Photocatalytic degradation of the landfill leachate containing refractory matters and nitrogen compounds

Photocatalytic process was applied to the landfill leachate containing non-biodegradable matter for which biodegradability (BOD/COD) was relatively low. The variations of concentration, apparent first-order rate constants (k′), and removal efficiency were used to describe the degradation behavior of landfill leachate under different conditions, which were various initial pH and photocatalyst concentration. Under the acidic condition, the photocatalytic removal efficiency of landfill leachate was relatively high because there was very low concentration of inorganic carbons that could inhibit the photocatalytic oxidation. To remove ammonium–nitrogen, the photocatalytic reaction must be operated in neutral and/or alkaline solution, and the contribution of photocatalyst in diminution of ammonium–nitrogen might be negligible. The effect of TiO2 concentration was obtained from experimental results and it could demonstrate the relationship of amounts of TiO2 dosage and reaction rate.