Biodegradation of o-nitrophenol by aerobic granules with glucose as co-substrate

Aerobic granules to treat wastewater containing o-nitrophenol were successfully developed in a sequencing batch reactor (SBR) using activated sludge as inoculum. Stable aerobic granules were obtained with a clearly defined shape and diameters ranging from 2 to 6 mm after 122 days of operation. The integrity coefficient (IC) and granules density was found to be 98% and 1,054 kg m�3
respectively. After development of aerobic granules, o-nitrophenols were successfully degraded to an efficiency of 78% at a concentration of 70 mg L�1. GC-MS study revealed that the biodegradation of o-nitrophenol occured via catechol via nitrobenzene pathway. Specific o-nitrophenol
biodegradation rates followed the Haldane model and the associated kinetic parameters were found as follows: Vmax ¼ 3.96 g o-nitrophenol g�1VSS�1d�1, Ks ¼ 198.12 mg L�1, and Ki ¼ 31.16 mg L�1. The aerobic granules proved to be a feasible and effective way to degrade o-nitrophenol containing
wastewater.