Wastewater treatment performance and microbial community of anode electrodes of membrane and membrane-less MFCs under effect of sunlight

• Published in: Journal of water process engineering 2021-08, Vol.42, p.102159, Article 102159
• Main Authors: Nguyen, Dao Anh, Pham, Ngoc, Pham, Hoa Thi
• Format: Article
• Language: English
• Subjects: Anode electrodes; Membrane-less; Microbial community; Microbial fuel cells (MFCs); Wastewater treatment
• ISSN: 2214-7144; 2214-7144
• DOI: 10.1016/j.jwpe.2021.102159

This study investigated the anodic microbial community and treatment efficiency of two MFC systems, membrane MFC (M-MFC) and membrane-less MFCs (ML-MFC) operated in the open environment under effect of sunlight. Both MFCs were inoculated with anaerobic sludge, operated under continuous mode in the open environment effected by sunlight, treated synthetic wastewater with step-wise increasing of organic loading rates (ORLs) of 3.0; 3.5; 4.0; and 4.5 g COD/L·day. The COD removal and the power generation were continuously monitored. COD removal efficiency of M-MFC for each OLR was 34.7 ± 23.7%, 76.7 ± 6.7%, 71.9 ± 0.7%, and 67.9 ± 2.8%, respectively. For the ML-MFC, COD removal efficiency was 54.3 ± 13.5%, 73 ± 1.7%, 73.7 ± 1.6%, and 68.1 ± 4%, respectively. Power density of ML-MFC under all ORLs was much higher than that of the M-MFC. Results from Illumina high throughput sequencing of 16S rRNA genes showed that there was difference anodic microbial community structure between M-MFC and ML-MFC. The microbial community in the ML-MFC was more diverse than in the M-MFC. This variation attributed to the differences in the design as well as the effect of sunlight to which these systems exposed to. M-MFC and ML-MFC shared the same dominant bacterial phyla; Proteobacteria and Firmicutes, and Synergistetes, with the most abundant bacterial genus in both MFCs belonging to Rhodopseudomonas. Sunlight has found promote the growth of the Rhodopseudomonas genus. The efficiency of the MFCs was reduced at the high OLR and longtime operated under open environment. [Display omitted]