Post-treatment of stabilized landfill leachate by upflow gravel filtration and granular activated carbon adsorption.

Stabilized leachates from sanitary landfills generally display high levels of recalcitrant organic matter, sometimes requiring a combination of biological and physicochemical treatment processes. This study evaluated the post-treatment by Upflow Gravel Filtration (UGF) followed by Granular Activated Carbon Adsorption (GACA) on a pilot scale of two different landfill leachates previously treated by biological processes. The system design was proven technically feasible for a continuous flow post-treatment in relation to recalcitrant organic matter removal efficiency. The UGF experiments presented 83.9% and 82.0% COD removals for leachates A and B, respectively, with residual values of 107 and 194 mg L-1. The UGF-GACA experiments, in turn, produced effluents with residual COD values of 67 and <60 mg L-1 for leachates A and B, respectively, corresponding to 89.9% and >94.6% efficiencies.