| Description |
In the last decade, the focus of biological wastewater treatment has shifted to efficiency and sustainability driven technologies. Due to this, the wastewater community has been inclined towards exploring innovative techniques of treatment. Aerobic granular sludge technology (GAS) is an advancement towards conventional treatment techniques, which utilizes a specialized granulated form of biomass known as aerobic granules (AG). AG are microbial aggregates possessing excellent settling characteristics along with simultaneous nitrification, denitrification and enhanced biological phosphorus removal capability. Due to its multivariate features, this technology has attracted a lot of attention in terms of research. Yet, a complete understanding of the key differences in performance and microbial composition between conventional flocs and aerobic granules when operated under similar conditions is not fully known. This research focuses on performing comparative analysis between the conventional and granular systems in terms of reactor start-up, operation, microbial composition and relative gene expression. It was accomplished by initiating two sequencing batch reactors (SBR) to culture aerobic granules and conventional flocs. The granulation process was initiated within 30 days of the reactor operation and reached to a maximum diameter of ~5mm within 90 days of operation. The conventional reactor system was initiated with the objective of operating it as control. The average removal in GAS was 1.84± 0.29 kg COD m-3d-1, 0.063±0.029 kg PO43--P m-3d-1 and iv 0.093±0.015 kg NH4+-N m-3d-1. The average removal in CAS was 1.14±0.12 kg COD m-3d-1, 0.028±0.012 kg PO43--P m-3d-1 and 0.051±0.009 kg NH4+-N m-3d-1 throughout the reactor operation with a much smaller hydraulic retention time exhibited by the granular reactor. To compare the overall microbial population within both the systems, an initial complete genome analysis was conducted. Our in-depth metagenomic analysis was capable of modelling a metabolic pathway as followed by both systems. A gradual change in the physical and biological characteristics was studied on shifting influent characteristics from synthetic to real wastewater. This study has the capability to provide the much-needed information on the comparative biological mechanisms between both the reactor systems. The current study can provide a basis for future application of GAS in full-scale treatment. |
