Pilot plant study of the electrooxidation of landfill leachates using BDD anodes
Advancing the chemical engineering fundamentals
Electrochemical Engineering - II (T2-14b)
Keywords: Electrooxidation, landfill leachate, pilot plant, BDD
Adelaida Cabeza, Ana María Urtiaga, Inmaculada Ortiz
Dept. Chemical Engineering and Inorganic Chemistry, ETSII y T, University of Cantabria, 39005, Santander, Spain
The aim of this work is the building and starting up of a pilot plant designed for the electrooxidation of leachates from a municipal landfill site, being the high loading of ammonium and COD and the poor biodegradability the main characteristics of this wastewater.
The viability of the electrochemical oxidation process in order to treat leachates from a municipal landfill site was studied in a previous work. Viability experiments were performed by using a single-compartment cell. Boron doped diamond on silicon (BDD) was used as anode and stainless steel (SS) as cathode, both electrodes with a surface area of 70 cm2 each. Excellent COD and ammonium removal efficiencies were obtained after six hours of electrochemical process, leading to treated leachates with COD and N-NH4+ concentrations below disposal limits, 160 g L-1 and 15 mg L-1 respectively. Moreover, kinetics of COD and ammonium oxidation were mathematically modelled (Cabeza et al., 2006).
According to the laboratory scale results, a pilot plant with 30 L h-1 of treatment capacity has been designed and built. The unit has 150 electrochemical compartments set up in three parallel ways with 10 cells. Each compartment has a BDD anode and a SS cathode, both electrodes with a surface area of 70 cm2. Hence, the total anode surface area is 1.05 m2. The electrical current is provided by three power suppliers 750 A, 16 V DC. The leachate is stored in a tank of 700 L and it is pumped through the cells (61 L/min cell) in closed circuit.
At the moment, similar experiments are being carried out in both laboratory and pilot plant scales in order to determine the reliability of the COD and ammonium models previously developed in laboratory scale. It is foreseen to continue with an optimization of the electrooxidation process. The overall results of the pilot plant would allow the dimensioning of the industrial scale treatment plant with the definition on investment and operating cost.
Acknowledgements
Financial support of projects MMA 2.5-216/2005/3-B, PET2005_0169 (MEC) and MARE is gratefully acknowledged.
References
Cabeza, A., Urtiaga, A., Ortiz, I. Electrochemical Treatment of Landfill Leachates using a BDD Anode. 2006. Accepted for publication in Industrial & Engineering Chemistry Research.
Presented Wednesday 19, 11:20 to 11:40, in session Electrochemical Engineering -II (T2-14b).
