Removal of COD from landfill leachate by an electro/Fe2+/peroxydisulfate process

• An electro/Fe2+/peroxydisulfate process was used to remove COD from landfill leachate.
• An empirical correlation between persulfate concentration and COD value was obtained.
• COD removal by oxidation and coagulation was quantitatively determined.
• Effects of pH0, current density, Fe2+ and PDS dosage on COD removal were investigated.
• 62.2% COD was removed at 60 min, [PDS]:[Fe2+] = 62.5 mM:15.6 mM, pH 3 and j = 13.89 mA/cm2.

Electrochemical method was used to enhance COD removal during treatment of landfill leachate by ferrous ion activated peroxydisulfate (PDS) process. The contribution of oxidation and coagulation to COD removal was quantitatively determined. The effects of initial pH, current density, PDS and ferrous ion dosage on COD removal were investigated. The COD removal by oxidation increased with PDS concentration and current density, but decreased with initial pH. There existed an optimal Fe2+ dosage for the oxidative degradation of leachate. The COD removal by coagulation increased with Fe2+ dosage, but decreased with current density. The overall COD removal efficiency was significantly improved with respect to ferrous ion activated PDS process.