Cultivation of aerobic granular sludge for rubber wastewater treatment

► Aerobic granular sludge showed excellent settling ability and sludge volume index. ► A COD removal rate of 96.5% was observed at an OLR of 3.7kg CODm−3d−1. ► Ammonia and total nitrogen removal efficiencies were 94.7% and 89.4%, respectively. Aerobic granular sludge (AGS) was successfully cultivated at 27±1°C and pH 7.0±1 during the treatment of rubber wastewater using a sequential batch reactor system mode with complete cycle time of 3h. Results showed aerobic granular sludge had an excellent settling ability and exhibited exceptional performance in the organics and nutrients removal from rubber wastewater. Regular, dense and fast settling granule (average diameter, 1.5mm; settling velocity, 33mh−1; and sludge volume index, 22.3mLg−1) were developed in a single reactor. In addition, 96.5% COD removal efficiency was observed in the system at the end of the granulation period, while its ammonia and total nitrogen removal efficiencies were up to 94.7% and 89.4%, respectively. The study demonstrated the capabilities of AGS development in a single, high and slender column type-bioreactor for the treatment of rubber wastewater.