Application of double filtration with activated carbon for the removal of phenols in drinking water treatment processes

The primary source of the discharge of phenols into the environment is industrial activity, such as the production of pharmaceuticals, plastics, and pesticides, being the majority discharged into surface water sources, reaching concentrations around 0.001 to 0.400 mg/L. These compounds are considered a priority contaminant due to their toxicity to aquatic life and effects on human health. The presence of phenols even at low concentrations generates flavour and odour in drinking water. Due to the molecular stability and solubility of phenols in water, their removal by conventional water treatment methods is inefficient. However, adsorption with granular activated carbon (GAC), after conventional filtration with sand and anthracite, is an efficient technique for the reduction of organic compounds such as phenols. This paper studied the effect of applying double filtration to the reduction of phenols present in the filtered water of a conventional drinking water treatment plant, using two types of GAC (vegetable and mineral) and three GAC:Sand configurations (100:00; 00:100; 50:50). The configurations with GAC showed an efficient reduction of turbidity, organic matter indicator variables (UV254 absorbance and total organic carbon) and phenols, the mineral GAC being the most efficient GAC.