colmatage à l'hydroxyde ferrique

OBS: Colmatage chimique. Selon la nature des eaux et leur teneur en matières dissoutes il n'est pas à exclure la précipitation sur le géotextile de divers sels, principalement le carbonate de calcium [...] On notera que des eaux chargées en sel de fer peuvent, sous l'action de micro-organismes, déposer sur les géotextiles de l'hydroxyde ferrique qui à terme obturera totalement le géotextile.

CONT: Where iron particles are present in the soil or the water, they can ... be the source of another potential hazard ... Oxidation and other chemical reactions can change the size of the ferruginous particles with time, giving rise to unexpected clogging of the geotextile ... A ... rare form of ferric clogging due to the presence of certain bacteria in geotextile-wrapped drains, has been reported ... These bacteria may be subdivided into two groups, one of which oxidizes dissolved iron in the drain water to form a precipitate, and the other of which acts on dissolved organic matter in the drain water, to release iron which may then be oxidized. The result of this bacterial activity is a deposit of bacterial gel containing rusty layers in the drain core.