The removal efficiency of sequencing batch reactor (SBR) system with synthetic industrial estate wastewater (SIEWW) containing Ni2+ or Pb2+ was increased with the increase of mixed liquor suspended solids (MLSS). But, the sludge volume index (SVI) of the system was increased up to higher than 100 mL/g under MLSS of up to 4000 mg/L Also, the effluent NO3- was decreased with the increase of MLSS. The heavy metals (Ni2+ or Pb2+), BOD5. COD and TKN removal efficiencies of SBR system with SIEWW containing 5 mg/L heavy metal (Ni2+ or Pb2+) under MLSS of 3000 mg/L were 83-85%, 96-97%, 95-96% and 83-94%, respectively. The increase of heavy metal (Ni2+ or Pb2+) concentrations of SIEWW from 5 to 50 mg/L were not significantly effected to both COD and BOD5 removal efficiencies (they were reduced by only 4-5%), but they were strongly effected to both TKN and heavy metals removal efficiencies (they were reduced by 15 and 20-30%, respectively). Both Ni2+ and Pb2+ could repress the growth of both nitrification and denitrification bacteria. And Ni2+ was more effective than Pb2+ to reduce the heavy metals removal efficiency. The SBR system could be applied to treat the industrial estate wastewater (IEWW) containing both Pb2+ and Ni2+ even the heavy metals concentrations was up to 5 mg/L, but the removal efficiency was quite low and excess bio-sludge did not produce. However, the system efficiency could be increased with the increase of BOD5 concentration of the wastewater. The Pb2+ Ni2+ COD, BOD5 and TKN removal efficiencies of the system with IEWW containing 500 mg/L BOD5, 5 mg/L Ni2+ and 5 mg/L Pb2+ under HRT of 3 days were 85.68 +/- 0.31%, 87.03 +/- 0.21%, 86.0 +/- 05%, 94.04 +/- 0.4% and 90.5 +/- 0.9%, respectively. And the effluent SRT, SS and SVI of the system were 44.7 +/- 0.6 days, 150 +/- 6 mg/L and 100 mL/g, respectively. (C) 2008 Elsevier B.V. All rights reserved.