Use of electrochemical processes and their combinations with biological processes for sanitary landfill leachate treatment - Literature review
Landfill leachates contain several types of organic and inorganic pollutants that can contaminate aquatic environments if they are not treated in an appropriate way. In recent years, there has been an increase in the use of electrochemical processes for the treatment of landfill leachates, with satisfactory results. Some advantages related to the use of electrochemical processes are: small space requirement, short treatment time, low requirements of chemical reagents and easy automation. The ability to remove biorefractory compounds and to increase the biodegradability of the effluent makes them interesting methods for the treatment of landfill leachates. In the present literature review, particular attention is paid to three electrochemical processes commonly used for the treatment of landfill leachates, namely Electro-Oxidation (EO), Electro-Fenton (EF) and Electro-Coagulation (EC). For each of them, we elucidate the different parameters that affect treatment efficiency. Generally, electrochemical processes are influenced by the applied current density, type of electrode, distance between electrodes, treatment time, pH and effluent conductivity. The combination of electrochemical processes with biological processes is also considered. The integration of these two processes improves the treatment efficiency for landfill leachates and reduces the cost and treatment time. However, further studies are required in order to optimize the combined method and to clarify the influence of biological treatment on the electrochemical treatment, and vice versa.