The simultaneous removal of turbidity and humic substances from water using the enhanced coagulation process

Abstract

This study aimed to investigate the efficiency of the enhanced coagulation (EC) process for the simultaneous removal of turbidity and humic substances (HS) from raw water from the Sanandaj Water Treatment Plant (SWTP). This study was conducted on a laboratory scale using a jar test device and ferric chloride (FeCL₃) as the coagulant. Accordingly, the effects of pH and coagulant dosage variations on the simultaneous removal efficiency of turbidity and humic substances in the enhanced coagulation process were investigated. Furthermore, certain parameters including the total organic carbon (TOC), dissolved organic carbon (DOC), ultraviolet absorbance (UV₂₅₄), and chemical oxygen demand (COD) were determined as the indices of the humic substances and turbidity in the water samples. The results of the raw water analysis showed that the mean values of TOC, DOC, UV₂₅₄, COD, and turbidity parameters were 4.41 mg/L, 4.11 mg/L, 16.47 1/cm, 15 mg/L, and 4.37 NTU, respectively. Moreover, the results of the present study showed that the average efficiency of the enhanced coagulation process in the removal of TOC, DOC, UV₂₅₄, COD, and turbidity was 65%, 62%, 70%, 69%, and 93%, respectively. Accordingly, the EC process using FeCL₃coagulant is a suitable, cost-effective, and highly efficient method for the simultaneous removal of turbidity and humic substances from water. Furthermore, this process can be used as an applicable method in SWTP as well as in other similar water treatment plants.