Optimización procesos de floculación y sedimentación con un diseño factorial tratando agua del embalse de Teatinos

Abstract

The water treatment plant (WTP) of Tunja, Boyacá provides drinking water for a population of approximately 172,548 in habitants. The WTP treats a flow rate of 230 L/susing processes of aeration, coagulation, flocculation, sedimentation, filtration, anddisinfection. However, the raw water physicochemical characteristics of the Teatinosreservoir makes difficult its treatment using coagulation, flocculation, and sedimentationdue to its low alkalinity (4 – 6 mg/L as CaCO3) and relatively low pH (5,7 – 6,3). Theobjective of this research was to optimize the flocculation and the sedimentation processfor turbidity removal at the laboratory level using a regular jar tester and a factorialdesign. The factorial design allowed to assess three different velocity gradients (G) inflocculation, or slow mixing (10, 50 y 100 s-1), three different flocculation times (FT)(10, 15 y 20 min.), and three different sedimentation times (ST) (20, 30 y 40 min.),respectively, and their impact on turbidity removal. The results showed that the optimaloperational conditions in the jar test were: (G= 100 s-1, TF = 20 min. y TS = 20 min.),respectively for obtaining a residual turbidity of 0,77 UNT, which correspond to 78% ofturbidity removal. In addition, it was possible to predict final turbidity values of 0,20UNT in the jar test using a surface response methodology, the low turbidity valuecorresponds to operational parameters of (G=78 s-1, TF= 23 min. y TS = 30 min.),respectively.