater generated by a Kraft pulp mill industry. Microscopic observations of the sludge with and without TH were made. Response surfaces are presented for the different variables tested (soluble Chemical Oxygen Demand (CODs), Volatile Suspended Solids to Suspended Solids ratio (VSS/VS), and soluble Total Kjeldhal Nitrogen (TKNs). Increases of 600% for CODs and TKNs concentrations were obtained. Reductions were observed for the VSS/VS ratio values from 23% up to 68%.