Comparison of the PACT(TM) and activated sludge processes, for the treatment of a kraft pulp mill wastewater.

Abstract

This study has compared the conventional activated sludge process to the Powdered Activated Carbon Treatment (PACT$\rm\sp{TM})$ process for the treatment of a bleached kraft mill effluent. The PACT$\rm\sp{TM}$ process involves the addition of powdered activated carbon (PAC) to the aeration basin of an activated sludge system. Powdered activated carbon has a very high surface area and is able to adsorb large amounts of hydrophobic compounds, such as organochlorines. This process was selected because it was likely to increase the removals of toxins including adsorbable organics halides (AOX) and because it had not been evaluated for this type of wastewater. Bench scale continuous flow reactors, with internal sludge recycle, were used in this study. The design and process control parameters varied included hydraulic retention time, solids retention time and powdered activated carbon dose. PAC doses of 0.1-1.0 g/L were used. Four feeds were used in this study, which were collected at different times, from a bleached kraft pulp mill batch operation. Two conceptual models for effluent SCOD prediction were developed and tested. (Abstract shortened by UMI.)