Sludge Disintegration using Fenton Treatment

Activated sludge treatment has been widely applied to treat wastewater due to its
advantages, including low running cost and high degradation efficiency. However,
the cost of waste activated sludge treatment is notably high, representing more than
half of the total operating costs of the wastewater treatment plant facilities. Thus, the
study is conducted to investigate the optimum operating conditions on amount of
H2O2/kg TS, H2O2/Fe2+ molar ratio and reaction time for Fenton treatment of settled
activated sludge. The experiments were conducted by varying the amount of
Fenton’s reagent, fixed at pH 3, allowing for selected reaction time following the
Central Composite Design combinations by Design Expert software. For
performance evaluation, mixed liquor volatile soluble solids (MLVSS), soluble
chemical oxygen demand (sCOD), capillary suction time (CST) and extracellular
polymeric substances (EPS) were measured. The optimum conditions were found to
be 25 g H2O2/kg TS, H2O2/Fe2+ molar ratio 14 and reaction time 1.5 h with MLVSS
removal 23% to 28%, sCOD 5000 mg/L to 6200 mg/L, CST 129 s to 170 s and EPS
80 mg/L to 115 mg/L. In sum, within the study range of chemical dosages in this
research, the mechanism of sludge disintegration in Fenton treatment reduced the
sludge quantities, however, impaired its dewaterability.