Analog Simulation of Activated Sludge Systems

Analog computer solutions of activated sludge design equations are presented for constant, shock, and periodic feed input conditions. System responses of the aerated lagoon, extended aeration, and separate sludge wasting activated sludge systems to these different inputs are analyzed with the following conclusions: (1) The analog computer can be used to solve nonlinear differential equations for both steady-state and transient solutions; (2) operational changes caused by different plant influents, e.g., shock and periodic loads, and response comparisons of different activated sludge systems to such inputs can be determined using the analog computer; and (3) research is necessary to confirm the ability of present design expressions to describe transient changes in actual treatment plants.