| Biological treatment of pulp and paper wastes by activated sludge is widely practiced in industry to reduce the organic content and toxicity of the wastewater. Most industrial applications require the treatment of a combination of streams from various processes. The composition of the combined stream varies since shock loadings and spills may occur. The objective of this research was to determine the effects of these variations on the microbial community and, ultimately, on the kinetics of the reduction of biological oxygen demand (BOD) and chemical oxygen demand (COD). This will improve the understanding of control requirements for the process.;Effluents from two mills in Quebec were examined. Initially, effluents from a chemithermomechanical pulp (CTMP) mill were used in this research. The objective was to study the effect of six different waste streams mixed with total mill effluent (0--100%) on the reduction of COD and on the microbial population. The remainder of this research focused on treating effluents from a Kraft mill and investigated the effect of hydraulic residence time (HRT) and step inputs of 1%, 2.5% and 5% black liquor on the reduction of COD and BOD5 and on the microbial population. (Abstract shortened by UMI.). |
