Performance of a novel granular activated carbon and gravity-driven membrane hybrid process: Process development and removal of emerging contaminants

In this study, a novel granular activated carbon (GAC) gravity-driven membrane (GDM) hybrid system with a ceramic membrane was developed for the production of high quality water. The operational performance in water permeability; removal of organic matter; and contaminants of emerging concern (CECs) including microplastics, larvae, and perfluorinated compounds (i.e., perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid(PFOS)) was evaluated. The experimental results indicate that the GAC-GDM hybrid system can overcome the limitations of the GAC (i.e., low rejection efficiency of particulates) and GDM (i.e., low rejection efficiency of organics) processes. The GDM process showed higher removal rates of microplastics and larvae than the GAC process (i.e., 77.9 and 100% vs. 16.6 and 70%, respectively), and the GAC process exhibited higher removal rates of organic matter and perfluorinated compounds (PFOA and PFOS) than the GDM process (i.e., 54.8, 90.9 and 99.1% vs. 17.6, 23 and 31.8%, respectively). In the GAC-GDM hybrid system, stable water flux was observed with the efficient removal of CECs and organic matter during operation. This study implies that the GAC-GDM system can be used as a distributed water treatment system in remote areas such as islands and mountains because the GAC-GDM system is able to minimize the operation scale.