초록 ▼

A biological contactor (8) comprises a granular bed including a layer (17) based on activated carbon the material of which satisfies the following conditions: density between 0.18 and 0.32 g/cm3, carbon tetrachloride adsorbing power between 60% and 120% by weight, carbon tetrachloride retention less

A biological contactor (8) comprises a granular bed including a layer (17) based on activated carbon the material of which satisfies the following conditions: density between 0.18 and 0.32 g/cm3, carbon tetrachloride adsorbing power between 60% and 120% by weight, carbon tetrachloride retention less than 25% by weight of the carbon tetrachloride adsorbed mass, methylene blue: between 5 and 30 ml, particle size: between 0.5 and 1.5 mm effective size with a coefficient of uniformity less than 2. A washing cycle (21, 24) (air only; air plus water; water only) of the contactor is triggered (38) when a parameter (36, 37) representative of the population of algae in said layer reaches a predetermined set point threshold.

대표청구항 ▼

Method of controling a biological contactor (8, 40, 50) comprising a granular bed (17, 17′) containing a layer based on activated carbon adapted to provide purification in the production of drinking water, in which method: the material constituting the granular layer is chosen to meet the following

Method of controling a biological contactor (8, 40, 50) comprising a granular bed (17, 17′) containing a layer based on activated carbon adapted to provide purification in the production of drinking water, in which method: the material constituting the granular layer is chosen to meet the following conditions: density between 0.18 and 0.32 g/cm3, carbon tetrachloride adsorbing power between 60% and 120% by weight, carbon tetrachloride retention less than 25% by weight of the carbon tetrachloride adsorbed mass, methylene blue: between 5 and 30 ml, particle size: between 0.5 and 1.5 mm effective size with a coefficient of uniformity less than 2; the water to be treated is caused to flow downwards at a linear speed less than 45 m/h so as to achieve an empty bed contact time (water in contact with the bed) of at least five minutes; a parameter representative of the population of algae in the bed is monitored (36, 37); a washing cycle is triggered (38) when this parameter reaches a predetermined set point threshold, which cycle comprises the following steps after interruption of the supply of water to be treated: lowering the water level to at most the top of the granular bed, injecting air in a counterflow arrangement at an apparent speed of less than 80 Nm3/h.m2 at least until bubbles appear at the surface, injecting additional water in a counterflow arrangement with an apparent speed of 15 through 50 m/h until the water surface rises to an overflow level in the contactor, injection of air being continued for at least 30 seconds but interrupted before the water level reaches the overflow level, rinsing with water in overflow mode for 5 through 20 minutes with a water speed between 8 and 50 m/h; halting counterflow injection of water and the contactor is again supplied with water to be treated.