New insight into CO2-mediated denitrification process in H2-based membrane biofilm reactor: An experimental and modeling study

Minmin Jiang; Junjian Zheng; Patricia Perez-Calleja; Cristian Picioreanu; Hua Lin; Xuehong Zhang; Yuanyuan Zhang; Haixiang Li; Robert Nerenberg

doi:10.1016/j.watres.2020.116177

New insight into CO₂-mediated denitrification process in H₂-based membrane biofilm reactor: An experimental and modeling study

Water Res. 2020 Oct 1:184:116177. doi: 10.1016/j.watres.2020.116177. Epub 2020 Jul 13.

Authors

Minmin Jiang¹, Junjian Zheng², Patricia Perez-Calleja³, Cristian Picioreanu⁴, Hua Lin⁵, Xuehong Zhang⁵, Yuanyuan Zhang², Haixiang Li⁶, Robert Nerenberg⁷

Affiliations

¹ Guilin University of Technology, College of Environmental Science and Engineering, 319 Yanshan Street, Guilin, 541006, China; University of Notre Dame, Department of Civil and Environmental Engineering and Earth Sciences, 156 Fitzpatrick Hall, Notre Dame, IN, 46556, USA.
² Guilin University of Electronic Technology, College of Life and Environmental Science, 1 Jinji Road, Guilin, 541004, China.
³ University of Notre Dame, Department of Civil and Environmental Engineering and Earth Sciences, 156 Fitzpatrick Hall, Notre Dame, IN, 46556, USA.
⁴ Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, the Netherlands.
⁵ Guilin University of Technology, College of Environmental Science and Engineering, 319 Yanshan Street, Guilin, 541006, China.
⁶ Guilin University of Technology, College of Environmental Science and Engineering, 319 Yanshan Street, Guilin, 541006, China. Electronic address: 2011042@glut.edu.cn.
⁷ University of Notre Dame, Department of Civil and Environmental Engineering and Earth Sciences, 156 Fitzpatrick Hall, Notre Dame, IN, 46556, USA. Electronic address: nerenberg.1@nd.edu.

PMID: 32693267
DOI: 10.1016/j.watres.2020.116177

Abstract

The H₂-based membrane biofilm reactor (H₂-MBfR) is an emerging technology for removal of nitrate (NO₃^-) in water supplies. In this research, a lab-scale H₂-MBfR equipped with a separated CO₂ providing system and a microsensor measuring unit was developed for NO₃^- removal from synthetic groundwater. Experimental results show that efficient NO₃^- reduction with a flux of 1.46 g/(m²⋅d) was achieved at the optimal operating conditions of hydraulic retention time (HRT) 80 min, influent NO₃^- concentration 20 mg N/L, H₂ pressure 5 psig and CO₂ addition 50 mg/L. Given the complex counter-diffusion of substrates in the H₂-MBfR, mathematical modeling is a key tool to both understand its behavior and optimize its performance. A sophisticated model was successfully established, calibrated and validated via comparing the measured and simulated system performance and/or substrate gradients within biofilm. Model results indicate that i) even under the optimal operating conditions, denitrifying bacteria (DNB) in the interior and exterior of biofilm suffered low growth rate, attributed to CO₂ and H₂ limitation, respectively; ii) appropriate operating parameters are essential to maintaining high activity of DNB in the biofilm; iii) CO₂ concentration was the decisive factor which matters its dominant role in mediating hydrogenotrophic denitrification process; iv) the predicted optimum biofilm thickness was 650 µm that can maximize the denitrification flux and prevent loss of H₂.

Keywords: CO(2) addition; Denitrification; H(2)-based membrane biofilm reactor (H(2)−MBfR); Mathematical model.

MeSH terms

Biofilms
Bioreactors*
Carbon Dioxide
Denitrification*
Nitrates

Substances

Nitrates
Carbon Dioxide