STOCHASTIC-ANALYSIS OF PROCESS-CONTROL MODELS

A stochastic dynamic mathematical model for a wastewater treatment plant is developed. The output of the plant was simulated for a period of several days under different random input conditions and different probability distributions of parameters. Differences between the deterministic and stochastic responses of the model are described, as is the effect of frequency of fluctuations of the stochastic inputs on responses of the model and on their variances. Although stochastic analysis cannot reduce the uncertainty in design, it can provide a more quantitative assessment of the uncertainty than can deterministic design and so can lead to better designs of process plants.