Aerobic granulation for methylene blue biodegradation in a sequencing batch reactor

Aerobic granules to treat wastewater containing methylene blue (MB) were successfully developed in a sequencing batch reactor (SBR) using activated sludge as inoculum. After cultivation for 87 days, stable aerobic granules were obtained with a clearly defined shape and a diameters ranging from 2 to 4 mm. After granulation, the removal efficiencies of MB and chemical oxygen demand (COD) reached 56% and 93%, respectively. Specific MB biodegradation rates followed the Haldane model and the associated kinetic parameters were as follows: Vmax = 184.15 mg L− 1 h− 1, Ks = 209.96 mg L− 1, and Ki = 21.23 mg L− 1. The aerobic granules proved to be a feasible and effective way to degrade MB-containing wastewater.

Research highlights
► Demonstrated that aerobic granules for MB biodegradation could be obtained in a SBR.
► Haldane equation was proposed to describe the biodegradation of MB.
► Suggested the potential application of aerobic granules in dye wastewater treatment.