Patent ID: 7029578
Filing Date: 2006-04-18
Classification: C02F

Abstract:
1. A water treatment system, said system including a filter bed comprising four layers of inert particulate material such that, from the top layer (first layer) to the bottom layer (fourth layer), the coarseness of the particles decreases while the density of the particulate material increases, the layers comprising in succession: a first, top layer of particulate material comprising particles with a density in the range of 1.25 to 1.55 g/cc and within the size range of 1.6 to 2.5 mm; a second layer of particulate material comprising particles with a density in the range of 2.35 to 2.95 g/cc and within the size range of 0.5 to 0.85 mm; a third layer of particulate material comprising particles with a density in the range of 3.5 to 4.3 g/cc and within the size range of 0.2 to 0.6 mm; and a fourth, bottom layer of particulate material comprising particles with a density in the range of 4.0 to 6.0 g/cc and within the size range of 0.2 to 0.5 mm.