The recovery performance of the anaerobic ammonium oxidation (ANAMMOX) upflow anaerobic sludge blanket reactors (R-1, R-2) that were previously subjected to copper (II) and oxytetracycline (OTC) inhibitors with respective levels of 0.5-5 and 6-50 mg L-1 and then operated in the absence of such inhibitors was investigated in this study. High nitrogen removal rates of 30.1 and 30.9 kg m(-3) d(-1), were accomplished respectively for R-1 and R-2 after reactivation. The performance recovery was well indicated by change in pH, stoichiometric ratio, specific ANAMMOX activity, and morphological and physical properties of ANAMMOX granules. The modified Stover-Kincannon model properly simulated the regain performance, and theoretical removal rates of 151.5 and 212.8 kg-N m(-3) d(-1) were predicted for R-1 and R-2, respectively. The ANAMMOX activity and performance initially stressed by copper (II) and OTC for a long time (nearly 200 days) were restorable and the recovery process lasted for a relatively short time (56 and 51 days for R-1 and R-2, respectively). (C) 2013 Elsevier B.V. All rights reserved.