Experimental evaluation of microfiltration–granular activated carbon (MF–GAC)/nano filter hybrid system in high quality water reuse

Abstract

In order to achieve high quality water reuse, a dual membrane hybrid system (combining microfiltration– granular activated carbon (MF–GAC)) adsorption hybrid system followed by nanofiltration (NF)) was used. This system's performance was evaluated in terms of organic matter, pharmaceuticals and personal care products (PPCPs), and removal of inorganic matter. Biologically treated sewage effluent (BTSE) collected from a water reclamation plant in Sydney, Australia was used as the water source. The removal efficiency of dissolved organic carbon (DOC) of MF–GAC strongly depends on the dose of GAC and filtration flux. MF–GAC system effectively removed hydrophobic organics (45–80%) as well as hydrophilic organics (50–80%). The removal of various PPCPs ranged from 33% to 92%, and as expected, the amount of inorganic matter removed by the MF–GAC system was very small. Hence, the NF system, as a second membrane system, was employed to polish the effluent from the MF–GAC hybrid system. The NF system rejected most of DOC (495%), sulfates (99%) and a substantial amount of calcium (70%), and magnesium (60%) from MF–GAC effluent. Further, more than 90% of PPCPs were removed by the NF system. Overall the dual membrane hybrid system proved to be very effective in removing organics, PPCPs and inorganic matter. The MF–GAC followed by NF results in high quality water reuse and this system can serve as an effective treatment option for water reuse schemes.