Characterization and treatment of landfill leachates by electro-Fenton process: A case study in Algeria.

Abstract

The feasibility of the electro-Fenton (EF) process to improve the biodegradability of Algerian leachates was examined, in order to prepare this kind of flux for conventional biological treatment. This work also included, for the first time in Algeria, the control and monitorization of a landfill-the "Hamici" landfill. Several physicochemical parameters were determined allowing its classification into an intermediate degradation phase, namely considering their alkaline pH (8.7), high ammonium concentration (3,120mg/L), low content in heavy metals, and biodegradability (BOD5 /COD=0.22). The effects of important parameters such as current intensity, treatment time, and temperature on COD removal have been studied and optimized by using response surface analysis of a central composite design, where 91.1% of COD was removed with a treatment time of 285min, a current intensity of 3A, and a temperature of 20°C. A biodegradability test, which was performed on a solution electrolyzed with 120min, 2A, and 20°C, allowed to improve the leachates biodegradability from 0.2 to 0.42, with a removal rate of COD and TOC of 53.35% and 34.5%, respectively. However, the current efficiency declined from 137% to 76.6% when the current intensity was rise from 0.5 to 2A. These results showed the relevance of EF process applied on raw intermediate leachates and its possible benefit in the Algiers leachates treatment processes. Thus, it was concluded that biological treatment can be combined with EF process for optimal mineralization of leachates with clear advantages in this studied location. PRACTITIONER POINTS: Characterization and treatment of leachates by electro-Fenton (EF) process were carried out. The leachates are intermediate type and therefore biologically recalcitrant. The operating parameter for EF process were modeled and optimized by the central composite design. Current intensity of 2A reduces COD and TOC of 53.35% and 34.5%, respectively. The ratio BOD5 /COD increased from 0.2 to 0.42 after 120min of electrolysis time.