Spatial Modeling of Dissolved Oxygen in Wastewater from the Quebrada “Ortega” of the Quito Canton, Pichincha Province

The objective of this work is to perform a spatial modeling of dissolved oxygen in wastewater discharged without prior treatment and directly to the “Ortega” stream located at the south of Quito. Wastewater disposal has become a serious problem caused by population growth in the surrounding area, affecting the quality of water, soil and air. For this study it was necessary to analyze oxygen depletion, known as the Streeter and Phelps model, which allows forecasting changes in the amount of oxygen as a function of Biochemical Oxygen Dissolved and the reaeration of the receiving body current. In addition, using ArcGIS software, the dynamics of the self-purification process of dissolved oxygen was modeled graphically to know the behavior and dispersion of this parameter and determine the water quality. This study concludes that despite the existing pollution, after a period of time, the water quality will improve due to physical and biological processes. The used model requires field data; however, it does not estimate the possible alterations that may occur with a large new volume discharge. By means of a bibliographic review a methodology was determined, which allows some fittings in its calculations for better performance. In addition, other possible parameters should be evaluated for the application of studies in bodies of water to determine their realistic state and determine if they accomplish the maximum permissible limits based on current legal regulations.