The experimental filter PRB2 contains specially developed pellets that remove heavy metals (500 mg/L) from acid (pH 5) percolate (1 - 10 m3/day) that leaves the re-deposited mining waste with lead-arsenic sulfide/sulfate from the abandoned Baccu Locci mine.
Sardinia is the second-largest island in the Mediterranean Sea (after Sicily). The area of Sardinia is 24,090 square kilometres (9,301 sq mi). The island is surrounded (clockwise from north) by the French island of Corsica, the Italian Peninsula, Tunisia and the Balearic Islands. Sardinia is a constitutional part of Italy, with a special statute of regional autonomy under the Italian Constitution. http://en.wikipedia.org/wiki/Sardinia