Landfill Leachate Treatment by Combining Coagulation and Advanced Electrochemical Oxidation Techniques

Abstract

This paper presents and discusses the results obtained in the treatment of raw landfill leachate (RLL) with a combination of coagulation-flocculation (Alum) and electrochemical techniques, using a filter-press reactor with a boron-doped diamond electrode. The success of the treatment was demonstrated by the quality of the treated water, which was evaluated based on parameters such as color, odor, turbidity, chemical oxygen demand, biochemical oxygen demand, free and total chlorine, total nitrite and nitrate, ammonia and microbiological tests (mesophiles and termotolerant coliforms). The best conditions for coagulation-flocculation involved a dosage of 20 mL/L Al 2 (SO 4 ) 3 (50 g/L) at pH 6.0. To reduce energy consumption, the electrochemical treatments were carried out by applying different limiting current density (i lim ) step sequences. This strategy reduced the energy consumed in the removal of the organic load by up to 40 % while maintaining a similarly effective mineralization rate (> 90 % COD removal) between the steps. Microbiological tests revealed that the number of mesophiles was more than twelve orders of magnitude lower after electrolysis, indicating the important sanitizing effect caused by the HClO/chloramine species generated in the process. Color, turbidity and ammoniacal nitrogen were completely eliminated from the treated leachate by the end of the electrolysis process.[a] M.

Electrochemical removal of Bisphenol A from landfill leachate under Nordic climate conditions

“…Several studies investigated the performance of EO to remove common wastewater parameters form landfill leachate (LL). For instance, Panizza et al [2] successfully removed chemical oxygen demand (COD) from LL to below the disposal limit (160 mg L −1 ) and de Oliveira et al [3] reported a COD removal of 90% or higher. Satisfactory removal of ammonium nitrogen (NH 3 -N) from LL of up to 100% by EO has been reported by Li et al [4].…”

Pre-coagulated landfill leachate treatment by Electro-oxidation using MMO/Ti, Pt/Ti, and graphite anodes

“…Among the advanced oxidation processes, the electro-oxidation (EO) process is an effective process that can be applied at standard conditions. Recently, applications of advanced EO processes have drawn attention especially in the removal of resistant organic compounds [11][12][13]. The EO processes are based on in situ electrogeneration of hydroxyl radicals, which is a strong oxidant that does not show selective behavior.…”

“…In the literature, there are combined process applications as well as stand-alone EO processes in leachate treatment. The other component of the combined processes in which EO is applied as pre or post-treatment can be biological, physical, or chemical applications [13,[30][31][32]. In the study conducted by Gilvapas et al [30], the coagulation process was applied before the EO process using BDD anode, and 93.5% COD removal efficiency was obtained.…”

“…In the study conducted by Gilvapas et al [30], the coagulation process was applied before the EO process using BDD anode, and 93.5% COD removal efficiency was obtained. Oliviera et al [13] applied EO to the raw leachate following the coagulation process. In the sequential process, Al 2 (SO 4 ) 3 was used as the coagulant and the BDD electrode was used and over 90% COD removal was achieved in the process output [13].…”

“…Oliviera et al [13] applied EO to the raw leachate following the coagulation process. In the sequential process, Al 2 (SO 4 ) 3 was used as the coagulant and the BDD electrode was used and over 90% COD removal was achieved in the process output [13].…”