TECHNICAL INFORMATION

Multi-media filtration process, an exclusive feature consisting of three minerals of different grain sizes arranged in layers so that the top layer (anthracite media) consisting of larger particle size followed by layers with diminishing grain size (garnet) and fine gravel. See diagram below. Raw water passes through the filter bed in a down-flow direction and distributes turbidity gradually throughout the filtering mass. Larger suspended particles are held by the first layer while the smaller particles are held by the finer and progressively more compact underlying strata.

Multi-media filtration process works on the physical and chemical phenomenon of spontaneous flocculation that occurs naturally due to the decreasing dimension of grain size. Spontaneous flocculation is a result from the progressive increase in velocity of water going through the mass to the point where such velocity succeeds in breaking the electrochemical equilibrium of the colloids. Such phenomenon cannot occur in filter beds consisting of one single filter media because the velocity of the water does not undergo the necessary progressive acceleration. Multi-media filtration process also makes backwash cycle more efficient because of the shallow dept of each filtering layer and gradual enlarging of the interstitial volume from the bottom to the top, thus allowing better removal of turbidity accumulated in the filtering bed during the filtration cycle.