Polynomilalization of bhargava models for DO sag elements

Abstract

The existing DO sag models of Streeter-Phelps have become obsolete in the present day context o, polluted streams in which a part of the BOD removal necessarily takes place through sedimentation which aspect is not accounted for in the Streetei-Phelps models. Bhargava's theoretically deriveo models for the DO sag parameters takes account of the almost linear removal of the settleable BOL along with the exponential decay of the non-settleable BOD. However, for the DO sag elements, the Bhargava models have two expressions, one each for times less than or greater than the transition time in which all the settleable BOD is removed. Polynomial zed forms of thé Bhargava models for the DO sag elements are developed which are shorter, simpler, single expression equivalent substitute and universally applicable without any regard to the transition time. Unlike the Streeter-Phelps or Bharga va models, the presented polynomial forms of Bharga va models have an additional advantage of evaluating the critical and inflexion dissolved oxygen deficit concentration directly and without first determining the times of occurrence of such concentrations. The material presented would add to the existing litera ture on the subject.