The present study reports kinetic characteristics of Anammox (anaerobic ammonium oxidation) EGSB (Expanded Granular Sludge Bed) reactor after feeding with strong ammonium-containing synthetic wastewater. The microbial communities were analysed based on their 16S rRNA gene sequences. The results showed that the volumetric nitrogen loading rate (NLR) and volumetric nitrogen removal rate (NRR) reached up to 22.87 kg N/(m(3) d) and 18.65 kg N/(m(3) d), respectively, when the influent nitrogen concentrations were 1429.1 mg N/L Monod and Haldane models both proved to be suitable in characterizing the kinetic behavior of the reactor. Based on Haldane model, the relationships among the ammonium, nitrite, nitrogen conversion rates and substrate concentrations were established with corresponding correlation coefficients of 0.992, 0.993 and 0.993, respectively. The maximum ammonium, nitrite and nitrogen conversion rates (q(max)) by the granular sludge were 381.2, 304.7 and 731.7 mg N/(gVSS d), half saturation constants (K(s)) were 36.75, 0.657 and 29.26 mg NIL and inhibition constants (K(i)) were 887.1, 13,942.1 and 1779.6 mg N/L, respectively. Anammox-EGSB reactor was found tolerant to substrate and capable of treating strong ammonium-containing wastewater. The dominant microbial population of the granular sludge in the reactor was Candidatus Kuenenia stuttgartiensis. (C) 2010 Elsevier B.V. All rights reserved.