Electrochemical oxidation treatment of reverse osmosis concentrated landfill leachate: Effect of operation parameters and evolution of dissolved organic matter

•DOM in ROCLL includes BP (>18 kDa), HS (0.45–18 kDa) and LMWS (<0.45 kDa) fractions.•RSM experiments showed that pH was the most critical parameter for EO treatment.•Removal of DOC fractions was controlled by charge transfer process.•Elimination of chromophores and fluorophores was limited by mass transport process.•BP-C1, HS-C2 and LMWS-C1 subfractions required further treatment after EO process.