Extension de la technique des bassins à double fond aux grandes surfaces d'élevage

The use, as an aquaculture technique, of the double bottom supporting a sediment layer has numerous advantages. As far as the sediment is concerned (essential in the case of the Penaeid shrimp), this technique alone allows the sediment to stay clean as it is constantly oxidized through the percolation it creates. The water running through the sediment can either be drained off or recycled: - It has to be drained off in the case of heavy loads as it may contain some toxic products, incompletely decomposed by the bacterial activity, and especially some unsaturated short chain hydrocarbon (hexenes for most of them). - Otherwise, it can be recycled, through the use of an "Air-lift" system allowing its oxygenation at the same time. In this case, and if the set parameters are not disproportionate, the double bottom becomes a very efficient filter as it associates the aerobic metabolic decomposition producing mineral salts to the mechanical filtration.