title: Treatment of anaerobic digestate supernatant in microbial fuel cell coupled constructed wetlands: Evaluation of nitrogen removal, electricity generation, and bacterial community response.
abstract: The objective of this study was to assess whether the improved configuration of vertical upflow constructed wetlands (CWs) coupled with aeration in the centre part and effluent recirculation can strengthen the treatment performance of high strength anaerobic digestate supernatant. Moreover, electricity generation and bacterial community characteristics were also examined. The results indicated that intermittent aeration in vertical upflow CWs significantly enhanced organic matter (>69%, 214-401g/m2d) and ammonium (>92%, 62-138g/m2d) removal, regardless of aeration position. However, the removal efficiency of total nitrogen (TN) was limited to 24%-40%. Effluent recirculation was examined to enhance TN removal up to 69% in the central aerated CW, as compared to 44% observed in the bottom aerated CW. Accordingly, significantly higher abundances of denitrifiers (nirK and nirS) and anaerobic ammonium oxidation bacteria (anammox) were found in the bottom layer of the central aerated CW. In addition, the central aerated CW coupled with effluent recirculation generated significantly higher electricity (maximum power density of 112mW/m2) than traditional bottom aerated CWs when integrated with a microbial fuel cell (MFC). Results confirmed the application potential of this new configuration of upflow CW integrated with central aeration and effluent recirculation.
authors.affiliation: Key Laboratory of Clean Utilization Technology for Renewable Energy in Ministry of Agriculture, College of Engineering, China Agricultural University, Beijing, PR China. Electronic address: wushubiao@gmail.com.
authors.forename: Shubiao
authors.initials: S
authors.lastname: Wu
authors.affiliation: Department of Bioscience, Aarhus University, Aarhus 8000C, Denmark.
authors.forename: Tao
authors.initials: T
authors.lastname: Lv
authors.affiliation: Key Laboratory of Clean Utilization Technology for Renewable Energy in Ministry of Agriculture, College of Engineering, China Agricultural University, Beijing, PR China.
authors.forename: Qimin
authors.initials: Q
authors.lastname: Lu
authors.affiliation: Key Laboratory of Clean Utilization Technology for Renewable Energy in Ministry of Agriculture, College of Engineering, China Agricultural University, Beijing, PR China.
authors.forename: Zeeshan
authors.initials: Z
authors.lastname: Ajmal
authors.affiliation: Key Laboratory of Clean Utilization Technology for Renewable Energy in Ministry of Agriculture, College of Engineering, China Agricultural University, Beijing, PR China.
authors.forename: Renjie
authors.initials: R
authors.lastname: Dong
keywords: Aeration position; High-strength wastewater; New configuration; Recirculation; Vertical upflow constructed wetlands