title: Assessing microbial competition in a hydrogen-based membrane biofilm reactor (MBfR) using multidimensional modeling.
abstract: The membrane biofilm reactor (MBfR) is a novel technology that safely delivers hydrogen to the base of a denitrifying biofilm via gas-supplying membranes. While hydrogen is an effective electron donor for denitrifying bacteria (DNB), it also supports sulfate-reducing bacteria (SRB) and methanogens (MET), which consume hydrogen and create undesirable by-products. SRB and MET are only competitive for hydrogen when local nitrate concentrations are low, therefore SRB and MET primarily grow near the base of the biofilm. In an MBfR, hydrogen concentrations are greatest at the base of the biofilm, making SRB and MET more likely to proliferate in an MBfR system than a conventional biofilm reactor. Modeling results showed that because of this, control of the hydrogen concentration via the intramembrane pressure was a key tool for limiting SRB and MET development. Another means is biofilm management, which supported both sloughing and erosive detachment. For the conditions simulated, maintaining thinner biofilms promoted higher denitrification fluxes and limited the presence of SRB and MET. The 2-d modeling showed that periodic biofilm sloughing helped control slow-growing SRB and MET. Moreover, the rough (non-flat) membrane assembly in the 2-d model provided a special niche for SRB and MET that was not represented in the 1-d model. This study compared 1-d and 2-d biofilm model applicability for simulating competition in counter-diffusional biofilms. Although more computationally expensive, the 2-d model captured important mechanisms unseen in the 1-d model.
authors: Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, Indiana, 46556.|Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan.
authors: Kelly J
authors: KJ
authors: Martin
authors: Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Delft, the Netherlands.
authors: Cristian
authors: C
authors: Picioreanu
authors: Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, Indiana, 46556. nerenberg.1@nd.edu.
authors: Robert
authors: R
authors: Nerenberg
mesh_terms: D018441:Biofilms / Q000254:growth & development*; D018533:Biomass; D019149:Bioreactors / Q000382:microbiology*; D058440:Denitrification; D006859:Hydrogen; D008567:Membranes, Artificial; D059013:Microbial Consortia / Q000502:physiology*; D008954:Models, Biological
chemical_list: D008567:Membranes, Artificial; D006859:Hydrogen
keywords: MBfR; biofilm model; denitrification; detachment; hollow fiber membrane reactor