Impacto de la precipitación pluvial en la turbidez del agua superficial usada para la potabilización en el cantón Azogues durante los años 2014 – 2020

Abstract

Significant natural precipitation events cause an increase in the turbidity of raw water used for drinking water treatment, triggering problems such as increased use of chemicals and difficulty in plant treatment capacity that ultimately affect the quality of treated water. The objective of this thesis was to analyze the impact of rainfall on the turbidity of the raw water entering the Mahuarcay Drinking Water Treatment Plant (PTAP-M) in the city of Azogues. The study included several stages; in the first stage, we worked with the historical data of precipitation, turbidity and amount of coagulant used for the period January 2014 - May 2020, data provided by the plant's management company, EMAPAL-EP; subsequently, we evaluated the representativeness of the data and its probability distribution. In the second stage, an analysis was made of the relationship between the turbidity of the raw water entering the PTAP-M and the rainfall measured directly from the meteorological stations near the raw water catchments. The relationship between these two variables was determined based on linear regression, artificial neural networks (ANN) and response surface methodology; 80% of the total available data was used for model calibration and the remaining 20% for validation. The mathematical models obtained predict unsatisfactorily the turbidity value of the raw water knowing the precipitation data. In the third and final stage, the chemical treatment effort in the PTAP-M was evaluated, for which a mathematical model was developed to describe the relationship between the chemical treatment effort (amount of coagulant), raw water quality (turbidity level) and rainfall; the modeling was carried out using multiple regression analysis methodologies, artificial neural networks (ANN) and response surface methodology. Finally, the results of this work showed that it was not possible to obtain models that are capable of optimally representing the real behavior, i.e., it was evident that the calculated models do not present the best results. Therefore, they do not allow to effectively predicting the turbidity value of the raw water entering the PTAP-M after a precipitation event; likewise, it is not possible to estimate with greater certainty the amount of coagulant to be used in the process