Cost-Effective Design and Operation of Activated Sludge Aeration Systems using Process Modeling

A process simulator, with an integrated aeration model, can be used to optimize diffuser density, test alternate control strategies, and reduce energy use. Dynamic simulation using a calibrated simulator was used at the Union Sanitary District Alvarado Wastewater Treatment Plant to estimate ideal aeration air demands — with ideally optimized aeration system control — throughout a typical year. The results were used to recommend diffuser density changes along the plug-flow tank and to rationally select the number of control zones based upon capital, operations, and maintenance costs of additional dissolved oxygen probes and air flow control valves. The simulated frequency of air demands can be used for efficient blower sizing.