Fuel station effluent treatment by electrochemical technology

• Different performances depending on the electrocatalytic properties of the anode material
• Distinct oxidants electrogenerated as a function of the couple material–electrolyte.
• Fast almost total removal of TPH and BTEX in sulfate medium by EO with Ti/Pt
• Larger total oil and greases reduction by electroflotation promoted by gas evolution

In this work, a real effluent from oil–water separator of fuel station has been treated for the first time by electrochemical oxidation (EO) process. Electrochemical experiments were carried out under real discharged effluent conditions using Ti/Pt and Ti/IrO2–Ta2O5 anodes at different supporting electrolytesin order to study the influence of the different oxidants electrogenerated. The effect of applied current densities (j = 10, 20 and 30 mA cm− 2) was also evaluated. Results showed that good performances were achieved using Ti/Pt anode adding K2SO4 as supporting electrolyte to improve the solution conductivity. Dissolved organic carbon (DOC) and chemical oxygen demand (COD) abatements of 55.2% and 61.5% were achieved, reducing significant concentration of organic compounds (in terms of benzene–toluene–ethylbenzene–xylene (BTEX) and total petroleum hydrocarbons (TPHs)) at j = 30 mA cm− 2 after only 4 h of electrochemical treatment. Affordable costs of process expenditure of US$ 3.79 m− 3 were also achieved using Ti/Pt anodes; however, these costs could be reduced increasing the solution conductivity. The figures obtained in this investigation provide valuable information for developing of electrochemical technologies to their real application in order to propose a pre or post treatment alternative.