Comparison between aerobic and anaerobic membrane bioreactors for trace organic contaminant removal in wastewater treatment

Abstract

This study compared the removal of fifteen trace organic contaminants (TrOCs) by aerobic and anaerobic membrane bioreactors, denoted as AeMBR and AnMBR, respectively. Results show that the removal of TrOCs by either AeMBR or AnMBR was determined largely by their hydrophobicity. Almost all hydrophobic TrOCs were effectively removed ( > 60%) while the removal of hydrophilic compounds varied (3.6%–98.7%). AeMBR was more effective than AnMBR for the removal of all TrOCs investigated with a few exceptions. Compared to AeMBR, the removal of compounds containing nitrogen in their molecular structures (e.g. amitriptyline, carbamazepine, and atrazine) was higher by AnMBR. Of all TrOCs investigated, considerable accumulation in biosolids only occurred to amitriptyline, 4-tert-octyphenol and triclosan, particularly during AnMBR treatment. Nevertheless, biodegradation and/or biotransformation was the main mechanism for TrOC removal by both AeMBR and AnMBR. Moreover, removal of bulk organic matter indicated by total organic carbon and nitrogen was comparable for these two systems. • Hydrophobic TrOCs could be effectively removed ( > 60%) by both AeMBR and AnMBR. • Removal of hydrophilic TrOCs by the two systems varied notably from 3.6% to 98.7% • AeMBR was more effective for the removal of most TrOCs than AnMBR. • AnMBR had higher removal of TrOCs with nitrogen in their molecular structures. • AeMBR and AnMBR were comparable for removal of organic matter (i.e. TOC and TN).