Related Experiment Video
Updated: May 7, 2026
15:19
Development of Sulfidogenic Sludge from Marine Sediments and Trichloroethylene Reduction in an Upflow Anaerobic Sludge Blanket Reactor
Published on: October 15, 2015
Modeling trichloroethene reduction in a hydrogen-based biofilm
Youneng Tang1, Rosa Krajmalnik-Brown, Bruce E Rittmann
1Swette Center for Environmental Biotechnology, Biodesign Institute at Arizona State University, 1001 South McAllister Avenue, Tempe, AZ 85287-5701, USA
Summary
This study developed a multispecies biofilm model for a hydrogen-based membrane biofilm reactor to simultaneously remove trichloroethene (TCE) and nitrate. The model accurately simulated near-complete nitrate removal and significant TCE reduction with minimal chlorinated ethene accumulation.
Area of Science:
- Environmental microbiology
- Bioreactor engineering
- Contaminant remediation
Background:
- Trichloroethene (TCE) is a common groundwater contaminant.
- Nitrate contamination is prevalent in water sources.
- Simultaneous remediation of TCE and nitrate is challenging but desirable.
Purpose of the Study:
- To develop and validate a multispecies biofilm model for simultaneous TCE and nitrate reduction.
- To simulate the performance of a hydrogen-based membrane biofilm reactor (MBfR).
- To investigate factors influencing reductive dehalogenation in MBfRs.
Main Methods:
- Constructed a one-dimensional, steady-state multispecies biofilm model.
- Incorporated dual-substrate Monod kinetics and multiple solid/dissolved components.
- Simulated a bench-scale experiment using a H2-based MBfR.
Main Results:
- The model accurately predicted near-complete nitrate removal.
- Simulations showed incomplete TCE reduction and minimal accumulation of dichloroethene (DCE) and vinyl chloride (VC).
- Effluent concentrations were simulated under varying influent nitrate levels.
Conclusions:
- Simultaneous low concentrations of nitrate and chlorinated ethenes are achievable in H2-based MBfRs.
- Maintaining a favorable influent nitrate to TCE ratio is crucial for effective reductive dehalogenation by Dehalococcoides (DHC).
- The model provides valuable insights for optimizing MBfR design and operation for co-contaminant remediation.
Related Concept Videos
01:26Microbial Bioremediation of Hydrocarbons
Bioremediation is an environmentally sustainable process that employs living organisms—primarily microorganisms—to degrade or neutralize pollutants from contaminated environments. In oil spills and hydrocarbon pollution, bioremediation involves the use of hydrocarbon-degrading bacteria to transform toxic compounds into less harmful substances. This approach leverages natural microbial metabolic processes and is considered both cost-effective and ecologically favorable compared to physical or...
01:26Radical Substitution: Hydrogenolysis of Alkyl Halides with Tributyltin Hydride
Radical substitution reactions can be used to remove functional groups from molecules. The hydrogenolysis of alkyl halides is one such reaction, where the weak Sn–H bond in tributyltin hydride reacts with alkyl halides to form alkanes. Here, the reagent Bu3SnH yields tributyltin halide as a byproduct.
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation reactions,...
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation reactions,...
01:28Microbial Bioremediation of Pesticides
Pesticides often feature structurally complex chemical architectures, incorporating halogen groups and multiple aromatic rings. These characteristics confer high chemical stability, rendering many pesticides resistant to natural degradation processes. This resistance poses significant environmental concerns, as persistent pesticide residues can accumulate in ecosystems and affect non-target organisms.Despite the inherent stability of many pesticides, certain microorganisms possess the metabolic...
02:13Reduction of Alkenes: Catalytic Hydrogenation
Alkenes undergo reduction by the addition of molecular hydrogen to give alkanes. Because the process generally occurs in the presence of a transition-metal catalyst, the reaction is called catalytic hydrogenation.
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the surface of...
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the surface of...
01:28Reduction of Benzene to Cyclohexane: Catalytic Hydrogenation
Unlike the easy catalytic hydrogenation of an alkene double bond, hydrogenation of a benzene double bond under similar reaction conditions does not take place easily. For example, in the reduction of stilbene, the benzene ring remains unaffected while the alkene bond gets reduced. Hydrogenation of an alkene double bond is exothermic and a favorable process. In contrast, to hydrogenate the first unsaturated bond of benzene, an energy input is needed; that is, the process is endothermic. This is...
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
Catalytic hydrogenation of alkenes is a transition-metal catalyzed reduction of the double bond using molecular hydrogen to give alkanes. The mode of hydrogen addition follows syn stereochemistry.
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...