Development of Aerobic Granular Sludge for Chemical Industries Wastewater Treatment

Abstract

Background: The world’s chemical industries are confronted with formidable environmental regulatory challenges in treating their wastewaters. Aerobic granulation is increasingly drawing interest of researchers engaging work in the area of biological wastewater treatment. Objectives: The objective is to develop a new cost-effective technique for treatment of chemical industry effluents. The possibility and effectiveness of this new enhanced biological treatment system were determined through mean diameter, relative hydrophobicity, sphericity, and sludge volume index (SVI5) of aerobic microbial aggregates. Scanning electron microscopy (SEM) analysis was also used to characterize the granules. Methods: The granules were cultivated in a single sequencing batch reactor (SBR) system fed with synthetic ethylene glycol (MEG) wastewater. The characteristics of the aerobic granular sludge were monitored during the study period. Results: Aerobic granules with dense and strong microbial structure as well as excellent settling ability were cultivated. Developed granules had an average size of 8.21 ± 2 mm. The process of granulation resulted in an increased biomass concentration from about 2500 to 4750 mg/L. The microbial granular sludge was able to remove 97% of the influent COD at organic loading rate (OLR) of 2.0 kg COD/m3.day, at the end of the study. Conclusions: The findings of the present study revealed that aerobic granular sludge could be successfully developed in a SBR and is capable in treating the simulated chemical industries wastewater.