ABSTRACT
The added activated carbon in the PACT unit reduced the transient temperature response time and improved the Biochemical oxygen demand removal efficiency. The effluent Chemical oxygen demand increased either due to reduced biodegradation of the glucose substrate or the release of metabolic intermediates of the biosludge. The activated carbon, must be responsible for the superior dissolved organic carbon (DOC) removal and the shorter response time to temperature shock. Laboratory experiments were run to determine the effects of temperature and the other remedial actions. Temperature changes were found to be the most important factor affecting DOC and color removal. The overflow is mixed with non-contact cooling water in a 15-acre settling basin before it is discharged to the river. Water quality is closely monitored for compliance with the National Pollution Discharge Elimination System Permit parameters. The actions taken to prevent a recurrence were to reduce the probability of a "toxic hit" since temperature control was economically prohibitive.
