Evaluating Energy Reduction Alternatives Using Process Modeling Tools – A Case Study of Stickney WRP

Stickney Water Reclamation Plant treats an average wastewater flow of 742 MGD and consumes about 20,000 HP of energy to provide about 677 TPD of aeration. The facility’s permit requires that the effluent is discharged with a minimum effluent dissolved oxygen (DO) level of 6 mg/l. About 30% of the total aeration energy demand at the facility is utilized in raising the DO level to 8 mg/l in the reaeration step, and the facility is currently evaluating alternatives for reducing this energy demand. In this study, we evaluated the impact of a conventional aeration and High Purity Oxygen (HPO) hybrid mix on the energy footprint using a calibrated GPS-X™ process model of the plant. The modeling study indicated that the use of high purity oxygen (HPO) for effluent re aeration could potentially reduce the power demand by about 6, 800 HP (34%), corresponding to a decrease in the greenhouse gas footprint by about 30,750 metric tons of CO2/year. The paper also provides an overview of reaeration options and the key design variables to consider when evaluating them. Our work indicates that conventional aeration supplemented with HPO can b e an effective means of reducing the energy footprint of wastewater treatment facilities. We also show that process models can be a powerful tool for optimizing aeration solutions at wastewater facilities.