1. General Model Information

Name: Microbial Benthos Method

Acronym: MBM

Main medium: aquatic
Main subject: biogoechemical
Organization level:
Type of model: ordinary differential equations, partial differential equations
Main application:
Keywords: water quality, streams, pollution, sediment, dissolved organic matter, biofilm, benthic microorganisms, flow, transport, convection-dispersion equation


Dr.Bernard Cazelles
Centre de Bioinformatique and INSERUM U263
T53, 2 Place Jussieu
F-75251 Paris, France
Phone: +33 1-4427-7722
Fax : +33 1-4326-3830
email: cazelles@urbb.jussieu.fr


Cazelles, B.


The model was developed to simulate self-purification mechanisms that occur in a small stream heavely polluted by an organic load. As the main detritical processes that occur in small streams take place in the sediment, the model was applied to simulate the dynamics of both dissolved organic matter and benthic microorganisms. The physical part of the model included a hydrodynamical component derived from Saint-Venant`s equations, coupled to a transport model based on a convection-dispersion equation under uniform, unsteady flow conditions. The simulation of the biodegradation machanisms was based on biofilm kinetics. The linkage between hydrophysical and benthic mechanisms affords a dynamic description of the system. Transport modeling provides a picture in space and time of the evelution of organic carbon concentration in water. This evolution makes it possible to predict the fate of the benthic biological component. The main characteristics of the model were
STATE VARIABLES: cross sectional area, discharge, organic substrate in the flow, biofilm, organic substrate, microbial biofilm biomass.
FORCING FUNCTION: temperature, tributary inputs.
MAIN PARAMETERS: disperson coefficient, transfer velocity at the interface, biofilm shearing rate, maximum growth rate, bacterial decay rate, half saturation coefficient, biofilm cellular density.
INPUTS: Stream length, geometric description of the stream, time series of the discharge at the point x=0, time series of the organic load at x=0.

Model purpose
The purpose of the model was twofold: (i) to simulate the self-purification mechanisms in a lotic ecosystem and more generally, organic matter decomposition processes; (ii) to couple the two approaches which are commonly used in aquatic modeling, the transport oriented and the ecology oriented approaches.

Source of the Abstract:
Joergensen S.E., B. Halling-Soerensen and S.N Nielsen (Edts.) 1996: Handbook of Environmental and Ecological Modelling. CRC Press Boca Raton et al. 672 pp.

II. Technical Information

II.1 Executables:

Operating System(s): Mainframe

II.2 Source-code:

Programming Language(s): Fortran 77

II.3 Manuals:

II.4 Data:

III. Mathematical Information

III.1 Mathematics

III.2 Quantities

III.2.1 Input

III.2.2 Output

IV. References

Cazelles, B.,Fontvieille and Chau, N.P., 1991. Self-purification in a lotic ecosystem: a model of sissolved organic carbon and benthic microorganisms dynamic. Ecol. Modelling,58, 91-117.

V. Further information in the World-Wide-Web

VI. Additional remarks

This original organic carbon based model designed for the Albenche river could be applied to other heterotrophic streams where decomposition processes occur mainly in the benthic compartment, in addition to/or replacing the usualoxygen deficit models. The biological part of the model has been used to optimize fixed biomass reactors used in waste water treatment from pilot scale to industrial scale.

Last review of this document by: R. Patzak : 18.August 1997 -
Status of the document:
last modified by Tobias Gabele Wed Aug 21 21:44:45 CEST 2002

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