PROCEDE DE TRAITEMENT D'EAU PAR FLOCATION-DECANTATION LESTEE COMPRENANT UNE MESURE EN CONTINU DU LEST ET INSTALLATION CORRESPONDANTE

• Main Authors: BEAUDET JEAN FRANCOIS, SAUVIGNET PHILIPPE, GUILLOT SONIA, URSEL VALERY
• Format: Patent
• Language: French
• Published: 08.02.2008
• Subjects: CHEMISTRY; MEASURING; MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUIDLEVEL; METALLURGY; METERING BY VOLUME; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; PHYSICS; SEPARATION; TESTING; TRANSPORTING; TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE

L'invention a pour objet un procédé de traitement d'eau par floculation/décantation comprenant des étapes d'injection et de recirculation d'un lest, caractérisé en ce qu'il comprend une étape de mesure en continu de la concentration dudit lest et une étape de comparaison de ladite mesure avec des valeurs de référence. A method for treating water in a ballasted flocculation system comprises directing water into a ballasted flocculation zone and adding ballast and a flocculation reagent to the water to form a water-floc mixture. The water-floc mixture is directed into a settling zone to form treated water and sludge containing ballast. The ballast is then directed to a recirculation line where the ballast is recirculated to the ballasted flocculation zone. The method further includes determining the ballast concentration and comparing the ballast concentration with a predetermined threshold value. The rate at which ballast is recirculated to the ballasted flocculation zone is adjusted based on the determined ballast concentration and the predetermined threshold value. A ballasted flocculation system for treating water comprises a ballasted flocculation zone, a water inlet for directing water into the ballasted flocculation zone, and a flocculation reagent inlet for directing flocculation reagent into the ballasted flocculation zone. The system includes a settling zone for separating treated water from sludge containing ballast and a recirculation line for recirculating ballast from the settling zone to the ballasted flocculation zone. A first ballast inlet is operatively connected to the recirculation line for directing ballast into the ballasted flocculation zone. Finally, the system includes a sensor for measuring a parameter of ballast in the system.