Flow pattern analysis of a full-scale expanded granular sludge bed-type reactor under different organic loading rates

► We model the flow pattern of a lab-scale and a full-scale EGSB-type reactor. ► We investigate the hydraulic characteristics under different organic loading rates. ► The model structure agrees well with the physical structure of full-scale reactor. ► The sludge bed of the EGSB-type reactor performed as a suspended bed. ► Flow pattern, biomass, and gas hold-up effect contribute to the large dead space.