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Arsenic in drinking water causes severe health effects and it is widely diffused in groundwater around the world.\ud This paper presents the results of a survey about the main arsenic removal technologies employed in Italy and\ud the main features in the management of real treatment plants. 19 drinking water treatment plans were involved\ud in this study. The specific aspects analysed in this survey were: type of technologies applied in the drinking water\ud treatment plants (water characteristics, ionic form of As in raw water, etc.), technical aspects (chemical dosage,\ud treatment steps, hydraulic load, retention time, etc.), operational aspects (backwashing, media regeneration,\ud management of residues, etc.) and costs of these technologies. In Italy, the main technologies employed are\ud chemical precipitation (10 plants) and adsorption with granular ferric hydroxide (GFH) (six plants). Two of\ud these plants employ both chemical precipitation and GFH. Moreover, there are some applications of adsorption\ud on titanium dioxide (two plants), reverse osmosis (two plants) and ionic exchange (two plants

Arsenic is a widespread contaminant in the environment around the world. The most abundant species of arsenic in groundwater are arsenite [As(III)] and arsenate [As(V)]. Several arsenic removal processes can reach good removal yields only if arsenic is present as As(V). For this reason it is often necessary to proceed with a preliminary oxidation of As(III) to As(V) prior to the removal technology. Several studies have focused on arsenic oxidation with conventional reagents and advanced oxidation processes. In the present study the arsenic oxidation was evaluated using hydrogen peroxide, UV radiation and their combination in distilled and in real groundwater samples. Hydrogen peroxide and UV radiation alone are not effective at the arsenic oxidation. Good arsenic oxidation yields can be reached in presence of hydrogen peroxide combined with a high UV radiation dose (2,000 mJ/cm(2)). The quantum efficiencies for As(III) oxidation were calculated for both the UV photolysis and the UV/H(2)O(2) processes.