Deterioration of granular activated carbon collected from post-ozonation upflow fluidized bed contactor—influence of particle diameter

Abstract

An examination was undertaken of the properties of granular activated carbon (GAC) collected from a post-ozonation upflow fluidized GAC contactor at a full-scale advanced water purification facility operated by the Hanshin Water Supply Authority (HWSA), Japan. Activated carbon (AC) was collected from the upper, middle, and lower layer of the contactor and fractionated by a series of sieves. The amount of manganese, iron and calcium accumulated on each fraction was estimated by hydrochloric acid extraction test. The amount of iodine adsorption (I N ) was also measured. The amounts of metal accumulated were 1.2–89 (mg Mn g−1), 1.4–4.3 (mg Fe g−1), and 6.6–32 (mg Ca g−1). The amount was affected not only by the layer from which the carbon was collected but also by the average particle diameter of each fraction. I N was in the range of 119–527 (mg g−1) and decreased from the lower through the middle to the upper layer. Judging from I N , the AC collected from the upper layer, the furthest downstream, was subject to particular deterioration. A number of potential factors affecting the deterioration of GAC were suggested.