In this study, petrochemical wastewater from the port of Antwerp was used for the development of aerobic granular sludge. Two different reactor setups were used, (1) a completely aerated sequencing batch reactor (SBRae) with a feast/famine regime and (2) a sequencing batch reactor operated with an anaerobic feast/aerobic famine strategy (SBRan). The seed sludge showed poor settling characteristics with a sludge volume index (SVI) of 285 mL.g MLSS-1 and a median particle size by volume of 86.0 mu m +/- 1.9 mu m. In both reactors, granulation was reached after 30 days with a SVI of 71 mL.g MLSS-1 and median granule size of 264.7 mu m in SBRan and a SVI of 56 mL.g MLSS-1 and median granule size of 307.4 mu m in SBRae. The chemical oxygen demand (COD) and dissolved organic carbon (DOC) removal was similar in both reactors and above 95%. The anaerobic DOC uptake increased from 0.13% to 43.2% in 60 days in SBRan. (C) 2017 Elsevier Ltd. All rights reserved.