Electrochemical Treatment of Landfill Leachate:  Oxidation at Ti/PbO₂ and Ti/SnO₂ Anodes

Abstract

Leachate originating in landfills where municipal solid wastes are disposed is a wastewater with a complex composition that could have a high environmental impact. The primary goal of this research was to investigate the feasibility of removing refractory organic pollutants and ammonium nitrogen from landfill leachate by electrochemical oxidation. The effects of current density, pH, and chloride concentration on the removal of both chemical oxygen demand (COD) and ammonium nitrogen were investigated. Titanium coated with lead dioxide (PbO 2 ) or tin dioxide (SnO 2 ) was used as the anode. An effective process was achieved in which the leachate was decolorized, COD was removed up to a value of 100 mg L -1 , and ammonia was totally eliminated. Average current efficiency of about 30% was measured for a decrease of COD from 1200 to 150 mg L -1 , while efficiency of about 10% was measured for a near complete removal of ammonium nitrogen, starting from an initial value of 380 mg L -1 . Results indicated that the organic load was removed by both direct and indirect oxidation. Indirect oxidation by chlorine or hypochlorite originating from oxidation of chlorides is believed to be mainly responsible for the nitrogen removal.

Removal of Organic Matter from Landfill Leachate by Advanced Oxidation Processes: A Review

“…However, there are two drawbacks of electrooxidation which may limit its wide application for landfill leachate treatment, one is high energy consumption, and the other is potential for formation of chlorinated organics. Especially because of its expensive operating costs compared with other available technologies (for example, biological processes), electro-oxidation will be favored as a finishing step in a combined process or an auxiliary unit in emergency situations, instead of a full treatment for landfill leachate [65].…”

Traitement des effluents d’abattoir de viande rouge par électrocoagulation-flottation avec des électrodes en fer

“…À 4 V, 27,5 % d'azote total est éliminé. L'abattement maximal est 76,2 % à 12 V. L'azote est aussi éliminé sous forme inorganique par oxydation des ions NH 4 + et formation des chloramines et d'azote gazeux (CHIANG et al, 1995) et (COSSU et al, 1998) (cité par LABANOWSKI,2004.…”

Anodic Materials with High Energy Efficiency for Electrochemical Oxidation of Toxic Organics in Waste Water

“…Only few papers dealt with real waste water such as landfill leachate (Cossu et al, 1998), tannery waste, dye plant effluents etc (Ciriaco et al, 2009). However, due to the complex composition of the real waste water, the mechanism for organic compounds oxidation was difficult to discuss.…”

“…They also investigated the bisphenol A degradation on tin dioxide anode (Cui et al, 2009b). Cossu et al (1998) investigated landfill leachate oxidation on SnO 2 and PbO 2 anodes, respectively. Tin dioxide electrode showed similar performance as the PbO 2 .…”