Aerobic sludge granulation process in a 4-h sequencing batch reactor for treating low strength wastewater

Abstract

The aim of this study is to determine design and process parameters for the development of aerobic granules using actual low-strength domestic wastewater by further investigate the efficiency of anaerobic-aerobic-anoxic (AN/O/AO) in a 2.5 L lab-scale column bioreactor, fed with influent from local sewerage treatment plant and seeding with fresh inoculums (seed sludge) from activated sludge tank. The operation of the bioreactor complies with the 4 h wastewater treatment cycle and it’s specifically designed to be operated for 24 h continuously. Intermittent aeration setting mode is applied to run the sequencing batch reactor (SBR) to accelerate the development of the granules and enhance removal performances. An excellent average removal of Total Suspended Solids (~90 %), Chemical Oxygen Demand (~90 %), Ammoniacal Nitrogen (~80% with successfully converted to nitrate) and Phosphate (~100 %) was achieved in this aerobic granular sludge system. Matured, dense and compact granules with average size (1.80 ± 0.03 mm) in diameters were also successfully developed with a good settling velocity (40 m h-1) and 30 minutes Sludge Volume Index 30 (60 mL g-1).