A single stage nitritation-anammox pilot scale SBR was implemented to treat reject water from sludge dewatering. The SBR was operated with a new strategy, a combination of interval feeding with interval aeration using the oxidation-reduction potential (ORP) as the main process indicator parameter. The strategy allowed for optimized treatment of high nitrogen loaded reject water providing stable operation and achieving a nitrogen removal efficiency of more than 90% at a volumetric nitrogen load of 400 g N m(-3) d(-1). COD removal was also observed with an efficiency of around 70%. The concept of interval feeding monitored by the ORP also allowed for adjustments to changing environmental conditions (i.e., decrease in temperature) by adjusting the number of intervals per cycle and the number of cycles per day. The distinct swing in the ORP signal which showed the largest amplitudes and most distinct pattern of all monitored parameters made the ORP the most favorable control parameter for nitritation-anammox in this type of SBR. (C) 2011 Elsevier B.V. All rights reserved.