Abstract
The combined sedimentation-chemical oxidation treatment of medium-stabilized landfill leachates has been investigated. The sequence of stages implemented was: (a) coagulation–flocculation by pH decrease (pH 2) to acidic conditions (COD removal ≈ 25% related to COD 0 ≈ 7500 ppm); (b) coagulation–flocculation by Fe(III) addition (0.01 M) at pH 3.5 (COD removal ≈ 40% related to COD of supernatant after step (a); (c) Fenton (Fe(III) = 0.01 M; H 2O 2 = 1.0 M) oxidation (COD removal ≈ 80% related to COD of supernatant after step (a); and (d) coagulation–flocculation of Fenton's effluent at pH 3.5 (COD removal ≈ 90% related to COD of supernatant after step (a). The use of Kynch theory allows for the design of clarifiers based on the amount of solids fed. For a general example of 1000 m 3 day −1 of a feeding stream, clarifier area values of 286, 111 and 231 m 2 were calculated for compacting indices of 3.7, 2.67 and 2.83 corresponding to the first, second and third consecutive sedimentation processes, respectively, (steps (a), (b) and (d)).
Published Version
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