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

Abstract

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.

Filtration Process and Alternative Filter Media Material in Water Treatment

“…Then, dual media filters with sand and GAC have been researched to remove both particles and organic contaminants [66,67]. A recent work [68] examined the effect of applying dual media configured filtration to the reduction in phenols in a conventional drinking water treatment plant, using two types of GAC (vegetable and mineral) and three GAC/Sand configurations (1/0; 0/1; 0.5/0.5). The configurations of filters can be seen in Table 3.…”

“…Configurations used for the evaluation of sand-GAC filtration. (reprepared using the data from [68]). The study reveals that the dual filters with sand and GAC ensured better removal of TOC and phenols.…”

“…Residual concentration of contaminants in the filtrate over time for all filter configurations. (a) TOC, raw water TOC concentration = 3.369 mg/L; (b) phenol, raw water phenol concentration = 245.3 µg/L (reprepared using the data from [68]).…”

Study of Water Filtration Without Chemical Pre-Treatment

“…All these operate in slow sand filtration, but to a far lesser extent flow with rapid sand filtration. However, with slow sand filtration, there is the additional purification process of biological activity (Fuentes-López et al, 2018;Tan et al, 2013). As a filter goes to operation at the beginning of a fresh water run, as a result of settlement from the water and straining at the sand surface the accumulation of a layer of alluvial mud, organic waste, bacterial matter, algae, etc.…”