Survey on full-scale drinking water treatment plants for arsenic removal in Italy

Abstract

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