Formation of Aerobic Granules Using Industrial Wastewater

Aerobic granulation is a new and promising technology to intensify land use in wastewater treatment processes, up to 20% of the conventional activated sludge systems. So far, the aerobic granulation has been mainly studied using synthetic wastewaters. Although, this system is seen as an economical alternative, it has not investigated in sufficient details for treatment of industrial wastewaters. The objective of this study was to evaluate performance of the aerobic granulation for post treatment of the effluents of baker's yeast wastewater after anaerobic treatment in upflow anaerobic sludge bed (UASB) reactor. The COD removal in the UASB reactor was ranged between 70-75% at loading rate of 26 kgCOD/m'.d. The effluent of the UASB reactor was used for feeding of a sequencing batch bubble column reactor (SBBC) inoculated with activated sludge from a municipal waste water treatment plant. After one month, stable granules were developed in the system. After 3 months of operation, the sludge volume index (SVI) after 3 minutes of settling was 52 ml/g TSS with excellent settling ability and an average diameter of 1.2 mm. The COD removal of 67% COD was achieved only in SBBC reactor at a maximum loading rate of 2.3 kgCOD/mod. For the combined UASB and aerobic granular sludge system, the COD removal was observed to be more than 90%.