Patent EP-2511239-A1 (EP)
Inventor: GIRAUD ISABELLE
IPC: C02F1/28
Filed: 2012-04-05
Abstract: Process for treating water to be treated involves: a step for clarifying the water to be treated producing a clarified water; a step for placing a part of the clarified water in contact with a powdered adsorbent reagent (21) producing a mixture of clarified water and powdered adsorbent reagent; a step for mixing the mixture with the water to be treated; and a step for discharging the remainder of the clarified water. The step for clarifying involves: coagulating the water; flocculating coagulated water; and decanting flocculated water producing clarified water and sludges. Process for treating water to be treated involves: a step for clarifying the water to be treated producing a clarified water; a step for placing a part of the clarified water in contact with a powdered adsorbent reagent (21) producing a mixture of clarified water and powdered adsorbent reagent; a step for mixing the mixture with the water to be treated; and a step for discharging the remainder of the clarified water. The step for clarifying involves: a step for coagulating the water to be treated producing coagulated water; a step for flocculating the coagulated water producing flocculated water; a step for decanting the flocculated water producing the clarified water and sludges. About 25-75 (preferably 45-55)% of the clarified water coming from the clarification step or the decantation step is put into contact with the powdered adsorbent reagent. The dissolved organic carbon concentration of the water to be treated is below 10 mg/l. The powdered adsorbent reagent is powdered activated carbon. The method involves a step for thickening the sludges, and a step for introducing the thickened sludges thus obtained into the mixture. Independent claims are included for the following: (1) a water treatment plant for treating water to be treated to implement the process comprising device for clarifying the water to be treated (111) and device for extracting clarified water at exit from the device for clarifying, where it comprises device (19) for re-circulating a part of the clarified water into a stirred pre-contact zone (20), device for injecting a powdered adsorbent reagent into the pre-contact zone, and a mixing zone (11), where the mixing zone comprises a first inlet (110) connected to the outlet of the pre-contact zone, a second inlet for the water to be treated and an outlet leading into the device for clarifying. The device for clarifying comprise a coagulation zone (13), a flocculation zone (15), and a decantation zone (17) mounted in series, and device (171) for extracting the clarified water at exit from the decantation zone, where the outlet of the mixing zone leads into the coagulation zone; and (2) a process for renovating an existing plant for treating water to be treated comprising device for clarifying the water to be treated, involving a step consisting in linking the device for re-circulating a part of the clarified water to the outlet of the clarifying device; a step consisting in connecting the device for re-circulating to a pre-contact zone comprising device for injecting a powdered adsorbent reagent; a step consisting in installing a mixing zone, of which a first inlet is connected to the outlet of the pre-contact zone, a second inlet is connected to an intake of the water to be treated and the outlet is connected to the device for clarifying.