La Mer et les Rejets Urbains. Bendor, 13-15 juin 1990.
IFREMER. Actes de Colloques 11. pp 205 à 220
14
APPLICATION D’UN MODÈLE SEDIMENTAIRE AU DEVENIR DES
CONTAMINANTS PARTICULAIRES
P. LE HIR, J.F. GUILLAUD, Ph. BASSOULLET, J. L'YAVANC
IFREMER, Centre de BREST, DRO/EL, B.P. 70, 29280 PLOUZANE
ABSTRACT - In order to assess the fate of either particulate or adsorbed contaminants frorn urban sewage
disposai, a cohesive sédiment transport model has been developed. Several dissolved and particulate contituents
can be simultaneously computed, the later being followed in the surficial sédiment according to the déposition
events. The becoming of a theoretical conservative discharge is described by the means of a so-called “nominal"
impact, Le. the maximum concentrations pattern in the study area, and the transit time from the outfall. The
application to enteric bacteria discharge showed off the effect of differentiated survival laws on the relative
abondance of free and attached bacteria. Moreover, the effect ofturbidity on the light atténuation within the water
column, and then on bacteria mortality, has been taken into account. Lastly, the simulation of phosphate discharge
and ils adsorption on suspended sédiment according to a partitioning law has been achieved and the results are
in good agreement with field measurements. As a conclusion the model proved efficient even for water modelling
applications, but should be considered as a tool for applied research, because of the necessary field or laboratory
experiments for calibrating the process laws.
INTRODUCTION
De nombreux contaminants issus des effluents urbains sont concernés par le transport des
sédiments. Ils peuvent être directement sous forme particulaire, (c'est le cas d'une part
importante de la matière organique), ou plus souvent fixés aux particules (micropolluants
métalliques ou organiques adsorbés, bactéries liées, phosphate etc.), ou encore avoir un
comportement dans le milieu marin influencé par la turbidité induite par les matières en
suspension, comme cela a été montré pour la mortalité des bactéries (Pommepuy et al.,
1990).
205
IFREMER. Actes de Colloques 11. pp 205 à 220
14
APPLICATION D’UN MODÈLE SEDIMENTAIRE AU DEVENIR DES
CONTAMINANTS PARTICULAIRES
P. LE HIR, J.F. GUILLAUD, Ph. BASSOULLET, J. L'YAVANC
IFREMER, Centre de BREST, DRO/EL, B.P. 70, 29280 PLOUZANE
ABSTRACT - In order to assess the fate of either particulate or adsorbed contaminants frorn urban sewage
disposai, a cohesive sédiment transport model has been developed. Several dissolved and particulate contituents
can be simultaneously computed, the later being followed in the surficial sédiment according to the déposition
events. The becoming of a theoretical conservative discharge is described by the means of a so-called “nominal"
impact, Le. the maximum concentrations pattern in the study area, and the transit time from the outfall. The
application to enteric bacteria discharge showed off the effect of differentiated survival laws on the relative
abondance of free and attached bacteria. Moreover, the effect ofturbidity on the light atténuation within the water
column, and then on bacteria mortality, has been taken into account. Lastly, the simulation of phosphate discharge
and ils adsorption on suspended sédiment according to a partitioning law has been achieved and the results are
in good agreement with field measurements. As a conclusion the model proved efficient even for water modelling
applications, but should be considered as a tool for applied research, because of the necessary field or laboratory
experiments for calibrating the process laws.
INTRODUCTION
De nombreux contaminants issus des effluents urbains sont concernés par le transport des
sédiments. Ils peuvent être directement sous forme particulaire, (c'est le cas d'une part
importante de la matière organique), ou plus souvent fixés aux particules (micropolluants
métalliques ou organiques adsorbés, bactéries liées, phosphate etc.), ou encore avoir un
comportement dans le milieu marin influencé par la turbidité induite par les matières en
suspension, comme cela a été montré pour la mortalité des bactéries (Pommepuy et al.,
1990).
205