Modeling of Dissolved Oxygen (O2) Dynamics on the Left Bank of the Congo River; Port Ex Onatra River City

Abstract

The water quality of the Congo River is affected by industrial discharges. In this study, the evaluation of their impact was carried out using a mathematical approach. Used as water quality management tools, mathematical models are developed through an iterative process. The Streeter-Phelps model was used as a base model, and the methodological approach was that of Eckenfelder. This consisted of a campaign of parameter measurements that influence the dissolved oxygen content, a statistical treatment of data, a determination of the different global kinetic constants (K 1 and K 2 ) and the evaluation of the model by the Nash criterion. The results obtained are 2.26 j -1 and 13.26 j -1 respectively for the K 2 reaeration and deoxygenation K 1 constants; 498 mg / L for the initial oxygen biochemical demand (L 0 ) and 3.82 mg / L for the initial oxygen deficiency (OD); 1.4767 j -1 for the degradation constant of the organic matter k d and 1.000621805 for the ratio a (L 0 /L (5) ); generated a theoretical dissolved oxygen profile different from the experimental profile but which nevertheless allowed to simulate the fluctuations of the dissolved oxygen with the organic load. The statistical processing of the data has increased the reliability of the measurement campaign. The low value found for the Nash criterion (0,1756506) showed that this model should be adjusted to better evaluate the oxygen content.