Although the sCOD removal efficiency was ∼93%, the stabilised
leachate still contained ahighresidual sCOD content(∼5.6 g/L). This
recalcitrant DOM most likely consisted of humic compounds such
as humic and fulvic acids [26]. The recalcitrant DOM appeared similar
in both reactors. The effect of metal complexation with dissolved
organic matter is discussed in Section 3.5.