Some of the more common metals or other substances removed via precipitation include: 1) Aluminum
2) Arsenic
3) Barium
4) Cadmium
5) Calcium
6) Trivalent chromium
7) Hexavelent chromium
8) Copper
9) Iron
10) Lead
11) Magnesium
12) Manganese
13) Mercury
14) Nickel
15) Selenium
16) Zinc