Patent FR-2910822-A1 (FR)
Title: Treating water filled with colloidal impurities in dissolved or suspension form using a treatment installation, comprises supplying the water in a flocculation zone, and introducing the mixture of water and flocs in a settling zone
Inventor: SAUVIGNET PHILIPPE
IPC: B01D21/01
Filed: 2006-12-29
Abstract: The process for treating water filled with colloidal impurities in dissolved or suspension form using a treatment installation, comprises supplying the water in a flocculation zone (1), introducing the mixture of water and flocs in a settling zone (11), separating the treated water from the mixture of sludge and the ballast obtained from the settling of the flocs in an upper part of the settling zone, and extracting the mixture of sludge and the ballast in a lower part of the settling zone for transmitting the intermediate mixture towards an agitating zone using an endless screw. The process for treating water filled with colloidal impurities in dissolved or suspension form using a treatment installation, comprises supplying the water in a flocculation zone (1), introducing the mixture of water and flocs in a settling zone (11), separating the treated water from the mixture of sludge and the ballast obtained from the settling of the flocs in an upper part of the settling zone, extracting the mixture of sludge and the ballast in a lower part of the settling zone for transmitting the intermediate mixture towards an agitating zone using an endless screw, extracting the mixture of sludge and the ballast present in the agitating zone for carrying out a sludge/ballast separation by hydrocyclone, recycling the sludge underflow from hydrocyclone in the flocculation zone, extracting a part of the sludge obtained from the overflow of the hydrocyclone and recirculating the other part of the sludge in the agitating zone, storing the overflowed sludge in a cover (31), and measuring a level of the sludge and ballast present in the intermediate mixture. A ballast is constituted of an insoluble granular material heavier than the water and a reactive flocculant forming the flocs, where the material having adsorption and ion or molecule exchange properties is resin and activated carbon powder. A parameter representating a concentration of water filled with impurities is continuously measured before or during the water entering into the flocculation zone by continuously deducting a quantity of ballast for obtaining the treated water with a predetermined quality. A concentration of ballast of extracted mixture from the settling zone or the mixture present in the flocculation zone is continuously measured by continuously deducting the concentration of ballast in the installation from the extracted mixture concentration of the settling zone. The flocculation zone is refilled by ballast when the concentration of ballast present in the installation is lower than a predetermined threshold. A coagulating reagent is continuously injected in the water before its entry in the flocculation zone according to their predetermined amount, where the reagent adjusts a pH according the predetermined amount. The parameter representing the concentration of water filled with impurities is a concentration of water from matter in suspension (total MES), which is calculated using the parameters consisting of the concentration of water in suspension material and in organic material, the concentration of microorganisms and micropollutants in raw water, and predetermined amount of coagulating reagent. The treated water with predetermined quality is determined using a formula Y = aX(b)+c, where Y is ballast concentration, X is the concentration of the total MES, a is 0.5-1, b is 0.3-1 and c is 0-2. The amount of reactive flocculant distributed in the flocculation zone is continuously adjusted for obtaining the treated water with predetermined quality, where the distribution is carried out by hydraulic distribution device. An auxiliary liquid of 5-20 vol.% is injected in the hydrocyclone. A completely immersed flux guide structure and an axial turbulent flow of water to be treated are delimited within the flocculation zone by agitation. The flow coming out of the flux guide structure is converted into axial flow using a static flow distribution device. An independent claim is included for an installation for treating water filled with colloidal impurities in dissolved or suspension form.