Culligan arsenic removal system ensures utility’s compliance with new regulations
Culligan and Zilio S.p.A have provided Acqualatina S.p.A. with Italy’s first large scale water treatment system designed to remove arsenic and other contaminants from municipal water supplies. The Culligan system, which is the largest installed in Italy for the potabilization of water and one of the largest municipal systems in Europe designed for arsenic removal, was inaugurated on Jan. 31, 2013 in Aprilia, a town in the province of Latina in the Lazio region of Italy. It will enable residents to draw potable water from municipal waterworks in compliance with new Italian regulations that took effect at the beginning of January.
The inauguration of the facility follows the expiration of exemptions for certain contaminants in drinking water. Among the main contaminants for which exemptions had previously been granted were arsenic and vanadium. These elements frequently occur naturally in the region’s water as a result of particular geological formations that release the contaminant ions directly into the water as it flows through deep aquifers.
Following the issuance of a public tender, Acqualatina awarded Culligan a contract to design and provide a municipal water treatment system that would reduce these contaminants in compliance with the new and more stringent regulations. The new maximum permissible value for Arsenic is 10 micrograms per liter, and 50 micrograms per liter for vanadium.
"With this system, which I remember is the largest in Italy and one of the largest in Europe, it has been possible to be within the limits of arsenic concentration in the water, as established by law regulations since Dec. 28, 2012," said Giuseppe Addessi, president of Acqualatina S.p.A.
For the Acqualatina project, Culligan partnered with arsenic treatment specialists Zilio S.p.A and the process of adsorption by means of an arsenic and vanadium removal mineral was selected. The mineral employed has a particular affinity with these elements, causing them to bind to the porous surface of the minerals.
The water to be treated is drawn from six water wells with an average arsenic concentration of 12 µg/L, with a maximum flow rate of 600 liters per second. Once treated, the water is conveyed to a storage and recovery tank.
The Culligan system consists of four filtration lines assembled in a clover configuration. Butterfly valves with a pneumatic actuator are installed in a 20-ft container, which also houses the local control unit.
The installation includes a colorimetric analyzer for arsenic, designed to monitor, through a customizable program, the concentration of arsenic in the raw water, in the treated water and at the various phases of the process. To maximize the efficiency of the minerals, the system also incorporates an automatic chemical pre-treatment.