Degradation of the macro-drainage water quality of an urban basin in Northeastern Brazil

The growth of cities allied to the lack of investment in urban infrastructure has caused the deterioration of the environment and natural resources. In this context, illegal connections of sewage in rainwater drainage systems has become increasingly frequent, thus compromising the water quality of the same. Campina Grande, located in the state of Paraíba, northeastern Brazil, has been affected by this problem and, therefore, this work aims to evaluate the pollution in its macro-drainage system, within the urban basin of the Prado creek. For that, were analyzed quality indicators of water samples collected at eight points distributed along the Prado creek. In addition, a study was carried out regarding the canal’s self-purification capacity in front of the entire wastewater discharge. Through the laboratory analyzes, it was proven that the drainage water of the Prado canal presents typical concentrations of sanitary sewage with high polluting potential. The points that presented critical quality were: two and four, these being the places with priorities for interventions in the short term. It was noted that, across of the dissolved oxygen profile along the canal, it was verified that the self-purification capacity of the canal was largely exceeded.