Device for filtration of surface water, comprises a platform above which a first and a second layer of first and second media are positioned, a water inlet in an upper part of the device, and a water outlet above the first layer

摘要

The device for filtration of surface water, comprises a platform (2) above which a first layer (5) of first media having average diameter and high density grains and a second layer (6) of second media having average diameter and low density grains are positioned, a water inlet in an upper part of the device placed above the second layer, and a water outlet above the first layer. Ratio of the grain diameters is 3-8 such that the second media exists a gap between the grains. The gap has a sufficient diameter to allow a gravitational flow of the first media grains through the second layer. The device for filtration of surface water, comprises a platform (2) above which a first layer (5) of first media having average diameter and high density grains and a second layer (6) of second media having average diameter and low density grains are positioned, a water inlet in an upper part of the device placed above the second layer, and a water outlet above the first layer. Ratio of the grain diameters is 3-8 such that the second media exists a gap between the grains. The gap has a sufficient diameter to allow a gravitational flow of the first media grains through the second layer. The second layer has a fluidization speed greater than or equal to two times of the fluidization speed of the first layer. A unit is arranged for injecting the fluid at a level of the platform with a speed close to that of the fluidization speed. An independent claim is included for a process for filtration of surface water.