Couplage de la filtration granulaire aux résines échangeuses d'ions pour le traitement des eaux de surface des petites communautés

Surface water treatment can be very difficult, especially for small systems. Because of the great amount of dissolve organic matter, when chlorine is used for disinfection, there is a risk to produce disinfection by-products that can be harmful for the health. Two of the most commons disinfection by-products, trihalomethanes (THM) and halo-acetic acids (HAA), have been standardized by the environmental department in Quebec (MDDEFP). Since they are a lot of small communities (3000 people or less) in Canada that have inadequate treatment systems, it is important to find new process that are efficient, reliable and easy to operate at low cost. The study of granular filtration followed by ion-exchange resins was done in order to determine its applicability and performance for the treatment of raw surface water. Granular filtration was tested in warm and cold water conditions. Ten different configurations were tested to see the effects of velocity, media type and media size on the treated water quality. Three velocities were tested: 2 m/h, 5 m/h and 10 m/h. Also, media size was separated in two types: standard size meaning granular activated carbon with an effective size of 1,17 mm and sand with an effective size of 0,36 mm and, small size meaning granular activated carbon of 0,63 mm and sand of 0,2 mm. Two configurations of filters were also tested: dual-media (standard size GAC and sand) and triple-media filters (standard size GAC and sand with ilmenite (0,2 mm)). Finally, to verify the effect of media type, an anthracite filter with sand was compared to a GAC filter with sand.