Role of Extracellular Polymeric Substances in a Methane Based Membrane Biofilm Reactor Reducing Vanadate

2018 ◽  
Vol 52 (18) ◽  
pp. 10680-10688 ◽  
Author(s):  
Chun-Yu Lai ◽  
Qiu-Yi Dong ◽  
Jia-Xian Chen ◽  
Quan-Song Zhu ◽  
Xin Yang ◽  
...  
Keyword(s):  
Extracellular Polymeric Substances ◽  
Biofilm Reactor ◽  
Membrane Biofilm Reactor

Modeling trichloroethene reduction in a hydrogen-based biofilm

2013 ◽  
Vol 68 (5) ◽  
pp. 1158-1163 ◽  
Author(s):  
Youneng Tang ◽  
Rosa Krajmalnik-Brown ◽  
Bruce E. Rittmann
Keyword(s):  
Extracellular Polymeric Substances ◽  
Complete Removal ◽  
Denitrifying Bacteria ◽  
Biofilm Reactor ◽  
Reductive Dehalogenation ◽  
Monod Kinetics ◽  
Membrane Biofilm Reactor ◽  
Scale Experiment ◽  
The One ◽  
Dissolved Components

We constructed a multispecies biofilm model for simultaneous reduction of trichloroethene (TCE) and nitrate (NO3−) in the biofilm of a H2-based membrane biofilm reactor (MBfR). The one-dimensional model includes dual-substrate Monod kinetics for a steady-state biofilm with multiple solid and dissolved components. The model has five solid components: autotrophic denitrifying bacteria (ADB), heterotrophic denitrifying bacteria (HDB), Dehalococcoides (DHC), inert biomass (IB), and extracellular polymeric substances (EPS). The model has eight dissolved components: NO3−, TCE, dichloroethene (DCE), vinyl chloride (VC), ethene, hydrogen (H2), substrate-utilization-associated products (UAP), and biomass-associated products (BAP). We used this model to simulate a bench-scale experiment in a H2-based MBfR. The model simulated the trends well: almost complete removal of nitrate, incomplete reduction of TCE, and almost no accumulation of DCE and VC. To gain insight into reductive dehalogenation in a H2-based MBfR, we also simulated the concentrations of nitrate, TCE, DCE, VC, and ethene in the reactor effluent while varying the influent nitrate concentration. Simultaneous low concentrations of nitrate and the three chlorinated ethenes can occur as long as the influent ratio of NO3− to TCE is not too large, so that DHC are a significant fraction of the biofilm.

A membrane biofilm reactor achieves aerobic methane oxidation coupled to denitrification (AME-D) with high efficiency

2008 ◽  
Vol 58 (1) ◽  
pp. 83-87 ◽  
Author(s):  
O. Modin ◽  
K. Fukushi ◽  
F. Nakajima ◽  
K. Yamamoto
Keyword(s):  
Methane Oxidation ◽  
High Efficiency ◽  
Biofilm Reactor ◽  
Practical Application ◽  
Suspended Culture ◽  
Consumption Ratio ◽  
Membrane Biofilm Reactor ◽  
Nitrate Consumption ◽  
Attached Culture ◽  
Aerobic Methanotrophs

Methane would potentially be an inexpensive, widely available electron donor for denitrification of wastewaters poor in organics. Currently, no methanotrophic microbe is known to denitrify. However, aerobic methane oxidation coupled to denitrification (AME-D) has been observed in several laboratory studies. In the AME-D process, aerobic methanotrophs oxidise methane and release organic metabolites and lysis products, which are used by coexisting denitrifiers as electron donors for denitrification. Due to the presence of oxygen, the denitrification efficiency in terms of methane-to-nitrate consumption is usually low. To improve this efficiency the use of a membrane biofilm reactor was investigated. The denitrification efficiency of an AME-D culture in (1) a suspended growth reactor, and (2) a membrane biofilm reactor was studied. The methane-to-nitrate consumption ratio for the suspended culture was 8.7. For the membrane-attached culture the ratio was 2.2. The results clearly indicated that the membrane-attached biofilm was superior to the suspended culture in terms of denitrification efficiency. This study showed that for practical application of the AME-D process, focus should be placed on development of a biofilm reactor.

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