Using Object Pascal and Matlab, a program was developed for Streeter Phelps modeling of self-purification. Boundary conditions suggested by Chapra were incorporated that permit the simulation of DO and BOD5 profiles considering multiple point sources along the flow path and a correction for conditions of anaerobiosis, which lead to negative DO and erroneous previsions in Streeter Phelps modeling. A method of automatic calibration, based on minimizing square deviations between simulated and observed concentrations, for obtaining the coefficients of deoxygenation and reaeration, was incorporated also. Various simulations for testing the program were performed: one for automatic calibration and two for boundary conditions. In all cases a good performance was obtained. The program may serve equally as a teaching instrument in environmental sciences classes and as a working tool in water quality management.
Streeter Phelps modeling; calibration; anaerobiosis
