Arsenic removal with chemical precipitation in drinking water treatment plants in Italy

摘要

In Italy, arsenic is diffused in the groundwater in several areas with concentration also higher than 300 μg/L. A research performed in the University of Brescia investigated the main operations of upgrading employed by several drinking water treatment plants in Italy. The aim of this work was to elaborate an handbook about the arsenic diffusion in drinking water in Italy, the arsenic removal technologies applied in this country and the technical and operational aspects tied to these technologies. Sixteen drinking water treatment plants were analyzed in detail. Ten of them applied chemical precipitation process, one of the most common technology for arsenic removal in Italy. Treatment plants with arsenic removal by precipitation are generally composed of:aeration; biological filtration and/or pre-oxidation with chemicals; addition of chemicals for arsenic precipitation; sand filtration; possible adsorption with Granular Ferric Hydroxide (GFH) for arsenic removal and final disinfection. This paper reports information about the technical and operational aspects with focus on the process scheme, chemical dosage, residues management and costs.