This study was conducted to evaluate domestic sewage treatment using a special sequencing batch biofilm reactor (SBBR). To optimize the operation of traditional SBBRs and reduce the aeration phase, a newly developed intelligent controlling system (ICS) was adopted to control the SBBR. Stable performance was achieved in the SBBR at a hydraulic retention time (HRT) of 7 h, at which point the removal efficiencies of NH3-N, TP and COD reached 99%, 100% and 96%, respectively. When compared with conventional SBBRs, the SBBR controlled by the ICS reduced the HRT and total aeration time by 56% and 50%, respectively, and achieved better performance at removing the COD. In addition, the optimal carbon nitrogen (COD/N) ratio for the simultaneous removal of nitrogen and COD in the SBBR was found to be 12.5, and no accumulation of NO3--N or NO2--N was detected at this ratio, indicating that efficient simultaneous nitrification and denitrification (SND) was occurring in the reactor. The SND efficiency reached 98%. (C) 2011 Elsevier B.V. All rights reserved.