Electrochemical Advanced Oxidation Processes Treatment of Landfill Leachate

Mar 19, 2021

What is advanced electrochemical oxidation?
Electrochemical advanced oxidation processes (EAOPs) have been developed for the treatment of environmental pollution, especially focusing on water streams. EAOP can generate a very powerful oxidizing agent hydroxyl radical (•OH) in solution, this hydroxyl radical destroys organics up to their mineralization. EAOPs include heterogeneous processes like anodic oxidation and photoelectrocatalysis methods, in which •OH are generated at the anode surface either electrochemically or photochemically, and homogeneous processes like electro-Fenton, photoelectro-Fenton, and sonoelectrolysis, in which •OH are produced in the bulk solution.

Is it effective for landfill leachate?
Landfill leachate possesses high concentrations of ammonia, micropollutants, and heavy metals, and is characterized by low biodegradability. It is a significant threat to groundwater and surface water sources.
The electrochemical advanced oxidation process allows most of the recalcitrant pollutants to be oxidized effectively within an easy operational and acceptable retention time, without the need to provide additional chemicals, and without producing waste materials. It is efficient for leadfill leachate treatment.
What is important for advanced electrochemical oxidation of landfill leachate?
The basic set-up of an electrochemical oxidation unit comprises a cathode and an anode, a direct current power supply, and an electrolyte. The electrochemical oxidation of landfill leachates can be categorized into two types: direct oxidation, in which species are oxidized at the anode, and indirect oxidation, in which the oxidation is carried out by secondary species (such as chlorinated compounds) originated at the electrodes.
The anode material is of primary importance in reactor design, as it should be characterized by high stability, low corrosion, low cost, and exhibit high activity toward pollutant oxidation and low oxygen evolution.
Electrodes that have been used for the electrochemical oxidation of landfill leachates are PbO2, MMO (Ti/RuO2-IrO2), and boron-doped diamond (BDD), Sb-doped SnO2, etc. Each of them possesses excellent performance in certain conditions.