DO Sag Model for Extremely Fast River Purification

Abstract

The classical Streeter‐Phelps models for computation of the biochemical oxygen demand (BOD) and dissolved oxygen (DO) deficit concentrations in the streams do not account for bioflocculation and setting of the settleable organic matter. These are therefore of little value in the accurate computation of the DO sag elements in polluted streams. The extremely fast BOD assimilation in rivers, based on the physiochemical linear removal of the settleable BOD with exponential laws for the nonsettleable BOD, was modeled by others and has been utilized here for evolving the models for the accurate prediction of the DO sag‐related elements. Case examples with river data are presented to show the utility of the evolved models for the prediction of DO sags (simple as well as compound DO sags).