Triclocarban-contaminated wastewater treatment by innovative hybrid moving entrapped bead activated sludge reactor (HyMER): Continuous performance and computational dynamic simulation analysis

Abstract

Triclocarban (TCC) has been used in consumer products and is a widespread contaminant in municipal wastewater treatment systems that ultimately accumulates in natural receiving water and soil. This work aims to apply an innovative hybrid moving entrapped bead activated sludge reactor (named “HyMER”) that integrates entrapped TCC-degrading microbes and freely suspended activated sludge to treat TCC-contaminated wastewater. A previously isolated TCC-degrading bacterium (Pseudomonas fluorescens strain MC46, called MC46) and barium alginate entrapment were applied. The synthetic TCC-contaminated wastewater treatment (with TCC concentration of 10 mg/L) was performed using 20-cycle fed-batch reactor operation with feeding times of 12 and 24 h and cycle times of 13 and 25 h. The results indicated that the HyMER effectively reduced chemical oxygen demand by up to 80 and 95 % and TCC by up to 53 and 83 %, respectively, with feeding times of 12 and 24 h. Three TCC degradation intermediate products were found—3,4-dichloroaniline, 4-chloroaniline, and aniline. Scanning electron microscopic analysis revealed shorter cells and bacterial appendage development as cell adaptations against TCC and its intermediates. The live/dead assay indicated high survival of entrapped MC46 in toxic conditions, with up to 84 % viable cells. Based on computational fluid dynamic analysis, no entrapped cell agglomeration showed in the reactor, indicating the potential application of HyMER for real wastewater treatment. These results exhibit the feasibility of HyMER and its applicability for future toxic wastewater treatment.