الفهرس 
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Abstract
This study contributes to the exploration and development of the use of the Fenton and the
photo-Fenton’s reagents for alum sludge conditioning and oily-wastewater treatment.
In Ireland, a double fold increase of drinking water treatment sludge is predicted by the end of
the next decade. Currently, organic polymers are adopted in alum sludge conditioning. However,
there are increasing concerns regarding the use of these organic polymers because of the unknown
and long-term effects of the potential release of excess polymer to the surrounding environment
when the sludge is landfilled. Therefore, as an initiative action, alternative conditioning of
aluminium-based drinking water treatment sludge using Fenton reagent (Fe2+/H202) was examined.
Focuses were placed on effectiveness and factors to affect such a novel application of Fenton
process. Experiments have demonstrated that considerable improvement of alum sludge
dewaterability evaluated by capillary suction time (CST) can be obtained at the relativelly low
concentrations of Fenton reagent. A Box-Behnken experimental design based on the response
surface methodology (RSM) was applied to evaluate the optimum of the influencing variables, i.e.,
iron concentration, hydrogen peroxide concentration and pH. The optimal values for Fe2+, H202, and
pH were found to be 21 mg g’ OS-’ (dry solids), 105 mg g’ OS-’ and 6, respectively, at which the
eST reduction efficiency of 48±3 % can be achieved, this agreed with the values predicted by an
established polynomial model in this study.
Experiments have been conducted to test the effectiveness of Fenton’s reagent (Fe2+ and H202)
containing the ferrous salts of chloride, sulphate or oxalate, Fenton-like reagent (Fe3+/H202)
containing ferric salts of chloride and sulphate and the traditional coagulation method using FeCh
for alum sludge conditioning at a constant hydrogen peroxide and iron salt concentrations of 125
and 20 mg g-OS-’, respectively. The effectiveness of these methods on the dewaterability of the
alum sludge demonstrated that the maximum % of Specific Resistance of Filtration (SRF) and CST
reached 74% and 47% and (64% and 38%), for Fenton and Fenton-like reagents, respectively. The
ferrous chloride salt is the recommended salt which showed the maximum dewaterability.
Moreover, the optimum pH was 6 (without any adjustment). However, this value may differ
according to the iron salt used. Temperature had a positive effect on the sludge conditioning with
Fenton’s reagent