A fixedfilm system composed of an anaerobic biofilter and an intermittently aerated biofilter (IABF) was developed for enhanced biological phosphorus removal (EBPR) in the treatment of domestic wastewater. We investigated the influence of the operating regime on the performance of EBPR in IABF. Compared to the sequencing batch regime, net phosphorusuptake capacity in IABF was improved under the aerobic continuous feeding (ACF) regime. An innovative method that can be used instead of traditional backwashing was applied to IABF for removal of phosphorus from the reactor under the ACF regime. Using this method, a stable performance of EBPR was achieved during longterm operation, with a low frequency of backwashing in IABF. Distribution and variation of organic and phosphorus in IABF may imply spatial distribution of microorganisms in the column of the reactor under the ACF regime. 