Removal of metals from landfill enriched-leachate with electrolytic process

In this study, electrolytic processes were used to treat enriched-leachate. The characteristic of the enriched-leachate contains refractory pollutant for low BOD/COD ratio, metals (Cr, Cu, Zn, Pb....) and chloride (12700 mg/L). The overall plan of electrolytic process included electrolytic oxidation and electrolytic foam separation with chelating surfactant S₄₀ (Sodium dimethyl dithiocarbamate). In electrolytic oxidation, chloride was used as supporting electrolyte to produce strong oxidant (Cl₂/HClO) that could oxide refractory organics by indirect oxidation effect. The experimental results showed that the deep-brown color of enriched-leachate became light-yellow in 6 hours operation time by electrolytic oxidation, the COD removal of leachate was 54% under a current density 5.0 Amp./dm². In addition a sequent electrolytic foam separation was used to separate metals from leachate. When the chelating surfactant to metals (S/M) ratio equaled to 1 and after 10 minutes flotation, removal of total metals were over 93%.