Reduced BOD Loadings and Incresed Secondary Treatment Capacity Through In-Mill Process Improvements and a New Aerated Stabilizaion Basin, 1996 Environmental Conference Proceedings

After beginning construction of a new secondary fiber plant (OCC), record mill production rates increased the projected BOD load beyond what the existing wastewater treatment facilities could handle. Initially, Weyerhaeuser planned to use excess capacity at the municipal waste water treatment plant to treat effluent from the OCC plant, but could not work out an agreement that satisfied everyone’s needs. Two in-mill process changes were implemented to reduce BOD loadings to bridge the gap between startup of the OCC plant in August 1993, and completion of an Aerated Stabilization Basin (ASB) in April 1995. These projects were an upgrade to the foul condensate steam distillation system (CSD) and a vacuum pump seal water recycle system which was installed on the larger of two paper machines. The in-mill projects and the new ASB have allowed the new OCC plant to reach targeted production rates and the mill to set repeated production records while comfortably maintaining compliance with one of the most stringent discharge permits in the nation.