Integrated application of water quality modeling and quality retention curves as a tool for water resources management in the Piauitinga river basin, in Sergipe

Abstract

The present work aims to propose a methodology to support the future process of framing surface watercourses in the Piauitinga river basin, based on the concomitant application of water quality modeling and quality retention curves. Two conditions were established for water quality simulations, the current condition being 0% efficiency and the second considering an efficiency of 70% removal of biochemical oxygen demand (BOD), considering the scenarios of occurrence and non-occurrence of self-purification, for the year 2024. Total loads of BOD_5.20 were estimated in the basin's ottobasins, at level 6, considering domestic sewage and industrial effluents as polluting sources. Using the QUAL-UFMG model, the BOD_5.20 and Dissolved Oxygen (DO) profiles were simulated along the Piauitinga River. The quality retention curves for the BOD_5.20 parameter were constructed for freshwater rivers, classes 1, 2 and 3. The self-purification capacity of the Piauitinga river allowed a reduction of over 25% of the total BOD_5.20 load, indicating the need to expand the coverage of sewage treatment services in the study area. The results demonstrate that the adopted methodology proved to be adequate to assist the process of framing water bodies.