Investigating the Potential of Electro-coagulation-Flotation (ECF) Process for Pollutants Removal from Olive Oil Mill Wastewater

Olive oil mill wastewater (OOMW) is a liquid odorous that contains turbidity and organic materials and emulsion oils. More than 30 phenolic compounds were detected in OOMW. The toxicity of OOMW due to phenol compounds is 1000 times more than toxicity of municipal wastewater. Thus, the discharge of wastewater without purification can created problems for the environment. Different methods for OOMW treatment were tested, but none of them is economical and hasn’t ideal efficiency. Electrocoagulation–Flotation (ECF) using sacrificial anodes extensively has been used to remove different compounds from water and wastewater. This research is performed on olive oil mill natural wastewater in the laboratorial scale bath electrochemical reactor with 1750 ml useful volume. ECF reactor was consists of an uncovered Plexiglas chamber with pairs of metal sheets called electrodes, that are arranged in pairs of two-anodes and cathodes, the cathode is titanium and anode is commercial iron which they were arranged with a same distance alternately, and they were connected to the direct current power source by parallel monopolar mode. Experiment was performed with 39.06, 78.125 and 117.187 A/m2 current density; in the natural wastewater pH (pH=5.2), neutral pH (pH=7) and alkaline pH (pH=10). The maximum efficiency for all pollutants was obtained at maximum applied current density in the natural pH of wastewater (pH = 5.2). In this manner, by using 117.187 A/m2 current density in the natural pH of the wastewater after 60 minutes, the efficiency for turbidity, chemical oxygen demand (COD) and phenolic compounds were 99.89%, 96.14%, 89.97% respectively. According to the gained findings, Efficiency treatment electro-coagulation-flotation process for olive oil mill wastewater in natural pH (pH = 5.2), promises the ability this process for olive oil mill wastewater treatment that its pH between 4.5 to 5.5 normally.