Conditioning of aluminium - based water treatment sludge with 1 Fenton ’ s

13 Alternative conditioning of aluminium-based drinking water treatment sludge 14 using Fenton reagent (Fe 2+ /H2O2) was examined in this study. Focuses were placed on 15 effectiveness and factors to affect such novel application of Fenton process. 16 Experiments have demonstrated that considerable improvement of alum sludge 17 dewaterability evaluated by capillary suction time (CST) can be obtained at the 18 relative low concentrations of Fenton reagent. A Box-Behnken experimental design 19 based on the response surface methodology was applied to evaluate the optimum of 20 the influencing variables, i.e. iron concentration, hydrogen peroxide concentration and 21 pH. The optimal values for Fe 2+ , H2O2, and pH are 21 mg g -1 DS -1 (dry solids), 105 mg 22 g -1 DS -1 and 6, respectively, at which the CST reduction efficiency of 48±3 % can be 23