Removal of color and turbidity of waters containing natural organic materials using integrated enhanced coagulation and direct filtration

Surface waters are often included numerous dissolved and suspended impurities. Smaller particles called colloids are removed after coagulation and flocculation. The aim of this study was to evaluate the efficacy of the combination process of advanced coagulation and direct filtration to remove color and turbidity from surface waters.
This experimental study was done in pilot scale with a capacity of 144 L/h. Both, color and turbidity were evaluated in this research. Water samples were collected from Choghakhor wetland, which located about 65 km of Shahrekord. The color and turbidity was measured using spectrophotometer. Taguchi method was used for data collection. In this study, the effects of pH, coagulant dose of ferric chloride (FeCl3) and input flows on removing color and turbidity were examined.
The results showed that the optimum conditions for the removal of color was around 96% (i.e. color reduced from 140 TCU to 5.3 TCU. Initial turbidity was removed more than 95% (i.e., from 32 NTU to 1.4 NTU). The optimum conditions pH for color and turbidity removal were obtained at pH 6.2, Chloroferric dose of 40 mg/L, and flow rate 95 L/h. Based on the analysis of the factors examined, pH has the greatest influence on the removal of contaminants and the concentration of coagulants and debbie were next in ranking.
The combined Process of advanced coagulation can improve the efficiency of water refinery by remove the colors and turbidity with direct filtration.