Parallel study on removal efficiency of pharmaceuticals and PFASs in advanced water treatment processes: Ozonation, GAC adsorption, and RO processes

Choe, Hyun-Seok; Kim, Ki Yong; Oh, Jeong-Eun; Kim, Jae-Hyuk

doi:.0..

DOI: https://doi.org/10.4491/eer.2020.509

Parallel study on removal efficiency of pharmaceuticals and PFASs in advanced water treatment processes: Ozonation, GAC adsorption, and RO processes

Hyun-Seok Choe¹, Ki Yong Kim², Jeong-Eun Oh¹, and Jae-Hyuk Kim¹^†

¹Department of Civil and Environmental Engineering, Pusan National University, Busan 46241, Republic of Korea
²Food Safety and Processing Research Division, National Institute of Fisheries Science (NIFS), Busan 46083, Republic of Korea

Corresponding Author: Jae-Hyuk Kim ,Tel: +82 51 510 2312, Email: jaehyuk.kim@pusan.ac.kr

Received: September 15, 2020; Accepted: December 15, 2020.

ABSTRACT

We aimed to assess the removal efficiencies of four pharmaceuticals (carbamazepine, crotamiton, metformin, and sulfamethoxazole) and four poly- and perfluoroalkyl substances (PFASs) (PFHxA, PFHxS, PFOA, and PFOS) by lab-scale ozonation, granular activated carbon (GAC) adsorption, and reverse osmosis (RO) membrane processes under varying operating conditions. Ozonation and GAC adsorption processes were conducted at two temperatures (5 and 25°C) and three pH conditions (3, 7, and 11). The membrane process was performed using an unstirred cell with two different RO membranes. The most pharmaceuticals were effectively removed by ozonation, whereas metformin and PFASs were unaffected due to their stable chemical structures. In the GAC process, metformin was hardly removed under acidic conditions but it was enhanced by over 90%. PFASs were effectively removed by GAC adsorption and RO membrane processes. The RO membrane for brackish water treatment showed higher rejection than that for residential water treatment. Moreover, the rejection of PFAS increased as the molecular weight increased. A strategy was found to effectively remove the remaining metformin in most advanced water treatment processes. Chemically persistent PFASs were hardly removed by the ozonation process but were effectively removed by physical treatments such as GAC adsorption and RO membrane processes.

Keywords: GAC adsorption process | Membrane process | Ozonation process | Perfluoroalkyl substances | Pharmaceuticals