Determinación de las cargas de contaminación en aliviaderos de la red de alcantarillado combinado de la ciudad de Cuenca - Ecuador

Abstract

The combined sewer overflow (CSO) is one of the main causes of contamination in the receiving bodies during the rainy period. Ecuador does not have yet legislation related to the CSO processes. The objective of this research is to evaluate the behavior of three combined sewage discharges of the Tomebamba river in the city of Cuenca - Ecuador. For this, the registration of 18 CSO events has been carried out in the CSO El Vado, Multifamiliares and Coliseo. The following water quality parameters have been analyzed: conductivity, turbidity, BOD5, COD, fecal and total coliforms, nitrates, nitrites, ammoniacal nitrogen, ortho phosphate dissolved and total phosphorus. The results show that CSOs contribute to the deterioration of the water quality of the Tomebamba River during the rainy season. There is great variation in the typology of water. The Coliseo discharge does not comply with the national regulations regarding the parameters for effluent discharge in receiving water bodies. The relationship between rain and characteristics of the CSO was also analyzed through the canonical correlation analysis CCA and partial least squares regression PLSR. The result is a prediction model of pollutants based on precipitation parameters. The analysis determined that: (i) the maximum discharge rate of a CSO depends mainly on the maximum rainfall intensity (ii) the maximum rainfall intensity and average rainfall intensity, have an influence on the recorded average turbidity values (iii) The mean value of COD is related to the duration of the dry season prior to the precipitation event