Integrated Analysis of Sludge Management and Biogas Production from COD Removal in Wastewater Treatment

Sludge management is a critical aspect of wastewater treatment, particularly in industries such as pulp and paper, where high organic loads and suspended solids challenge system efficiency, operational costs, and sustainability. This study evaluates sludge generation, concentration, withdrawal frequency, and associated gas production through COD removal analysis of pulp and paper wastewater. The sludge volume was estimated using COD removal data, yielding approximately 0.04675 m³ per day at a solids concentration of 20,000 ppm. Sludge concentration was determined from influent and effluent COD differences, with values indicating effective organic matter removal. Gas production analysis revealed that COD removal directly correlates with biogas yield, with a calculated biogas volume of 0.32725 m³, comprising approximately 60% methane (0.196 m³) and 40% carbon dioxide (0.131 m³) under typical conditions. Gas collection efficiency was highlighted as a key parameter for assessing system performance. Operational factors such as current density, power consumption, and hydraulic retention time (HRT) were also analyzed, demonstrating their influence on COD removal efficiency and energy balance. The results emphasize the interdependence of sludge management and gas production in optimizing pulp and paper wastewater treatment, offering insights for improving energy recovery and ensuring sustainable plant operation.