Dosificación del coagulante policloruro de aluminio (coagulante) - polímero aniónico (floculante) como sustituto del sulfato de aluminio en la planta de tratamiento de agua potable de Tixán

Abstract

This study was conducted at the "Tixán" Drinking Water Treatment Plant in Cuenca, with the objective of substituting aluminum sulfate with poly aluminum chloride (PAC) as a coagulant due to its enhanced efficiency in turbidity removal, reduced residual aluminum content, and a broader pH operational range. The primary goal is to determine the optimal PAC dosage as a coagulant to meet color, pH, and turbidity parameters in accordance with established standards. Initially, a fixed dosage of an anionic polyacrylamide-based (PA) flocculant was determined through jar tests, followed by experiments involving the PAC coagulant. Water samples were collected from the plant during the months of March, April, May and June 2023. Eleven trials were conducted to evaluate various amounts of PAC (10, 15, 20, 25, 30, and 35 ppm) and determine which achieved the highest turbidity removal in raw water. The results from 11 trials indicated that the optimal PAC dosages fell within the range of 15 to 25 ppm, aligning with the prescribed standards for turbidity, color, and pH as per the NTE INEN 1108:2020 Standard. These findings enabled the development of an optimal dosing curve, following a logarithmic regression model with a coefficient of determination of 65.75%. Additionally, it was determined that the most influential parameters affecting turbidity removal percentage were the initial turbidity level and the applied PAC dosage. Response surface methodology confirmed that as raw water turbidity increases, higher removal percentages are achieved, and the PAC dosage also increases, consistently staying within the 15 to 25 ppm range.