Sustainable management of saline oily wastewater via forward osmosis using aquaporin membrane

Abstract

The hypothesis that petrochemical oily wastewater containing high amounts of total dissolved solids (TDS), chemical oxygen demand (COD) and total organic carbon (TOC) can be effectively treated by a new biomimetic forward osmosis (FO) membrane for fertigation purposes was assessed. The biomimetic FO membrane was characterized, and its intrinsic properties were evaluated. The fertilizer-driven FO (FDFO) process was evaluated in terms of water flux (WF), reverse solute flux (RSF), specific RSF (SRSF), and oil rejection at various draw solution (DS) concentrations and cross-flow velocities. Under optimized conditions, deionized water was used as feed and 3 M KCl, the most widely used potassium fertilizer, was used as DS at a cross-flow velocity of 0.1 m·s−1. WF and RSF of 67.22 Lm-2 h−1 and 48.3 gm−2 h−1, respectively, were obtained. Using saline oily wastewater as the feed, the orientation of the feed facing the membrane support layer exhibited a lower WF due to oily layer fouling within the membrane support. Apart from almost complete rejections of organic chemicals, the biomimetic FO membrane demonstrated a better performance (WF = 11.31 Lm−2 h−1) than the typical polyamide thin film composite (TFC) membrane (WF = 5.23 Lm−2 h−1) during mid-term fouling tests. This study demonstrates that FO process is an effective strategy for sustainable management of hazardous petrochemical oily wastewater by recycling the diluted fertilizer solution for direct fertigation without further treatment.