Roles of an easily biodegradable co-substrate in enhancing tetracycline treatment in an intimately coupled photocatalytic-biological reactor. (1st June 2018)

• Record Type: Journal Article
• Authors: Xiong, Houfeng; Dong, Shuangshi; Zhang, Jun; Zhou, Dandan; Rittmann, Bruce E.
• Is Part Of: Water research. Volume 136(2018)
• Page Start: 75
• Page End: 83
• Publication Date: 2018-06-01
• Subjects: Co-substrate -- Photocatalysis -- Biodegradation -- Biotransformation -- Mineralization -- Microbial community; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2018.02.061
• Languages: English
• ISSNs: 0043-1354

Abstract

Abstract: Intimately coupled photocatalysis and biodegradation (ICPB) was realized in a macroporous carrier in which a photocatalyst was present on the outer surface, while a biofilm accumulated inside the carrier. In ICPB, photocatalysis products are rapidly biodegraded by a protected biofilm, leading to mineralization of the refractory organics, such as antibiotics. However, mineralization in ICPB could be compromised if the photocatalysis products remain refractory or are inhibitory. To address this, we attempted to increase metabolic activity by providing a readily biodegradable co-substrate (acetate) that could act as a source of energy and electrons to improve biotransformation and mineralization of the refractory antibiotic tetracycline (TCH). When we added acetate during ICPB of TCH, TCH removal increased by ∼5%, mineralization increased by ∼20%, and almost all photocatalysis products disappeared. Acetate addition also led to an increase in active biomass, an increase in the biomass's respiratory activity, and evolution of the microbial community to having more members able to biodegrade photocatalysis and biotransformation intermediates. Thus, providing an easily biodegradable co-substrate was an effective means for enhancing TCH removal and mineralization with the ICPB technology. Graphical abstract: Highlights: Intimately coupled photocatalysis and biodegradation (ICPB) is a means to biodegrade and mineralize refractory organics. Biodegradation and mineralization of the antibiotic tetracycline (TCH) was accelerated by ICPB. Adding a readily biodegradable substrate enhanced the acceleration effect of ICPB. Acetate addition enriched the biofilm in bacterial genera able to utilize TCH photocatalysis products.