Aerobic Granular Sludge: an Advanced Technology to Treat Oil Refinery and Dairy Wastewaters

Abstract

Aerobic granular sludge (AGS) is an emerging and an advance technology for intensive and high-rate biological nutrient removal from wastewater that may play as important role in industrial wastewater treatment strategy in Iraq. Lab scale sequential batch reactor (SBR) operated with selected operation cycle was used to cultivate granular sludge for each of dairy and oil refinery wastewaters. Successful granulation process in each reactor was achieved after 72 day of operation. The results of experimental work proved the flexibility of AGS technology to treat refinery and dairy wastewater and withstand fluctuated load. The COD and NH4 removal efficiencies for oil refinery wastewater were 86% and 92%, respectively, with sludge volume index (SVI) of 50 ml/g and granules size distribution of (0.3-3) mm. While COD and NH4 removal efficiencies for dairy wastewater were 80% and 82%, respectively, with SVI of 70 ml/g and the large percentage of its granules were ranged between 0.3 and 0.5 mm and the other smaller percentage were ranged between 0.75 and 2 mm. In addition microbiology observations showed high diverse in microorganisms communities which indicated the presence of stabilized sludge in both reactors.