Oprimisation of Organic Matter Removal from Landfill Leachate Using Ferrous (II)/ Persulfate, (PS) System / Nabilah binti Samsul

submitted in fulfilment of the requirements for the degree of Master of Science (by Research)

Abstract

Fe (11) activated Persulfate (PS) enhanced with reducing agents (Hydroxylamine (HA) and Ascorbic acid (AA)) was selected in this study for landfill leachate treatment. Two sets of laboratory-scale experiments were conducted, which were PS+ Fe (II)+ НА and PS+ Fe (II)+ AA for treating landfill leachate. Central composite design (CCD) under response surface methodology (RSM) was used to design the experiment and predict the optimum operating conditions. The effects of independent parameters Le Persulfate dose, Fe (II) Dose, Hydroxylamine dose, Ascorbic acid dose, pH level and Reaction time were investigated with COD effluent concentration and COD removal efficiency as responses. From PS+ Fe (II)+ HA ANOVA analysis, COD effluent concentration is sensitive to PS dose, Fe (II) dose, Reaction time and the interaction between pH level and Fe (II) dose is significant. In COD removal analysis, effect of PS dose, Fe (II) dose, Hydroxylamine dose and Reaction time is significant. The interaction between pH level with reaction time and Fe (II) with pH is significant for COD removal under PS+ Fe (II)+HA treatment. The optimum treatment condition for PS+ Fe (II)+ HA treatment is at 0.58 µM, 38 μΜ, 15 μΜ, 2.13, 31 minutes for PS dose, Fe (II) dose, Hydroxylamine dose, pH level and reaction time, respectively. The optimum condition is predicted to achieve COD effluent of 642 mg/L with COD Removal of 56%. The experimental value under optimum condition obtained for COD effluent concentration and COD removal was 967 mg/L and 70%, respectively. The parameters that are significant under PS+ Fe (II)+ AA for COD concentration of effluent and COD Removal are Fe (II) dose and reaction time. For PS+ Fe (II)+AA treatment, the optimum condition is at PS dose of 0.34 µM, 28 µM of Fe (II), 35 µM of AA in fixed pH of 3.0 for 10 minutes with predicted COD effluent concentration of 22 mg/L and COD removal of 99%. The experimental value is found to be 568 mg/L for COD effluent concentration and COD removal of 82%. The study finds that Fe (II) activated PS enhanced with Hydroxylamine or Ascorbic acid can be used to remove COD from landfill leachate as AOP treatment and it provides an understanding on the effect of the working parameter to determine the optimum condition.

Includes bibliographical references