A NOVEL HYBRID ELECTRO-COAGULATION/ FORWARD OSMOSIS MEMBRANE SYSTEM FOR TREATMENT OF PRODUCED WATER

Abstract

Large volumes of fresh water are consumed in the process of oil and gas exploration, producing even larger volumes of highly contaminated produced water (PW) which exhibits a major environmental problem. This work investigates the application of a novel hybrid system by combining electro-coagulation and forward osmosis (FO) for the treatment and reclamation of PW. Electro-coagulation was applied at three different current densities 10, 30 & 60 mA/cm2 for 10 and 30 minutes. Following that, the treated produced water was further treated by Forward Osmosis (FO) using polymeric membrane. Two orientations of the membranes (active layer facing draw solution and active layer facing feed solution) and three flow rates 0.8, 1.2 and 2 LPM were applied. By applying electro-coagulation, the optimum water quality was obtained after 10 minutes run time, at a current density of 10 mA/cm2. Electro-coagulation achieved 91 and 97% removal of total organic carbon (TOC) and oil and grease (O&G), respectively. FO used in pressure retarded osmosis (PRO) mode achieved the highest flux at a flow rate of 1.2 LPM and reduced the PW conductivity to 16%. Overall, the hybrid system attained a total of 99% removal of total suspended solids (TSS). The obtained improved water quality suggests a high potential of practicability of the applied hybrid system in the treatment and reclamation of PW.