Treatment of oil effluents by microbial electrolysis cell (MEC) method in comparison with activated sludge process (ASP)

Due to the increasing demand and globalization of the use of oil resources and other energy sources, the production of petrochemical wastewater has been increased, so that in ۲۰۱۶ the production rate of oil wastewater was reported ۵.۰۶ × ۱۰۷ t/d. Discharge of these wastewater without elimination of hydrocarbons is dangerous for the environment. Therefore, efficient treatment of petrochemical wastewater is necessary to overcome the challenges that arise. In addition, water management is necessary. Currently, physicochemical (Physical-chemical) methods are commonly used to treat petrochemical wastewater that have limitations such as high investment, high operating costs, production of hazardous sludge, and saline solutions, as well as the need for skilled labor. These disadvantages lead to increased attention to the use of biological methods. The biological methods used are Activated Sludge process (ASP) and Microbial Electrochemical Techniques (MET). METs can simultaneously treat wastewater and produce useful products. One of the types of METs is Microbial Electrolysis Cells (MEC). Unlike ASP, Microbial Electrochemical Techniques don’t require much ground and aeration and are cheaper, they also don’t produce odors. In this study, the performance of Activated Sludge Method with Microbial Electrolysis Cell against oil wastewater was investigated. To do this, ۳۰% (volumetric / volumetric) of wastewater was added to the BHI medium, one in ASP mode and the other in Single-Chamber Microbial Electrolysis Cell (SMEC) with voltage of ۰.۸ v, and the chambers were filled with a mixture of N۲/CO۲ gases. After ۴۸ hours,the environment at MEC was clearer and contained more sediment. The use of METs is more efficient than the ASP method because the elimination process is done more and the technique has the potential to produce valuable products such as electricity and hydrogen and methane gases.